Antimicrobial resistance patterns of gram-negative bacteria isolated from urine cultures at a general hospital

Abstract EN

To evaluate the antimicrobial resistance patterns of the Gram-negative organisms isolated from urine culture, we retrospectively analyzed the urine cultures and antibiotic sensitivity tests of inpatients and outpatients in our hospital between 1999 and 2002.

A total of 11,659 urine specimens were analyzed of which 2054(17.6%) showed significant growth; 1764 (85.9%) were Gram-negative organisms.

The most frequently isolated Gram-negative organisms were Escherichia coli 1026 (58%) and Klebsiella pneumoniae 293 (16.6%).

The resistance rates for strains of E.

coli isolated from the hospitalized patients were 61% to amoxicillin, 35% to amoxicillin-clavulanate, 47% to trimethoprim, 38% to ciprofloxacin, 31% to cephalexin and 13% to gentamicin.

These rates were higher than those from the outpatients (52%, 36%, 40%, 32%, 29% and 5%), respectively.

Out of the 42(2%) multidrug resistant E.

coli and K.

pneumoniae, 23(1%) were found to be positive for extended spectrum beta lactamase (ESBL) including 14 isolates of E.

coli and 9 of K.

pneumoniae.

We conclude that our findings demonstrate a significant increase of resistance to various groups of antimicrobial drugs in the urine culture isolated from both inpatients and outpatients.