Probiotics in antibiotic-associated diarrhoea

In Vivo Efficacy of Bacillus velezensis Isolated from Korean Gochang Bokbunja Vinegar against Carbapenem-Resistant Klebsiella pneumoniae Infections

Outbreaks of carbapenem-resistant Enterobacteriaceae (CRE), especially Klebsiella pneumoniae (CRKP), are commonly reported as severe infections in hospitals and long-term care settings, and their occurrence is increasing globally. Conventional antibiotics used for treating CRE have become ineffective due to resistance development. Furthermore, their safety issues restrict their availability and use for CRE treatment. Therefore, developing new drugs different from existing drugs to combat this deadly menace is urgently needed. Probiotics can be a potential option in this context, as probiotics' efficacy against a variety of infectious illnesses has already been well established. Here, we report the effect of the Bacillus velezensis strain isolated from Gochang Bokbunja vinegar in Korea on CRE infection using two mouse models. Data showed that pretreatment with B. velezensis significantly reduced body weight loss and mortality of CRKP-infected mice in the preventive model. The oral administration of B. velezensis in a therapeutic model also decreased the mortality and illness severity in CRKP-infected mice. Moreover, a two-week oral acute toxicity assay in guinea pigs did not reveal any aberrant clinical signs. Our findings demonstrate the potential effectiveness of our candidate probiotic strain, B. velezensis, against CRKP, suggesting that it could be used as an antimicrobial agent for treating CRKP-related infections.

Meta-analysis of the effects of Bifidobacterium preparations for the prevention and treatment of pediatric antibiotic-associated diarrhea in China

Bifidobacterium preparations are increasingly used for pediatric antibiotic-associated diarrhea (AAD) in China. The aim of this study was to review existing evidence on the efficacy of Bifidobacterium preparations for the prevention and treatment of pediatric AAD in China. Searches were performed with Medline, Embase, Cochrane Central Register of Controlled Trials, CNKI, and CBM databases. Thirty trials met the inclusion criteria. Of the 30 trials, five Bifidobacterium preparations were included. The preparations were all Bifidobacterium based, in combined with Lactobacillus, Enterococcus, Bacillus, Streptococcus or Clostridium strains. The pooled results of the 30 trials, which included 7225 participants, indicated a statistically significant association of Bifidobacterium preparations administration with reduction in pediatric AAD (odds ratio [OR], 0.33; 95% confidence interval [CI], 0.29-0.39; P<0.01). When the meta-analysis was re-performed according to the trials explicitly aiming to prevent or treat pediatric AAD, respectively, the pooled results were similar (Bifidobacterium preparations use for preventing pediatric AAD (n=21): pooled OR, 0.34, 95% CI, 0.28-0.41, P<0.01; Bifidobacterium preparations use for treating pediatric AAD (n=9): pooled OR, 0.32, 95% CI, 0.23-0.43, P<0.01). Subgroup analyses which based on Bifidobacterium preparations variety, clinical condition, or participant's age also showed statistically significant benefit of adjunct Bifidobacterium preparations for the prevention and treatment of pediatric AAD in China. The pooled evidence suggested that Bifidobacterium preparations might be efficacious for the prevention and treatment of pediatric AAD in China.

Probiotics and small bowel mucosa: Molecular aspects of their interactions

Probiotics are described as "friendly bacteria" that could improve the intestine defense by interacting with the resident microflora. There is a large body of evidence suggesting that consumption of functional food containing probiotics exerts positive effects on human health. Several clinical trials have highlighted the efficiency of probiotics in the prevention and treatment of different gastrointestinal disorders including the prevention of antibiotic associated diarrhea, the remission in patients with inflammatory bowel disease, beneficial effects against Helicobacter pylori infection, positive effects in patients affected by allergies and atopic diseases. The clinical benefits of probiotics use are mainly attributed to their antimicrobial substances production and their positive interactions with the enterocytes to reinforce the intestinal epithelial barrier. Moreover, there is evidence suggesting that probiotics stimulate both specific and non-specific host immune responses. Recently, have been published some experiments performed with the DNA microarray technology which provided a global gene screening of the complex bacteria-host interplay. Nevertheless, the molecular mechanisms by which probiotics enhance the intestinal host defense are still not completely elucidated. Here, we review the experiments and clinical studies to date on the complex mechanisms regulating the communication between probiotics and their hosts.

