MOLECULAR EPIDEMIOLOGY OF AN OUTBREAK DUE TO EXTENDED-SPECTRUM BETA-LACTAMASE-PRODUCING ENTEROBACTERIA IN A FRENCH HOSPITAL

Between June 1992 and June 1993, 128 extended-spectrum beta-lactamase- producing enterobacteria (123 Klebsiella pneumoniae, 3 Escherichia col i, 1 Enterobacter aerogenes, and 1 Citrobacter diversus) were collecte d in a French university hospital. These isolates were recovered mainl y from patients hospitalized in intensive care and neurosurgery units. The 128 strains were divided into 14 antibiotypes (ATBs; ATB1 to ATB1 4); 102 of 103 nonredundant isolates were shown to produce an SHV-4-re lated extended-spectrum beta-lactamase (pI 7.8, hybridization with a b la(SHV) probe); the remaining strain (Kp 2108) produced a TEM-3-relate d extended-spectrum beta-lactamase (pI 6.3, hybridization with a bla(T EM) probe). For representative isolates, five plasmid profiles (PI to PII-4), eight ribotypes (E1 to E8), and seven arbitrarily primed polym erase chain reaction profiles (A1 to A7) were obtained. The results su ggest the spread of an epidemic strain of Klebsiella pneumoniae (E1, A 1, PI, various ATBs) from an intensive care unit throughout the hospit al. Another epidemic strain (E2, A2, PI, ATB4) was confined to the neu rosurgery unit. Other extended-spectrum beta-lactamase-producing Klebs iella pneumoniae of ribotypes distinct from E1 or E2 might result from the spread of an epidemic plasmid, such as reported for isolates of o ther enterobacterial species. Conversely, they might represent importe d cases, such as the strain Kp 2108, which produced a TEM-3-related be ta-lactamase.