Candidiasis is a fungal infection caused by opportunistic species of Candida. It can affect various anatomical sites, including the skin, oral cavity, nails, and genitourinary tract. Among its forms, vaginal candidiasis is the most common type of mucosal infection. It typically results from the overgrowth of Candida albicans in the vaginal mucosa. Under normal conditions, C. albicans exists as a commensal organism within the vaginal microbiota, regulated by the dominance of lactobacilli, which...

Sexually transmitted infections (STIs) are diseases transmitted primarily through unsafe sexual interactions. Bacteria, viruses, or parasites cause them and can result in severe health complications if untreated.ChlamydiaThe bacterium Chlamydia trachomatis is responsible for the disease Chlamydia, the most common STI in the United States. This peculiar pathogen requires human cells to reproduce, residing intracellularly. The initial infection often goes unnoticed because it typically does not...

Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...

Skin is the first line of defense and encounters a variety of microbes. Some pathogenic strains are often the cause of a broad range of infections of the skin and other body systems. These conditions can affect people of all ages and may have different causes, including genetic factors, infections, autoimmune reactions, environmental factors, and lifestyle choices.
Gram-positive Staphylococcus spp. and Streptococcus spp. are responsible for many of the most common skin infections. However, many...

Trichomonas vaginalis is a flagellated protozoan parasite and the causative agent of trichomoniasis, one of the most prevalent non-viral sexually transmitted infections in the United States. This extracellular parasite primarily colonizes the lower genitourinary tract in women—particularly the vagina—and in men, the urethra and prostate. Its structural and functional adaptations enable its survival, motility, and pathogenicity within the host environment.Structural Features and Host EntryT.

Phylum Ascomycota, a major division within the subkingdom Dikarya, comprises a diverse range of fungal species, including both unicellular yeasts and filamentous molds such as Aspergillus and Penicillium. These fungi thrive in a variety of habitats, from aquatic ecosystems to terrestrial environments, playing crucial ecological and economic roles.Morphology and ReproductionThe defining characteristic of Ascomycetes, commonly referred to as sac fungi, is the ascus—a sac-like structure that...