Browsing by Author "Sarfo, Fred Stephen"

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    Clinical and Bacteriological Efficacy of Rifampin-Streptomycin Combination for Two Weeks followed by Rifampin and Clarithromycin for Six Weeks for Treatment of Mycobacterium ulcerans Disease
    (Antimicrobial Agents and Chemotherapy, 2014-02) Phillips, Richard Odame; Sarfo, Fred Stephen; Abass, Mohammed K.; Abotsi, Justice; Wilson, Tuah; Forson, Mark; Amoako, Yaw A.; Thompson, William; Asiedu, Kingsley; Wansbrough-Jonesc, Mark Wansbrough-Jonesc
    Buruli ulcer, an ulcerating skin disease caused by Mycobacterium ulcerans infection, is common in tropical areas of western Africa. We determined the clinical and microbiological responses to administration of rifampin and streptomycin for 2 weeks followed by administration of rifampin and clarithromycin for 6 weeks in 43 patients with small laboratory-confirmed Buruli lesions and monitored for recurrence-free healing. Bacterial load in tissue samples before and after treatment for 6 and 12 weeks was monitored by semiquantitative culture. The success rate was 93%, and there was no recurrence after a 12-month follow-up. Eight percent had a positive culture 4 weeks after antibiotic treatment, but their lesions went on to heal. The findings indicate that rifampin and clarithromycin can replace rifampin and streptomycin for the continuation phase after rifampin and streptomycin administration for 2 weeks without any apparent loss of efficacy.
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    Clinical Efficacy of Combination of Rifampin and Streptomycin for Treatment of Mycobacterium ulcerans Disease
    (Antimicrobial Agents and Chemotherapy, 2010-09) Sarfo, Fred Stephen; Phillips, Richard Odame; Asiedu, Kingsley; Ampadu, Edwin; Bobi, Nana; et.al
    We have evaluated the clinical efficacy of the combination of oral rifampin at 10 mg/kg of body weight and intramuscular streptomycin at 15 mg/kg for 8 weeks (RS8), as recommended by the WHO, in 160 PCRconfirmed cases of Mycobacterium ulcerans disease. In 152 patients (95%) with all forms of disease from early nodules to large ulcers, with or without edema, the lesions healed without recourse to surgery. Eight patients whose ulcers were healing poorly had skin grafting after completion of antibiotics. There were no recurrences among 158 patients reviewed at the 1-year follow-up. The times to complete healing ranged from 2 to 48 weeks, according to the type and size of the lesion, but the average rate of healing (rate of reduction in ulcer diameter) varied widely. Thirteen subjects had positive cultures for M. ulcerans during or after treatment, but all the lesions healed without further antibiotic treatment. Adverse events were rare. These results confirm the efficacy of RS8 delivered in a community setting.
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    Combined Inflammatory and Metabolic Defects Reflected by Reduced Serum Protein Levels in Patients with Buruli Ulcer Disease
    (PLOS Neglected Tropical Diseases, 2014-04-10) Phillips, Richard Odame; Sarfo, Fred Stephen; Landier, Jordi; Oldenburg, Reid; Frimpong, Michael; et. al
    Buruli ulcer is a skin disease caused by Mycobacterium ulcerans that is spreading in tropical countries, with major public health and economic implications in West Africa. Multi-analyte profiling of serum proteins in patients and endemic controls revealed that Buruli ulcer disease down-regulates the circulating levels of a large array of inflammatory mediators, without impacting on the leukocyte composition of peripheral blood. Notably, several proteins contributing to acute phase reaction, lipid metabolism, coagulation and tissue remodelling were also impacted. Their down-regulation was selective and persisted after the elimination of bacteria with antibiotic therapy. It involved proteins with various functions and origins, suggesting that M. ulcerans infection causes global and chronic defects in the host’s protein metabolism. Accordingly, patients had reduced levels of total serum proteins and blood urea, in the absence of signs of malnutrition, or functional failure of liver or kidney. Interestingly, slow healers had deeper metabolic and coagulation defects at the start of antibiotic therapy. In addition to providing novel insight into Buruli ulcer pathogenesis, our study therefore identifies a unique proteomic signature for this disease.
