Comparison of phenotypic tests for detecting BKC-1–producing Enterobacteriaceae isolates

Abstract

Carbapenemase-producing Enterobacteriaceae may exhibit in vitro susceptibility to carbapenems, especially those producing weak carbapenemases. Routine clinical laboratories have employed phenotypic tests for screening such isolates. BKC-1 is a recently reported carbapenemase that shows weak carbapenemase activity. In this study, we aimed to evaluate the behavior of distinct phenotypic methods against BKC-1-producing Enterobacteriaceae.

Antimicrobial resistance in Enterobacteriaceae in Brazil: focus on β-lactams and polymyxins

“…Polymyxin resistance in E. cloacae and K. pneumoniae strains was also reported from Porto Alegre, south of Brazil 61, 96. To date, interruption of mgrB gene by insertion sequences or missense mutations is the most frequent mechanism of polymyxin resistance in K. pneumoniae in Brazil 93, 97. The most recent evidence of the amazing polymyxin resistance problem in Brazil came from a report from São Paulo, the largest city in Latin America.…”

“…To date it has only been found in K. pneumoniae in a low frequency, possible due to the fact that the bla BKC-1 gene is located in a small transferable, non-conjugative plasmid 92, 93…”

Frequency of BKC-1-Producing Klebsiella Species Isolates

“…More studies with greater numbers of isolates from all Brazilian states are necessary to assess the real prevalence of isolates carrying bla BKC-1 . It is important to note that such new studies must search for bla BKC-1 using molecular techniques, since phenotypic tests may not accurately detect BKC-1-producing isolates (8). In conclusion, prudent use of antimicrobials and strict adherence to infection control measures seem to be the only effective tools for preventing the acquisition and spread of new carbapenemase-encoding genes.…”

Mobilization of bla BKC-1 by IS Kpn23 ?

“…Identification of additional sequences containing aph(3=)-VIi with context information may reveal more about the mobilization of this gene. bla BKC-1 has been reported in only six K. pneumoniae isolates from São Paulo, Brazil, to date (1,14), and it will be interesting to see how successful this gene becomes, in comparison with bla genes associated with ISEcp1. …”