ASB/UTI Flashcards
Antibiotics indicated for ASYMPTOMATIC bacteriuria
NONE
UNLESS pts show signs of systemic infection & delirium
*in elderly: bacteruria & delirium independently common
Bacteriuria definition
presence of significant colonies of bacteria in urine
When to screen for asymptomatic bacteriuria?
- pregnant women - screen @ one of first visits (12-16wks gestation)
- prevent pyelonephritis, preterm labor, low infant birth weight
- IF ASB: treat with active abx BASED ON AST; duration 4-7d - patients undergoing urologic procedure (where mucosal trauma/ bleeding expected)
- IF ASB: use active abx as SAP
Difference between ASB & UTI
UTI: pts are SYMPTOMATIC (have urinary symptoms)
ASB: pts are ASYMPTOMATIC
Prevalence of UTI
0-6months: M > F
1y - adult: F > M
Elderly (>65y): equal
Pathogenesis of ascending type of UTI
Type of pathogen: Enterobacteriaceae (E.coli/ Klebsiella/ Proteus)
- Colonic/ fecal flora colonise (peri)urethra area -> ascend to bladder & kidney
*HIGHER RISK in females (shorter urethra) // use of spermicides & contraceptives
Pathogenesis for descending (hematogenous) type of UTI
*more rare
Type of pathogen: S. aureus, M. tuberculosis
Bacteria from distant site eg. heart valve/bone enters BLOODSTREAM *bacteremia -> urinary tract -> UTI
Factors in determining development of UTI
- Host defence mechanisms
- Bacteria in bladder stimulates micturition with increased diuresis -> emptying of bladder
- Antibacterial properties of urine & prostatic secretion
- Anti-adherence mechanisms of bladder mucosa (prevent bacterial attachment to bladder)
- Inflammatory response w polymorphonuclear (PMN) leukocytes -> phagocytosis -> prevent/ control spread - Size of inoculum -> increased risk with obstruction/ urinary retention
- virulence/ pathogenicity of microorganism eg. E.coli: presence of pili -> resistant to washout/ removal by antiadherence mechanisms of bladder
Risk factors for development of UTI
- F > M
*pregnancy, use of spermicides & diaphragms - Sexual intercourse
- Structural abnormalities of urinary tract
- Neurologic dysfunctions (Stroke, DM, Spinal cord injury)
- Anti-cholinergic drugs (1st gen antihistamine S/E urinary retention)
- Catheterisation & other mechanical instrumentation
- Diabetics
- Genetic association
- Previous UTI
Counseling points on preventing UTI
- HYDRATION (flush bacteria) - 6-8 glasses a day (unless fluid restricted)
- Urinate frequently
- Urinate shortly after sex
- (Women) wipe from front to back
- Wear cotton underwear/ loose clothing to air the area (keep dry)
- Modify birth control method (X spermcides/ lubricated condoms: increase irritation -> promote bacterial growth)
Types of UTI
- Complicated vs uncomplicated
- Uncomplicated: UTI that occurs in healthy premenopausal, non-pregnant women with NO history suggestive of an abnormal urinary tract
- Complicated: everything else; suggests INCREASED potential for serious outcomes/ risk for therapy failure (needs longer therapy duration) - Upper vs Lower UTI
- UPPER: pyelonephritis
*systemic symptoms (fever/ malaise/ headaches/ +ve renal punch/ flank pain/ UFEME: +ve WBC casts
- LOWER: cystitis
*urinary symptoms: dysuria, urgency, urinary frequency, nocturia, suprapubic heaviness/ pain, gross hematuria
Clinical presentation for UTI
Subjective
- Lower UTI: urinary symptoms (dysuria, urgency, urinary frequency, nocturia, suprapubic heaviness/pain, gross hematuria)
- Upper UTI *kidney infected: systemic symptoms (fever, headache, nausea/vomiting, malaise, flank pain, +ve renal punch, abdominal pain)
Objective
- Urinalysis - UFEME // culture
*urine to be collected via midstream CLEAN-catch/ catheterisation/ aspiration of suprapubic bladder
UFEME:
WBC (> 225 OR 10/mm3) -> PYURIA *not specific for infection; if NO pyuria -> UNLIKELY UTI
RBC (>5) -> hematuria
Microorganisms * Gram stain
WBC casts *specific for UPPER UTI
- Dipstick
1. Nitrite - if +ve -> Gram -ve bacteria (reduces nitrate to nitrie) *requires at least 10^5 bacteria/ml
**false +ve: S. aureus & P. aeruginosa, low urinary pH, frequent voiding, dilute urine
2. Leukocyte esterase -> indicates presence of WBC in urine (esterase activity of leukocytes) -> significant pyuria (>10 WBC/mm3) - Culture:
*NOT needed if uncomplicated cystitis
pre-treatment culture for: pregnant women/ recurrent UTI (relapse <2wks/ frequent)/ pyelonephritis/ CA-UTI/ all men w UTI)
Likely pathogen for UTI
uncomplicated: E. Coli (>85%); S. saprophyticus (5-15%); Gut enterobactericeae (Enterococcus faecalis, Klebsiella pneumoniae, Proteus spp.)
