Outbreak of a multiresistant Klebsiella pneumoniae strain in an intensive care unit: Antibiotic use as risk factor for colonization and infection

An observational study was undertaken to describe a nosocomial outbreak cau sed by multiresistant Klebsiella pneumoniae (MRKP), Ten patients in the ped iatric intensive care unit (ICU) at a hospital in Madrid were colonized by or infected with MRKP from October 1997 to April 1998, Thirty-two patients with MRKP-negative surveillance cultures who were admitted to the ICU durin g the outbreak period were selected as control patients. Random amplified p olymorphic DNA analysis of MRKP isolates revealed patterns that were indist inguishable from each other. After identification of colonized patients by surveillance cultures and implementation of standard and contact precaution s, the outbreak was controlled. An age <12 weeks (odds ratio [OR], 13.1) an d previous treatment with third-generation cephalosporins and aminoglycosid es (OR, 31.2) were independently associated with MRKP colonization and/or i nfection. Individual exposure to antibiotics, irrespective of other clinica l determinants, is a risk factor for MRKP acquisition. Screening high-risk patients during outbreaks and reducing the use of third-generation cephalos porins and aminoglycosides contribute to the control of these epidemics.