Yves Thierry Barogui

Detection of Mycobacterium ulcerans in the Environment Predicts Prevalence of Buruli Ulcer in Benin

Background Mycobacterium ulcerans is the causative agent of Buruli ulcer (BU). In West Africa there is an association between BU and residence in low-lying rural villages where aquatic sources are plentiful. Infection occurs through unknown environmental exposure; human-to-human infection is rare. Molecular evidence for M. ulcerans in environmental samples is well documented, but the association of M. ulcerans in the environment with Buruli ulcer has not been studied in West Africa in an area with accurate case data. Methodology/Principal Finding Environmental samples were collected from twenty-five villages in three communes of Benin. Sites sampled included 12 BU endemic villages within the Ouheme and Couffo River drainages and 13 villages near the Mono River and along the coast or ridge where BU has never been identified. Triplicate water filtrand samples from major water sources and samples from three dominant aquatic plant species were collected. Detection of M. ulcerans was based on quantitative polymerase chain reaction. Results show a significant association between M. ulcerans in environmental samples and Buruli ulcer cases in a village (p = 0.0001). A “dose response” was observed in that increasing numbers of M. ulceran- positive environmental samples were associated with increasing prevalence of BU cases (R2 = 0.586). Conclusions/Significance This study provides the first spatial data on the overlap of M. ulcerans in the environment and BU cases in Benin where case data are based on active surveillance. The study also provides the first evidence on M. ulcerans in well-defined non-endemic sites. Most environmental pathogens are more broadly distributed in the environment than in human populations. The congruence of M. ulcerans in the environment and human infection raises the possibility that humans play a role in the ecology of M. ulcerans. Methods developed could be useful for identifying new areas where humans may be at high risk for BU.

Fine-Needle Aspiration, an Efficient Sampling Technique for Bacteriological Diagnosis of Nonulcerative Buruli Ulcer

ABSTRACT Invasive punch or incisional skin biopsy specimens are currently employed for the bacteriological confirmation of the clinical diagnosis of Buruli ulcer (BU), a cutaneous infectious disease caused by Mycobacterium ulcerans. The efficacy of fine-needle aspirates (FNA) using fine-gauge needles (23G by 25 mm) for the laboratory confirmation of BU was compared with that of skin tissue fragments obtained in parallel by excision or punch biopsy. In three BU treatment centers in Benin, both types of diagnostic material were obtained from 33 clinically suspected cases of BU and subjected to the same laboratory analyses: i.e., direct smear examination, IS2404 PCR, and in vitro culture. Twenty-three patients, demonstrating 17 ulcerative and 6 nonulcerative lesions, were positive by at least two tests and were therefore confirmed to have active BU. A total of 68 aspirates and 68 parallel tissue specimens were available from these confirmed patients. When comparing the sensitivities of the three confirmation tests between FNA and tissue specimens, the latter yielded more positive results, but only for PCR was this significant. When only nonulcerative BU lesions were considered, however, the sensitivities of the confirmation tests using FNA and tissue specimens were not significantly different. Our results show that the minimally invasive FNA technique offers enough sensitivity to be used for the diagnosis of BU in nonulcerative lesions.

Healthcare seeking behaviour for Buruli ulcer in Benin: a model to capture therapy choice of patients and healthy community members

Buruli ulcer is a devastating condition emerging in West Africa. We investigated why patients often report late to the hospital. Health seeking behaviour determinants and stigma were studied by in-depth interviews in patients treated in hospital (n=107), patients treated traditionally (n=46) of whom 22 had active disease, and healthy community control subjects (n=107). We developed a model capturing internal and external factors affecting decision making. With increasing severity, extent and duration of Buruli ulcer, a shift of influencing factors on health seeking behaviour appears to occur. Factors causing delay in presenting to hospital were the use of traditional medicine before presenting at the treatment centre; costs and duration of admission; disease considered not serious enough; witchcraft perceived as the cause of disease; and fear of treatment, which patients expected to be amputation. This study confirms the importance of self-treatment and traditional healing in this area. Our study was performed before antimicrobial treatment was introduced in Benin; we suggest that this model and the results from this analysis should be used as a baseline from which to measure the influence of the introduction of antimicrobial treatment on health seeking behaviour for Buruli ulcer in Benin.

Family relationship, water contact and occurrence of Buruli ulcer in Benin.

