Microbiology Flashcards
what is a UTI?
the presence of pathogens in the urinary tract
what are the two main types of UTI?
upper and lower
what is a complicated UTI?
one complicated by either systemic symptoms or urinary structural abnormalities/stones
what is bacteriuria?
bacteria in the urine
in what situations can bacteriuria often not mean infection?
elderly patients
catheter use
what is cystitis?
inflammation of the bladder - not always due to infection
what is the microbiological state of normal urine?
sterile
what bacteria is found at the lower end of the urethra?
commensals from the large bowel
coliforms, enterococci
which sex is more commonly affected by UTI’s and why?
women
have a short, wide urethra that is close to the anus
what are the two routes of infection in a UTI?
ascending - moves up the urethra
haematogenous
what is the most common causative pathogen of a UTI?
e coli
name three gram negative causative organisms of UTI
coliforms
proteus
pseudomonas aeruginosa
what are coliforms?
gram negative bacilli
name a coliform
e coli
what is a common complication of proteus sp UTI?
struvite stones
what is produced by proteus sp and what effect does this have in UTIs?
produces urease
breaks down urea to ammonia = increased urinary pH
what type of bacteria is pseudomonas aeruginoas?
gram negative bacillus
what is pseudomonas UTI associated with?
catheters
immunosuppression
what antibiotic can be used to manage UTI due to pseudomonas aeruginosa?
ciprofloxacin
how can ciprofloxacin be administered?
oral or IV
who should not receive ciprofloxacin?
young children
pregnant women
what is the mechanism of action of ciprofloxacin?
inhibits bacterial DNA gyrase
why is use of ciprofloxacin limited?
to reduce number of C Diff infections
what two gram positive organisms can cause UTI?
enterococcus
staphylococcus
what is the most common enterococcus in UTI?
enterococcus faecalis
what is enterococcus UTI often associated with?
hospital acquired infection
what staph is a cause of UTI?
staph saprophyticus
what are some common symptoms of UTI?
dysuria
frequency
nocturia
haematuria
what is dysuria?
pain when passing urine
what are some symptoms that suggest upper involvement in a UTI?
fever
loin pain
rigors
what type of urine specimen should be collected?
a midstream specimen of urine
what type of containers can be used for urine specimens?
boricon container
sterile universal container
what does a positive leucocyte on urinalysis show?
presence of leucocytes in the urine
what does positive nitrites on urinalysis show?
presence of bacteria in the urine
who should not have urinalysis for UTI done?
elderly
those with catheters
how can lab diagnosis of a UTI be done?
microscopy of urine
culture of urine
what criteria is applied to women of childbearing ge to determine if they have a UTI?
kass’s criteria
according to kass’s criteria, what suggests a probable UTI?
> 10x5 organisms/ml
how long should antibiotics be given for to women with uncomplicated lower UTI’s?
three days course
when would antibiotics be given for asymptomatic bacteriuria?
if pregnant
what is the empirical treatment for a female with a lower UTI?
nitrofurantoin or trimethoprim orally for 3 days
what is the empirical treatment for an uncatheterised male with a UTI?
get cultures
nitrofurantoin or trimethoprim for 7 days
what is the empirical treatment for an uncomplicated UTI or pyelonephritis
co-amoxiclav or co-trimoxazole for 7 days
what is the empirical treatment for a complicated UTI or pyelonephritis?
amoxicillin + gentamicin IV for three days
co-trim + gent if penicillin allergic
