In Vitro Antagonistic Activity of Probiotic Strains against Antibiotic-Resistant Klebsiella pneumoniae isolated from Preterm Infant Stools

Klebsiella pneumoniae is one of the most common opportunistic pathogens colonizing the preterm infant gut, and it is associated with neonatal infections. However, the use of antibiotics against infections can disrupt the gut microbiota and lead to emergence of antibiotic-resistant bacteria. Probiotics possess antimicrobial or antagonistic properties that play a key role in inhibiting pathogens. Probiotics (Bifidobacterium and Lactobacillus) could be a promising prophylactic or alternative therapy in aiding to curtail the spread of antibiotic-resistant bacteria in the gut and to overcome infection in preterm infants. This study aims to present findings on the antagonistic potential of probiotic strains against the isolated antibiotic-resistant Klebsiella pneumoniae from preterm infant stool samples. The antagonistic activity of these probiotic strains was assessed using cross-streak assay. Results demonstrated that Bifidobacterium longum subsp. infantis JCM 1222^T, and Lactiplantibacillus plantarum JCM11125 exhibited remarkable antagonistic effects on Klebsiella pneumoniae isolated from preterm infant stools, while the antagonistic activity exhibited by Bifidobacterium bifidum JCM 1255^T was weaker. Overall, our findings showed that selected probiotic strains could be a promising adjunct or preventive strategy for the management of Klebsiella pneumoniae infections in preterm infants, especially in settings where antibiotic resistance is prevalent. Nonetheless, future in vivo studies and clinical trials are essential to validate these findings, as well as to determine the optimal combinations, dosages, and safety profiles for their clinical applicability for neonatal use.