Evaluation of biofilm formation and carbapenem resistance in Klebsiella pneumoniae isolated from clinical samples at a rural hospital in western Uttar Pradesh

Abstract

Introduction: Klebsiella pneumoniae commonly causes healthcare-associated infections and shows multidrug resistance. K. pneumoniae can produce biofilm. Carbapenem resistance in K. pneumoniae is due to the production of carbapenemases mainly. This study was done to evaluate the formation of biofilm and carbapenemase resistance in K. pneumoniae isolates.

Material and methods: A total of 110 K. pneumoniae isolated from various clinical samples were taken, the antibiotic susceptibility test was done by the Kirby disk diffusion method, and biofilm detection was done by the tissue culture plate method. All the carbapenem-resistant isolates were confirmed by multiplex real-time PCR (mPCR). Those found positive for any of the carbapenemase genes were tested by the modified Hodge test (MHT), modified carbapenem inactivation method (mCIM), and ethylenediamine tetraacetic acid (EDTA)-modified carbapenem inactivation method (eCIM).

Results: Out of 110 isolates, 66% (72/110) were carbapenem-resistant (suggestive of carbapenemase producers) by Kirby-Bauer disk diffusion but 58% (42/72) of Klebsiella isolates were confirmed for carbapenemase production by mPCR. Maximum number of carbapenemase gene were New Delhi metallo-β-lactamase (NDM) 52% (N = 22), 29% (N = 12) coproducers (NDM+OXA-48), and lowest in oxacillinase (OXA-48), 19% (N = 8). The overall sensitivity of MHT and mCIM+eCIM was 62% and 93%, and specificity was 88% and 97%, respectively. Our study showed that moderate biofilm producers were 51% (N = 56) K. pneumoniae isolates, strong biofilm producers 27% (N = 30), and 22% (N = 30) were weak/non-biofilm producers. We also found the correlation between biofilm formation and carbapenem-resistant K. pneumoniae (CR-KP) genes was statistically significant with a P value of 0.01*<0.05.

Conclusion: Most isolates of K. pneumoniae demonstrated a wide range of antibiotic resistance and were biofilm producers. Our results indicated that the combination of mCIM with eCIM showed high sensitivity and specificity to detect CR-KP compared with MHT.

Keywords: CR-KP - carbapenem-resistant Klebsiella pneumoniae; MBLs-Metallo-β-Lactamase; eCIM - ethylenediamine tetraacetic acid (EDTA)-modified carbapenem inactivation method; mCIM - modified carbapenem inactivation method; mPCR - multiplex real-time PCR.

Figure 1

Isolates 1 and 2 show mCIM and eCIM positive

Figure 2

Isolates 3 and 4 show positive mCIM and negative eCIM