Lactobacillus crispatus is a common, rod-shaped species of genus Lactobacillus and is a hydrogen peroxide (H2O2) producing beneficial micro biota species located in both the vagina, through vaginal discharge, and the vertebrate gastrointestinal. The strain CTV-05 is used as a probiotic that can be used by premenopausal and postmenopausal women that experience recurrent urinary tract infections. It is being evaluated specifically for the prevention and treatment of bacterial vaginosis, which is characterized by the absence of lactobacillus flora, also known as Lactobacillus acidophilus; which plays a large role in protecting the host from infection.
It is a species in the phylum Firmicutes, in the class Bacilli, in the order Lactobacillales, in the family Lactobacillaceae and the genus Lactobaccillus. It is one of one hundred twenty two other species identified within the genus.
The genome of Lactobacillus crispatus strain ST1 consists of about 2,043,161 nucleotides and encodes 2,024 proteins, 76 RNA genes  and has a circular chromosomal shape. ST1 was originally isolated from chicken. Other strains isolated from human vaginas encode between 1,839 (EM-LC1) and 2,699 proteins (strain FB077-07).
The strain of Lactobacillus crispastus was originally isolated from a pouch in chickens gullet and is considered to be one of the strongest H2O2-producing lactobacilli. Like many other Lactobacillus species, it can be severely altered by changes to the immune system, hormone levels and from the use of antimicrobials. Lactobacillus crispatus is a normal inhabitant of the lower reproductive tract in healthy women.
CTV-05 gelatin suppository capsules are inserted into the vagina as a probiotic that can help maintain healthy flora. Studies have shown that L. crispastus CTV-05 effectively colonized the vagina and helped prevent and treat recurrent bacterial vaginosis and other genital infections. Scientists have stated that evidence from clinical trials proves that these probiotics will safely and effectively treat bacterial vaginosis if used alone or alongside an antibiotic treatment if an infection had already arisen.
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