Common Bacterial Pathogens Flashcards Preview

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Flashcards in Common Bacterial Pathogens Deck (52)
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1

Staphylococcus aureus bacteria type

1. gram+ cocci in clusters 2. catalase positive

2

Staphylococcus aureus primary sites

anterior nares and perineum

3

Staphylococcus aureus types of infection

1. cutaneous infection 2. toxin-mediated disease 3. Pneumonia (hostpital-aquired) 4. foreign-body associated infections 5. bacteremia/endocarditis

4

Staphylococcus aureus: cutaneous infection virulence factors

coagulase=formation of fibrin capsule; alpha-toxin=cytotoxic agent

5

Staphylococcus aureus: toxin-mediated disease virulence factor and example

superantigen toxins=non-specific T cell activation (25% of body T cells: e.g. Staphylococcal Toxic Shock Syndrome

6

Staphylococcus epidermidis species group

SSNA=staph species, not aureus OR CNS=coagulase negative staphylococcus

7

Staphylococcus epidermidis: most common infection

bacterial endocarditis

8

Main species w/in genus Streptococcus

1. Streptococcus pyogenes 2. Streptococcus pneumoniae 3. Enterococcus faecalis/Enterococcus faecium

9

Main characteristics of genus Streptococcus

1. gram+ cocci in chains/pairs 2. catalase negative

10

Streptococcus pyogenes types of infection

1. pharyngeal infection (strep throat) 2. skin and wound infection (cellulitis) 3. Post-streptococcal infections: a. glomerulonephritis b. rheumatic fever

11

Streptococcus pneumoniae bacteria structure

gram+ cocci in pairs; "diplococci" or "pneumococcus"

12

Streptococcus pneumoniae typical location

normal flora in UR tract of up to 40% of healthy people

13

Streptococcus pneumoniae: common infections

1. frequent cause of pneumonia 2. sinusitis 3. otitis media 4. bronchitis 5. meningitis 6. bacteremia/septicemia

14

Streptococcus pneumoniae pathogenesis

antiphagocytic polysaccaride capsule allows bacteria to evade host defenses

15

Streptococcus pneumoniaevaccines

1. adult=protect against invasive but not pneumonia 2. children=reduces disease in vaccinated

16

Viridans streptococci typical location

abundant in mouth

17

Viridans streptococci: common infections

1. important cause of bacterial endocarditis 2. dental caries

18

Viridans streptococci: pathogenesis

gain access to bloodstream from mouth after dental manipulations and use dextrans to adhere to fibrin/platelet deposits on damaged heart valves

19

Enterococcus faecalis & faecium typical location

normal flora of the intestines

20

Enterococcus faecalis & faecium: common sites of infection

1. urinary tract 2. surgical wounds 3. biliary tract 4. endocarditis

21

Bacteria types w/in genus Clostridium

G+ rods: 1. strict anaerobes 2. endospore-formers

22

Clostridium difficile: common infections

1. hospital-aquired diarrhea 2. hospital-aquired pseudomembranous colitis

23

Clostridium difficile: typical location

gut flora of ~10% of healthy people

24

Clostridium difficile:pathogenesis

1. depletion of gut flora by antibiotic treatment 2. overgrowth of C. difficile 3. enterotoxin 4. potent cytotoxin

25

Clostridium tetani pathogenesis

"tetanus"=organism in soil/GI tract of animals-->infection (anaerobic + toxin production --> blocks interneurons in CNS

26

Clostridium botulinum pathogenesis

"botulism"=organism in soil/GI tract of animals--> contaminated food (anaerobic) + toxin production --> blocks Ach @ neuromuscular jxns

27

Clostridium perfringens: common infections

1. wound infection (gangrene, cellulitis, etc.) 2. food poisoning

28

Clostridium perfringens wound infection pathogenesis

anaerobic; alpha toxin production

29

Clostridium perfringens food poisoning pathogenesis

consumed with contaminated food; produce enterotoxin that disrupts tight jxns

30

Typical Gram- rods

1. E. Coli (Escherichia Coli) 2. Pseudomonas aeruginosa