Exam 1 Flashcards
(85 cards)
1
Q
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
A
Streptococcus
2
Q
- Lancefield Group C, ß-hemolytic
- Strangles of Equidae
- cause contagious disease, transmitted only by carriers
A
Streptococcus equi ssp. equi
3
Q
Pyogenic infection
A
Pus producing, bacteria enter tissues or attach and colonize, Adhesins include M protein, capsule, teichoic acids
4
Q
A clear zone around a colony on a blood agar plate. Most are pathogenic strains.
A
Streptococcus Beta Hemolysis
5
Q
A zone of greening or partial hemolysis. Most are commensals.
A
Streptococcus Alpha Hemolysis
6
Q
Lancefield group A, ß-hemolytic, pharyngitis/tonsilitis of humans
A
Streptococcus pyogenes
7
Q
Metastatic abscessation at any site…sequelae of strangles
A
Bastard Strangles
8
Q
Necrotizing vasculitis associated with circulating immune complexes of IgA antibodies and M protein…sequelae of strangles
A
Purpura hemorrhagica
9
Q
Lancefield group C, ß-hemolytic, common pyogenic agent in many species of animals
-most common pyogenic agent of horses
A
Streptococcus equi ssp. zooepidemicus
10
Q
- Lancefield group G, ß-hemolytic, neonatal septicemia, genital, skin and wound infections
- Canine streptococcal toxic shock syndrome and necrotizing fasciitis
A
Streptococcus canis
11
Q
- Lancefield group B, chronic bovine mastitis
- CAMP positive: Synergistic “arrow-head” hemolysis at intersection of Strep. and Staph. on blood agar
A
Streptococcus agalactiae
12
Q
Groups D, R, S, Pneumonia, septicemia, arthritis, meningitis
associated with pigs
A
Streptococcus suis
13
Q
Group D, mostly alpha hemolytic, endocarditis and 10-15% of canine UTIs
A
Enterococcus spp.
14
Q
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
A
Staphylococcus
15
Q
Staphylococcus virulence factors? (4)
A
- Invasive (spreading) enzymes (hyaluronidase, proteases, lipases, fibrinolytic enzymes)
- Cytolysins and leukotoxins, hemolysins
- Capsules and Protein A
- Superantigens
16
Q
What does a Coagulase test indicate for Staphylococcus spp?
A
Positive- strains correlate well w/ pathogenicity (S. aureus, S. intermedius), double zone of hemolysis
Negative- strains usually normal skin microbiota, limited virulence
17
Q
- 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
A
Staphylococcus pseudointermedius
18
Q
- from dolphins, horses, camels, mink, domestic pidgeons
- Most common SIG from horses
A
Staphylococcus delphini
19
Q
Are Staphylococcus strains typically host species-specific?
A
Yes, i.e. S. aureus (bumble foot, botryomycosis)
20
Q
Exudative epidermitis (greasy pig disease) of piglets -crowded, dirty muddy environment makes pigs mor susceptible
A
Staphylococcus hyicus
21
Q
Antimicrobial selections for Staphylococcus?
Predictable susceptibility?
Resistance issues?
A
Predictable susceptibility: penicillinase-resistant penicillins, cephalosporins, clavulanate/amoxicillin, macrolides, lincosamides, trimethoprim/suflas, chloramphenicol, aminoglycosides, quinolones, vancomycin
Resistance issues: ß-lactams, tetracyclines
22
Q
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
A
Rhodococcus equi
23
Q
Where does R. equi normally occur? How is it acquired?
A
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.
24
Q
When are foals most at risk for infection by R. equi? Why?
A
6-12 weeks of age, maternal AB declines
25
What is the name of the plasmid necessary to arrest phagosome maturation in R. equi?
Virulence Associated Plasmid A (vapA)
26
What kind of organisms are the majority of microbiota?
Obligate anaerobes (40-80% Gram+, 40-60% Gram-)
27
Antibiotics SUPPRESS/ENHANCE gut flora?
Suppress, ex. salmonella infection in mice
28
Live microorganisms, confer health benefit on host
| -bacteria or fungi
Probiotics
29
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
30
Small, motile Gram+ rods
- Circling disease in ruminants, Rhombencephalitis
- food borne infection (gastroenteritis is RARE)
Listeria
31
What is the most important Listeria pathogen?
