Introduction And Literature Review
1.1 Introduction
Bacteriocins are defined as ribosomally synthesized antimicrobial peptides which are generally active against microorganisms closely related to the producer strain (Turovskiy et al., 2009). The term bacteriocin-like substance is applied to antagonistic substances that arenot completely defined or do not fit the typical criteria of bacteriocins. They have been reported to inhibit a wide range of both Gram-positive and Gram-negative bacteria as well as fungi (Ocanaet al., 1999). They function mainly by creating pores across bacterial cell membrane.
Lactobacillus species are non-pathogenic Gram positive rods that are predominantlyisolated from the vagina of healthy premenopausal women (McClelland et al., 2009). In this environment, they exert a protective effect against pathogenic microorganisms by using different mechanisms such as production of antimicrobial agents, which include organic acids, hydrogen peroxide, and bacteriocins (Ocana et al., 1999).
The protective role of Lactobacilli in the vagina becomes evident when their concentrations drop, which may be as a result of the use of antibiotics or in an immunocompromised host, in which case the hydrogen ion concentration (pH) of their environment tends to increase. This, in turn, favors colonization by intestinal bacteria and the overgrowth of microorganisms indigenous to the vagina but usually present in low numbers. These include the etiological agents of bacterial vaginosis, yeast vaginosis, trichomoniasis, and the potential pathogen Streptococcus agalactiae (Rebeca et al., 2008).
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