Jörg Nitschke - Academia.edu (original) (raw)

Papers by Jörg Nitschke

Research paper thumbnail of Implementation of a National Reference Laboratory for Buruli Ulcer Disease in Togo

PLoS Neglected Tropical Diseases, 2013

Background: In a previous study PCR analysis of clinical samples from suspected cases of Buruli u... more Background: In a previous study PCR analysis of clinical samples from suspected cases of Buruli ulcer disease (BUD) from Togo and external quality assurance (EQA) for local microscopy were conducted at an external reference laboratory in Germany. The relatively poor performance of local microscopy as well as effort and time associated with shipment of PCR samples necessitated the implementation of stringent EQA measures and availability of local laboratory capacity. This study describes the approach to implementation of a national BUD reference laboratory in Togo. Methodology: Large scale outreach activities accompanied by regular training programs for health care professionals were conducted in the regions ''Maritime'' and ''Central,'' standard operating procedures defined all processes in participating laboratories (regional, national and external reference laboratories) as well as the interaction between laboratories and partners in the field. Microscopy was conducted at regional level and slides were subjected to EQA at national and external reference laboratories. For PCR analysis, sample pairs were collected and subjected to a dry-reagent-based IS2404-PCR (DRB-PCR) at national level and standard IS2404 PCR followed by IS2404 qPCR analysis of negative samples at the external reference laboratory.

Research paper thumbnail of Effectiveness of Routine BCG Vaccination on Buruli Ulcer Disease: A Case-Control Study in the Democratic Republic of Congo, Ghana and Togo

PLoS neglected tropical diseases, 2015

The only available vaccine that could be potentially beneficial against mycobacterial diseases co... more The only available vaccine that could be potentially beneficial against mycobacterial diseases contains live attenuated bovine tuberculosis bacillus (Mycobacterium bovis) also called Bacillus Calmette-Guérin (BCG). Even though the BCG vaccine is still widely used, results on its effectiveness in preventing mycobacterial diseases are partially contradictory, especially regarding Buruli Ulcer Disease (BUD). The aim of this case-control study is to evaluate the possible protective effect of BCG vaccination on BUD. The present study was performed in three different countries and sites where BUD is endemic: in the Democratic Republic of the Congo, Ghana, and Togo from 2010 through 2013. The large study population was comprised of 401 cases with laboratory confirmed BUD and 826 controls, mostly family members or neighbors. After stratification by the three countries, two sexes and four age groups, no significant correlation was found between the presence of BCG scar and BUD status of indi...

Research paper thumbnail of Post-surgical assessment of excised tissue from patients with Buruli ulcer disease: progression of infection in macroscopically healthy tissue

Tropical Medicine and International Health, 2005

Research paper thumbnail of Excision of Pre-Ulcerative Forms of Buruli Ulcer Disease: A Curative Treatment

Infection, 2009

Background: Previous investigations have revealed that Mycobacterium ulcerans is extensively dist... more Background: Previous investigations have revealed that Mycobacterium ulcerans is extensively distributed spatially throughout ulcerative lesions, including in the margins of excised tissue. In contrast, bacilli in pre-ulcerative lesions are assumed to be concentrated in the center of the lesion. In order to assess the extent to which the surgical excision of pre-ulcerative lesions is capable of removing all infected tissue, we subjected the excision margins of pre-ulcerative lesions to laboratory analysis. Patients and Methods: Eleven patients with laboratoryconfirmed pre-ulcerative lesions were included in the study. The diameter of the lesion and excised tissue and the “surgical distance” between the border of the lesion and excision margin were measured. The entire excision margin was cut into segments and subjected to IS2404 PCR. Results: The results from the PCR analysis on the samples of excision margins were highly significantly associated with the surgical distance (p < 0.001). The margin samples of nodules were significantly more often PCR positive than the plaques (p = 0.025). The size of the lesion and the size of the excised tissue did not significantly influence the PCR results. Statistically, a surgical distance of more than 9 mm was found to reduce the risk of remaining infected tissue to less than 10%, that of 13 mm to reduce the risk to less than 5%, and that of 25 mm to reduce the risk to nearly 0%. Conclusion: The results of this study show that in preulcerative Buruli ulcer disease, bacilli may extend beyond the actual size of the lesion and that there is a strong correlation between the presence of M. ulcerans in the margin samples and the surgical distance. Excision with a surgical distance of 25 mm avoided the risk of remaining mycobacteria in this study. However, no recurrences occurred in the patients with M. ulcerans-positive excision margins. The need of postoperative antimycobacterial treatment in these patients remains to be determined.

