Microbiology Flashcards
what is the lower end of the urethra colonised by?
coliforms
enterococci from large bowel
is the urinary tract sterile?
yes, except for lower end of urethra
risk factors for UTI
female
pregnancy
catheterised patients
abnormalities of urinary tract
what makes females more at risk of UTIs?
short, wide urethra
proximity of urethra to anus
sexual activity
gram negative causative organisms for UTI
coliforms (E. coli, klebsiella, enterobacter)
proteus
pseudomonas
presentation of proteus
foul smelling urine
renal calculi
associations with pseudomonas as causation of UTI
catheters
instrumentation
management of pseudomonas
ciprofloxacin
gram positive causative organisms for UTI
enterococcus (faecalis and faecium)
staph saphrophyticus
staph aureus
associations with enterococcus (faecalis and faecium) causing UTI
hospital acquired infections
who gets staph saphrophyticus?
coagulase negative staph affects women of child-bearing age
when does staph aureus cause a UTI?
usually only in bacteraemia
presentation of UTI
dysuria frequency nocturia haematuria if upper= fever, loin pain, rigors
diagnosis of UTI
- mid-stream sample (MSU)
- other urine samples e.g. clean catch urine, bag urine, catheter specimen (CSU) or suprapubic aspiration
- dipstick
- microscopy
how should a mid-stream sample MSU be transported to the lab?
boricon container
sterile universal container
when is dipstick not used in diagnosis of UTI?
elderly
catheter
what does a dipstick show?
leukocyte esterase (WBC)
nitrates (bacteria reduces nitrates)
protein
blood
when is microscopy used in UTI?
urgent cases to look for pus cells, bacteria +/- red cells
what criteria is used for culture of urine?
Kass’s criteria
Kass’s criteria
> 10^5 organisms/ml= probable UTI
10^4 organisms/ml = repeat specimen
<10^3 organisms/ml= not significant
mixed growth not significant
who does Kass’s criteria apply to?
women of childbearing age
antibiotic of choice for pseudomonas?
ciprofloxacin (c.diff)
antibiotic of choice for coliforms
gentamicin IV (hospital, narrow therapeutic range)
antibiotic of choice for enterococci faecalis
amoxicillin
if allergic then co-trimoxazole- SJS
what is ESBL resistant to?
cephalosporins
penicillin
antibiotic of choice for ESBL
nitrofurantoin
what is CPE resistant to?
all
associations with CPE
UTI and travel to india
what kind of organism is CPE
klebsiella
antibiotics safe to use in pregnancy for UTI?
amoxicillin
cefalexin
co-amoxiclav
antibiotics if complicated UTI/ urosepsis
gentamicin unless poor renal function, then temocillin
what is abacterial cystitis/urethral syndrome?
symptoms of UTI with pus cells but no growth on culture
causes of abacterial cystitis/urethral syndrome?
early phase UTI
urethral trauma (honeymoon cystitis)
chlamydia/gonorrhoea
management of abacterial cystitis/urethral syndrome?
alkalinise urine for symptomatic relief
what is asymptomatic bacteriuria?
significant bacteriuria but patient is asymptomatic
antibiotics not required unless pregnant
