Dzidzo Yirenya-Tawiah

Isolation of Nontuberculous Mycobacteria from the Environment of Ghanian Communities Where Buruli Ulcer Is Endemic.

ABSTRACT This study aimed to isolate nontuberculous mycobacterial species from environmental samples obtained from some selected communities in Ghana. To optimize decontamination, spiked environmental samples were used to evaluate four decontamination solutions and supplemented media, after which the best decontamination solution and media were used for the actual analysis. The isolates obtained were identified on the basis of specific genetic sequences, including heat shock protein 65, IS2404, IS2606, rpoB, and the ketoreductase gene, as needed. Among the methods evaluated, decontamination with 1 M NaOH followed by 5% oxalic acid gave the highest rate of recovery of mycobacteria (50.0%) and the lowest rate of contamination (15.6%). The cultivation medium that supported the highest rate of recovery of mycobacteria was polymyxin B-amphotericin B-nalidixic acid-trimethoprim-azlocillin–supplemented medium (34.4%), followed by isoniazid-supplemented medium (28.1%). Among the 139 samples cultivated in the main analysis, 58 (41.7%) yielded mycobacterial growth, 70 (50.4%) had no growth, and 11 (7.9%) had all inoculated tubes contaminated. A total of 25 different mycobacterial species were identified. Fifteen species (60%) were slowly growing (e.g., Mycobacterium ulcerans, Mycobacterium avium, Mycobacterium mantenii, and Mycobacterium malmoense), and 10 (40%) were rapidly growing (e.g., Mycobacterium chelonae, Mycobacterium fortuitum, and Mycobacterium abscessus). The occurrence of mycobacterial species in the various environmental samples analyzed was as follows: soil, 16 species (43.2%); vegetation, 14 species (38.0%); water, 3 species (8.0%); moss, 2 species (5.4%); snail, 1 species (2.7%); fungi, 1 species (2.7%). This study is the first to report on the isolation of M. ulcerans and other medically relevant nontuberculous mycobacteria from different environmental sources in Ghana. IMPORTANCE Diseases caused by mycobacterial species other than those that cause tuberculosis and leprosy are increasing. Control is difficult because the current understanding of how the organisms are spread and where they live in the environment is limited, although this information is needed to design preventive measures. Growing these organisms from the environment is also difficult, because the culture medium becomes overgrown with other bacteria that also live in the environment, such as in soil and water. We aimed to improve the methods for growing these organisms from environmental sources, such as soil and water samples, for better understanding of important mycobacterial ecology.

Heavy Metal Contamination of Soils around a Hospital Waste Incinerator Bottom Ash Dumps Site

Waste incineration is the main waste management strategy used in treating hospital waste in many developing countries. However, the release of dioxins, POPs, and heavy metals in fly and bottom ash poses environmental and public health concerns. To determine heavy metal (Hg, Pb, Cd, Cr, and Ag) in levels in incinerator bottom ash and soils 100 m around the incinerator bottom ash dump site, ash samples and surrounding soil samples were collected at 20 m, 40 m, 60 m, 80 m, 100 m, and 1,200 m from incinerator. These were analyzed using the absorption spectrophotometer method. The geoaccumulation (I geo) and pollution load indices (PLI) were used to assess the level of heavy metal contamination of surrounding soils. The study revealed high concentrations in mg/kg for, Zn (16417.69), Pb (143.80), Cr (99.30), and Cd (7.54) in bottom ash and these were above allowable limits for disposal in landfill. The study also found soils within 60 m radius of the incinerator to be polluted with the metals. It is recommended that health care waste managers be educated on the implication of improper management of incinerator bottom ash and regulators monitor hospital waste incinerator sites.