Research paper thumbnail of Treatment Outcome of Patients with Buruli Ulcer Disease in Togo

PLOS Neglected Tropical Diseases, 2015

Following introduction of antimycobacterial treatment of Buruli ulcer disease (BUD), several clin... more Following introduction of antimycobacterial treatment of Buruli ulcer disease (BUD), several clinical studies evaluated treatment outcomes of BUD patients, in particular healing times, secondary lesions and functional limitations. Whereas recurrences were rarely observed, paradoxical reactions and functional limitations frequently occurred. Although systematic BUD control in Togo was established as early as 2007, treatment outcome has not been reviewed to date. Therefore, a pilot project on post-treatment follow-up of BUD patients in Togo aimed to evaluate treatment outcomes and to provide recommendations for optimization of treatment success. Out of 199 laboratory confirmed BUD patients, 129 could be enrolled in the study. The lesions of 109 patients (84.5%) were completely healed without any complications, 5 patients (3.9%) had secondary lesions and 15 patients (11.6%) had functional limitations. Edema, category III ulcers &amp;amp;amp;amp;amp;amp;gt;15cm, healing times &amp;amp;amp;amp;amp;amp;gt;180 days and a limitation of movement at time of discharge constituted the main risk factors significantly associated with BUD related functional limitations (P&amp;amp;amp;amp;amp;amp;lt;0.01). Review of all BUD related documentation revealed major shortcomings, in particular concerning medical records on adjuvant surgical and physiotherapeutic treatment. This study presents the first systematic analysis of treatment outcome of BUD patients from Togo. Median times to healing and the absence of recurrences were in line with findings reported by other investigators. The percentage of functional limitations of 11.6% was lower than in other studies, and edema, category III ulcers, healing time &amp;amp;amp;amp;amp;amp;gt;180 days and limitation of movement at discharge constituted the main risk factors for functional limitations in Togolese BUD patients. Standardized treatment plans, patient assessment and follow-up, as well as improved management of medical records are recommended to allow for intensified monitoring of disease progression and healing process, to facilitate implementation of therapeutic measures and to optimize treatment success.

Research paper thumbnail of A highly versatile microscope imaging technology platform for the multiplex real-time detection of biomolecules and autoimmune antibodies

Advances in biochemical engineering/biotechnology, 2013

The analysis of different biomolecules is of prime importance for life science research and medic... more The analysis of different biomolecules is of prime importance for life science research and medical diagnostics. Due to the discovery of new molecules and new emerging bioanalytical problems, there is an ongoing demand for a technology platform that provides a broad range of assays with a user-friendly flexibility and rapid adaptability to new applications. Here we describe a highly versatile microscopy platform, VideoScan, for the rapid and simultaneous analysis of various assay formats based on fluorescence microscopic detection. The technological design is equally suitable for assays in solution, microbead-based assays and cell pattern recognition. The multiplex real-time capability for tracking of changes under dynamic heating conditions makes it a useful tool for PCR applications and nucleic acid hybridization, enabling kinetic data acquisition impossible to obtain by other technologies using endpoint detection. The paper discusses the technological principle of the platform re...

