Probiotics may be unsafe in infants allergic to cow's milk

Abstract

Differences in the intestinal microflora of atopic and nonatopic infants have been shown; atopic children have fewer bifidobacteria and lactobacilli (1–3). Beneficial immunoregulatory effects of probiotic flora have been confirmed by preventive and therapeutic studies with probiotics in infants at high risk of atopy and in those presenting with cow’s milk allergy (CMA) and atopic eczema/dermatitis syndrome (AEDS) (3, 4). We report a case supporting the hypothesis that residual milk proteins at risk of reactogenicity may be present in different probiotic brands that are marketed as health supplement products. A 11-month-old infant, with AEDS and CMA was fed an aminoacid formula (Neocate ; SHS International Ltd, Liverpool, UK). He presented with Escherichia coli colitis, so a probiotic (Bacilor ; Lab Lyocentre, Aurillac, France) was prescribed. Within 15 min, he presented with generalized erythema and laryngeal discomfort. A prick-test to Bacilor was positive, as was a prick-test to milk (Table 1). Three other children, aged from 3 to 10 years, with persistent milk allergy were tested to three probiotic brands: Bacilor , Imgalt (Lab Jaldes, Gigean, France) and Ditopy (Lab Ducray, Boulogne, France). The prick-tests were positive to Bacilor and Imgalt (Table 1). Bacilor contains only Lactobacillus casei, of the rhamnosus variety, Imgalt also has L. rhamnosus, L. acidophilus, Bifidobacterium bifidum and B. longum, Ditopy contains L. rhamnosus and L. acidophilus. The manufacturers of these preparations were questioned about the medium used for the growth of these strains: the medium used for Bacilor and Imgalt flora includes lactoserum proteins and casein. No control tests for residual milk proteins are carried out on thesemedicinal products. The culture medium of Ditopy flora is hydrolyzed soy protein. The immediate clinical reaction in the infant, as well as positive-prick tests in these four children, support the hypothesis of residual milk proteins, the level of contamination being clinically relevant in somemilk allergic infants, at risk of anaphylaxis (5). Despite previous encouraging results, therapeutic results of probiotics were not particularly marked in a recent study (6, 7). No information was provided about the culture medium. In the event of marked allergy to milk proteins, ingestion of probiotics containing small amounts of residual milk proteins could explain sustained AEDS.