Chapter 26: Microbial Diseases of the Urinary & Reproductive System

Microbial Diseases of the Urinary & Reproductive System opens by outlining the anatomy and defenses of these systems—such as urine flow, acidic vaginal pH, and mucosal immune factors like IgA. Normal microbiota are limited in the upper urinary tract but present in the lower urethra and vagina, especially Lactobacillus in females, which helps maintain acidic conditions. The chapter explores urinary tract infections (UTIs), which are more common in females due to anatomical differences. Cystitis (bladder infection), typically caused by Escherichia coli and Staphylococcus saprophyticus, presents with dysuria and urgency. Pyelonephritis, a kidney infection, can result from untreated cystitis and may cause fever and flank pain. Diagnosis involves urine cultures and leukocyte esterase tests. For the reproductive system, the chapter covers both bacterial and viral sexually transmitted infections (STIs). Gonorrhea, caused by Neisseria gonorrhoeae, is a common bacterial STI that may lead to pelvic inflammatory disease (PID) and infertility. Nongonococcal urethritis (NGU) is most often caused by Chlamydia trachomatis, which can also cause PID, ectopic pregnancy, and neonatal eye infections. Syphilis, caused by Treponema pallidum, progresses through primary (chancre), secondary (rash), latent, and tertiary stages—potentially affecting the brain and heart. Other bacterial STIs include Haemophilus ducreyi (chancroid) and Gardnerella vaginalis (bacterial vaginosis). Viral infections include genital herpes (HSV-2), characterized by painful vesicles and latency in nerve cells; genital warts caused by human papillomavirus (HPV), which is associated with cervical and penile cancer; and HIV/AIDS, which impacts the immune system broadly and is covered in more depth elsewhere. The importance of vaccination for HPV and antiviral therapy for HSV is emphasized. Candidiasis (Candida albicans) is the most common fungal vaginal infection, often linked to antibiotic use or immune suppression. Protozoan infections include trichomoniasis, caused by Trichomonas vaginalis, which can be asymptomatic or produce greenish discharge and irritation. Throughout the chapter, prevention strategies such as safe sex practices, early diagnosis, and vaccination are emphasized as critical tools in reducing the spread and impact of these infections.