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144 Cards in this Set
- Front
- Back
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What are the main functions of bacterial capsules? |
protection from adverse environmental conditions (dessication)
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How does bacterial capusles contribute to virulence? |
inhibit phagocytosis, facilitate adherence to surfaces |
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What are capules primarily composed of? |
polyscahharides |
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Describe the cell wall of Gram positive bacteria |
thick uniform single layer composed of peptidoglycan |
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Describe the cell wall of Gram Negative bacteria |
inner and outer membranes
outer membrane is assymetrical and contains LPS |
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Describe the cell wall of Acid Fast bacteria |
like gram positive bacteria but with an extra "waxy" layer that does not stain well |
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What are the components of LPS? |
core pollysaccharide
Lipid A (PAMP)
Long external polysaccharide side chain (O Polysaccharide) |
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The cell wall of what type of bacteria contains LPS and what is its importance? |
Gram Negative LPS is the endotoxin of gram negative bacteria |
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What part of LPS is antigenic? |
O polysaccharide side chain |
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What bacteria are acid fast? |
Mycobacterium
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What is unique about the cell wall of mollicutes such as Mycolplasma? |
no cell wall, only cytoplasmic membrane |
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What color do Gram Negative bacteria stain with a gram stain? |
red |
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What color do Gram Positive bacteria stain with a gram stain? |
blue |
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Describe the cell wall of Mycobacterium |
like most bacteria: cell wall plus an extra waxy layer |
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Describe the cell wall of mycoplasma |
only a plasma membrane |
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Do gram positive or gram negative bacteria usually have flagella? |
Gram Negative |
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What are attachment pili also called? |
Fimbriae |
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Do mostly gram postive or negative have fimbriae? |
Gram negative |
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What is the function of fimbriae? |
attachment to host cells |
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What is the function of conjugation pili? |
dna transfer
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What are conjugation pili also called? |
F pilus, sex pilus |
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Describe the genetic material of bacteria. |
Haploid circular chromosome containing double stranded DNA. |
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What is a pathogenicity island? |
Genetic material that encodes clusters of virulence genes which have been acquired during evolution. May be incorporated into the genome or part of a plasmid or bacteriophage.
NOT present in avirulent strains |
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Why do some antibiotics target bacterial ribosomes? |
They differ from eukaryotic ribosomes |
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What genera of bacteria have endospores and what gram stain are they? |
Bacillus (Gram Positive) Clostridium (Gram Positive)
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What are endospores resistant to and why? |
Resistant to: environmental factors, disinfectants, antimicrobials.
Resistance attributed to layered structure, dehydrated state, negligible metabolic activity |
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What are the three types of genetic information bacteria can carry? |
chromosomes plasmids bacteriophages |
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What is recombination? |
combination of DNA when sequences from two separate sources are integrated
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How is genetic material transferred from one bacteria to another during recombination? |
Bacteriophage (virus) |
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What are the two types of bacteriophages and how are they different? |
Virulent/Lytic Bacteriophage undergo lytic cycle in bacteria and produce phage progeny with lysis of the host
Temperate/avirulent Bacteriophage dormant and integrated into bacterial genome can undergo lytic cycle if triggered |
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How does conjugation occur? |
Usually plasmid DNA is transfered via a conjugation pilus. |
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How does transformation occur? |
Direct uptake of "free" DNA without the use of a pilus. |
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What is a transposon? |
genetic element that can move as a single unit from one chromosome, plasmid, or bacteriophage to another, leaving a copy of itself behind. |
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Define pathogenicity. |
Ability to cause damage to a host |
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Define virulence. |
Severity of the damage to a host |
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Define virulence factor. |
bacterial traits that confer pathogenicity |
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What is horizontal transmission? |
Transmission of a bacteria from animal to animal |
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What is vertical transmission? |
Transmission of a pathogen from mother to offspring either transplacentally or via ingestion of colostrum. |
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What are the most common routes of entry of pathogens? |
inhalation, ingestions, urogenital |
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What are the characteristics of exotoxins? |
proteins secreted high potency non pyrogenic highly antigenic |
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What are the characteristics of endotoxins? |
cell wall, Lipid A released upon cell death low potency pyrogenic poorly antigenic |
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What are the 4 ways in which exotoxins work? |
1) disrupt extracellular matrix 2)disrupt plasma membrane 3) intracellular toxins that alter signaling or cytoskeleton 4) activate CD4 T cells |
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How do superantigens work? |
bind to MHC Class II molecules and T Cell Receptors crosslinking them which activates many Tcells causing cytokine release and inflammation |
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What type of cell predominates in a pyogenic suppurative infection? |
neutrophils |
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What type of cell predominates in a pyogranulomatous infection? |
neutrophils and macrophages |
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What type of cells predominate in a granulomatous infection? |
machrophages |
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In what type of environment does Staphylococcus live? |
skin (moist areas), mucous membranes of the upper respiratory tract and lower urogenital tract |
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True or false: Staphylococcus is stable in the environment |
