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Background Eumycetoma is a chronic subcutaneous granulomatous disease that is endemic in Sudan and other countries. It can be caused by eight different fungal orders. The gold standard diagnostic test is culture, however, culture-independent methods such as imaging, histopathological and molecular techniques can support diagnosis, especially in cases of negative cultures. Methods The amplicon-based internal transcribed spacer 2 metagenomic technique was used to study black grains isolated from 14 tissue biopsies from patients with mycetoma. Furthermore, mycological culture and surgical biopsy histopathological examinations of grains were performed. Results Madurella mycetomatis (n=5) and Falciformispora spp. (n=4) organisms were identified by culture and confirmed by metagenomics. Metagenomics recognised, at the species level, Falciformispora as Falciformispora tompkinsii (n=3) and Falciformispora senegalensis (n=1), while in culture-negative cases (n=5), Madurella mycetomatis (n=3), Falciformispora senegalensis (n=1) and Fusarium spp. (n=1) were identified. Interestingly, the metagenomics results showed a 'consortium' of different fungi in each sample, mainly Ascomycota phylum, including various species associated with eumycetoma. The microbial co-occurrence in eumycetoma showed the co-presence of Madurella with Trichoderma, Chaetomium , Malasseziales and Sordariales spp. while Falciformispora co-presented with Inocybe and Alternaria and was in mutual exclusion with Subramaniula, Aspergillus and Trichothecium. Conclusion Metagenomics provides new insights into the aetiology of eumycetoma in samples with negative culture and into the diversity and complexity of grains mycobiota, calling into question the accuracy of traditional culture for the identification of causative agents. [ABSTRACT FROM AUTHOR]

Background: Fluoroquinolone resistance is mediated by mutations in the quinolone-resistance determining region (QRDR) of the topoisomerase genes. Denaturing high performance liquid chromatography (DHPLC) was evaluated for detection of clinically important mutations in gyrB among Salmonella. Methods: Salmonella Typhi and S. Paratyphi A characterised for mutation in QRDR of gyrA, parC and parE were studied for mutation in gyrB by DHPLC and validated by sequencing. Results: The DHPLC analysis was able to resolve the test mutant from isolates with wild type gyrB and distinguished mutants from other mutant by peak profile and shift in retention time. Three sequence variants were detected at codon 464, and a novel mutation Ser→Thr was also detected. gyrB mutation was associated with non classical quinolone resistance (NALS-CIPDS) in 34 isolates of S. Typhi only and was distinct from classical quinolone resistance associated with gyrA mutations (NALR-CIPDS). Conclusions: DHPLC is effective for the detection of mutation and can reduce the need for sequencing to detect clinically significant gyrB mutations. [ABSTRACT FROM AUTHOR]

Background Non-typhoidal Salmonella infections are an important public health problem in sub-Saharan Africa, especially among children and HIV-seropositive patients in whom they may cause invasive disease. Methods In order to better understand the epidemiology of Salmonella infections in southern Africa we typed, using serotyping, phage typing and multilocus sequence typing, 167 non-typhoidal Salmonella strains isolated from human clinical specimens during 1995–2000. Results The most common serovars were Salmonella Typhimurium DT56/ST313, Salmonella Enteritidis PT4 and Salmonella Isangi ST216. Isolates of Salmonella Isangi showed a multidrug-resistant phenotype that was resistant to extended-spectrum cephalosporins. Twelve new sequence types and six new serotypes of Salmonella were identified. Conclusions Given the diversity detected in the study it seems likely that many new variants of S. enterica are extant in Zimbabwe and by implication across sub-Saharan Africa. We have demonstrated the presence in Zimbabwe of a multidrug-resistant strain of the serovar Salmonella Isangi and demonstrated the diversity of Salmonella circulating in one sub-Saharan African country. Further studies on the characteristics of Salmonella Isangi isolates from Zimbabwe, including plasmid typing and genotyping, are essential if effective control of the spread of this potential pathogen in sub-Saharan Africa is to be achieved. [ABSTRACT FROM AUTHOR]

DNA adenine methylation regulates virulence gene expression in certain bacteria, including Salmonella Typhimurium. The aim of this study was to investigate the involvement of DNA adenine methylase (Dam) methylation in the expression and secretion of the SPI-1 effector protein SopA. For this purpose, SopA–FLAG-tagged wild-type and dam strains of Salmonella Typhimurium were constructed. The expression and secretion of SopA were determined in bacterial culture and in intracellular bacteria recovered from infected HEp-2 epithelial cells. Bacterial culture supernatants and pellets were used to investigate secreted proteins and cell-associated proteins, respectively. Western blot and quantitative reverse transcriptase PCR analysis showed that the dam mutant expresses lower levels of SopA than the wild-type strain. Interestingly, the strain lacking Dam synthesizes SopA under nonpermissive conditions (28 °C). In addition, SopA secretion was drastically impaired in the dam mutant. In vivo experiments showed that the intracellular Salmonella dam mutant synthesizes SopA although in lower amounts than the wild-type strain. Taken together, our results suggest that Dam methylation modulates the expression and secretion of SopA in Salmonella Typhimurium. [ABSTRACT FROM AUTHOR]

Background Malaria transmission through blood transfusion is an accidental but preventable cause of malaria infection and is increasingly becoming a matter of concern for blood transfusion services. This systematic review was conducted to provide a summary of evidence about the prevalence of Plasmodium infection in asymptomatic blood donors and the effectiveness of screening methods used based on the available literature. Methods PRISMA guidelines were followed. Scopus, PubMed, Science Direct, and EMBASE were searched from 1982 to October 10, 2017. All peer-reviewed original research articles describing the prevalence of malaria parasitemia in blood donors with different diagnostic methods were included. The random-effects model was applied to assess the effects of heterogeneity among the selected studies. Incoherence and heterogeneity between studies were quantified by I 2 index and Cochran's Q test. Publication and population bias was assessed with funnel plots and Egger's regression asymmetry test. All statistical analyses were performed using Stata (version 2.7.2). Results Seventy-one studies from 21 countries, 5 continents, were included in the present systematic review. The median prevalence of malaria parasitemia among 984 975 asymptomatic healthy blood donors was 10.54%, 5.36%, and 0.38% by microscopy, molecular methods (polymerase chain reaction), and rapid diagnostic tests, respectively. The most commonly detected Plasmodium species was P. falciparum. Conclusions This systematic review demonstrates that compared with other transfusion-linked infections, that is, HIV, HCV, and HBV, transfusion-transmitted malaria is one of the most significant transfusion-associated infections especially in Sub-Saharan Africa. Future work must aim to understand the clinical significance of transfusion-transmitted malaria in malaria-endemic settings. [ABSTRACT FROM AUTHOR]