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    Cytokine Response to Antigen Stimulation of Whole Blood from Patients with Mycobacterium ulcerans Disease Compared to That from Patients with Tuberculosis
    (American Society for Microbiology, 2006-02) Phillips, Richard Odame; Horsfield, C.; Kuijper, S.; Sarfo, Fred Stephen; Obeng-Baah, J.; et.al
    Mycobacterium ulcerans disease (Buruli ulcer) is a skin-ulcerating infection common in some parts of the tropics. We have investigated cytokine secretion after stimulation of whole blood from Buruli ulcer (BU) patients in a region of endemicity in Ghana with M. ulcerans sonicate or culture filtrate antigens to investigate the development of the response over time and its specificity by comparison with the response to Mycobacterium tuberculosis sonicate in human immunodeficiency virus-negative tuberculosis patients. Significant gamma interferon (IFN- ) production in response to whole-blood stimulation with M. ulcerans sonicate was detected in patients with ulcers, which was higher than that in patients with nodules but similar to subjects with healed BU. The mean IFN- response in household contacts of BU patients was not significantly different from that in healthy control subjects from an area of nonendemicity. Results in patients with untreated, smear-positive pulmonary tuberculosis and tuberculosis patients on treatment for more than 2 weeks showed that BU patients responded better to M. ulcerans antigens than tuberculosis patients. In contrast, interleukin-10 results were higher in patients with active M. ulcerans disease than in those with healed lesions, but the pattern of response was similar to that seen in tuberculosis. A similar pattern of cytokine secretion was found using M. tuberculosis sonicate as an antigen. Neither of the two culture filtrate antigens of M. ulcerans appeared to be more specific than M. ulcerans sonicate. In the early stages of M. ulcerans disease there was a mixed Th1 and Th2 cytokine response, but the Th1 response emerged as the dominant type.
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    Detection of Highly Prevalent Hepatitis B Virus Coinfection among HIV-Seropositive Persons in Ghana
    (American Society for Microbiology, 2010-09) Geretti, Anna Maria; Patel, Mauli; Sarfo, Fred Stephen; Phillips, Richard Odame; Chadwick, David; et.al
    Simple hepatitis B surface antigen (HBsAg) tests may facilitate ascertainment of hepatitis B virus (HBV) infection in settings with high endemicity but limited infrastructure. We evaluated two rapid HBsAg tests and characterized HBV coinfection in a Ghanaian HIV-positive cohort. Samples from 838 patients were tested by the rapid assays Determine and Vikia and the reference assays Architect, Murex version 3, and Liaison Ultra. The assays were also evaluated using the 2nd International Standard, a seroconversion panel, and two mutant panels. HBsAg-positive samples underwent HBV DNA quantification by real-time PCR and surface and polymerase gene population sequencing. Overall, 140/838 patients (16.7%; 95% confidence interval, 14.2 to 19.2%) were HBsAg positive, and of these, 103/140 (73.6%) were e-antigen negative and 118/140 (84.3%) showed an HBV DNA level of >14 IU/ml (median, 8,279 IU/ml). Assay sensitivities and specificities were as follows: Architect, 97.9 and 99.6%; Liaison, 97.1 and 99.4%; Murex, 98.6 and 99.3%; Determine, 69.3 and 100%; and Vikia, 70.7 and 100%. With Determine, the limit of detection was >1.5 to 3.4 HBsAg IU/ml, and the median HBV DNA loads were 598 and 10,905 IU/ml in Determine-negative and -positive samples, respectively (P 0.0005). Results were similar with the Vikia assay. HBV DNA sequencing indicated infection with genotype E in 82/86 (95.3%) patients. HBsAg mutations affected assay performance, including a T123A mutant that escaped detection by Architect. Major drug resistance mutations were observed in 4/86 patients (4.6%). The prevalence of HBV coinfection was high in this HIV-positive Ghanaian cohort. The two rapid assays identified HBsAg-positive patients at risk for liver disease with high specificity, albeit with only moderate sensitivity.
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    Detection of Mycolactone A/B in Mycobacterium ulcerans–Infected Human Tissue
    (PLoS Neglected Tropical Diseases, 2010-01-05) Sarfo, Fred Stephen; Phillips, Richard Odame; Rangers, Brian; Mahrous, Engy A.; Lee, Richard E.; et. al
    Background: Mycobacterium ulcerans disease (Buruli ulcer) is a neglected tropical disease common amongst children in rural West Africa. Animal experiments have shown that tissue destruction is caused by a toxin called mycolactone. Methodology/Principal Findings: A molecule was identified among acetone-soluble lipid extracts from M. ulcerans (Mu)- infected human lesions with chemical and biological properties of mycolactone A/B. On thin layer chromatography this molecule had a retention factor value of 0.23, MS analyses showed it had an m/z of 765.6 [M+Na+] and on MS:MS fragmented to produce the core lactone ring with m/z of 429.4 and the polyketide side chain of mycolactone A/B with m/z of 359.2. Acetone-soluble lipids from lesions demonstrated significant cytotoxic, pro-apoptotic and anti-inflammatory activities on cultured fibroblast and macrophage cell lines. Mycolactone A/B was detected in all of 10 tissue samples from patients with ulcerative and pre-ulcerative Mu disease. Conclusions/Significance: Mycolactone can be detected in human tissue infected with Mu. This could have important implications for successful management of Mu infection by antibiotic treatment but further studies are needed to measure its concentration.
