Bugs

Question 1

Staph aureus/epidermidis

characteristics

Answer 1

gram+
cocci
clustered
catalase +

Question 2

S. aureus

diseases

Answer 2

Cutaneous infection (foreign body associated)
Toxin mediated diseases -> superantigens
- scalded skin syndrome
- TSS (TSST)
- food poisoning, ingestion of SA toxin
pneumonia (esp. in-patient)
foreign body assoc. infection
bacteremia/endocarditis

Question 3

causative agents of bacterial endocarditis

Answer 3

S. aureus
Streptococci ‘viridans’
coagulase neg. Staphylococci

Question 4

Steptococcus characteristics

Answer 4

Gram+
cocci
chains
catalase -

Question 5

Pertinent Strep family members + diseases

Answer 5

S. pyogenes “Group A Strep”
- pharyngeal infection (M-protein, recovery requires M-protein antibody)
- skin and wound infections (spreading infections)
S. pneumoniae (diplococci)
- non-invasive pneumonia, sinusitis, otitis media, bronchitis
- invasive meningitis, bacteremia/septicemia, pneumonia + septicemia
- grow and evade -> CAPSULE
“Viridans streptococci”
- bacterial endocarditis
- alpha or non-hemolytic
- abundant in mouth (dental carries)
Enterococci

Question 6

M-protein function

Answer 6

surface exposed protein

• inhibits phagocytosis and killing by PMNs
• enhances adherence to epithelial cells

Question 7

Post-streptococcoal diseases

Answer 7

Glomerulonephritis (Type III immunopathology)
Rheumatic Fever (Type II)

Question 8

Discuss child pneumococcal vaccine

Answer 8

7- or newer 13-valent

conjugate

Question 9

Adult pneumococcal vaccine

Answer 9

23 valent
‘pneumonia vaccine’ -> no resistance to pneumonia
protection against invasive disease

Question 10

Enterococci diseases

Answer 10

E. faecalis and E. faecium

• normal flora
• emerging antibiotic resistance (VRE)
• urinary tract, surgical wounds, biliary tract, endocarditis
• nosocomial infections

Question 11

Gram+ cocci

Answer 11

Staphylococci
- aureus
- epidermidis
Streptococci
- pyogenes (GAS)
- pneumoniae
- "viridans"
Enterococci
- faecalis
- faecium

Question 12

Clostridium characteristics

Answer 12

G+
rod
strict anaerobes
endospore formers

Question 13

Clostridium family + diseases

Answer 13

C. difficile
- HAcq. diarrhea and colitis
- relatively antibiotic resistant
C. tetani
- tetanus
- blocks inhibitory neurons (spastic paralysis)
C. botulinum
- botulism
- ingestion of preformed toxin
- blocks neuromuscular jcts (flaccid paralysis)
C. perfringens and others
- gangrene/tissue infections (alpha toxin)
- food poisoning (enterotoxin, ingestion of bacteria)

Question 14

Gram+ rods

Answer 14

Clostridium

• difficile
• botulinum
• tetani
• perfringens

Question 15

E. coli characteristics

Answer 15

G-
rod
many different strains

Question 16

E. coli diseases

Answer 16

GI
- contaminated food/water
- ETEC (enterotoxigenic, traveler's diarrhea)
> adherence to intestinal mucosa
> toxin disrupting electrolyte balance
UTI
- endogenous from GI tract
- adherence to and interaction with bladder epithelium
- beta-hemolytic
Abd. infections
- escape of colon contents into peritoneal cavity
- often assoc. with anaerobic bacteria

Question 17

Pseudomonas characteristics

Answer 17

G-

rod

Question 18

Pseudomonas aeruginosa disease

Answer 18

Most of the population is highly resistant
Infections of traumatic injuries, esp BURNS
Chronic lung infections in pts w/CF
HAcq. infections
Intrinsic resistance to many antimicrobials

Question 19

G- rods

Answer 19

E. coli
Pseudomonas aeruginosa
Klebsiella

Question 20

Neisseria gonorrhoeae characteristics

Answer 20

G-

(diplo)cocci

Question 21

Neisseria diseases

Answer 21

gonorrhea
conjunctivities -> blindness
antigenically distinct pili
Scarring and fibrosis from long infection
- possible uterine fibrosis and infertility in females

Question 22

Neisseria antibiotic resistance

Answer 22

almost always penicillin
reduced sensitivity to cephalosporins
Fluroquinolone resistance highly prevalent

Question 23

G- cocci

Answer 23

Neisseria gonorrhoeae

Question 24

Bacteroides characteristics/disease

Answer 24

B. fragilis
anaerobic, but relatively aerotolerant
Small component of normal flora, but frequently found in abd. infections
tissue destructive enzymes, anti-phagocytic capsule, SOD

Question 25

Obligate intracellular bacteria

Answer 25

Rickettsia (rocky mtn spotted fever)

Chylamydia

Question 26

Chylamydia disease

Answer 26

C. trachomatis
Trachoma -> scarring/blindness
Genital infection
Neonatal infection
- conjunctivitis and pneumonia

Question 27

Wall-less bacteria

Answer 27

Mycoplasma

Ueraplasma

Question 28

Mycoplasma disease

Answer 28

common cause of pneumonia in younger people (5-20)
“walking pneumonia”
intrinsic penicillin resistance
Adherence to respiratory epithelial cells
Grows extracellular
H2O2 and superoxide radicals -> host tissue damage

Question 29

SSNA/CNS (coagulase neg staph) diseases

Answer 29

S. epidermidis
glycocalyx -> biofilm
adheres to foreign bodies or artificial/damaged heart valves
resistant, difficult to get drug to target (biofilm)

Question 30

Staph infection strategy

Answer 30

local infection, “wall it off”

Question 31

Strep infection strategy

Answer 31

spreading infection/invasion