Phenotypic and Molecular Characterization of Carbapenem-Resistant Enterobacteriaceae from Clinical Bacterial Isolates: A Multicenter Retrospective Chart Review Study in western of Saudi Arabia

Abstract

Background: Carbapenemase-producing bacteria are a major health problem because of its limited treatment options. Carbapenem-Resistant Enterobacteriaceae (CRE) are non-susceptible to carbapenem, which serves as the most potent class of antimicrobial agents available for multidrug-resistant bacterial infections. The aim of our study was to determine the prevalence of CRE and determine the type of carbapenemase genes present among patients in tertiary care hospitals in Jeddah, Saudi Arabia.Methods: We performed a retrospective chart review on 180 patients in two sites. Primarily, we evaluated the prevalence of KPC, NDM, VIM, OXA-48, and IMP genes of CRE from clinical isolates tested by Xpert® Carba-R. Secondly, we assessed the prevalence of CRE based on antibiogram reports and described the susceptibility of CRE and the aforementioned CRE genes to antimicrobial agents.Results: CRE clinical isolates showed no occurrence of KPC, VIM, and IMP genes. OXA-48 gene was predominantly prevalent, with 76.1%, followed by NDM 13.9%, and both genes co-existed in 6.1% of the isolates. The CRE percent prevalence in one site in 2017 was 3.8%, and increased to 6.03% in 2018, whereas in the second site, the percentage was much higher, reaching 22.9% in 2018 and 18.9% in 2019. The CRE prevalence was dominated by Klebsiella pneumoniae (K. pne), occurring in 92.8% of the isolates, followed by E. coli in 6.7%. K. pne showed a higher frequency of OXA-48 (79%) than NDM (11.7%) genes, with a p-value of 0.007, while E. coli showed an equal frequency of both genes (41.7%). K. pne and E. coli showed high antimicrobial resistance to imipenem, meropenem, tazocin, and ciprofloxacin. However, they showed less resistance to amikacin, gentamycin, and tigecycline. NDM and OXA-48 genes showed 100% resistance to imipenem, meropenem, tazocin, ciprofloxacin and amikacin and the lowest resistance to gentamycin, tigecycline, and colistin.Conclusion: Over the two year retrospective study period, the CRE percent prevalence in the evaluated clinical isolates has remarkably increased. K. pne and E. coli were the most prevalent CRE organisms with OXA-48 and NDM as the predominant genes. CRE organisms and genes showed high antimicrobial resistance to imipenem, meropenem and tazocin, and lower resistance to gentamycin and tigecycline.