L. monocytogenes
32
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
33
Pathogenesis of Listeria monocytogenes
1. Intestinal ____ (enteritis)
2. Intestinal ____
3. Replication in the _____ and _____
4. Resolution or spread
5. Clinical presentations _________, ________, ________
1. colonization
2. translocation
3. liver and spleen
5. Abortion, Meningoencephalitis (circling disease), visceral/septicemic disease
34
Antibiotic susceptibility of Listeria?
penicillin/ampicillin, sulfonamides, tetracyclines, chloramphenicol, erythromycin, cephalosporins
35
Presence of viable bacteria in the circulating blood
Bacteremia
36
Presence of microorganisms and/or their products (toxins) in the circulating blood
Septicemia, septic, sepsis
37
Presence of exotoxin, endotoxin, or other noxious substance in the circulating blood
Toxemia, toxic
38
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
39
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
40
Antibiotic susceptibility of Erysipelothrix?
Penicillin, tetracyclines
41
What causes caseous lymphadenitis? What species?
Corynebacterium pseudotuberculosis
| Goats and sheep with multiple chronic abscesses resulting in debilitation, weight loss, poor production
42
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)
43
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
44
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
45
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
46
Small Gram+ rods, anaerobic
| -cystitis and pyelonephritis of swine
Actinobaculum suis
47
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
48
Neurotoxic clostridia?
C. tetani, C. botulinum
| -potent exotoxins, limited colonization or invasiveness
49
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
50
Produce exotoxins active within intestinal tract causing necrosis, food poisoning, diarrhea. i.e. C. perfringens, C. difficile
Enterocolitis
51
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
52
- 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
53
Histotoxic
- causes blackleg in ruminants, 1ºly cattle
- spore ingested, carried to muscle, growth facilitated by anaerobic conditions
- usually results in sudden death
Clostridium chauvoei
54
Histotoxic
- Causes malignant edema in ruminants, pigs, horses
- 1ºly enters and grows in wounds
Clostridium septicum
55
Histotoxic clostridia
1. Big head in rams?
2. Black disease (infectious necrotic hepatitis)?
3. Bacillary hemoglobinuria (redwater)?
1. C. novyi Type A
2. C. novyi Type B
3. C. haemolyticum (C. novyi Type D)
56
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
57
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
58
Large Gram+, spore-forming, aerobic rods
| -ubiquitous in soil, air, dust, water
Bacillus spp.
59
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
60
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
61
The lowest concentration of drug that visibly inhibits growth of bacteria following 18-22 hours of incubation.
Minimum Inhibitory Concentration (MIC)
62
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
63
Genetic development of bacterial resistance (2)
1. Conjugation of a "common gene pool"
- transfer of complete genes or sequence mediated by conjugative plasmid exchange
2. Transduction
- phage mediated transfer of genes
64
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
65
ß-Lactam drugs, inhibit cell wall synthesis, rapidly bactericidal
- acquired resistance primarily by production of ß-lactamases
- 3rd generation active against gram negatives
Cephalosporins
66
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
67
- Broad spectrum bacteriostatic by inhibiting protein synthesis
- most resistance is plasmid mediated chloramphenicol acetyltransferases
Chloramphenicol, Florfenicol
68
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
69
Erythromycin, tilmicosin, azithromycin, clarithromycin, tylosin, tulathromycin
- bacteriostatic by inhibiting protein synthesis
- active against G+ aerobes, mycoplasma and anaerobes
Macrolides
70
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
71
- 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
72
- 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
73
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What do these have activity against?
ß-Lactams
Chloramphenicol
Fluoroquinolones
Macrolides
Tetracyclines
Sulfonamides
```
Gram Positive Aerobes
74
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What do these have activity against?
Aminoglycosides
ß-Lactams
Chloramphenicol
Fluoroquinolones
Sulfonamides
Tetracyclines
```
Gram Negative Aerobes
75
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What do these have activity against?
ß-Lactams
Chloramphenicol
Macrolides
Metronidazole
Tetracyclines
Sulfonamides
```
Gram Positive Anaerobes and Gram Negative Anaerobes
76
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Staphylococcus
Streptococcus
Enterococcus
Erysipelothrix
Listeria
Bacillus
Corynebacterium
```
Gram Positive Aerobes
77
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E. Coli
Salmonella
Klebsiella
Pasteurella
Pseudomonas
Proteus
```
Gram Negative Aerobes
78
Actinomyces
Clostridium
Peptostreptococcus
Gram Positive Anaerobes
79
Bacteroides
Porphyromonas
Prevotella
Fusobacterium
Gram Negative Anaerobes
80
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)
81
"Lumpy Jaw"
| -chronic progressive, cattle, granulomatous suppurative lesions involving bone and soft tissue
Actinomyces bovis
82
Actinomyces spp.
1. viscosus
2. hordeovulnaris
1. cutaneous pyogranulomas, pyothorax, osteomyelitis
| 2. same, often associated w/ tissue migrating foxtail awns
83
- 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.
84
Nocardia asteroides
- cutaneous granulomas and pyothorax in dogs
- mastitis in cattle
- pneumonia in SCID foals
- Trimethoprim/sulfas, tetracyclines
85
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
