Prevalence and antimicrobial susceptibility of Salmonella serotypes in patients from Ribeirão Preto, São Paulo, Brazil, between 1985 and 1999.

Salmonella strains isolated from 1,138 samples representing 28,199 biological materials (stool, urine, blood and other fluids), collected between January 1985 and January 1999 at a reference University Hospital in Ribeirão Preto, São Paulo, Brazil, were studied. The most frequently detected serotypes were Salmonella enterica subspecies enterica serotype 4,5,12:i:- (S. I 4,5,12:i:) (21.2%), S. agona (15.8%) and S. enteritidis (11.3%). A changing pattern of Salmonella serotypes was observed between 1985-1999. S. agona, which represented 27% of Salmonella serotypes isolated from 1985-1989, declined to 4% during the period from 1995 to 1999. S. enteritidis isolation remained below 1% until 1989; rose to 5.9% between 1990 and 1994, and increased to 32.3% between 1995-1999. S. I 4,5,12:i:-; S. enteritidis; S. typhimurium; S. dublin and S. infantis, showed low to moderate resistance profiles to most antimicrobial drugs. Nalidixic acid and tetracycline were the most and the least effective drugs, respectively, in the disk diffusion tests. We encountered changes in salmonellosis epidemiology in this geographical region.