Research paper thumbnail of Spontaneous Clearance of a Secondary Buruli Ulcer Lesion Emerging Ten Months after Completion of Chemotherapy—A Case Report from Togo

PLoS Neglected Tropical Diseases, 2012

Research paper thumbnail of Effectiveness of Routine BCG Vaccination on Buruli Ulcer Disease: A Case-Control Study in the Democratic Republic of Congo, Ghana and Togo

PLoS neglected tropical diseases, 2015

The only available vaccine that could be potentially beneficial against mycobacterial diseases co... more The only available vaccine that could be potentially beneficial against mycobacterial diseases contains live attenuated bovine tuberculosis bacillus (Mycobacterium bovis) also called Bacillus Calmette-Guérin (BCG). Even though the BCG vaccine is still widely used, results on its effectiveness in preventing mycobacterial diseases are partially contradictory, especially regarding Buruli Ulcer Disease (BUD). The aim of this case-control study is to evaluate the possible protective effect of BCG vaccination on BUD. The present study was performed in three different countries and sites where BUD is endemic: in the Democratic Republic of the Congo, Ghana, and Togo from 2010 through 2013. The large study population was comprised of 401 cases with laboratory confirmed BUD and 826 controls, mostly family members or neighbors. After stratification by the three countries, two sexes and four age groups, no significant correlation was found between the presence of BCG scar and BUD status of indi...

Research paper thumbnail of External quality assurance for the laboratory diagnosis of Buruli ulcer disease in Ghana

Tropical Medicine and International Health, 2006

Research paper thumbnail of A stepwise approach to the laboratory diagnosis of Buruli ulcer disease

Tropical Medicine and International Health, 2006

objective In view of technical and financial limitations in areas of endemicity, the current prac... more objective In view of technical and financial limitations in areas of endemicity, the current practice and recommendations for the laboratory diagnosis of Buruli ulcer disease (BUD) may have to be reconsidered. We reviewed diagnostic results in order to explore options for a modified, more practicable, cost-effective and timely approach to the laboratory diagnosis of BUD.

Research paper thumbnail of Molecular Determination of Rifampicin Resistance in Clinical Samples of Patients with Buruli Ulcer Disease: A Comparison of two Assays

Journal of Clinical Microbiology, 2014

Research paper thumbnail of Excision of Pre-Ulcerative Forms of Buruli Ulcer Disease: A Curative Treatment?

Infection, 2009

Mycobacterium ulcerans is extensively distributed spatially throughout ulcerative lesions, includ... more Mycobacterium ulcerans is extensively distributed spatially throughout ulcerative lesions, including in the margins of excised tissue. In contrast, bacilli in pre-ulcerative lesions are assumed to be concentrated in the center of the lesion. In order to assess the extent to which the surgical excision of pre-ulcerative lesions is capable of removing all infected tissue, we subjected the excision margins of pre-ulcerative lesions to laboratory analysis. Patients and Methods: Eleven patients with laboratoryconfirmed pre-ulcerative lesions were included in the study. The diameter of the lesion and excised tissue and the ''surgical distance'' between the border of the lesion and excision margin were measured. The entire excision margin was cut into segments and subjected to IS2404 PCR. Results: The results from the PCR analysis on the samples of excision margins were highly significantly associated with the surgical distance (p < 0.001). The margin samples of nodules were significantly more often PCR positive than the plaques (p = 0.025). The size of the lesion and the size of the excised tissue did not significantly influence the PCR results. Statistically, a surgical distance of more than 9 mm was found to reduce the risk of remaining infected tissue to less than 10%, that of 13 mm to reduce the risk to less than 5%, and that of 25 mm to reduce the risk to nearly 0%. Conclusion: The results of this study show that in preulcerative Buruli ulcer disease, bacilli may extend beyond the actual size of the lesion and that there is a strong correlation between the presence of M. ulcerans in the margin samples and the surgical distance. Excision with a surgical distance of 25 mm avoided the risk of remaining mycobacteria in this study. However, no recurrences occurred in the patients with M. ulcerans-positive excision margins. The need of postoperative antimycobacterial treatment in these patients remains to be determined.

