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 Buruli Ulcer: a Review of the Current Knowledge(Current Tropical Medicine Reports, 2018-12) Yotsu, R.R.; Suzuki, K.; Simmonds, R.E.; Bedimo, R.; Ablordey, A.; Yeboah-Manu, D.; Phillips, R.; Asiedu, K.Purpose of the Review Buruli ulcer (BU) is a necrotizing and disabling cutaneous disease caused by Mycobacterium ulcerans, one of the skin-related neglected tropical diseases (skin NTDs). This article aims to review the current knowledge of this disease and challenges ahead. Recent Findings Around 60,000 cases of BU have been reported from over 33 countries between 2002 and 2017. Encouraging findings for development of point-of-care tests for BU are being made, and its treatment is currently in the transition period from rifampicin plus streptomycin (injection) to all-oral regimen. A major recent advance in our understanding of its pathogenesis has been agreement on the mechanism of action of the major virulence toxin mycolactone in host cells, targeting the Sec61 translocon during a major step in protein biogenesis. Summary BU is distributed mainly in West Africa, but cases are also found in other parts of the world. We may be underestimating its true disease burden, due to the limited awareness of this disease. More awareness and more understanding of BU will surely contribute in enhancing our fight against this skin NTD.Item Possible healthcare-associated transmission as a cause of secondary infection and population structure of Staphylococcus aureus isolates from two wound treatment centres in Ghana(New Microbes and New Infections, 2016-07) Kpeli, G.; Darko Otchere, I.; Lamelas, A.; Buultjens, A.L.; Bulach, D.; Baines, S.L.; Seemann, T.; Giulieri, S.; Nakobu, Z.; Aboagye, S.Y.; Owusu-Mireku, E.; Pluschke, G.; Stinear, T.P.; Yeboah-Manu, D.We have previously shown that secondary infections of Buruli ulcer wounds were frequently caused by Staphylococcus aureus. To gain understanding into possible routes of secondary infection, we characterized S. aureus isolates from patient lesions and surrounding environments across two Ghanaian health centres. One hundred and one S. aureus isolates were isolated from wounds (n = 93, 92.1%) and the hospital environment (n = 8, 7.9%) and characterized by the spa gene, mecA and the Panton–Valentine leucocidin toxin followed by spa sequencing and whole genome sequencing of a subset of 49 isolates. Spa typing and sequencing of the spa gene from 91 isolates identified 29 different spa types with t355 (ST152), t186 (ST88), and t346 dominating. Although many distinct strains were isolated from both health centres, genotype clustering was identified within centres. In addition, we identified a cluster consisting of isolates from a healthcare worker, patients dressed that same day and forceps used for dressing, pointing to possible healthcare-associated transmission. These clusters were confirmed by phylogenomic analysis. Twenty-four (22.8%) isolates were identified as methicillin-resistant S. aureus and lukFS genes encoding Panton–Valentine leucocidin were identified in 67 (63.8%) of the isolates. Phenotype screening showed widespread resistance to tetracycline, erythromycin, rifampicin, amikacin and streptomycin. Genomics confirmed the widespread presence of antibiotic resistance genes to β-lactams, chloramphenicol, trimethoprim, quinolone, streptomycin and tetracycline. Our findings indicate that the healthcare environment probably contributes to the superinfection of Buruli ulcer wounds and calls for improved training in wound management and infection control techniques. © 2016 The Author(s)Item 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/Item Primary cultivation: Factors affecting contamination and Mycobacterium ulcerans growth after long turnover time of clinical specimens(BMC Infectious Diseases, 2014-11) Bratschi, M.W.; Bolz, M.; Grize, L.; Kerber, S.; Minyem, J.C.; Um Boock, A.; Yeboah-Manu, D.; Ruf, M.-T.; Pluschke, G.Background: While cultivation of pathogens represents a foundational diagnostic approach in the study of infectious diseases, its value for the confirmation of clinical diagnosis of Buruli ulcer is limited by the fact that colonies of Mycobacterium ulcerans appear only after about eight weeks of incubation at 30°C. However, for molecular epidemiological and drug sensitivity studies, primary isolation of M. ulcerans remains an essential tool. Since for most of the remote Buruli ulcer endemic regions of Africa cultivation laboratories are not easily accessible, samples from lesions often have to be stored for extended periods of time prior to processing. The objective of the current study therefore was to determine which transport medium, decontamination method or other factors decrease the contamination rate and increase the chance of primary isolation of M. ulcerans bacilli after long turnover time. Methods: Swab and fine needle aspirate (FNA) samples for the primary cultivation were collected from clinically confirmed Buruli ulcer patients in the Mapé Basin of Cameroon. The samples were either stored in the semi-solid transport media 7H9 or Amies or dry for extended period of time prior to processing. In the laboratory, four decontamination methods and two inoculation media were evaluated and statistical methods applied to identify factors that decrease culture contamination and factors that increase the probability of M. ulcerans recovery. Results: The analysis showed: i) that the use of moist transport media significantly increased the recovery rate of M. ulcerans compared to samples kept dry; ii) that the choice of the decontamination method had no significant effect on the chance of M. ulcerans isolation; and iii) that Löwenstein-Jensen supplemented with antibiotics as inoculation medium yielded the best results. We further found that, ten extra days between sampling and inoculation lead to a relative decrease in the isolation rate of M. ulcerans by nearly 20%. Finally, collection and processing of multiple samples per patient was found to significantly increase the M. ulcerans isolation rate. Conclusions: Based on our analysis we suggest a procedure suitable for the primary isolation of M. ulcerans strains from patients following long delay between sample collection and processing to establish a M. ulcerans strain collection for research purposes. © 2014 Bratschi et al.Item Methods used