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    Differential Impact of Risk Factors on Stroke Occurrence Among Men Versus Women in West Africa The SIREN Study
    (Stroke, 2019) Akpalu, Albert; Gebregziabher, Mulugeta; Ovbiagele, Bruce; Sarfo, Fred Stephen; Iheonye, Henry; Akinyemi, Rufus; Akpa, Onoja...et.al.
    Background and Purpose—The interplay between sex and the dominant risk factors for stroke occurrence in sub-Saharan Africa has not been clearly delineated. We compared the effect sizes of risk factors of stroke by sex among West Africans. Methods—SIREN study (Stroke Investigative Research and Educational Networks) is a case-control study conducted at 15 sites in Ghana and Nigeria. Cases were adults aged >18 years with computerized tomography/magnetic resonance imaging confirmed stroke, and controls were age- and sex-matched stroke-free adults. Comprehensive evaluation for vascular, lifestyle, and psychosocial factors was performed using validated tools. We used conditional logistic regression to estimate odds ratios and reported risk factor specific and composite population attributable risks with 95% CIs. Results—Of the 2118 stroke cases, 1193 (56.3%) were males. The mean±SD age of males was 58.1±13.2 versus 60.15±14.53 years among females. Shared modifiable risk factors for stroke with adjusted odds ratios (95% CI) among females versus males, respectively, were hypertension [29.95 (12.49–71.77) versus 16.1 0(9.19–28.19)], dyslipidemia [2.08 (1.42–3.06) versus 1.83 (1.29–2.59)], diabetes mellitus [3.18 (2.11–4.78) versus 2.19 (1.53–3.15)], stress [2.34 (1.48–3.67) versus 1.61 (1.07–2.43)], and low consumption of green leafy vegetables [2.92 (1.89–4.50) versus 2.00 (1.33–3.00)]. However, salt intake and income were significantly different between males and females. Six modifiable factors had a combined population attributable risk of 99.1% (98.3%–99.6%) among females with 9 factors accounting for 97.2% (94.9%–98.7%) among males. Hemorrhagic stroke was more common among males (36.0%) than among females (27.6%), but stroke was less severe among males than females. Conclusions—Overall, risk factors for stroke occurrence are commonly shared by both sexes in West Africa favoring concerted interventions for stroke prevention in the region.
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    Dynamics of the Cytokine Response to Mycobacterium ulcerans during Antibiotic Treatment for M. ulcerans Disease (Buruli Ulcer) in Humans
    (American Society for Microbiology, 2009-01) Sarfo, Fred Stephen; Phillips, Richard Odame; Ampadu, E.; Sarpong, F.; Adentwe, E.; et.al
    We have studied the evolution of the gamma interferon (IFN- ) and interleukin 10 (IL-10) responses after Mycobacterium ulcerans sonicate stimulation of whole blood from patients with early M. ulcerans lesions during treatment with rifampin and streptomycin for 8 weeks. Among the 26 patients, secretion of IFN- increased during treatment, with a significant increase at 4 weeks and a further increase after 8 weeks overall. The increase was more rapid in patients with large or ulcerative lesions, becoming significant by 4 weeks. For small lesions, there was only a minor increase, which did not reach significance. There was no significant change in the median IL-10 response during antibiotic therapy, and there was no inverse correlation between IFN- and IL-10 responses. These results demonstrate that an IFN- secretory response to M. ulcerans developed, independently of IL-10 secretion, in patients whose M. ulcerans disease healed during antibiotic therapy.
