Susceptibility Profiles of Mycobacterium ulcerans

Background. Drug resistance is a major challenge in antibiotic chemotherapy. Assessing resistance profiles of pathogens constitutes an essential surveillance tool in the epidemiology and control of infectious diseases, including Buruli ulcer (BU) disease. With the successful definitive management of BU using rifampicin and streptomycin, little attention had been paid to monitoring emergence of resistant Mycobacterium ulcerans (M. ulcerans) isolates in endemic communities. This study investigated the susceptibility profiles of M. ulcerans isolates from two BU endemic areas in Ghana to streptomycin and rifampicin. Methods. The antibiotic susceptibility of seventy (70) M. ulcerans isolates to rifampicin and streptomycin was determined simultaneously at critical concentrations of 40 µg/mL and 4 µg/mL, respectively, by the Canetti proportion method. Results. Resistance to rifampicin was observed for 12 (17.1%) M. ulcerans isolates tested, whilst 2 (2.9%) showed resistance to streptomycin. None of the isolates tested showed dual resistance to both rifampicin and streptomycin. Conclusion. Outcomes from this study may not be reflective of all BU endemic communities; it, however, provides information on the resistance status of the isolates, which is useful for monitoring of M. ulcerans, as well as BU disease surveillance and control

Evaluating the yaws diagnostic gap: A survey to determine the capacity of and barriers to improving diagnostics in all yaws-endemic countries

BACKGROUND: Yaws, caused by Treponema pallidum subsp. pertenue, is a skin neglected tropical disease. It is targeted for eradication by 2030, primarily using mass drug administration (MDA) with azithromycin. Traditionally, diagnosis of yaws has relied on clinical examination and serological testing. However, these approaches have poor diagnostic performance. To achieve eradication, more accurate diagnostics are required to determine whether MDA should be initiated or continued as well as for post-elimination surveillance. Molecular tools will be crucial for detecting antimicrobial resistant cases, which have the potential to derail eradication efforts. In order to determine the feasibility of introducing novel, more accurate, diagnostics for yaws surveillance purposes, it is necessary to understand current in-country diagnostic capacity. This study therefore aimed to understand the current capacity of, and challenges to, improving diagnostics for yaws in all yaws-endemic countries worldwide. METHODOLOGY/ PRINCIPLE FINDINGS: An online survey was sent to all 15 yaws-endemic countries in July 2021. The survey asked about past prevalence estimates, the availability of different diagnostic tools, and perceived barriers to enhancing capacity. Fourteen countries responded to the survey, four of which did not have a current National Policy for yaws eradication in place. Over 95% of reported that yaws cases from the past five years had not been confirmed with serological or molecular tools, largely due to the limited supply of rapid serological tests. Only four countries reported having operational laboratories for molecular yaws diagnosis, with only one of these having a validated assay to detect azithromycin resistance. CONCLUSIONS AND SIGNIFICANCE: This study highlights the diagnostic capacity constraints across all respondent countries. Countries are in need of access to a sustainable supply of serological tests, and development of molecular testing facilities. Sufficient sustainable funding should be made available to ensure that appropriate diagnostic tools are available and utilised

Susceptibility Profiles of Mycobacterium ulcerans Isolates to Streptomycin and Rifampicin in Two Districts of the Eastern Region of Ghana

Background. Drug resistance is a major challenge in antibiotic chemotherapy. Assessing resistance profiles of pathogens constitutes an essential surveillance tool in the epidemiology and control of infectious diseases, including Buruli ulcer (BU) disease. With the successful definitive management of BU using rifampicin and streptomycin, little attention had been paid to monitoring emergence of resistant Mycobacterium ulcerans (M. ulcerans) isolates in endemic communities. This study investigated the susceptibility profiles of M. ulcerans isolates from two BU endemic areas in Ghana to streptomycin and rifampicin. Methods. The antibiotic susceptibility of seventy (70) M. ulcerans isolates to rifampicin and streptomycin was determined simultaneously at critical concentrations of 40 g/mL and 4 g/mL, respectively, by the Canetti proportion method. Results. Resistance to rifampicin was observed for 12 (17.1%) M. ulcerans isolates tested, whilst 2 (2.9%) showed resistance to streptomycin. None of the isolates tested showed dual resistance to both rifampicin and streptomycin. Conclusion. Outcomes from this study may not be reflective of all BU endemic communities; it, however, provides information on the resistance status of the isolates, which is useful for monitoring of M. ulcerans, as well as BU disease surveillance and control

Map of Ghana indicating the region and communities from which the 19 BU patients colonized with <i>S. aureus</i> originated.

