Test 1 Flashcards

Question

Virulence

Answer 1

the degree of pathogenicity

Answer 2

released from the cell; made in the cell

Answer 3

1. A-B toxins 2. Membrane disrupting toxins (Leukocidins kill white blood cells (phagocytes), Hemolysins destroy erythrocytes) 3. Superantigens

Answer 4

Most exotoxins(i.e. tetanus) are A-B toxin • A-B toxins consist of two polypeptides. • The A polypeptide is the active enzyme and the B polypeptide is a binding component • B binds to the cell, the complete toxin is taken into the cell, the two subunits separate, and the A subunit enzymatically kills the cell.

Answer 5

Cause non-specific activation of T-cells • result in polyclonal T cell activation and massive cytokine release. • Produced by pathogenic microbes (including viruses, mycoplasma, and bacteria) • Indiscriminate binding to MHC class II molecule on the antigen presenting cell and and T helper cell receptor • 1/1000(Superantigens) vs. 1/5 cells by an antigen • Nausea, vomiting, fever\> shock

Answer 6

Toxic shock syndrome in humans is caused by a superantigen

Answer 7

Plasmids are smaller circular DNA present in Bacteria Bacteriophages are virus particles which attack Plasmids and bacteriophages may carry genes for antibiotic resistance, toxins, capsules and fimbriae and can mediate transfer. Plasmid genes; Tetanus neurotoxin Staphylococcus enterotoxin(superantigens) Bacteriophage genes; Corynebacterium diphtheria (Diphtheria toxin), Clostridium botulinum (Botulinum toxin), E. coli O157 H7( Shiga toxin)

Answer 8

is the process by which one bacterium( Bacterium with a fertility factor) transfers genetic material to another through direct contact.

Answer 9

is the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surroundings and taken up through the cell membrane(s)

Answer 10

is the process by which DNA is transferred from one bacterium to another by a virus

Answer 11

virulence factor Microbes come together in masses cling to surfaces, produce extracellular substances and take in nutrients and forms a biofilm Eg. Dental Plaque Pseudomonas aeruginosa biofilms in cystic fibrosis patients

Answer 12

1. the bacteria appear relatively innocuous as they quietly grow in number 2. When their population reaches a certain level, instant changes occur in their behavior, appearance, and metabolism. 3. These changes culminate in an infection that can ambush and overwhelm our immune system defenses.

Answer 13

organisms those do not cause disease in a healthy host, with a healthy immune system

Answer 14

equipped with virulence genes for adherence, invasion, evasion from the immune system and toxins

Answer 15

Hospital acquired infections Eg. Methicillin resistant Staphylococcus aureus Clostridium difficile

Answer 16

extracellular pathogens

Answer 17

Eg. Rickettsia, Chlamydia

Answer 18

(can survive extracellular or intracellular) Eg. Mycobacterium

Answer 19

lipopolysaccharide

Answer 20

Thick Peptiodoglycan

Answer 21

Mycolic Acid

Answer 22

Bacterial protein production by ribosomes

Answer 23

Production of protein

Answer 24

Drugs that destroy microbes, prevent their multiplication or growth or prevent their pathogenic effect • Differ in their physical, chemical and pharmacological properties • Differ in their antibacterial spectrum of activity • Differ in their mechanism THESE DO HAVE TO KILL THE MICROBE, THEY CAN JUST PREVENT ITS GROWTH

Answer 25

When the patient have a treatable microbial infection

Answer 26

Antibotics- produced by living organism, Antimicobrial is a broader term

Answer 27

location of the infections, likely pathogens involved, which antimicrobials are likely effective against a particular pathogen at a particular site

Answer 28

Cost, (type, dose and duration), safety, ease of use, and possible emergence of resistance

Answer 29

chemical substance produced by a microorganism that inhibits the growth of or kills other microorganisms.

Answer 30

a chemical substance derived from a biological source or produced by chemical synthesis that kills or inhibits the growth of microorganisms.

Answer 31

produced by bacteria or fungus (Streptomycin, penicillin, tetracycline)

Answer 32

chemically-altered natural compound (ampicillin, amikacin)

Answer 33

chemically designed in the lab (sulfonamide, enrofloxacin, marbofloxacin)

Answer 34

A. Chemicalfamilystructure B. Mode of action C. Type of antimicrobial activity D. Spectrum of antibacterial activity

Answer 35

•Know the drugs •Know the microbiology •Know the patient

Answer 36

inhibitors of cell wall synthesis inhibitors of protein synthesis inhibitors of membrane function inhibitors of nucleic acid synthesis (anti-metabolites)

Answer 37

Done to figure out which antimicrbioals are the best to treat certain infections

Answer 38

1. Dilution (broth/agar) 2. Diffusion (disk)- aka Kirby Bauer Test

Answer 39

A drug concentration above which an organism is considered resistant and at or below this value organism is susceptible to that drug. Three Break point values are set at Susceptible, Intermediate, or Resistant IMPORTANT FOR LABS DOING THIS TEST

Answer 40

Minimum amount of drug required to inhibit bacterial growth Drugs with lower MIC values are better choices

Answer 41

Disk Diffusion (‘Kirby Bauer’) * Must use a bacterial isolate in pure culture * Standardized bacterial inoculum spread on an agar plate * Single-concentration antimicrobial disks are used * Growth inhibition zone diameter measured * Published reference breakpoints (zone size) to interpret results * Different drugs will have different zone sizes based on the published data

Answer 42

• multiple dilutions of antimicrobial agents (usually 2-fold serial dilutions) Use published reference breakpoints to interpret • Measure AND report growth inhibition endpoint (MIC) (MIC reported in micrograms per milliliter)

Answer 43

above MIC in the body

Answer 44

Measures MIC

Answer 45

active against a wide variety of bacteria Eg. Tetracycline

Answer 46

affect only a narrow range of bacteria Eg. Penicillin

Answer 47

* Mixed infections * Prevention of antimicrobial resistance * To increase effectiveness in treating some infections Synergistic ( sequential action at different sites, enhanced uptake- beta lactam and aminoglycosides, interference with resistance mechanism, Drugs metabolized to active metabolites (Enrofloxcin to Ciprofloxacin)

Answer 48

preexisting genomic property i.e. Mycoplasa does not have a cell wall, Therefore, you can't use beta lactones

Answer 49

new genetically encoded trait not representative of the species (acquired by mutation or horizontal gene transfer) Processes that bacteria can aquire virulence factors: -conjugation

Answer 50

* Enzymatic destruction or inactivation of drug * Prevention of penetration to target sites within microbe * Alteration of drugs target site * Rapid efflux of antibiotics

Answer 51

• Prudent drug use - maximize efficacy of therapeutic regimens - restrict extra-label use to high risk patients - observe withdrawal period - use antimicrobials of limited human health concern - use alternative therapies • Pathogen control - animal waste management - reduce contamination in slaughter and processing - maintain herd health and infection control • Policy - control of drug use in food animals - national antimicrobial resistance monitoring system - educational efforts

Answer 52

Vancomycin Vancomycin resistant Enterococcus (VRE)

Answer 53

Growth Promotion

Answer 54

Extra Label Use

Answer 55

D. Know the Client

Answer 56

TRUE; because you can use a lower dose, but remember that MIC is not the only factor(microbe, site of infection etc)

Answer 57

True- you MUST have a pure culture

Answer 58

D. Kirby Bauer DOES NOT measured MIC accurately

Answer 59

1. Direct detection of the agent (simple/ differential staining, antibody staining) 2. Isolation and identification 3. Direct detection of antigens, toxins (Immunology techniques such as ELISA0 4. Nucleic acid detection(PCR)

Answer 60

Antibodies(Eg,Brucella infection), Cell mediated immune response(eg.TB)---- very rare and only available for certain conditions

Answer 61

Ideal test has high sensitivity and high specificity

Answer 62

percentage of true positives in a sample population that are correctly identified as positive by a test.

Answer 63

percentage of true negatives in a sample population that are correctly identified as negative by a test.

Answer 64

percentage of all positive test results that are true positives.

