Urinary Tract infections

1. Urinary Tract Infections
Lourdes Lozano Vargas
2/26/2009

2. Urinary Tract Infections
 Leading cause of morbidity and health
care expenditures in persons of all ages.
 An estimated 50 % of women report
having had a UTI at some point in their
lives.
 8.3 million office visits and more than 1
million hospitalizations, for an overall
annual cost > $1 billion.

3. Acute Uncomplicated Cystitis
 Sexually active young
women.
 Causes: anatomy and
certain behavioral factors,
including delays in
micturition, sexual activity,
and the use of diaphragms
and spermicides tract.
 Aggressive diagnostic
work-ups are unwarranted
in young women
presenting with an
uncomplicated episode of
cystitis.

4. Acute Uncomplicated Cystitis
 The microbiology is limited
to a few pathogens.
 70%- 85% are caused by
Escherichia coli
 5-20%are caused by
coagulase-negative
Staphylococcus
saprophyticus
 5-12% are caused by other
Enterobacteriaceae such
as Klebsiella and Proteus.

5. Acute Uncomplicated Cystitis
 Clinical Features:
dysuria, frequency,
urgency, suprapubic
pain, hematuria.
 Fever >38C, flank
pain, costovertebral
angle tenderness,
and nausea or
vomiting suggest
upper tract infection.

6. Acute Uncomplicated Cystitis
 Diagnosis: direct history and PE
 PE: Temperature, abdominal exam,
assessment of CVA tenderness, pelvic
exam.
 H/o STD’s, new sexual partner, partner
with urethral symptoms, gradual onset.

7. Acute Uncomplicated Cystitis
 Guidelines for tx of acute cystitis
recommend empiric antibiotic tx.
 Unnecessary antibiotic use??
 Clinical criteria for Dx:
Dysuria, presence of > trace urine leukocytes,
and presence of nitrites or...
Dysuria and frequency in the absence of
vaginal discharge.

8. Acute Uncomplicated Cystitis
 UA: Evaluation of midstream urine for pyuria.
 White blood cell casts in the urine are Dx of upper
tract infection.
 Urine Culture: Not necessary
 Warranted in: Suspected complicated infection,
persistent symptoms following tx, symptoms recur
< 1 mo after tx.

9. Acute Uncomplicated Cystitis
 Urine dipsticks:
 Leukocyte esterase (pyuria), sensitivity 75-90%,
specificity 95%
 Nitrite (Enterobacteriacea), sensitivity 35-85%,
specificity 95%, false positive with
phenazopyridine, beets.
 Microscopic evaluation for pyuria or a culture is
indicated in pt with negative leukocyte esterase
that have urinary symptoms.

10. Acute Uncomplicated Cystitis
 Susceptibility:
 E.coli
 30% isolates resistance to ampicillin and sulfonamides
 Increasing of resistance to TMP-SMX
 Resistance to nitrofurantoin is <5%
 Resistance to fluoroquinolones <5%
 S.saprophyticus
 3% resistant to TMP-SMX
 0% resistant to nitrofurantoin
 0.4% resistant to ciprofloxacin

11. Acute Uncomplicated Cystitis
 Treatment:
 Short course vs. prolonged tx
 Short course preferred except with beta-lactam
agents
 TMP-SMX (160/800mg BID x 3) first-line tx
if: no allergy to the drug, no antibiotics in the past
3 mo, no recent hospitalization.
 Nitrofurantoin (100mg BID x 5 days)
 Analgesia: Phenazopyridine 200mg TIDx2

12. Acute Urethral Syndrome
 Acute symptomatic women with dysuria
and frequency with a midstream culture
containing < 10(5) CFU/mL.
 > 10(2) CFU/mL in women with acute
symptomatic pyuria = UTI
 Tx as an uncomplicated UTI
 Mycoplasma genitalium, Ureaplasma
urealyticum

13. Acute Complicated Cystitis
 UTI when/with structural, functional or metabolic
abnormalities (polycystic, solitary, transplant
kidney;DM, CRF, indwelling cath, neurogenic
bladder) or elderly, male, child, pregnant or h/o
recurrent UTI)
 E.coli accounts for fewer than one third of
complicated cases.
 Clinically, the spectrum of complicated UTIs may
range from cystitis to urosepsis with septic shock.

14. Acute Complicated Cystitis
 Urine culture and susceptibility are necessary.
 These infections are usually associated with high-
count bacteriuria (> 10(5) CFU/mL).
 MO: Proteus, Klebsiella, Pseudomonas, Serratia, and
Providencia, enterococci, staphylococci and fungi
AND E.coli

15. Acute Complicated Cystitis
 Empiric therapy for these patients should include an
agent with a broad spectrum of activity against the
expected uropathogens: fluoroquinolone,
ceftazidime, cefepime, aztreonam, imipenem-
cilastatin. (Obtain Ucx prior to Tx)
 Tx x 7-14 days
 Follow-up urine culture should be performed
within 14 days after treatment???