<p>Map of Ghana indicating the region and communities from which the 19 BU patients colonized with <i>S. aureus</i> originated.</p

Antibiotic resistances of the 91 <i>S. aureus</i> study isolates.

<p>For details on the antibiotic resistances of the respective study isolates, please see <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003421#pntd.0003421.s001" target="_blank">S1 Table</a> in the Supporting Information.</p><p>Antibiotic resistances of the 91 <i>S. aureus</i> study isolates.</p

<i>spa</i>-types of 91 <i>S. aureus</i> isolates from the anterior nares and wounds of 19 BU patients.

<p><i>spa</i>-types of 91 <i>S. aureus</i> isolates from the anterior nares and wounds of 19 BU patients.</p

Genetic Diversity of <i>Staphylococcus aureus</i> in Buruli Ulcer

<div><p>Background</p><p>Buruli ulcer (BU) is a necrotizing skin disease caused by Mycobacterium ulcerans. Previous studies have shown that wounds of BU patients are colonized with M. ulcerans and several other microorganisms, including <i>Staphylococcus aureus</i>, which may interfere with wound healing. The present study was therefore aimed at investigating the diversity and topography of <i>S. aureus</i> colonizing BU patients during treatment.</p><p>Methodology</p><p>We investigated the presence, diversity, and spatio-temporal distribution of <i>S. aureus</i> in 30 confirmed BU patients from Ghana during treatment. <i>S. aureus</i> was isolated from nose and wound swabs, and by replica plating of wound dressings collected bi-weekly from patients. <i>S. aureus</i> isolates were characterized by multiple-locus variable number tandem repeat fingerprinting (MLVF) and spa-typing, and antibiotic susceptibility was tested.</p><p>Principal Findings</p><p>Nineteen (63%) of the 30 BU patients tested positive for <i>S. aureus</i> at least once during the sampling period, yielding 407 <i>S. aureus</i> isolates. Detailed analysis of 91 isolates grouped these isolates into 13 MLVF clusters and 13 spa-types. Five (26%) <i>S. aureus</i>-positive BU patients carried the same <i>S. aureus</i> genotype in their anterior nares and wounds. <i>S. aureus</i> isolates from the wounds of seven (37%) patients were distributed over two different MLVF clusters. Wounds of three (16%) patients were colonized with isolates belonging to two different genotypes at the same time, and five (26%) patients were colonized with different <i>S. aureus</i> types over time. Five (17%) of the 30 included BU patients tested positive for methicillin-resistant <i>S. aureus</i> (MRSA).</p><p>Conclusion/Significance</p><p>The present study showed that the wounds of many BU patients were contaminated with <i>S. aureus</i>, and that many BU patients from the different communities carried the same <i>S. aureus</i> genotype during treatment. This calls for improved wound care and hygiene.</p></div

<i>spa</i>-types of 91 <i>S. aureus</i> isolates from the anterior nares and wounds of 19 BU patients.

<p><i>spa</i>-types of 91 <i>S. aureus</i> isolates from the anterior nares and wounds of 19 BU patients.</p

<i>S. aureus</i> wound topography in BU patients.

<p>Used dressings from wounds of BU patients were replica-plated onto CLED agar plates, and <i>S. aureus</i> colonies thus obtained were typed by MLVF. <i>S. aureus</i> colonies belonging to different MLVF clusters are shown in different colors: cluster A, red circles; cluster D, blue circles; cluster F, yellow circles; cluster H, green circle and cluster L, purple circles. (A) Replica plate of a wound dressing collected from patient 7 at time point t8 with <i>S. aureus</i> colonies belonging to clusters A and D, (B) Replica plate of a wound dressing collected from patient 7 at time t5 with <i>S. aureus</i> colonies belonging to clusters F and H. (C) Replica plate of a wound dressing collected from patient 22 at time t6 with <i>S. aureus</i> colonies belonging to clusters A and L.</p