Klebsiella pneumoniae: epidemiology and analysis of risk factors for infections caused by resistant strains.

OBJECTIVE: To analyze the epidemiology of hospital and community-acquired infections caused by Klebsiella pneumoniae (K. pneumoniae) and risk factors for infections caused by resistant strains.

METHODS: A retrospective observational study was performed to analyze the relationship between antimicrobial use and bacterial resistance.

RESULTS: A K. pneumoniae infection was diagnosed in 0.47% of patients (169 of 36 179) admitted to the hospital between 1 March 1999 and 31 August 2000. Of the 169 isolates, 166 (98.2%) were resistant to at least one antimicrobial and 91.1% (154/169) to two or more antibiotics. 98% were resistant to ampicillin, 77% to piperacillin, 64% to cephalothin, 60% to ampicillin/sulbactam, 59% to cefoperazone, 57% to cefazolin, 55% to cefuroxime, 51% to TMP-SMZ, 51% to tobramycin, 50% to gentamicin, 49% to aztreonam, cefetaxime and ceftriaxone respectively, 47% to ceftazidime, 47% to cefepime, 46% to ciprofloxacin, 46% to ticarcillin/clavulanate, 44% to amikacin, 38% to cefoxitin, 22% to piperacillin/tazobactam, while all strains were tested susceptible to imipenem.

CONCLUSIONS: Prior receipt of amtimicrobial therapy was significantly associated with infection caused by a resistant organism and most strains were resistant to multiple antibiotics.