Genotype identifications of ESBLs and AmpC β-Iactamase of a Enterococcus gallinarum isolated from chloebia gouidiae / 中国兽医学报

ABSTRACT

The genotypes of extended spectrum β-laetamases(ESBLs) and AmpC β-lactamases produced by Enterococcus gallinarum isolated from chloebia gouldiae were determined to elucidate the evolution mechanism of the resistant genes.The minimum inhibitory concentrations (MICs) of 18 antibacterial drugs against the Enterococcus gallinarum were detected with two dilution method,and the ESBLs and AmpC β-lactamases from the bacterium were amplified by PCR using the primers of TEM,SHV,CTX-M,ACC,CIT,DHA,EBC,FOX and MOX,respectively.The PCR products were cloned and then the cloned fragments were sequenced to identify their genotypes and subtypes.The bacterium was proved to be a ESBL-producing and AmpC β-lactamase-producing bacterium,showing severe resistant to the other drugs,except the third and forth cephalosporins,carbopenems and fosfomycin.Compared with that of AJ847364 (TEM-116),the sequence of the TEM-type was characterized by two nucleotide mutations (512T→A and 695A→C),which led to two mutations of amino acids(17111e→Lys and 232Lys→Thr),showing that the detected TEM-type was a new genotype,the sequence of the AmpC β-lactamase was similar to that of EF078894 (ACT-like type)with a 97% homology.The genotype of ESBLs of Enterococcus gallinarum was a new TEM-type derived from the TEM-type ESBLs of klebstella pneumoniae isolated from the same avian.The genotype of AmpC lactamase was ACT-type,which probably concerned with β-1actam antibiotics used.