Molecular epidemiology of an outbreak due to IRT-2 beta-lactamase-producing strains of Klebsiella pneumoniae in a geriatric department

In February 1998, 195 patients in the geriatric department of a French hosp ital were screened for the presence of co-amoxiclav-resistant Klebsiella pn eumoniae, Eleven co-amoxiclav-resistant isolates obtained all produced an i dentical IRT-2 beta-lactamase. These K. pneumoniae isolates were clonally r elated and harboured a c. 55 kb non-conjugative plasmid encoding a non-clas s-1 integron-located bla(IRT-2) gene. This study underlines that geriatric departments may be a reservoir for antibiotic-resistant strains and that IR T beta-lactamase-producing strains may be nosocomial pathogens.