Complicated/ HA-UTI: E. Coli (~50%), Proteus/ Klebsiella/ Enterobacter / P. aeruginosa
Others: S. aureus (often due to bacteremia -> consider other PRIMARY sites of infection), yeast (candida) *possible contaminant -> consider other sites of infection
Antimicrobial regimen for UNCOMPLICATED vs COMPLICATED CYSTITIS in WOMEN
UNCOMPLICATED
- Nitrofurantoin 50mg QID x5d (*CI if CrCl <30ml/min)
- Fosfomycin 3g single dose *reserve for ESBL, not 1st line
- Co-trimoxazole 800/160mg (double strength) BD x 3d
Alternatives: beta-lactams (5-7d)
- cefuroxime 250mg BD
- amoxi-clav 625mg BD
- cephalexin 250-500mg QID
FQ (3d) *avoid if possible
- cipro 250 BD
- levo 250 OD
if COMPLICATED - treat for longer duration (7-14d)
*fosfomycin dose: fosfomycin 3g every other day x3 doses
treatment for community-acquired PYELONEPHRITIS in women
1st line: Fluoroquinolones
- PO Cipro 500mg BD x7d
- PO Levo 750 OD x 5d
- PO co-trimoxazole 800/160mg BD x10-14d
Beta-lactams x10-14d
- Cefuroxime 250-500mg BD
- Amoxi-clav 625mg TDS/ q8h
- Cephalexin QID
*if severely ill/ unable to take oral -> IV
- IV cipro 400mg BD
- IV cefazolin 1g q8h
- IV amoxi-clav 1.2g q8h
AND/OR
- IV/IM gentamicin 5mg/kg (good for GNR, ESBL; concentrates in UT)
*AGs: not v good for bacteriuria (NOT for monotherapy) -> add-on cipro/cefa/amoxi-clav
**if bacteria is ESBL: usually resistant to FQs, cefazolin & amoxi-clav also usually not susceptible
Switch back to oral when pt improves/ able to take PO
Treatment for community-acquired UTI in MEN (cystitis, pyelonephritis)
*if no concern for prostatitis (no pain)
- treat as per complicated cystitis for women
(longer duration of 7-14d)
- nitro 50mg QID
- co-trim 800/160mg BD
- fosfomycin 3g EOD x3 doses
-beta lactams (cefuroxime 250mg BD/ amoxi-clav 625mg BD/ cephalexin 250-500mg QID)
- FQs (cipro 250mg BD/ levo 250mg OD)
** IF concern with prostatitis OR PYELONEPHRITIS
- PO cipro 500mg BD
- PO co-trimoxazole 800/160mg BD
Duration: 10-14d BUT if prostatitis confirmed: 6 weeks
nosocomial/ HA-UTI occurrence, possible pathogen
Onset: after 48h past hospital admission
Pathogen: possibility of more resistant bacteria -> P. aeruginosa, ESBL, Klebsiella
*BROAD-spectrum beta-lactam for empiric therapy
Empiric therapy for HA-UTI
- IV cefepime 2g q12h +/- IV amikacin 15mg/kg OD (amikacin to cover for ESBL)
- IV Imipenem 500mg q6h
- IV Meropenem 1g q8h
*if able to take oral/ less sick:
- PO cipro 500mg BD
- PO levo 750 OD
Duration: 10-14d
Definition of catheter-associated UTI
Presence of symptoms/ signs compatible w UTI with NO other identified source of infection/ 10^3 cfu/ml of at least 1 bacterial species in a single catheter urine specimen
*pts with indwelling urethral/ suprapubic/ intermittent catheterisation/ in midstream voided urine specimen from patient w catheter removed within 48h
Risk factors for CA-UTI
- duration of catheterisation (<7d/short-term: single organism; >28d/long-term: polymicrobial)
- diabetes
- female
- renal function impairment
