Role of the plasmid-encoded tet(O) gene in tetracycline-resistant clinical isolates of Campylobacter jejuni and Campylobacter coli

Abstract

The prevalence of tetracycline resistance, tetracycline MICs andtet(O) gene localization were investigated in 83Campylobacterisolates from patients suffering from acute gastroenteritis in Germany. Combined biochemical and molecular markers identified 74 isolates (89 %) asCampylobacterjejuni, including seven atypical isolates that failed to hydrolyse hippurate, and nine isolates (11 %) asCampylobactercoli. Tetracycline resistance was detected in six out of nineCampylobacter coliisolates (67 %) and 13 out of 74C. jejuniisolates (18 %). Low-level tetracycline resistance was observed forC. coli(MIC 16 μg ml−1for all strains), whereasC. jejunishowed high-level resistance (MIC >256 μg ml−1for all strains). Both low- and high-level tetracycline resistance was associated with the presence of thetet(O) gene. InC. jejuni,tet(O) was plasmid-encoded in 54 % of tetracycline-resistant isolates, whereas inC. coli,tet(O) appeared to be located on the chromosome.