Background Mycobacterium ulcerans disease (Buruli ulcer) is the most widespread mycobacterial disease in the world after leprosy and tuberculosis. How M. ulcerans is introduced into the skin of humans remains unclear, but it appears that individuals living in the same environment may have different susceptibilities. Objectives This study aims to determine whether frequent contacts with natural water sources, family relationship or the practice of consanguineous marriages are associated with the occurrence of Buruli ulcer (BU). Design Case control study. Setting Department of Atlantique, Benin. Subjects BU-confirmed cases that were diagnosed and followed up at the BU detection and treatment center (CDTUB) of Allada (Department of the Atlantique, Benin) during the period from January 1st, 2006, to June 30th, 2008, with three matched controls (persons who had no signs or symptoms of active or inactive BU) for age, gender and village of residence per case. Main Outcomes Measured Contact with natural water sources, BU history in the family and the practice of consanguineous marriages. Results A total of 416 participants were included in this study, including 104 cases and 312 controls. BU history in the family (p<0.001), adjusted by daily contact with a natural water source (p = 0.007), was significantly associated with higher odds of having BU (OR; 95% CI = 5.5; 3.0–10.0). The practice of consanguineous marriage was not associated with the occurrence of BU (p = 0.40). Mendelian disorders could explain this finding, which may influence individual susceptibility by impairing immunity. Conclusion This study suggests that a combination of genetic factors and behavioral risk factors may increase the susceptibility for developing BU.

Variability of antibiotic susceptibility and toxin production of Staphylococcus aureus strains isolated from skin, soft tissue, and bone related infections.

BackgroundStaphylococcus aureus is an opportunistic commensal bacterium that mostly colonizes the skin and soft tissues. The pathogenicity of S. aureus is due to both its ability to resist antibiotics, and the production of toxins. Here, we characterize a group of genes responsible for toxin production and antibiotic resistance of S. aureus strains isolated from skin, soft tissue, and bone related infections.ResultsA total of 136 S. aureus strains were collected from five different types of infection: furuncles, pyomyositis, abscesses, Buruli ulcers, and osteomyelitis, from hospital admissions and out-patients in Benin. All strains were resistant to benzyl penicillin, while 25% were resistant to methicillin, and all showed sensitivity to vancomycin. Panton-Valentine leukocidin (PVL) was the most commonly produced virulence factor (70%), followed by staphylococcal enterotoxin B (44%). Exfoliative toxin B was produced by 1.3% of the strains, and was only found in isolates from Buruli ulcers. The tsst-1, sec, and seh genes were rarely detected (≤1%).ConclusionsThis study provides new insight into the prevalence of toxin and antibiotic resistance genes in S. aureus strains responsible for skin, soft tissue, and bone infections. Our results showed that PVL was strongly associated with pyomyositis and osteomyelitis, and that there is a high prevalence of PVL-MRSA skin infections in Benin.

Histopathological Changes and Clinical Responses of Buruli Ulcer Plaque Lesions during Chemotherapy: A Role for Surgical Removal of Necrotic Tissue?

Background Buruli ulcer (BU) caused by Mycobacterium ulcerans is a necrotizing skin disease usually starting with a subcutaneous nodule or plaque, which may ulcerate and progress, if untreated, over months and years. During the currently recommended antibiotic treatment with rifampicin/streptomycin plaque lesions tend to ulcerate, often associated with retarded wound healing and prolonged hospital stays. Methodology/Principal Findings Included in this study were twelve laboratory reconfirmed, HIV negative BU patients presenting with plaque lesions at the CDTUB in Allada, Benin. Punch biopsies for histopathological and immunohistochemical analysis were taken before start of treatment and after four to five weeks of treatment. Where excision or wound debridement was clinically indicated, the removed tissue was also analyzed. Based on clinical judgment, nine of the twelve patients enrolled in this study received limited surgical excision seven to 39 days after completion of chemotherapy, followed by skin grafting. Lesions of three patients healed without further intervention. Before treatment, plaque lesions were characterized by a destroyed subcutis with extensive necrosis without major signs of infiltration. After completion of antibiotic treatment partial infiltration of the affected tissue was observed, but large necrotic areas remained unchanged. Conclusion/Significance Our histopathological analyses show that ulceration of plaque lesions during antibiotic treatment do not represent a failure to respond to antimycobacterial treatment. Based on our results we suggest formal testing in a controlled clinical trial setting whether limited surgical excision of necrotic tissue favours wound healing and can reduce the duration of hospital stays.

Case Report: Severe Multifocal Form of Buruli Ulcer after Streptomycin and Rifampin Treatment: Comments on Possible Dissemination Mechanisms

Buruli ulcer (BU), a disease caused by Mycobacterium ulcerans, leads to the destruction of skin and sometimes bone. Here, we report a case of severe multifocal BU with osteomyelitis in a 6-year-old human immunodeficiency virus (HIV)-negative boy. Such disseminated forms are poorly documented and generally occur in patients with HIV co-infection. The advent of antibiotic treatment with streptomycin (S) and rifampin (R) raised hope that these multifocal BU cases could be reduced. The present case raises two relevant points about multifocal BU: the mechanism of dissemination that leads to the development of multiple foci and the difficulties of treatment of multifocal forms of BU. Biochemical (hypoproteinemia), hematological (anemia), clinical (traditional treatment), and genetic factors are discussed as possible risk factors for dissemination.

