Investigation of Oral Bacterial Population in Tobacco Chewers and Healthy Individuals

Objectives The study aimed to isolate and identify bacterial species from the oral cavities of healthy individuals and tobacco chewers. A comparative evaluation of the bacterial colonies and species present in both groups was then conducted to assess the impact of tobacco chewing on the oral microbiome. Material and Methods A total of 90 oral swab samples were collected, including 50 from tobacco chewers and 40 from non-chewers. The samples were transported aseptically in peptone water and incubated. After 24 h, the samples were streaked onto nutrient agar, MacConkey agar, and blood agar and incubated at 37°C. The resulting colonies were observed, and Gram staining was performed. Bacterial isolates were identified using biochemical tests, including the citrate utilization test, indole test, urease test, and triple sugar iron (TSI) test. For molecular identification, DNA was isolated from pure cultures and subjected to PCR using 16S rRNA gene-specific forward and reverse primers. The PCR products were sent to Eurofins Genomics India Pvt. Ltd. for sequencing. Results The results indicate alterations in the oral microbial flora of tobacco chewers compared with non-chewers. Streptococcus anginosus KCOM3315 and Streptococcus anginosus 4956 were detected in both tobacco chewers and non-chewers and are considered potentially pathogenic. In contrast, Pantoea agglomerans was detected only in tobacco chewers and was absent in non-chewers. Pantoea agglomerans is primarily a plant-associated bacterium but can cause opportunistic infections in humans. Rothia dentocariosa and Staphylococcus epidermidis , which are considered commensal bacteria, were detected in both tobacco chewers and non-chewers. Conclusion The percentage of pathogenic bacteria was higher in tobacco chewers compared with non-chewers. In contrast, the percentage of commensal bacteria was lower in tobacco chewers than in non-chewers.