Research paper thumbnail of Comparative Study of the Sensitivity of Different Diagnostic Methods for the Laboratory Diagnosis of Buruli Ulcer Disease

Clinical Infectious Diseases, 2009

Research paper thumbnail of Dry Reagent-Based Polymerase Chain Reaction Compared with Other Laboratory Methods Available for the Diagnosis of Buruli Ulcer Disease

Clinical Infectious Diseases, 2007

Research paper thumbnail of Adhesion of human and animal Escherichia coli in association with their virulence-associated genes and phylogenetic origin

Applied and Environmental Microbiology, 2013

Intestinal colonization is influenced by the ability of the bacterium to inhabit a niche, which i... more Intestinal colonization is influenced by the ability of the bacterium to inhabit a niche, which is based on the expression of colonization factors. Escherichia coli carries a broad range of virulence-associated genes (VAGs) which contribute to intestinal (inVAGs) and extraintestinal (exVAGs) infection. Moreover, initial evidence indicates that inVAGs and exVAGs support intestinal colonization. We developed new screening tools to genotypically and phenotypically characterize E. coli isolates originating in humans, domestic pigs, and 17 wild mammal and avian species. We analyzed 317 isolates for the occurrence of 44 VAGs using a novel multiplex PCR microbead assay (MPMA) and for adhesion to four epithelial cell lines using a new adhesion assay. We correlated data for the definition of new adhesion genes. inVAGs were identified only sporadically, particularly in roe deer (Capreolus capreolus) and the European hedgehog (Erinaceus europaeus). The prevalence of exVAGs depended on isolation from a specific host. Human uropathogenic E. coli isolates carried exVAGs with the highest prevalence, followed by badger (Meles meles) and roe deer isolates. Adhesion was found to be very diverse. Adhesion was specific to cells, host, and tissue, though it was also unspecific. Occurrence of the following VAGs was associated with a higher rate of adhesion to one or more cell lines: In summary, we established new screening methods which enabled us to characterize large numbers of E. coli isolates. We defined reservoirs for potential pathogenic E. coli. We also identified a very broad range of colonization strategies and defined potential new adhesion genes. a Virulence-associated genes (VAGs) which are involved in the E. coli pathogenesis of extraintestinal infections (exVAGs) and VAGs frequently detected in E. coli isolated from diarrheic hosts (inVAGs) were identified. Associated functions reported in the literature are included. ECoR, E. coli Reference Collection.

Research paper thumbnail of A Genotypic Approach for Detection, Identification, and Characterization of Drug Resistance in Mycobacterium ulcerans in Clinical Samples and Isolates from Ghana

American Journal of Tropical Medicine and Hygiene, 2010

Standardized antimycobacterial therapy is considered the treatment of choice for Buruli ulcer dis... more Standardized antimycobacterial therapy is considered the treatment of choice for Buruli ulcer disease. To assess the prevalence of drug resistance among clinical Mycobacterium ulcerans isolates in Ghana, we conducted a sequence-based approach to detect mutations associated with drug resistance. We subjected clinical samples to direct DNA sequencing of rpoB and rpsL genes and compared culture and whole-genome extracts regarding the efficiency of sequence analysis; 99.1% ( rpoB ) and 100% ( rpsL ) of the patients harbored M. ulcerans wild type. In one isolate (0.9%), a point mutation of the rpoB gene at codon Ser522 leading to an amino acid change was detected. Culture extracts yielded a significantly higher sequencing efficiency than whole-genome extracts. Our data suggest a low level of drug resistance in Ghana. However, mutations associated with drug resistance do occur and require monitoring. Improved techniques are necessary to enhance the efficiency of sequence analysis of whole-genome extracts.

Research paper thumbnail of Efficiency of Fine-Needle Aspiration Compared with Other Sampling Techniques for Laboratory Diagnosis of Buruli Ulcer Disease

Journal of Clinical Microbiology, 2010

In accordance with recent WHO recommendations, this study evaluates the sensitivities of PCR and ... more In accordance with recent WHO recommendations, this study evaluates the sensitivities of PCR and microscopy for fine-needle aspiration (FNA) versus techniques involving swabs and punch biopsy specimens and suggests that FNA can replace punch biopsies for nonulcerative lesions and may serve as an alternative for ulcerative lesions in cases where scarred edges prevent the collection of swabs.