Answer 65

percentage of all negative test results that are true negatives.

Answer 66

Predictive values associated with individual test results vary with disease prevalence

Answer 67

more accurate results.

Answer 68

* Collect from actual site of infection * Minimise contamination * Collect early in the stage of disease process * Use appropriate transportation * Collect before the initiation of antimicrobial therapy

Answer 69

better to submit the material itself

Answer 70

the bacteria will produce lots gas

Answer 71

Gram Positive Purple(Crystal violet) Eg: Streptococcus pyogenes Stapylococcus aureus Gram Negative- Pink (Safranin) Escherichia coli Pasteurella multocida Gram stain -Gram Positive = Thick Peptidoglycan

Answer 72

Acid fast positive organism stains: Pink Acid fast negative organism stains: Blue Acid fast stain –Acid fast + =mycolic acid

Answer 73

Sensitivity is very poor ## Footnote Blood • CSF • Mycoplsama, spirochetes( can not be stained)

Answer 74

Collection, • Cystocentesis preferred over catheterization • Urethral contamination occurs in free catch and catheterized samples • \<105/ml- probable contamination( • Gram staining(2 bacteria/ oil immersion) • Capped syringe, sterile container • Refrigerate if cannot be cultured if cannot be cultured immediatly • May use Urine preservation tubes

Answer 75

* Syringe * Remove air * Anaerobic transport medium •Lavages or washes use a buffered solution •Saline vs. lactated ringer’s solution

Answer 76

* 2-3 gms * Leak proof container * Repeated culture needed in shedding/chronic infections

Answer 77

* Several specimens over a period of time, onset of fever, * 3- 4 in first 1.5 -3 hours

Answer 78

* Portion of a tissue * Multiple specimens * Collect first during necropsy * Sealed leak proof container * Refrigerate if delivery delayed

Answer 79

Normal flora Vs. Pathogens Correlate with clinical signs and the organism Quantitation- light, moderate, heavy (Isolation of four or more organism; Most likely contamination)

Answer 80

May be due to sampling, transport, storage issues, antimicrobial therapy, Fastidious organisms or when specific procedures needed Consult with clinical microbiologist

Answer 81

transport in secondary container that is leakproof, puncture proof and contains liquid absorbent

Answer 82

Gram Negative cocci

Answer 83

• Non culture based from clinical samples • For identification of isolates. * Conventional PCR * Real Time PCR * What is the limitation for PCR identification? You have to know what you are dealing with

Answer 84

(EIA, agglutination, FA, etc.) | (tests use antibody reagents to detect antigens in serum, feces, urine, tissue.)

Answer 85

(HPLC, GLC, MALDI-TOF- MS) (analysis of total cell fatty acids/proteins; limited use on clinical specimens)

Answer 86

(Limulus amoebocyte assay) (test for LPS, adapted from clotting mechanism of horseshoe crab)

Answer 87

• Humoral (antibody) Response Eg: Agglutination, precipitation, ELISA • Cell mediated immune response Eg: Tuberculin reaction, Interferon gamma test Generation of an immune response requires time and immune response may persist

Answer 88

prior antigen exposure, vaccination, cross-reactions

Answer 89

anergy, immunosuppression

Answer 90

All have a b-Lactam Ring Members of the group Penicillins,( Ampicillin, Amoxicillin, Ticarcillin) Cephalosporins(1st, 2nd,3rd, 4th Generations) Carbapenems (Imipenem) Monobactams (Aztreonam) Mechanism of action Inhibit Cell wall synthesis(transpeptidation step) in the peptidoglycan synthesis, Stimulate autolysins which degrade peptidoglycan b-Lactam antimicrobials differ in their spectrum of activities Some are effective against both Gram Negatives and Gram positives Some are effective against only Gram Negatives than Gram positives or vice versa Vary in their absorption, toxicity, and their ability to penetrate tissues or blood brain barrier Bactericidal antimicrobials- KILL THE BACTERIA Excretion through kidneys Time Dependant killing- you have to have a concentration over a period of time

Answer 91

Mechanism of action Inhibit Cell wall synthesis(transpeptidation step) in the peptidoglycan synthesis, Stimulate autolysins which degrade peptidoglycan

Answer 92

Resistance mechanisms; • b-Lactamase(enzyme which cleaves b lactam ring) production • Extended Spectrum b lactamase • Alteration in penicillin binding proteins

Answer 93

* Glycopeptides(Vancomycin, daptomycin) * Last resort antimicrobial in S. aureus, and Enterococcus • Fosfomycin, bacitracin

Answer 94

Staphylococcus Streptococcus Enterococcus Micrococcus

Answer 95

Facultative anaerobic catalase positive cocci Exceptions: Anaerobic species;S.sacharolyticus, S.aureus subsp.anaerobius Classic opportunistic pathogens Natural habitat is skin and mucous membranes May be a part of resident or transient flora

Answer 96

S. pseudintermedius

Answer 97

Enzyme which Convert fibrinogen to Fibrin

Answer 98

Suppurative conditions • Superficial: skin and soft tissue infections pyoderma, folliculitis, furunculosis, wound infections • Deep infections Abscess, cellulitis, mastitis, pyomyositis, Necrotizing fasciitis and myositis * Infections of other body systems * Empyema, osteomyelitis, arthritis, endocarditis, pneumonia,otitis,sinusitis, meningitis • Invasive bacteremia

Answer 99

Chronic persistent relapsing infections in staph infections

Answer 100

* Toxin mediated diseases: * Staphylococcal toxic shock syndrome(TSST-1) * Staphylococcal food poisoning(Staphylococcal enterotoxin) •Staphylococcal scalded skin syndrome (Exfoliative toxins) All of these are superantigens!

Answer 101

Causes indiscriminate binding to MHC Class II receptor and releasing lots of cytokines and T cells

Answer 102

* Protein A: Bind to FC portion of IgG- prevents phagocytosis * Hemolysins: lyse RBC and other body cells * Proteases: Destroy tissues * Hyaluronidase: destroy connective tissue * Lipases * Alpha toxins: membrane damaging toxin * Leukocidin (role in necrotizing fasciitis and pneumonia in dogs) * Exfoliative toxins * Biofilm formation

Answer 103

Wound infections, surgical site infections, septic arthritis, osteomyelitis, Urinary tract infections, endocarditis, peritonitis, ocular infections, ear infections * Necrotizing fasciitis and necrotizing pneumonia * Bacterial folliculitis and furunculosis

Answer 104

“Epidermal barriers are less well developed” ??? Thin stratum corneum Lack of Follicular Plug

Answer 105

Direct examination of the specimen Gram positive cocci in clusters are indicative Evidence of inflammation with abundance of neutrophils is highly suggestive Culture (infection or contamination especially when CoNS is isolated) Semiquantitative culture is useful (heavy, moderate, few) PCR (What are the issues associated with PCR in diagnosing Staphylococcal skin infections?- There is LOTS OF CONTAMINATION)

Answer 106

Exudative epidermitis caused by S. hyicus

Answer 107

Cattle: S. aureus • Sub-acute chronic or acute **mastitis** • Per-acute mastitis (Gangrenous mastitis)

Answer 108

Ulcerative Pododermatitis (S. aureus)

Answer 109

BIRDS Bumble foot; S. aureus

Answer 110

Botryomycosis- Rodents, Human, Horses Chronic pyogranulomatous inflammation Most common isolate : S. aureus

Answer 111

Antimicrobial susceptibility testing is a critical component Variability in susceptibility pattern Emergence of multidrug resistant Staphylococci Make sure that the labs follow appropriate guidelines CLSI or EUCAST Inducible Clindamycin resistance in macrolide resistant Staphylococcus **Nothing will substitute culture and AST** Therapy depends on Infection site and severity Species variation and geographic variations, 1st generation Cephalosporins (Cephalexin) are the first line of treatment choice Quinolones Not the first line of choice(resistance efficacy not well documented, and due to rapid development of resistance

Answer 112

All staphylococcus isolates which are macrolide(erythromycin) resistant should be considered Clindamycin resistant unless otherwise confirmed by a D-test

Answer 113

b lactamase -mediated resistance common Methicillin resistance becoming problematic (MRSA & MRSP) Mediated by mecA gene resulting in altered penicillin binding protein(PB2a) **Multidrug** resistance (macrolide, aminoglycoside, tetracycline, potentiated sulfas)

Answer 114

Pulse Field Gel Ectrophoreisis

Answer 115

open, flush and use local treatment- YOU DON"T NEED AN ANTIMICROBIAL!

