The problem of emerging chloramphenicol resistance in typhoid fever--a preliminary report.

Drug sensitivity of Salmonella typhi isolated from 25 blood culture positive cases of typhoid fever who presented between May and July 1990 was tested to determine their in vitro susceptibility to various antimicrobials. Twenty-one of them (84%) showed resistance to chloramphenicol and 24 (96%) to cotrimoxazole. All the 25 cases were sensitive to norfloxacin, gentamicin and cephalexin. Sixteen of 21 chloramphenicol resistant typhoid cases in whom chloramphenicol was initially started failed to respond to this drug even after 5 to 7 days, thereby indicating that in vivo response matched with the in vitro sensitivity. Clinical response to norfloxacin, whether given initially or following chloramphenicol failure, was prompt and satisfactory. Norfloxacin thus appears to be a good choice in such cases.