Browsing by Author "Okoh, Anthony"

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    Assessment of the Physicochemical Qualities and Prevalence of Escherichia coli and Vibrios in the Final Effluents of Two Wastewater Treatment Plants in South Africa: Ecological and Public Health Implications
    (Multidisciplinary Digital Publishing Institute, 2015-10-23) Osuolale, Olayinka; Okoh, Anthony
    The final effluents of two wastewater treatment plants (WWTPs) in the Eastern Cape Province of South Africa were evaluated for their physicochemical and microbiological qualities over a period of 12 months. The physicochemical parameters assessed ranged as follows both plants. The ranges of values for the physicochemical are: pH (3.9–8.6), total dissolved solids (86.50–336.3 mg/L), electrical conductivity (13.57–52.50 mS/m), temperature (13–28 °C), nitrate (0–21.73 mg/L), nitrite (0.01–0.60 mg/L), orthophosphate (1.29–20.57 mg/L), turbidity (4.02–43.20 NTU), free chlorine (0.05–7.18 mg/L), dissolve oxygen (3.91–9.60 mg/L), biochemical oxygen demand (0.1–9.0 mg/L) and chemical oxygen demand (4.67–211 mg/L). The microbiological assessment for both WWTPs revealed the presence of E. coli in counts ranging between 0 and 1.86 × 104 CFU/100 mL and Vibrio counts ranging between 0 and 9.93 × 103 CFU/100 mL. We conclude that these WWTPs are important point sources of pollution in surface water with potential public health and ecological risks.
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    Detection and antibiotic susceptibility of pathogenic Escherichia coli isolated from the final effluent of two wastewater treatment Plants in the Eastern Cape Province, South Africa
    (BioRxiv, 2017-07-24) Osuolale, Olayinka; Okoh, Anthony
    Wastewater is an important reservoir for Escherichia coli and can present significant acute toxicity if released into receiving water sources without being adequately treated. To analyze whether pathogenic E. coli strains that cause infections are in treated effluent and to recognize antibiotic profile. 476 confirmed isolates from two treatment Plants were characterized for the presence of various E. coli pathotypes. A total of 8 pathotypes were screened and only four were confirmed. UPEC was about 5.7% followed by EAEC at 2.3%, NMEC at 1.1% and EPEC at 0.6%. Antibiotic susceptibility patterns of E. coli pathotypes such as UPEC showed low resistance to antibiotics like meropenem (100%), cefotaxime (100%) and gentamicin (88.9%). The pathotype also showed high degrees of resistance to tetracycline (74.1%), ampicillin (74.1%) and cephalothin (66.7%). Other E. coli pathotypes, EAEC, NMEC and EPEC, showed high sensitivity (100%) to meropenem, gentamicin and cefotaxime, and varying degree of resistances to ampicillin, tetracycline and cephalothin. The results of this study reveal that the two Plants discharge effluents with pathogenic E. coli and are reservoir for the bacteria into receiving water sources. In summary, this finding raises the possibility that at least some pathogenic E. coli pathotypes are getting into the environment through WWTPs and represent potential route for enteropathogenic infection. In addition, certain pathotypes may have acquired resistance properties, becoming a potential cause of drug resistance infection. This study reveals inadequacy of the plants studied to produce effluents of acceptable quality
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    Human enteric bacteria and viruses in five wastewater treatment plants in the Eastern Cape, South Africa
    (Elsevier, 2017-02-04) Osuolale, Olayinka; Okoh, Anthony
    Monitoring effluents from wastewater treatment plants is important to preventing both environmental contamination and the spread of disease. We evaluated the occurrence of human enteric bacteria (faecal coliforms and Escherichia coli) and viruses (rotavirus and enterovirus) in the final effluents of five wastewater treatment plants (WWTPs) in the Eastern Cape of South Africa. Human viruses were recovered from the effluent samples with the adsorption–elution method and detected with singleplex real-time RT–PCR assays. Rotavirus was detected in several effluents samples, but no enterovirus was detected. At WWTP-C, rotavirus titre up to 105 genome copies/L was observed and present in 41.7% of the samples. At WWTP-B, the virus was detected in 41.7% of samples, with viral titres up to 103 genome copies/L. The virus was detected once at WWTP-E, in 9% of the samples analysed. The viral titres at WWTP-A were below the detection limit in all 25% of the 1.25 L samples in which the virus was detected. Rotavirus was not observed at WWTP-D. Faecal coliform bacteria and E. coli were detected in all the WWTPs, but no correlation was established between the enteric bacteria and viruses studied. The occurrence of rotavirus in effluent samples discharged into surface waters highlights the importance of assessing viral contamination in the water sources used for domestic water use.
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    Incidence of human adenoviruses and Hepatitis A virus in the final effluent of selected wastewater treatment plants in Eastern Cape Province, South Africa
    (BioMed Central, 2015-06) Osuolale, Olayinka; Okoh, Anthony
    Municipal effluent constitutes a large reservoir of human enteric viruses and bacteria. Contemporary monitoring practices rely on indicator bacteria, and do not test for viruses. Different viruses, including Norwalk-like viruses, Hepatitis A virus (HAV), adenoviruses, and rotaviruses, are important agents of illnesses in humans. The burden of disease caused by adenoviruses manifests as pneumonia, bronchiolitis, otitis media, conjunctivitis, and tonsillitis, whereas HAV infection can manifest as acute inflammatory diseases of the liver, fever, anorexia, malaise, nausea, and abdominal discomfort, followed by jaundice and dark urine. The public health implications of these viruses depend upon the physiological status of the wastewater microbial community.
