Research Area

Lactic acid bacteria have been consumed for centuries in fermented foods. With regard to probiotics, L. casei Shirota (and its fermented milk product) has an unparalleled history of safe use, having been consumed by the general public on a very wide scale for more than 80 years, as well as being used by independent researchers and clinicians across a range of patients.

Across all of the studies published to date, there have been no reports of serious side effects or adverse events. Similarly, there has never been any report on the uptake of transferable antibiotic resistance genes by L. casei Shirota.

Study: Safety

Clinical safety in critically ill children  - Srinivasan et al. (2006) J Ped Gastroenterol Nutr 42:171-173.

Method: The objective of this study was to establish clinical safety of L. casei Shirota used as a probiotic in critically ill children. L. casei Shirota was administered three times a day at a dosage of 107 CFU/day via nasogastric, nasojejunal or gastrostomy enteral route, for five days to children admitted to a paediatric intensive care unit in the UK.  Safety was assessed by bacteriologic surveillance for the strain in surface swabs, endotracheal aspirates and blood, urine and sterile body fluid samples. 

Results: From the 28 patients with available safety data, there was no evidence of either colonisation or bacteraemia with L. casei Shirota from this testing. The L. casei Shirota was well tolerated with no apparent side effects or adverse reactions, supporting the conclusion that L. casei Shirota as a probiotic in critically ill children fed enterally appears safe. 


Enteral Nutrition Support

There are clinical trials and case reports on delivery of L. casei Shirota via enteral feeding tubes including nasogastric (NG), nasojejunal (NJ), and gastrostomy (Kanamori et al. 2010, Kanazawa et al. 2005, Shimizu et al. 2009, Srinivasan et al. 2006, Sugawara et al. 2006).

Although many of the case reports, intervention studies and meta-analyses that describe probiotic use in seriously ill patients report evidence of benefit, most also caution that more research is needed. 

The administration by naso-jejunal tube of high dosages of probiotics together with enteral nutrition containing high concentration of fermentable sugars, especially in patients with non-occlusive mesenteric ischemia, common in critically ill patients such as acute pancreatitis patients, should be discouraged (Besselink et al. 2008).



When considering to use probiotics for a specific patient where you may have safety concerns, it is important to consider:

• The quality and safety record of the particular probiotic

• The administration mode

• The patient’s condition

Critically Ill Patients

The L. casei Shirota strain has been used in clinical trials conducted in seriously ill patients with conditions such as alcoholic cirrhosis (Stadlbauer et al. 2008), severe systemic inflammatory response (Shimizu et al. 2009), on long-term mechanical ventilation (Hayakawa et al. 2012), elective liver donor patients (Eguchi et al. 2010), bladder, biliary and colorectal cancer patients (Kanazawa et al. 2005, Naito et al. 2008, Sugawara et al. 2006), very-low birth weight preterm infants (Braga et al. 2011) and critically ill children in intensive care (Srinivasan et al. 2006).  Case reports have also reported the use of L. casei Shirota in patients with severe respiratory distress (Kanamori et al. 2006b) and short bowel syndrome (Candy et al. 2001, Kanamori et al. 2001, Uchida et al. 2007).


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