True |
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How is Staphylococcus transmitted? |
endogenous direct contact fomites |
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What virulence factor is highly associated with pathogenicity of Staphylococcus bacteria? |
Coagulase |
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What type of infections does Staphyloccocus cause: pyogenic granulomatous pyogranulomatous |
pyogenic |
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What species of Staphylococcus is associated with mastitis in cattle? |
S. aureus |
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What species of Staphylococcus is associated with canine pyoderma and otitis externa? |
S. pseudintermedius |
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Exudative Epidermitis is a disease of what species of animal and what causes it? |
pigs, Staphylococcus hyicus |
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Which type of mastitis does staphylococcus aureus cause in cattle, contagious or environmental? |
contagious |
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What causes gangrenous mastitis in cattle? |
alpha toxin of Staphylococcus aureus |
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What bacteria causes broiler infections and what are the infections? |
Staphylococcus aureus Arthritis septicemia bumblefoot omphalitis |
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What are the common sources of Staphylococcus pseudintermedius in canines? |
nares, perineal region |
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What is the source of infection in piglets with Staphylococcus hyicus? |
vaginal mucosa and skin of healthy sows |
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What predisposing conditions result in infection with Staphylococcus hyicus? |
Agalactia weaning |
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What is the major virulence factor involved with Staphylococcus hyicus? |
Exfoliative toxin |
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What Staphylococcus species of veterinary importance in coagulase negative? |
Staphylococcus epidermidis |
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What are the most common virulence factors of Staphylococcus species and what is their importance? |
Capsule- inhibits phagocytosis Protein A- inhibits phagocytosis and inhibits opsoniztion Coagulase- indicator of virulence Toxins |
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What are the primary toxins of Staphylococcus species and what is their significance? |
Leukocidin- kills phagocytes Alpha toxin- necrotizing (gangrenous mastitis), smooth muscle spasms Exfoliative toxins- skin lesions Toxic Shock Syndrome Toxin- superantigen found in some bovine strains |
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What gene codes for Methicillin resistance in Staphylococcus species? |
MecA gene |
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How does the MecA gene cause methicillin resistance? |
alters penicillin binding protein inhibiting the binding of beta lactam antibiotics |
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What is the significance of Penicillin Binding Protein? |
catalyzes the crosslinking of petidoglycan in staphylococcus species stabilizing the peptidoglycan and the cell wall. It is what beta lactam antibiotics bind to to kill bacteria |
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True of False: Staphylococcus species are host specific? |
True |
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What is the morphology of Staphylococcus species? |
cocci in clusters |
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What is the morphology of Streptococcus species? |
cocci in chains |
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In what environments does Streptococcus live? |
mucous membranes moist environments |
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How is Streptococcus transmitted? |
endogenous direct contact |
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What type of infections do Streptococcus species cause? |
pyogenic |
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What is the Lancefield Grouping? |
A serologic classification scheme of streptococcus species based upon cell wall poysaccharides
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List the corresponding lancefield grouping for the following: Human Bovine Equine Canine Porcine |
Human-A Bovine-B (some C) Equine-C Canine- G Porcine- D
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What species of Streptococcus causes contagious bovine mastitis and what is its Lancefield Group? |
Streptococcus agalactiae Lancefield Group B |
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What Streptococcus species causes environmental mastitis in bovines and what is its Lancefield Group? |
Streptococcus uberis Lancefield Group B |
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What species of Streptococcus in Lancefield Group C causes bovine mastitis? |
Streptococcus dysglactiae |
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What is often the source of Streptococcus agalactiae caused mastitis? |
milk duct (obligate pathogen of the the teat canal) |
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What indicates a positive CAMP test and what is it used to test for? |
Arrow head pattern of haemolysis indicates the presence of Streptococcus agalactiae |
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Strangles is caused by what microorganism? |
Steptococcus equi ssp. equi |
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True or false: Strangles is caused by a commensal microorganism |
False: Streptococcus equi ssp equi is an obligate pathogen |
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Necrotizing fasciitis in canines is caused by what microorganism? |
Streptococcus canis |
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What microorganism in Lancefield Group D causes a variety of infections in swine? |
Streptococcus suis |
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What bacteria has vancomycin resistant strains? |
Enterococcus spp |
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What is the mode of action of Beta Lactam antibiotics? |
inhibits cell wall synthesis. |
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What is the mode of action of fluoroquinolones? |
inhibition of nucleic acid synthesis |
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What is the mode of action of tetracyclines? |
inhibition of protein synthesis |
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What is the mode of action of sulfonamides? |
inhibition of nucleic acid synthesis by blocking folic acid synthesis |
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What are the common mechanisms for antibiotic resistance? |
restriction of entry by cell wall enzymatic degradation of antibiotic alteration of the antibiotic target site elimination from cytoplasm alternative metabolic pathways |
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What in vivo factors influence antibiotic activity? |
site of administration rate of absorption site of excretions tissue distribution metabolism of drug site of the infection |
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In what environment does Actinomyces live? |
oral mucosa nasopharyngeal mucosa |
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How is Actinomyces transmitted? |
fomites direct contact endogenous |
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Sulfur granules are characteristic of what bacteria? |
