Genotypic Diversity and Characterization of Quinolone Resistant Determinants from Enterobacteriaceae in Yaoundé, Cameroon

Background: Enterobacteriaceae causes many types of infections which are often treated with quinolones and fluoroquinolone (Q/FQ). The resistance mechanisms to Q/FQ are usually associated with mutations in the quinolone resistance determining region which alter the conformation of target amino acid residues within the protein and in the qnr genes. This study aimed at determining the antimicrobial resistant profile of a sample of Enterobacteriaceae from Cameroon and the genetic diversity in quinolone-resistant isolates in view of implementing a better management, treatment, control and prevention of the transmission of these resistant strains. Methods: Identification and antimicrobial susceptibility testing was done using VITEK 2. The detection of plamid-mediated quinolone resistance (PMQR) genes was carried out using the conventional PCR method. Sequencing was done using the Applied Biosystem 3500 genetic analyser. DNA fingerprint was obtained using Pulsed-Field Gel electrophoresis. Results: Among 440 Enterobacteriaceae, the most prevalent genera were: Escherichia 178/440 (39.5%);Klebsiella 148/440 (33.6%);Enterobacter 35/440 (8%);Pantoea 28/440 (6.4%);Proteus 14/440 (3.2%) Salmonella 13/440 (3%). Ampicillin resistance showed the highest prevalence with 371/440 (81%) and Imipenem the lowest resistance 9/440 (2.1%). The ciprofloxacin resistance rate was 161/440 (36.6%). The detected plasmid mediated quinolone resistance (PMQR) genes were: qnrA, 2/161 (1.2%);qnrB, 31/161 (19.3%);qnrS, 13/161 (8.1%): Aac (6')Ib-cr, 84/161 (52.2%) and qepA, 3/161 (1.9%). There were several mutations in the parC gene of Klebsiella leading to S80D and S80N substitutions. Two pairs of Klebsiella peumoniae strains were phenotypically and genotypically identical with 100% similarity in the dendrogramme. Conclusion: This study showed that quinolone resistance was high. The PMQR genes contributing to this resistance were diverse. This high PMQR indicates that there has been an unknown circulation of these genes in our community. To avoid the rapid dissemination of these PMQR genes continuous surveillance of antimicrobial resistance should be carried out not only in humans but also in animals to monitor the evolution of these genes.

High Prevalence of Multidrug Resistant <i>Klebsiella</i>Species Isolated from the Yaounde University Teaching Hospital, Cameroon

Background and Purpose: Klebsiella species are amongst the most common causes of a variety of community-acquired and hospital-acquired infections (HAI), characterized by high morbidity and mortality rates. Most infections caused by Klebsiella species are usually treated using antibiotics. The aim of this study was to determine the antimicrobial resistance profile of Klebsiella species isolated from in-patients and out-patients at the Yaounde University Teaching Hospital. The data generated will go a long way to improve on the choice of an adequate empiric antibiotic treatment for infections caused by Klebsiella species. Methodology: A cross-sectional descriptive study was carried out over a period of 6 months, spanning from February 2019 to July 2019 with a sample size of 37 isolates, obtained from 6 different clinical specimens. Identification of isolates was done using API 20E identification system (Biomerieux SA, Lyon, France). Susceptibility to antibiotics was tested as described by Kirby-Bauer in 1956. Inhibition diameters were interpreted according to recommendations from the European Committee on Antimicrobial Susceptibility Testing (EUCAST, 2019). Results and Conclusion: Among the 37 Klebsiella isolates identified, Klebsiella pneumoniae was the most prevalent species isolated with a percentage of 54.1%, followed by Klebsiella rhinoscleromatis 18.9%, Klebsiella ozaenae 16.2% and Klebsiella oxytoca, 10.8%. The resistance pattern of Klebsiella to amoxicillin, amoxicillin/clavulanate, tircacillin, tircacillin + clavulanic acid, piperacillin, piperacillin + tazobactam, cefalotin, cefuroxim, ceftazidime, cefotaxime, ceftriaxone, cefepime, imipenem, meropenem, aztreonam, amikacin, gentamicin, tobramycin, trimethoprim/ sulfamethoxazole, nalidixic acid, pipemidic acid, norfloxacin, ciprofloxacin, levofloxacin, ofloxacin, and moxifoxacin was as follows;100%, 86.5%, 97.3%, 83.6%, 86.5%, 16.2%, 86.5%, 83.8%, 78.4%, 32.4%, 78.4%, 76.7%, 2.7%, 2.7%, 76.7%, 13.5%, 75.7%, 73.0%, 91.9%, 51.4%, 48.6%, 64.9%, 48.6%, 48.6%, 73.0% and 62.2% respectively. Multidrug resistance was observed in 94.6% of the Klebsiella isolates. Conclusion: This study shows that the level of multidrug resistance is high. The isolates expressed good sensitivity to carbapenems, piperacillin + tazobactam, amikacin and high resistance to all other antimicrobials tested. Therefore, antimicrobial susceptibility testing prior to prescriptions should be encouraged and sensitization of the population about consequences of inappropriate antibiotic treatment and auto medication should be enforced as a means to curb antimicrobial resistance.