Nosocomial outbreak of CTX-M-15-producing E. coli in Norway
Seven E. coli isolates expressing resistance to 3rd generation cephalosporins were recovered from blood (n=2), kidney and lung tissue (n=1), and urinary tract (n=4) samples from seven patients hospitalised or recently discharged from the Divisions of Geriatrics and Pulmonary Medicine, Central Hospital of Rogaland, between July and September 2004. All isolates expressed a typical ESBL-cefotaximase profile (cefotaxime MIC>ceftazidime MIC) with clavulanic acid synergy. A blaCTX-M-15 genotype was confirmed in six strains that were coresistant to gentamicin, nitrofurantoin, trimethoprim-sulfamethoxazole and ciprofloxacin. A blaCTX-M-3 genotype was detected in the last strain. XbaI-PFGE patterns of the six blaCTX-M-15 isolates revealed a clonal relationship. BlaCTX-M-15 strains were also positive for the ISEcp1-like insertion sequences that have been shown to be involved in the mobilization of blaCTX-M. Further analyses revealed two blaCTX-M-15-positive E. coli urinary isolates clonally related to the outbreak strain from two different patients at the same divisions in January and February 2004. These patients were later re-hospitalised and one had E. coli with an ESBL-cefotaximase profile in sputum and nasopharyngeal specimen during the outbreak period. Clinical evaluation suggests that the CTX-M-producing E. coli strains contributed to death in three patients due to delayed efficient antimicrobial therapy. The outbreak emphasises the epidemic potential of multiple-antibiotic-resistant CTX-M-15-producing E. coli also in a country with low antibiotic usage and low prevalence of antimicrobial resistance.
Document Type: Research Article
Affiliations: 1: Reference Centre for Detection of Antimicrobial Resistance (K-res), Department of Microbiology and Infection Control, University Hospital of Northern Norway and Department of Microbiology and Virology, University of Tromsø, 2: Department of Infection Control, 3: Department of Pulmonary Medicine, Stavanger University Hospital Norway, and 4: Department of Pathology and Microbiology, University of Bristol, UK
Publication date: 2007-02-01