Research paper thumbnail of Implementation of a National Reference Laboratory for Buruli Ulcer Disease in Togo

PLoS Neglected Tropical Diseases, 2013

Background: In a previous study PCR analysis of clinical samples from suspected cases of Buruli u... more Background: In a previous study PCR analysis of clinical samples from suspected cases of Buruli ulcer disease (BUD) from Togo and external quality assurance (EQA) for local microscopy were conducted at an external reference laboratory in Germany. The relatively poor performance of local microscopy as well as effort and time associated with shipment of PCR samples necessitated the implementation of stringent EQA measures and availability of local laboratory capacity. This study describes the approach to implementation of a national BUD reference laboratory in Togo. Methodology: Large scale outreach activities accompanied by regular training programs for health care professionals were conducted in the regions ''Maritime'' and ''Central,'' standard operating procedures defined all processes in participating laboratories (regional, national and external reference laboratories) as well as the interaction between laboratories and partners in the field. Microscopy was conducted at regional level and slides were subjected to EQA at national and external reference laboratories. For PCR analysis, sample pairs were collected and subjected to a dry-reagent-based IS2404-PCR (DRB-PCR) at national level and standard IS2404 PCR followed by IS2404 qPCR analysis of negative samples at the external reference laboratory.

Research paper thumbnail of Effectiveness of Routine BCG Vaccination on Buruli Ulcer Disease: A Case-Control Study in the Democratic Republic of Congo, Ghana and Togo

PLoS neglected tropical diseases, 2015

The only available vaccine that could be potentially beneficial against mycobacterial diseases co... more The only available vaccine that could be potentially beneficial against mycobacterial diseases contains live attenuated bovine tuberculosis bacillus (Mycobacterium bovis) also called Bacillus Calmette-Guérin (BCG). Even though the BCG vaccine is still widely used, results on its effectiveness in preventing mycobacterial diseases are partially contradictory, especially regarding Buruli Ulcer Disease (BUD). The aim of this case-control study is to evaluate the possible protective effect of BCG vaccination on BUD. The present study was performed in three different countries and sites where BUD is endemic: in the Democratic Republic of the Congo, Ghana, and Togo from 2010 through 2013. The large study population was comprised of 401 cases with laboratory confirmed BUD and 826 controls, mostly family members or neighbors. After stratification by the three countries, two sexes and four age groups, no significant correlation was found between the presence of BCG scar and BUD status of indi...

Research paper thumbnail of Post-surgical assessment of excised tissue from patients with Buruli ulcer disease: progression of infection in macroscopically healthy tissue

Tropical Medicine and International Health, 2005

Research paper thumbnail of Excision of Pre-Ulcerative Forms of Buruli Ulcer Disease: A Curative Treatment

Infection, 2009

Background: Previous investigations have revealed that Mycobacterium ulcerans is extensively dist... more Background: Previous investigations have revealed that Mycobacterium ulcerans is extensively distributed spatially throughout ulcerative lesions, including in the margins of excised tissue. In contrast, bacilli in pre-ulcerative lesions are assumed to be concentrated in the center of the lesion. In order to assess the extent to which the surgical excision of pre-ulcerative lesions is capable of removing all infected tissue, we subjected the excision margins of pre-ulcerative lesions to laboratory analysis. Patients and Methods: Eleven patients with laboratoryconfirmed pre-ulcerative lesions were included in the study. The diameter of the lesion and excised tissue and the “surgical distance” between the border of the lesion and excision margin were measured. The entire excision margin was cut into segments and subjected to IS2404 PCR. Results: The results from the PCR analysis on the samples of excision margins were highly significantly associated with the surgical distance (p < 0.001). The margin samples of nodules were significantly more often PCR positive than the plaques (p = 0.025). The size of the lesion and the size of the excised tissue did not significantly influence the PCR results. Statistically, a surgical distance of more than 9 mm was found to reduce the risk of remaining infected tissue to less than 10%, that of 13 mm to reduce the risk to less than 5%, and that of 25 mm to reduce the risk to nearly 0%. Conclusion: The results of this study show that in preulcerative Buruli ulcer disease, bacilli may extend beyond the actual size of the lesion and that there is a strong correlation between the presence of M. ulcerans in the margin samples and the surgical distance. Excision with a surgical distance of 25 mm avoided the risk of remaining mycobacteria in this study. However, no recurrences occurred in the patients with M. ulcerans-positive excision margins. The need of postoperative antimycobacterial treatment in these patients remains to be determined.

