HIGH-FREQUENCY OF STRAINS MULTIPLY RESISTANT TO AMPICILLIN, TRIMETHOPRIM-SULFAMETHOXAZOLE, STREPTOMYCIN, CHLORAMPHENICOL, AND TETRACYCLINE ISOLATED FROM PATIENTS WITH SHIGELLOSIS IN NORTHEASTERN BRAZIL DURING THE PERIOD 1988 TO 1993

The occurrence and antimicrobial resistance pattern of Shigella isolat es obtained from persons in community and hospital-based studies of di arrhea and matched controls in northeastern Brazil were studied. The i solation rate of Shigella spp. from patients with diarrhea during 1988 to 1993 varied from 4.5% (26 of 575) for the urban community of Gonca lves Dias to 6.7% (12 of 179) and 5.9% (7 of 119) for Hospital Infanti l and Hospital Universitario, respectively. Of the 55 Shigella isolate s (45 from patients with diarrhea, 8 from controls, and 2 undetermined ) 73% (40 of 55) were Shigella flexneri, 16% (9 of 55) were S. sonnei, 7% (4 of 55%) were S. boydii, and 4% (2 of 55) were S. dysenteriae. O f 39 S. flexneri strains, over half were resistant to ampicillin, trim ethoprim-sulfamethoxazole, or both. Over 64% were resistant to strepto mycin, chloramphenicol, and tetracycline. Overall, 82% of all S. flexn eri isolates were resistant to four or more antimicrobial agents teste d. As elsewhere, in the northeast of Brazil, ampicillin and trimethopr im-sulfamethoxazole are no longer reliable for treatment of S. flexner i infection. Most Shigella strains were resistant to four or more anti microbial agents. Nalidixic acid was still useful for treatment of inf ections due to S. flexneri.