Probiotic fortified diet reduces bacterial colonization and translocation in a long-term neonatal rabbit model

BACKGROUND

Probiotic fortified diet reduces bacterial colonization and translocation in a short-term neonatal rabbit model when continuously challenged with pathogen. The purpose of this study was to determine if live probiotic diet could remain effective at decreasing colonization/translocation of pathogens in a long-term neonatal rabbit model without ill effects of the probiotic outside the gastrointestinal (GI) tract.

METHODS

Rabbit pups were born via cesarean delivery 1 day preterm and assigned to 2 diets: a newly formulated diet (controls) vs the same diet fortified with the live probiotic Lactoccocus lactis. Enterobacter cloacae was added to both preparations before each feed. Pups were gavage fed twice daily, and weights were recorded. Rabbits were sacrificed on day 7, and organs were harvested and cultured for target organism growth.

RESULTS

The probiotic fortified diet resulted in a significant decrease in Enterobacter translocation to the liver and decreased colonization in the stomach and lungs. There was no evidence of Lactococccus translocation or colonization outside of the GI tract.

CONCLUSION

This probiotic fortified diet was effective at decreasing pathogenic bacteria colonization and translocation in a long-term neonatal model. The addition of L lactis to the diet resulted in appropriate growth without any colonization or translocation of the probiotic outside of the GI tract.

Formula fortified with live probiotic culture reduces pulmonary and gastrointestinal bacterial colonization and translocation in a newborn animal model

BACKGROUND/PURPOSE

Acidified diets are protective against intestinal bacterial colonization and translocation. Probiotic diets are designed to modulate the intestinal flora to enhance mucosal immunity. This study was designed to determine if formula acidified with live probiotic decreases bacterial gut colonization and translocation, and is equally tolerated as other acidified diets.

METHODS

One hundred twenty-eight rabbit pups delivered via cesarean section [cesarean delivery, cesarean birth, abdominal delivery] were randomly assigned to 4 feeding groups: NAN Nestle (control, pH 7.0), NAN acidified with citric acid (pH 4.55), biologically acidified Pelargon (pH 4.55), and NAN with live Lactococcus lactis culture (pH 4.2). Pups were gavage fed every 12 hours with Enterobacter cloacae challenges of 10 colony-forming units/mL per feed and killed on day of life 3. Lungs, liver, spleen, mesenteric lymph nodes (MLNs), stomach, and cecum were cultured and quantitatively analyzed for target organism growth. Results were analyzed using chi(2) tests.

RESULTS

NAN with live probiotic culture, when compared with Pelargon, acidified NAN, and NAN, significantly reduced the incidence of Enterobacter pulmonary colonization (P < .01), bacterial translocation (liver, P < .025; spleen and MLN, P < .05), and gastric and intestinal colonization (P < .001 for both).

CONCLUSION

Probiotic-fortified formula provides superior protection against pulmonary and gastrointestinal bacterial colonization and translocation compared with neutral and acidified formulas, and is equally tolerated.

Antibiotic-associated diarrhoea

Diarrhoea is a common complication of antimicrobial therapy. The term antibiotic-associated diarrhoea (AAD) is often considered synonymous with Clostridium difficile. In fact, AAD can develop through a variety of mechanisms and manifest through a broad range of clinical signs and symptoms. For improved prevention and recognition of AAD, it is important to understand the pathophysiology and risk factors for AAD. Although Clostridium difficile continues to be the most common identifiable pathogen of AAD, many patients with AAD can be managed through a variety of conservative measures. This review focuses on some of the important distinctions between nonspecific AAD and antibiotic-associated colitis. In addition, the most recent data on important risk factors for the development of AAD are summarised. Given its pathogenicity, there will be an emphasis on the early diagnosis, treatment and prevention of Clostridium difficile-associated diarrhoea. AAD is a common clinical problem that can progress to severe, life-threatening disease if not recognised quickly. Better awareness of risk factors can lead to the most efficacious treatment of this disorder: primary prevention.

