***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objectives . Antimicrobial treatment may disturb the colonization resistance of gastrointestinal microflora , which may induce clinical symptoms , most commonly diarrhea . The severity of antibiotic-associated diarrhea may range from a brief , self-limiting disease to devastating diarrhea with electrolyte disturbances , dehydration , crampy abdominal pain , pseudomembranous colitis , toxic megacolon , or even death . The incidence of diarrhea in children receiving a single antimicrobial treatment is unclear . In addition to more critical use of antimicrobials , adjunctive preventive measures to antibiotic-associated diarrhea are needed . The objective of this study was to evaluate the incidence of diarrhea after antimicrobial treatment in children with no history of antimicrobial use during the previous 3 months . Another aim of this study was to assess the preventive potential of Lactobacillus rhamnosus GG ( Lactobacillus GG ; American Type Culture Collection 53103 ) , a probiotic strain with a documented safety record and a therapeutic effect in viral gastroenteritis on antibiotic-associated diarrhea . Methods . Oral antimicrobial agents were prescribed for the treatment of acute respiratory infections at the clinics of the Health Care Center of the City of Tampere or Tampere University Hospital , Finl and , to 167 patients who were invited to participate in the study . Of the patients , 48 were lost to follow-up ; therefore , the final study population consisted of 119 children from 2 weeks to 12.8 years of age ( mean : 4.5 years ) . All study subjects met the inclusion criteria : they had not received any antimicrobial medication during the previous 3 months , they did not suffer from gastrointestinal disorders , and they did not need intravenous antimicrobial treatment . The patients were r and omized to receive placebo or 2 × 1010 colony-forming units of Lactobacillus GG in capsules given twice daily during the antimicrobial treatment . Lactobacillus GG and placebo capsules were indistinguishable in appearance and taste . The parents kept a daily symptom diary and recorded stool frequency and consistency at home for 3 months . Diarrhea was defined as at least three watery or loose stools per day for a minimum of 2 consecutive days . In the case of diarrhea , viral ( adenovirus , rotavirus , calicivirus and astrovirus ) and bacterial ( Salmonella , Shigella , Yersinia , Campylobacter , Clostridium difficile , Staphylococcus aureus , and yeasts ) analyses were studied in fecal sample s. The metabolic activity of the gut microflora was assessed by analysis of fecal urease , β-glucosidase , and β-glucuronidase activities . The primary outcome measure was diarrhea during the first 2 weeks after the beginning of the antimicrobial treatment , because this period most likely reflects the effects of antimicrobial use . Secondary outcome measures were the activities of fecal urease , β-glucuronidase , and β-glucosidase . Results . On the entire follow-up , 80 % of any gastrointestinal symptoms were reported during the first 2 weeks after the beginning of the antimicrobial treatment . The incidence of diarrhea was 5 % in the  Lactobacillus GG group and 16 % in the placebo group within 2 weeks of antimicrobial therapy ( χ2 = 3.82 ) . The treatment effect ( 95 % confidence interval ) of Lactobacillus GG was −11 % ( −21%–0 % ) . In diarrheal episodes , the viral and bacterial analyses were positive for Clostridium difficile in 2 cases and for Norwalk-like calicivirus in 3 cases . The age of the patients with diarrhea was between 3 months and 5 years in 75 % of cases in both groups .  The severity of diarrhea was comparable in the study groups , as evidence d by similar stool frequency ( mean : 5 per day ; range : 3–6 ) and the duration of diarrhea ( mean : 4 days ; range : 2–8 ) . The activities of fecal urease and β-glucuronidase , but not β-glucosidase , changed significantly after the beginning of the antimicrobial treatment in the Lactobacillus GG group and in the placebo group alike . The decrease in urease and β-glucuronidase activities was reversible in patients with no diarrhea , but in patients with diarrhea , the modifications in gut microflora were more profound and prolonged . The activities of the three enzymes were normalized within 3 weeks , evidence d by stable enzyme activities in sample s collected 3 weeks , 1 month , and 3 months after the beginning of the antimicrobial treatment , compared with those obtained before treatment . Discussion . In the present study , after a single antimicrobial treatment , the incidence of diarrhea was 16 % . The higher incidence of antibiotic-associated diarrhea in previous reports may be attributable to a recent antimicrobial therapy that disturbs intestinal flora and exposes to complications . Also , in the present study , changes in the metabolic activity of the intestinal flora were observed , evidence d by a transient decline in fecal enzyme activities . Different probiotic preparations , including lactobacilli , are recommended frequently to prevent antibiotic-associated diarrhea . Although probiotics have been shown to be efficient in the prevention and the treatment of viral gastroenteritis , their usefulness during antimicrobial therapy in children has not been eluci date d before . We observed that the administration of Lactobacillus GG to children receiving antimicrobial therapy for respiratory infection reduced the incidence of antibiotic-associated diarrhea to one third . The beneficial effect may be mediated by a number of functions of probiotics , ie , production of antimicrobial substances , local competition of adhesion receptors and nutrients , and stimulation of intestinal antigen specific and nonspecific immune responses . Conclusion . A probiotic strain , Lactobacillus GG , is effective in the prevention of diarrhea in children receiving antimicrobial treatment to respiratory infections Lactobacillus paracasei has been demonstrated to inhibit the growth of many pathogenic microbes such as Streptococcus mutans , in vitro . However , its clinical application remains unclear . Here , we examined whether a novel probiotic L. paracasei GMNL-33 may reduce the caries-associated salivary microbial counts in healthy adults . Seventy-eight subjects ( aged 20 to 26 ) had completed this double-blinded , r and omized , placebo-controlled study . A probiotic/test ( n = 42 ) and a control group ( n = 36 ) took a L. paracasei GMNL-33 and a placebo oral tablet three times per day for 2 weeks , respectively . Bacterial counts of salivary S. mutans , lactobacilli , and salivary buffer capacity were measured with chair-side kits at the beginning ( T1 ) , the completion ( T2 ) of medication , and 2 weeks after medication ( T3 ) . The results did not show differences in the counts of S. mutans and lactobacilli between probiotic and control groups at T1 , T2 , and T3 . Nevertheless , within the probiotic group , an interesting probiotic effect was noticed . Between T1 and T2 , no inhibitory effect against S. mutans was observed . However , a significant count reduction in the salivary S. mutans was detected between T2 and T3 ( p = 0.016 ) . Thus , a 2-week period of medication via oral administration route may be needed for L. paracasei GMNL-33 to be effective in the probiotic action Objectives The hypothesis was that the daily use of a high dose of a xylitol chewing gum for 6 months would reduce the increment of decayed permanent first molar surfaces ( ΔD6S ) in high-risk schoolchildren after 2 years . Methods In this r and omised , clinical trial , 204 schoolchildren with a high caries risk were assigned to two experimental groups , xylitol and non-xylitol . Caries status , salivary mutans streptococci , and lactobacilli were re-evaluated 2 years later in 74 xylitol-treated and 83 non-xylitol-treated schoolchildren . Differences in mean ∆D6S between groups registered at baseline and at follow-up were evaluated using the nonparametric Mann – Whitney U test . Results Outcome was the development of detectable carious lesions initial ( D1–D2 ) and manifest ( D3 ) in the permanent first molars . In the xylitol group , the difference in proportion of children with decayed first permanent molars at baseline and follow-up was 1.43 % for manifest lesion and 2.86 % for initial lesions ; while in the non-xylitol group was 10.26 % ( p < 0.01 ) and 16.66 % ( p < 0.01 ) , respectively . A statistically significant difference regarding means was also observed in the non-xylitol group : the ∆D6S for manifest lesion was 0.18 ( p = 0.03 ) and 0.67 ( p = 0.02 ) for initial lesion . Conclusion The use of a chewing gum containing a high dose of xylitol for a period of 6 months has been shown to produce a long-term effect on caries development in high caries-risk children . Clinical relevance A school-based preventive programme based on 6 months ’ administration of a high dose of xylitol via chewing gum proved to be efficacious in controlling caries increment in high-risk children Preterm infants are prone to abnormal bacterial colonization of the intestine with ensuing adverse health effects . To examine whether the oral application of Bifidobacterium lactis Bb12 ( probiotic ) may improve selected indicators of health status in preterm infants , a double blind , placebo controlled r and omized clinical study was performed on 69 preterm infants ( < 37 gestation wk ) .  Weight gain was defined as the primary outcome measure . In antibiotic-treated infants , probiotic supplementation result ed in a higher body weight compared with placebo ( p < 0.001 ) . In the probiotic group , the fecal pH was significantly lower than in the placebo group . The fecal concentrations of acetate and lactate were 42 and 38 % higher , respectively , in the probiotic group than in the placebo group . Fecal calprotectin was lower in the probiotic group ( p = 0.041 ) , while fecal IgA was higher in this group compared with the placebo group ( p = 0.021 ) Background The increasing interest in probiotic lactobacilli in health maintenance has raised the question of potential risks . One possible side effect could be an increased acidogenicity in dental plaque . The aim of this study was to investigate the effect of probiotic lactobacilli on plaque lactic acid ( LA ) production in vitro and in vivo . Methods In the first part ( A ) , suspensions of two lactobacilli strains ( L. reuteri DSM 17938 , L. plantarum 299v ) were added to suspensions of supragingival dental plaque collected from healthy young adults ( n=25 ) . LA production after fermentation with either xylitol or fructose was analyzed . In the second part ( B ) , subjects ( n=18 ) were given lozenges with probiotic lactobacilli ( L. reuteri DSM 17938 and ATCC PTA 5289 ) or placebo for two weeks in a double-blinded , r and omized cross-over trial . The concentration of LA in supragingival plaque sample s was determined at baseline and after 2 weeks . Salivary counts of mutans streptococci ( MS ) and lactobacilli were estimated with chair-side methods . Results Plaque suspensions with L. reuteri DSM 17938 produced significantly less LA compared with L. plantarum 299v or controls ( p<0.05 ) . Fructose gave higher LA concentrations than xylitol . In part B , there were no significant differences in LA production between baseline and follow up in any of the groups and no differences between test and placebo were displayed . The salivary MS counts were not significantly altered during the intervention but the lactobacilli counts increased significantly in the test group ( p<0.05 ) . Conclusion Lactic acid production in suspensions of plaque and probiotic lactobacilli was strain-dependant and the present study provides no evidence of an increase in plaque acidity by the supply of selected probiotic lactobacilli when challenged by fructose or xylitol . The study protocol was approved by The Danish National Committee on Biomedical Research Ethics ( protocol no H-2 - 2010 - 112).Trial registration BACKGROUND Previous studies have suggested that lactobacilli-derived probiotics in dairy products may affect oral ecology , but the effects of different delivery methods have received little attention . AIM The aim of the present study was to investigate the effect of the probiotic Lactobacillus reuteri , delivered by a new medical device , on the levels of salivary mutans streptococci and lactobacilli in young women with high Streptococcus mutans counts . DESIGN This is a r and omized , double-blind , placebo-controlled study involving 20 healthy young women ( aged 20 years ) : 10 as subjects and 10 as 
    Output:
    
Probiotics may play a role as antagonistic agent on mutans streptococci ( MS ) , acidogenic/aciduric bacteria that contributes to the caries process .
In two-thirds of the selected papers , probiotics have demonstrated the capacity to reduce MS counts in saliva and /or plaque in short-term .