Isolation, Molecular Identification, and Biofilm Characterisation of Klebsiella pneumoniae from Clinical Specimens, with Evaluation of Probiotic Lactobacillus fermentum-Mediated Anti-Biofilm Activity

Authors

• Sophy PS, Professor, Dept of Microbiology, Muthoot College of Allied Health Sciences, Kozhencherry, Pathanamthitta, Kerala, IndiaFollow

Article Type

Article

Abstract

Background: Healthcare-associated infections caused by Klebsiella pneumoniae infection are increasingly associated with indwelling medical devices due to the organism's strong biofilm-forming ability, which enhances resistance to antibiotics and host immune responses. This study evaluated the biofilm-forming potential of clinical Klebsiella pneumoniae isolates and investigated the anti-biofilm activity of Lactobacillus fermentum under in vitro conditions. Methods: Fifteen clinical specimens, including catheter tips (n=6), sputum (n=5), and urine (n=4), were collected between September and December 2012. Isolates were identified using morphological and biochemical tests. Biofilm formation was assessed using the crystal violet microtiter plate assay. Molecular confirmation involved 16S rRNA gene sequencing and amplification of the treC biofilm-associated gene. Anti-biofilm and antimicrobial activities of L. fermentum whole culture and cell-free supernatant (CFS) were evaluated using crystal violet and agar well diffusion assays. Results: Seven isolates (46.7%) were confirmed as K. pneumoniae. Five isolates showed strong biofilm production, with isolate Kp03 demonstrating the highest biofilm density (OD₅₄₀ = 600). Sequencing confirmed Kp03 as K. pneumoniae subsp. pneumoniae with 99% identity, while the treC gene showed 100% identity with the NTUH-K2044 reference strain. Both L. fermentum whole culture and CFS reduced biofilm formation by more than 90% in all strong biofilm producers. Significant inhibition of planktonic growth was also observed, with inhibition zones ranging from 37–42 mm. Conclusion: The findings demonstrate that clinical K. pneumoniae isolates possess strong biofilm-forming capacity and that L. fermentum exhibits potent anti-biofilm and antibacterial activity, supporting its potential as a natural adjunct in preventing device-associated infections.

Keywords

Klebsiella pneumoniae, Biofilm formation, Lactobacillus fermentum, treC gene, 16S rDNA, Anti-biofilm activity, Nosocomial pathogens

Recommended Citation

PS, Sophy (2026) "Isolation, Molecular Identification, and Biofilm Characterisation of Klebsiella pneumoniae from Clinical Specimens, with Evaluation of Probiotic Lactobacillus fermentum-Mediated Anti-Biofilm Activity," Muthanna Medical Journal: Vol. 13: Iss. 2, Article 13.
Available at: https://muthmj.mu.edu.iq/journal/vol13/iss2/13

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.