Results show that S boulardii
diminished the time of diarrhoea by 31.4% and shortened time with fever by 73% (table ). Children receiving the multiple species product tended to have less time with diarrhoea and no patients vomited after the treatment was started. In previous studies that administered multiple species products similar to the one we used, other authors found a rather more pronounced effect, 30 hours [14
] and 30-36 hours reduction in diarrhoeal duration [20
], in comparison with the 26 hours reduction we found. Infants hospitalized in our study were admitted with severe diarrhoea and had intense clinical manifestations in comparison to outpatients with rotavirus diarrhoea; this could explain the less intense results obtained. Although not significant, we consider relevant the trend to diminish time of diarrhoea in the group receiving the multiple probiotic products, because decreasing severity of diarrhoea may help reducing the nutritional impact of the diarrhoeal episode.
Other factors such as poor nutritional status, severe diarrhoea, severe dehydration, should not be confounding variables in this protocol because they were all exclusion criteria. Reports in the literature about children with rotavirus diarrhoea refer mainly to cases managed as outpatients. This study provides evidence that probiotics are also helpful in cases with less than 10% dehydration that require hospitalization. It is worth noting that in this study, despite one day less of diarrhoea, the total length of hospital admissions did not decrease. This was mainly due to requests of mothers and fathers to maintain the child one more day under observation in hospital because, living far from hospital; they feared their child would need to be readmitted to hospital.
Effects of probiotics on vomiting are not clear. Some studies have reported no effects [24
] whereas other authors report a significant decrease on time of vomiting [25
] or a transitory effect, observed only during some days of the episode [26
]. Our results support the effect of probiotics on vomiting, showing decreased time of vomiting in the intervention groups as compared with controls (zero versus 40 hours). However only in the multiple species product-treated group the shorter time of vomiting reached significance. Furthermore, children receiving the single species product had almost 50 hours less fever than the control group. This last feature is in contrast to studies by other authors and also the results of a study conducted in our hospital comparing Nitazoxanide to probiotics, none of which detected less time with fever [27
This study compared two probiotic products, both readily available in Bolivia, one with a single species of probiotic bacteria and the other with multiple species of probiotic bacteria. The former contains higher total concentrations of bacteria despite having only one species and yielded better results. This raises the question as to whether larger doses of one probiotic bacterial strain are more efficient than multiple species in smaller numbers.
The effect of different probiotic species and strains on diarrhoea is currently well accepted [28
]; however, the dose required to obtain the best results is less clear. In a recent study by Fang et al [33
reduced faecal excretion of rotavirus in a dose dependent fashion; authors concluded that the minimal dose required to have a positive effect was at least 6 × 108
CFU, which coincides with other authors [34
]. In a recent metanalysis by Guandalini [31
] the recommended dose was at least 5 × 109
CFU. Other authors found no effect in duration of diarrhoea using 1 × 107 L. rhamnosus
]. When we analyzed the products used in our study, we found that the mixture of probiotics included a total amount of bacteria of 1.25 × 109
; estimating the individual dosing of each probiotics present, they were well below the amount described as effective. The fact that we found positive effects on time of diarrhoea, of vomiting and of fever suggests that the total amount of bacteria present in the product indeed influences the results, but it also suggests that adequate numbers, as it was the case of the single probiotic, yields better results than a mixture in lesser numbers. Discussing the dose provided by each commercial product is relevant because there is evidence suggesting that the effect obtained is dose dependent [32
], the higher the dose the clearer effect. However, studies of adverse reactions also seem related to probiotic dosing, therefore, the appropriate amounts of bacteria should be established for each probiotic when administered in mixtures, such as that they are best inducing the effect and at the same time are safe for the patient.