Gram Negative Opportunistic Pathogens Flashcards
what is an opportunistic infection
infections that only cause disease in compromised peope
- immunocompromised
- physical barrier breaches
- alterations in innate protective mechanisms
where are Gm-OP found?
numerous environements and survive in diverse conditions
LPS contributes symptoms of infections
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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
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
nosocomial infeciton
infection occurs in hospital
biofilms
dense microbial communities surrounded by ECMs
associated w/ implants and catheter infections
what is the most common OP and what does it cause?
E coli
1 GI
2 UTI
3 bacteremia
4 meningitis
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
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
what is a common cause of UTI?
catheter use
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
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
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
pseudomonas aeruginosa infections
burns, catheters, implanted devices, ventilator pneumonia, eyes, bacteremia
chronic indections- occur in lung w/ diseases like COPD or CF
P. aeruginosa toxins
endotoxin
exotoxins- proteases, elastases, phospholipases
some secreted by T3SS
pyocyanin
P aeruginosa produces blue/green pigment- toxic ROS
P. aeruginosa cannot ferment sugars. considered obligate aerobe
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clinical syndromes of klebsiella pneumoniae
pneumonia w/ underlying medical problems (alcoholism)
- causes red jelly sputum
UTI
wounds
bactermia/meningitis
diarrhea
most important klebsiella pneumoniae virulence factor
main virulence factor is capsule
enterobacter cloacae
associated w/ burn, wound, UTI, repiratory
infection occurs secondary to antibiotic therapy
lactose fermenter
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
serratia marcesens virulence factors
fimbrae, proteases, siderophores, swarming motility
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
