University College Hospital, Ibadan, Nigeria
*1,2Jugah, C. C., 1,3Makanjuola, O. B., 1Ogunleye, V. O., 4Azuh, V. O., 4Kazeem, O. S.,
1,4Subulade, A. A., 4Adesanya, O. A., 4Adeniyi, A. V, and 1,3Kehinde, A. O.
1Department of Medical Microbiology and Parasitology, College of Medicine, University of Ibadan, Nigeria
2College of Medicine, University of Ibadan, Nigeria
3University College Hospital, Ibadan, Nigeria
4Biorepository and Clinical Virology Laboratory, College of Medicine, University of Ibadan, Nigeria *Correspondence to: christianaokiyi25@gmail.com
Abstract:
Background: Failure of antimicrobial therapy may give an insight into carriage of resistance genes among microbial pathogens. The ease of spread of these genes including beta-lactamase genes such as blaNDM, blaKPC, and blaOXA-48 is a major public health challenge worldwide. The study aimed to detect New Delhi metallo-β-lactamase (blaNDM) gene carriage among multidrug-resistant (MDR) Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa isolates from clinical specimens at the University College Hospital, Ibadan (UCH), Ibadan, Nigeria.
Methodology: This was a laboratory-based study of 110 presumptively identified Gram-negative bacterial isolates at the routine microbiology laboratory of UCH Ibadan, Nigeria between May and August 2021. The isolates were reidentified and confirmed as E. coli, K. pneumoniae and P. aeruginosa using biochemical tests, including oxidase test, cetrimide agar test, and Analytical Profile Index (API) system. Antibiotic susceptibility test of confirmed isolates to selected antibiotics was done using the modified Kirby-Bauer disk diffusion method and multi-drug resistance was defined as resistance to 3 or more antibiotic classes. The blaNDM was detected among the MDR isolates by conventional polymerase chain reaction using specific primers. Descriptive statistics were used to summarize variables, and Chisquare was used to compare categorical variables, with p value ≤ 0.05 taken to be statistically significant.
Results: Of the total 110 Gram-negative bacilli collected from the routine microbiology laboratory, 90 were confirmed as the Gram-negative bacilli of interest, with K. pneumoniae (58.9%, n=53), E. coli (31.1%, n=28) and P. aeruginosa (10.0%, n=9). Majority of the isolates (n=77, 85.6%) were susceptible to ertapenem, while most were resistant to ciprofloxacin (n=75, 83.3%), and 64 (71.1%) were multidrug-resistant. Among the MDR isolates, NDM carriage rate was 12.5% (n=8/64), with the carriage rate highest in P. aeruginosa (50.0%, n=1/2), followed by K. pneumoniae (13.6%, n=6/44) and E. coli (5.6%, n=1/18) but no significant difference in the carriage rate (x2=3.417, p=0.1811).
Conclusion: This study shows a high prevalence of MDR Gram-negative bacilli, with K. pneumoniae being the highest. Resistance was mostly observed to ciprofloxacin, while most isolates were susceptible to ertapenem. blaNDM gene was detected in all the three MDR bacterial pathogens. Emphasis should be placed on rational antibiotic use and routine susceptibility testing, including resistance gene detection, to guide therapy, and prevent emergence of multidrug resistance in microbial population.
Keywords: Multi-drug resistance, New Delhi metallo-β-lactamase, Carriage, Gram-negative bacilli
Download this Article in PDF format below