[Typhoid bacilli resistant to chloramphenicol and multiresistant to antibiotics isolated at the beginning of 1971]

The sensitivity of chloramphenicol (C) of 286 S. typhi strains, isolated during the last 15 years in Moldavia, was tested. The minimum inhibitory concentration (MIC) of C with regard to most of the strains ranged between 1.5 and 3 mcg/ml. The following stains were identified: strain W isolated from the feces of a carrier in 1971, with a ACKSSuT-Cl2Hg resistance spectrum transferable to E. coli K12(MIC of C less than or equal to 200 mcg/ml), 2 strains (phage type A and C1, isolated from patients, one from the feces in 1972 and the other haemoculture in 1973) with a non-transferable CSu resistance spectrum (MIC of C less than or equal to 6 and less than or equal 12 mcg/ml respectively), and 18 strains (13 phage type D9, 3 phage type Ci and 2 phage type A), isolated from 3 epidemic foci, which proved to contain variants selectable in vitro by C (MIC up to 50 mcg/ml). The resistance spectrum of the variants was not CSU transferable. Conclusions are drawn concerning the necessity of a restricted utilization of chloramphenicol.