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Iwu-Jaja C, Ndlovu NL, Rachida S, Yousif M, Taukobong S, Macheke M, Mhlanga L, van Schalkwyk C, Pulliam JRC, Moultrie T, le Roux W, Schaefer L, Pocock G, Coetzee LZ, Mans J, Bux F, Pillay L, de Villiers D, du Toit AP, Jambo D, Gomba A, Groenink S, Madgewick N, van der Walt M, Mutshembele A, Berkowitz N, Suchard M, McCarthy K. The role of wastewater-based epidemiology for SARS-CoV-2 in developing countries: Cumulative evidence from South Africa supports sentinel site surveillance to guide public health decision-making. Sci Total Environ 2023; 903:165817. [PMID: 37506905 DOI: 10.1016/j.scitotenv.2023.165817] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 07/30/2023]
Abstract
The uptake of wastewater-based epidemiology (WBE) for SARS-CoV-2 as a complementary tool for monitoring population-level epidemiological features of the COVID-19 pandemic in low-and-middle-income countries (LMICs) is low. We report on the findings from the South African SARS-CoV-2 WBE surveillance network and make recommendations regarding the implementation of WBE in LMICs. Eight laboratories quantified influent wastewater collected from 87 wastewater treatment plants in all nine South African provinces from 01 June 2021 to 31 May 2022 inclusive, during the 3rd and 4th waves of COVID-19. Correlation and regression analyses between wastewater levels of SARS-CoV-2 and district laboratory-confirmed caseloads were conducted. The sensitivity and specificity of novel 'rules' based on WBE data to predict an epidemic wave were determined. Amongst 2158 wastewater samples, 543/648 (85 %) samples taken during a wave tested positive for SARS-CoV-2 compared with 842 positive tests from 1512 (55 %) samples taken during the interwave period. Overall, the regression-co-efficient was 0,66 (95 % confidence interval = 0,6-0,72, R2 = 0.59), ranging from 0.14 to 0.87 by testing laboratory. Early warning of the 4th wave of SARS-CoV-2 in Gauteng Province in November-December 2021 was demonstrated. A 50 % increase in log copies of SARS-CoV-2 compared with a rolling mean over the previous five weeks was the most sensitive predictive rule (58 %) to predict a new wave. Our findings support investment in WBE for SARS-CoV-2 surveillance in LMICs as an early warning tool. Standardising test methodology is necessary due to varying correlation strengths across laboratories and redundancy across testing plants. A sentinel site model can be used for surveillance networks without affecting WBE finding for decision-making. Further research is needed to identify optimal test frequency and the need for normalisation to population size to identify predictive and interpretive rules to support early warning and public health action.
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Affiliation(s)
- Chinwe Iwu-Jaja
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, South Africa.
| | - Nkosenhle Lindo Ndlovu
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, South Africa.
| | - Said Rachida
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, South Africa
| | - Mukhlid Yousif
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, South Africa; School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Setshaba Taukobong
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, South Africa
| | - Mokgaetji Macheke
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, South Africa
| | - Laurette Mhlanga
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, South Africa
| | - Cari van Schalkwyk
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, South Africa
| | - Juliet R C Pulliam
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, South Africa
| | - Tom Moultrie
- Centre for Actuarial Research, University of Cape Town, South Africa
| | - Wouter le Roux
- Water Centre, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Lisa Schaefer
- Water Centre, Council for Scientific and Industrial Research, Pretoria, South Africa
| | | | | | - Janet Mans
- Department of Medical Virology, University of Pretoria, Pretoria, South Africa
| | - Faizal Bux
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, South Africa
| | - Leanne Pillay
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, South Africa
| | | | - A P du Toit
- Lumegen Laboratories (Pty) Ltd, Potchefstroom, South Africa
| | - Don Jambo
- National Institute for Occupational Health, South Africa
| | | | | | | | | | | | | | - Melinda Suchard
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, South Africa; School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Kerrigan McCarthy
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, South Africa; School of Pathology, University of the Witwatersrand, Johannesburg, South Africa; School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
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Poopedi E, Singh T, Gomba A. Potential Exposure to Respiratory and Enteric Bacterial Pathogens among Wastewater Treatment Plant Workers, South Africa. Int J Environ Res Public Health 2023; 20:4338. [PMID: 36901349 PMCID: PMC10002314 DOI: 10.3390/ijerph20054338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/23/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Wastewater handling has been associated with an increased risk of developing adverse health effects, including respiratory and gastrointestinal illnesses. However, there is a paucity of information in the literature, and occupational health risks are not well quantified. Grab influent samples were analysed using Illumina Miseq 16S amplicon sequencing to assess potential worker exposure to bacterial pathogens occurring in five municipal wastewater treatment plants (WWTPs). The most predominant phyla were Bacteroidota, Campilobacterota, Proteobacteria, Firmicutes, and Desulfobacterota, accounting for 85.4% of the total bacterial community. Taxonomic analysis showed a relatively low diversity of bacterial composition of the predominant genera across all WWTPs, indicating a high degree of bacterial community stability in the influent source. Pathogenic bacterial genera of human health concern included Mycobacterium, Coxiella, Escherichia/Shigella, Arcobacter, Acinetobacter, Streptococcus, Treponema, and Aeromonas. Furthermore, WHO-listed inherently resistant opportunistic bacterial genera were identified. These results suggest that WWTP workers may be occupationally exposed to several bacterial genera classified as hazardous biological agents for humans. Therefore, there is a need for comprehensive risk assessments to ascertain the actual risks and health outcomes among WWTP workers and inform effective intervention strategies to reduce worker exposure.
