Volume 13 (ISTJN)

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Browsing Volume 13 (ISTJN) by Author "Kaimoyo, E."

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    Molecular characterization of culturable thermophilic prokaryotes from Chinyunyu hot spring in central Zambia
    (University of Namibia, 2019) Kalumbilo, M.P.; Kaimoyo, E.; Phiri, J.
    Hot springs are among some of the naturally-occurring extreme environments that have generated considerable interest in researchers worldwide. Thermophilic prokaryotes present in hot spring habitats are considered valuable sources for biotechnological products including thermally-stable enzymes applied in many research and manufacturing process. Despite the numerous hot springs in Zambia, there is limited information on the diversity of thermophilic prokaryotes in these places. In this study, characterization of thermophilic prokaryotes isolated from Chinyunyu hot spring in Lusaka province, Zambia was conducted using phenotypic and molecular-methods. The recorded temperature of the hot spring at the time of sampling was 60 C and the pH was 9.0 indicating alkaline environment. A total of 13 phenotypically distinct isolates were identified on nutrient agar medium at 55 C and pH 7.0. All isolates were Gram-positive, rod-shaped cells. Their genomic DNA was PCR-amplified using 16S rRNA primers and sequenced using the Big Dye Terminator v3.1 cycle sequencing kit on the ABI Prism 3130xl Genetic Analyzer (Life Technologies Corp). Amplicon sequences were analyzed using Basic Local Alignment Search Tool (BLAST) and revealed that all isolates belonged to the bacterial phylum Firmicutes. Seven isolates were affiliated to the genus Anoxybacillus and six were affiliated to the genus Bacillus. The study revealed that Chinyunyu hot spring harbours genetically diverse thermophilic prokaryotes which could be amenable to further studies to exploit the hot spring microbiome for its biotechnological potential.
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    Molecular differentiation of rifampicin and isoniazid drug resistant Mycobacterium tuberculosis complex isolated from selected parts of Zambia
    (University of Namibia, 2019) Kapona, O.; Kaimoyo, E.; Katongo, C.
    The most prevalent Mycobacterium species in the Mycobacterium tuberculosis complex and frequency of mutations in the genes conferring resistance to rifampicin and isoniazid in Zambia have until now remained unknown. This study sought to differentiate the isolates of Mycobacterium tuberculosis complex (MTBC) using genetic regions cfp32, RD9 and RD12 and determine the prevalence of resistance-associated mutations in two specific resistance marker genes (rpoB and katG) and the inhA promoter region of M. tuberculosis isolated at the University Teaching Hospital Tuberculosis Laboratory between January 2013 and June 2014. Genomic DNA was extracted from 40 isolates and amplified by multiplex PCR for regions cfp32, RD9 and RD12 and single PCRs for three drugresistance conferring loci (katG, rpoB and inhA). All isolates were positive for the three regions typical of M. tuberculosis. Seventy-five percent had the S315T mutation in katG gene and one had mutations in the inhA promoter and rpoB in addition to the katG 315 mutation. The S450L (48.7%) and H445Y (20.5%) mutations were the most frequently observed mutations in the rpoB gene while rifampicin mono-resistance was observed in 2.6% of the rifampicin-resistant isolates. Molecular diagnostic tests based on detecting these predominant mutations could be useful for the rapid detection of multi drug resistant tuberculosis in Eastern, Lusaka, Western parts of Zambia and TB patients in these regions can be treated with the standard first line tuberculosis drugs.