ANTIBIOTIC-RESISTANCE PATTERN OF HEAT-LABILE ENTEROTOXIN (LT) PRODUCING ESCHERICHIA-COLI ISOLATED FROM CHILDREN WITH DIARRHEA IN BANGLADESH- CLONAL RELATIONSHIPS AMONG ISOLATES WITH DIFFERENT RESISTANT PHENOTYPES

Fifty-six heat-labile enterotoxin-producing (LT+) Escherichia coli iso lated from 33 children less than 5 years of age with diarrhoea were an alysed for resistance to antibiotics, plasmid contents, and clonal rel ationships among isolates by ribosomal RNA (rRNA) fingerprinting (ribo typing). Fifty-five (98.2%) of the LT+ isolates were resistant either to tetracycline alone (48.2%) or to tetracycline and one or more other antibiotic, i.e. ampicillin, streptomycin, chloramphenicol, trimethop rim-sulfamethxazole, or nalidixic acid. Most of the isolates harboured one or more plasmid but antibiotic resistance patterns did not always correlate with particular plasmid patterns. Ribotyping of the isolate s using the restriction endonuclease EcoRI revealed a total of 7 diffe rent ribotypes, and ribotypes were shared by E. coli isolates with dif ferent antibiotic resistant phenotypes. The results indicate that in B angladesh at least 7 different clones of LT+ E. coli acquired resistan ce to one or more different antibiotics in various combinations. Howev er, a similar drug resistance pattern was not mediated by the same set of plasmids in all strains. The mechanism for the emergence and sprea d of antibiotic resistance among E. coli should be investigated furthe r in Bangladesh, where LT+ E. coli is an important agent of early chil dhood diarrhoea.