The human vagina is a complex and dynamic ecosystem containing an abundance of microorganisms. In women of childbearing age, this system is dominated by Lactobacillus spp. In the present work, seventeen newly isolated vaginal strains were identified by 16S rDNA sequencing and were investigated for their antimicrobial properties. Twelve of the isolated Lactobacillus strains showed activity against one or more microorganisms. Six and five of them produced substances that inhibited the growth of two different Klebsiella strains and Staphylococcus aureus, respectively. Two lactobacilli strains were active against an Escherichia coli strain, one isolate was active against an Enterococus faecalis strain and another lactobacilli strain showed antimicrobial activity against a Candida parapsilosis strain. The nature of the active compounds was additionally studied, and the presence of bacteriocin-like substances was proved. The genes related to the bacteriocin production in three of the newly isolated strains were identified and sequenced. The presence of gassericin A operon in the genome of the species Lactobacillus crispatus was described for the first time. The presence of antimicrobial activity contributes to their possible use as potential probiotic strains after further research.

In spite that lactic acid bacteria (LAB) are used for production of fermented foods and drinks for millennia, their ability to grow using starch as a sole carbon source was noticed by the scientists in the last 30 years. A number of amylolytic LAB (ALAB) strains were isolated and several detailed investigations of biochemical and genetic basis of starch hydrolysis were performed. The purpose of this review is to summarize for the first time the available data about the starch-modifying enzymes in ALAB. The most important amylolytic representatives of the genera Lactobacillus, Lactococcus, Streptococcus, Pediococcus, Carnobacterium, and Weissella are described. Amino acid sequences, corresponding to ALAB amylase enzymes are compared and some features of the gene expression are analyzed. The possible application of ALAB strains for direct production of lactic acid from starch, as well as their participation in food manufacturing is discussed.

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Lactobacilli play an important role in maintaining the vaginal health of women. The development of suitable bacterial replacement therapies for the treatment of vaginosis requires knowledge of the vaginal lactobacilli species representation. The aim of this study was to identify at the species level vaginal Lactobacillus isolates obtained from Bulgarian women in childbearing age by using different molecular methods. Twenty-two strains of lactobacilli isolated from vaginal samples were identified and grouped according to their genetic relatedness. A combined approach, which included amplified ribosomal DNA restriction analysis (ARDRA), ribotyping and polymerase chain reaction (PCR) with species-specific oligonucleotide primers was applied. All vaginal isolates were grouped into 5 clusters in comparison with a set of 21 reference strains based on the initial ARDRA results, which was then confirmed by ribotyping. Finally, the strains were subjected to PCR analysis with eight different species-specific primer pairs, which allowed most of them to be classified as belonging to one of the following species: Lactobacillus crispatus, Lactobacillus fermentum, Lactobacillus gasseri, Lactobacillus helveticus and Lactobacillus plantarum. In conclusion, this study suggests that the most straightforward identification strategy for vaginal lactobacilli would be grouping by ARDRA or ribotyping, followed by PCR specific primers identification at species level.