Eighty S. typhi strains isolated during the period of one year (July 1
989 to June 1990) were tested for susceptibility to chloramphenicol, a
mpicillin, cotrimoxazole, gentamicin, kanamycin, cefazolin, furazolido
ne and ciprofloxacin. Determination of minimum inhibitory concentratio
n (MIC) by tube dilution method showed that the multiply resistant S.
typhi strains were resistant to chloramphenicol and ampicillin up to a
concentration of 1000-mu-g/ml. MIC of sulphamethoxazole was found to
be 800-mu-g/ml and trimethoprim 160-mu-g/ml. The presence of R plasmid
was demonstrated by resistance transfer experiments using Esch. coli
K12 (F-Lac + Nal-) as the recipient. On phage typing, most of the mult
iresistant S. typhi isolates were found to belong to phage type E1.