Probiotic Limosilactobacillus reuteri KUB-AC5 inhibits growth of clinical Salmonella enterica typhimurium isolates

Abstract

Salmonella enterica Typhimurium (STM) is a causative agent of an important foodborne disease, non-typhoidal salmonellosis (NTS) . Although NTS causes self-limiting acute diarrhea in a healthy host, it can result in a lifethreatening invasive NTS in immunocompromised hosts. An increase in multi-drug resistant (MDR) STM strains has been a major concern in the healthcare system and a search for alternative treatments has become imperative. Several probiotic strains have been extensively studied for their role against Salmonella. The Gram-positive bacterium Limosilactobacillus (Lactobacillus) reuteri KUB-AC5 (AC5) isolated from chicken gut has demonstrated an antagonistic effect to STM. However, the differences in STM strains could result in different outcomes of the AC5 intervention. In this study, we investigated the growth inhibitory effect of AC5 on five randomly selected MDR clinical STM strains (STMC) isolated from acute NTS patients admitted to Maharaj Nakorn Chiang Mai Hospital. All five STMCs (SMTC53, 78, 81, 101, and 107) exhibited MDR phenotypes. By using agar spot, cell-free supernatant diffusion agar and liquid medium co-culture assay, we found that AC5 can significantly inhibit the growth of all STMCs. Our study suggested that AC5 has the potential to be a probiotic intervention against STM infection in Thailand.