- Title
- Appraisal of wastewater final effluents and river water as reservoirs of cholera and non-cholera causing vibrio species : case study of the Amatole and OR Tambo District Municipalities
- Creator
- Nontongana, Nolonwabo
- Subject
- Vibrio -- South Africa -- Eastern Cape Vibrio cholerae Disease Reservoirs
- Date
- 2018
- Type
- Thesis
- Type
- Doctoral
- Type
- Microbiology
- Identifier
- http://hdl.handle.net/10353/9929
- Identifier
- vital:35146
- Description
- Vibrio infections remain a serious threat to public health. In the last decade, Vibrio disease outbreaks have created a painful awareness of the personal, economic, societal, and public health costs associated with the impact of inadequately treated wastewater effluents. This study was therefore designed to assess the occurrence of cholera and non-cholera causing Vibrio species in the final effluents of wastewater treatment plants and river waters in the Amatole (BT WWTP) and OR Tambo District municipalities (MT WWTP and QN River) of the Eastern Cape Province. Samples were collected monthly from December 2016 to November 2017 from the final effluent, 500 meters upstream and downstream of the discharge points and analysed for physicochemical parameters, Vibrio pathogens prevalence and their antibiogram characteristics using both culture-based and molecular techniques. Samples were collected aseptically using sterile 1L glass bottles containing 0.5 ml of sterile sodium thiosulphate solution and transported on ice to the laboratory for analyses within 6hrs of collection. The membrane filtration method was used for enumeration of presumptive Vibrio densities on thiosulfate citrate bile salt (TCBS) agar plates. Polymerase chain reaction (PCR) was then used to confirm the identities of the presumptive Vibrio species using the species-specific primers. The confirmed isolates were further subjected to molecular characterization to confirm their respective pathotypes. Antimicrobial susceptibility testing was done by the standard disc diffusion method recommended by the Clinical and Laboratory Standards Institute. The recovered Vibrio species were tested against a panel of 17 antibiotics. Physicochemical parameters measured include pH, temperature, electrical conductivity, salinity, turbidity, total dissolved solid (TDS), dissolved oxygen (DO), biochemical oxygen demand (BOD) and chlorine (only for BT WWTP). Unacceptably high levels of the assayed parameters were observed in many cases for TDS (66 - 879 mg/l), turbidity (2.0 -722.33 NTU) and DO (2.5 – 9.7 mg/l) as well as chlorine (0.2 – 3.2 mg/L). Presumptive Vibrio densities varied from 2.91 to 3.91 log10 CFU/100 ml and 2.67 to 3.18 log CFU/100ml, for BT WWTP and MT WWTP respectively. The densities for the QN River ranged between 2.51 to 3.99 log10 CFU/100mL. Out of 720 presumptive isolates recovered, 619 (86 percent) were found to be positive for the Vibrio genus. Molecular confirmation of the presumptive Vibrio species revealed the presence of V. fluvialis (16), V. vulnificus (12), V aliginolyticus (9), V. parahaemolyticus (37) and V. cholerae (5) isolates were confirmed. The susceptibility against 17 different antibiotics by the recovered species were examined. V. cholerae was notably resistant against nalidixic acid (3) and Ampicilin (2), all the V. vulnificus isolates were resistant against ampicillin (16), V. fluvialis showed resistance against ciprofloxacin and nalidixic acid, all (9) isolates for V. alginolyticus were resistant against ampicillin. V. parahaemolyticus showed resistance against cefutoxime (16), cefuxime (8) and ampicillin (13). The recovery of Vibrio in the discharged effluents throughout the sampling period even in adequately disinfected effluents is not acceptable considering that Vibrio are pathogenic bacteria. The findings of this study underline the need for constant monitoring of the physicochemical and microbiological qualities of discharged effluents and might also be suggestive for a review of the disinfection methods used at the treatment works as this might pose adverse health risk to the communities which still rely heavily on these surface waters.
- Format
- 97 leaves
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details | SOURCE1 | PhD thesis Nontongana 2018_final.pdf | 1 MB | Adobe Acrobat PDF | View Details |