Molecular characterization and distribution of cephalosporin resistance determinants in Escherichia coli and Klebsiella pneumoniae isolated from patients attending Kampala International University Teaching Hospital in Bushenyi, Western Uganda

Abstract

Cephalosporins are the first-line therapy antibiotics used in the treatment of gram-negative bacterial infections. However, high prevalence of cephalosporins resistance in Klebsiella pneumoniae and Escherichia coli has been reported worldwide. Studies conducted in Uganda reported high incidences of cephalosporin resistance (CR). Successive studies at Mulago National Referral Hospital indicated a decline in the resistance levels pointing to the need for regular antibiotic resistance surveillance. Therefore, this study carried out molecular characterization of CR determinants in E. coli and K. pneumoniae isolated from patients attending Kampala International University Teaching Hospital (KIU-TH). A retrospective study using E. coli and K. pnuemoniae samples previously obtained from surgical wounds and urinary tract infections among patients treated at KIU-TH between September 2016 and August 2018 was conducted. Biochemical assays were used to confirm the identity of the samples. Combined disc and boronic acid assays were used to determine the cephalosporine resistance profile of the isolates. Multiplex PCR amplification was used to characterize the extended spectrum betalactmase (ESBL) encoding genes. The study revealed that E. coli (130/81.2%) isolates were more predominant than K. pneumoniae (30/18.8%) among the archived samples. K. pneumoniae showed the highest phenotypic resistance with a mean prevalence of 90.6% but comparable to that of E. coli (89.3%). Of the 160 isolates screened, 105 (65.6%) were ESBL producers. Multiplex PCR revealed that the most predominant ESBL encoding gene was bla_SHV at a prevalence of 42.0%, followed by bla_TEM at 27.3%, bla_CTX-M at 22.4% and bla_CTX-M-15 at 8.4%. The incidence of phenotypic resistance and distribution of ESBL genes were significantly higher in patients of Ishaka division. Our study reports a high prevalence of cephalosporin-resistant E. coli and K. pnuemoniae isolated from patients attending KIU-TH and highlights the need forr routine screening of antimicrobial resistance in health-care facilities so as to guide clinicians on the rational prescription of antibiotics.
List of abbreviations: ATCC: American Type Culture Collection; ESBL: extended spectrum betalactmases; AmpC: aminopenicillin cephalosporinase; CTX-M: cephotaxime (M-first detected in Munich) hydrolyzing capabilities; CTX-M-U: cephotaxime hydrolyzing capabilities gene Universal primer; SHV: sulfhydryl variables (variant-2); CMY-2: cephamycins (variant-2); TEM: temoneira; ACT-1: AmpC type (variant-1); Bla: Beta lactam; DNA: deoxyribonucleic acid; PCR: Polymerase chain reaction; MNRH: Mulago National Referral Hospital; MRRH: Mbarara Regional Referral Hospital; KRRH: Kabale Regional Referral Hospital (KRRH); KIU-TH: Kampala International University Teaching Hospital; CDL: Central Diagnostic Laboratory; CoVAB: College of Veterinary Medicine, Animal Resources and Biosecurity; CR: cephalosporin resistance