Microbial Diseases of the Urinary and Reproductive Systems
Introduction
The urinary system regultes teh chemical composition of the blood and excretes nitrogenous waste.
The reproductive system produces gametes for reproduction and, in the female, supports the growing embryo.
Microbial diseases of these systems can result from infection from an outside source or from opportunistic infection by members of the normal microbiota.
Structure and Function of the Urinary System
Urine is transported from the kidneys through ureters to the urinary bladder and is eliminated through the urethra.
Valves prevent urine from flowing back to the urinary bladder and kidneys.
The flushing action of urine and the acidity of normal urine have some antimicrobial value.
Structure and Function of the Reproductive Systems
The female reproductive system consists of two ovaries, two uterine tubes, the uterus, the cervix, the vagina, and the external genitals.
The male reproductive system consists of two testes, ducts, accessory glands, and the penis; seminal fluid leaves the male body through the urethra.
Diseases of the Urinary System
Bacterial Diseases of the Urinary System
Urethritis, cystitis, and ureteritis are terms describing inflammations of tissues of the lower urinary tract.
Pyelonephritis can result from lower urinary tract infections or from systemic bacterial infections.
Opportunistic gram-negative bacteria from the intestines, Candida albicans, Staphylococcus, and Streptococcus often cause urinary tract infections.
Nosocomial infections following catheterization occur in the urinary system (35% of all nosocomial infections occur in the urinary tract). E. coli causes more than half of these infections.
Predisposing Factors include nervous system disorders, toxemia, diabetes mellitus, and obstructions to urine flow.
More than 100,000 bacteria per ml of urine or 100 coliforms per ml of urine indicates an infection.
Treatment of urinary tract infections depends on the isolation and antibiotic sensitivity testing of the causative agents.
Cystitis
Inflammation of the urinary bladder, or cystitis, is common in females because of a short urethra.
Contributing factors include careless personal hygiene, sexual intercourse, and urinary tract infections.
Gram-negative rods are the most common cause.
Symptoms are dysuria and pyuria.
Treatment - Antibiotics - type depends on the etiologic agent.
Pyelonephritis
Inflammation of the kidneys is usually a complication of a lower urinary tract infection and involves nephrons and renal pelvis.
Etiologic agent is usually Escherichia coli (75%).
Chronic condition causes formation of scar tissue.
Treatment: Antibiotics
Leptospirosis
The disease is caused by the spirochete Leptospira interrogans and is transmitted to humans by urine-contaminated water.
Leptospirosis is characterized by chills, fever, headache, jaundice.
Diagnosis is based on isolation and identification by serological tests.
Treatment is usually with penicillin, but it is often not satisfactory.
Diseasesof the Reproductive Systems
Bacterial Diseases of the Reproductive Systems
Most diseases of the reproductive system are suxually transmitted diseases (STDs).
Most STDs can be prevented by the use of condoms and are treated with antibiotics.
Gonorrhea
Gonorrhea is caused by the gram-negative diplococcus Neisseria gonorrhoeae.
Gonorrhea is the most common reportable communicable disease in the US.
Attaches to mucosal cells of the oral-pharyngeal area, genitals, eyes, and rectum by fimbrae.
Females may be asymptomatic until the infection spreads to the uterus and uterine tubes. Symptoms in males are painful urination and pus discharge.
Complications in males are blockage of the urethra and sterility. Complications in females include blockage of the uterine tubes, sterility, pelvic inflammatory disease. Complications affecting both genders are endocarditis, meningitis, and arthritis.
Opthamlia neonatorum is an eye infectin acquired by infants during passage through the birth canal of an infected mother.
Diagnosis is by culture and identification using a FA procedure or DNA probe.Treatment is penicillin although penicillinase producing strains exist. Ceftriaxone is the drug of choice. Spectinomycin or ciprofloxacin may be used.
Nongonococcal Urethritis
Any inflammation of the urethra not caused by Neisseria gonorrhoeae.
Chlamydia trachomatis is the most common cause.
40 % of the cases are sexually transmitted.
