oa Southern African Journal of Epidemiology and Infection - Smokeless tobacco products on the South African market do not inhibit oral bacterial flora : a pilot study
Smokeless tobacco (ST) is commonly used by black South African women because of its perceived medicinal properties. This pilot study sought to evaluate the antibacterial effect of the local ST products on salivary microflora, using a growth medium. The five ST products tested included three traditional mixtures (brands A, B, C) and two popular industrially manufactured brands (Taxi and Ntsu). The following dilutions of supernatant solution of aqueous extracts of ST were prepared : 'pure' extract (100%), 75%, 50% and 25%. 50 µl of each ST extract of varying dilution was aseptically placed on sterilised grade 1 filter paper discs of diameter 2.5 cm, which was then placed on the saliva suspension in blood agar plates (BAPs) and incubated at 37°C aerobically and anaerobically for 72 hours. All BAPs, in duplicate, were then visually examined for inhibition zones after 24-, 48- and 72 hours. No bacterial inhibition zone was observed under aerobic or anaerobic conditions with any of the ST products tested, independent of time or the concentration of the ST suspension. However, a striking observation associated with both industrially manufactured brands and two traditional mixtures tested (A & B), was the presence of a zone of haemolysis within which bacterial colonies, identified as Gram-positive Bacillus species, was observed. This was only observed under aerobic conditions with and without saliva inoculums, and with 100% and 75% extract dilutions at 72 hour post-incubation. This preliminary finding of the presence of Bacillus spp with potential health implications, suggests the need for further investigations of bacterial activity in ST.
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