16. Recurrent Cystitis
 Up to 27% of young women with acute cystitis
develop recurrent UTIs.
 The causative organism should be identified
by urine culture.
 Relapse: infection with the same organism
(multiple relapses = complicated UTIs).
 Recurrence: infection with different
organisms.

17. Recurrent Cystitis
 >3 UTI recurrences documented by urine Cx within
one year can be managed using one of three
preventive strategies:
1. Acute self-treatment with a three-day course of
standard therapy.
2. Postcoital prophylaxis with one-half of a TMP-SMX
double-strength tablet (80/400 mg).
3. Continuous daily prophylaxis TMP-SMX one-half
tablet per day (40/200 mg); nitrofurantoin 50 to 100
mg per day; norfloxacin 200 mg per day.

18. Uncomplicated Pyelonephritis
 Suspect if:
 Cystitis-like illness and accompanying flank
pain
 Severe illness with fever, chills, nausea,
vomiting, abdominal pain
 Gram-negative bacteremia.

19. Uncomplicated Pyelonephritis
 DX: Clinical, confirm with:
 UA: pyuria and/or WBC casts
 UCx with > 10 (5) CFU/mL (80%)
 Tx: 14 days total
 Oral: TMP/SMX, fluoroquinolones
 IV: 3rd gen cephalosporin, aztreonam,
quinolones, aminoglycoside

20. Uncomplicated Pyelonephritis
 Pt with symptoms after 3 days of
appropriate antimicrobial tx should be
evaluated by renal US or CT for
obstruction or abscess.

21. UTI in Men
 At risk: Older men with prostatic
disease, UT instrumentation, anal sex,
or partner colonized with uropathogens.
 UCx: 10 (3) CFU/mL sensitivity and
specificity 97%.
 Additional studies?
 Not necessary in young healthy men who
have a single episode.

22. UTI in Men
 Tx:
 Uncomplicated cystitis:
 TMP/SMX or fluoroquinolones x 7 days
 Complicated cystitis:
 Fluoroquinolones x 7-14 days
 Bacterial prostatitis:
 Fluoroquinolone x 6-12 weeks

23. Catheter-Associated UTI
 Risk of bacteriuria is ~ 5%/day (long
term catheter bacteriuria is inevitable).
 40% of nosocomial infections
 Most common source of gram-negative
bacteremia.
 Dx: Ucx 10 (2) CFU/mL
 MO: E.coli, Proteus, Enterococcus,
Pseudomona, Enterobacter, Serratia,
Candida

24. Catheter-Associated UTI
 Mild to mod: oral quinolones10-14days
 Severe infection: IV/oral 14-21days
 Asymptomatic bacteriuria in pt with
an indwelling Foley should not be Tx
unless they are immunosuppressed,
have risk of bacterial endocarditis or pt
who are about to undergo urinary tract
instrumentation.

25. Asymptomatic Bacteriuria
 UCx: > 10(5)CFU/mL with no symptoms
 Three groups of pt with asymptomatic
bacteruria have been shown to benefit
from tx:
 Pregnant
 Renal transplant
 Pt who are about to undergo urinary tract
procedures.

26. Pregnant patients
 Asymptomatic bacteriuria: two
consecutive voided urine specimens
with isolation of the same bacterial
strain >10(5) or a single cath urine
specimen.
 Nitrofurantoin 100mg BID x 5-7 days
 Amoxi/Clav 500mg BID or 250 TID x 7days
 Fosfomycin 3g PO x 1

27. Interstitial Cystitis
 Frequency, urgency, urge incontinence
with periurethral and suprapubic pain on
bladder filling that is improved by
voiding. Terminal hematuria may be
present.
 Etiology. Unclear (autoimmune, altered
glycosaminoglycal layer, allergic)

28. Interstitial Cystitis
 TX
 Refer to urology for cystoscopy.
 Dietary modifications
 Behavioral modifications
 Rx:
 Pyridium
 Pentosan polysulfate 100mg TID x 6mo to 2
years.
 Amitriptyline 10-75mg QHS

29. Interstitial Cystitis
 Intravesical therapies
 Dimethyl Sulfoxide instillations q1-2 wks
 BCG instilled q1wk x 6-8 wks
 Hyaluronic acid instilled q1wk x 4-6wk.

30. References
 Orenstein, Wong. Urinary Tract Infection in Adults. AAFP 1999;
 Hooton, Scholes, et al. A prospective study of risk factors for
symptomatic urinary tract infections in young women. N Engl J
Med 1996; 335:468.
 Hooton, Besser, et al. Acute uncomplicated cystitis in an era of
increasing antibiotic resistance: a proposed approach to
empirical therapy. Clinic Infect Dis 2004; 39:75.
 Stamm, Hooton. Management of urinary tract infections in
adults. N Engl J Med 1993; 329:1328.
 Hooton, Winter, et al. randomized comparative trial and cost
analysis of 3 day antimicrobial regimens for treatment of acute
cystitis in women.