Prevalence of Colistin resistance in lactobacillus and streptococcus Thermophilus probiotics: case study of selected four yoghurts on Ugandan market
Namuluta, Gladys Esther
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The study was carried out to determine the prevalence colistin resistance phenotype in Lactobacillus and Streptococcus thermophilus probiotics from locally made yoghurt: case study of selected four yoghurts on Ugandan market. The probiotics used were Lactobacillus and Streptococcus thermophilus which are common useful bacteria used as probiotics in yoghurt and other foods as well. The two bacteria were isolated from four selected yoghurts on the Ugandan market using the Lactobacillus, Streptococcus Differential Medium (LS Differential Medium). Lactobacillus appeared as irregular, red colonies surrounded by a white opaque zone and Streptococcus thermophilus appeared round, red colonies surrounded by a clear zone. The susceptibility of Lactobacillus and Streptococcus thermophilus against colistin was tested using agar-well diffusion technique on Mueller-Hinton (MH) agar. Of the two bacteria tested, Lactobacillus turned out to be relatively more susceptible than Streptococcus thermophilus. The results showed that the means GYL, GYS, LYL, LYS, SYS are not significantly different because in all the cases there was no zone of inhibition subsequently implying that the probiotics: Lactobacillus and Streptococcus thermophilus have gained resistance against colistin antibiotic. Therefore, the probiotics: Lactobacillus and Streptococcus thermophilus from the four cases of yoghurts, only one yoghurt brand had some little resistance against colistin a last line antibiotic used to treat multidrug bacterial infections. In conclusion, the probiotics: Lactobacillus and Streptococcus thermophilus possessed resistance towards colistin antibiotic with the resistance more prevalent in Lactobacillus bacteria.