Applied Biology and Biochemistry Publications

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Browsing Applied Biology and Biochemistry Publications by Author "Chin’ombe, Nyasha"

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    Molecular identification of mycobacterium species of public health Importance in cattle in Zimbabwe by 16s rrna gene sequencing
    (BENTHAM OPEN, 2015) Padya, Leah; Chin’ombe, Nyasha; Magwenzi, Marcelyn; Mbanga, Joshua; Ruhanya, Vurayai; Nziramasanga, Pasipanodya
    Mycobacterium species are naturally found in the environment as well as in domestic animals such as cattle. So far, more than 150 species of Mycobacterium, some of which are pathogenic, have been identified. Laboratory isolation, detection and identification of Mycobacterium species are therefore critical if human and animal infections are to be controlled. The objective of this study was to identify Mycobacterium species isolated in cattle in Zimbabwe using 16S ribosomal RNA gene amplification and sequencing. A total of 134 cow dung samples were collected throughout Zimbabwe and mycobacteria were isolated by culture. Only 49 culture isolates that were found to be acid-fast bacilli positive by Ziehl-Neelsen staining. The 16S rRNA gene was successfully amplified by PCR in 41 (84%) of the samples. There was no amplification in 8 (16%) of the samples. Out of the 41 samples that showed amplification, 26 (63%) had strong PCR bands and were selected for DNA sequencing. Analysis of the DNA sequences showed that 7 (27%) belonged to Mycobacterium neoaurum, 6 (23%) belonged to Mycobacterium fortuitum, 3 (12%) to Mycobacterium goodii, 2 (1%) to Mycobacterium arupense, 2 (1%) to Mycobacterium peregrinum or M. septicum and 1 isolate (0.04%) to Mycobacterium elephantis. There were 5 (19%) isolates that were non-mycobacteria and identified as Gordonia terrae, a close relative of Mycobacterium. The study therefore provided a molecular basis for detection and identification of Mycobacterium species in animals and humans.
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    RpoB Gene-Based Characterization of Non-Tuberculous Mycobacteria in Zimbabwe
    (2017) Manjeese, Wadzanai; Muzividzi, Boniface; Mbanga, Joshua; Mufandaedza, Jonathan; Chin’ombe, Nyasha
    Aims: To characterize archived nontuberculous Mycobacteria (NTM) samples previously isolated from humans across Zimbabwe during the 2014 national tuberculosis survey. The rpoB gene of the isolates was targeted for characterization. Study Design: The research was an observational study where NTM samples previously isolated from Zimbabwean population were analysed by rpoB gene sequencing and phylogeny to identify NTM speciesPlace and Duration of Study: Department of Medical Microbiology, University of Zimbabwe between September 2015 and July 2016. Methodology: We obtained 99 NTM DNA samples from 963 NTM at NMRL, which we characterised using rpoB gene analysis after PCR amplification. The amplicons were sequenced and bioinformatics tools were used for speciation. The rpoB gene of DNA extracts from the NTM was amplified and the sequences were analysed using bioinformatics tools to identify the NTM to species level. Results: From the 99 NTM isolates, 40 were sequenced and analyzed. The NTM were identified as belonging to 13 species. The species were M. palustre (14.8%), M. aroisense (29.6%), M. parascrofulaceum (3.7%), M. arupense (7.4%), M. asiaticum (3.7%), M. malmoense (3.7%), M. lacus (3.7%), M. avium (7.4%), M. nonchromogenicum (3.7%), M. gordonae (3.7%), M. aromaticivorans (3.7%), M. novocastrense (3.7%), M. bourgelatii (3.7%). One sample (3.7%) belonged to Mtb complex species (3.7%) and another one (3.7%) was closely related to S. oryzae. The most common species belonged to M. aroisense and M. palustre. The species showed a high degree of rpoB sequence diversity. Sequence analysis of the rifampicin resistance determining region (RRDR) showed the existence of only silent mutations. Conclusion: Species of NTM from Zimbabwe showed a high degree of rpoB gene sequence diversity. This characteristic feature can therefore be used in diagnosis and identification of NTM in clinical specimens