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    Investigating the occurrence of E. coli O157:H7 in the final effluents of two wastewater treatment plants.
    (BioRxiv, 2018-07-07) Osuolale, Olayinka; Okoh, Anthony
    AIM: The final effluent of two wastewater plants located in the Eastern Cape of South Africa were tested for the presence of Enterohaemorrhagic Escherichia coli O157:H7 (E. coli O157:H7) isolates, and characteristics of the isolates obtained were determined. METHODS AND RESULTS: A total of 23 wastewater samples were collected from the treatment plants at the final effluent point after the disinfectant stages of wastewater processing. Altogether, 540 presumptive E. coli isolates were obtained by colony counting on the E. coli O157:H7 chromogenic agar base supplemented with cefixime tellurite and were sub-cultured onto sorbitol-MacConkey agar and tested for agglutination using the Prolex E. coli O157 latex test reagent kit. The results showed that the 149 suspected colonies from SMAC agar were all negative for the antisera. CONCLUSION: None of the isolates agglutinated with antisera against E. coli O157. Thus no presence of the bacteria can be confirmed from the treated effluents SIGNIFICANCE AND IMPACT OF STUDY: The likelihood of the receiving water body and the environment being contaminated with E. coli O157:H7 is therefore minimal.
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    Isolation and antibiotic profile of Vibrio spp. in final effluents of two wastewater treatment plants in the Eastern Cape of South Africa
    (bioRxiv, 2018-05) Osuolale, Olayinka O.; Okoh, Anthony
    Background: Poorly or partially treated wastewater disposed of can contaminate water and even properly treated sewage can have its problems. The highlight of this danger is wastewater treatment plants serving as reservoir for proliferation of antibiotic resistant organisms. We have reported the state of two wastewater treatment in the Eastern Cape of South Africa which discharge poorly and partially treated effluents. Our aims to identify Vibrio spp. and their antibiotic profiles in treated final effluent discharge from wastewater treatment plant. Methods: Culture based approach using the TCBS agar for isolation Vibrio spp., presumptive isolates were purified and confirmed using PCR. The confirmed isolated were also genotyped to identify the species present. The antibiotic profiling of the confirmed isolates was using the CLSI recommended first line antibiotics for Vibrio. Results: Out of the 786 presumptive isolates, 374 were confirmed as Vibrio spp. None of the Vibrio spp. pathotypes were present in the confirmed isolates. Randomized isolates of 100 Vibrio spp. were selected, > 90 % of the isolates were susceptible to Ciprofloxacin, and > 50 – 80 % for Ampicillin, Chloramphenicol, Tetracycline, Cefotaxime, and Trimethoprim-sulfamethoxazole respectively. Conclusions: We are able to isolate Vibrio spp. from treated effluents but none of their pathotypes were present. The antibiotic agents considered for primary testing which are ciprofloxacin was the most effective of the antibiotic drugs, followed by cefotaxime, tetracycline with less susceptibility. Contamination from discharged effluents from wastewater treatment can lead to spread of spread of disease in this environment. The WWTPs studied are sources of pollution to surface water with environmental and public health.
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    Prevalence and characterisation of non-cholerae Vibrio spp. in final effluents of wastewater treatment facilities in two districts of the Eastern Cape Province of South Africa: implications for public health
    (Springer Berlin Heidelberg, 2014-08-21) Osuolale, Olayinka; Okoh, Anthony; Sibanda, Timothy; Nongogo, Vuyokazi; Adefisoye, Martins; Nontongana, Nolonwabo
    Vibrios and other enteric pathogens can be found in wastewater effluents of a healthy population. We assessed the prevalence of three non-cholerae vibrios in wastewater effluents of 14 wastewater treatment plants (WWTP) in Chris Hani and Amathole district municipalities in the Eastern Cape Province of South Africa for a period of 12 months. With the exception of WWTP10 where presumptive vibrios were not detected in summer and spring, presumptive vibrios were detected in all seasons in other WWTP effluents. When a sample of 1,000 presumptive Vibrio isolates taken from across all sampling sites were subjected to molecular confirmation for Vibrio, 668 were confirmed to belong to the genus Vibrio, giving a prevalence rate of 66.8 %. Further, molecular characterisation of 300 confirmed Vibrio isolates revealed that 11.6 % (35) were Vibrio parahaemolyticus, 28.6 % (86) were Vibrio fluvialis and 28 % (84) were Vibrio vulnificus while 31.8 % (95) belonged to other Vibrio spp. not assayed for in this study. Antibiogram profiling of the three Vibrio species showed that V. parahaemolyticus was ≥50 % susceptible to 8 of the test antibiotics and ≥50 % resistant to only 5 of the 13 test antibiotics, while V. vulnificus showed a susceptibility profile of ≥50 % to 7 of the test antibiotics and a resistance profile of ≥50 % to 6 of the 13 test antibiotics. V. fluvialis showed ≥50 % resistance to 8 of the 13 antibiotics used while showing ≥50 % susceptibility to only 4 antibiotics used. All three Vibrio species were susceptible to gentamycin, cefuroxime, meropenem and imipenem. Multiple antibiotic resistance patterns were also evident especially against such antibiotics as tetracyclin, polymixin B, penicillin G, sulfamethazole and erythromycin against which all Vibrio species were resistant. These results indicate a significant threat to public health, more so in the Eastern Cape Province of South Africa which is characterised by widespread poverty, with more than a third of the population directly relying on surface water sources for drinking and daily use.