Abstract
This study was undertaken to determine the virulence and antibiotic resistance profiles of diarrhoeagenic Escherichia coli (DEC) in environmental waters of Johannesburg, South Africa. Samples were collected and cultured on selective media. An 11-plex PCR assay was used to differentiate five DEC, namely: enteroaggregative (EAEC), enterohaemorrhagic (EHEC), enteroinvasive (EIEC), enteropathogenic (EPEC) and enterotoxigenic (ETEC). The antibiotic resistance profile of isolates was determined using the VITEK®-2 automated system. The virulence profiles of 170 E. coli tested showed that 40% (68/170) were commensals and 60% (102/170) were pathogenic. EPEC had a prevalence of 19.2% (32/170), followed by ETEC 11.4% (19/170), EAEC 6% (10/170) and EHEC 3% (5/170). Hybrid DEC carrying a combination of simultaneously two and three pathogenic types was detected in twenty-eight and nine isolates, respectively. The antibiotic susceptibility testing showed isolates with multidrug resistance, including cefuroxime (100%), ceftazidime (86%), cefotaxime (81%) and cefepime (79%). This study highlighted the widespread occurrence of DEC and antibiotic resistance strains in the aquatic ecosystem of Johannesburg. The presence of hybrid pathotypes detected in this study is alarming and might lead to more severe diseases. There is a necessity to enhance surveillance in reducing the propagation of pathogenic and antibiotic-resistant strains in this area.
Highlights
PCR assay confirmed 170 E. coli isolates with the detection of the mdh housekeeping gene
Singleplex PCRs were run on all hybrid isolates as confirmatory tests and the results showed the presence of the single genes detected by different pathogenic types (Supplementary Materials)
Further tests including sequencing would need to be performed on these isolates for the detection of extended-spectrum beta-lactamases, carbapenemases and plasmid-mediated colistin antibiotic resistance genes. This present study highlighted the widespread occurrence of potentially diarrhoeagenic Escherichia coli (DEC) and antibiotic resistance genes in the aquatic ecosystem of Johannesburg, South Africa
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Diarrhoea is one of the common causes of morbidity and mortality among infants and children in most developing countries [1]. 526,000 deaths of children younger than five per year [2,3]. Escherichia coli (E. coli) is an anaerobic Gram-negative, typically rod-shaped bacterium considered as part of the normal flora of the gut of humans and warm-blooded animals, and can be found in the environment, e.g., in water and soil [4,5].
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