Antibiotic Resistance via Horizontal Gene Transfer in Commensal Microbiota of Healthy Individuals with Self-Medication Practices: A Questionnaire-Based and In Vitro Study
Keywords:
Antibiotic resistance, horizontal gene transfer, commensal microbiota, self-medication, multidrug resistance, resistomeAbstract
Background: Antibiotic resistance is a growing global health concern driven largely by inappropriate antibiotic use. Commensal microbiota of healthy individuals serve as an important reservoir of antibiotic resistance genes, which can be disseminated through horizontal gene transfer (HGT). Self-medication with antibiotics further accelerates this process by exerting selective pressure on microbial populations.
Aim: To assess antibiotic resistance mediated by horizontal gene transfer in commensal microbiota of healthy individuals with self-medication practices using a questionnaire-based survey and in vitro analysis.
Materials and Methods: This cross-sectional study was conducted over a defined period among healthy individuals attending Nandha Siddha Medical College and Hospital. A structured questionnaire was used to collect data on antibiotic self-medication practices, including frequency, indications, and sources of antibiotic use. Biological samples (stool and/or throat swabs) were collected for isolation of commensal bacteria and transported to CML Biotech Ltd, Angamaly, Kerala, for microbiological screening and analysis. Isolates were identified using standard microbiological methods and subjected to antibiotic susceptibility testing using the Kirby–Bauer disc diffusion method as per CLSI guidelines. Selected resistant strains were further analyzed for horizontal gene transfer using in vitro conjugation experiments..
Results: A significant proportion of participants reported self-medication with antibiotics. Commensal bacterial isolates from self-medicated individuals showed a higher prevalence of antibiotic resistance compared to non-users. Multidrug-resistant strains were frequently observed among isolates from the self-medication group. In vitro conjugation studies demonstrated successful transfer of resistance determinants between donor and recipient strains, confirming the role of horizontal gene transfer in resistance dissemination. Statistical analysis showed a significant association between self-medication practices and the presence of resistant isolates (p < 0.05).
Conclusion: The study highlights that self-medication with antibiotics contributes significantly to the emergence of antibiotic resistance in commensal microbiota. Horizontal gene transfer plays a crucial role in the dissemination of resistance genes, emphasizing the need for strict antibiotic stewardship and public awareness programs to curb indiscriminate antibiotic use.
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