Contribution of the community health volunteers in the control of Buruli ulcer in Bénin.

Background Buruli ulcer (BU) is a neglected tropical disease caused by Mycobacterium ulcerans. Usually BU begins as a painless nodule, plaque or edema, ultimately developing into an ulcer. The high number of patients presenting with ulcers in an advanced stage is striking. Such late presentation will complicate treatment and have long-term disabilities as a consequence. The disease is mainly endemic in West Africa. The primary strategy for control of this disease is early detection using community village volunteers. Methodology/Principal Findings In this retrospective, observational study, information regarding Buruli ulcer patients that reported to one of the four BU centers in Bénin between January 2008 and December 2010 was collected using the WHO/BU01 forms. Information used from these forms included general characteristics of the patient, the results of diagnostic tests, the presence of functional limitations at start of treatment, lesion size, patient delay and the referral system. The role of the different referral systems on the stage of disease at presentation in the hospital was analyzed by a logistic regression analysis. About a quarter of the patients (26.5%) were referred to the hospital by the community health volunteers. In our data set, patients referred to the hospital by community health volunteers appeared to be in an earlier stage of disease than patients referred by other methods, but after adjustment by the regression analysis for the health center, this effect could no longer be seen. The Polymerase Chain Reaction (PCR) for IS2404 positivity rate among patients referred by the community health volunteers was not systematically lower than in patients referred by other systems. Conclusions/Significance This study clarifies the role played by community health volunteers in Bénin, and shows that they play an important role in the control of BU.

Towards Rational Use of Antibiotics for Suspected Secondary Infections in Buruli Ulcer Patients

Background The emerging disease Buruli ulcer is treated with streptomycin and rifampicin and surgery if necessary. Frequently other antibiotics are used during treatment. Methods/Principal Findings Information on prescribing behavior of antibiotics for suspected secondary infections and for prophylactic use was collected retrospectively. Of 185 patients that started treatment for Buruli ulcer in different centers in Ghana and Bénin 51 were admitted. Forty of these 51 admitted patients (78%) received at least one course of antibiotics other than streptomycin and rifampicin during their hospital stay. The median number (IQR) of antibiotic courses for admitted patients was 2 (1, 5). Only twelve patients received antibiotics for a suspected secondary infection, all other courses were prescribed as prophylaxis of secondary infections extended till 10 days on average after excision, debridement or skin grafting. Antibiotic regimens varied considerably per indication. In another group of BU patients in two centers in Bénin , superficial wound cultures were performed. These cultures from superficial swabs represented bacteria to be expected from a chronic wound, but 13 of the 34 (38%) S. aureus were MRSA. Conclusions/Significance A guide for rational antibiotic treatment for suspected secondary infections or prophylaxis is needed. Adherence to the guideline proposed in this article may reduce and tailor antibiotic use other than streptomycin and rifampicin in Buruli ulcer patients. It may save costs, reduce toxicity and limit development of further antimicrobial resistance. This topic should be included in general protocols on the management of Buruli ulcer.

Persisting Social Participation Restrictions among Former Buruli Ulcer Patients in Ghana and Benin

Background Buruli ulcer may induce severe disabilities impacting on a persons well-being and quality of life. Information about long-term disabilities and participation restrictions is scanty. The objective of this study was to gain insight into participation restrictions among former Buruli ulcer patients in Ghana and Benin. Methods In this cross-sectional study, former Buruli ulcer patients were interviewed using the Participation Scale, the Buruli Ulcer Functional Limitation Score to measure functional limitations, and the Explanatory Model Interview Catalogue to measure perceived stigma. Healthy community controls were also interviewed using the Participation Scale. Trained native interviewers conducted the interviews. Former Buruli ulcer patients were eligible for inclusion if they had been treated between 2005 and 2011, had ended treatment at least 3 months before the interview, and were at least 15 years of age. Results In total, 143 former Buruli ulcer patients and 106 community controls from Ghana and Benin were included in the study. Participation restrictions were experienced by 67 former patients (median score, 30, IQR; 23;43) while 76 participated in social life without problems (median score 5, IQR; 2;9). Most restrictions encountered related to employment. Linear regression showed being female, perceived stigma, functional limitations, and larger lesions (category II) as predictors of more participation restrictions. Conclusion Persisting participation restrictions were experienced by former BU patients in Ghana and Benin. Most important predictors of participation restrictions were being female, perceived stigma, functional limitations and larger lesions.