Outbreak of a Multiresistant Klebsiella pneumoniae Strain in an Intensive Care Unit: Antibiotic Use as Risk Factor for Colonization and Infection

Angel Asensio, Antonio Oliver, Paulino González-Diego, Fernando Baquero, Jose Claudio Pérez-Díaz, Purificación Ros, Javier Cobo, Margarita Palacios, Dolores Lasheras, Rafael Cantón
2000 Clinical Infectious Diseases  
An observational study was undertaken to describe a nosocomial outbreak caused by multiresistant Klebsiella pneumoniae (MRKP). Ten patients in the pediatric 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 during the outbreak period were selected as control patients. Random amplified polymorphic DNA analysis of MRKP isolates revealed
more » ... patterns that were indistinguishable from each other. After identification of colonized patients by surveillance cultures and implementation of standard and contact precautions, the outbreak was controlled. An age !12 weeks (odds ratio [OR], 13.1) and previous treatment with third-generation cephalosporins and aminoglycosides (OR, 31.2) were independently associated with MRKP colonization and/or infection. Individual exposure to antibiotics, irrespective of other clinical determinants, is a risk factor for MRKP acquisition. Screening high-risk patients during outbreaks and reducing the use of third-generation cephalosporins and aminoglycosides contribute to the control of these epidemics. Klebsiella pneumoniae has been associated with 2%-5% of nosocomial infections, particularly those involving the lower respiratory and urinary tracts [1, 2]. Resistance of this species to third-generation cephalosporins was first described in the early 1980s, and a linear increase in resistance has occurred since 1986 [3, 4] . Resistant isolates most likely gain their resistance by producing extended-spectrum b-lactamases (ESBLs). These enzymes are derivatives of common b-lactamases that have undergone one or more amino acid substitutions near the active site of the enzyme, thus increasing the affinity and the hydrolytic ability of the enzyme for third-generation cephalosporins and monobactams [5] . Genes encoding these enzymes are generally located in transferable plasmids, which often code resistance determinants to other antimicrobial agents such as aminoglycosides [6] . The epidemiology of ESBL has previously been studied, and several works have described the potential risk factors associated with multiresistant K. pneumoniae (MRKP) isolates [7] [8] [9] [10] . Nevertheless, studies addressing independent risk factors associated with K. pneumoniae colonization or infection are scant in the literature. The present study describes a no-
doi:10.1086/313590 pmid:10619733 fatcat:x3vrvce26nepnarcf5lvpravl4