Exam 1 Flashcards by Sam Johnson

Gram+ coccobacillus, slightly larger than Streptococcus -suppurative bronchopneumonia w/ abscesses in lungs and hilar lymph nodes of foals -chronic pyogranulomatous inflammation -infection largely w/in macrophages/monocytes

Rhodococcus equi

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What do these have activity against? ß-Lactams Chloramphenicol Macrolides Metronidazole Tetracyclines Sulfonamides

Gram Positive Anaerobes and Gram Negative Anaerobes

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A clear zone around a colony on a blood agar plate. Most are pathogenic strains.

Streptococcus Beta Hemolysis

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Presence of microorganisms and/or their products (toxins) in the circulating blood

Septicemia, septic, sepsis

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Histotoxic clostridia 1. Big head in rams? 2. Black disease (infectious necrotic hepatitis)? 3. Bacillary hemoglobinuria (redwater)?

C. novyi Type A 2. C. novyi Type B 3. C. haemolyticum (C. novyi Type D)

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Bactericidal by interfering w/ protein synthesis -misreading of mRNA -uptake requires oxygen-dependent active transport -serious GRAM NEGATIVE infections, limited G+ activity -*Obligate anaerobes are resistant -poor cell wall penetration, used in combo w/ ß-lactam -Acquired resistance=plasmid mediated enzymatic modification w/ incomplete cross-resistance

Aminoglycosides

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-Natural habitat is soil, esp. contaminated by animal feces, transient in intestines -endospores enter traumatized tissue or wounds (castration, docking, umbilicus, parturition) -travels in neurons to CNS, suppresses NT release from inhibitory interneurons–spastic paralysis *single serotype

Clostridium tetani

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Clindamycin, lincomycin, pirlimycin -bacteriostatic by inhibiting protein synthesis -active against G+ aerobes, mycoplasma and anaerobes -wipe out anaerobes in gut flora causing GI issues

Lincosamides

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What kind of organisms are the majority of microbiota?

Obligate anaerobes (40-80% Gram+, 40-60% Gram-)

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“Lumpy Jaw” -chronic progressive, cattle, granulomatous suppurative lesions involving bone and soft tissue

Actinomyces bovis

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Group D, mostly alpha hemolytic, endocarditis and 10-15% of canine UTIs

Enterococcus spp.

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A zone of greening or partial hemolysis. Most are commensals.

Streptococcus Alpha Hemolysis

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Listeria distribution? Route of entry?

-Soil, plants, decaying vegetation, intestinal tract of over 50 spp. of animals…remarkable resistance to drying, survives months -Ingestion 1º route of entry, may enter through damaged mucosa in oral cavity

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Small Gram+ rods, anaerobic -cystitis and pyelonephritis of swine

Actinobaculum suis

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Large Gram+, spore-forming, aerobic rods -ubiquitous in soil, air, dust, water

Bacillus spp.

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-Broad spectrum bacteriostatic by inhibiting protein synthesis -most resistance is plasmid mediated chloramphenicol acetyltransferases

Chloramphenicol, Florfenicol

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Antibiotics SUPPRESS/ENHANCE gut flora?

Suppress, ex. salmonella infection in mice

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Pathogenesis of Listeria monocytogenes 1. Intestinal ____ (enteritis) 2. Intestinal ____ 3. Replication in the _____ and _____ 4. Resolution or spread 5. Clinical presentations _________, ________, ________

colonization 2. translocation 3. liver and spleen 5. Abortion, Meningoencephalitis (circling disease), visceral/septicemic disease

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Gram+ cocci, tend to be in clusters or bunches of grapes -commensals of upper respiratory tract and skin of all warm-blood animals -most infections endogenous -prolonged survival inanimate environments: resist high [salt], lipids, drying, etc. -spread of strains between different animal species is limited -pyogenic, associated with abscess formation and suppuration -Chronic pyoderma *does not cause food poisoning or enteritis in animals

Staphylococcus

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Widely but unevenly distributed in soils and aquatic environments -growth and toxin in anaerobic environments (contaminated meat, fish, carcasses, rotting vegetation) -suppresses release of ACh at myoneural junctions–flaccid paralysis -most common in water birds, ruminants, horses, mink and poultry *7 serotypes

Clostridium botulinum

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Genetic development of bacterial resistance (2)

Conjugation of a “common gene pool” -transfer of complete genes or sequence mediated by conjugative plasmid exchange 2. Transduction -phage mediated transfer of genes

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Neurotoxic clostridia?

