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Flashcards in Gram Negative Opportunistic Pathogens Deck (26):
1

what is an opportunistic infection

infections that only cause disease in compromised peope

-immunocompromised
-physical barrier breaches
-alterations in innate protective mechanisms

2

where are Gm-OP found?

numerous environements and survive in diverse conditions

3

LPS contributes symptoms of infections

ok

4

why are opportunistic infections increasing?

increased scope of surgical treatments, implants, and transplants

increased indwelling devices

increased capacity to sustain chronically ill

increased interventions that cause immunosuppression

immunosuppression from primary infection

5

OPs cause pneumonia. what factors contribute?

lung/heart/CNS/ or cancer diseases

surgery (in elderly and procedures that prevent coughing)

mechanical ventilation

lying flat

sedation

6

nosocomial infeciton

infection occurs in hospital

7

biofilms

dense microbial communities surrounded by ECMs

associated w/ implants and catheter infections

8

what is the most common OP and what does it cause?

E coli

1 GI
2 UTI
3 bacteremia
4 meningitis

9

uropathogenic E coli symptoms

UPEC

cause 95% of hospital acquired UTIs. women more suceptible

cystitis (bladder)- dysuria (burning), frequency, urgency, suprapubic tenderness

pylenophritis- UTI in the kidney- flank pain, tenderness/fever, dysuria, frequency, urgency

10

UPEC adhesins/disease

pilli or fimbrae

pili/fimbriae
-P pili (MR) Pyelonephritis/cystitis

-Prs pili (MR) Cystitis
-Type 1 pili (MS) Cystitis
-S pili (MR) Cystitis

nonfimbrial adhesin
-F adhesin (MR) Pyelonephritis

-Dr adhesin (MR) Cystitis

MR = mannose resistant
MS = mannose sensitivity

11

what is a common cause of UTI?

catheter use

12

not all humans are equivalent in terms of disease susceptibility

characteristics of your blood group (ex. globoseries Gal-Gal constituent) affect which cells bacteria can adhere to

13

e coli bacteremia

leading cause of nosocomial bacteremia is e coli

common routes are UTIs or indwelling medical devices (unknown how)

has resistance related to k1 capsule

causes systemic rxn to LPS/endotoxin

14

neonatal meningitis

caused by e coli K1

unknown how it gets to CNS, but capsule is important

proliferation in CSF is important, siderophores in particular cause damage

15

pseudomonas aeruginosa infections

burns, catheters, implanted devices, ventilator pneumonia, eyes, bacteremia

chronic indections- occur in lung w/ diseases like COPD or CF

16

P. aeruginosa toxins

endotoxin

exotoxins- proteases, elastases, phospholipases

some secreted by T3SS

17

pyocyanin

P aeruginosa produces blue/green pigment- toxic ROS

18

P. aeruginosa cannot ferment sugars. considered obligate aerobe

ok

19

clinical syndromes of klebsiella pneumoniae

pneumonia w/ underlying medical problems (alcoholism)
- causes red jelly sputum

UTI

wounds

bactermia/meningitis

diarrhea

20

most important klebsiella pneumoniae virulence factor

main virulence factor is capsule

21

enterobacter cloacae

associated w/ burn, wound, UTI, repiratory

infection occurs secondary to antibiotic therapy

lactose fermenter

22

serratia marcesens

prodigiosins produce red color

infections secondary to antibiotic therpy

forms biofilms

infections are respiratory and UTI, GI in neonates

associated w/ heroin addicts or septic arthritis outside hospital

23

serratia marcesens virulence factors

fimbrae, proteases, siderophores, swarming motility

24

proteus vulgaris, proteus mirabilis

UTIs

flagella (swarming motility) and urease synthesis (break down ura to increase pH and causing stone formation) are two pathogenic mechanisms

25

acinetobacter

oxidase nonfermenter, short rod

associated w/ indwelling medical devices

most intrinically antibiotic resistant bug

26

diagnosis of OP

colony morphology- shape, color, smell

selective medium

biochemical tests (fermenter, gas production, urease, oxidase)