Novel Plasmid and Its Variant Harboring both a bla _NDM-1 Gene and Type IV Secretion System in Clinical Isolates of Acinetobacter lwoffii

Abstract

The spread of the bla NDM-1 gene is gaining worldwide attentions. This gene is usually carried by large plasmids and has been discovered in diverse bacteria since it was originally found in Klebsiella pneumoniae. Here we report the complete sequences of a bla NDM-1 -bearing plasmid, pNDM-BJ01, and its variant, pNDM-BJ02, isolated from clinical Acinetobacter lwoffii strains. The plasmid pNDM-BJ01 is 47.3 kb in size and cannot be classified into any known plasmid incompatibility group, thus representing a novel plasmid with an unknown maintenance mechanism. This plasmid contains both a bla NDM-1 gene and a type IV secretion system (T4SS) gene cluster. The T4SS is assigned to the P-type T4SS group, which usually encode a short, rigid pilus, and the bla NDM-1 gene is located within a composite transposon flanked by two insertion elements of ISAba125. Plasmid pNDM-BJ02 is nearly identical to pNDM-BJ01 except that one copy of the ISAba125 element is missing, and it is therefore regarded as a variant of pNDM-BJ01. Sequence alignment indicated that this bla NDM-1 -containing composite transposon, which can also be captured by other mobile elements, was probably a product of multiple recombination events and can move as a whole by transposition.

Using populations of human and microbial genomes for organism detection in metagenomes

“…Cold Spring Harbor Laboratory Press on May 10, 2018 -Published by genome.cshlp.org Downloaded from the important drug resistance factor NDM-1 (Klebsiella pneumonia plasmid pNDM-US, Acinetobacter baumannii plasmid pAbNDM-1, or Escherichia coli plasmid p271A) (Hu et al 2012), and then reads used to identify these plasmids were checked for their gene assignments. In total, 33 of the 131 sequencer runs indicate the presence of a NDM-1 related gene (using a minimum of 10 reads to support the NDM-1 related gene call), and in seven sequencer runs, the genes were linked with the p271A plasmid.…”

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

“…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). Although in Acinetobacter the bla NDM-1 has most frequently been found chromosomally located, some reports have described this gene located on plasmids (7,8).…”

Detection of New Delhi Metallo-β-Lactamase (Encoded by bla NDM-1 ) in Acinetobacter schindleri during Routine Surveillance

“…However, MRSN 10319 was susceptible to all aminoglycosides tested (Table 1). Sequence comparison to pNDM-BJ02 suggests that the original promoter sequence for this gene has been disrupted by an upstream transposition event, as previously noted (10). Hu and colleagues demonstrated that the plasmid had a relatively high transfer frequency (9.1 ϫ 10 Ϫ3 to 1.3 ϫ 10 Ϫ2 per donor cell) to E. coli J53 Azi r , suggesting that this plasmid has a high propensity for horizontal transmission (10).…”