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

Abstract

OBJECTIVES: Extended-spectrum beta-lactamase (ESBL)-producing non-typhoidal Salmonella (NTS) isolates in Korea were characterized. PATIENTS AND METHODS: Five isolates of ESBL-producing NTS were isolated from stool specimens of three infants and two adults with diarrhoea. Two infants acquired the infection in the community, and three other infections were hospital acquired. 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 beta-lactamase bands of approximate isoelectric points 6.0 and 7.4. Sequencing revealed that the beta-lactamases were TEM-52 and an OXA type. The blaOXA gene was located on a class 1 integron. Cefotaxime resistance, associated with TEM-52, was transferred by conjugation. Identical pulsed-field gel electrophoresis patterns of XbaI-digested genomic DNA were observed in initially beta-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.