Biocide resistant and antibiotic cross-resistant potential pathogens from sewage and river water from a wastewater treatment facility in the North-West, Potchefstroom, South Africa

• Published in: Water science and technology Vol. 80; no. 3; pp. 551 - 562
• Main Authors: Mann, B C, Bezuidenhout, J J, Bezuidenhout, C C
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01-08-2019
• Subjects: Aeromonas; Anti-Bacterial Agents; Antibiotic resistance; Antibiotics; Antimicrobial agents; Automation; Bacteria; Biocides; Chloroxylenol; Chromatography; Deoxyribonucleic acid; Disease resistance; Disinfectants; DNA; Drug resistance; Drug Resistance, Bacterial - genetics; Enzymes; Extracellular; Extracellular enzymes; Fingerprinting; Genes; Heavy metals; High performance liquid chromatography; HPLC; Liquid chromatography; Metals; Microbial Sensitivity Tests; Microbiological strains; Microbiology; Nucleotide sequence; Organic chemistry; Pathogens; PCR; Personal grooming; Preservatives; Profiles; River water; Rivers; Sewage; Sewage bacteria; South Africa; Thermal cycling; Triclosan; Virulence; Waste Disposal, Fluid; Waste Water - microbiology; Wastewater treatment; Wastewater treatment plants; Water treatment; Water treatment plants; South Africa; United Kingdom > UK; United States > US; Germany; Wales
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2019.300

Exposure to antibiotics, biocides, chemical preservatives, and heavy metals in different settings such as wastewater treatment plants (WWTPs) may apply selective pressure resulting in the enrichment of multiple resistant, co- and cross-resistant strains of bacteria. The purpose of this study was to identify and characterize potentially pathogenic triclosan (TCS) - and/or, chloroxylenol (PCMX) tolerant bacteria from sewage and river water in the North-West, Potchefstroom, South Africa. Several potential pathogens were identified, with Aeromonas isolates being most abundant. Clonal relationships between Aeromonas isolates found at various sampling points were elucidated using ERIC-PCR. Selected isolates were characterized for their minimum inhibitory concentrations against the biocides, as well as antibiotic resistance profiles, followed by an evaluation of synergistic and antagonistic interactions between various antimicrobials. Isolates were also screened for the presence of extracellular enzymes associated with virulence. High-performance liquid chromatography revealed the presence of both biocides in the wastewater, but fingerprinting methods did not reveal whether the WWTP is the source from which these organisms enter the environment. Isolates exhibited various levels of resistance to antimicrobials as well as several occurrences of synergy and antagonisms between the biocides and select antibiotics. Several isolates had a very high potential for virulence but further study is required to identify the specific virulence and resistance genes associated with the isolates in question.