Importance of Molecular Methods to Determine Whether a Probiotic is the Source of Lactobacillus Bacteremia

Lactobacillus Bacteremia and Probiotics: A Review

Lactobacilli are widely found in nature, are commensal microbes in humans, and are commonly used as probiotics. Concerns about probiotic safety have arisen due to reports of bacteremia and other Lactobacillus-associated infections. We reviewed the literature for articles on the pathogenicity of Lactobacillus spp. bacteremia and reports of probiotics in these patients. Our aim is to review these articles and update the present knowledge on the epidemiology of Lactobacillus spp. bacteremia and determine the role of probiotics in Lactobacillus bacteremia. Lactobacillus bacteremia is infrequent but has a higher risk of mortality and risk factors, including severe underlying diseases, immune system suppression, admission to intensive care units, and use of central venous catheters. A variety of Lactobacillus species may cause bacteremia and may or may not be associated with probiotic exposure. To determine if oral probiotics are the source of these infections, the blood isolates and the oral probiotic strain(s) must be compared by sensitive identification methods. The prevalence of Lactobacillus bacteremia is infrequent but is more common in patients taking probiotics compared to those not taking probiotics. Three probiotics (Lacticaseibacillus rhamnosus GG, Lactiplantibacillus plantarum, and Lacticaseibacillus paracasei) were directly linked with blood isolates from bacteremia patients using molecular identification assays.

In vitro investigation on lactic acid bacteria isolatedfrom Yak faeces for potential probiotics

In order to evaluate the potential and safety of lactic acid bacteria (LAB) isolated from faeces samples of Ganan yak as probiotic for prevention and/or treatment of yak diarrhea, four strains of LAB including Latilactobacillus curvatus (FY1), Weissella cibaria (FY2), Limosilactobacillus mucosae (FY3), and Lactiplantibacillus pentosus (FY4) were isolated and identified in this study. Cell surface characteristics (hydrophobicity and cell aggregation), acid resistance and bile tolerance, compatibility, antibacterial activity and in vitro cell adhesion tests were also carried out to evaluate the probiotic potential of LAB. The results showed that the four isolates had certain acid tolerance, bile salt tolerance, hydrophobicity and cell aggregation, all of which contribute to the survival and colonization of LAB in the gastrointestinal tract. There is no compatibility between the four strains, so they can be combined into a mixed probiotic formula. Antimicrobial tests showed that the four strains were antagonistic to Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium. Moreover, the in vitro safety of the four isolates were determined through hemolytic analysis, gelatinase activity, and antibacterial susceptibility experiments. The results suggest that all the four strains were considered as safe because they had no hemolytic activity, no gelatinase activity and were sensitive to most antibacterial agents. Moreover, the acute oral toxicity test of LAB had no adverse effect on body weight gain, food utilization and organ indices in Kunming mice. In conclusion, the four LAB isolated from yak feces have considerable potential to prevent and/or treat yak bacterial disease-related diarrhea.

Bacteraemia Caused by Probiotic Strains of Lacticaseibacillus rhamnosus—Case Studies Highlighting the Need for Careful Thought before Using Microbes for Health Benefits

Lactic acid bacteria belonging to Lactobacillus spp. and Lacticaseibacillus spp. are a natural part of fermented milk and other food products, probiotic supplements and human microbiota. They mainly belong to mucosal microflora, especially oral, vaginal and intestinal. Lacticaseibacillus spp. strains included in probiotics are generally characterised as safe microorganisms, and the species are concerned bacteria with very low pathogenic potential. However, infections caused by Lactobacillus spp. and Lacticaseibacillus spp., including bacteraemia and endocarditis, occur occasionally. The aim of the study was to present two cases of bacteraemia due to Lacticaseibacillus rhamnosus associated with the use of a probiotic product. It afflicted patients in intensive care units. The investigation was preliminarily based on clinical and microbiological recognition of the cases. The initial observation was laboratory confirmed with the application of pulsed-field gel electrophoresis (PFGE) results. Identical PFGE patterns were obtained for the evaluated strains and the strains derived from a commercially available probiotic that was administered to those patients. The increasing number of studies describing opportunistic infections due to probiotic strains of Lacticaseibacillus spp. should result in verifying the safety of probiotic formulations used in immunocompromised patients and forming detailed guidelines for the use of probiotics among patients from several risk groups.

