Urinary Tract Infection

Dr. Ashish Jawarkar, M.D.

Urinary tract

Urinary Tract Infection

Upper urinary tract Infections: Pyelo-nephritis Ureteritis

Lower urinary tract infections Cystitis (“traditional” UTI) Urethritis (often sexually-transmitted)

Ascending UTI

Descending infection

Hematogenous spread Chronically ill or immunosuppressed

patients

Causes

Stasis of urine (enlarged prostate etc.) Sexual activity Pregnancy Catheterisation Stones

5-7% pregnant women may present without symptoms

May lead to prematurity and perinatal death

Hence mandatory to screen all pregnant women

Symptoms of Urinary Tract Infection

UPPER UTI Dysuria (burning micturition) Increased frequency

LOWER UTI Fever Flank pain

Agents of UTI

Most common – E coli Community acquired

E. coli Enterobacter

Hospital acquired Klebsiella S. aureus Pseudomonas

Lab diagnosis

Urine can get contaminated while passing

Sterile wide mouthed containerMid stream clean catch specimen First portion – bacteria from distal

urethra Processed within 2 hours

Significant bacteriuria

>1,00,000 bacteria per ml Counts <1000 are due to contamination Counts between 1000 and 1,00,000 may

be significant, have to be co related clinically and by repeat culture

Other methods for collection

Suprapubic aspiration

Percutaneous nephrostomy

catheter

Culture

Blood agarMc conkey agar

Antibiotic susceptibility testing

Screening tests

Nitrite test TTC test Demonstration of bacteria in wet film

Wet mount

Strips

Family enterobacteria

Include E. coli Klebsiella Proteus

Escherichia Coli

Named after Escherich who first discovered the colon bacillus

Lives in intestine, passed in feces

Test for contaminated water supply

E coli testing in water

Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment

Morphology

Gram negative rod Singly or in pairsMotile

Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment

Growth characteristics

Good growth on ordinary media Hemolytic on blood agarMac conkeys agar, pink colonies

Blood agar

Mac conkey’s medium

Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment

IMViC test

I - IndoleM - Methyl red Vi - Voges-Proskauer C - Citrate utilisation

To differentiate between enterobacteria

Klebsiella IMViC

Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment

Resistance

Resistant to multiple antibiotics Due to production of beta lactamase

which inactivates penicillin and cephalosporins

Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment

Pathogenicity and virulence

Surface antigens O and K O antigen – prevents phagocytosis,

endotoxic activity K antigen – also protects against

phagocytoisis Fimbria – important in UTI Toxins – beta lactamase

Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment

Epidemiology

Inhabit the colon Spread via contaminated water/food

Diseases caused

UTI Precipitated by

Prostate enlargement Pregnancy Calculi

Peritonitis and bowel abcessesMeningitis in new born Septicemia

Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment

Treatment

Ampicillin + clavulanic acid ImipenemMeropenem