Multiple drug-resistant Shigella dysenteriae type 1 in Rajbari district, Bangladesh.

Twenty-one Shigellae isolates were obtained from bloody faecal specimens of diarrhoeal patients at Rajbari District Hospital from January 1994 to June 1995, and serogrouped. Fourteen (67%) isolates belonged to the Shigella dysenteriae serogroup and 7 (33%) to Shigella flexneri serogroup. Shigella dysenteriae strains were further serotyped; all were Shigella dysenteriae 1. Each strain was tested for resistance to 6 common antimicrobial agents. The two strains had different antibiotic susceptibility patterns. The 7 S. flexneri showed 6 different resistant patterns and the 14 S. dysenteriae 1 isolates had 4 resistance patterns. One of the S. dysenteriae 1 isolates was resistant to all 6 antimicrobial agents; 10 to 5, and twice to a different combination of 4 antimicrobials. The 14 (100%) S. dysenteriae 1 strains were resistant to 3 major antimicrobial agents: ampicillin, tetracycline, and chloramphenicol; 13 (93%) were resistant to 5 agents: ampicillin, tetracycline, chloramphenicol, trimethoprim-sulphamethoxazole, and nalidixic acid. Ciprofloxacin was the only drug active against all 7 S. flexneri and 13 of the 14 (93%) S. dysenteriae 1 strains.