Abstract
BackgroundThe World Health Organization (WHO) recently classified Enterobacteriaceae resistance to third-generation cephalosporin into the group of pathogens with critical criteria for future research.MethodsA study to assess the antibiogram and beta-lactamase genes among the cefotaxime resistant E. coli (CREc) from a South African wastewater treatment plant (WWTP) was conducted using standard phenotypic and molecular biology characterization methods.ResultsApproximate total E. coli (TEc) concentration (log10 CFU/mL) ranged between 5.7 and 6.8 among which cefotaxime resistant E. coli were between 1.8 and 4.8 (log10 CFU/mL) for cefotaxime antibiotic concentration of 4 and 8 mg/L in the influent samples. Effluent samples, heavily influenced by the chlorination had only 0.3 log10 CFU/mL of TEc. Fifty-one cefotaxime resistant isolates were selected out of an overall of 75 isolates, and subjected to a new round of testing, with a follow up of 36 and 48 isolates for both colistin and gentamicin, respectively as guided by initial results. Selected CREc exhibited resistance to amoxicillin-clavulanic acid (35.3%; n = 51), colistin sulphate (76.5%; n = 36), ciprofloxacin (47.1%; n = 51), gentamicin (87.5%; n = 48) and intermediate-resistance to meropenem (11.8%; n = 51). Extended spectrum-beta-lactamase genes detected, viz.: blaCTX-M (52.6%; n = 38) and blaTEM (84.2%; n = 38) and concurrent blaCTX-M + blaTEM (36.8%; n = 38), but no blaSHV was detected. Carbapenem resistance genes, blaKPC-2 (15.8%; n = 38), blaOXA-1 (57.9%; n = 38), blaNDM-1 (15.8%; n = 38) were also detected. Approximately, 10.5 - 36.8% (n = 38) co-occurrence of two or more beta-lactamase genes was detected in some isolates. Out of the selected number (n = 30), 7(23.3%) were enterotoxigenic E. coli (ETEC), 14 (46.7%) were Enteroaggregative E. coli (EAEC), but no enteropathogenic E. coli (EPEC) was detected.ConclusionResistance to cefotaxime and the presence of a wide range of beta-lactamase genes exposed the potential risks associated with these pathogens via occupational and domestic exposure during the reuse of treated wastewater.
Highlights
Escherichia coli has been accepted as both a biological indicator of water contamination and a human pathogen implicated in both systemic and superficial infections [1,2,3,4,5,6]
Varying concentrations of cefotaxime-resistant E. coli occurred with differences between the two concentrations of the antibiotic supplemented in the laboratory cultivation media
Since the Wastewater Treatment Plant (WWTP) are known as early warning systems [47], the Multiple antibiotic resistance (MAR) Indices in this study revealed that antibiotics are in constant abuse and their high selective pressure [61]
Summary
Escherichia coli has been accepted as both a biological indicator of water contamination and a human pathogen implicated in both systemic (e.g. septicemia, urinary tract infection, meningitis, etc) and superficial infections (skin or wound infection) [1,2,3,4,5,6]. E. coli is part of the normal flora of the gastrointestinal tract, shed along with faecal waste including release by infected and convalescent individuals through poorly managed wastewater [7, 8]. The public health impact of the E. coli released depends partly on the antibiotic susceptibility pattern of the organism, as this determines the clinical treatment option(s) available [9]. Park [10] inferred that resistance to third-generation cephalosporin and carbapenem by Gram-negative bacteria in the community is very difficult to manage. Koopmans et al [12] reported that cefotaxime is one of the two most used antibiotics in pediatric ward and pediatric intensive care unit of South African hospitals. The World Health Organization (WHO) recently classified Enterobacteriaceae resistance to thirdgeneration cephalosporin into the group of pathogens with critical criteria for future research
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
