Detection of NDM-1-, CTX-M-15-, and qnrB4 -Producing Enterobacter hormaechei Isolates in Brazil

Abstract

A fter the first description of NDM-1 carbapenemase in a Providencia rettgeri isolate in Brazil in February 2013 (1), the public hospital where this isolate was recovered began an active surveillance in search of asymptomatic carriers and in the hospital environment. Furthermore, a retrospective study of carbapenem-resistant isolates stored at that hospital since 2012 was performed. Six NDM-1-producing Enterobacter hormaechei subsp. oharae isolates, identified by the Vitek2 system and hsp60 genotyping, were recovered and characterized by phenotypic assays and molecular techniques, such as PCR and DNA sequencing (2, 3). One isolate (CCBH10892) was recovered from a rectal swab of a patient at the intensive care unit (ICU) in September 2012 (a time period prior to the isolation of NDM-positive P. rettgeri). The others were isolated from March to May 2013 from rectal swabs of patients (n ϭ 4) and a sink (n ϭ 1) located in the same ICU.Pulsed-field gel electrophoresis (PFGE) of XbaI-digested DNA (4) showed that all isolates belonged to the same clone; the isolates were considered to be multidrug resistant, as they were susceptible only to amikacin (MIC range of 8 to 16 mg/liter) and polymyxin B (MIC Յ 1 mg/liter) by the Etest method (Fig. 1). Besides bla NDM-1 , all these isolates carried bla CTX-M-15 , qnrB4, and aac(6)-Ib genes, detected by PCR and sequencing. Plasmid analysis by restriction digests with S1 nuclease and Southern blotting (5) showed that the bla NDM-1 and qnrB4 genes were located on the same plasmids, ranging in size from 420 to 490 kb (Fig. 1).To obtain a comprehensive in-depth view of the genetic structure surrounding the bla NDM-1 , bla CTX-M-15 , and qnrB4 genes, the genomic sequence of the CCBH10892 isolate was determined on an Illumina MiSeq system. A total of 1,149,470 reads (5,373,710 bp) were assembled with Geneious assembler (Biomatters) to generate 56 contigs. We found bla NDM-1 in a 94,795-bp contig flanked by a truncated ISAba125 sequence at the right boundary and by a bleomycin resistance gene (ble MBL ) at the left (GenBank accession number KF727591). This region shared 99% identity with the NDM region present in a plasmid carried by a Klebsiella pneumoniae isolate from Taiwan (6). In this contig, some conjugation and plasmid transfer genes and a replication protein gene belonging to the IncF group were also observed. However, this replicon could not be detected by the PCR-based replicon typing (PBRT) scheme (7).The qnrB4 gene was found in a 16,569-bp contig in which ISCR1 and genes encoding permeases (sapA, sapB, and sapC) and phage shock proteins (pspA, pspB, pspC, and pspD) and AmpC bla DHA-1 (GenBank accession number KF646592) were also observed. This same region has been reported in different plasmids of other bacterial species (8).bla was integrated into the chromosome associated with an upstream ISEcp1 element in a 277,989-bp contig (part of it is in the sequence available at GenBank accession number KF727590). This transposition unit was inserted into the flhC gene, which enc...

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

“…steigerwaltii" in 2013; it is highly similar to the partial sequence of a plasmid isolated from "E. hormaechei subsp. oharae" in 2012 (23) in Porto Alegre, 1,571 km away from Rio de Janeiro.…”

“…Subsequently, plasmid-borne bla NDM-1 genes were identified in Enterobacter hormaechei (23), Enterobacter cloacae, P. rettgeri, K. pneumoniae (24), and Acinetobacter baumannii (25), but the sequences of these plasmids remain unknown. In E. hormaechei, the plasmid was reported be ϳ420 to 490 kb (23), while in E. cloacae, P. rettgeri, and K. pneumoniae, the plasmid was reported to be ϳ230 kb (24) and in A. baumannii the estimated plasmid size was 100 kb (25).…”

Perfil de resistencia a antibióticos en bacterias que presentan la enzima NDM-1 y sus mecanismos asociados: una revisión sistemática

“…Esto podría deberse a que este país fue uno de los primeros junto con Estados Unidos en los cuales fueron encontrados los primeros hallazgos de esta enzima en el continente en el año 2010 (28)(29). Aunque cabe destacar que en América, Brasil está aportando considerablemente en el número de casos, después del primer aislamiento de Providencia rettgeri con presencia de la enzima en febrero de 2013 (30), así como el reporte de la enzima en otros géneros bacterianos como Morganella, Enterobacter y Acinetobacter (30)(31)(32)(33).…”

New Delhi metallo-beta-lactamase-1-producing Acinetobacter spp. infection: report of a survivor

“…Fragments of the soft tissue from his toe were sent for culture and yielded growth of a carbapenem-resistant Providencia rettgeri, in which bla NDM-1 was detected (5) . A second case was detected in the same hospital in a retrospective analysis of samples from hospitalized patients (10) . In Londrina, Paraná, the fi rst case of NDM-1-producing Acinetobacter baumannii in Brazil was reported; a 71-year-old man was admitted to the intensive care unit with respiratory failure and died on hospitalization day 60 (11) .…”