The Antimicrobial Effect of Lactobacillus casei against Klebsiella pneumoniae and Escherichia coli Isolated from Urinary Samples

Background & Objectives: Urinary tract infection (UTI) is a serious issue affecting both men and women resulting from the invasion of microbial agents into the urinary system. This study aimed to investigate the antimicrobial activity of Lactobacillus casei (L. casei) against Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli) isolated from UTI. Materials & Methods: In this study, 100 urine specimens were obtained from medical laboratories in western Tehran. E. coli and K. pneumoniae isolates were identified and subsequently confirmed using polymerase chain reaction (PCR). Antibiotic susceptibility patterns were determined using the disk diffusion method. The antimicrobial activity of L. casei against these strains (four multidrug-resistant isolates from each species) was then evaluated using the agar well diffusion method. Results: From 100 urine specimens, 76 E. coli and 14 K. pneumoniae isolates were identified. Antimicrobial susceptibility testing revealed that imipenem and nitrofurantoin were the most effective antibiotics against E. coli, while amikacin demonstrated the highest efficacy against K. pneumoniae. In the agar well diffusion assay, L. casei generated growth inhibition zones measuring 19.8 mm ± 3 for E. coli and 20.3 mm ± 4 for K. pneumoniae. Conclusions: Lactobacillus casei demonstrates notable antimicrobial efficacy against both E. coli and K. pneumoniae, suggesting its potential as an alternative therapeutic option for UTIs.

The Antimicrobial Effect of Lactobacillus casei against Klebsiella pneumoniae and Escherichia coli Isolated from Urinary Samples Keywords:

Lactobacillus casei , Escherichia coli , Klebsiella pneumoniae , Urinary Tract Infection , Probiotics