Research paper thumbnail of Treatment Outcome of Patients with Buruli Ulcer Disease in Togo

PLOS Neglected Tropical Diseases, 2015

Following introduction of antimycobacterial treatment of Buruli ulcer disease (BUD), several clin... more Following introduction of antimycobacterial treatment of Buruli ulcer disease (BUD), several clinical studies evaluated treatment outcomes of BUD patients, in particular healing times, secondary lesions and functional limitations. Whereas recurrences were rarely observed, paradoxical reactions and functional limitations frequently occurred. Although systematic BUD control in Togo was established as early as 2007, treatment outcome has not been reviewed to date. Therefore, a pilot project on post-treatment follow-up of BUD patients in Togo aimed to evaluate treatment outcomes and to provide recommendations for optimization of treatment success. Out of 199 laboratory confirmed BUD patients, 129 could be enrolled in the study. The lesions of 109 patients (84.5%) were completely healed without any complications, 5 patients (3.9%) had secondary lesions and 15 patients (11.6%) had functional limitations. Edema, category III ulcers &amp;amp;amp;amp;amp;amp;gt;15cm, healing times &amp;amp;amp;amp;amp;amp;gt;180 days and a limitation of movement at time of discharge constituted the main risk factors significantly associated with BUD related functional limitations (P&amp;amp;amp;amp;amp;amp;lt;0.01). Review of all BUD related documentation revealed major shortcomings, in particular concerning medical records on adjuvant surgical and physiotherapeutic treatment. This study presents the first systematic analysis of treatment outcome of BUD patients from Togo. Median times to healing and the absence of recurrences were in line with findings reported by other investigators. The percentage of functional limitations of 11.6% was lower than in other studies, and edema, category III ulcers, healing time &amp;amp;amp;amp;amp;amp;gt;180 days and limitation of movement at discharge constituted the main risk factors for functional limitations in Togolese BUD patients. Standardized treatment plans, patient assessment and follow-up, as well as improved management of medical records are recommended to allow for intensified monitoring of disease progression and healing process, to facilitate implementation of therapeutic measures and to optimize treatment success.

Research paper thumbnail of A highly versatile microscope imaging technology platform for the multiplex real-time detection of biomolecules and autoimmune antibodies

Advances in biochemical engineering/biotechnology, 2013

The analysis of different biomolecules is of prime importance for life science research and medic... more The analysis of different biomolecules is of prime importance for life science research and medical diagnostics. Due to the discovery of new molecules and new emerging bioanalytical problems, there is an ongoing demand for a technology platform that provides a broad range of assays with a user-friendly flexibility and rapid adaptability to new applications. Here we describe a highly versatile microscopy platform, VideoScan, for the rapid and simultaneous analysis of various assay formats based on fluorescence microscopic detection. The technological design is equally suitable for assays in solution, microbead-based assays and cell pattern recognition. The multiplex real-time capability for tracking of changes under dynamic heating conditions makes it a useful tool for PCR applications and nucleic acid hybridization, enabling kinetic data acquisition impossible to obtain by other technologies using endpoint detection. The paper discusses the technological principle of the platform re...

