High prevalence of multiple-antibiotic-resistant (MAR) Escherichia coli in river bed sediments of the Apies River, South Africa

Abstract

This study aimed at investigating the presence of antibiotic-resistant Escherichia coli in river bed sediments of the Apies River, Gauteng, South Africa, in order to better inform health management decisions designed to protect users of the river. Overall, 180 water and sediment samples were collected at 10 sites along the Apies River from January to February 2014. E. coli was enumerated using the Colilert® 18/Quanti-Tray® 2000 (IDEXX). Isolates were purified by streaking on eosin methylene blue agar followed by the indole test. Pure E. coli isolates were tested for resistance to nine antibiotics by the Kirby-Bauer disc diffusion method. Over 98% of the isolates were resistant to at least one of the antibiotics tested. The highest resistance was observed against nitrofurantoin (sediments) and ampicillin (water). Over 80% of all resistant isolates showed multiple antibiotic resistance (resistance to ≥3 antibiotics). The abundance of E. coli in the sediments not only adds to the evidence that sediments are a reservoir for bacteria and possibly other pathogens including antibiotic-resistant bacteria but also suggests that antibiotic-resistant genes could be transferred to pathogens due to the high prevalence of multiple-antibiotic-resistant (MAR) strains of E. coli observed in the sediment. Using untreated water from the Apies River following resuspension for drinking and other household purposes could pose serious health risks for users. Our results suggest that river bed sediments could serve as reservoirs for MAR bacteria including pathogens under different climatic conditions and their analysis could provide information of public health concerns.

Quantification and Multidrug Resistance Profiles of Vancomycin-Resistant Enterococci Isolated from Two Wastewater Treatment Plants in the Same Municipality

“…Nitrofurantoin resistance was more common in the FE of the CAS system and was most often associated with E. faecium. Resistance to nitrofurantoin requires both the acquisition of genes for plasmid-mediated efflux pumps and mutations in genes for oxygen-insensitive nitroreductases and riboflavin/flavin mononucleotides [72,73]. Resistance to nitrofurantoin in E. coli isolated from water and sediments has started to gain attention and some suggestions for environmental and clinical surveillance of nitrofurantoin resistance have been proposed [73].…”

Mixed Aetiology of Diarrhoea in Infants Attending Clinics in the North-West Province of South Africa: Potential for Sub-Optimal Treatment

“…All confirmed A. butzleri samples were assessed for the presence of the cadF (Campylobacter invasion protein B) and ciaB genes (Campylobacter adhesin to fibronectin F), with primers and conditions described by Ghunaim et al [104]. For each reaction, a total of 10 µL of SensiFAST TM HRM Master Mix (Bioline GmbH, Luckenwalde, Germany), to which 0.5 µL (final concentration 0.5 µm) of each of the primer sets (Forward and reverse), 3 µL of template DNA and 1 µL of NF H 2 O was added.…”

Antibiotic Resistance Profile and Clonality of E. coli Isolated from Water and Paediatric Stool Samples in the North-West, Province South Africa

“…The supernatant was then extracted and analysed as the water sample. After incubation at 37°C, presumptive E. coli isolates were harvested from fluorescent Quanti-trays wells and streaked onto EMB agar to obtained pure colonies as previously described 47 . Purified colonies were stored at -80 o C in a 50% glycerol for further analysis.…”

“…DNA was extracted from selected colonies after 24 h, by the heat lysis method as previously described 48 . Extracted DNA templates were first examined for the presence of the malate dehydrogenase (mdh) gene to confirm the isolates as being E. coli 47 . Isolates harbouring the mdh gene were further separated into five DEC pathotypes, EPEC, EAEC,EIEC, ETEC, EHEC targeting specific VGs through multiplex and singleplex PCR assays and using primers and PCR-cycling conditions described by Abia et al 6 .…”

“…Multi-resistance in this study was defined as the resistance of E. coli to three or more antibiotics 47 . MAR was observed in 87.5% and 80.8% of isolates from human and water samples respectively.…”