C. tetani, C. botulinum -potent exotoxins, limited colonization or invasiveness

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Actinomyces spp. 1. viscosus 2. hordeovulnaris

cutaneous pyogranulomas, pyothorax, osteomyelitis 2. same, often associated w/ tissue migrating foxtail awns

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-rapidly bactericidal, targeting 2 types of topoisomerases (aid in DNA unwinding) -potent, broad spectrum…limited activity against anaerobes, streptococci -Resistance: stepwise mutations of DNA gyrase and topoisomerase IV genes w/ cross resistance, efflux pumps, conjugation -floxacin (enrofloxacin is Baytril)

Fluoroquinolones

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Erythromycin, tilmicosin, azithromycin, clarithromycin, tylosin, tulathromycin -bacteriostatic by inhibiting protein synthesis -active against G+ aerobes, mycoplasma and anaerobes

Macrolides

What is the name of the plasmid necessary to arrest phagosome maturation in R. equi?

Virulence Associated Plasmid A (vapA)

Small Gram+ rods, facultative anaerobe -MOST COMMON PYOGENIC AGENT OF CATTLE -commensal of mucous membrane and skin of cattle, goats, sheep and pigs -weak hemolysin toxic for epithelial cells and variety of phagocytic cells \*susceptible to penicillins, tetracyclines, sulfas

Trueperella pyogenes

Small, pleomorphic Gram+ rods, diptheroids -skin and mucous membranes and in lesions (i.e. shearing) -survives on exposed pen floor 10 days, in hay and bedding more than 1 year -facultative intracellular pathogen -sphingomyelinase-specific phospholipase D (exotoxin) causes hemolysis, increased vascular permeability and cytolysis \*\*major protective antigen

Corynebacterium pseudotuberculosis

Sporulation ideal environment

Calcium-rich, moist alkaline (pH 9) -resistant to extremes of heat, cold, pH, desiccation, chemicals etc. -UV inactivates spores in 4-6 hrs

Lancefield group A, ß-hemolytic, pharyngitis/tonsilitis of humans

Streptococcus pyogenes

-Most common pyogenic agent of dogs, pyoderma, infections of resp. tract, bones, joints, wounds, etc. -Rarely isolated from cats, humans, cattle, wild foxes, bears, horses, parrot

Staphylococcus pseudointermedius

Histotoxic -Causes malignant edema in ruminants, pigs, horses -1ºly enters and grows in wounds

Clostridium septicum

ß-Lactam drugs, inhibit cell wall synthesis, rapidly bactericidal -acquired resistance primarily by production of ß-lactamases -3rd generation active against gram negatives

Cephalosporins

Carbohydrates that nurture growth of specific fermentative probiotic organisms in colon -short or long chained oligosaccharides, not digestible by mammalian digestive enzymes but fermented in colon -beneficially affects host by selectively stimulating growth of limited # bacteria in colon, improving health

Prebiotics

-Bacteriostatic -Bactericidal combination w/ sulfa -broad spectrum of activity -cross resistance by plasmid mediated alternative enzyme or over production of targeted enzyme -competitive analogs of p-aminobenzoic acid in the synthesis of folic acid

Sulfonamide

The lowest concentration of drug that visibly inhibits growth of bacteria following 18-22 hours of incubation.

Minimum Inhibitory Concentration (MIC)

Small, motile Gram+ rods -Circling disease in ruminants, Rhombencephalitis -food borne infection (gastroenteritis is RARE)

Listeria

Metastatic abscessation at any site...sequelae of strangles

Bastard Strangles

Enterocolitis -Antibiotic associated diarrhea and pseudomembranous colitis 1ºly in humans -enterocolitis and diarrhea in horses, pigs, dogs -nosocomial problem, some strains=increased virulence -no vaccine

Clostridium difficile

Dermatophilus congolensis

-pleomorphic beaded chains, G+ -reside in foci of infection on carrier animals or w/in scabs in environment -superficial dermatitis w/ thick crusts, hair loss in scabs -affects cattle horses sheep goats etc. -lumpy wool, rain scald, strawberry footrot -Penicillins, tetracyclines

Presence of exotoxin, endotoxin, or other noxious substance in the circulating blood

Toxemia, toxic

Antimicrobial selections for Staphylococcus? Predictable susceptibility? Resistance issues?