Symptoms are often mild or lacking, although salpingitis (uterine tube inflammation) and sterility may occur.
Can be transmitted to infants’ eyes at birth.
Other causes of NGU include Ureaplasma urealyticum and Mycoplasma hominis.
Treatment of NGU is with tetracycline or erythromycin.
Pelvic Inflammatory Disease (PID)
Extensive bacterial infection of the female pelvic organs, especially of the reproductive system, is called pelvic inflammatory disease (PID).
PID is caused by N. gonorrhoeae, Chlamydia trachomatis, and other bacteria that gain access to the uterine tubes.
Syphilis
Caused by the gram-negative spirochete Treponema pallidum, which has never been cultured in vitro. Cultures are grown in rabbits or cell cultures.
Transmitted by direct contact although T. pallidum can penetrate mucous membranes and breaks in the skin.
The primary lesion is a small, hard based chancre at the site of the infection. The bacteria invade the blood and lymphatic system and the chancre spontaneously heals.
The secondary stage is marked by a widely disseminated rash (containing spirochetes) on skin and mucous membranes.
There is a latent period after the secondary lesions heal.
At least 10 years after the secondary lesions heal tertiary lesions called gummas can appear on many organs.
Congenital syphilis, resulting from the organism crossing the placenta during the latent period, can cause neurological damage in the newborn.
Diagnosis is by darkfield microscopy, VDRL or RPR, andFTA-ABS.
Treatment is penicillin.
Lymphogranuloma venereum
Caused by Chlamydia trachomatis and is primarily a disease of tropical and subtropical areas.
The initial lesion on the genitals and heals without scarring.
The bacteria spread via the lymph and cause enlargement of the lymph nodes, obstruction of lymph vessels, and swelling of the external genitals.
Organisms are isolated and identified from pus taken from lymph vessels.
Treatment is tetracycline or erythromycin.
Chancroid (Soft Chancre)
Chancroid, a swollen painful ulcer on the mucous membranes of the genitals or mouth, is caused by the gram-negative rod Haemophilus ducreyi.
Treatment is tetracycline or trimethoprim-sulfamethoxazole.
Bacterial Vaginosis
Vaginosis is an infection without inflammation caused by Gardnerella vaginalis (Gardnerella vaginitis)
Gardnerella vaginalis is an opportunistic pathogen, the disease occurs when pH is 5 to 6. It is characterized by frothy discharge with a fishy odor and the presence of clue cells.
Treatment of Gardnerella vaginitis is metronidazole.
Other causes of vaginitis include Candida albicans and Trichomonas vaginalis.
Viral Diseases of the Reproductive System
Genital Herpes
Caused by herpes simplex virus, usually type 2.
Symptoms are painful urination, genital irritation, and fluid filled vesicles.
Neonatal herpes is contracted during fetal development or birth. It can cause neurological damage and can be fatal.
The virus may become latent in neurons; vesicles may reappear after trauma, hormonal changes, and UV light exposure.
The infection is associated with cervical cancer.
Treatment is acyclovir (not curative).
Genital Warts
Caused by papillomaviruses (Papovaviruses).
Associated with cervical cancer, especially when co-infected with HSV-2.
AIDS
Acquired virally induced immunodeficiency, caused by HIV retrovirus.
No treatment is effective, it is usually fatal.
Fungal Diseases of the Reproductive System
Candidiasis
Candida albicans causes NGU in males and vulvovaginal candidiasis in females.
Vulvovaginal candidiasis is characterized by itching lesions and irritation.
Predisposing factors are pregnancy, diabetes, tumors, and broad spectrum antibacterial therapy.
Diagnosis is based on observation, isolation and identification of the fungus.
Treatment is clotrimazole or miconazole.
Protozoan Diseases of the Reproductive System
Trichomoniasis
Caused by Trichomonas vaginalis, occurs when pH of the vagina is increased.
May be sexually transmitted or an opportunistic infection.
Diagnosis is based on observation of the protozoan in purulent discharges from the site of infection.
Treatment is metronidazole.