Multidrug Resistant in Nosocomial Urinary Tract Infections at a Tertiary Care Hospital in Kerala, India

Nosocomial UTI (NUTI) is a major cause of morbidity in hospitalized patients and presence of urinary catheter is its single most important predisposing factor. Antibiotic resistance is a problem in these infections.

To estimate the prevalence of NUTI in our setting, identify the predisposing factors and etiological agents of NUTI; to determine the antibiotic susceptibility patterns of the pathogens; to identify the risk factors for the acquisition of antibiotic resistance in these patients and to study the effect of duration of catheterization on the nature of infection.

After identifying suspected cases of NUTI based on signs and symptoms, relevant clinical details were noted and the urine samples were collected aseptically and cultured on blood agar and MacConkey’s agar using the calibrated-loop-semi-quantitative method. Isolates from samples with significant bacteriuria were identified. Antibiotic susceptibility test was performed using modified Kirby-Bauer disk diffusion method. Resistance of the isolates to fluoroquinolones and third generation cephalosporins was confirmed by minimum inhibitory concentration (MIC) using agar dilution method for ciprofloxacin and cefotaxime respectively.

Catheterization was the most common (88.1%) predisposing factor for NUTI. was the most common single isolate, accounting for 96 (41.2%) of the total 233 isolates. Multidrug resistance was observed in 81 (84.37%) of isolates. High rates of resistance were found with ampicillin (91.66%), ciprofloxacin (75%), cotrimoxazole (71.87%), cefuroxime (82.29%), cefotaxime (79.16%), cefepime (67.7%) and amoxicillin/clavulanate (63.54%) among the E. coli isolates. However, imipenem (0% resistance), meropenem(0%), piperacillin-tazobactam (15.62%), amikacin (5.2%) and nitrofurantoin (26.04%) appeared to have retained greater activity.

Considering the high rates of resistance found with fluoroquinolones, ampicillin, cotrimoxazole and cephalosporins, these can no longer be recommended for empiric therapy of NUTIs. Instead, imipenem, pipericillintazobactam, amikacin and nitrofurantoin should be considered for initial therapy with prompt de-escalation following receipt of the culture and sensitivity result.