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Affiliation(s)
- Evida Poopedi
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg 2000, South Africa
- Department of Clinical Microbiology and Infectious Diseases, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Tanusha Singh
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg 2000, South Africa
- Department of Clinical Microbiology and Infectious Diseases, University of the Witwatersrand, Johannesburg 2050, South Africa
- Department of Environmental Health, University of Johannesburg, Doornfontein 2028, South Africa
| | - Annancietar Gomba
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg 2000, South Africa
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Seetswane E, Loeto D, Muzila M, Tshekiso K, Gomba A, Baruti K, Jongman M. Phenotypic and genotypic profiling reveals a high prevalence of methicillin-resistant Staphylococcus aureus isolated from hospitals, houseflies and adjacent informal food retailers in Botswana. Microbiology (Reading) 2022; 168. [PMID: 36287593 DOI: 10.1099/mic.0.001213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The increasing occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in the environment, food and healthcare systems is a global public health concern. MRSA is reported to cause food poisoning, osteomyelitis and pyogenic infections of the skin, and consequently has been categorized as a high-priority pathogen by the World Health Organization. Here, we determined the presence of MRSA in clinical (n=56), food (n=150) and housefly samples (n=970) collected from two hospitals in Botswana. Characterization based on phenotypic (antimicrobial resistance, biofilm production) and genotypic (antimicrobial resistance genes and integrons) profiles were performed on all isolates. Of the total samples tested, 64 were positive for MRSA following conventional culture methods and PCR amplification of the mecA and mecC genes for confirmation of presumptive MRSA isolates. The confirmed isolates included 71 % (95 % CI 83.2-59.6) from clinical, 9 % (95 % CI 14--4.8) from food, and 1 % (95 % CI 1.6-0.4) collected from housefly samples. In total 89 % (n=57) isolates in the current study showed a multidrug resistance phenotype, among these, resistance to β-lactams and glycoside antibiotic classes were predominant. Genotypic characterization showed the domination of the blatem gene (95 %) followed by fox (63 %) and tetO (19 %) whilst vanA was only reported in 13 % of the isolates. Integrons were detected in 50 % (32/64) of the total MRSA isolates, and we report a high prevalence of etd gene, detected in 67 % (43/64) of the isolates followed by eta 38 % (24/64) whilst tsst-1 (3%) was the least detected genetic determinant. The genes etb and PVL were not detected in a ll the tested MRSA isolates. We provide the first report on the prevalence of MRSA isolated from the clinical-food-vector nexus harbouring biofilm and blatem genes, and antibiotic resistance profiles in Botswana. These results are significant for risk-assessment analysis and the development of improved MRSA infection prevention and control strategies.