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    Genetic Diversity of PCR-Positive, Culture-Negative and Culture-Positive Mycobacterium ulcerans Isolated from Buruli Ulcer Patients in Ghana
    (PLOS One, 2014-02-10) Williamson, Heather; Phillips, Richard Odame; Sarfo, Fred Stephen; Wansbrough-Jones, Mark; Small, Pamela
    Culture of Mycobacterium ulcerans from Buruli ulcer patients has very low sensitivity. Thus confirmation of M. ulcerans infection is primarily based on PCR directed against IS2404. In this study we compare the genotypes obtained by variable number of tandem repeat analysis of DNA from IS2404-PCR positive cultures with that obtained from IS2404 positive, culture-negative tissue. A significantly greater genetic heterogeneity was found among culture-negative samples compared with that found in cultured strains but a single genotype is over-represented in both sample sets. This study provides evidence that both the focal location of bacteria in a lesion as well as differences in the ability to culture a particular genotype may underlie the low sensitivity of culture. Though preliminary, data from this work also suggests that mycobacteria previously associated with fish disease (M. pseudoshottsii) may be pathogenic for humans.
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    Helicobacter pylori Coinfection Is Associated With Decreased Markers of Immune Activation in ART-Naive HIV-Positive and in HIV-Negative Individuals in Ghana
    (Oxford University Press, 2015-11-15) Phillips, Richard Odame; Eberhardt, Kirsten Alexandra; Sarfo, Fred Stephen; Dompreh, Albert; Kuffour, Edmund Osei; et. al
    Background. Helicobacter pylori coinfection in human immunodeficiency virus (HIV) patients has been associated with higher CD4+ cell counts and lower HIV-1 viral loads, with the underlying mechanisms being unknown. The objective of this study was to investigate the impact of H. pylori infection on markers of T-cell activation in HIVpositive and HIV-negative individuals. Methods. In a cross-sectional, observational study, HIV patients (n = 457) and HIV-negative blood donors (n = 79) presenting to an HIV clinic in Ghana were enrolled. Data on clinical and sociodemographic parameters, CD4+/CD8+ T-cell counts, and HIV-1 viral load were recorded. Helicobacter pylori status was tested using a stool antigen test. Cell surface and intracellular markers related to T-cell immune activation and turnover were quantified by flow cytometry and compared according to HIV and H. pylori status. Results. Helicobacter pylori infection was associated with decreased markers of CD4+ T-cell activation (HLADR+ CD38+CD4+; 22.55% vs 32.70%; P = .002), cell proliferation (Ki67; 15.10% vs 26.80%; P = .016), and immune exhaustion (PD-1; 32.45% vs 40.00%; P = .005) in 243 antiretroviral therapy (ART)–naive patients, but not in 214 patients on ART. In HIV-negative individuals, H. pylori infection was associated with decreased frequencies of activated CD4+ and CD8+ T cells (6.31% vs 10.40%; P = .014 and 18.70% vs 34.85%, P = .006, respectively). Conclusions. Our findings suggest that H. pylori coinfection effectuates a systemic immune modulatory effect with decreased T-cell activation in HIV-positive, ART-naive patients but also in HIV-negative individuals. This findingmight, in part, explain the observed association of H. pylori infection with favorable parameters of HIV disease progression. Clinical Trials Registration. Clinicaltrials.gov NCT01897909.
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    High Frequency of Active HCV Infection Among Seropositive Cases in West Africa and Evidence for Multiple Transmission Pathways
    (Oxford University Press, 2014-12-04) Layden, Jennifer E.; Phillips, Richard Odame; Owusu-Ofori, Shirley; Sarfo, Fred Stephen; Kliethermes, Stephanie; et.al
    Sub-Saharan Africa (SSA) has one of the highest global hepatitis C virus (HCV) prevalence estimates. However, reports that suggest high rates of serologic false positives and low levels of viremia have led to uncertainty regarding the burden of active infection in this region. Additionally, little is known about the predominant transmission risk factors in SSA.
