UTI Flashcards
What is Asymptomatic Bacteriuria(ASB)?
isolation of significant colony counts of bacteria in the urine(bacteriuria) from a person WITHOUT symptoms of UTI
Screening and treatment of ASB is only indicated for ______ populations
1) Pregnant women [2-7%]
2) Patients going for urological procedure in which mucosal trauma/bleeding is expected [eg. TURP, cystoscopy with biopsy]
When and Why do pregnant women screen and treat ASB?
To prevent pyelonephritis, preterm labor and infant low birth weight
Screen at one of the first visits(12-16 weeks gestation)
- Do urine culture
- If bacteriuria, treat with active antibiotics(based on AST) for 4-7 days
When and Why do screen and treat ASB?
To prevent postoperative bacteremia and urosepsis
Screen prior to procedure — 2-3 days before
- If bacteriuria, use active antibiotics as surgical antibiotic prophylaxis(SAP)(based on AST)
Does not include placement of a urinary catheter
Epidemiology of UTI
Increasing from young to old
* 0-6 mths: males > females
* 1-adult: females > males
* Elderly(age>65): equal
What are the 2 routes of infection of UTI
- Ascending [most common]
* colonic/fecal flora colonise periurethral area/urethra → ascend to bladder & kidney
* Gram-negative bacilli (E.coli/Klebsiella/Proteus) - Hematogenous(descending)
* Organism at distant primary site(heart/bone) → bloodstream(bacteremia) → urinary tract → UTI
* S.aureus, TB
What are the factors determining the development of UTI?
1) Competency of the natural host defense mechanisms
- bacteria stimulate micturition(increase urge of emptying bladder)
- antibacterial properties of urine and prostate secretions
- anti-adherence mechanism of bladder(prevent bacteria attachment)
- Inflammatory response by leukocytes → phagocytosis
2) Size of the inoculums(load of bacteria that is present at the site of infection)
3) Virulence/pathogenicity of the microorganism
What are the risk factors of UTI?
- Gender(Female > male)
- Sexual intercourse
- Abnormalities of the urinary tract (prostatic hypertrophy, kidney stones, urethral strictures, vesicoureteral reflux)
- Neurological dysfunctions (stroke, DM, spinal cord injuries)
- Anticholinergic drugs (SE: urinary retention)
- Catheterization and other mechanical instrumentation
- Diabetes
- Pregnancy
- Use of diaphragms & spermicides
- Genetic association(positive family history)
- Previous UTI
NPM of UTI
1) Drink lots of fluid to flush bacteria
2) Urinate frequently
3) Urinate shortly after sex
4) Wipe from front to back
5) Wear cotton underwear and loose-fitting clothes so that air can keep the area dry
6) Those on diaphragm/spermicide as birth control: consider modifying your birth control method
* Unlubricated condoms or spermicidal condoms increase irritation(grow bacteria)
What are considered complicated UTI?
- UTI in men, children and pregnant women
- Presence of complicating factors:
1) Functional/structural abnormalities or urinary tract
2) genitourinary instrumentation
3) DM
4) immunocompromised host
Symptoms of cystitis(LUTI)
- Dysuria(pain on urination)
- Urgency
- Frequency
- Nocturia
- Suprapubic heaviness or pain
- Gross hematuria
Symptoms of pyelonephritis(UUTI)
- Fever, malaise
- Rigors
- Headache
- Nausea and vomiting
- Flank pain
- Costovertebral tenderness(renal punch)
- Abdominal pain
Microscopic urinalysis(UFEME: urine formed elements and microscopic examination) tests for?
White blood cells(WBC)
* >10 WBCs/mm3 = pyuria
* Signifies presence of inflammation(may or may not be due to infection. If symptomatic, pyuria correlates with significant bacteriuria
* Absence of pyuria = unlikely UTI
Red blood cells(RBC)
* Presence(microscopic >5/HPF or gross) = hematuria
* Frequently occurs in UTI but non-specific
Microorganisms
* Identify bacteria or yeast using gram-stain
WBC casts
* Masses of cells and proteins that form in renal tubules(kidneys)
* Indicates upper tract infection/disease
if there is presence of squamous epithelial, urine might have been contaminated
What are the 2 Chemical urinalysis(dipstick) tests?