Answer 116

Antibodies

Answer 117

Sensitivity

Answer 118

Specificity

Answer 119

Herd A The higher the prevalence of a disease, the higher the predicitive value

Answer 120

D. Urine collected and shipped to the lab in a syringe with a needle attached to it

Answer 121

Gram-positive cocci in pairs or chains * Facultative anaerobe (aerobic and anaerobic) * Catalase negative * Many species can be pathogenic * Commensal of oral cavity, nasopharynx, skin, GI and Genital tracts • Hemolytic activity used for classification (a, b, g)

Answer 122

Acute suppurative – local to systemic Immunologic post-streptococcal diseases (mostly human) Subacute (vegetative) endocarditis Chronic mastitis Streptococcal toxic shock syndrome (STSS) Necrotizing fasciitis and myositis(NFM)

Answer 123

used for Strep ## Footnote based on cell wall carbohydrates (A,B,C, D,E, F, G,H)

Answer 124

Capsules Peptidoglycan Teichoic/lipoteichoic acid M protein- VERY IMPORTANT IN STRANGLES Ig binding proteins Streptokinase, Streptococcal pyrogenic exotoxins (superantigens)

Answer 125

Scarlet fever in humans

Answer 126

Group G streptococcus infections in dogs and cats * S. canis * Commensal of skin and mucous membrane Kittens and puppies Infection from vagina or Umbilical vein\>Peritoneal cavity, liver\>bacteremia Septicemia and embolic lesions in heart and lung Skin ulceration and chronic respiratory infection necrotizing sinusitis and meningitis, necrotizing fasciitis with skin ulceration to toxic shock-like syndrome, sepsis, and death. Flesh eating bacteria

Answer 127

Pathogenic or commensal organism usually associated with pigs. At least 35 serotypes of S. suis Type 2 is usually isolated most often from clinical cases in pigs, and is the predominant isolate from humans. Weanlings and growing pigs, Septicemia, serositis, meningitis, polyarthritis, pneumonia, abortions, abscesses and endocarditis.

Answer 128

Streptococcus suis and streptococcus iniae

Answer 129

Acute fulminating septicemia in fish chronic form limited to the central nervous system. **meningoencephalitis**, perineuritis, polyserositis, epicarditis, myocarditis, and cellulitis.

Answer 130

Streptococcus porcinus Jowl Abscess in pigs

Answer 131

* Do not react with Lancefield grouping sera. * Definitive species identification is difficult. * These bacteria can be found in the mouth, gastrointestinal tract and vagina of healthy humans, as well as in animals, dairy products and other sources. * Human infections

Answer 132

* Streptococcus pneumoniae: pneumococcal pneumonia, septicemia and meningitis in humans * Pneumonia in guinea pigs and rodents • Domestic pets can act as carriers

Answer 133

* Beta hemolytic, Group C Streptococcus * Usually has marked mucoid appearance due to abundant hyaluronic acid capsule • Must be distinguished from other equine group C S. zooepidemicus and S. equisimilis, by sugar fermentation tests or nucleic acid-based testing Equids are the only known hosts All ages are susceptible, average age \<2 yr Weaned foals, yearlings most susceptible \<4 mo usually protected by maternal antibodies Worldwide distribution, prevalence varies morbidity can be high, mortality is usually low

Answer 134

S. equi ## Footnote Abscessation of regional lymph nodes in the intermandibular area usually caused by infection with S. equi

Answer 135

• Cellular - hyaluronic acid capsule - M protein - IgG Fc binding proteins - peptidoglycan/teichoic acid •Extracellular -streptokinase, hyaluronidase Streptolysin S, DNAase Streptococcal Pyrogenic Exotoxins

Answer 136

Direct: contact with horse shedding bacterium Indirect: contact with contaminated environments (buckets, feed, walls, floor, grass, flies, water troughs)

Answer 137

(Signs appear 3-14 days after exposure) • - fever (39-39.5) (appears first) - purulent nasal discharge - depression, anorexia, dysphagia - moist cough - lymph node abscessation (submandibular, retropharyngeal) (within 2 weeks of initial signs)

Answer 138

* Disseminated infection (bastard strangles)---- CAN SPREAD TO ALL OF THE LYMPHNODES * Purpura hemorrhagica (immune complex mediated vasculitis)

Answer 139

(accumulation of purulent material in guttural pouch) Usually 2° to an upper respiratory infection Streptococcus equi – most common Spread from retropharyngeal lymph nodes into guttural pouches through lymphatic drainage & rupture into pouch

Answer 140

Guttural Pouch Chondroids * Chondroids = accumulation of soft or hard concretions in one or both guttural pouches * Associated with chronic empyema

Answer 141

• Incubatory (nasal shedding begins 4-7 days after exposure with or without clinically evident nasal discharge) • Clinical (shedding from affected sites; nasal, pharynx, lymph nodes, guttural pouch) • Convalescent (nasal shedding for up to 6 weeks after recovery) • Long term (5-7 months or more, mostly from guttural pouch)

Answer 142

* Infected animals usually recover after abscesses mature and rupture * Most (\>75%) animals have strong immunity following recovery

Answer 143

• Culture: swab, lavage fluid (nasal, pharynx, LN, GP) - 3 negatives at weekly intervals sufficient to release from quarantine (convalescent carriers) - test Guttural Pouch \> 30 days after recovery (for long-term carriers) • Serology: ELISA for antibodies to M protein • PCR: M protein gene target used to detect asymptomatic carriers; must confirm positive PCR by culture (detects live and dead bacteria)

Answer 144

Killed, IM S. equi vaccines (M protein enriched) used in pregnant mares and foals to maintain high levels of anti M protein opsonizing antibodies Live, IN S. equi vaccine used similarly to stimulate mucosal immunity as well as serum opsonizing antibodies (can complicate culture-based screening)

Answer 145

* Inhabit GI tract * Survive in environment * Nosocomial infections(systemic infections) • Persistent UTI • Vancomycin resistance pathogenicity island • In vivo resistance

Answer 146

* Listeria * Erysipelothrix * Bacillus * Corynebacterium * Rhodococcus * Nocardia * Actinomyces, Trueperella, Actinobaculum, Dermatophilus • Anaerobes(Clostridium) * Mycobacterium

Answer 147

**FOOD SAFETY PATHOGEN** Small, Gram positive, facultative anaerobic rods Isolated from many species of animals _Capable of growing at a wide range of temperature (4- 44o C)_- SUCH AS THE FRIDGE Ubiquitous in the environment, especially temperate zones Carried in the GI tract of animals Resistant to harsh environmental conditions **Sporadic disease in a variety of animals including man**

Answer 148

Listeria monocytogenes

Answer 149

Winter-spring disease of feedlot or housed ruminants. **Outbreaks typically occur after feeding poor-quality silage.** Economically important disease with seasonal occurrence (winter months) Ingestion or inhalation \>septicemia, abortion, and latent infection. \>localize in the intestinal wall, medulla oblongata, and placenta \>encephalitis via minute wounds in buccal mucosa. Poultry; septicemic listeriosis

Answer 150

• Invasive (bacterial directed invasion of epithelial cells)\>Enters blood stream * Facultative intracellular bacteria: persist in macropahges * Intracellular growth leads to cell death and focal microabscesses

Answer 151

Encephalitis: Most common presentation in ruminants(cattle, sheep, goat) Bacteria invade through oral mucosa travels along trigeminal nerve and have affinity for brainstem Abortion: Hematogenous spread to gravid uterus, organisms penetrate the placenta and spread to fetal liver resulting in focal hepatic necrosis Septicemia; common in monogastrics, Intracellular replication in macrophages, multifocal miliary abscess in spleen. Liver. Mainly occurs in neonates as a continuation of the fetal infection

