Isolation and Identification of Mycobacterium in Soil and Water
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Date
2010
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Uva Wellassa University of Sri Lanka
Abstract
Mycobacteria were one of the first types of bacteria recognized to cause disease. The genus Mycobacterium is the only genus in the family Mycobacteriaceae. Mycobacteria are aerobic, non spore-forming, nonmotile, slightly curved or straight rods, which may branch. Colony morphology varies among the species, ranging from smooth to rough and from none pigmented to pigment. Non-tuberculous mycobacteria (NTM) comprise a variety of acid-fast bacilli species. They encompass, all mycobacterial species other than Mycobacterium tuberculosis complex (MTC) and Mycobacterium leprae. In Runyon's classification, mycobacteria, excluding those in the M. tuberculosis complex and noncultivable taxa (e.g., M. leprae), were divided into four groups based on growth rates and pigmentation properties. NTM are ubiquitous in nature and found as free living saprophytes in various environmental habitats especially in soil, dust, bio-films and water, including water from tanks, sewage, rivers and sea. NTM are generally found in the environment as free-living organisms, but many are also known as opportunistic human pathogens. In this study, the collected water and soil samples were processed and inoculated onto Lowenstein-Jensen media and the growth was observed in 28°C and 37°C in Dark ' & light conditions. Growth in different temperatures, culture conditions, acid fastness, colony morphology and color, were used in tentative identification to the species level. Mycobacterium species were widely distributed in soil and water and M.aichiense, M.smegmatis and M.fortuitum were common in both soil and water. Different Temperatures did not affect the growth of M.smegmatis, M.wolinsky, M. farcinogenes, M.fortuitum and M.poriferae while M.hiberniae, M.heidelbergense and M. kubicae produced pigments in light. M.poriferae a species previously isolated only from a marine sponge was able to isolate from a soil sample collected from coastal area which was affected by tsunami waves. M.intermedium grew on LJ and this is a specific species to hot tubs and hot showers.
Key words: Mycobacterium, Acid fast staining, Lowenstein-Jensen medium
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Keywords
Soil Science, Water Chemistry, Mycobacterium