Research Articles
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A research article reports the results of original research, assesses its contribution to the body of knowledge in a given area, and is published in a peer-reviewed scholarly journal. The faculty publications through published and on-going articles/researches are captured in this community
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Item Genetic Analysis of TB Susceptibility Variants in Ghana Reveals Candidate Protective Loci in SORBS2 and SCL11A1 Genes(Frontier, 2022) Asante-Poku, A.; Morgan, P.; Osei-Wusu, S.; Aboagye, S.Y.; Asare, P.; Otchere, I.D.; Adadey, S.W.; Mnika, K.; Esoh, K.; Mawuta, K.H.; Arthur, N.; Forson, A.; Mazandu, G.K.; Wonkam, A.; Yeboah-Manu, D.Despite advancements made toward diagnostics, tuberculosis caused by Mycobacterium africanum (Maf) and Mycobacterium tuberculosis sensu stricto (Mtbss) remains a major public health issue. Human host factors are key players in tuberculosis (TB) outcomes and treatment. Research is required to probe the interplay between host and bacterial genomes. Here, we explored the association between selected human/host genomic variants and TB disease in Ghana. Paired host genotype datum and infecting bacterial isolate information were analyzed for associations using a multinomial logistic regression. Mycobacterium tuberculosis complex (MTBC) isolates were obtained from 191 TB patients and genotyped into different phylogenetic lineages by standard methods. Two hundred and thirty-five (235) nondisease participants were used as healthy controls. A selection of 29 SNPs from TB disease-associated genes with high frequency among African populations was assayed using a TaqMan® SNP Genotyping Assay and iPLEX Gold Sequenom Mass Genotyping Array. Using 26 high-quality SNPs across 326 case-control samples in an association analysis, we found a protective variant, rs955263, in the SORBS2 gene against both Maf and Mtb infections (PBH = 0.05; OR = 0.33; 95% CI = 0.32–0.34). A relatively uncommon variant, rs17235409 in the SLC11A1 gene was observed with an even stronger protective effect against Mtb infection (MAF = 0.06; PBH = 0.04; OR = 0.05; 95% CI = 0.04–0.05). These findings suggest SLC11A1 and SORBS2 as a potential protective gene of substantial interest for TB, which is an important pathogen in West Africa, and highlight the need for in-depth host-pathogen studies in West Africa.Item Zoonotic tuberculosis—a call for an open One Health debate(Lancet Infectious Diseases, 2020-02-23) Yeboah-Manu, D.; Zumla, A.; Michel, A.L.; Azhar, E.I.; Torrelles, J.B.; Cadmus, S.II.; Kendall, S.L.; Chakaya, J.M.; Marais, B.; kock, R.Tuberculosis is caused by bacteria of the Mycobacterium tuberculosis complex (MTBC) and affects both human and animal populations. Animal-adapted MTBC threatens the wellbeing of humans, animals, and their livelihoods. The 2019 WHO annual tuberculosis report1 estimated that there were 143 000 new human cases of zoonotic tuberculosis with 12 300 deaths caused by Mycobacterium bovis globally in 2018. Prevalence estimates of zoonotic tuberculosis are inaccurate, however, because routine laboratory tests cannot differentiate between infections caused by the humanadapted and animal-adapted species of MTBC, including newer members such as Mycobacterium orygis.2 Thus, the true effect of zoonotic tuberculosis on the human tuberculosis epidemic remains unclear. Accurate disease differentiation is also important given that M bovis isuniversally resistant to pyrazinamide, a key first-line tuberculosis drug.Item Commemorating World TB Day 2020: “IT’S TIME” — It’s time to End the Global TB Epidemic(International Journal of Infectious Diseases, 2020-03) Yeboah-Manu, D.; Tiberi, S.; Migliori, G.B.; Chakaya, J.M.; Kaesava, T.; Abri, S.S.; Wejse, C.; Goletti, D.; Kapata, N.; Sotgiu, G.; Bomanji, J.; Zellweger, J-P.; Hasan, R.World TB Day falls on March 24th each year, and it commemorates the day in 1882 when Dr Robert Koch announced that he had discovered the microbial cause of tuberculosis, Mycobacterium tuberculosis (WHO, 2020a,b,c). At the time of Professor Koch’s announcement in Berlin, TB was an endemic in Europe and the Americas, and caused the death of one in every seven people (Wallstedt and Maeurer, 2015). Koch’s discovery opened the way towards diagnosing, treating