Answer 152

* Internalin: adhesion, entry, phagocytosis * Listeriolysin O) (Hemolysin): required for intracellular multiplication Facilitate bacterial release from phagosomes • Act A: intracellular movement

Answer 153

brain stem

Answer 154

L. monocytogenes, THUS THEY CAN GET AWAY FROM THE IMMUNE SYSTEM

Answer 155

* Neurologic symptoms: Dullness, turning or twisting of head to one side, walking in circles (circling disease) * Unilateral facial nerve paralysis with drooping of eyelid and ear, drooling due to pharyngeal paralysis, Strabismus, nystagmus, hemiparesis, head pressing, decreased rumen motility * Purulent endophthalmitis, usually unilateral

Answer 156

Listeria there is also Unilateral signs of trigeminal and facial paralysis

Answer 157

Microabscesses and glial nodules infiltrated by neutrophils and gitter cells that may contain bacteria Acute vascular fibrinoid necrosis secondary to drainage into Virchow-Robin space Leptomeningitis and densely cellular perivascular cuffs composed of lymphocytes and histiocytes with fewer neutrophils and eosinophils Neuronal necrosis Cranial nerves may have intrafascicular and perineural accumulations of inflammatory cells (lymphocytes, macrophages, plasma cells and neutrophils)

Answer 158

CNS disease Ante-mortem: Presumptive diagnosis from symptoms Post-Mortem: No gross lesions, Histopathology, Culture of Brain stem Listeria enrichment culture Gram stained CSF sediment short intracellular and extracellular Gram positive bacteria Immunohistochemical staining Septicemia culture of liver and spleen

Answer 159

* Few gross lesions except for some congestion of meninges. * Microscopic lesions are confined primarily to the pons, medulla oblongata, and anterior spinal cord • In septicemic listeriosis, in calves that die when \<3 wk old, • Focal hepatic necrosis, and hemorrhagic gastroenteritis

Answer 160

* L monocytogenes is susceptible to penicillin (the drug of choice), ceftiofur, erythromycin, and trimethoprim/sulfonamide. * High doses are required because of the difficulty in achieving minimum bactericidal concentrations in the brain.

Answer 161

No vaccines; cell-mediated immunity important Avoid high risk foods poor quality silage, pH\>5.5 unpasteurized dairy products processed meats uncooked vegetables Minimize aerosol exposure Precautions for pregnant and immunosupressed animals

Answer 162

Small, non-sporeforming, Gram-positive rods A Gram-positive, non spore-forming, facultative anaerobic bacillus 26 serotypes identified and isolated from many species of wild and domestic mammals, birds, reptiles, amphibians, and from the surface slime of fish Swine are the most important reservoir of the organism. 30-50% of healthy swine harbor the organism in their tonsils or other lymphoid tissue, and occasionally shed the organisms in their feces **Swine from 3 months to 1 year of age and pregnant sows are most susceptible** Disease manifestations include: Septicemia, polyarthritis, and endocarditis

Answer 163

* Number of organisms exposed to •Route of exposure * Virulence of strain * Immune status of host going to be an exam question

Answer 164

Erysipelothrix rheusiopathiae – most frequent Most common in pigs and birds but also seen in many other species including man. (serotypes 1a, 1b and 2 common in pigs)

Answer 165

Erysipelothrix tonsillarum – less common Not virulent for pigs. Has been associated with disease in dogs.

Answer 166

• Transmission is primarily oral, with infection of palatine tonsils or GALT, * Organism may enter through skin abrasions * Neuraminidase; Adherence to endothelial cells * Heat labile capsule resists phagocytosis by neutrophils

Answer 167

Erysipelothrix rhomboid lesions

Answer 168

• Acute - septicemia, common (pigs, birds, others) - abortion, rare (pigs) - cutaneous cellulitis/urticaria, occasional (pigs, birds, man) • Subacute - vegetative (valvular) endocarditis, occasional (pigs, birds, man, others) • Chronic - arthritis , common (pigs, birds)

Answer 169

common in Erysipelothrix

Answer 170

* Diagnosis: culture * Treatment: antimicrobial treatment of acute infections (penicillin, tetracycline) • Control: treat and isolate infected animals cull chronically affected animals good hygiene practices vaccination (pigs, turkeys) (live attenuated + bacterin) (surface proteins, eg. 60 kd, Spa, 19kd thought to be important protective antigens)

Answer 171

Staphylococcus pseudintermedius

Answer 172

Staph pseduintermedius

Answer 173

Streptococcus- chain of cocci

Answer 174

Staphylococcus

Answer 175

A. Binding indiscriminately to the T cell receptor and class II MHC Molecule because it's a superantigen; when it binds it releases lots of cytokines

Answer 176

Large Gram-positive rods Endospore-forming * Thick peptidoglycan layer * Teichoic and lipo-teichoic acids * No outer membrane * Rapidly growing bacteria * (On Gram+ selective and non-selective media) * No growth on MacConkey’s agar (MacConkey agar is selective for Gram negatives) • Aerobic or facultative anaerobes • Variation in hemolytic activity • Saprophytes identified only to Genus level

Answer 177

* Bacillus anthracis – obligate mammalian pathogen * Bacillus cereus – rare cause of opportunistic infections and food poisoning in mammals * Few Insect pathogens eg. Bacillus thuringiensis Most species are soil saprophytes

Answer 178

Koch’s postulates were developed using Anthrax bacilli Aerobic, non-motile, large, square-end Gm+ rods in chains Non-hemolytic (rough/ground glass/Medusa head colonies) Mature endospores do not bulge from cell

Answer 179

Medusa head colonies as seen in Bacillus antracis

Answer 180

Cell associated **Capsule (Polymers of D glutamic acid)** Extracellular Anthrax toxin (3 proteins: edema factor, lethal factor and protective antigen) Both virulence factors encoded by plasmids Both are required for virulence

Answer 181

• produced only in vivo (capsule biosynthesis operon)- **ONLY IN THE BODY OF THE ANIMAL** transcriptionally upregulated by CO2/bicarbonate signal) * polymers of D-glutamic acid * encoded on a plasmid • anti-phagocytic

Answer 182

Bacillus anthracis Capsule stain as a pink shadow with Polychromatic methylene Blue

Answer 183

(three separate(Tripartite toxin), proteins encoded on one plasmid) Edema factor – calmodulin-dependent adenylate cyclase (inhibits neutrophil function) Lethal factor – zinc metalloprotease (cell death, hypoxia-induced tissue injury/shock) Protective antigen – cell binding factor (translocation into cell) Together the components of anthrax toxin cause increased vascular permeability and cell necrosis

Answer 184

• Dependent on susceptible animals for replication (limited period of growth: bacterium kills host or host kills bacterium) • Dependent on endospores for survival in soil (exposure of carcass to oxygen increases sporulation) • Ecological cycles of infection (sporulation and germination have specific requirements)

Answer 185

* History: site (general) of previous anthrax deaths * Flooding: soil rearrangement brings endospores to surface, endospore concentration is increased in standing surface water as it recedes • Soil conditions: Alkaline (pH\>6), rich in calcium (calcareous) and nitrogen (decaying vegetation, etc.): favors endospore survival • Warm temperature (\>60-80 degree daily low temp): during drought conditions animals forage closer to the ground increasing chances of soil ingestion and mechanical injury to GI mucosa

Answer 186

Exposure to endospores: Most common Endospores germinate within phagolysosomes of macrophage Intracellular survival factors allow growth initiation and a phospholipase mediates escape from the phagocytic cell Capsule and edema factor inhibit phagocytosis of vegetative cells Vegetative cells grow rapidly in the body Complete anthrax toxin causes cell death and affects vascular permeability

Answer 187

* Per acute septicemia – ruminants (cattle Sheep) •Acute septicemia – horses * Pulmonary – man (wool sorter’s disease) •Pharyngeal – pigs, dogs •Intestinal – man, pigs, horse •Cutaneous – man (malignant carbuncle)