Screening and Characterization of Some Lactobacillaceae for Detection of Cholesterol-Lowering Activities

Dyslipidemia, specifically abnormal levels of low-density lipoprotein cholesterol (LDL-C), is an important risk factor of cardiovascular disease. Evidence showing the promising abilities of probiotics to lower total cholesterol or LDL-C has, however, not yet convinced experts to recommend probiotic bacteria as treatment for blood lipid management. Therefore, there are opportunities for the development of new efficient cholesterol-lowering probiotics. Bile salt hydrolase (BSH) and feruloyl esterase (FAE) are bacterial enzymes proposed to explain the cholesterol-lowering capacity of some bacteria and have both been shown to be responsible for lipid reduction in vivo. Here, in order to select for cholesterol-lowering bacteria, 70 strains related to Lactobacillaceae were screened for BSH and FAE activities. Based on this two-way screening approach, two bacteria were selected and assessed for their capacity to assimilate cholesterol in vitro, another suggested mechanism. Lactobacillus acidophilus CL1285 showed BSH and FAE activity as well as capacity to assimilate cholesterol in vitro. Lactiplantibacillus plantarum CHOL-200 exhibited BSH activity and ability to assimilate cholesterol. These properties observed in vitro make both strains good probiotic candidates for the management of dyslipidemia. Further investigation is needed to assess their ability to reduce blood cholesterol in human trial.

Fermentation products of Danshen relieved dextran sulfate sodium-induced experimental ulcerative colitis in mice

With the increased incidence and recognition, ulcerative colitis (UC) has become a global public health problem in the world. Although many immunosuppressant and biological drugs have been used for UC treatment, the cure rate is still very low. It is necessary to find some safe and long-term used medicine for UC cure. Recently, the Chinese traditional herb Danshen has been investigated in the treatment of UC. However, it is a limitation of Danshen that many of the active components in Danshen are not easily absorbed by the human body. Probiotics could convert macromolecules into smaller molecules to facilitate absorption. Thus, Lactobacillus rhamnosus (F-B4-1) and Bacillus subtillis Natto (F-A7-1) were screened to ferment Danshen in this study. The fermented Danshen products were gavaged in the dextran sulfate sodium (DSS)-induced UC model mice. Danshen had better results to attenuate symptoms of DSS-induced UC after fermented with F-B4-1 and F-A7-1. Loss of body weight and disease activity index (DAI) were reduced. The abnormally short colon lengths and colonic damage were recovered. And fermented Danshen had the better inhibitory effect than Danshen itself on pro-inflammatory cytokine expression during DSS-induced UC. The results indicated that compared with Danshen, fermented Danshen relieved DSS-induced UC in mice more effectively. Danshen fermented by probiotics might be an effective treatment to UC in clinic stage in the future.

Meningoencephalitis caused by Lactobacillus plantarum - case report

Specific strains of Lactobacillus spp. are widely used as probiotic agents but it has been repeatedly reported that may have a pathogenic potential. We present the report on a case of meningoencephalitis caused by Lactobacillus plantarum in a 63-year-old man with newly diagnosed metastatic planoepitheliale lung cancer. The patient was hospitalised due to newly diagnosed cancer and during the course of hospitalisation developed symptoms of neuroinfection. On the basis of the symptoms and results of the conducted tests the patient was diagnosed with bacterial meningoencephalitis. In microbiological tests of the blood and cerebrospinal fluid L. plantarum was cultured. During the course of antibiotic therapy the patient's condition improved. Lactobacilli are now recognised as a causative agent of infection, most notably bacteraemia. To our knowledge, this is the fourth documented case of Lactobacillus-associated neuroinfection, and only the second in an adult. Lactobacilli cause mostly opportunistic infections in immunocompromised individuals.

