Municipal wastewater effluents as a source of listerial pathogens in the aquatic milieu of the Eastern Cape Province of South Africa: a concern of public health importance.
We evaluated the effluent quality of an urban wastewater treatment facility in South Africa and its impact on the receiving watershed for a period of 12 months. The prevalence and antimicrobial susceptibility of potential Listeria pathogens (L. ivanovii and L. innocua) and the physicochemical quality of the treated wastewater effluent was assessed, with a view to ascertain the potential health and environmental hazards of the discharged effluent. Total listerial density varied between 2.9 x 10(0) and 1.2 x 10(5) cfu/mL; free living Listeria species were more prevalent (84%), compared to Listeria species attached to planktons (59-75%). The treated effluent quality fell short of recommended standards for turbidity, dissolved oxygen, chemical oxygen demand, nitrite, phosphate and Listeria density; while pH, temperature, total dissolved solids and nitrate contents were compliant with target quality limits after treatment. The Listeria isolates (23) were sensitive to three (15%) of the 20 test antibiotics, and showed varying (4.5-91%) levels of resistance to 17 antibiotics. Of seven resistance gene markers assayed, only sulII genes were detected in five (22%) Listeria strains. The study demonstrates a potential negative impact of the wastewater effluent on the receiving environment and suggests a serious public health implication for those who depend on the receiving watershed for drinking and other purposes.
Odjadjare
Emmanuel E O
EE
Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X1314, Alice, South Africa. eodjadjare@ufh.ac.za
Obi
Larry C
LC
Okoh
Anthony I
AI
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D017931:DNA Primers; D006801:Humans; D007220:Industrial Waste; D008087:Listeria / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D011634:Public Health; D013019:South Africa; D014871:Water Microbiology
D000900:Anti-Bacterial Agents; D017931:DNA Primers; D007220:Industrial Waste