Until recently, there has never been any question about probiotic safety.
However, there have been rare instances of probiotic bacteria being implicated in the deaths of immunocompromised people (HIV or on some chemotherapy drugs) so in 2003 a workshop consisting of experts from clinical practice, microbiology, intestinal microecology, pathogenicity, nutrition, toxicology, and public health reviewed the cases to answer any question of probiotic safety.
They found that both Lactobacilli and bifidobacteria are "extremely rare causes of infection in humans" and that the usual benign effect of these two friendly bacteria extended across all ages groups – young and old - and also to immunocompromised individuals.1
It was agreed that although enterococci is regularly taken by many people with only positive effects it did pose a greater threat than other lactic acid bacteria such as Lactobacilli and bifidobacteria.
In summary, the findings from this study on probiotic safety stated: "Immunocompromised patients generally are more vulnerable to infection with pathogens and have a higher incidence of opportunistic infections.
However, there is no published evidence that consumption of probiotics that contain lactobacilli or bifidobacteria increases the risk of opportunistic infection among such individuals. In addition, 2 clinical studies have been conducted to assess the safety of probiotics in small groups of specific immunocompromised patients (e.g., patients with HIV infection), and the findings of these studies support the safety of probiotics consumed by such groups."1
This above statement cited the 1998 study "Safety and tolerance of Lactobacillus reuteri supplementation to a population infected with the human immunodeficiency virus"2 and the 2000 "Probiotics and immune response" study in support of these claims.
It seems as if the rare cases of infection with either of these two bacteria have been when “invasive” procedures that involve the gastrointestinal tract (which naturally has a large population of these two bacteria) are combined with "chronic immunosuppressive and antibiotic therapy".1
Good bacteria such as Lactobacilli and bifidobacteria are in many of the foods we eat, particularly fermented foods such as yogurt, cheese, sauerkraut, and fermented vegetables. In these traditionally fermented foods they stop the growth of pathogenic bacteria and that is one of the roles they play in our bodies. They are a natural and health-enhancing part of our diet.
In healthy people Lactobacilli and bifidobacteria will be present in the mouth, the gastrointestinal tract and the vagina where they are often the most common bacteria present.
There has been a case of Lactobacillus rhamnosus sepsis in a patient with corticoid immunosuppression in association with live yogurt biotherapy4 and a case of endocarditis4 so patients who are immunosuppressed or have preexisting heart valve disease should avoid probiotic preparations containing L rhamnosus.
For those who love figures, the estimated numbers of colony forming units of helpful bacteria in those area are; oral cavity 103?104 cfu/g, the ileum 103?107 cfu/g, and the colon (104?108 cfu/g.1 So we have evolved to life alongside of (or outside of!) the many different strains of probiotic bacteria.
So if you have HIV, whilst caution and commonsense should be used when evaluating the need to take probiotic supplements (if you eat a healthy diet you will already be taking in probiotic bacteria), it does seem as if probiotics containing Lactobacilli and bifidobacteria are probably safe whilst entercoccus strains should be avoided.
Discuss probiotic safety fully with your doctor.
1. S. P. Borriello, W. P Hammes, W. Holzapfel, P. Marteau, J. Schrezenmeir, M. Vaara, V. Valtonen. Safety of Probiotics That Contain Lactobacilli or Bifidobacteria. Clinical Infectious Diseases 2003;36:775?780.
2. Wolf BW, Wheeler KB, Ataya, DG, Garleb KA. Safety and tolerance of Lactobacillus reuteri supplementation to a population infected with the human immunodeficiency virus. Food Chem Toxicol 1998; 36:1085?94.
3. Cunningham-Rundles S, Ahrné S, Bengmark S, et al. Probiotics and immune response. Am J Gastroenterol 2000; 95:S22?5.
4. M. Vancanneyt, G. Huys, K. Lefebvre, V. Vankerckhoven, H. Goossens, J. Swings. ntraspecific Genotypic Characterization of Lactobacillus rhamnosus Strains Intended for Probiotic Use and Isolates of Human Origin. Appl Environ Microbiol. 2006 August; 72(8): 5376–5383.doi: 10.1128/AEM.00091-06.