Effectiveness of Probiotic for Primary Prevention of Clostridium difficile Infection: A Single-Center Before-and-After Quality Improvement Intervention at a Tertiary-Care Medical Center

OBJECTIVETo evaluate probiotics for the primary prevention of Clostridium difficile infection (CDI) among hospital inpatients.DESIGNA before-and-after quality improvement intervention comparing 12-month baseline and intervention periods.SETTINGA 694-bed teaching hospital.INTERVENTIONWe administered a multispecies probiotic comprising L. acidophilus (CL1285), L. casei (LBC80R), and L. rhamnosus (CLR2) to eligible antibiotic recipients within 12 hours of initial antibiotic receipt through 5 days after final dose. We excluded (1) all patients on neonatal, pediatric and oncology wards; (2) all individuals receiving perioperative prophylactic antibiotic recipients; (3) all those restricted from oral intake; and (4) those with pancreatitis, leukopenia, or posttransplant. We defined CDI by symptoms plus C. difficile toxin detection by polymerase chain reaction. Our primary outcome was hospital-onset CDI incidence on eligible hospital units, analyzed using segmented regression.RESULTSThe study included 251 CDI episodes among 360,016 patient days during the baseline and intervention periods, and the incidence rate was 7.0 per 10,000 patient days. The incidence rate was similar during baseline and intervention periods (6.9 vs 7.0 per 10,000 patient days; P=.95). However, compared to the first 6 months of the intervention, we detected a significant decrease in CDI during the final 6 months (incidence rate ratio, 0.6; 95% confidence interval, 0.4-0.9; P=.009). Testing intensity remained stable between the baseline and intervention periods: 19% versus 20% of stools tested were C. difficile positive by PCR, respectively. From medical record reviews, only 26% of eligible patients received a probiotic per the protocol.CONCLUSIONSDespite poor adherence to the protocol, there was a reduction in the incidence of CDI during the intervention, which was delayed ~6 months after introducing probiotic for primary prevention.Infect Control Hosp Epidemiol 2018;765-770.

Primary prevention of Clostridium difficile infections with a specific probiotic combining Lactobacillus acidophilus, L. casei, and L. rhamnosus strains: assessing the evidence

Clostridium difficile infection (CDI) has become the leading healthcare-associated infection and cause of outbreaks around the world. Although various innovative treatments have been developed, preventive strategies using multi-faceted infection control programmes have not been successful in reducing CDI rates. The major risk factor for CDI is the disruption of the normally protective gastrointestinal microbiota, typically by antibiotic use. Supplementation with specific probiotics has been effective in preventing various negative outcomes, including antibiotic-associated diarrhoea and CDI. However, a consensus of which probiotic strains might prevent CDI has not been reached and meta-analyses report high degrees of heterogeneity when studies of different probiotic products are pooled together. We searched the literature for probiotics with sufficient evidence to assess clinical efficacy for the prevention of CDI and focused on one specific probiotic formulation comprised of three lactobacilli strains (Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, Lactobacillus rhamnosus CLR2, Bio-K+) for its ability to prevent CDI in healthcare settings. A literature search on this probiotic formulation was conducted using electronic databases (PubMed, Google Scholar), abstracts from infectious disease and infection control meetings, and communications from the probiotic company. Supporting evidence was found for its mechanisms of action against CDI and that it has an excellent safety and tolerability profile. Evidence from randomized controlled trials and facility-level interventions that administer Bio-K+ show reduced incidence rates of CDI. This probiotic formulation may have a role in primary prevention of healthcare-associated CDI when administered to patients who receive antibiotics.