What do they test for?
1. Nitrate
- Positive test detects presence of gram-negative bacteria
- Only gram negative bacteria reduces nitrate to nitrite
- Requires at least 10^5 bacteria/ml
- False-negative results due to presence of gram-positive organisms and P.aeruginosa, low urinary pH, frequent voiding and dilute urine
2. Leukocyte esterase(LE)
- Positive tests detects esterase activity of leukocytes in urine
- Correlates with significant pyuria(>10 WBCs/mm3)
When is urine culture(pre-treatment culture) required?
- Pregnant women
- Recurrent UTI(relapse within 2 weeks or frequent)
- Pyelonephritis
- Catheter-associated UTI
- All men with UTI
Not need for urine culture in uncomplicated cystitis
What are the likely pathogens for uncomplicated/community-acquired UTI?
- Escherichia coli(>85%)
- Staphylococcus saprophyticus(5-15%)
- Enterococcus faecalis
- Klebsiella pneumoniae
- Proteus spp
What are the likely pathogens for complicated/healthcare-associated UTI?
- Escherichia coli(~50%)
- Enterococci
- Proteus spp
- Klebsiella spp
- Enterobacter spp
- P.aeruginosa
HA risk factors: recent/frequent exposure to healthcare settings
(last 90 days, current>/=2days, nursing home)
____ commonly causes UTI from bacteremia
____ causes UTI by acting as a possible contaminant
S.aureus
Yeast/Candida
When do you treat UTI positive culture with antibiotics?
NO if ____
YES if ____
- NO if patient does not have symptoms of UTI but positive culture(ASB) except for Pregnant women & patients going for urologic procedure in which mucosal trauma/bleeding is expected
- YES if patients is symptomatic(urinary symptoms) or any of the 2 exceptions above
What are the first line empiric abx for cystitis in women?
- PO Co-trimoxazole 800/160 mg bid x 3d (2 tablets)
- PO Nitrofurantoin 50mg qid x 5d
- PO Fosfomycin 3g single dose
Alternatives:
- PO beta-lactams x 5-7 days
- PO cefuroxime 250 mg bid
- PO amoxicillin-clavulanate 635 mg bid
- PO cephalexin 250-500mg qid(rising resistance)
- PO fluroquinolones x 3 days
- PO ciprofloxacin 250 mg bid
- PO levofloxacin 250 ng daily
Collateral damage is high, ONLY oral for pseudo
What are the first line empiric abx for Complicated Cystitis in women?
- Same as uncomplicated cytitis in women BUT
- Treat for longer duration (7-14 days)
- Fosfomycin PO 3g EOD x 3 doses
What are the first line empiric abx for Community-acquired pyelonephritis(kidney) in women?
- PO fluoroquinolones
- PO ciprofloxacin 500mg twice daily x 7 days
- PO levofloxacin 750mg daily x 5 days
What are the 2nd and 3rd line empiric abx for Community-acquired pyelonephritis(kidney) in women?
2nd line: PO co-trimoxazole 160/800mg twice daily x 10-14 days
3rd line: PO beta-lactam x 10-14 days
- PO cefuroxime 250-500 mg bid
- PO amoxicillin-clavulanate 625mg tds
- PO cephalexin 500mg qid
What are the empiric abxs for Community-acquired pyelonephritis(kidney) in women?
that are severely ill;require hospitalization[AG not good if bacteremia]
OR
unable to take oral drugs
- Initial intravenous(IV) therapy
- IV ciprofloxacin 400mg bid
- IV cefazolin 1g q8h
- IV amoxi-clav 1.2g q8h
**AND/OR ** - IV/IM gentamicin 5mg/kg
- To cover low % of ESBL ecoli/klebsiella in the community
Switch to oral when patient improved or able to take orally
- Initial empiric therapy should be modified when result of urine culture and susceptibility becomes available(->definitive/culture-directed therapy)
