Lactobacillus Beverage Confirmed to Reduce Fever Brought on by Acute Gastroenteritis Caused by Norovirus Infection

- Expected to Prevent Mass Infections in Gastroenteritis Rest Home Outbreak -

10 May, 2011, 00:00 ET from Juntendo University

TOKYO, May 10, 2011 /PRNewswire/ -- The Laboratory Department for Probiotics Research at the Juntendo University Graduate School of Medicine (NAGATA Satoru, YAMASHIRO Yuichiro et al.) studied supplementation of probiotic fermented milk containing Lactobacillus casei strain Shirota (LcS) in elderly individuals living at a nursing home and confirmed reduced fever associated with acute norovirus gastroenteritis.

Analysis of fecal flora demonstrated that daily intake of LcS-fermented milk increased useful bacteria (bifidobacteria, lactobacillus), reduced harmful bacteria (coliform group), and increased short chain fatty acids, suggesting that an improved intestinal flora and environment contributed to alleviation of the gastroenteritis symptom.

Norovirus is known to be a leading cause of acute infectious gastroenteritis, which can occasionally increase in the severity, especially in elderly individuals with compromised immune systems at risk of developing dehydration. There has recently been an epidemic of the mass infection at facilities for the elderly. Prevention of such infections is a challenge.

Little data are available concerning the effects of probiotics such as lactobacillus, and no report is available on norovirus as far as we know.

Our findings indicate that probiotic supplementation may serve as an effective means of prevention from infectious gastroenteritis including those due to norovirus at facilities where elderly individuals with compromised immune systems live in groups.

The findings were published on April 27, 2011, in the online version of the British Journal of Nutrition, a scientific journal.

1. Background

Norovirus is known to be a major cause of acute infectious gastroenteritis. Norovirus infection is transmitted orally via fingers and contaminated foods, and causes vomiting, diarrhea and/or abdominal pain when it proliferates in the intestine. It may be mild with a quick recovery for healthy individuals, but can become severe in infants or the elderly with compromised immune systems, and even lead to death as a result of aspiration pneumonia following vomiting or severe dehydration. Particularly at nursing homes, where elderly individuals with compromised immune systems live communally, risk management against infectious diseases is critical. It is, however, very difficult to fully control infection, and thus minimizing harm from infection is challenging.

Our research group studied the efficacy in prevention from norovirus infection by means of intake of lactobacillus (Lactobacillus casei strain Shirota ; LcS), which has been known to protect against infection and have immune-regulatory properties.

2. Study Details

The study was conducted in 77 elderly individuals living at a nursing home (average age 84). The subjects were divided into two groups: one was an intake group (39) and the other a non-intake group (38). The intake group was given one LcS fermented milk serving (one bottle of 80 mL containing 40 billion LcS) daily over a long period of time from the beginning of October 2006. The health condition of the two groups was checked based on daily health records, and if diarrhea was observed, a fecal sample was collected and examined with a norovirus detection kit. Many of the subjects developed norovirus gastroenteritis in December 2006. Although the incidence of infection did not differ significantly between the two groups, the period with fever of 37 C or higher was shorter in the intake group than in the non-intake group.

Ten individuals living at the same facility (average age 83) were given one of the same LcS fermented milk servings daily for two months, and fecal flora was then compared to pre-intake levels. Results demonstrated that beneficial bifidobacteria and lactobacillus increased with intake of LcS fermented milk. On the other hand, harmful coliform bacteria decreased and the detection rate of Pseudomoanas, which can cause opportunistic and/or nosocomial infections, also decreased. In addition, the intake of LcS fermented milk increased the overall concentration of fecal short-chain fatty acids (SCFAs).

3. Discussion and Future Expectations

This study suggests that intake of LcS fermented milk is effective in decreasing fever brought on by norovirus infection. The intake of LcS fermented milk also increased bifidobacteria and lactobacillus, reduced coliform bacteria and Pseudomonas, and increased SCFA concentration (primarily acetic acid). Intestinal SCFAs suppress the growth of pathogenic organisms such as the coliform group, improve absorption capacity of water and electrolytes and peristalsis of the bowel, and also serve as an energy source for the enterocytes. Continuous intake of LcS fermented milk has also been reported to aid the recovery of reduced natural killer cell activity. It thus appears that the key factor in alleviating fever resulting from the intake of LcS fermented milk is enhanced defense function of the host due to factors such as improved intestinal flora and immunomodulatory function.

The results of this study suggest that LcS can be expected to contribute as an effective means of protection against infectious gastroenteritis including norovirus infection, and respiratory and other infections at facilities where elderly individuals with compromised immune systems live communally.

Yuichiro Yamashiro
Appointed Professor in Probiotics Research Laboratory
Juntendo University Graduate School of Medicine
Tel: +81-3-5689-0082

SOURCE Juntendo University