Research paper thumbnail of Spontaneous Clearance of a Secondary Buruli Ulcer Lesion Emerging Ten Months after Completion of Chemotherapy—A Case Report from Togo

PLoS Neglected Tropical Diseases, 2012

Research paper thumbnail of Effectiveness of Routine BCG Vaccination on Buruli Ulcer Disease: A Case-Control Study in the Democratic Republic of Congo, Ghana and Togo

PLoS neglected tropical diseases, 2015

The only available vaccine that could be potentially beneficial against mycobacterial diseases co... more The only available vaccine that could be potentially beneficial against mycobacterial diseases contains live attenuated bovine tuberculosis bacillus (Mycobacterium bovis) also called Bacillus Calmette-Guérin (BCG). Even though the BCG vaccine is still widely used, results on its effectiveness in preventing mycobacterial diseases are partially contradictory, especially regarding Buruli Ulcer Disease (BUD). The aim of this case-control study is to evaluate the possible protective effect of BCG vaccination on BUD. The present study was performed in three different countries and sites where BUD is endemic: in the Democratic Republic of the Congo, Ghana, and Togo from 2010 through 2013. The large study population was comprised of 401 cases with laboratory confirmed BUD and 826 controls, mostly family members or neighbors. After stratification by the three countries, two sexes and four age groups, no significant correlation was found between the presence of BCG scar and BUD status of indi...

Research paper thumbnail of External quality assurance for the laboratory diagnosis of Buruli ulcer disease in Ghana

Tropical Medicine and International Health, 2006

Research paper thumbnail of A stepwise approach to the laboratory diagnosis of Buruli ulcer disease

Tropical Medicine and International Health, 2006

objective In view of technical and financial limitations in areas of endemicity, the current prac... more objective In view of technical and financial limitations in areas of endemicity, the current practice and recommendations for the laboratory diagnosis of Buruli ulcer disease (BUD) may have to be reconsidered. We reviewed diagnostic results in order to explore options for a modified, more practicable, cost-effective and timely approach to the laboratory diagnosis of BUD.

Research paper thumbnail of Molecular Determination of Rifampicin Resistance in Clinical Samples of Patients with Buruli Ulcer Disease: A Comparison of two Assays

Journal of Clinical Microbiology, 2014

Research paper thumbnail of Excision of Pre-Ulcerative Forms of Buruli Ulcer Disease: A Curative Treatment?

Infection, 2009

Mycobacterium ulcerans is extensively distributed spatially throughout ulcerative lesions, includ... more Mycobacterium ulcerans is extensively distributed spatially throughout ulcerative lesions, including in the margins of excised tissue. In contrast, bacilli in pre-ulcerative lesions are assumed to be concentrated in the center of the lesion. In order to assess the extent to which the surgical excision of pre-ulcerative lesions is capable of removing all infected tissue, we subjected the excision margins of pre-ulcerative lesions to laboratory analysis. Patients and Methods: Eleven patients with laboratoryconfirmed pre-ulcerative lesions were included in the study. The diameter of the lesion and excised tissue and the ''surgical distance'' between the border of the lesion and excision margin were measured. The entire excision margin was cut into segments and subjected to IS2404 PCR. Results: The results from the PCR analysis on the samples of excision margins were highly significantly associated with the surgical distance (p < 0.001). The margin samples of nodules were significantly more often PCR positive than the plaques (p = 0.025). The size of the lesion and the size of the excised tissue did not significantly influence the PCR results. Statistically, a surgical distance of more than 9 mm was found to reduce the risk of remaining infected tissue to less than 10%, that of 13 mm to reduce the risk to less than 5%, and that of 25 mm to reduce the risk to nearly 0%. Conclusion: The results of this study show that in preulcerative Buruli ulcer disease, bacilli may extend beyond the actual size of the lesion and that there is a strong correlation between the presence of M. ulcerans in the margin samples and the surgical distance. Excision with a surgical distance of 25 mm avoided the risk of remaining mycobacteria in this study. However, no recurrences occurred in the patients with M. ulcerans-positive excision margins. The need of postoperative antimycobacterial treatment in these patients remains to be determined.

