Culture-based Characterization of Faecal Bacterial Isolates Following a Two-week Green Tea Intervention among Rivers State University Students, Port Harcourt, Nigeria

Green tea, produced from the leaves of Camellia sinensis, is consumed worldwide because of its reported antioxidant, anti-inflammatory, antimicrobial, and health-promoting properties. Emerging evidence suggests that dietary components, including green tea polyphenols, may influence the composition and activity of intestinal microorganisms. However, information on the culture-based bacterial profile of stool samples following green tea consumption among healthy Nigerian adults remains limited. This study aimed to evaluate changes in the culture-based profile of faecal bacterial isolates during a two-week green tea intervention among Rivers State University students, Port Harcourt, Nigeria. A prospective repeated-measures intervention study was conducted among 30 apparently healthy Rivers State University students residing in the university hostels. Each participant provided stool samples at three time points: baseline (before green tea consumption), after one week, and after two weeks of daily green tea intake, resulting in a total of 90 stool specimens. Stool samples were cultured on selective and differential bacteriological media, and bacterial isolates were identified using standard microbiological procedures, including colony morphology, Gram staining, and conventional biochemical tests. Data were analysed using descriptive statistics and presented as frequencies and percentages. The bacterial taxa recovered during the study included Escherichia coli, Staphylococcus aureus, Klebsiella spp., Enterobacter spp., and Salmonella spp. The frequency of recovery of Escherichia coli increased from 16.7% at baseline to 23.3% after one week and 30.0% after two weeks of the green tea intervention. Similar trends were observed for some of the other bacterial isolates. Conversely, the proportion of stool samples with no detectable bacterial growth on the culture media used decreased from 60.0% at baseline to 43.3% after one week and remained at 43.3% after two weeks of the intervention. The findings of this study suggest that a two-week green tea intervention was associated with changes in the frequency of recovery of selected cultivable faecal bacterial isolates among Rivers State University students. However, as the study relied solely on conventional culture-based methods, these findings should not be interpreted as evidence of comprehensive alterations in gut microbiota composition or of adverse effects on gut health. Furthermore, the relatively small sample size and short duration of the intervention may limit the generalisability of the findings. Future studies involving larger and more diverse populations, longer intervention periods, and molecular microbiome techniques are recommended to provide a more comprehensive understanding of the relationship between green tea consumption and the intestinal microbial community.