Prevention of antibiotic-associated diarrhoea by a fermented probiotic milk drink

OBJECTIVE

To study the preventive effect of a milk drink fermented with multistrain probiotics on antibiotic associated diarrhoea (AAD).

DESIGN

Double-blind placebo controlled study.

SETTING

University Hospital of North Norway.

SUBJECTS AND METHODS

Of 853 patients treated with antibiotics, 87 met the inclusion criteria, and were randomized to ingestion of a fermented milk drink containing LGG, La-5 and Bb-12 (n=46) or placebo with heat-killed bacteria (n=41), during a period of 14 days. A diary was recorded, and stool samples were collected for microbiological analyses.

RESULTS

Sixty-three patients completed the study according to the protocol; two patients (5.9%) in the treatment group and eight (27.6%) in the placebo group developed AAD (P=0.035). The relative risk of developing AAD was 0.21 (95% confidence interval: 0.05-0.93) when given probiotic milk drink.

CONCLUSION

A fermented multistrain probiotic milk drink may prevent four of five cases of AAD in adult hospitalized patients.

SPONSORSHIP

TINE BA, Oslo, Norway.

Inhibition of Clostridium difficile growth and adhesion to enterocytes by Bifidobacterium supernatants

The antimicrobial and anti-adhesive effects of extracellular factors from 27 strains of bifidobacteria isolated from healthy infants were tested against two reference strains of Clostridium difficile (ATCC 9689 and ATCC 43593). All bifidobacterial supernatants at pHs between 5.0 and 4.1 were able to produce strain-dependent growth inhibition of clostridia in the agar-diffusion assay. Six strains of Bifidobacterium produced during growth extracellular factors able to antagonize the adhesion of C. difficile ATCC 9689 and ATCC 43593 to cultured human enterocytes (Caco-2/TC7). Factors responsible for the anti-adhesive effect were thermolabile, active at neutral pH and unaffected by proteolytic cleavage (proteinase K and chymotrypsin). Results of the present paper show the potential of selected bifidobacteria to antagonize key mechanisms involved in the virulence of C. difficile.

Effect of regular ingestion of Saccharomyces boulardii plus inulin or Lactobacillus acidophilus LB in children colonized by Helicobacter pylori

AIM

To evaluate the effect of a probiotic, Lactobacillus acidophilus LB (LB), or a synbiotic, Saccharomyces boulardii plus inulin (SbI), on Helicobacter pylori (Hp) colonization in children.

SUBJECTS AND METHODS

A clinical trial was carried out in a school from a low socio-economic area of Santiago. Two hundred and fifty-four asymptomatic children (8.40+/-1.62 y) were screened for Hp by the (13)C-Urea Breath Test ((13)C-UBT). Hp-positive children were randomly distributed into three groups to receive either antibiotic treatment (lanzoprazole, clarythromycin and amoxicillin) for 8 d, or SbI or LB daily for 8 wk. A second (13)C-UBT was carried out at this time. Spontaneous clearance was evaluated in the same way in 81 infected, untreated children. The differences in the delta(13)CO(2) over baseline values before and after treatments (?DOB) were evaluated.

RESULTS

182 subjects (71.7%) were colonized by Hp, and 141 of them completed their treatment (22.5% dropout). Hp was eradicated in 66%, 12% and 6.5% of the children from the Ab, SbI and LB groups, respectively, while no spontaneous clearance was observed in the children without treatment. A moderate but significant difference in ?DOB was detected in children receiving living SbI (-6.31; 95% CI: -11.84 to -0.79), but not in those receiving LB (+0.70; 95% CI: -5.84 to +7.24).

CONCLUSION

S. boulardii seems promising as an agent that interferes with Hp in colonized individuals. More studies are needed to confirm these results and to elucidate the mechanisms by which Sb inhibits Hp.

