• The incidence of diarrhea
  

• Incidence of rotavirus diarrhea
  

Despite the adoption of norms regarding enteric isolation, nosocomial infectious diarrhea is common in children(1;2). Viral pathogens, especially rotavirus are responsible for most of the cases. Depending on population, type of hospital, and standard of care, the reported incidence rate ranges from 8 to 33 episodes per 100 admissions(1). Infants and toddlers are at the highest risk of acquiring nosocomial viral gastroenteritis(1;2).

Probiotic bacteria have been shown to be beneficial in the prevention and treatment of gastrointestinal infections as well as reduction of viral shedding(3;4). A recent study by Szajewska et al. (2) showed a significant reduction of nosocomial infections from 33% to 7% by prophylactic treatment with LGG during the hospital stay. Another study however, did not show any difference(1).

Another approach is to use prebiotic treatment. Prebiotics are defined as non-digestible substances that, when ingested, selectively promote the growth and establishment of beneficial probiotic-like bacteria normally present in the gut(5).

Lactulose is a semi-synthetic disaccharide made from lactose by a chemical reaction which was first described in 1930(6). In contrast to other prebiotics, lactulose has up to now been mainly used as a medicinal drug for constipation and hepatic encephalopathy(6). In 1957 Petuely published the basic work about lactulose as "the bifidus factor" which was confirmed by MacGillivray et al(6).They found that the composition of the colonic microflora of bottle-fed babies is very much like that of adults while if lactulose is added to the formula milk such babies have the same composition as breast-fed babies.

Lactulose has been used for 40 years in the treatment of constipation [10] and for more than 30 years for encephalopathy.The dosages used in PSE are up to four times higher than those usually applied in constipation. No putative or definite evidence of mutagenic, genotoxic or teratogenic effects of lactulose has been obtained in human use. Animal studies in rats and rabbits also did not reveal any teratogenic or reproduction-toxicologic effects, and even high dosages have had no deleterious effects(6)

Our hypothesis is that lactulose, with its proven prebiotic properties, given to children during their hospital stay, would be beneficial in reducing nosocomial infections.