[Antimicrobial resistance in strains of Salmonella enterica isolated in the Hospital de Basurto (Bilbao) from 1987 to 1990]. / Resistencia antimicrobiana en cepas de Salmonella enterica aisladas en el Hospital de Basurto (Bilbao) desde 1987 hasta 1990.

BACKGROUND: Rate development of antimicrobial resistance of Salmonella strains in Hospital Basurto of Bilbao from 1987 to 1990 and to study their resistance mechanism. METHODS: The antimicrobial resistance for all strains isolated (1201 strains) was performed by means of a agar-diffusion test. We selected 32 multi-resistant strains for additional study (MIC, conjugation, IEF, and plasmid profile). RESULTS: The most frequent isolated serotypes were S. enteritidis (79.01%), S. typhimurium (8.5%) and Salmonella serogroup C1 (6.9%). The resistance to one or more of 17 antimicrobial rose significantly: 9.6% in 1987; 10.25% in 1988; 16.45% in 1989 and 13.73% in 1990. The percentage of resistant serotypes were: S. typhimurium (40.2%); Salmonella serogroup B (31.8%); Salmonella serogroup C1 (16.8%); Salmonella serogroup D1 (13.04%); Salmonella serogroup C2 (9.09%) and S. enteritidis (8.4%). In 27 multi-resistant strains and their transconjugants, beta-lactamase bands with a pl: 5.4 and/or 5.6 compatible with TEM-1 and/or TEM-2 were observed. Also, these strains carried a plasmid of high molecular weight (125 MD). CONCLUSIONS: Although, the resistance of Salmonella is not a serious problem in our environment this situation is raising progressively with a greater number of strains with plasmid mediated beta-lactamases. So, the antimicrobial policy will be more severe and righ in both hospital and extrahospital surrounding.