Screening of NDM-1 gene in gram-negative bacilli with decreased sensitivity to carbapenems / 国际检验医学杂志

ABSTRACT

Objective To determine new delhi metallo-β-lactamase-1 (NDM-1 )gene in strains of gram-negative bacilli with de-creased sensitivity to carbapenems,and to investigate the epidemic situation of strains carrying NDM-1 gene in Guangzhou area. Methods 105 strains of gram-negative bacilli with decreased sensitivity to carbapenems isolated from 201 1 to 2014 were collected. The conserved sequences of NDM-1 gene were screened initially by using polymerase chain reaction(PCR)amplification,and posi-tive strains were confirmed by PCR amplification of the whole sequence.Then NDM-1 gene was cloned into plasmid pUCm-T and sequenced.Results The resistance rates of Enterobacteriaceae bacteria against meropenem,ertapenem and imipenem were 29.09%, 50.91% and 29.09%,respectively.All strains of Acinetobacter baumanii were resistant to meropenem and imipenem.The resist-ance rates of Pseudomonas aeruginosa against meropenem and imipenem both were 88.46%.4 strains were NDM-1 gene positive, including 1 strain of Klebsiella pneumoniae,2 strains of Escherichia coli,1 strain of Enterobacter cloacae.Successful establishment of cloning plasmid pUCm-T-NDM-1 was confirmed by using double enzyme digestion and sequencing.The sequencing results were compared with BLAST,it was showed that the sequences were exactly the same in four cloned plasmids,and sequences of NDM-1 were also exactly the same with those in domestic and foreign.Conclusion Strains of NDM-1 producing gram-negative bacilli exist in Guangzhou area,and whole sequence of NDM-1 gene carried in these strains are exactly the same with those found in foreign.