Answer 188

rapidly fatal disease high fever, bleeding from orifices, shock, respiratory distress

Answer 189

Dark, unclotted blood, Incomplete rigor mortis Splenomegaly: large, “current-jelly” spleen, widespread edema bacteremia(80% of bacteria in blood at time of death)

Answer 190

Blood smear examination: for presumptive diagnosis Aerobic Culture and PCR from Blood Fluorescent antibody staining DO NOT conduct a Field Necropsy if you have Anthrax in your DD list Call the state/ Federal officials

Answer 191

Hypertrophy of the spleen

Answer 192

Sample Collection Blood and aqueous humor for culture, Spleen If you happened to open up the carcass and observe splenomegaly Blood and organ smears stained with Polychromatic Methylene Blue (McFadyean’s methylene blue) Blue staining organisms with a pink capsule Chains of encapsulated, gram positive, non- spore forming rods, non-motile, roughly rectangular rods with square ends in Gram stains

Answer 193

Treatment: (vegetative cells only) antimicrobials effective if given early localized forms may resolve without treatment penicillin, tetracycline, doxycycline, ciprofloxacin Control: vaccinate healthy animals (endemic/high risk areas only)

Answer 194

Quarantine herd (for at least 30 days following last death) Use personal protective equipment when handling animals and contaminated materials (eg. gloves, coveralls, etc) Treat all animals in herd with long-acting antimicrobials (eg. Oxytetracycline ) Move herd from field/pasture/range Examine animals daily (treat those with increased temp.) Vaccinate8-12daysafterantibiotictreatment Properly dispose of carcasses Disinfect contaminated materials

Answer 195

incineration or deep burial (\>6.5 ft) under layer of quicklime (anhydrous calcium oxide)

Answer 196

Cutaneous anthrax Complications include subcutaneous edema and septicemia The case fatality rate is 10-20% Gastrointestinal anthrax: Follows consumption of contaminated meat Pharyngeal lesions, sore throat and dysphagia, Regional lymphadenopathy, Inappetence, nausea, vomiting blood and bloody diarrhea , Massive septicemia and toxemia, Fatality rate 25-60% Pulmonary or inhalation anthrax Produce pulmonary edema, hemorrhagic pneumonia, and sometimes meningitis Mortality approaches 100%, Sudden onset of acute symptoms, Hypotension, edema and fatal shockLength of incubation period inversely related to dose Spores may remain dormant until engulfed by pulmonary alveolar macrophages

Answer 197

Listeria monocytogenes

Answer 198

D. Hepatic necrosis is in YOUNG ANIMALS and monogastric animals

Answer 199

FALSE- the capsule is polylucemic acid

Answer 200

capsule of anthrax bacilli

Answer 201

FALSE- Anthrax is an infectious disease-- this is why there are sporative outbreaks

Answer 202

Gram-positive, pleomorphic non-spore forming, non-motile, rods Facultative anaerobe, catalase positive Diverse genus, many species found in soil and other environmental sources Animal associated species are commensals on skin and mucous membranes Environmental survival of lipophilic species may be prolonged Lipophilic spp.: Facultative Intracellular bacteria Pyogranulomatous C. pseudotuberculosis, C. urealyticum Non-lipophilic spp pyogenic, toxic C. renale group C. diphtheria Most species recovered from animals are not considered pathogenic **HAS MYCLOIC ACID**

Answer 203

Corynebacterium renale Group (C. renale, C. cystiditis, C. pilosum) Disease of adult cows Reservoir: clinically normal carrier cows Risk factors: trauma to bladder and urethra during parturition Transmission: contaminated bedding, venereal transmission non-sterile OB instruments

Answer 204

Persistent temperature increase (39.5) Loss of appetite and weight loss Painful urination and increased frequency **Ammoniac odor of urine** Acute abdominal pain (colic) Decreased rumen contractions Decreased milk production

Answer 205

Multifocal abscesses in renal cortex, medulla, pelvis Enlarged renal lymph nodes Uremia Diagnosis: culture (urine or renal tissues)

Answer 206

Caseous lymphadenitis in sheep and goats * Corynebacterium pseudotuberculosis * C. pseudotuberculosis is a gram-positive, facultative, intracellular coccobacillus. • The disease is characterized by abscess formation in or near major peripheral lymph nodes (external form- goats) or within internal organs and lymph nodes (internal form- Sheep). Pigeon fever in horses(Colorado strangles”, “dry-land distemper”) Nitrate-reducing biotype of C. pseudotuberculosis Ulcerative lymphangitis of lower extremities Cattle can also get infected Abscesses in the pectoral region ventral abdomen Western and Midwestern states Enter through skin abrasions arthropod vectors such as stable flies, horn flies, and house flies, or contaminated fomites or soil.

Answer 207

Exotoxin phospholipase D damaging endothelial cells and increasing vascular permeability. External lipid coat that provides protection from hydrolytic enzymes in host phagocytes. Entry through skin and mucous membrane\>Travel to lymphnodes and Viscera\>Replication of bacteria occurs in the phagocytes\>process of bacterial replication, and inflammation\>formation of abscesses distinctive lamellated "onion skin" appearance. Disease severity increases with age

Answer 208

Corynebacterium tuberulosis- ## Footnote **THIS IS CONTAGIOUS**

Answer 209

Caseous Lymphadenitis (C.pseudotuberculosis)

Answer 210

Caseous necrosis of lymph nodes is the predominant feature. The initial lymph node lesion begins as lymphadenitis with the formation of multiple microscopic abscesses in the cortex; eosinophils may predominate initially. Microabscesses rapidly coalesce, forming areas of caseation. Abscesses become rapidly encapsulated by fibrous connective tissue, and the lymph node enlarges.

Answer 211

Culture of purulent materials

Answer 212

A synergistic hemolysin inhibition (SHI) test that detects antibodies to the phospholipase D exotoxin Positive titers indicate past resolved infections, recent exposure, recent vaccination, or active lesions Interpretation of titers??? False-negative results early in the infection and with chronic, walled- off abscesses. Colostral antibodies in young animals

Answer 213

1. could have the infection now 2. exposure 3. previous infection YOU CAN NOT TAKE A POSITIVE RESPONSE AS A POSITIVE TEST RESULT.

Answer 214

Owner education Not considered a “curable” disease. Animals with genetic or emotional value are treated Treatment options have included lancing and draining, surgical excision, formalin injection of lesions, systemic antibiotics, and intralesional antibiotics. (Extra label use) Penicillin, Rifampin, Tulathromycin,

Answer 215

* Biosecurity practices * Culling of infected animals * Hygiene and management practices * Vaccines are available but strictly adhere to the label • Purchase animals from negative herds

Answer 216

Murine pseudotuberculosis Lung: Suppurative pneumonia Kidney, liver, heart: Similar nodular lesions Joints: arthritic lesions of pedal extremities subcuticular abscesses Lymph nodes: Lymphoid hyperplasia of regional nodes

Answer 217

Dermatitis, Hyperkeratosis in mice

Answer 218

Capsule **virulence associated proteins (VAPs)** (encoded on large plasmids) (promotes survival in non-activated macrophage) Mycolic acid, teichoic acid/peptidoglycan cholesterol oxidase (equi factor) phospholipase C

Answer 219

(rhodo, “rose” or red-colored) Gram-positive rods or coccobacilli, non-spore forming Weakly acid-fast (modified stain) Aerobic, catalase-positive, non-motile Growth in 48-72 hrs on blood agar No growth on MacConkey’s agar Facultative intracellular pathogen Unique lipid-rich cell envelope structures rich in mycolic acid Promotes intra-macrophage survival and granuloma formation One of the main cause of Foal Pneumonia

Answer 220

Habitat is soil; however, it appears that **virulence is maintained in horses**. Over a long period of time, soil isolates may lose the virulence associated plasmids Non-pathogenic strains of R. equi and other species of Rhodococcus are soil saprophytes Found infrequently as an opportunistic pathogen in other animals (isolates from non-equine hosts usually lack virulence associated proteins)

Answer 221

Rhodococcus equi is the most serious cause of pneumonia in foals 1–4 month old. Significant economic consequences because of mortality, prolonged treatment, surveillance programs for early detection, and relatively expensive prophylactic strategies. Clinical disease is rare in horses \>8 mo old. pulmonary infection probably originates within the first week of life.

