Labeling quality and molecular characterization studies of products containing Lactobacillus spp. strains.

The objective of the study was to characterize at species level by phenotypic and different molecular methods the strains of Lactobacillus spp. used as constituents of five oral and four vaginal products. Susceptibilities to representative antibiotics were evaluated. In addition, total viable counts at mid and 3 months to deadline of shelf life, in the different formulations and the presence of eventual contaminant microorganisms were investigated.In all oral products the molecular characterization at species level of the strains of Lactobacillus spp. confirmed the strains stated on the label, except for one strain cited on the label as Lactobacillus casei, that our study characterized as Lactobacillus paracasei. In oral products total viable cell content complied with content claimed on the label. In three out four vaginal products (one product claimed "bacillo di Döderlein"), molecular characterization complied with the bacterial name stated on the label. Two vaginal products reported viable counts on the label that were confirmed by our study. The other vaginal products, which did not report bacterial counts on the label, showed a similar decrease of viable counts at different dates to deadline compared to the others. From all the tested products, contaminant microorganisms and acquired resistance to representative antibiotics by the probiotic strains were not detected.

Probiotics: overview of microbiological and immunological characteristics.

Over the last few years, probiotics (commercialized as food, dietary supplements of living bacteria or pharmaceuticals) have attracted the interest of scientists as well as consumers. Recent public interest in healthier lifestyles, together with the acceptance by physicians of nonmainstream therapies, has refocused attention on the role of human microbiota in the prevention and therapy of diseases. Modulation of the intestinal microbiota may be achieved by consuming living bacteria or by consuming a combination of probiotics and prebiotics. In addition, we are learning more about the biology of probiotic microorganisms, through sequencing their genomes, and the interactions of probiotics with human cells and with pathogenic bacteria. Results from well-conducted clinical studies help to increase the acceptance of probiotics for the treatment and prevention of selected diseases, both inside and outside the GI tract. Moreover, the use of selected probiotics for particular subject groups may provide more specific health effects. The medical profession is in an ideal position to guide the consumer towards appropriate prophylactic or therapeutic uses of probiotics in health or in specific disease states.

Identification and antibiotic susceptibility of bacterial isolates from probiotic products available in Italy.

This study was carried out to assay the bacterial viability and the probable contamination of a range of probiotic products available in Italy and to test the susceptibility of the isolates. Eleven dried food supplements and five fermented functional foods were examined using different isolation media under standardized cultivation conditions. The identification was made by conventional phenotypic characteristics and biochemical tests. Among isolates from the probiotic products antibiotic susceptibility was detected using the E-test (ABBiodisk). Our results demonstrate that nine food supplements and two fermented foods claimed species which could not be isolated, whereas potential pathogens (i.e. Micromonas micros) were isolated. Lactobacilli displayed species-dependent antibiotic resistance. Atypical resistance occurred for penicillin in Lactobacillus acidophilus and Lactobacillus bulgaricus and for erythromycin in Lactobacillus lactis and Lactobacillus salivarius. A broad range of MICs was observed for cephalosporins and fluroquinolones. Aminoglycosides had poor activity against Lactobacillus isolates. Two of the four isolates of Bifidobacterium exhibited high resistance to trimethroprim/sulfametoxazole and to fluoroquinolones. Our results suggest that some probiotic products claim species that cannot always be isolated, and are sometimes contaminated by potential pathogens. Moreover, the probable transferable erythromycin or penicillin resistance among the lactobacilli isolated should be taken into account.