Predictable susceptibility: penicillinase-resistant penicillins, cephalosporins, clavulanate/amoxicillin, macrolides, lincosamides, trimethoprim/suflas, chloramphenicol, aminoglycosides, quinolones, vancomycin Resistance issues: ß-lactams, tetracyclines

What do these have activity against? ß-Lactams Chloramphenicol Fluoroquinolones Macrolides Tetracyclines Sulfonamides

Gram Positive Aerobes

Groups D, R, S, Pneumonia, septicemia, arthritis, meningitis associated with pigs

Streptococcus suis

Live microorganisms, confer health benefit on host -bacteria or fungi

Probiotics

-Aerobic, saprophytic (dead or decaying organisms) soil organisms -partial acidfast staining differs from actinomyces -suppurative and pyogranulomatous rxns in immunosuppressed hosts or compromised tissues -rarely produce sulfur granules

Nocardia spp.

Pyogenic infection

Pus producing, bacteria enter tissues or attach and colonize, Adhesins include M protein, capsule, teichoic acids

Bacteroides Porphyromonas Prevotella Fusobacterium

Gram Negative Anaerobes

Necrotizing vasculitis associated with circulating immune complexes of IgA antibodies and M protein...sequelae of strangles

Purpura hemorrhagica

Antibiotic susceptibility of Erysipelothrix?

Penicillin, tetracyclines

Histotoxic clostridia?

C. chauvoei, septicum, novyi, soredellii, perfringens -Invasive and potent exotoxin producers resulting in acute necrosis of tissues (wounds, muscle, liver) includes gas gangrene

Staphylococcus virulence factors? (4)

1. Invasive (spreading) enzymes (hyaluronidase, proteases, lipases, fibrinolytic enzymes) 2. Cytolysins and leukotoxins, hemolysins 3. Capsules and Protein A 4. Superantigens

Broad, Gram+, rod, squared ends, chains common, capsule in vivo -more fragile than other Bacillus species -spontaneously die in water, milk, soil, putrefying carcass etc. -requires free O2 -most spores form from carcass w/in 48 hrs -transmission of spores while grazing, seasonal -\*\*lesion necessary for initiation of infection -spores phagocytosed by macs, migrate to LN -local edema, hemorrhage, necrosis

Bacillus anthracis

-Lancefield group G, ß-hemolytic, neonatal septicemia, genital, skin and wound infections -Canine streptococcal toxic shock syndrome and necrotizing fasciitis

Streptococcus canis

Produce exotoxins active within intestinal tract causing necrosis, food poisoning, diarrhea. i.e. C. perfringens, C. difficile

Enterocolitis

Short, pleomorphic Gram+ rods -lower genital tract of cattle and other ruminants -direct contact and indirectly by urine splashing -pili-mediated attachment to uroepithelium -metabolize large quantities of urea -chronic ascending pyonecrotic UTI -Ovine posthitis (PIZZLE ROT!!!), necrotizing inflammation of prepuce \*Penicillin AB of choice

Corynebacterium renale

What causes caseous lymphadenitis? What species?

Corynebacterium pseudotuberculosis Goats and sheep with multiple chronic abscesses resulting in debilitation, weight loss, poor production

Pleomorphic, small Gram+ rods -swine most frequently and severely affected -persistent and widespread, 5-42ºC, mammal and bird spp., slime layer of freshwater and saltwater fish and crustacea, carrier pigs considered 1º reservoir -survives drying for several months -spread by ingestion of contaminated materials (also wound contamination)

Erysipelothrix rhusiopathiae

What is the most important Listeria pathogen?

L. monocytogenes

Histotoxic -causes blackleg in ruminants, 1ºly cattle -spore ingested, carried to muscle, growth facilitated by anaerobic conditions -usually results in sudden death

Clostridium chauvoei

Lancefield group C, ß-hemolytic, common pyogenic agent in many species of animals -most common pyogenic agent of horses

Streptococcus equi ssp. zooepidemicus

Exudative epidermitis (greasy pig disease) of piglets -crowded, dirty muddy environment makes pigs mor susceptible

Staphylococcus hyicus

-from dolphins, horses, camels, mink, domestic pidgeons -Most common SIG from horses

Staphylococcus delphini

Staphylococcus Streptococcus Enterococcus Erysipelothrix Listeria Bacillus Corynebacterium

Gram Positive Aerobes

Actinomyces Clostridium Peptostreptococcus

Gram Positive Anaerobes

Are Staphylococcus strains typically host species-specific?

