Abstract
Thirteen Salmonella enterica serotype Typhimurium and one Salmonella enterica serotype Heidelberg strain resistant to expanded-spectrum cephalosporins were isolated from October 2000 to February 2001 from infants with gastroenteritis in Iasi, Romania. In all but one serotype Typhimurium isolate, resistance was due to the production of a CMY-2 cephalosporinase encoded by a nonconjugative plasmid. The remaining isolate produced an SHV-5-type beta-lactamase. Typing by pulsed-field gel electrophoresis indicated that the CMY-2-producing serotype Typhimurium isolates were related.