Identification and antimicrobial resistance prevalence of pathogenic Escherichia coli strains from treated wastewater effluents in Eastern Cape, South Africa

Abstract

Antimicrobial resistance (AMR) is a global problem impeding the effective prevention/treatment of an ever‐growing array of infections caused by pathogens; a huge challenge threatening the achievements of modern medicine. In this paper, we report the occurrence of multidrug resistance (MDR) in Escherichia coli strains isolated from discharged final effluents of two wastewater treatment facilities in the Eastern Cape Province of South Africa. Standard disk diffusion method was employed to determine the antibiotic susceptibility profile of 223 polymerase chain reaction (PCR)‐confirmed E. coli isolates against 17 common antibiotics in human therapy and veterinary medicine. Seven virulence associated and fourteen antibiotic resistance genes were also evaluated by molecular methods. Molecular characterization revealed five pathotypes of E. coli in the following proportions: enterotoxigenic ETEC (1.4%), enteropathogenic EPEC (7.6%), enteroaggregative EAEC (7.6%), neonatal meningitis (NMEC) (14.8%), uropathogenic (41.7%), and others (26.9%). Isolates showed varying (1.7–70.6%) degrees of resistance to 15 of the test antibiotics. Multidrug resistance was exhibited by 32.7% of the isolates, with the commonest multiple antibiotic‐resistant phenotype (MARP) being AP‐T‐CFX (12 isolates), while multiple antibiotic‐resistant indices (MARI) estimated are 0.23 (Site 1) and 0.24 (Site 2). Associated antibiotic resistance genes detected in the isolates include: strA (88.2%), aadA (52.9%), cat I (15%), cmlA1 (4.6%), bla TEM (56.4%), tetA (30.4%), tetB (28.4%), tetC (42.2%), tetD (50%), tetK (11.8%), and tetM (68.6%). We conclude that municipal wastewater effluents are important reservoirs for the dissemination of potentially pathogenic E. coli (and possibly other pathogens) and antibiotic resistance genes in the aquatic milieu of the Eastern Cape and a risk to public health.

Ecological and Public Health Implications of the Discharge of Multidrug-Resistant Bacteria and Physicochemical Contaminants from Treated Wastewater Effluents in the Eastern Cape, South Africa

“…E. coli, Shigella, Salmonella and Vibrio spp. have been the predominant pathogens linked to waterborne outbreaks in Africa [21,22], whereas certain clonal strains of these pathogens have been reported to survive conventional wastewater treatment processes [23][24][25][26].…”

Resistance genes to sulphonamide in commensal Escherichia coli isolated from stool of patients in Mansoura University Children Hospital

“…Normal bacterial flora like E. coli is usually used as an index of transmission and spread of the gained resistant determinant (Adefisoye and Okoh, 2016).…”

“…Actually, a great prevalence of decreased response to antibiotics is usually recorded in screening assays of different bacterial strains (Shears, 2001), and in researches that examined normal bacterial flora as an important index for distribution of genes that are responsible for decreased response to antibiotics (Alves et al, 2014). In addition, developing localities usually suffer from the bad impact of antibiotic resistance on disease outcome and rates of mortality which is due to recurrent infections by bacteria and the great value of antibiotics in fighting them (Adefisoye and Okoh, 2016). Treatment of many human diseases was greatly dependent on sulphonamid drugs, but, sulphonamides were usually added to trimethoprim in order to decrease the appearance of resistance, this usually limits the prescription of these drugs that have the advantage of being low cost.…”

Assessment of the prevalence of enteric viruses in the final effluents of two peri-urban wastewater treatment plants

“…In addition, research has shown a lack of correlation in the presence of viral pathogens and faecal indicator bacteria [9,10] whose sole presence or absence cannot be used to accurately predict the presence of other pathogens such as protozoan parasites and enteric viruses which are highly infectious in low doses [11]. Most sewage treatment plants fail to completely remove enteric viruses from wastewater either due to the resistance of viruses to adverse conditions or simply because the treatment plants are generally not designed to remove viral pathogens as they are to reduce the biochemical oxygen demand levels of the wastewater [12]. In South Africa, wastewater in rural areas and small towns often receives partial or minimal treatment [13,14].…”

“…The viral nucleic acids were concentrated by the adsorptionelution method of Haramoto et al [22] as modified using a negatively charged Millipore filter membrane (Merck, Ireland) [12]. Briefly, …”