and curing patients with TB. One hundred and twenty eight years later, according to the WHO Annual TB Report, an estimated 10 million people fell ill with TB and 1.5 million died of it. Tuberculosis remains the top infectious disease killer worldwide (WHO, 2019).Item Microbiological Quality of “Khebab” Consumed in the Accra Metropolis(Ghana Medical Journal, 2005-06) Agbodaze, D.; Nmai, P.N.A.; Robertson, F.C.; Yeboah-Manu, D.; Owusu-Darko, K.; Addo, K.K.The study was carried out in 2003 to evaluate the microbial load in “khebab”, meat products from pork, and beef, which are vended in most of the streets and some public drinking places, either with alcoholic or non-alcoholic drinks. Osu (Alata), Nima-Kotobabi and Central Accra (Adabraka – very close to the main lorry station), all in the Accra Metropolis, were selected for the investigation. The main reason for the selection of these sites was based on the population density as well as patronage for the khebab. Our main inter-est for this investigation was to assess the micro-bial load in khebab as far as enteric pathogen and other pathogenic micro-organisms reported earlier in the raw meat are concerned. Thirty samples of khebab were bought from these sampling points. Results obtained from samples at Osu recorded mean total plate count (TPC) of 5.02, Accra Cen-tral samples had TPC of 4.08 and those from Nima had TPC of 4.80 log10 colony-forming units (cfu) per gram of khebab. Samples from Accra Central recorded the highest mean coliform count (5.12) whist samples bought from Osu and Nima re-corded 4.41 and 3.70 log10 cfu/g respectively. Ac-cra Central samples again recorded the highest faecal coliforms (4.4 log10 cfu/g) as compared to 3.98 and 3.80 log10 cfu/g for samples bought from Osu and Nima respectively. Salmonella ssp were not isolated from the samples bought at the three sampling sites. Khebab samples from sites were contaminated with E. coli, other gram-negative bacteria and Staphylococcus species, whose viru-lence factor(s) are yet to be determined. The faecal coliforms enumerated could originate from either humans or the animals slaughtered for the khebab. Staphylococcus species could originate from the vendors. Vendors have to be educated on hygienic practices which could help reduce risks of food-borne infection. Skin disinfection can be done by a thorough wash. Vendors could also be educated to stop selling their products to customers once they have bouts of diarrhoea, vomiting and “fever”. Washing of their hands with soap and water before serving their customers could also help reduce the risk of food-borne infection from eating their products.Item Diagnosis of Tuberculosis in Ghana: The Role of Laboratory Training(Ghana Medical Journal, 2010-03) Addo, K.K.; Yeboah-Manu, D.; Dan-Dzide, M.; Owusu-Darko, K.; Caulley, P.; Mensah, G.I.; Minamikawa, M.; Lienhardt, C.; Bonsu, F.A.; Ofori-Adjei, D.Objectives: The laboratory is considered the cornerstone of tuberculosis (TB) control programme. International review of Ghana’s programme in the late nineties identified the laboratory services as the weakest component. Sputum smear microscopy (SSM) being the main method of diagnosing pulmonary TB in Ghana, the training objectives were to: (i) strengthen the knowledge and skills of laboratory personnel on SSM (ii) impart necessary techniques in biosafety and (iii) introduce a Quality Assurance (QA) system in order to strengthen SSM services. Methods: Personnel were selected for training during a nationwide situation analysis of SSM centres in 2000/2001. Four training sessions on SSM/QA were held between 2001/2004. Results: A total of 80 personnel were trained: 10 regional TB coordinators and 70 laboratory personnel. The participants upon return to their respective regions also organized training within their districts. This approach resulted in another 100 district TB coordinators and 200 laboratory personnel being trained. Improvement in smear preparation, staining and reading ability of the participants were observed during the post-test and subsequent visit to their respective laboratories. The training has led to strengthening of TB laboratory services in the country and has contributed to increase in case detection from 10,745 in 2000 to 11,827 in 2004 and 14,022 in 2008. It was observed during the post-training follow-up