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    High frequency of active HCV infection among seropositives in West Africa and evidence for multiple transmission pathways
    (Journal of Hepatology, 2015) Phillips, Richard Odame; Layden, J.; Mora, N.; Owusi-Ofori, S.; Sarfo, Fred Stephen; et. al
    Background and Aims: Sub-Saharan Africa (SSA) has among the highest global Hepatitis C Virus (HCV) sero-prevalence estimates. However, reports suggesting high rates of serologic false positives and low levels of detectable viremia has led to uncertainty regarding the burden of active HCV infection in this region. Additionally, little is known about the predominant transmission risk factors and mechanisms in this region. The aims of this study were to determine the frequency of active infection among persons who screened positive for HCV infection and identify risk factors for HCV infection. Methods: Between May 2013 and January 2014 we recalled 363 blood donors [180 rapid screen assay (RSA) (Accu-Tell HCV) positive and 183 RSA negative at time of donation] to identify the level of active infection and risk factors at Komfo Anokye Teaching Hospital in Kumasi, Ghana. Participants had blood drawn for serologic and virologic testing (HBVsAg Abbott Architect CIA, HIV 4th generation Ab/Ag test, the HCV Advia Centaur HCV CIA, and Abbott RealTime PCR assay for HCVRNA quantitative levels). HCV genotypes were determined by the generated NS5b sequences (SuperScript® VILO™ cDNA Synthesis Kit). A questionnaire on demographics and risk factors was administered. Results: The frequency of active infection varied based on serologic testing results, but was overall high. In subjects with a positive CIA Serologic Antibody Assay [Signal to Cut-off ratio (S/C) >1], the rate of active viremia was 74.4%, and increased to 88% among the individuals with a CIA S/C ≥11. Individuals were predominantly infected with genotype 2, and the median viral load among actively infected individuals was 5.75 log cp/ml. Blood donors from the northern and upper regions of Ghana had substantially higher risks of infection compared to those from the middle belt. Individual level Odds ratio statistical significant risk factors included: traditional circumcision (3.8), home birth (2.0), tribal scarring (2.2) and HBV co-infection (2.7). See Table 1. Conclusions: Among serologically confirmed cases, active infection rates were high. Appropriate testing algorithms should be widely implemented to define the true HCV burden in SSA. These data also suggest that several transmission modes, particularly those associated with cultural skin-piercing practices, are likely contributing to the current HCV epidemic in Ghana, and the distribution of these practices may result in regional variation in prevalence.
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    High prevalence of renal dysfunction and association with risk of death amongst HIV-infected Ghanaians
    (Elsevier Ltd., 2013-03-28) Phillips, Richard Odame; Shakoor, Shaid; Appiah, Lambert; Keegan, Rosie; Sarfo, Fred Stephen; et.al
    To determine the prevalence of HIV-associated renal dysfunction (RD), identify risk factors for RD and explore the association between baseline renal function and mortality in an HIV-infected population in Ghana. Methods: Creatinine clearance (CrCl) or estimated glomerular filtration rate (eGFR) was calculated in patients attending an HIV clinic between 2004 and 2011 using Cockcroft-Gault, MDRD and CKD-EPI formulae. Logistic regression analysis was used to identify risk factors associated with RD and KaplaneMeier/Cox proportional regression analyses to explore associations between baseline CrCl/eGFR and subsequent mortality. Results: In 3137 patients starting antiretroviral therapy (ART) the frequency (95%-CI) of RD, defined by CrCl <60 ml/min/1.73 m2 using Cockroft-Gault formula was 38.8% (37.1e40.5%). RD prevalence in a sub-population of 238 patients, including proteinuria in the definition, was 15.3% (10.3e22.1%) in ART-treated and 43.6% (34.0e53.7%) in ART-na€ıve patients. RD at baseline was associated with increasing age, low CD4 counts, advanced WHO stage and female gender. Cox proportional hazard analysis identified an increased hazard of death with decreasing CrCl, HR 1.46 (1.31e1.63) for each tertile lower than CrCl of 90 ml/min/1.73 m2. Conclusions: RD is very common in HIV-infected ART-na€ıve Ghanaians, and associated with increased risk of mortality. Screening and monitoring of RD is important in this setting, particularly as tenofovir use increases.