Yes, i.e. S. aureus (bumble foot, botryomycosis)

-Lancefield group B, chronic bovine mastitis -CAMP positive: Synergistic "arrow-head" hemolysis at intersection of Strep. and Staph. on blood agar

Streptococcus agalactiae

What does a Coagulase test indicate for Staphylococcus spp?

Positive- strains correlate well w/ pathogenicity (S. aureus, S. intermedius), double zone of hemolysis Negative- strains usually normal skin microbiota, limited virulence

What do these have activity against? Aminoglycosides ß-Lactams Chloramphenicol Fluoroquinolones Sulfonamides Tetracyclines

Gram Negative Aerobes

E. Coli Salmonella Klebsiella Pasteurella Pseudomonas Proteus

Gram Negative Aerobes

Where does R. equi normally occur? How is it acquired?

Occurs in soil and manure (2ºly intestine of mammals and birds). Optimal growth in presence of horse manure (10-41ºC). Acquired by inhalation of dust (seasonal appearance), ingestion, umbilicus.

Filamentous, branching, Gram+ rods -mucous membranes, oral cavity, nasopharynx -endogenous infections causing pyogenic or pyogranulomatous rxns -'sulfur granules' in tissues and exudate -obligate anaerobes or capnophilic (thrive in presence of high [CO2])

Actinomyces spp. (Actinomycosis)

-Lancefield Group C, ß-hemolytic -Strangles of Equidae -cause contagious disease, transmitted only by carriers

Streptococcus equi ssp. equi

When are foals most at risk for infection by R. equi? Why?

6-12 weeks of age, maternal AB declines

Gram+ cocci (single, pairs, chains) -Commensals-upper resp, genital, digestive -upper respiratory infection, lymphadenitis, neonatal septicemia, secondary pneumonia, pyogenic infections -may survive weeks in dried pus, soil, bedding -spread via aerosols, direct contact, or fomites \*infections primarily endogenous

Streptococcus

Broad-spectrum, bacteriostatic by inhibiting protein synthesis -against G+ and G- aerobes and anaerobes, mycoplasmas, rickettsiae, chlamydiae, spirochetes, and some protozoa -prevent elongation of polypeptide chain -most resistance is plasmid mediated efflux pumps \*cross resistance=broad spectrum, resistant regardless of which type

Tetracyclines

Nocardia asteroides

-cutaneous granulomas and pyothorax in dogs -mastitis in cattle -pneumonia in SCID foals -Trimethoprim/sulfas, tetracyclines

Antimicrobial resistance mechanisms (5)

1. Intrinsic resistance 2. Enzyme Production 3. Efflux Pumps 4. Altered drug receptor or binding site 5. Development of alternative pathways

What causes ulcerative lymphangitis? What species? What anatomical areas?

Corynebacterium pseudotuberculosis Horses Deep abscesses in inguinal and pectoral regions (pigeon breast, pigeon fever, dryland distemper)

ß-Lactam drugs, inhibit cell wall synthesis, rapidly bactericidal -effective against Gram+ aerobes and most anaerobes -acquired resistance primarily by production of ß-lactamases

Penicillin

Disease syndromes of Erysipelas in swine: (4)

Acute septicemia BIRDS MARINE MAMMALS (fatal) Urticarial form (Diamond skin disease) Vegetative endocarditis (chronic form) BIRDS DOGS Polyarthritis (chronic form) BIRDS SHEEP Bacteremia DOGS

Enterocolitis -Enterotoxemia: potent lethal toxins produced in intestine by overgrowth (over-eating disease) -absorbed, toxemia, septic shock, death -Enterotoxin ingested=food poisoning -Enterotoxin produced in lg intestine when bacteria convert to spores, causes diarrhea

Clostridium perfringens

Antibiotic susceptibility of Listeria?

penicillin/ampicillin, sulfonamides, tetracyclines, chloramphenicol, erythromycin, cephalosporins

Large Gram+ rods, obligate anaerobes, spore-forming -resistant to drying, heat, irradiation, disinfectants -soil, freshwater, marine sediments, intestinal tract of animals and humans -infection acquired by wound contamination, ingestion

Clostridium

Presence of viable bacteria in the circulating blood

Bacteremia

Exam 1 Flashcards

(85 cards)