Review article: bifidobacteria as probiotic agents -- physiological effects and clinical benefits

Bifidobacteria, naturally present in the dominant colonic microbiota, represent up to 25% of the cultivable faecal bacteria in adults and 80% in infants. As probiotic agents, bifidobacteria have been studied for their efficacy in the prevention and treatment of a broad spectrum of animal and/or human gastrointestinal disorders, such as colonic transit disorders, intestinal infections, and colonic adenomas and cancer. The aim of this review is to focus on the gastrointestinal effects of bifidobacteria as probiotic agents in animal models and man. The traditional use of bifidobacteria in fermented dairy products and the GRAS ('Generally Recognised As Safe') status of certain strains attest to their safety. Some strains, especially Bifidobacterium animalis strain DN-173 010 which has long been used in fermented dairy products, show high gastrointestinal survival capacity and exhibit probiotic properties in the colon. Bifidobacteria are able to prevent or alleviate infectious diarrhoea through their effects on the immune system and resistance to colonization by pathogens. There is some experimental evidence that certain bifidobacteria may actually protect the host from carcinogenic activity of intestinal flora. Bifidobacteria may exert protective intestinal actions through various mechanisms, and represent promising advances in the fields of prophylaxis and therapy.

Lactobacillus and bifidobacterium in irritable bowel syndrome: symptom responses and relationship to cytokine profiles

BACKGROUND & AIMS

The aim of this study was to compare the response of symptoms and cytokine ratios in irritable bowel syndrome (IBS) with ingestion of probiotic preparations containing a lactobacillus or bifidobacterium strain.

METHODS

Seventy-seven subjects with IBS were randomized to receive either Lactobacillus salivarius UCC4331 or Bifidobacterium infantis 35624, each in a dose of 1 x 10 10 live bacterial cells in a malted milk drink, or the malted milk drink alone as placebo for 8 weeks. The cardinal symptoms of IBS were recorded on a daily basis and assessed each week. Quality of life assessment, stool microbiologic studies, and blood sampling for estimation of peripheral blood mononuclear cell release of the cytokines interleukin (IL)-10 and IL-12 were performed at the beginning and at the end of the treatment phase.

RESULTS

For all symptoms, with the exception of bowel movement frequency and consistency, those randomized to B infantis 35624 experienced a greater reduction in symptom scores; composite and individual scores for abdominal pain/discomfort, bloating/distention, and bowel movement difficulty were significantly lower than for placebo for those randomized to B infantis 35624 for most weeks of the treatment phase. At baseline, patients with IBS demonstrated an abnormal IL-10/IL-12 ratio, indicative of a proinflammatory, Th-1 state. This ratio was normalized by B infantis 35624 feeding alone.

CONCLUSIONS

B infantis 35624 alleviates symptoms in IBS; this symptomatic response was associated with normalization of the ratio of an anti-inflammatory to a proinflammatory cytokine, suggesting an immune-modulating role for this organism, in this disorder.

Antagonistic activities of lactobacilli and bifidobacteria against microbial pathogens

The gastrointestinal tract is a complex ecosystem that associates a resident microbiota and cells of various phenotypes lining the epithelial wall expressing complex metabolic activities. The resident microbiota in the digestive tract is a heterogeneous microbial ecosystem containing up to 1 x 10(14) colony-forming units (CFUs) of bacteria. The intestinal microbiota plays an important role in normal gut function and maintaining host health. The host is protected from attack by potentially harmful microbial microorganisms by the physical and chemical barriers created by the gastrointestinal epithelium. The cells lining the gastrointestinal epithelium and the resident microbiota are two partners that properly and/or synergistically function to promote an efficient host system of defence. The gastrointestinal cells that make up the epithelium, provide a physical barrier that protects the host against the unwanted intrusion of microorganisms into the gastrointestinal microbiota, and against the penetration of harmful microorganisms which usurp the cellular molecules and signalling pathways of the host to become pathogenic. One of the basic physiological functions of the resident microbiota is that it functions as a microbial barrier against microbial pathogens. The mechanisms by which the species of the microbiota exert this barrier effect remain largely to be determined. There is increasing evidence that lactobacilli and bifidobacteria, which inhabit the gastrointestinal microbiota, develop antimicrobial activities that participate in the host's gastrointestinal system of defence. The objective of this review is to analyze the in vitro and in vivo experimental and clinical studies in which the antimicrobial activities of selected lactobacilli and bifidobacteria strains have been documented.