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    IFN-g and IL-5 whole blood response directed against mycolactone polyketide synthase domains in patients with Mycobacterium ulcerans infection
    (PeerJ, 2018-07-31) Phillips, Richard Odame; Loglo, Aloysius D.; Frimpong, Michael; Duah, Mabel Sarpong; Sarfo, Fred Stephen; et. al
    Background: Buruli ulcer is a disease of the skin and soft tissues caused by infection with a slow growing pathogen, Mycobacterium ulcerans. A vaccine for this disease is not available but M. ulcerans possesses a giant plasmid pMUM001 that harbours the polyketide synthase (PKS) genes encoding a multi-enzyme complex needed for the production of its unique lipid toxin called mycolactone, which is central to the pathogenesis of Buruli ulcer. We have studied the immunogenicity of enzymatic domains in humans with M. ulcerans disease, their contacts, as well as non-endemic areas controls. Methods: Between March 2013 and August 2015, heparinized whole blood was obtained from patients confirmed with Buruli ulcer. The blood samples were diluted 1 in 10 in Roswell Park Memorial Institute (RPMI) medium and incubated for 5 days with recombinant mycolactone PKS domains and mycolyltransferase antigen 85A (Ag85A). Blood samples were obtained before and at completion of antibiotic treatment for 8 weeks and again 8 weeks after completion of treatment. Supernatants were assayed for interferon-g (IFN-g) and interleukin-5 (IL-5) by enzyme-linked immunosorbent assay. Responses were compared with those of contacts and non-endemic controls. Results: More than 80% of patients and contacts from endemic areas produced IFN-g in response to all the antigens except acyl carrier protein type 3 (ACP3) to which only 47% of active Buruli ulcer cases and 71% of contacts responded. The highest proportion of responders in cases and contacts was to load module ketosynthase domain (Ksalt) (100%) and enoylreductase (100%). Lower IL-5 responses were induced in a smaller proportion of patients ranging from 54% after ketoreductase type B stimulation to only 21% with ketosynthase type C (KS C). Among endemic area contacts, the, highest proportion was 73% responding to KS C and the lowest was 40% responding to acyltransferase with acetate specificity type 2. Contacts of Buruli ulcer patients produced significantly higher IFN-g and IL-5 responses compared with those of patients to PKS domain antigens and to mycolyltransferase Ag85A of M. ulcerans. There was low or no response to all the antigens in non-endemic areas controls. IFN-g and IL-5 responses of patients improved after treatment when compared to baseline results. Discussion: The major response to PKS antigen stimulation was IFN-g and the strongest responses were observed in healthy contacts of patients living in areas endemic for Buruli ulcer. Patients elicited lower responses than healthy contacts, possibly due to the immunosuppressive effect of mycolactone, but the responses were enhanced after antibiotic treatment. A vaccine made up of the most immunogenic PKS domains combined with the mycolyltransferase Ag85A warrants further investigation.
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    Immunosuppressive Signature of Cutaneous Mycobacterium ulcerans Infection in the Peripheral Blood of Patients with Buruli Ulcer Disease
    (Infectious Diseases Society of America, 2009-10-28) Phillips, Richard Odame; Sarfo, Fred Stephen; Guenin-Mace, Laure; Wansbrough-Jones, Mark; Albert, Matthew L.; et. al
    Buruli ulcer disease (BUD) is an emerging human disease caused by infection with Mycobacterium ulcerans, which leads to the development of necrotic skin lesions. The pathogenesis of the ulcer is closely associated with the production of mycolactone, a diffusible cytotoxin with immunomodulatory properties. To identify immunological correlates of BUD, we performed a broad screen of inflammatory mediators in serum samples and stimulated whole-blood supernatants of patients. We found that patients with active ulcers displayed a distinctive profile of immune suppression, marked by the down-modulation of selected chemokines and an impaired capacity to produce Th1, Th2, and Th17 cytokines on stimulation with mitogenic agents. These immunological defects were induced early in the disease and resolved after anti-BUD therapy, establishing their association with the presence of M. ulcerans. Interestingly, some of the defects in cytokine and chemokine response could be mimicked in vitro by incubation of CD4+ peripheral blood lymphocytes with mycolactone. Our findings support the hypothesis that mycolactone contributes to bacterial persistence in human hosts by limiting the generation of adaptive cellular responses. Moreover, we identified immunological markers of BUD, which may be helpful for confirmatory diagnosis of the disease and, especially, for monitoring the response to antibiotic treatment.
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    Infection with Mansonella perstans Nematodes in Buruli Ulcer Patients, Ghana
    (Emerging Infectious Diseases, 2014-06-06) Phillips, Richard Odame; Frimpong, Michael; Sarfo, Fred Stephen; Kretschmer, Birte; Beissner, Marcus; et. al
    During August 2010–December 2012, we conducted a study of patients in Ghana who had Buruli ulcer, caused by Mycobacterium ulcerans, and found that 23% were coinfected with Mansonella perstans nematodes; 13% of controls also had M. perstans infection. M. perstans co-infection should be considered in the diagnosis and treatment of Buruli ulcer.
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    The kinetics of mycolactone in relation to the microbiological, clinical and immunological responses to antibiotic therapy for mycobacterium ulcerans disease.