Environmental and Behavioral Drivers of Buruli Ulcer Disease in Selected Communities Along the Densu River Basin of Ghana: A Case-Control Study

The exact route of transmission of Mycobacterium ulcerans (MU) (causative agent of Buruli ulcer [BU]), risk factors, and reservoir hosts are not clearly known, although it has been identified as an environmental pathogen. This study assessed potential environmental and behavioral risk factors that influence BU infections. We conducted a case-control study where cases were matched by their demographic characteristics and place of residence. A structured questionnaire was administered to solicit information on the environmental and behavioral factors of participants that may expose them to infection. A total of 176 cases and 176 controls were enrolled into the study. Multivariate conditional logistic regression analysis identified farming in swampy areas (odds ratio [OR] = 4.10, 95% confidence interval [CI] = 3.82–7.18), farming while wearing short clothing (OR = 1,734.1, 95% CI = 68.1–44,120.9), insect bite (OR = 988.3, 95% CI = 31.4–31,115.6), and application of leaves on wounds (OR = 6.23, 95% CI = 4.74–18.11) as potential risk factors. Farming in long clothing (OR = 0.000, 95% CI = 0.00–0.14), washing wound with water and soap (OR = 0.37, 95% CI = 0.29–0.98), and application of adhesive bandage on wounds (OR = 0.31, 95% CI = 0.15–0.82) were found to be protective against BU infection. In the absence of the exact MU transmission mechanisms, education of public in BU-endemic zones on the use of protective clothing during farming activities to limit exposure of the skin and proper wound care management would be essential in the fight against BU.

Bacteriological quality of the wastewater used for irrigation at the vegetable farms in Korle-bu Teaching Hospital, Accra Metropolis, Ghana

Many developing countries, including Ghana, are water stressed. As such, farmers, particularly those in urban areas, have adopted the use of wastewater for irrigation. This study evaluated the bacteriological water quality of the wastewater used for irrigation in the vegetable farms at Korle-Bu Teaching Hospital (KBTH), Accra Metropolis, Ghana. In all, 40 wastewater samples were collected and analysed bacteriologically using the total aerobic plate count method. The isolated bacteria were identified biochemically using Bergey’s manual for determinative bacteriology. Mean total bacterial colony count values in the range of 2.75–4.44 × 105 CFU/100 mL were isolated which far exceeds values of 1 × 103/100 mL recommended by the World Health Organization (WHO) for unrestricted irrigation of crops likely to be eaten raw. Enterobacter cloacae (51.4%), Klebsiella sp. (24.1%), Pseudomonas aeruginosa (11.3%), Salmonella typhi (10.6%), Escherichia coli (2.2%) and Proteus sp. (0.4%) were the predominant bacteria isolated. Growers should use treated wastewater for farming while processors and consumers should minimize contamination risks of produce from the vegetable farms/garden to the plate.

Heavy metals concentration and distribution in soils and vegetation at Korle Lagoon area in Accra, Ghana

Abstract The call for reclamation of land around Korle Lagoon in Accra, Ghana, where burning of e-waste and cultivation of vegetables takes place, makes risk assessment of heavy metal contaminations important. This study aimed at evaluating the levels and risk of heavy metal contamination in soils and vegetation around the Korle lagoon area in Accra. Geoaccumulation index, enrichment factor and pollution load index were determined to assess the risk of contamination. The levels and distribution of nine heavy metals (Pb, Hg, Cd, As, Zn, Sn, Ni, Cu and Cr) in soil (0–20 cm) and common vegetation (Panicum maximum, Imperata cylindrica, Lactuca sativa and Hibiscus sabdariffa) from the area using Atomic Absorption Spectrometer (AAS) were assessed. The area was divided into five sites, namely; the e-waste site (S1), gardens area (S2), recreational area (S3), reclaimed area (S4) estuary (S5) and the control (S6) which was about 700 m away. Soil analysis showed that the concentration of Pb (184.44 mg/kg), Cd (103.66 mg/kg), Cu (202.99 mg/kg), Ni (72.00 mg/kg) and Sn (705.32 mg/kg) at S1 exceeded their WHO/FAO thresholds for agricultural soils. Concentrations of heavy metals in soils from the e-waste site were significantly different (p < 0.01) from the other sites. High accumulations of heavy metals were also observed in the plants samples collected from the study sites, with the concentrations of Cu, Pb, Ni and Cd exceeding their acceptable limits. Laws against open burning of e-waste should be enforced and animals should be restricted from grazing on the forage.