Analysis of antimicrobial resistance genes encoding extended-spectrum β-lactamases in pathogenic bacteria isolated from wounds of diabetes mellitus patients at Jaramogi Oginga Odinga Teaching & Referral Hospital, Kenya.

Abstract

The number of people with diabetes in the world is estimated to increase to 783 million by 2045 with prevalence in Africa and Kenya estimated at 54.9 million (5.2%) and 1.5milion (4.5%) by 2045 respectively. At Jaramogi Oginga Odinga Teaching and Referral Hospital (JOOTRH), diabetes is the sixth cause of mortality. The threat to an individual with diabetes developing a wound is 25% with infected wounds being polymicrobial. Worldwide, Staphylococcus aureus, Proteus species, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli are the most common pathogens isolated from diabetic wounds. At JOOTRH, diabetic wounds are managed using penicillins, cephalosporins, aminoglycosides and carbapenems. Most common genetic variants of the pathogens worldwide include temoneira (TEM), sulphydryl variable (SHV), cefotaximase (CTX-M), pseudomonas extended-resistance (PER), Oxacillinase (OXA), mecA and vanA. Several studies show contradicting views with regard to; the most common bacteria colonizing wounds, the resistance patterns of bacteria to antibiotics and more importantly studies on resistant genes encoding extended spectrum β-lactamases in bacteria show varied occurrence of genes from region to region. These variations complicate efforts to single out the most prevalent microbes, their resistance patterns and which gene is most common for precipitating antimicrobial resistance thus calling for continued research especially in areas such as JOOTRH where no such study has been conducted. The purpose of this study was analysis of antimicrobial resistance genes encoding extended spectrum β-lactamases in pathogenic bacteria isolated from wounds of diabetes mellitus patients at JOOTRH. Specific objectives were to; phenotypically profile selected bacteria microbe, determine antimicrobial resistance patterns and genetic diversity of resistant genes encoding extended spectrum β-lactamases in bacteria isolated from wounds of diabetes mellitus patients at JOOTRH. A hospital based cross sectional study design was employed with a target population of 168 and sample size of 117 patients sampled using stratified random sampling. Data was collected using a structured questionnaire and a laboratory form for a period of 6 months. Pus swabs were collected for isolation of bacteria using conventional techniques and serology. Susceptibility was done using Kirby-Bauer disk diffusion on Mueller Hinton Agar at 37˚C for 24 hrs. Antimicrobial resistance genes encoding ESBLs were identified by Polymerase Chain Reaction and High Resolution Melting Analysis. Chi-square test analyzed prevalence, antimicrobial susceptibility in relation to clinico-demographics while independent samples t-test and binary regression analysis established relationship between resistant genes and inhibition zones. Results showed that Gram negative were most prevalent at 65.8% with 62.4% being ESBLs producers. Low resistance was established for; amikacin (7.5%) and gentamicin (7.5%) on S. aureus , imipenem (0.0%) and gentamicin (0.0%) on E. coli, imipenem (0.0%) on K. pneumoniae and Proteus mirabilis and ciprofloxacin (0.0%) on P. aeroginosa. The diverse genes present were blaSHV (17.8%), blaTEM (17.8%), blaCTX-M (10.3%), EcoblaTEM (5.3%), blaPER (10.3%), mecA (30.8%) and VanA (7.7%) with mecA being most prevalent. Findings provide effective chemotherapeutic alternatives including aminoglycosides, carbapenems and fluoroquinolones for managing diabetes patients with wounds and recommends that JOOTRH to adopt microbial screening, susceptibility and gene testing policy for the purpose of identifying the most effective treatment regimen for better patient’s care.