id: uti Flashcards
Enterobacteriacae
gut gram -ve bacilli:
- E.coli
- Klebsiella
- Proteus
pathogenesis - 2 routes of infection
- ascending: colonic/fecal flora colonise periurethra area/urethra > ascend to bladder and kidney
- higher risk in females (shorter urethra), use of spermicides, diaphgrams as contraceptives
- gut bacteria - hematogenous (descending): organism at distant primary site eg. heart valve, bone > travels to bloodstream (bacteremia) > urinary tract > UTI
- S.aureus, Mycobacterium tuberculosis
host defense mech
- bacteria in bladder stimulates micturition with incr diuresis > emptying of bladder
- antibacterial properties of urine and prostatic secretion
- anti-adherance mechanisms of bladder, prevent attachment
- inflammatory response with PMNs > phagocytosis
risk factors for UTI
- female>male
- sexual intercourse
- abnormalities of the urinary tract eg. prostatic hypertrophy, kidney stones, urethral strictures, vesicoureteral reflux
- neurologic dysfunctions eg stroke, dm, spinal core injuries
- anticholinergic drugs
- catheterisation and other mechanical instrumentation
- pregnancy
- use of diaphragms and spermicides
- genetic association (pos fhx)
- previous uti
non-pharmaco for prevention of uti
- drink lots of fluid, flush the bacteria: 6-8 glasses a day
- urinate frequently and go when you first feel the urge, bacteria can grow when urine stays in the bladder too long
- urinate shortly after sex, flush away bacteria that might have entered the urethra during sex
- for women, after using the toilet, alw wipe from front to back esp after bowel movement
- wear cotton underwear and loose-fitting clothes so that air can keep the area dry, avoid tight-fitting jeans and nylon underwear which trap moisture and can help bacteria grow
- modify birth control method: stay away from diaphgram or spermicide, unlubricated condoms or spermicidal condoms incr irritation which may help bacteria grow
presence of complicating factors
- men
- children, pregnant
- functional and structural abnormalities of urinary tract
- genitourinary instrumentation
- dm
- immunocompromised host
lower UTI subj sx
- dysuria: pain
- urgency
- frequency
- nocturia
- suprapubic heaviness or pain
- gross hematuria
upper UTI subj sx
- fevers
- rigors
- headache
- n/v
- malaise
- flank pain
- costovertebral tenderness (renal punch)
- or abdominal pain
when to obtain cultures
- pregnant women
- recurrent uti (relapse within 2 weeks or freq)
- pyelonephritis
- catheter-associated uti
- all men with uti
not necessary in uncomplicated cystitis
objective signs (UFEME)
- WBC>10/mm3: pyuria, signifies presence of inflammation but may or may not be due to infection
- RBC, presence: hematuria: non-specific
- microorg: identify bacteria or yeast strain using gram stain
- WBC casts: masses of cells and proteins that form in the renal tubules in kidneys, indicate upper tract infection or disease
objective signs (chemical urinalysis/dipstick)
- nitrite: gram neg, reduces nitrate to nitrite
(false neg results due to presence of gram pos org and P.aeruginosa, low urinary pH, freq voiding and dilute urine) - leukocyte esterase: presence of leukocytes in urine, correlates with significant pyuria
likely pathogen for uncomplicated uti
85%: E.coli
5-15%: Staphylococcus saprophyticus, common coloniser of urinary tract
Others: Enterococcus faecalis (+ve), klebsiella, proteus
likely pathogen for complicated or healthcare-associated uti
50% E.coli
Enterococci (+)
Proteus, klebsiella, enterobacter (-v), p.aeruginosa
healthcare-assoc risk factors
- hospitalisation in the last 90 days
- current hospitalisation >= 2 days
- residence in nursing home
- antimicrobial use in last 90 days
- home infusion therapy
S.aureus
commonly due to bacteremia, consider other primary site of infection
Yeast or candida
possible contaminant, consider other primary site of infection
need to treat UTI?
yes if symptomatic
no if asymptomatic, except for:
- pregnant women: treatment reduces development of pyelonephritis and risk of preterm labour and low birth weight infant
- patients going for invasive urologic procedures with mucosal trauma eg. TURP cystoscopy with bipsy: abx given as prophylaxis to prevent postoperative bacteremia and sepsis > obtain culture then start abx based on culture and sensitivity 12-24hrs before procedure