Answer 222

Lung: Multiple 1-100 mm diameter, coalescing, firm, caseonecrotic foci predominately in the crainioventral lung lobes Gastrointestinal tract: Ulcerative enterocolitis often based over Peyer’s patches in the ileum and irregular well defined ulcers in the large intestine occur in more than 50% of foals with pneumonia. Bronchial and mesenteric lymph nodes: Swollen and edematous often with pyogranulomatous lymphadenitis Bone: Osteomyelitis

Answer 223

Cattle: Metritis, lymphadenitis and pneumonia in calves Sheep: Caseous bronchial lymphadenitis Goats: Pyogranulomatous lesions in the liver and lungs; osteomyelitis of the vertebra and skull; fibrinous enterocolitis Pigs: Tuberculosis-like lesions in submaxillary and cervical lymph nodes Cats: Pyogranulomatous skin lesions Humans: Zoonotic in immunocompromised individuals

Answer 224

R. equi ddx: could also be herpes

Answer 225

Evaluate the entire premise (needs for each farm will vary) Screen for early detection of disease or infection elevated plasma fibrinogen visual inspection (clinical signs often absent early) (increased respiratory effort, lethargy, polyarthritis) rectal temp. 2x/day physical exam 2x /week CBC (increased WBC) thoracic radiographs/ultrasound (foals 1-3 months-old) Serology tests are available but are not reliable for screening or diagnosis

Answer 226

Definitive diagnosis = Culture or PCR (for VAP A/B) on transtracheal aspirate (or specimen from other lesions) PLUS cytologic evidence of sepsis Culture of feces not reliable for diagnosis of granulomatous enterocolitis (However, organisms may be shed f virulent organisms) Serology not reliable

Answer 227

Treatment prolonged (7 days to \>3 weeks) **because it's an intercelluar pathogen**, expensive, may have adverse effects and is variably successful Standard empirical treatment = Combination of macrolide (erythromycin or clarithromycin) and rifampin (they exhibit synergy in vitro) • Resistance to macrolides has been reported • Hyperimmune plasma and NSAID use is variable

Answer 228

Young foals (\<2weeks) are more susceptible; it is hypothesized that exposure may occur very early in life Hyperimmune plasma can prevent pneumonia (given on 1st or 2nd, 3rd and 4th day of life) (protective components unknown – cellular immunity important) Course of azithromycin chemoprophylaxis treatment given shortly after birth also has promise Vaccination of mares or colostrum from immunized mares have not been effective A combination of early detection, treatment and environmental management is needed Untreated or uncontrolled disease can have negative effects on an individual animal’s future performance and a farm’s reputation

Answer 229

* Nocardia: pleomorphic, gram-positive, facultative intracellular bacterium, nonmotile and non-spore-forming * In Gram stained smears, it appears as rods, cocci, or cocobacilli forms with characteristic long or branching filaments and a tendency to fragment into rods and cocci. * Pathogenic Nocardia spp are strictly aerobic, growing over a wide temperature range * Ubiquitous in the soil and water Nocardiosis is more common in dogs than in cats.

Answer 230

the most commonly isolated species in dogs and cats Nocardiosis is an opportunistic, noncontagious, pyogranulomatous to suppurative disease of domestic animals, wildlife, and people. Mastitis, pneumonia, abscesses, and cutaneous/subcutaneous lesions Livestock and companion animals.

Answer 231

Cutaneous nocardiosis in cattle, called “bovine farcy”, is caused by N. asteroides (formerly called N. farcinica); lesions are typically associated with lymphangitis and lymphadenitis

Answer 232

has been associated with abortion in horses, cattle, sheep, and swine, often with no other signs in the dam. Causes granulomatous mastitis in cattle and small ruminants

Answer 233

n horses, N. asteroides and N. braziliensis can cause fibrinopurulent pneumonia and pyothorax with sulfur granules

Answer 234

In humans, most patients with N.asteroides infections have defects with T- cell mediated immunity, often associated with prolonged steroid use, HIV infection, or diabetes mellitus

Answer 235

Not usually pathogenic for immunocompetent individuals • Causes pyogranulomatous infections (thorax, skin, mammary gland, systemic) Feline pyothorax

Answer 236

mass spec is what we use

Answer 237

Nocardia mastitis

Answer 238

* Diagnosis: culture, acid-fast stain, ID can predict susceptibility * Treatment: susceptibility varies with species Best empirical choice for systemic, life-threatening infection is a combination of an aminoglycoside (eg. amikacin) and a carbapenem (eg. imipenem). Single treatment with trimethoprim/sulfa is effective for many species. •Control: difficult (Disease is sporadic)

Answer 239

Corynebacterium psuedotuberculosis

Answer 240

FALSE- one titer is not diagnostic; it can be positive due to exposure or previously having the disease

Answer 241

FALSE- It is NOT obligate- it can be extracelluar as well as intracellular

Answer 242

Amphotericin Chloramphenicol Tetracycline Erythromycin Neomycin Streptomycin Gentamicin

Answer 243

Many actinomycetes are soil dwelling environmental saprophytes; Many genera produce cell fragments that resemble fungal spores (can be released into the air causing allergic respiratory diseases **NO MYCOLIC ACID** **Gram positive non-sporeforming rod May show filamentous branching Non-acid fast** **Virulence factors are not well-described** **Habitat of pathogenic species is mucosa of the oropharynx (some** **species host restricted)** **Facultative anaerobic & anaerobic spp. some are capnophilic** **Most are catalase negative** **Colonies vary, usually small slow-growing** **“molar tooth-like”**

Answer 244

Frequently associated with pyogenic infections in livestock, Eg. Trueperella pyogenes (formerly Corynebacterium, Actinomyces, and Arcanobacterium pyogenes)

Answer 245

Chronic, progressive, pyogranulomatous disease **Polymicrobial infection** with oropharyngeal flora Initiated by disruption of mucosal barrier, often involving plant material (foreign bodies, grass awns), bite wounds, oral trauma Spread by direct extension (lymphogenous and hematogenous spread also possible) Chronic infections may cause bone lysis Common in active outdoor animals (eg. hunting breeds) • Actinomyces sp. grow as colonies in center of lesion (granule-like consistency) Pyogenic response surrounding colony often forms draining tracts Outer zone of lesion has granulomatous characteristics (chronic infection)

Answer 246

Cattle: Actinomyces bovis (lumpy jaw) Pyogranulomatous osteomyelitis Lumpy jaw is a localized, chronic, progressive, granulomatous abscess that most frequently involves the mandible, the maxillae, or other bony tissues in the head. Introduced to underlying soft tissue via penetrating wounds of the oral mucosa from wire or coarse hay or sticks. Involvement of adjacent bone frequently results in facial distortion, loose teeth (making chewing difficult), and dyspnea from swelling into the nasal cavity. A Gram stain of purulent material will reveal gram-positive, club- shaped rods and filaments (sulfur granules).

Answer 247

Foxtail (grass awns)

Answer 248

• Diagnosis: - Culture / microscopic examination of granules Must request aerobic and anaerobic culture( Actinomyces can be aerobic anaerobic or capnophilic) • Treatment: - susceptible to penicillin G, iodides - may require long term treatment (3-12 months) with high dose penicillin - surgical excision of foreign bodies/circumscribed lesions • Control: - minimize risk of mechanical injury, remove foreign bodies

Answer 249

Filamentous, branching Divides in two planes to give “tram-track” appearance and produce coccoid fragments which become motile zoospores Zoospores have chemotaxis for CO2 Aerobic, catalase positive Habitat is skin of infected animals Dermatophilosis can affect cattle, sheep, goats, horses, and less frequently pigs, dogs, and cats.

