N/V Flashcards
1
Q
Staphylococcus aureus
A
N/V
•Gr (+) cocci that form grapelike clusters
•Commonly found: skin, hair, noses, and throats of 25-30% of healthy people
•Commonly, a food handler contaminates food during preparation–>not properly refrigerated–>bacteria multiply quickly at room temperature and produce a *heat stable toxin
Disease
-vomiting
-Leading cause of HAI; most common cause of surgical infections
•May cause toxic shock syndrome (TSS), staphylococcal food poisoning or staphylococcal scalded-skin syndrome (SSSS
Virulence
-Enterotoxins A-E
2
Q
Bacillus cereus
A
N/V •Gr (+) rod, often in chains •Facultative anaerobic, •Beta hemolytic, •Catalase + •*Endospore-forming, •Large motile (flagella); swarming motility •Widespread in the environment & often is isolated from *soil and vegetation •at risk those who consume contaminated food, with penetrating injuries (e.g., to eye), who receive intravenous injections & immunocompromised patients exposed to B. cereus Disease -emetic or diarrheal food poisoning -vomiting Virulence emetic disease -*cereulide diarrheal disease -*hemolysin, non-hemolytic enterotoxin, and cytotoxin
3
Q
Clostridium perfringens
A
N/V •Gr (+) rod, •*Anaerobic •*endospore-forming •Boxcar or rectangular-shape; in pairs or short chains •Capsule •Non-motile •“Double-zone hemolysis -commonly found in *meat-containing food •Outbreaks associated with institutional settings •More severe in infants, young children and elderly Disease •*Watery diarrhea •*Gastroenteritis •Enteritis necroticans Virulence Toxins o*beta toxin (pathogenesis) o*Enterotoxin (CPE) oAlpha toxin α oTheta toxin θ oEpsilon toxin ε oIota toxin ι Spreading factors oDNase oHyaluronidase oCollagenase Labs •*Egg yolk agar is used to demonstrate the presence of the lecithinase (alpha toxin)
4
Q
Clostridium botulinum
A
N/V •Gr (+) rod •*Anaerobic, spore forming •Spores in *soil/ marine Disease -causes *flaccid paralysis Virulence •7 Botulinum Toxin (A-G, but A & B most common) -*Botulism toxin (super bad)
5
Q
Rotavirus
reoviridae
A
N/V oSegmented, ds RNA genome oIcosahedral with a *double capsid structure oNaked (non-enveloped) oReplicates in the cytoplasm •Look like *“wheels” under electron microscopy •Fecal-oral transmission •Severe disease in young children between 6 months and 2 years old, premature infants &elderly -vaccine available Disease -watery Diarrhea -vomiting
6
Q
Norovirus
Caliciviridae
A
N/V oSingle-stranded, positive-sense linear RNA genome oIcosahedral oNaked (non-enveloped) oSmall (27-40 nm) oReplicates in the cytoplasm -undergoes *antigenic drift over time •Fecal-oral mainly but also vomitus-oral •Commonly contaminated foods •More severe in children Disease -acute-onset vomiting (explosive) -may have HA, fever, chills, or myalgias Virulence -genetic resistance to infix -*histoblood group antigen expression
7
Q
Astrovirus
Astroviridae
A
N/V oSingle-stranded, positive-sense linear RNA genome oIcosahedral (like 5-6 sided star) oNaked (non-enveloped) oSmall (35 nm) oReplicates in the cytoplasm •Fecal-oral transmission Disease •Causes mild gastroenteritis in toddlers, school children, elderly in nursing homes & immunocompromised patients
8
Q
Adenoviruses
A
N/V •Double-stranded, linear *DNA genome •Icosahedral •Naked (non-enveloped) •Medium (90 nm) •*Replicates in the nucleus •Fecal-oral transmission -contaminated *fomite transmission -*respiratory droplets Disease -respiratory infx -pharyngoconjunctivits -acute respiratory disease Virulence •May establish “latency” in adenoids, tonsils, or intestines so it can shed without causing disease -*hemagglutinin (12 vertices)
