The Impact of Lactobacillus plantarum Supernatant and Colistin on Growth, Surface Hydrophobicity, Exopolysaccharide Production, and Biofilm Formation in Klebsiella pneumoniae

Subject Areas : microbiology

Fatemeh Noorbakhsh ^{1 *} , Faezeh Ebadi ² , Akram sadat Tabatabaee Bafroee ³

1 - Department of Microbiology, VP.C., Islamic Azad university,Varamin-Pishva, Iran
2 - Department of Biology, ET.C., Islamic Azad University, Tehran, Iran
3 - Department of Biology, ET.C., Islamic Azad University, Tehran, Iran

Received: 2025-09-20 Accepted : 2025-10-18 Published : 2025-09-09

Keywords: Klebsiella pneumoniae, Lactobacillus plantarum, Colistin, Biofilm, Synergistic effect, CFS, EPS,

Abstract :

Introduction: Klebsiella pneumoniae is a significant bacterial pathogen, notable for its antibiotic resistance and ability to form biofilms. This study aimed to investigate the effect of Lactobacillus plantarum supernatant and colistin on Klebsiella pneumoniae, focusing on antimicrobial activity and biofilm inhibition.

Materials and Methods: In this study, 100 clinical samples were collected from patients, and 20 isolates of Klebsiella pneumoniae were identified using biochemical tests. Antibiotic susceptibility was determined by the antibiogram method. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for colistin and Lactobacillus plantarum supernatant were evaluated. The Fractional Inhibitory Concentration (FIC) index, anti-biofilm activity, biofilm dispersion, cell surface hydrophobicity, and exopolysaccharide production under treatment with colistin and the supernatant were also assessed.

Results: Colistin demonstrated higher antimicrobial activity compared to Lactobacillus plantarum supernatant. The FIC index ranged from 0.517 to 0.827, indicating an additive effect. Biofilm formation was significantly reduced with colistin treatment compared to supernatant treatment (p < 0.05). Biofilm dispersion increased with the combined treatment compared to individual treatments. Cell surface hydrophobicity decreased from 62% (control) to 34% with the combined treatment. Exopolysaccharide production decreased from 473 mg (control) to 231 mg per 100 ml with the combined treatment.

Conclusion: The combination of Lactobacillus plantarum supernatant and colistin demonstrated enhanced antimicrobial efficacy and control of biofilm formation against Klebsiella pneumoniae. This synergistic approach could potentially lead to a reduction in antibiotic dosage and improved treatment outcomes for Klebsiella pneumoniae infections.

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