Research paper thumbnail of Comparative Study of the Sensitivity of Different Diagnostic Methods for the Laboratory Diagnosis of Buruli Ulcer Disease

Clinical Infectious Diseases, 2009

Research paper thumbnail of Dry Reagent-Based Polymerase Chain Reaction Compared with Other Laboratory Methods Available for the Diagnosis of Buruli Ulcer Disease

Clinical Infectious Diseases, 2007

Research paper thumbnail of Adhesion of human and animal Escherichia coli in association with their virulence-associated genes and phylogenetic origin

Applied and Environmental Microbiology, 2013

Intestinal colonization is influenced by the ability of the bacterium to inhabit a niche, which i... more Intestinal colonization is influenced by the ability of the bacterium to inhabit a niche, which is based on the expression of colonization factors. Escherichia coli carries a broad range of virulence-associated genes (VAGs) which contribute to intestinal (inVAGs) and extraintestinal (exVAGs) infection. Moreover, initial evidence indicates that inVAGs and exVAGs support intestinal colonization. We developed new screening tools to genotypically and phenotypically characterize E. coli isolates originating in humans, domestic pigs, and 17 wild mammal and avian species. We analyzed 317 isolates for the occurrence of 44 VAGs using a novel multiplex PCR microbead assay (MPMA) and for adhesion to four epithelial cell lines using a new adhesion assay. We correlated data for the definition of new adhesion genes. inVAGs were identified only sporadically, particularly in roe deer (Capreolus capreolus) and the European hedgehog (Erinaceus europaeus). The prevalence of exVAGs depended on isolation from a specific host. Human uropathogenic E. coli isolates carried exVAGs with the highest prevalence, followed by badger (Meles meles) and roe deer isolates. Adhesion was found to be very diverse. Adhesion was specific to cells, host, and tissue, though it was also unspecific. Occurrence of the following VAGs was associated with a higher rate of adhesion to one or more cell lines: In summary, we established new screening methods which enabled us to characterize large numbers of E. coli isolates. We defined reservoirs for potential pathogenic E. coli. We also identified a very broad range of colonization strategies and defined potential new adhesion genes. a Virulence-associated genes (VAGs) which are involved in the E. coli pathogenesis of extraintestinal infections (exVAGs) and VAGs frequently detected in E. coli isolated from diarrheic hosts (inVAGs) were identified. Associated functions reported in the literature are included. ECoR, E. coli Reference Collection.

Research paper thumbnail of A Genotypic Approach for Detection, Identification, and Characterization of Drug Resistance in Mycobacterium ulcerans in Clinical Samples and Isolates from Ghana

American Journal of Tropical Medicine and Hygiene, 2010

Standardized antimycobacterial therapy is considered the treatment of choice for Buruli ulcer dis... more Standardized antimycobacterial therapy is considered the treatment of choice for Buruli ulcer disease. To assess the prevalence of drug resistance among clinical Mycobacterium ulcerans isolates in Ghana, we conducted a sequence-based approach to detect mutations associated with drug resistance. We subjected clinical samples to direct DNA sequencing of rpoB and rpsL genes and compared culture and whole-genome extracts regarding the efficiency of sequence analysis; 99.1% ( rpoB ) and 100% ( rpsL ) of the patients harbored M. ulcerans wild type. In one isolate (0.9%), a point mutation of the rpoB gene at codon Ser522 leading to an amino acid change was detected. Culture extracts yielded a significantly higher sequencing efficiency than whole-genome extracts. Our data suggest a low level of drug resistance in Ghana. However, mutations associated with drug resistance do occur and require monitoring. Improved techniques are necessary to enhance the efficiency of sequence analysis of whole-genome extracts.

Research paper thumbnail of Efficiency of Fine-Needle Aspiration Compared with Other Sampling Techniques for Laboratory Diagnosis of Buruli Ulcer Disease

Journal of Clinical Microbiology, 2010

In accordance with recent WHO recommendations, this study evaluates the sensitivities of PCR and ... more In accordance with recent WHO recommendations, this study evaluates the sensitivities of PCR and microscopy for fine-needle aspiration (FNA) versus techniques involving swabs and punch biopsy specimens and suggests that FNA can replace punch biopsies for nonulcerative lesions and may serve as an alternative for ulcerative lesions in cases where scarred edges prevent the collection of swabs.