Answer 250

Motile zoospores are attracted to moist, damaged skin * Cause epidermal abscesses with hyperkeratosis * Virulence properties include, chemotaxis of zoospore, keratinolytic activity and survival of zoospores in dry scab- like crusts

Answer 251

D. congolensis

Answer 252

Rain Scald- D. Congolensis

Answer 253

D. congolensis or strawberry foot rot in cattle

Answer 254

* Diagnosis: * microscopic demonstration of organisms in scabs • Treatment: systemic antibiotic treatment (susceptible to penicillin G and Tetracycline) Control: treat and isolate infected individuals eliminate predisposing factors and vectors dry shelter- tick control, brush removal

Answer 255

D. congolensis- on cows in St. Kitts

Answer 256

Pleomorphic, facultative anaerobe, non-spore forming, non-motile, non-capsulated, capnophilic Causes suppurative infections in ruminant and swine Diseases prevalence is sporadic and governed by precipitating stress or trauma Found on mucous membranes Most infections are probably endogenous **COMES FROM THE COW'S BODY- COMES OUT WHEN THEIR IS AN IMMUNITY PROBLEM WITH THE COW**

Answer 257

nvolved in most purulent infection of traumatic or opportunistic origin May be local, regional, or metastatic Common locations include: The lung, pericardium, endocardium, pleura, peritoneum, liver, joints, uterus, renal cortex, brain, bones, and subcutaneous tissues Causes abortion and mastitis in cattle Summer mastitis is a communicable disease among pastured daily cattle during the dry period

Answer 258

Trueperella pyogenes

Answer 259

Anaerobic bacteria • Commensal diphteroid organism in prepucial mucosa of boars * Sexually transmitted pathogen * Causes cystitis and pyelonephritis 3-4 weeks post-coitus • Death as a consequence of renal failure * Pathogenesis similar as bovine pyelonephritis (C. renale) • UREASE as virulent factor

Answer 260

is a communicable disease among pastured daily cattle during the dry period Trueperella pyogenes in Cattle

Answer 261

Anthrax and Clostridium

Answer 262

Clostridium piliforme A Gram negative Clostridium which causes Tyzzers disease in laboratory animals

Answer 263

Large, endospore-forming, Gram-positive rods Except for Clostridium piliforme A Gram negative Clostridium which causes Tyzzers disease in laboratory animals

Answer 264

3 categories of Clostridium: * Neurotoxic * Histotoxic and invasive •Enteric/ Enterotoxigenic Widespread distribution in soil and intestines of animals Endospore amplification may occur in well-defined geographical locations (requires anaerobic conditions)

Answer 265

All pathogenic Clostridia produce one or more bacterial protein toxins or extracellular enzymes. Growth of Clostridia in the body requires anaerobic conditions: Necrosis is both a common predisposing factor for and host response to clostridial infection Necrosis provides an initial opportunity for Clostridium to grow Necrosis is the host response to many clostridial toxins Necrosis facilitates the rapid spread of infection through the body

Answer 266

* Anaerobic Gram positive rod * Cause tetanus * Terminal endospores * Widespread in soil and feces * Grow in contaminated wounds * Produce a potent neurotoxin (tetanospasmin) * AB toxin with zinc endopeptidase activity * Wound infection by Clostridium tetani\>Toxin produced in the wounds\>Toxin enters nearest motor nerves by receptor mediated endocytosis \>Retrograde transport along axons of peripheral motor nerves and spinal cord or via blood stream, enters neuromuscular endings of many motor nerves\>Prevents release of neurotransmitters, glycine and GABA \>**Causes spastic paralysis**

Answer 267

Clostridium tetani; called "wooden horse" in horses

Answer 268

* History of recent wound and Clinical signs * Culture often unrewarding * Demonstration of toxin in serum or tissue difficult, often unrewarding, and testing not widely available * Serology not useful

Answer 269

Antitoxin (to neutralize unbound toxin) Anti-tetanus equine serum given IV or IM; anaphylaxis possible Antimicrobial treatment (to stop production of toxin) Surgical debridement of wounds; hyperbaric oxygen (to stop production of toxin) Supportive care – reduce external stimuli, sedatives, muscle relaxants

Answer 270

Toxoid immunization (man, horses, small ruminants) Post exposure prophylaxis (toxoid booster in man, horses) Prompt wound management (vaccinated and unvaccinated animals) Rational Antimicrobial therapy • Aseptic techniques while surgery, Proper sterilization of surgical instruments

Answer 271

* Diverse group of organism (Toxin types A-G) • Toxin type/ Species affinity * Botulism * Botulinum neurotoxin * Food intoxication (food poisoning) * Toxin absorbed and distributed in bloodstream * Occasional toxico-infectious forms – wounds, intestinal • (infant botulism/shaker foal) * Inhibits neurotransmitter release (acetylcholine) Preformed toxins in a variety of sources including decaying vegetable matter (e.g., grass, hay, haylage, grain, spoiled silage), meat and fish, carcasses, invertebrates and contaminated * Carnivores are usually fed the toxins in contaminated meat or fish, or ingest the toxins in carcasses or decaying, high protein garbage. * Cattle in phosphorus-deficient areas may develop pica and chew bones and scraps of attached meat; * “a gram of dried flesh may have enough botulinum toxin to kill a cow”

Answer 272

• Symmetrical flaccid paralysis of muscles Early symptoms in humans usually involve cranial nerve functions (double vision, dysphagia, speech dysfunction, etc.) Early symptoms in other mammals usually involve hind limb paralysis, recumbence Skeletal muscle paralysis can lead to respiratory failure

Answer 273

C. botulinum

Answer 274

limberneck

Answer 275

Demonstration of toxin in serum of animal Demonstration of toxin in food/stomach contents (mouse bioassay/neutralization test- gold standard) MALDI TOF

Answer 276

IV or IM antitoxin (affects unbound toxin only) Only of use if animal is still actively absorbing toxin. Once toxin enters blood stream it is quickly bound to receptors Therapeutic drugs to enhance cholinergic neurotransmitter (acetylcholine) release Supportive care (fluids, respiratory maintenance, feeding/elimination functions)

Answer 277

Toxoid immunization in high risk animals • Avoid feeding suspect foodstuff | (farmed mink, susceptible exhibit animals) Occupational protection in man discontinued, 2011 Most animals not routinely vaccinated)

Answer 278

aquatic birds because they eat maggots

Answer 279

C. chauvoei C.septicum C. novyi Less potent Toxins Invasive infections Myositis

Answer 280

Wounds resulting from mechanical injury or vascular compromise result in anaerobic environments for deposited endospores to germinate and grow Toxins elaborated during growth cause more tissue destruction. Fermentation of muscle glycogen results in gas accumulation (hydrogen/methane). Metabolic end products (organic acids, amines) often have distinctive smells. Mechanically deposited endospores or that leave the intestinal tract may remain dormant in the body for extended periods **endospores stay dorminate** **necrosis and lots of gas production** **racid smell**

Answer 281

necrotic myositis **C. chauvoei** C. perfringens C. septicum C. novyi ndospores (widely distributed in soil/GI tract) Rapid growth in anaerobic conditions fermentative/proteolytic activities Exotoxins/extracellular enzymes

Answer 282

C. novyi (A, B , C)

Answer 283

C. chauvoei Acute, febrile, highly fatal disease of cattle and sheep Emphysematous swelling, commonly affecting heavy muscles. Endogenous infections in cattle well-nourished young cattle Wound infections shearing cuts, docking, crutching, or castration in sheep * 100% fatality * Characteristic edematous and crepitant swellings develop in the hip, shoulder, chest, back, neck * Myocardium and diaphragm are affected

Answer 284

C. septicum

Answer 285

C. novyi type B -Black disease – Necrotic hepatitis • Spores in the intestine and reach liver remail dormant in Kupffer cells\> traumatic damage by **liver fluke**\> anaerobic conditions\> germination of spores

Answer 286

* Cellulitis, necrotic myositis * Often moves along fascial planes * Lesions appear hemorrhagic (edematous or dry) •May detect crepitus * Sudden death common •Clinical signs may include: fever, anorexia, depression, lameness

Answer 287

C. septicum • Fatal toxemia affects all species and ages of animals Dormant spores present in muscle tissues. Risk factors include IM injections in horses; shearing, docking, and lambing in sheep; and traumatic parturition and castration in cattle. Local exotoxins cause excessive inflammation, resulting in severe edema, necrosis, and gangrene. C septicum also causes braxy in sheep, a highly fatal infection characterized by toxemia and inflammation of the abomasal wall.

