Incidence of cholera-causing and non cholera-causing pathogenic vibrio species in the river-k and two of its feeder wastewater treatment plants in the Raymond Mhlaba municipality, Eastern Cape province of South Africa
- Authors: Gcilitshana, Onele
- Date: 2019
- Subjects: Water -- Purification -- South Africa -- Eastern Cape Effluent quality -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15145 , vital:40190
- Description: Despite technological advances in water treatment and improved sanitation in many developing countries, acute microbial diseases still thrive and continue to distress millions of people. This is due to the high number of rural dwellers that still source water for drinking and other domestic uses from contaminated rivers. In South Africa, there have been reports on waterborne disease outbreaks, and specifically in the area understudy, two records of diarrhoeal outbreaks associated with consumption of river water were reported within the last decade. All those outbreaks and previous reports on isolation of other pathogenic bacteria within the area necessitated the conduction of this study in order to identify the potential causes of the cholera-associate diarrheal outbreaks previously reported in the area and nationally. This study was designed to assess the incidence of cholera-causing and non-cholera causing pathogens in final effluents and surface waters of the Raymond Mhlaba Local Municipality, Eastern Cape Province, South Africa. RiverK which serves as a major resource for domestic activities, agricultural practices as well as an abstraction point for a potable water treatment plant was used for this study. River-K freshwater and final effluents of its two feeder wastewater treatment plants were sampled monthly, over a twelve-month period (December 2016–November 2017). For purposes of confidentiality, the names of the wastewater treatment plants and river involved are coded in this report. A total of 108 water samples were assessed for the physicochemical parameters that influence the presence of Vibrio pathogens. For bacteriology, the membrane filtration method followed by polymerase chain reaction (PCR) was adopted to assess the incidence of cholera-causing and non-choleracausing Vibrio pathogens, as well as their virulence-associated genes from the two wastewater treatment plants and their receiving waterbody (River-K). Antibiotic susceptibility profiles of identified Vibrio species were determined using the disc diffusion method against a panel of xvi sixteen antibiotics commonly used as antimicrobial drugs of Vibrio infections. Multiple antibiotics resistance index (MARI) and phenotypes (MARP) were measured, and the existence of antibiotic resistance genes was evaluated by PCR using specific primer sets. Most of the physicochemical parameters measured (pH, TDS, temperature, salinity and DO) complied with the recommended standards for drinking water, while some fell short of the recommended limits (EC, turbidity, TSS, free chlorine). From the presumptive Vibrio isolates, 64.3% (476/740) were confirmed by PCR, with their Vibrio densities across all sampling points ranging between 0 and 2.7 × 104 CFU/100 mL, with high counts recorded in summer, hence their positive significant correlation (P< 0.01) with temperature. From the confirmed Vibrio isolates, only V. cholerae (53/476), V. mimicus (21/476) and V. parahaemolyticus (5/476) were detected. For virulence-associated genes, virulence genes homologous to V. cholerae virulence determinants, namely ompU (35%), TCP (14%), ACE (11%), ctx (7%) and HylA (4.5%) were widespread (independently) amongst the V. cholerae and V. mimicus species, while V. parahemolyticus isolates (100%) produced only the ToxR gene. Antibiogram profiling found resistance against some antibiotics such as Nalidixic acid (65%), Polymyxin B (43.8%) etc. The MAR indices ranged between 0 and 0.67 with 41.3% of the isolates recording MAR index values above 0.2. The results presented high degrees of MARPs ranging from four to eleven antimicrobials. For resistance gene detection, the SXT element was detected in 66% of the isolates, while cat1 (93%) was the most predominant, followed by aac (68%), ant (61%), with bla-V (7.1%) as the least detected gene. Findings from this study suggest that the wastewater effluents from the two wastewater treatment plants are potential sources of pathogenic Vibrio species and River-K contains a high quantity of pathogenic Vibrio species with fluctuating seasonal variations that reaffirm temperature as a strong reason for their abundance. The antibiotic-resistant Vibrio species isolated here carry a pool of virulence-associated genes and xvii antibiotic resistance genes, presenting a health threat to the communities that use it directly for domestic and irrigation purposes. In conclusion, some surface waters in the Eastern Cape Province, South Africa are widely contaminated with cholera-causing and non-cholera causing Vibrio pathogens; furthermore, some wastewater treatment plants are ineffective in adequately removing microbial contaminants and have become sources of pathogenic bacteria to their receiving waterbodie
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- Date Issued: 2019
Quality indices of the final effluents of two sub-urban-based wastewater treatment plants in Amathole District Municipality in the Eastern Cape Province of South Africa
- Authors: Gcilitshana, Onele
- Date: 2014
- Subjects: Whole effluent toxicity testing -- South Africa -- Eastern Cape , Sewage disposal plants -- South Africa -- Eastern Cape , Water -- Purification -- South Africa -- Eastern Cape , Effluent quality -- Testing , Viruses -- South Africa -- Eastern Cape , Water reuse -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11288 , http://hdl.handle.net/10353/d1019816 , Whole effluent toxicity testing -- South Africa -- Eastern Cape , Sewage disposal plants -- South Africa -- Eastern Cape , Water -- Purification -- South Africa -- Eastern Cape , Effluent quality -- Testing , Viruses -- South Africa -- Eastern Cape , Water reuse -- South Africa -- Eastern Cape
- Description: Worldwide, water reuse is promoted as an alternative for water scarcity, however, wastewater effluents have been reported as possible contaminants to surface water. The failure of some wastewater treatment processes to completely remove organic matter and some pathogenic microorganisms allows them to initiate infections. This manifests more in communities where surface water is used directly for drinking. To assess water quality, bacteria alone cannot be used as it may be absent in virus-contaminated water. This study was carried out to assess the quality of two wastewater treatment plant effluents from the Eastern Cape Province of South Africa. Physicochemical parameters and microbiological parameters like faecal coliforms, adenovirus, rotavirus, hepatitis A virus, norovirus and enterovirus were evaluated over a projected period of one year. Physicochemical parameters were measured on site using multiparameters, faecal coliforms enumerated using culture-based methods and viruses are detected using both conventional and real-time PCR. Physicochemical parameters like electrical conductivity, turbidity, free chlorine and phosphates were incompliant with the standards set by the Department of Water affairs for effluents to be discharged. Faecal coliform counts were nil for one plant (WWTP-R) where they correlated inversely (P < 0.01) with the high free chlorine. For WWTP-K, faecal coliforms were detected in 27% of samples in the range of 9.9 × 101 to 6.4× 104 CFU/100ml. From the five viruses assessed, three viruses were detected with Rotavirus being the most abundant (0-2034176 genome copies/L) followed by Adenovirus (0–275 genome copies/L) then Hepatitis A virus (0–71 genome copies/L) in the WWTP-K while none of the viruses was detected in WWTP-R. Species B, species C and Adv41 serotypes were detected from the May 2013 and June 2013 samples where almost all parameters were incompliant in the plant. The detection of these viruses in supposedly treated effluents is suggestive of these being the sources of contamination to surface water and therefore renders surface waters unsafe for direct use and to aquatic life. Although real-time PCR is more sensitive and reliable in detection of viruses, use of cell-culture techniques in this study would have been more efficient in confirming the infectivity of the viruses detected, hence the recommendation of these techniques in future projects of this nature.
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- Date Issued: 2014