Resumo

The emergence of New Delhi Metallo-β-lactamase (NDM) constitutes a critical and growing medical issue mainly due the limitation of therapeutical options. Although its spread has begun on the Indian Subcontinent, NDM-producing bacteria has now been reported worldwide, being first reported in Brazil in 2013. Here we described the emergence of five NDM-producing isolates of Enterobacter hormaechei from Rio de Janeiro, Brazil. Bacterial identification was performed by conventional techniques and hsp60 genotyping. Antibiotic susceptibility was determined by disc diffusion method and Etest. Phenotypic carbapenemase production was screened by double-disk diffusion test (DDT) with EDTA and the presence of carbapenemase genes (bla_KPC, bla_NDM) and ESBL genes (bla_TEM, bla_SHV, bla_CTX-M) was investigated by PCR and sequencing. PFGE (XbaI) was carried out to analyze the genetic relationship. Five isolates were recovered between October 2013 and April 2014 from rectal swabs obtained during surveillance (4 isolates) and urine (1 isolate) from non-consecutive patients in four hospitals from Rio de Janeiro metropolitan area. Phenotypically, all strains were positive for Metallo-β-lactamase production and harbored bla_NDM-1, bla_CTX-M-15 and bla_TEM-1. Interestingly one of isolates showed co-production of bla_KPC-2 and bla_NDM-1. The antimicrobial profile showed resistance to all β-lactams, gentamicin and ciprofloxacin; sulfamethoxazole/trimethoprim (80%) and amikacin (20%). Nevertheless all isolates remained susceptible to fosfomycin/trometamol and polymyxin B. Based on PFGE analysis, the isolates were classified into 4 pulsotypes (named A–D). Isolates belonging to pulsotype B (CCBH14395 and CCBH14397) were recovered from the same hospital. Interestingly the isolate of pulsotype A (CCBH14227) was genetically indistinguishable from an NDM-producing E. hormaechei isolate obtained from Rio Grande do Sul reported in 2013 by our group. The presence of bla_NDM-1 gene in genetically distinct isolates of E. hormaechei may indicate that rapid spread of this gene in Brazil, highlighting the capacity of acquisition of different resistance genes by this genus, including the co-production of the two most important carbapenemase. We also emphasize the possibility that some patients are serving as a reservoir for NDM-producing bacteria, because most of isolates of this work were recovered from gut colonization.