Common Bacterial Pathogens Flashcards Preview

Disease & Defense - Unit 2 > Common Bacterial Pathogens > Flashcards

Flashcards in Common Bacterial Pathogens Deck (52)
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1
Q

Staphylococcus aureus bacteria type

A
  1. gram+ cocci in clusters 2. catalase positive
2
Q

Staphylococcus aureus primary sites

A

anterior nares and perineum

3
Q

Staphylococcus aureus types of infection

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

Staphylococcus aureus: cutaneous infection virulence factors

A

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

5
Q

Staphylococcus aureus: toxin-mediated disease virulence factor and example

A

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

6
Q

Staphylococcus epidermidis species group

A

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

7
Q

Staphylococcus epidermidis: most common infection

A

bacterial endocarditis

8
Q

Main species w/in genus Streptococcus

A
  1. Streptococcus pyogenes 2. Streptococcus pneumoniae 3. Enterococcus faecalis/Enterococcus faecium
9
Q

Main characteristics of genus Streptococcus

A
  1. gram+ cocci in chains/pairs 2. catalase negative
10
Q

Streptococcus pyogenes types of infection

A
  1. pharyngeal infection (strep throat) 2. skin and wound infection (cellulitis) 3. Post-streptococcal infections: a. glomerulonephritis b. rheumatic fever
11
Q

Streptococcus pneumoniae bacteria structure

A

gram+ cocci in pairs; “diplococci” or “pneumococcus”

12
Q

Streptococcus pneumoniae typical location

A

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

13
Q

Streptococcus pneumoniae: common infections

A
  1. frequent cause of pneumonia 2. sinusitis 3. otitis media 4. bronchitis 5. meningitis 6. bacteremia/septicemia
14
Q

Streptococcus pneumoniae pathogenesis

A

antiphagocytic polysaccaride capsule allows bacteria to evade host defenses

15
Q

Streptococcus pneumoniaevaccines

A
  1. adult=protect against invasive but not pneumonia 2. children=reduces disease in vaccinated
16
Q

Viridans streptococci typical location

A

abundant in mouth

17
Q

Viridans streptococci: common infections

A
  1. important cause of bacterial endocarditis 2. dental caries
18
Q

Viridans streptococci: pathogenesis

A

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

19
Q

Enterococcus faecalis & faecium typical location

A

normal flora of the intestines

20
Q

Enterococcus faecalis & faecium: common sites of infection

A
  1. urinary tract 2. surgical wounds 3. biliary tract 4. endocarditis
21
Q

Bacteria types w/in genus Clostridium

A

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

22
Q

Clostridium difficile: common infections

A
  1. hospital-aquired diarrhea 2. hospital-aquired pseudomembranous colitis
23
Q

Clostridium difficile: typical location

A

gut flora of ~10% of healthy people

24
Q

Clostridium difficile:pathogenesis

A
  1. depletion of gut flora by antibiotic treatment 2. overgrowth of C. difficile 3. enterotoxin 4. potent cytotoxin
25
Q

Clostridium tetani pathogenesis

A

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

26
Q

Clostridium botulinum pathogenesis

A

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

27
Q

Clostridium perfringens: common infections

A
  1. wound infection (gangrene, cellulitis, etc.) 2. food poisoning
28
Q

Clostridium perfringens wound infection pathogenesis

A

anaerobic; alpha toxin production

29
Q

Clostridium perfringens food poisoning pathogenesis

A

consumed with contaminated food; produce enterotoxin that disrupts tight jxns

30
Q

Typical Gram- rods

A
  1. E. Coli (Escherichia Coli) 2. Pseudomonas aeruginosa
31
Q

E. Coli: typical location

A

normal gut flora

32
Q

E. Coli: sensitivity to antibiotics

A

sensitive to most antibiotics, one of most common organisms to aquire resistance via drug-resistant plasmids

33
Q

E. Coli: common infections

A
  1. GI disease 2. UTI 3. Abdominal infection
34
Q

E. Coli: GI disease pathogenesis

A

consume contaminated food/water –> adherence to intestinal mucosa –> toxins disrupt gut electrolyte balane –> “traveler’s diarrhea”

35
Q

E. Coli: UTI pathogenesis

A

endogenous bacteria from gut –> adherence to bladder epithelium + B-hemolysis –> UTI

36
Q

E. Coli: Abdominal Infections pathogenesis

A

contents of colon escape into preitoneal cavity –> anaerobic abcess

37
Q

Pseudomonas aeruginosa: common infections

A
  1. infection of traumatic injuries, surgical wounds, and BURNS (opportunistic) 2. chronic lung infection (cystic fibrosis pts) 3. hospital-aquired infections
38
Q

Pseudomonas aeruginosa: antibiotic susceptibility

A

intrinsically resistant to many antimicrobials; must treat w/specialized regimen

39
Q

Neisseria gonorrhaeae: bacterial structure

A

gram - diplococcus

40
Q

Neisseria gonorrhaeae: common infections

A
  1. gonorrhea 2. conjuctivitis (–>blindness) in infants born to infected mothers
41
Q

Neisseria gonorrhaeae: pathogenesis

A

pilus=key to adherence and avoidance of neutrophils + antigenic variation avoids recognition; growth on mucosal surface –> inflammatory response –> purulent discharge

42
Q

Neisseria gonorrhaeae: antibiotic resistance

A
  1. penicillin 2. fluroquinolone 3. some cephalosporins
43
Q

Anaerobic bacteria: typical location

A

normal flora in various body nitches e.g. colon, mouth, female genital tract, skin

44
Q

Anaerobic bacteria: common disease properties

A
  1. endogenous origin 2. abscess formation 3. mixed infections (w/aerobic and anaerobic bacteria)
45
Q

Bacteriodes fragilis: common infections

A

responsible for >80% of intraabdominal infections

46
Q

Bacteriodes fragilis: bacteria type

A

anaerobic bacteria but relatively aerotolerant

47
Q

Bacteriodes fragilis: virulence factors

A
  1. tissue destructive enzymes 2. antiphagocytic capsule 3. superoxide dismutase
48
Q

Chlamydia trachomatis: bacteria type

A

obligate intracellular bacteria

49
Q

Chlamydia trachomatis: common infections

A
  1. trachoma (conjuctiva infection) 2. genital infections 3. neonatal infections
50
Q

Mycoplasma pneumoniae: bacteria type

A

bacterium w/out cell wall; contains sterols in plasma membrane

51
Q

Mycoplasma pneumoniae: common infections

A

one of most common causes of pneumonia; mild infection

52
Q

Mycoplasma pneumoniae: pathogenesis

A

adheres to respiratory cells –> extracellular growth –> hydrogen peroxide + superoxide radical production –> host tissue damage