Actinomyces
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Describe the morphology of Actinomyces |
rods with branching filaents resembling fungi |
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What causes "lumpy jaw" in cattle? |
Actinomyces bovis |
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Is Actinomyces bovis an aerobe or anaerobe? |
obligate anaerobe |
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What type of infections do Actinomyces bovis cause? |
endogenous granulomatous infection |
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What species of Actinomyces is not a commensal organism? |
Actinomyces hordeovulneris |
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What is the habitat of Actinomyces hordeovulneris? |
grass awns |
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What species of Actinomyces affects canines and what does it cause? |
Actinomyces viscosus cutaneous pyogranulomas pyothorax/pyogranulomatous pleuritis |
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What was Trueperella pyogenes former name? |
Arcanobacterium pyogenes |
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What type of infections does Trueperella pyogenes cause? |
suppurative or pyogranulomatous infections |
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How is Trueperella pyogenes transmitted? |
endogenous |
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What is the environment of Trueperella pyogenes? |
commensal to the mucous membranes of cattle and pigs |
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What diseases does Trueperella pyogenes cause in cattle? |
liver abscesses "foot rot" "summer" Mastitis |
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Infection caused by what bacteria is often associated with co-infection with another anaerobic microorganism? |
Trueperella pyogenes |
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What is the virulence factor of Trueperella pyogenes and what is its function? |
Pyolysin O- cytotoxic to neutrophis and epithelial cells |
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In what environment does Actinobaculum suis live? |
prepuce of healthy boars |
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How is Actinobaculum suis transmitted? |
coitus |
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What animals are affected by Actinobaculum suis and how? |
pregnant sows porcine cystitis and pyelonephritis |
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What are the staining characteristics of Nocardia? |
gram positive partially acid fast |
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In what environment does Nocardia reside? |
soil (saprophyte) |
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What type of infections are caused by Nocardia? |
granulomatous infections of immunosuppressed animals |
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Describe the morphology of Dermatophilus congolensis |
rods with branching filaments and motile zoospores |
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What is the environment in which Dermatophilus congolensis lives? |
skin, scabs |
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What microorganism causes Rain Rot andLumpy Wool |
Dermatophilus congolensis |
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What microorganism when looked at microscopically has a "railroad track" appearance? |
Dermatophilus congolensis |
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What is the morphology of Corynebacterium? |
pleomorphic (cocoid, rods, club) |
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How is Corynebacterium transmitted? |
direct indirect fomites |
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What is the typical environment in which Corynebacterium is found? |
mucous membranes environment |
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Of the bacteria that we have studied which consists of two biotypes and what distinguishes them? |
Corynebacterium ability to reduce nitrates |
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What microorganism causes Caseous Lymphadenitis? |
Corynebacterium pseudotuberculosis |
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What are the virulence factors of Corynebacterium pseudotuberculosis? |
phopholipase D- pore forming toxin Mycolic acid- resists killin |
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Corynebacterium renale causes what disease in cattle? |
Bovine Pyelonephritis and cystitis |
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What is a virulence factor of Corynebacterium renale? |
urease-- splits urea to ammonia and causes inflammation |
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Name a bacteria that is facultative intracellular |
Listeria monocytogenes |
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What is the habitat of Listeria monocytogenes? |
environment silage |
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What is the zoonotic importance of Listeria monocytogenes? |
causes foodborne disease |
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Infection with Listeria monocytogenes can result in what types of disease? |
encephalitis abortion septicemia |
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In animals, how does Listeria monocytogenes cause encephalitis? |
Ingeseted, penetrates oral mucosa and travels up cranial nerve to the brain |
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How does Listeria monocytogenes move within and between cells? |
polymerizes actin |
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What are some characteristic features of encephalitis caused by Listeria monocytogenes? |
unilateral involvement travels up cranial nerve unidirectional circling often seen |
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What is the environment in which Erysipelothrix rhusiopathiae lives? |
porcine tonsils |
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What faculative intracellular bacteria has a high zoonotic potential? |
Erysipelothrix rhusiopathiae |
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What doesErysipelothrix rhusiopathiae cause in swine? |
Septicemia Cutaneous "Diamond Skin Disease" Arthritis Endocarditis |
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Of the bacteria we have discussed, what bacteria forms spores? |
Bacillus anthracis |
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In what environment does Bacillus anthracis reside? |
the soil for up to 50 years |
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What are virulence factors of Bacillus anthracis? |
Capsule- resists phagocytosis Anthrax Toxins |
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Describe the anthrax toxins. |
3 toxins: Protective Antigen- binds to host cell and allows entry of active toxins Edema Factor- produces cAMP, alters water homeostasis and causes edema Lethal Factor- alters intracellular signaling and causes cell death |
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In what soil types does Bacillus anthracis thrive? |
alkaline calcium and nitrogen rich high moisture content |
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What are the most common signs of an anthrax infection? |
sudden death, incomplete rigor mortis, lack of coagulation of blood, bloating |
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What does Bacillus anthracis look like microscopically? |
large square ended rods |
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To whom do you report Bacillus anthracis infections to? |
Texas Animal and Health Commission |
