Chloramphenicol resistance in Salmonella typhi. Report from Bombay

Chloramphenicol resistance to Salmonella typhi in 1989 was 16% in Hinduja Hospital. From Jan to June 1990, this resistance has increased to 81%. 74 strains of blood culture isolated of S typhi obtained from Jan to June were subjected to antibiotic sensitivity testing by disc diffusion technique of Kirby and Bauer 60 strains were found to show a block resistance tochloramphenicol, Ampicillin, Co-trimoxazole, Streptomycin, Tetracycline and Carbenicillin. All strains were sensitive to quinolones. Resistance was record and MIC done in 50 resistant strains by modified National Committee for Clinical Laboratory Standards [NCCLS] according to recommended break points and resistance to Chloramphenicol was confirmed. Of the 47 strains isolated, 34 had received treatment with either chlorampheniicol, Ampicillin or Cotrimoxazole in adequate dosages. In 39 of these 47 patients, Salmonella typhi was isolated after 14 days duration of fever. Plasmid analysis revealed presence of 100 megadalton plasmid in majority of cases. Most patients responded to fluoroquinolones but amongst the admitted patients complications such as Myoglobinuria in 2 cases, perforation in 4 cases, acute Renal failure in 2 cases and typhoid spine in 1 case were seen. Phage typing results of 19 strains were E-8, 0-6.