Prevalence of IncI1-Iγ and IncFIA-FIB type plasmids in extended-spectrum β-lactamase-producing Klebsiella pneumoniae strains isolated from the NICU of a North Indian hospital

Abstract

We studied the molecular mechanism of resistance in extended-spectrum b-lactamase (ESBL)-producing Klebsiella pneumoniae isolated from a neonatal intensive care unit (NICU) of one of the hospitals in North India. A total of 3000 clinical samples were collected from a NICU (January 2009 to February 2011), of which 523 strains were K. pneumoniae positive and 262 of them were ESBL-producing K. pneumoniae strains. All of the ESBL-producing clinical isolates were susceptible to carbapenems. However, the majority of the clinical isolates (30-96 %) were resistant to a wide range of antibiotics including antibiotic/inhibitor combinations. The MIC values confirmed that these isolates were highly resistant to cephalosporins and aztreonam. In the 262 ESBL-producing K. pneumoniae isolates, 15 different enterobacterial repetitive intergenic consensus (ERIC)-PCR-typed phylogenetic groups were identified and reconfirmed by PFGE. Characterization of plasmids from each representative member of these phylogenetic groups revealed the presence of three plasmids of different sizes. Conjugation experiments confirmed the presence of different resistance markers only on the 154 kb plasmid. PCR amplification and sequence analysis revealed that bla CTX-M-3 , bla TEM-1 , bla SHV-1 , bla OXA-1 and armA were the predominant resistance markers. Plasmid-replicon typing showed that IncI1-Ic and IncFIA-FIB types are the most prevalent. This study shows the co-existence of multiple ESBL-encoding genes and their polyclonal dissemination among K. pneumoniae clinical isolates in the NICU of a North Indian hospital.

Comparison of biofilm formation and efflux pumps in ESBL and carbapenemase producing Klebsiella pneumoniae

“…Previous studies have shown that the prevalence rate of ESBL-and carbapenemase-producing K.pneumoniae isolates can be varied from 19% to 60% in different countries [22][23][24][25]. To support this result, in our study, 51% of collected isolates were ESBLproducers while 49% of them were carbapenemaseproducers.…”

Analysis of beta-lactamases, bla NDM-1 phylogeny & plasmid replicons in multidrug-resistant Klebsiella spp. from a tertiary care centre in south India

“…Bonnin et al 10 , speculated that IncFII, plasmid replicons endemic to Indian subcontinent, might play a major role in the dissemination of bla NDM gene. This narrow host range, multireplicon plasmid, was also reported to be a frequent carrier of ESBLs, especially bla CTX-M 14 16 23 31 . Interestingly, the prevalent plasmid in bla NDM-1 -producing isolates in this region was also found to be a variant of IncFII, IncFII K .…”

“…Occurrence of ESBL and MBL producers observed in this study and the observation of co-production of these two enzymes by two isolates was in agreement with the findings of the above-mentioned studies. ESBL producers are reported to be often resistant to multiple antibiotics 16 24 . In our study also 60 per cent of the isolates were found to be resistant to all of the antibiotics tested.…”

“…IncF comprises conjugative, low copy number plasmids capable of multireplicon existence, which facilitate their occurrence in a wide host range. Along with bla NDM , the IncF plasmids frequently carry genes for ESBL of clinical importance such as bla CTX-M15 6 14 16 . In addition, IncF plasmids are also known to carry genes encoding resistance to aminoglycosides, which confer multidrug resistance to the host organism 6 14 15 .…”

Beta-lactomics: A New Term Coined in “OMICS”

“…Beta-lacatmases are enzymes coded by specific gene and produced in bacteria to hydrolyze antibiotics and hence cause drug resistance against antibiotics a major health problem. A total of about hundreds of variants of each groups of beta-lactamases have been identified and documented in form of manuscripts and databases in the public domain [3][4][5]. The structural and function diversity of these enzymes are remarkable as evident from the fact that a single mutation may changed its activity towards antibiotic hydrolysis.…”