Objective To detect and identify multidrug resistance gene of new delhi metallo-beta-lactamase (NDM) 1 in a Acinetobacter lwoffii isolate. Methods Tigecycline MICs were used to screen the multidrug isolate while PCR were used to detect the expression of metallo-β-lactamases among the isolates. Species identification and phenotype analysis were carried out by PCR sequencing, Imipenem and EDTA double disc synergy test, respectively. Genetic location of NDM-1 was determined by Conjugation experiments and whole genome sequencing. Results One strain of A. lwoffii with positive expression of NDM-1 was isolated from 458 carbapenem-non-susceptible cases, which without VIM and IMP genes positive expression concomitantly. This strain with expression of NDM-1 gene resist to all β-lactam antibiotics while retaining the susceptibility to amikacin, colistin and tigecycline. Sequencing showed 100% identities with previously reported genes, and whole genome sequencing conformed NDM-1 gene located on a 48. 9 kb plasmid. Conclusions NDM-1, as a na ve mechanism, involved in resistance to carbopenems. The clinical physicians should pay more attention on impact of multidrug resistance of Acinetobacter lwoffii due to the expression of NDM-1.
Key words
new delhi metallo-β-lactamase /
acinetobacter lwoffii /
multidrug resistance gene
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(2012-12-11
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