Recovery of Lactobacillus casei strain Shirota (LcS) from faeces with 14 days of fermented milk supplementation in healthy Australian adults.

Abstract

A key measure for classifying bacteria as a probiotic is the ability to survive gastric transport and be recoverable in faeces. The aim of this study was to determine whether Lactobacillus casei strain Shirota (LcS) could be recovered in the faeces of healthy young Australian adults following ingestion of a fermented milk drink. A cohort of 25 healthy individuals (male/female: 14/11; age: 29.3±6.6 years; BMI: 25.3±2.7 kg/m2, mean±SD) ingested one 65 ml bottle of fermented milk containing 6.5×109 LcS live cells daily for 14 days. Participants provided a faecal sample at day 0, day 7 (mid-supplementation), day 14 (end of supplementation) and 14 days after cessation of the supplement (day 28) for assessment of the number of viable LcS via microbial culture on selective media with confirmation using a colony-direct polymerase chain reaction and species-specific primers. The supplement was well tolerated by participants. No LcS colonies were recovered from participants prior to ingestion of the fermented milk drink. All participants had recoverable LcS colonies at day 7 and day 14, with a mean recovery of 6.5±1.1 and 6.4±1.1 log10 CFU/g of faeces (mean±SD) at each time point respectively. LcS was detectable in only one sample at 14 days following the cessation of supplementation. Live LcS is recoverable in faeces from healthy Australian adults following daily ingestion of a fermented milk drink.