Resistance to beta-lactams among blood isolates of Salmonella spp. in European hospitals: results from the SENTRY Antimicrobial Surveillance Program 1997-98

The susceptibility to beta -lactams and the beta -lactamase content of 110 Salmonella spp. blood isolates collected during 1997-98 in 19 European centers participating in the SENTRY Surveillance Program were studied. Thirty-one isolates (28%) were resistant to penicillins, due to production of TEM-1 (27 isolates), OXA-1 (three isolates) or TEM-1 + OXA-1 (one isolate). All OXA-1 producers and 10 TEM-1-producing isolates were also resistant to penicillin-clavulanic acid combinations. In the latter isolates, this phenotype was associated with increased production of TEM-1. Sixteen TEM-1-producing Salmonella Enteritidis isolates and one OXA-1-producing S. Typhimurium isolate were able to transfer beta -lactam resistance by conjugation.