Emergence of carbapenem-resistant Enterobacter cloacae carrying IMP-26 metallo-β-lactamase in class 1 integron and TEM-104 extended-spectrum β- Lactamase in conjugative plasmid

A clinical isolate of Enterobacter cloacae exhibiting reduced susceptibility to carbapenem and a positive EDTA-disc synergy test was studied for carbapenemase production. MICs were determined with standard procedures. Isoelectric focusing of cell extracts was used for detection of β-lactamases. PCR assays with primers specific for the blaIMP-26 gene and the conserved segments of class 1 integrons and sequence analyses were carried out to identify the gene and to map the metallo-β-lactamase encoding integron. Transferability of the gene was assessed with conjugation experiments. To identify the location of the blaTEM-104 gene, conjugation experiments and plasmid electrophoresis were carried out and amplified by PCR. A carbapenem-resistant E. cloacae was found to carry IMP-26 metallo-β-lactamase in class 1 integron and TEM-104 extended-spectrum β- lactamase in conjugative plasmid. Existence of multiple resistant genes on plasmids and integrons may pose a serious epidemiological, clinical, and public health threat.   Key words: Metallo-β-lactamases, carbapenemases, Enterobacter cloacae