A Novel Genetic Label for Detection of Specific Probiotic Lactic Acid Bacteria

A novel method for genetic labelling of specific lactic acid bacteria strains was developed. The approach implied the transformation of the hosts with a plasmid containing a heterologous DNA fragment. The sequence of a DNA fragment that has been used to label a variety of genetically modified (GM) soya was used to design a forward primer and three reverse primers yielding PCR products recognisable by their sizes. Stability of the recombinant plasmid in the transformed strains was studied by PCR, and the results varied significantly depending on the strain. To test the usefulness of the DNA label to study in vivo properties of probiotic bacteria, such as viability after transit through the digestive tract, mice were orally inoculated with a genetically-labelled Enterococcus faecium strain. Later, their faeces were aseptically collected and the genetically-labelled strain was detected among the colonies that grew on MRS agar.

Elvitegravir for the treatment of HIV infection

Advances in antiretroviral treatment have transformed HIV-1 infection from a deadly disease to a chronic one. Novel antiretroviral drugs have been approved for clinical use. In order to achieve long-term suppression of viremia, patients have to commit and take these drugs, or others approved in the future, for the rest of their lives. However, the emergence of multidrug-resistant mutants, along with the side effects of them, often results in the failure of therapy, so better treatment options are needed. Elvitegravir is a potent HIV integrase inhibitor with antiviral activity against wild-type and drug-resistant strains of HIV. In addition, elvitegravir can also inhibit the replication of several retroviruses and lentiviruses. Elvitegravir undergoes extensive primary metabolism by hepatic and intestinal cytochrome P450 3A (CYP3A) and secondary metabolism by UDP-glucuronosyltransferase 1-1 and 1-3 (UGT1A1/3). Although boosting it with a strong CYP3A inhibitor such as ritonavir substantially increases its plasma exposure and prolongs its elimination half-life, other combinations or even monotherapy could also be considered. Ritonavir-boosted elvitegravir requires once-daily administration of a low dose. As a stand-alone agent, elvitegravir will require twice-daily dosing to achieve effective viral reductions.

A food-grade system for production of pediocin PA-1 in nisin-producing and non-nisin-producing Lactococcus lactis strains: application to inhibit Listeria growth in a cheese model system

Food-grade heterologous production of pediocin PA-1 in nisin-producing and non-nisin-producing Lactococcus lactis strains, previously selected because of their technological properties for cheese making, was achieved. Plasmid pGA1, which contains the complete pediocin operon under the control of the strong P32 promoter and is devoid of any antibiotic marker, was introduced into L. lactis ESI 153 and L. lactis ESI 515 (Nis+). Transformation of L. lactis ESI 515 with pGA1 did not affect its ability to produce nisin. The antimicrobial activity of the pediocin-producing transformants on the survival of Listeria innocua SA1 during cheese ripening was also investigated. Cheeses were manufactured from milk inoculated with 1% of the lactic culture and with or without approximately 4 log CFU/ml of the Listeria strain. L. lactis ESI 153, L. lactis ESI 515, and their transformants (L. lactis GA1 and GA2, respectively) were used as starter cultures. At the end of the ripening period, counts of L. innocua in cheeses made with the bacteriocin-producing lactococcal strains were below 50 CFU/g in the L. lactis GA1 cheeses and below 25 CFU/g in the L. lactis GA2 ones, compared with 3.7 million CFU/g for the controls without nisin or pediocin production.

Differentiation of Enterococcus faecium from Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains by PCR and dot-blot hybridisation

Variations in length and sequence of the 16S/23S spacer region of Enterococcus faecium provided the basis for development of simple PCR and dot-blot hybridisation assays that enabled the differentiation of potentially probiotic Enterococcus faecium strains from Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Such assays may be useful for differentiation of yoghurt starter cultures and enterococcal strains when they are simultaneously present in probiotic food products.