    (2014-11-20) Sarfo, Fred Stephen
    Background: Mycobacterium ulcerans is the causative agent for a chronic necrotising skin infection called Buruli ulcer. Pathology of the disease is closely linked with the elaboration of a unique lipid toxin, mycolactone, which has potent cytotoxic and immunomodulatory properties. In this study, assays were developed to detect and quantify mycolactone concentrations in tissues during curative antibiotic therapy in mice and in humans to understand its dynamics in pathogenesis and to explore its potential as a biomarker for diagnosis and monitoring of patients with Buruli ulcer disease on antibiotic therapy. The currently recommended antibiotic regimen for the management of Buruli ulcer is a combination of daily intramuscular injections of streptomycin and oral rifampicin for 8 weeks (RS8). This regimen was compared with streptomycin/rifampicin for 2 weeks followed by clarithromycin/rifampicin (RS2RC6) for 6 weeks in patients to determine the clinical and bacteriological effectiveness in a pilot study. Methods: Biopsies were obtained from infected human skin tissues and BALB/c mouse hind footpads before, during and after 8-weeks of rifampicin-containing combination antibiotic therapy. Lipids were extracted from tissues using organic solvents, mycolactone concentrations were measured using a cytotoxicity assay and mass spectrometry. Trends in mycolactone concentrations and clinical, bacteriological and immuno-histopathological responses were determined. Concentrations of cytokines in supernates of whole blood assays in humans or murine splenocytes after stimulation with mycobacterial antigens/T-cell mitogens were measured using ELISA. iv Results: Eighty-three patients with confirmed Buruli ulcer were randomized to RS8 or RS2RC6 and monitored for recurrence free-healing. Bacterial load in tissue samples before and after treatment for 6 and 12 weeks was monitored in samples obtained by 4mm punch biopsy by semi-quantitative culture. There was no difference in using RS8 or RS2RC6 with respect to healing rate or the proportion healed in each group after 4, 8, 12, 16, 20, 24 and up to 52 weeks. The success rate was 93% in each group and there was no recurrence after 12-month follow-up. There was no difference in the number of bacteria cultured at the different time points for the two regimens. Mycolactone was detectable in 92% and 77% of human samples (n=80) using cytotoxicity assays and mass spectrometry respectively. Antibiotic therapy was associated with a decline in tissue concentration of mycolactone in both human and murine-infected tissues which was paralleled by resolution of clinical lesions, reductions in bacteriological counts and restoration of local and systemic immune responses. Discussions/Conclusions: This study shows that mycolactone concentrations in tissues is closely associated with the presence of M. ulcerans and provides useful proof-of-concept data that mycolactone detection could potentially be used to monitor response to antibiotic therapy as well as for diagnosis of Buruli ulcer disease. The findings from the pilot study indicate that rifampicin combined with clarithromycin can replace rifampicin and streptomycin for the continuation phase after rifampicin-streptomycin treatment for 2 weeks without any apparent loss of efficacy. The implication is that a controlled trial of fully oral therapy using rifampicin and clarithromycin for 8 weeks (RC8) is justified.
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    The kinetics of mycolactone in relation to the microbiological, clinical and immunological responses to antibiotic therapy for mycobacterium ulcerans disease.
    (2014) Sarfo, Fred Stephen
    Background: Mycobacterium ulcerans is the causative agent for a chronic necrotising skin infection called Buruli ulcer. Pathology of the disease is closely linked with the elaboration of a unique lipid toxin, mycolactone, which has potent cytotoxic and immunomodulatory properties. In this study, assays were developed to detect and quantify mycolactone concentrations in tissues during curative antibiotic therapy in mice and in humans to understand its dynamics in pathogenesis and to explore its potential as a biomarker for diagnosis and monitoring of patients with Buruli ulcer disease on antibiotic therapy. The currently recommended antibiotic regimen for the management of Buruli ulcer is a combination of daily intramuscular injections of streptomycin and oral rifampicin for 8 weeks (RS8). This regimen was compared with streptomycin/rifampicin for 2 weeks followed by clarithromycin/rifampicin (RS2RC6) for 6 weeks in patients to determine the clinical and bacteriological effectiveness in a pilot study. Methods: Biopsies were obtained from infected human skin tissues and BALB/c mouse hind footpads before, during and after 8-weeks of rifampicin-containing combination antibiotic therapy. Lipids were extracted from tissues using organic solvents, mycolactone concentrations were measured using a cytotoxicity assay and mass spectrometry. Trends in mycolactone concentrations and clinical, bacteriological and immuno-histopathological responses were determined. Concentrations of cytokines in supernates of whole blood assays in humans or murine splenocytes after stimulation with mycobacterial antigens/T-cell mitogens were measured using ELISA. iv Results: Eighty-three patients with confirmed Buruli ulcer were randomized to RS8 or RS2RC6 and monitored for recurrence free-healing. Bacterial load in tissue samples before and after treatment for 6 and 12 weeks was monitored in samples obtained by 4mm punch biopsy by semi-quantitative culture. There was no difference in using RS8 or RS2RC6 with respect to healing rate or the proportion healed in each group after 4, 8, 12, 16, 20, 24 and up to 52 weeks. The success rate was 93% in each group and there was no recurrence after 12-month follow-up. There was no difference in the number of bacteria cultured at the different time points for the two regimens. Mycolactone was detectable in 92% and 77% of human samples (n=80) using cytotoxicity assays and mass spectrometry respectively. Antibiotic therapy was associated with a decline in tissue concentration of mycolactone in both human and murine-infected tissues which was paralleled by resolution of clinical lesions, reductions in bacteriological counts and restoration of local and systemic immune responses. Discussions/Conclusions: This study shows that mycolactone concentrations in tissues is closely associated with the presence of M. ulcerans and provides useful proof-of-concept data that mycolactone detection could potentially be used to monitor response to antibiotic therapy as well as for diagnosis of Buruli ulcer disease. The findings from the pilot study indicate that rifampicin combined with clarithromycin can replace rifampicin and streptomycin for the continuation phase after rifampicin-streptomycin treatment for 2 weeks without any apparent loss of efficacy. The implication is that a controlled trial of fully oral therapy using rifampicin and clarithromycin for 8 weeks (RC8) is justified.
