First Identification of bla NDM-1 Producing Escherichia coli ST 9499 Isolated from Musca domestica in the Urban Center of Rio de Janeiro, Brazil.

The present study presents phenotypic and molecular characterization of a multidrug-resistant strain of Escherichia coli (Lemef26), belonging to sequence type ST9499 carrying a blaNDM-1 carbapenem resistance gene. The bacterium was isolated from a specimen of Musca domestica, collected in proximity to a hospital in Rio de Janeiro City, Brazil. The strain was identified as E. coli by matrix-assisted laser desorption-ionization time of flight mass spectrometry (Maldi-TOF-MS) and via genotypic analysis (Whole-Genome Sequencing-WGS), followed by phylogenetic analysis, antibiotic resistance profiling (using phenotypic and genotypic methods) and virulence genotyping. Interestingly, the blaNDM-1 was the only resistance determinant detected using a panel of common resistance genes, as evaluated by PCR. In contrast, WGS detected genes conferring resistance to aminoglycosides, fluoroquinolones, quinolones, trimethoprim, beta-lactams, chloramphenicol, macrolides, sulfonamide, tetracycline, lincosamide and streptogramin B. Conjugation experiments demonstrated the transfer of carbapenem resistance, via acquisition of the blaNDM-1 sequence, to a sensitive receptor strain of E. coli, indicating that blaNDM-1 is located on a conjugative plasmid (most likely of the IncA/C incompatibility group, in association with the transposon Tn3000). Phylogenetic analyses placed Lemef26 within a clade of strains exhibiting allelic and environment diversity, with the greatest level of relatedness recorded with a strain isolated from a human source suggesting a possible anthropogenic origin. Analysis of the virulome revealed the presence of fimbrial and pilus genes, including a CFA/I fimbriae (cfaABCDE), common pilus (ecpABCDER), laminin-bind fimbrae (elfADG), hemorrhagic pilus (hcpABC) and fimbrial adherence determinants (stjC) indicates the ability of strain Lemef26 to colonize animal hosts. To the best of our knowledge, this study represents the first report of blaNDM-1 carbapenemase gene in an E. coli strain isolated from M. domestica. In concordance with the findings of previous studies on the carriage of MDR bacteria by flies, the data presented herein provide support to the idea that flies may represent a convenient means (as sentinel animals) for the monitoring of environmental contamination with multidrug-resistant bacteria.

Multidrug-resistant Klebsiella quasipneumoniae subsp. similipneumoniae carrying blaNDM-blaCTX-M15 isolated from flies in Rio de Janeiro, Brazil.

OBJECTIVES: Flies have been implicated in the dispersal of medically important bacteria including members of the genus Klebsiella between different environmental compartments. The aim of this study was to retrieve and characterize antibiotic-resistant bacteria from flies collected near to hospitals. METHODS: Flies were collected in the vicinity of medical facilities and examined for bacteria demonstrating phenotypic resistance to ceftriaxone, followed by determination of phenotypic and genotypic resistance profiles. In addition, whole genome sequencing followed by phylogenetic analysis and resistance genotyping were performed with the multidrug-resistant (MDR) strain Lemef23, identified as Klebsiella quasipneumoniae subsp. similipneumoniae. RESULTS: The strain Lemef23, classified by multiple locus sequence typing as novel ST 3397, harboured numerous resistance genes. The blaNDM was located on a Tn3000 element, a common genetic platform for the carriage of this gene in Brazil. Inference of phylogenetic orthology of strain Lemef23 and other clinical isolates suggested an anthropogenic origin. CONCLUSIONS: The findings of this study support the role of flies as vectors of MDR bacteria of clinical importance and provide the first record of blaNDM-1 and blaCTXM-15 in a Brazilian isolate of K. quasipneumoniae subsp. similipneumoniae, demonstrating the value of surveying insects as reservoirs of antibiotic resistance.