and quarterly supervision visits that morale of the personnel was high. Conclusion: Continuous training and re-training of laboratory personnel on SSM and QA at regular intervals do play an important role for effective and efficient TB control programme.Item OMNIgene SPUTUM: A good transport and decontaminating reagent for tuberculosis testing(International Journal of Mycobacteriology, 2018-07) Asandem, D.A.; Asante-Poku, A.; Asare, P.; Aboagye, S.Y.; Stephen, O.W.; Danso, E.; Klevor, P.M.; Hayibor, K.M.; Yeboah-Manu, D.Background: Sputum culture is limited to centralized facilities. Thus, samples require transportation from peripheral laboratories to these facilities, compromising specimen quality since it is difficult to maintain cold chain. We evaluated OMNIgene SPUTUM Reagent (OMS) for transporting sputum samples for tuberculosis (TB) testing. The study was carried out at Noguchi Memorial Institute for Medical Research using sputa from Korle Bu Teaching Hospital and La General Hospital in Ghana. Methods: In a laboratory-based controlled experiment (CE), sputum contaminants were determined on blood agar before treatment with OMS and N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH). TB testing included smear microscopy, culture, and Xpert MTB/RIF. Afterward, two peripheral laboratories were trained to transport sputum samples with OMS without cold chain. Positivity, negativity, and contamination rates were compared between both methods using Chi-square and Fisher's exact tests. Cohen's Kappa was also used to determine agreements. Results: Among 104 sputum samples analyzed in the CE, 93 (89.4%) had bacterial growth on blood agar before decontamination, while 6 (5.8%) and 5 (4.8%) contaminated after NALC-NaOH and OMS treatment, respectively. Contamination was high with NALC-NaOH (12.8%) than OMS (4.3%) on Lowenstein-Jensen media (P < 0.001), but mycobacterial positivity was comparable: NALC-NaOH of 74.5% and OMS of 78.7%. Smear positivity after NALC-NaOH treatment was 89.4% and OMS was 75.9% (P = 0.491). All except one of the samples tested positive by Xpert MTB/RIF after both treatment. Sixteen samples were evaluated in the field experiment and 81.3% yielded positive culture, and no contamination on LJ was observed. Conclusion: Our findings indicate that OMS works well as a transport and decontaminating reagent of samples for TB testing.Item Isolation of nontuberculous mycobacteria from the environment of ghanian communities where buruli ulcer is endemic(American Society for Microbiology, 2016) Aboagye, S.Y.; Danso, E.; Ampah, K.A.; Nakobu, Z.; Asare, P.; Otchere, I.D.; Röltgen, K.; Yirenya-Tawiah, D.; Yeboah-Manu, D.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 1MNaOH 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 acidtrimethoprim- 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. © 2016, American Society for Microbiology.Item Antimycobacterial and cytotoxic activity of selected medicinal plant extracts(Journal of Ethnopharmacology, 2016-04) Nguta, J.M.; Appiah-Opong, R.; Nyarko, A.K.; Yeboah-Manu, D.; Addo, P.G.A.; Otchere, I.; Kissi-Twum, A.Ethnopharmacological relevance Tuberculosis (TB) caused by Mycobacterium tuberculosis remains an ongoing threat to human health. Several medicinal plants are used traditionally to treat tuberculosis in Ghana. The current study was designed to investigate the antimycobacterial activity and cytotoxicity of crude extracts from five selected medicinal plants. Material and methods The microplate alamar blue assay (MABA) was used for antimycobacterial studies while the CellTiter 96® AQueous Assay, which is composed of solutions of a novel tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; MTS] and an electron coupling reagent (phenazine methosulfate) PMS, was used for cytotoxic studies. Correlation coefficients were used to compare the activity of crude extracts against nonpathogenic strains and the pathogenic Mycobacterium tuberculosis subsp.tuberculosis. Results Results of the MIC determinations indicated that all the crude extracts were active on all the three tested mycobacterial strains. Minimum inhibitory concentration values as low as 156.3 μg/mL against M. tuberculosis; Strain H37Ra (ATCC® 25,177™) were recorded from the leaves of Solanum torvum Sw. (Solanaceae). Cytotoxicity of the extracts varied, and the