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Affiliation(s)
- Eunicah Seetswane
- Department of Biological Sciences, Faculty of Science, University of Botswana, Private Bag 0022, Gaborone, Botswana
| | - Daniel Loeto
- Department of Biological Sciences, Faculty of Science, University of Botswana, Private Bag 0022, Gaborone, Botswana
| | - Mbaki Muzila
- Department of Biological Sciences, Faculty of Science, University of Botswana, Private Bag 0022, Gaborone, Botswana
| | - Kgomotso Tshekiso
- Department of Biological Sciences, Faculty of Science, University of Botswana, Private Bag 0022, Gaborone, Botswana
| | - Annancietar Gomba
- National Health Laboratory Services, National Institute of Occupational Health, Johannesburg, South Africa
| | - Kabo Baruti
- Department of Biological Sciences, Faculty of Science, University of Botswana, Private Bag 0022, Gaborone, Botswana.,Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana
| | - Mosimanegape Jongman
- Department of Biological Sciences, Faculty of Science, University of Botswana, Private Bag 0022, Gaborone, Botswana
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Poopedi E, Kwenda S, Singh T, Gomba A. Potential occupational exposure to respiratory and gastrointestinal bacterial pathogens at wastewater treatment plants, South Africa. Saf Health Work 2022. [DOI: 10.1016/j.shaw.2021.12.1377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Jongman M, Carmichael P, Loeto D, Gomba A. Advances in the use of biocontrol applications in preharvest and postharvest environments: A food safety milestone. J Food Saf 2021. [DOI: 10.1111/jfs.12957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Patricia Carmichael
- Department of Agricultural Research and Specialists Services Malkerns Eswatini
| | - Daniel Loeto
- Department of Biological Sciences University of Botswana Gaborone Botswana
| | - Annancietar Gomba
- National Institute for Occupational Health National Health Laboratory Service Johannesburg South Africa
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Gomba A, Chidamba L, Korsten L. Viable microbial loads on citrus carpoplane during packhouse processing and survival of foodborne pathogens in reconstituted postharvest fungicides. J Food Saf 2017. [DOI: 10.1111/jfs.12357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- A. Gomba
- Department of Plant and Soil Sciences; University of Pretoria; Hatfield 0028 South Africa
| | - L. Chidamba
- Department of Plant and Soil Sciences; University of Pretoria; Hatfield 0028 South Africa
| | - L. Korsten
- Department of Plant and Soil Sciences; University of Pretoria; Hatfield 0028 South Africa
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Gomba A, Chidamba L, Korsten L. Effect of postharvest practices including degreening on citrus carpoplane microbial biomes. J Appl Microbiol 2017; 122:1057-1070. [PMID: 28052466 DOI: 10.1111/jam.13396] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/23/2016] [Accepted: 12/13/2016] [Indexed: 01/04/2023]
Abstract
AIMS To investigate the effect of commercial citrus packhouse processing steps on the fruit surface microbiome of Clementines and Palmer navel oranges. METHODS AND RESULTS Viable bacteria, yeast and fungi counts, and the pyrosequencing analysis of the 16S rRNA and ITS were used to evaluate the community structure and population dynamics of phylloepiphytic bacteria and fungi associated with commercial postharvest processing. Drenching significantly reduced microbial counts in all cases except for yeasts on navels, while the extent of degreening effects varied between the citrus varieties. Pyrosequencing analysis showed a total of 4409 bacteria and 5792 fungi nonchimeric unique sequences with an average of 1102 bacteria and 1448 fungi reads per sample. Dominant phyla on the citrus carpoplane were Proteobacteria (53·5%), Actinobacteria (19·9%), Bacteroidetes (5·6%) and Deinococcus-Thermus (5·4%) for bacteria and Ascomycota (80·5%) and Basidiomycota (9·8%) for fungi. Beginning with freshly harvested fruit fungal diversity declined significantly after drenching, but had little effect on bacteria and populations recovered during degreening treatments, including those for Penicillium sp. CONCLUSION Packhouse processing greatly influences microbial communities on the citrus carpoplane. SIGNIFICANCE AND IMPACT OF THE STUDY A broad orange biome was described with pyrosequencing and gave insight into the likely survival and persistence of pathogens, especially as they may affect the quality and safety of the packed product. A close examination of the microbiota of fruit and the impact of intervention strategies on the ecological balance may provide a more durable approach to reduce losses and spoilage.
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Affiliation(s)
- A Gomba
- Department of Plant and Soil Sciences, University of Pretoria, Hatfield, South Africa
| | - L Chidamba
- Department of Plant and Soil Sciences, University of Pretoria, Hatfield, South Africa
| | - L Korsten
- Department of Plant and Soil Sciences, University of Pretoria, Hatfield, South Africa
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Gomba A, Chidamba L, Korsten L. Prevalence and serovar diversity of Salmonella spp. in primary horticultural fruit production environments. Food Control 2016. [DOI: 10.1016/j.foodcont.2016.04.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Gomba A, Chidamba L, Korsten L. Antimicrobial Resistance Profiles ofSalmonellaspp. from Agricultural Environments in Fruit Production Systems. Foodborne Pathog Dis 2016; 13:495-501. [DOI: 10.1089/fpd.2016.2120] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Annancietar Gomba
- Department of Plant Science, Institute for Food Nutrition and Well-Being, University of Pretoria, Hatfield, South Africa
| | - Lizyben Chidamba
- Department of Plant Science, Institute for Food Nutrition and Well-Being, University of Pretoria, Hatfield, South Africa
| | - Lise Korsten
- Department of Plant Science, Institute for Food Nutrition and Well-Being, University of Pretoria, Hatfield, South Africa
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