The effect of nonylphenol on the growth of Lactobacillus acidophilus and Bifidobacterium bifidum

Background and purpose: Nonylphenol (NP) is a well-known environmental hormone recognized as detrimental to the reproductive systems of aquatic animals and humans. The effect of NP on probiotics in the human gastrointestinal tract remains unclear. This study investigated the effect of NP on the growth of Lactobacillus acidophilus and Bifidobacterium bifidum. Methods: L. acidophilus and B. bifidum were grown in anaerobic cultures. Both strains were incubated with and without NP. The dose effects of NP on the growth of both probiotics were compared, and the effects of NP on the growth of L. acidophilus and B. bifidum in different concentrations were evaluated. Results: NP 5 to 10 mu g/mL inhibited the growth of L. acidophilus (p < 0.05), but was ineffective at 2.5 mu g/mL (p > 0.05). NP significantly inhibited the growth of B. bifidum in a dose-dependent manner (p < 0.05). NP inhibited the growth of different concentrations of L. acidophilus (6.25 x 10(4) to 2.5 x 10(5) colony-forming units [CFU]/mL) and B. bifidum (1.25 x 10(9) to 5.0 x 10(9) CFU/mL) [p < 0.05]. Conclusions: Growth of L. acidophilus and B. bifidum was inhibited by NP. This finding suggests that NP may interfere with normal gastrointestinal microbiota. This may alter immunomodulation in the intestinal mucosa and may be correlated with an increase in the incidence of allergic diseases or other gastrointestinal disorders.