Genotypic and phenotypic diversity of Lactobacillus rhamnosus clinical isolates, their comparison with strain GG and their recognition by complement system

Lactobacillus rhamnosus strains are ubiquitous in fermented foods, and in the human body where they are commensals naturally present in the normal microbiota composition of gut, vagina and skin. However, in some cases, Lactobacillus spp. have been implicated in bacteremia. The aim of the study was to examine the genomic and immunological properties of 16 clinical blood isolates of L. rhamnosus and to compare them to the well-studied L. rhamnosus probiotic strain GG. Blood cultures from bacteremic patients were collected at the Helsinki University Hospital laboratory in 2005–2011 and L. rhamnosus strains were isolated and characterized by genomic sequencing. The capacity of the L. rhamnosus strains to activate serum complement was studied using immunological assays for complement factor C3a and the terminal pathway complement complex (TCC). Binding of complement regulators factor H and C4bp was also determined using radioligand assays. Furthermore, the isolated strains were evaluated for their ability to aggregate platelets and to form biofilms in vitro. Genomic comparison between the clinical L. rhamnosus strains showed them to be clearly different from L. rhamnosus GG and to cluster in two distinct lineages. All L. rhamnosus strains activated complement in serum and none of them bound complement regulators. Four out of 16 clinical blood isolates induced platelet aggregation and/or formed more biofilms than L. rhamnosus GG, which did not display platelet aggregation activity nor showed strong biofilm formation. These findings suggest that clinical L. rhamnosus isolates show considerable heterogeneity but are clearly different from L. rhamnosus GG at the genomic level. All L. rhamnosus strains are still normally recognized by the human complement system.

Lactobacillus rhamnosus Endocarditis After Upper Endoscopy

Lactobacillus rhamnosus is commonly found in gastrointestinal flora and used in probiotics but is a rare human pathogen. We report a case of L. rhamnosus endocarditis following upper endoscopy in a frequent consumer of yogurt containing the organism, who required aortic and mitral valve replacement for cure.

Scientific Opinion on the update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA

EFSA is requested to assess the safety of a broad range of biological agents in the context of notification for market authorisation as sources of food and feed additives, food enzymes and plant protection products. The qualified presumption of safety (QPS) assessment was developed to provide a harmonised generic pre-assessment to support safety risk assessments performed by EFSA's scientific Panels. The safety of unambiguously defined biological agents (at the highest taxonomic unit appropriate for the purpose for which an application is intended), and the completeness of the body of knowledge are assessed. Identified safety concerns for a taxonomic unit are, where possible and reasonable in number, reflected as 'qualifications' in connection with a recommendation for a QPS status. The list of QPS recommended biological agents was reviewed and updated in the current opinion and therefore becomes the valid list. The 2016 update reviews previously assessed microorganisms including bacteria, yeasts and viruses used for plant protection purposes following an Extensive Literature Search strategy. The taxonomic units related to the new notifications received since the 2013 QPS opinion, were periodically evaluated for a QPS status and the results published as Statements of the BIOHAZ Panel. Carnobacterium divergens, Lactobacillus diolivorans, Microbacterium imperiale, Pasteuria nishizawae, Pediococcus parvulus, Bacillus flexus, Bacillus smithii, Xanthomonas campestris and Candida cylindracea were recommended for the QPS list. All taxonomic units previously recommended for the 2013 QPS list had their status reconfirmed as well their qualifications with the exception of Pasteuria nishizawae for which the qualification was removed. The exclusion of filamentous fungi and enterococci from the QPS evaluations was reconsidered but monitoring will be maintained and the status will be re-evaluated in the next QPS Opinion update. Evaluation of bacteriophages should remain as a case-by-case procedure and should not be considered for QPS status.

Impact of probiotics on necrotizing enterocolitis

A large number of randomized placebo-controlled clinical trials and cohort studies have demonstrated a decrease in the incidence of necrotizing enterocolitis with administration of probiotic microbes. These studies have prompted many neonatologists to adopt routine prophylactic administration of probiotics while others await more definitive studies and/or probiotic products with demonstrated purity and stable numbers of live organisms. Cross-contamination and inadequate sample size limit the value of further traditional placebo-controlled randomized controlled trials. Key areas for future research include mechanisms of protection, optimum probiotic species or strains (or combinations thereof) and duration of treatment, interactions between diet and the administered probiotic, and the influence of genetic polymorphisms in the mother and infant on probiotic response. Next generation probiotics selected based on bacterial genetics rather than ease of production and large cluster-randomized clinical trials hold great promise for NEC prevention.