Genetic study of bacterial species isolated from local dairy products in some Iraqi cities

Background: In recent years, there has been a growing global interest in diets containing microorganisms beneficial to human known as probiotics, which are part of a class of strains of lactic acid bacteria that have many health benefits. The goal of this study is to find out what kinds of bacteria are found in dairy products that are sold in local markets in some city Iraq. Methods: Two hundred samples of yoghurt have been collected from four local cities (Diwaniyah, Najaf, Karbala, and Babylon). 1 ml of yoghurt samples were spread on a Lactobacillus MRS medium, which was incubated under anaerobic conditions using a candle jar at 37ᵒC for 48 h. Isolated species were diagnosed based on phenotypic and microscopic characteristics, and the DNA of the isolates was extracted and partly characterized by molecular methods . Results: As 200 bacterial isolates were isolated and their identities were identified microscopically, all the isolated species were positive for the Gram stain. It took DNA sequencing to identify eight different bacterial genera. These eight were (Brevibacillus sp.,Lactobacillus delbrueckii subsp.,lactis, Bacillus paralicheniformis, Bacillus badius, Paenibacillus lautus, Lacticaseibacillus rhamnosus, Bacillus licheniformis, and Bacillus spp.) .Isolated from local dairy products traded in the local markets after the diagnosis was confirmed molecularly and based on the 16S rRNA gene and based on the data of the International Genetic Bank (NCBI-Gen bank). Conclusions: Among the bacterial species that have been diagnosed are L. delbrueckii subsp. lactis and L. rhamnosus, which play a very important role as probiotics.