Diversity of TEM-52 extended-spectrum β-lactamase-producing non-typhoidal Salmonella isolates in Korea

Results: The isolates were one each of serovars Saintpaul, Stanley and Agona, and two Enteritidis. Cell sonicates of the isolates hydrolysed cefotaxime more efficiently than ceftazidime, and had β-lactamase bands of approximate isoelectric points 6.0 and 7.4. Sequencing revealed that the β-lactamases were TEM-52 and an OXA type. The bla OXA gene was located on a class 1 integron. Cefotaxime resistance, associ- ated with TEM-52, was transferred by conjugation. Identical pulsed-field gel electrophoresis patterns of XbaI-digested genomic DNA were observed in initially β-lactam-susceptible serovar Agona isolates and subsequent ESBL-producing isolates from an infant, and in two isolates of serovar Enteritidis from two different patients. Conclusions: This study suggests that TEM-52-producing NTS is spreading both clonally and horizontally in Korea.