[Status of emerging drug resistance in Shiga toxin-producing Escherichia coli in Japan during 1996: a minireview].

A total of 192 Shiga toxin-producing Escherichia coli (STEC) strains isolated from the 1996 episodes in Japan were tested for their in vitro susceptibilities to 41 antimicrobial agents. Drug resistance was found with kanamycin, tetracycline, nalidixic acid, ampicillin, streptomycin, sulfamethoxazole, and fosfomycin. The expression of fosfomycin resistance was greatly dependent on culture conditions and resistance was detected (e.g.) when Mueller-Hinton agar or nutrient agar supplemented with horse blood (or glucose-6-phosphate) was used as test media. All the STEC strains belonging to serotype O26 exhibited fosfomycin resistance. Multiple drug-resistant strains spread 8 of 18 prefectures examined. Out of eleven O157: H7 outbreaks, only one outbreak revealed infections due to multiple drug-resistant strains which carried an R plasmid. Tetracycline, streptomycin, and sulfamethoxazole resistance, which was previously described with O157: H7 strains isolated from a large outbreak as well as sporadic cases in the United States, were also found in Japan with human and bovine isolates (but not with porcine isolates). In contrast, the STEC strains were highly susceptible to newer quinolones, cephems, trimethoprim, gentamicin, and azithromycin. No drug resistance was observed with dibekacin and minocycline.