in preclinical assessment of anti-Buruli ulcer agents: A global perspective(Journal of Pharmacological and Toxicological Methods, 2015-05) Tsouh, P.V.F.; Addo, P.; Yeboah-Manu, D.; Boyom, F.F.Buruli ulcer (BU) caused by Mycobacterium ulcerans is the third most common chronic mycobacterial infection in humans. Approximately 5000 cases are reported annually from at least 33 countries around the globe, especially in rural African communities. Even though anti-mycobacterial therapy is often effective for early nodular or ulcerative lesions, surgery is sometimes employed for aiding wound healing and correction of deformities. The usefulness of the antibiotherapy nonetheless is challenged by huge restrictive factors such as high cost, surgical scars and loss of income due to loss of man-hours, and in some instances employment. For these reasons, more effective and safer drugs are urgently needed, and research programs into alternative therapeutics including investigation of natural products should be encouraged. There is the need for appropriate susceptibility testing methods for the evaluation of potency. A number of biological assay methodologies are in current use, ranging from the classical agar and broth dilution assay formats, to radiorespirometric, dye-based, and fluorescent/luminescence reporter assays. Mice, rats, armadillo, guinea pigs, monkeys, grass cutters and lizards have been suggested as animal models for Buruli ulcer. This review presents an overview of in vitro and in vivo susceptibility testing methods developed for the determination of anti-Buruli ulcer activity of natural products and derivatives. Copyright © 2015. Published by Elsevier Inc. Methods used in preclinical assessment of anti-Buruli ulcer agents: A global perspective | Request PDF. Available from: https://www.researchgate.net/publication/273779095_Methods_used_in_preclinical_assessment_of_anti-Buruli_ulcer_agents_A_global_perspective [accessed Sep 18 2018].Item Seasonal Pattern of Mycobacterium ulcerans, the Causative Agent of Buruli Ulcer, in the Environment in Ghana(Microb Ecol, 2017-02) Aboagye, S.Y.; Ampah, K.A.; Ross, A.; Asare, P.; Otchere, I.D.; Fyfe, J.; Yeboah-Manu, D.This study aimed to contribute to the understanding of Mycobacterium ulcerans (MU) ecology by analysing both clinical and environmental samples collected from ten communities along two major river basins (Offin and Densu) associated with Buruli ulcer (BU) at different seasons. We collected clinical samples from presumptive BU cases and environmental samples from ten communities. Following DNA extraction, clinical samples were confirmed by IS2404 PCR and environmental samples were confirmed by targeting MUspecific genes, IS2404, IS2606 and the ketoreductase (KR) using real-time PCR. Environmental samples were first analysed for IS2404; after which, IS2404-positive samples were multiplexed for the IS2606 and KR gene. Our findings indicate an overall decline in BU incidence along both river basins, although incidence at Densu outweighs that of Offin. Overall, 1600 environmental samples were screened along Densu (434, 27 %) and Offin (1166, 73 %) and MU was detected in 139 (9 %) of the combined samples. The positivity of MU along the Densu River basin was 89/434 (20.5 %), whilst that of the Offin River basin was 50/1166 (4.3 %). The DNA was detected mainly in snails (5/6, 83 %), moss (8/40, 20 %), soil (55/586, 9 %) and vegetation (55/675, 8 %). The proportion of MU positive samples recorded was higher during the months with higher rainfall levels (126/ 1175, 11 %) than during the dry season months (13/425, 3 %). This study indicates for the first time that there is a seasonal pattern in the presence of MU in the environment, which may be related to recent rainfall or water in the soil.Item Enhancing buruli ulcer control in Ghana through social interventions: A case study from the obom sub-district(BMC Public Health, 2013) Ahorlu, C.K.; Koka, E.; Yeboah-Manu, D.; Lamptey, I.; Ampadu, E.Background Buruli ulcer is considered a re-emerging disease in West Africa where it has suffered neglect over the years, though children below the age of 16 years are the worst affected in most endemic regions. Due to delayed health seeking, the disease leads to disabilities resulting from amputation and loss of vital organs like the eye leading to school dropout and other social and economic consequences for the affected family. Early treatment with antibiotics is effective; however, this involves daily oral and intramuscular injection at distant health facilities for 56 days making it a challenge among poor rural folks living on daily subsistence work. The mode of transmission of Buruli ulcer is not known and there is no effective preventive vaccine for Buruli ulcer. Thus the only effective control tool is early case detection and treatment to reduce morbidity and associated disabilities that occurs as a result of late treatment. It is therefore essential to implement interventions that remove impediments that limit early case detection; access to early effective treatment and this paper reports one such effort where the feasibility of social interventions to enhance Buruli ulcer control was assessed. Methods This was a qualitative study using in-depth interviews to generate information to ascertain the benefit or otherwise of the intervention implemented. Clinical records of patients to generate data to determine the feasibility and effectiveness of social interventions in the fight against Buruli ulcer was examined. In all, 56 in-depth interviews (28 at baseline and 28 at evaluation) were conducted for this report. Results At full implementation, treatment default and dropout reduced significantly from 58.8% and 52.9% at baseline to 1.5% and 1.5% respectively. The number of early case detection went up significantly. Affected families were happy with social interventions such as provision of transportation and breakfast to patients on daily basis. Families were happy with the outpatient services provided under the intervention where no patient was admitted into the hospital. Conclusion The study showed that with a little more investment in early case detection, diagnosis and treatment, coupled with free transportation and breakfast for patients, most of the cases could be treated effectively with the available antibiotics to avoid disability and complications from the disease.