Answer 288

Diagnosis: Direct Fluorescent antibody staining test (DFA) The most practical and faster option Available for C. chauvoei, C. septicum, C. novyi Anaerobic culture not very rewarding and time consuming

Answer 289

Treatment: antimicrobial treatment (penicillin) (only effective if given early) hyperbaric oxygen surgical debridement/amputation • Control: routine vaccination of farm animals with multicomponent bacterin/toxoids

Answer 290

* C. perfringens * C. difficile * C. spiroforme necrotic/hemorrhagic enteritis, necrotic hepatitis enterotoxemia

Answer 291

Four Major Toxins used for toxin biotyping (Types A-E based on the presence of Alpha, Beta, Iota, Epsilon) Necrotizing haemorrhagic enteritis in multiple species of animals Enterotoxaemia in cattle pigs horse sheep goat Type C in piglets * TYPE D ENTEROTOXEMIA * (Pulpy kidney disease, Overeating disease) http://www.merckvetmanual.com/mvm/generalized\_conditions/ clostridial\_diseases/enterotoxemias.html

Answer 292

C. perfringens

Answer 293

A fluid-distended intestine with hemorrhagic petechiae on the serosal surface. Edema and malacia can be detected in the basal ganglia and cerebellum of lambs. **(focal encephalomalacia**) Rapid postmortem autolysis of the kidneys (pulpy kidney disease)

Answer 294

C. perfringens Type D enterotoxemia

Answer 295

Rapid postmortem autolysis of the kidneys C. perfringens Type D enterotoxemia

Answer 296

Microscopic appearance/relative number Culture (determine toxin genotype of isolates) Toxin detection in intestinal contents Biological assay (mouse neutralization) Serological tests for toxin antigen ( cpe ELISA) * Treatment: * hyperimmune serum may be of value (if available and given early) * antimicrobial therapy not generally effective for GI diseases * Control: routine immunization of farm animals with toxoid/bacterins avoid sudden diet changes or stresses that might alter GI flora or damage GI mucosa

Answer 297

Affects colon and cecum of man, horse, pig, dog, cat, laboratory rodents, others Risk factors include recent antibiotic use, increased-age, hospitalization Neonates are resistant (may harbor toxigenic strains/toxins) * Endospores widespread (low numbers in normal intestine) * Most disease results from disruption of normal flora, proliferation of C. difficile, and toxin production * Nosocomial transmission has also been suggested

Answer 298

FALSE- it doesn't have mycolic acid

Answer 299

Aerboic and anerobic culture- absyess submit both!

Answer 300

B Corynebacterium renele causes pyelonepritis in cattle

Answer 301

when the normal flora of the GI tract is disturbed- these cause Pseudomembraneous colitis which causes

Answer 302

Tox A – enterotoxin - fluid loss - affect G proteins Tox B – cytotoxin (in vitro) - similar mechanism of action - destroys cells more rapidly - acts synergistically with Tox A Most strains produce both toxins A&B A few strains produce Tox B only

Answer 303

• Culture Obligate anaerobe Vegetative cells sensitive to handling/treatment Selective media enhances germination of spores • Direct toxin detection Tissue culture assay (tox B) with specific antibody neutralization Toxin antigen detection (ELISA, latex aggn.- tox A or toxA/B)

Answer 304

* Supportive electrolytes and fluids * Stop antibiotics * Clindamycin should not be used in horses * (antimicrobials may be needed in severe cases) * Probiotics (Lactobacillus, Saccharomyces replaces flora) • Avoid anti-diarrheals accumulates toxin) * Toxin adsorbent (adsorbs meds also)

Answer 305

Enterotoxemia an explosive diarrheal disease Primarily of rabbits 4–8 wk old. It Necropsy reveals the typical lesions of enterotoxemia, ie, a fluid-distended intestine with hemorrhagic petechiae on the serosal surface. • The primary causative agent is Clostridium spiroforme (commensal) which produces an **iota toxin.** • lincomycin, clindamycin, and erythromycin induce Clostridium-related (eg, C difficile and C. spiroforme) enterotoxemia due to their selective effect on normal gram- positive bacteria, they are contraindicated in rabbits.

Answer 306

Clostridium piliforme- Tyzzer’s Disease • Acute, fatal diarrheal disease of lab animals with associated focal liver necrosis • C. piliforme does not grow in cell-free media; seen in bundles in hepatocytes (may also infect myocardium, smooth muscle, enterocytes) • Disease also reported in other mammals (eg. dogs, cats, foals, primates) **ONLY GRAM NEGATIVE CLOSTRIDIUM** **DX POST MORTEM**

Answer 307

Gram Positive Cocci: Peptostreptococcus, Sarcina Rods: Propionibacterium, Bifidobacterium, Actinobaculum (Lactobacillus, Actinomyces) • Gram Negative Cocci: Veillonella, Ruminococcus Rods: Fusobacterium, Bacteroides, Dichelobacter Porphyromonas, Prevotella Spirochaetes: Treponema, Brachyspira, unclassified * Commensals on mucous membranes and skin * Many require enriched media with vitamin K, hemin and other growth factors Many grow more slowly than common aerobic and facultative anaerobic bacteria Clinical identification is based on morphology, antimicrobial susceptibility pattern, biochemical tests, products of fermentation, and molecular testing **IN GIT**

Answer 308

* Not well characterized in all species – adhesins, extracellular enzymes, LPS shown to be important for some example: * Fusobacterium necrophorum – leukotoxin Dichelobacter nodosus – fimbriae, proteases • Catalase and superoxide dismutase Protect some from oxygen toxicity (aerotolerance) • Synergistic activities – tissue damaging factors that establish niche for second organism

Answer 309

Most are of endogenous origin Require anaerobic environment/ devitalized tissue for growth Usually localized, often oral/GI tract- associated, spread by direct extension (can cause transient bacteremia & secondary localization, especially on damaged heart valves) Mixed infections (polymicrobial) Synergistic relationships are common

Answer 310

* Foul smelling discharges * Gas in tissues or discharges * Necrotic tissue, abscesses * Pyogranulomatous lesions with granules * Infections near or on mucous membranes * Infections not responding to aminoglycosides • Disease in the absence of significant growth in aerobic cultures

Answer 311

leukotoxin- kills leukocytes

Answer 312

Fusobacterium necrophorum (multispecies, rumen) (foot rot, hepatic abscesses, calf diphtheria,) * Dichelobacter nodosus (foot rot in sheep) • Bacteroides fragilis * Porphyromonas spp (most produce black iron porphyrin pigments) • Prevotella spp (some produce black iron porphyrin pigments)

Answer 313

Liver abscess Foot Rot extensive necrosis and keratinolysis in severe cases

Answer 314

• Control: - keep feet dry, avoid mechanical injury - parasite control, routine immunizations, good nutrition, dental prophylaxis, etc. - vaccines: sheep & cattle (Fusobacterium necrophorum) sheep (Dichelobacter nodosus

Answer 315

anerobic infection

Answer 316

* Diagnosis: * Culture, (PCR?) • Treatment: - remove necrotic tissue, oxygenate, antiseptic foot baths - antimicrobials - penicillin, metronidazole, clindamycin, chloramphenicol, doxycycline (aminoglycosides, sulfonamides not effective)

Answer 317

Identification of anaerobes requires specialized methods and is often incomplete • Current methods include: - Biochemical test kits - 16S rRNA gene sequencing - MALDI-TOF-MS • Susceptibility testing specialized and only standardized for a few genera (eg. Bacteroides and Clostridium)