leaves from S. torvum had the most promising selectivity index. Activity against M. tuberculosis; Strain H37Ra was the best predictor of activity against pathogenic Mycobacterium tuberculosis subsp.tuberculosis (correlation coefficient=0.8). Conclusion The overall results of the present study provide supportive data on the use of some medicinal plants for tuberculosis treatment. The leaves of Solanum torvum are a potential source of anti-TB natural products and deserve further investigations to develop novel anti-TB agents against sensitive and drug resistant strains of M. tuberculosis. © 2016 The Authors.Item Significant under expression of the DosR regulon in M. tuberculosis complex lineage 6 in sputum(Tuberculosis, 2017-05) Ofori-Anyinam, B.; Dolganov, G.; Van, T.; Davis, J.L.; Walter, N.D.; Garcia, B.J.; Voskuil, M.; Fissette, K.; Diels, M.; Driesen, M.; Meehan, C.J.; Yeboah-Manu, D.; Coscolla, M.; Gagneux, S.; Antonio, M.; Schoolnik, G.; Gehre, F.; de Jong, B.C.Mycobacterium africanum lineage (L) 6 is an important pathogen in West Africa, causing up to 40% of pulmonary tuberculosis (TB). The biology underlying the clinical differences between M. africanum and M. tuberculosis sensu stricto remains poorly understood. We performed ex vivo expression of 2179 genes of the most geographically dispersed cause of human TB, M. tuberculosis L4 and the geographically restricted, M. africanum L6 directly from sputa of 11 HIV-negative TB patients from The Gambia who had not started treatment. The DosR regulon was the most significantly decreased category in L6 relative to L4. Further, we identified nonsynonymous mutations in major DosR regulon genes of 44 L6 genomes of TB patients from The Gambia and Ghana. Using Lebek's test, we assessed differences in oxygen requirements for growth. L4 grew only at the aerobic surface while L6 grew throughout the medium. In the host, the DosR regulon is critical for M. tuberculosis in adaptation to oxygen limitation. However, M. africanum L6 appears to have adapted to growth under hypoxic conditions or to different biological niches. The observed under expression of DosR in L6 fits with the genomic changes in DosR genes, microaerobic growth and the association with extrapulmonary disease. © 2017 The AuthorsItem Laboratory confirmation of Buruli ulcer cases in Ghana, 2008-2016(PLoS Neglected Tropical Diseases, 2018-06) Yeboah-Manu, D.; Aboagye, S.Y.; Asare, P.; Asante-Poku, A.; Ampah, K.; Danso, E.; Owusu-Mireku, E.; Nakobu, Z.; Ampadu, E.Background: Buruli ulcer (BU), a necrotizing skin infection caused by Mycobacterium ulcerans is the third most important mycobacterial disease globally after tuberculosis and leprosy in immune competent individuals. This study reports on the retrospective analyses of microbiologically confirmed Buruli ulcer (BU) cases in seventy-five health facilities in Ghana. Method/Principal findings: Pathological samples were collected from BU lesions and transported either through courier services or by car directly to the laboratory. Samples were processed and analysed by IS2404 PCR, culture and Ziehl-Neelsen staining for detection of acid-fast bacilli. From 2008 to 2016, we analysed by PCR, 2,287 samples of 2,203 cases from seventy-five health facilities in seven regions of Ghana (Ashanti, Brong Ahafo, Central, Eastern, Greater Accra, Northern and Volta). The mean annual positivity rate was 46.2% and ranged between 14.6% and 76.2%. The yearly positivity rates from 2008 to 2016 were 52.3%, 76.2%, 56.7%, 53.8%, 41.2%, 41.5%, 22.9%, 28.5% and 14.6% respectively. Of the 1,020 confirmed cases, the ratio of female to male was 518 and 502 respectively. Patients who were 15 years of age and below accounted for 39.8% of all cases. The median age was 20 years (IQR = 10–43). Ulcerative lesions were 69.2%, nodule (9.6%), plaque (2.9%), oedema (2.5%), osteomyelitis (1.1%), ulcer/oedema (9.5%) and ulcer/plaque (5.2%). Lesions frequently occurred on the lower limbs (57%) followed by the upper limbs (38%), the neck and head (3%) and the least found on the abdomen (2%). Conclusions/Significance: Our findings show a decline in microbiological confirmed rates over the years and therefore call for intensive education on case recognition to prevent over-diagnosis as BU cases decline. © 2018 Yeboah-Manu et al. http://creativecommons.org/licenses/by/4.0/