The Safety of Probiotics

Division of Geographic Medicine and Infectious Diseases and Department of Medicine, Tufts-New England Medical Center, and Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
Clinical Infectious Diseases (Impact Factor: 8.89). 03/2008; 46 Suppl 2(Suppl 2):S104-11; discussion S144-51. DOI: 10.1086/523331
Source: PubMed


Probiotics are generally defined as microorganisms that, when consumed, generally confer a health benefit on humans. There
is considerable interest in probiotics for a variety of medical conditions, and millions of people around the world consume
probiotics daily for perceived health benefits. Lactobacilli, bifidobacteria, and lactococci have generally been regarded
as safe. There are 3 theoretical concerns regarding the safety of probiotics: (1) the occurrence of disease, such as bacteremia
or endocarditis; (2) toxic or metabolic effects on the gastrointestinal tract; and (3) the transfer of antibiotic resistance
in the gastrointestinal flora. In this review, the evidence for safety of the use of or the study of probiotics is examined.
Although there are rare cases of bacteremia or fungemia related to the use of probiotics, epidemiologic evidence suggests
no population increase in risk on the basis of usage data. There have been many controlled clinical trials on the use of probiotics
that demonstrate safe use. The use of probiotics in clinical trials should be accompanied by the use of a data-safety monitoring
board and by knowledge of the antimicrobial susceptibilities of the organism used.

    • "As mentioned before, another theoretical concern about probiotics are systemic infections because of their movement from the GI tract. Indeed, some reports demonstrated that probiotics rarely lead to bacteremia and fungemia (Snydman, 2008). Because the exact mechanisms of probiotics are not yet understood, safety of probiotic administration is not predictable . "
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    ABSTRACT: Probiotics are live microorganisms, conferring a health benefit on the host when administered in a sufficient amount. Generally, Lactobacilli, Bifidobacteria, and Saccharomyces are recognized as “Generally Regarded As Safe by the WHO.” However, further caution is needed to administer probiotics to patients with compromised immune systems, leaky gut, or critical illnesses. Different strains of probiotics have different safety profiles, which should be taken into account, and generalizations in relation to all probiotics should be avoided. Particularly, the safety of probiotics in an at-risk population should be categorized as strain-by-strain basis, dose and interaction with other strains and pathologic conditions.
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    • "included in lactic acid fermented foods as potential vehicles of spread of antibiotic resistance determinants have received increasing attention in recent years. The risks are associated with potential transfer of antibiotic resistance within the gastrointestinal tract from commensal or probiotic bacteria to other bacteria or potential pathogens, thus impairing successful antibiotic treatment of common microbial infections (Klein et al., 2000;Snydman, 2008). The antibiotic resistance genes can be transferred horizontally via mobile elements (plasmids, transposons and integrons) which are responsible for intra-and inter-species transfer of genetic material (vanReenen & Dicks, 2011). "
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    ABSTRACT: Bacteria belonging to the genus Lactobacillus are used as starter cultures or that develop naturally as fermenting microbiota in the production of various foods. On the detrimental side, lactobacilli may act as reservoir of antibiotic resistance genes, which can spread to commensal bacteria in humans or animals, or to food-associated pathogens. In the last decade, advances in molecular biology and in genome sequencing have provided more information on antibiotic resistances in foodborne bacteria. The aim of this review was to consider and provide an up-to-date status on phenotypic and genotypic antibiotic resistance profiles in Lactobacillus species from fermented foods and also to highlight new information on the distribution of glycopeptide and chloramphenicol resistance genes in Lactobacillus genomes. In silico screening of vanZ (vancomycin resistance) and cat (chloramphenicol resistance)-like sequences in Lactobacillus species isolated from fermented foods revealed for the first time the occurrence of vanZ and cat genes in Lactobacillus species being highly conserved genes in the chromosome of each species, presumably non-transferable. Further studies involving genome sequences of Lactobacillus isolated from fermented foods, especially those relying on spontaneous fermentation, is crucial to increase knowledge on the potential presence and spread of antibiotic resistance genes via the food route.
    Full-text · Article · Sep 2015 · Food Research International
    • "Lactobacilli, bifidobacteria and lactococci are generally regarded as safe because of their long history of use in the food and dairy industries [16]. Although rare cases of bacteraemia or fungaemia were reported, there is no evidence from population-based studies of any increased risk of bacteraemia or endocarditis due to probiotics [17] [18]. "
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    ABSTRACT: Meticillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant micro-organism and is the principal nosocomial pathogen worldwide. Following initial in vitro experiments demonstrating that Lactobacillus acidophilus CL1285(®) and Lactobacillus casei LBC80R(®) commercial strains exhibit antibacterial activity against clinical MRSA isolates, we conducted a literature search to find any evidence of probiotic efficacy in decolonisation or treatment of S. aureus infection. As summarised below, many strains of lactobacilli and bifidobacteria isolated from a variety of sources inhibited the growth of S. aureus and clinical isolates of MRSA in vitro. The most active strains were Lactobacillus reuteri, Lactobacillus rhamnosus GG, Propionibacterium freudenreichii, Propionibacterium acnes, Lactobacillus paracasei, L. acidophilus, L. casei, Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus fermentum and Lactococcus lactis. Their effects were mediated both by direct cell competitive exclusion as well as production of acids or bacteriocin-like inhibitors. L. acidophilus also inhibited S. aureus biofilm formation and lipase production. In vitro antimicrobial activity did not necessarily assure efficacy in vivo in animal infectious models, e.g. S. aureus 8325-4 was most sensitive in vitro to L. acidophilus, whilst in vivo Bifidobacterium bifidum best inhibited experimental intravaginal staphylococcosis in mice. On the other hand, L. plantarum, which showed the highest inhibition activity against S. aureus in vitro, was also very effective topically in preventing skin wound infection with S. aureus in mice. Very few clinical data were found on the interactions between probiotics and MRSA, but the few identified clinical cases pointed to the feasibility of elimination or reduction of MRSA colonisation with probiotic use.
    No preview · Article · Sep 2013 · International journal of antimicrobial agents
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