- Colonisation of drainage bag/ catheter/ periurethral segment
- Poor quality of catheter care, including insertion
Clinical presentation/ antibiotic indication for treatment of CA-UTI
- if pt has asymptomatic bacteriuria: treatment NOT recommended (except prior to traumatic urological procedure)
*consider removal of catheter; if catheter is still indicated -> REPLACE catheter
SYMPTOMATIC infection:
new onset/ worsening of fever/ rigors/ altered mental status/ malaise/ lethargy with NO OTHER IDENTIFIED CAUSE// flank pain/ +ve renal punch/ acute hematuria/ pelvic discomfort
**if patient stable + low-grade fever -> consider observation first
**URINE +/- BLOOD CULTURE MUST BE TAKEN BEFORE ABX GIVEN
[Empiric therapy: as per HA-UTI]
- IV cef 2g q12h +/- IV amikacin 15mg/kg OD
- IV imi 500mg q6h // IV mero 1g q8h
- **PO/IV levo 750mg OD x 5d mild CA-UTI
- **PO co-trim 800/160mg BD x3d *women =/<65 w CA-UTI W/O upper UTI symptoms AFTER indwelling catheter removed
Duration of therapy: 7d (if prompt resolution of symptoms/ fever gone in 72h), ELSE if delayed response 10-14d
chronic suppressive therapy NOT recommended
topical/prophylactic (prevention) abx NOT recommended
Management of UTI in pregnant women
- AVOID cipro
- AVOID co-trimoxazole in 1st & 3rd trimester (risk of kernicterus, concern for fetus being G6PD-deficient)
- AVOID nitrofuration if (38-42weeks)
- AGs: USE WITH CAUTION
- fosfomycin: crosses placenta, use if benefit > risk (BUT dont use if risk of preterm labour)
1st line: beta-lactams
* if ASB/ cystitis -> 4-7d
* if pyelonephritis -> 14d
Adjunctive therapy for UTI (pain, fever, vomiting, urinary symptoms)
Pain/fever -> paracetamol, NSAIDs
Vomiting -> rehydration
Urinary symptoms:
1. PHENAZOPYRIDINE 100-200mg TDS
azo dye w analgesic effect on UT mucosa -> symptomatic relief
**only take when symptoms are present
** CI: G6PD deficient // ADR: N/V, orange-red discolouration of urine & stool
- urine alkalinisation - relief discomfort in mild UTI (not proven)
- Cranberry juice - inhibit adherence of E. coli to UT epithelial cells (insuff evidence)
- Intravaginal estrogen cream *controversial
*lowers UTI incidence in postmenopausal women (Restore vaginal flora, prevent E.coli colonisation) - Lactobacillus probiotics: restore normal vaginal flora + protective effect against E.coli colonisation
*intravaginal lactobacillus LOWERS recurrence of uncomplicated cystitis
Monitoring treatment for UTI
- Resolution of symptoms
*improvement/ resolution by 24-72h after initiation of effective abx
**if pt does not respond within 2-3d OR persistently +ve blood/urine culture -> further investigate: bacterial resistance/ possible obstruction/ renal abscess/ other disease process? - Bacteriological clearance
*repeat culture NOT NEEDED if pts respond to treatment
** PREGNANT WOMEN culture needed to document clearance of infection - Absence of ADR & allergies
when is pre-treatment culture required for uti?
pregnant women
recurrent uti (relapse within 2 weeks/ frequent)
pyelonephritis
CA-UTI
men w UTI