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    Low seroprevalence of cryptococcal antigenaemia in patients with advanced HIV infection enrolling in an antiretroviral programme in Ghana
    (Tropical Medicine and International Health, 2011-01) Mamoojee, Yaasir; Shakoor, Shaid; Gorton, Rebecca L.; Sarfo, Fred Stephen; Phillips, Richard Odame; et. al
    objectives To determine the prevalence of cryptococcal antigenaemia in a clinic population with advanced HIV infection, with a view to giving antifungal therapy to those testing positive. methods Serum samples from adults with CD4 count <100 cells ⁄mm3 presenting to a large HIV clinic in Kumasi, Ghana, were tested retrospectively for cryptococcal antigenaemia using a latex agglutination assay, and clinical and demographic data extracted from case notes. results Of 92 samples tested, two were positive thus giving a prevalence of 2% (95% CI, 0–5.2%). conclusions The prevalence of cryptococcal antigenaemia in patients with advanced HIV infection enrolling in an antiretroviral programme appears to be low in Kumasi, suggesting that the value of routine testing of outpatients diagnosed with advanced HIV infection may be limited in this population.
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    Lower prevalence of Blastocystis sp. infections in HIV positive compared to HIV negative adults in Ghana
    (PLOS ONE, 2019-09-03) Phillips, Richard Odame; Cristanziano, Veronica Di; Alfonso, Rossella D´; Berrilli, Federica; Sarfo, Fred Stephen; et. al
    Background Sub-Saharan Africa is endemic for intestinal parasites and distinguished for the largest burden of HIV cases. Blastocystis sp. is one of the most common protists infecting humans but its role in human disease is still controversial. Aim of this study was to investigate the prevalence of Blastocystis sp. in HIV positive and negative adults in Ghana and its association with immune status and other risk factors. Methods 122 HIV positive outpatients and 70 HIV negative blood donors from the Komfo Anokye Teaching Hospital in Kumasi, Ghana, were included in the present study. Demographic, clinical and laboratory data were collected and HIV positive patients distinguished for CD4+ T cell count <200 cells/μl (n = 54) and >200 cells/μl (n = 68). A Blastocystis’s phylogenetic analysis was performed to determine sample subtype (ST). Results The prevalence of Blastocystis sp. in adult HIV positive individuals was lower than in HIV negative persons (6.6% vs. 20.0%, p = 0.008) and Blastocystis sp. ST1 was the most prevalent strain. Within HIV positive participants, the prevalence of Blastocystis sp. was lower in those individuals with CD4+ T cell count <200 cells/μl than in patients with higher CD4+ T cell count (1.9% vs. 10.3%, p = 0.076). Multiple regression analysis revealed that Blastocystis sp. was inversely associated with an obese Body Mass Index (BMI) in HIV negative persons (p = 0.040). Presence of Blastocystis sp. was correlated with higher CD4+ T cell count in HIV positive participants (p = 0.049). Conclusion It is largely reported that people living with HIV (PLHIV) in Africa are affected from parasite infections and that co-infections may adversely impact on their immune status, accelerating progress to AIDS and worsening gastrointestinal manifestations. Differently, in this study Blastocystis sp. was associated with a better immune status jointly with a healthy body weight while it seems to be reduced with the progression of HIV infection. This data agree with recent suggestions that Blastocystis sp. can represent a component of the healthy gut microbiota.