Emergence of NDM-producing non-baumannii Acinetobacter spp. isolated from China

Abstract

One hundred and thirty-six bla OXA-51-negative strains were identified from 1,067 Acinetobacter calcoaceticus-A. baumannii complex (ACB complex) isolates, which were collected during October 2010 to March 2013 from 15 general hospitals in 10 cities throughout Zhejiang Province, China. Seven of the 136 bla OXA-51-negative ACB complex isolates were New Delhi metallo-β-lactamase-1 (NDM-1)-positive, among which three were identified as A. nosocomialis and four were identified as A. pittii strains using 16S-23S rRNA gene intergenic spacer (ITS) sequencing and partial RNA polymerase β-subunit (rpoB) sequencing. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analysis showed that the seven NDM-positive isolates belonged to three clonal strains with three novel sequence types (STs). Polymerase chain reaction (PCR) assays and DNA sequence analysis of the carbapenemase and other β-lactamase genes indicated that all the isolates harbored the bla NDM-1 gene, and that only one strain of A. nosocomialis isolates harbored both bla NDM-1 and bla OXA-23. All of them were positive for bla ADC, from which three novel bla ADC genes (designated as bla ADC-69, bla ADC-70, and bla ADC-71) were detected for the first time. The presence of ISAba125 upstream of bla NDM-1 was identified through genetic environment analysis. Carbapenem resistance can be transferred from A. nosocomialis and A. pittii to Escherichia coli EC600 by the conjugation experiment. Plasmid analysis, DNA hybridization, and extraction experiments indicated that bla NDM-1 was located on a plasmid of approximately 50 kb. In conclusion, we characterized the dissemination of NDM-1-positive A. pittii strains in Zhejiang Province, China, and reported the NDM-producing A. nosocomialis for the first time.

Characterization of Tn 3000 , a Transposon Responsible for bla NDM-1 Dissemination among Enterobacteriaceae in Brazil, Nepal, Morocco, and India

“…These enzymes have now been detected worldwide in Enterobacteriaceae (3), in Pseudomonas aeruginosa (4), and in many different Acinetobacter species (5). It has been proposed that the dissemination of the bla NDM-1 gene among Acinetobacter strains is mediated by a composite transposon designated Tn125, with two ISAba125 copies bracketing the resistance gene module (6).…”

Emergence of KPC-2-Producing Pseudomonas aeruginosa Sequence Type 463 Isolates in Hangzhou, China

“…All 389 imipenem-resistant isolates detected by the KirbyBauer disk diffusion method, as recommended by Clinical and Laboratory Standards Institute (CLSI) guidelines (5), were screened for the most common carbapenemase genes, including bla KPC (6), bla NDM-1 (7), bla VIM , and bla IMP (8). For the bla KPCpositive isolates, analyses of the other ␤-lactamase genes, including bla , bla CTX-M , bla TEM , bla SHV , bla PER , and bla VEB , were performed.…”

Emergence of genetically unrelated NDM-1-producing Acinetobacter pittii strains in Paraguay

“…pittii has recently been recognized as a key organism for the dissemination of NDM, since it has been associated with the dispersal of this carbapenemase in such diverse scenarios as food of animal origin and sewage, and has been responsible for both sporadic human infection and large outbreaks in hospital units. 10,13,14 Until now, non-baumannii Acinetobacter spp. expressing NDM have not been described in the American continent.…”