Chapter 23
Microbial Diseases of the Urinary and Reproductive System
STRUCTURES OF THE URINARY SYSTEM
• Components of the urinary system
– Kidneys
• Remove waste from the blood and excrete them in urine
• Nephrons are the functional unit of the kidneys
– Responsible for filtering the blood to form urine
– Ureters- urine travels to the urinary bladder
– Urinary bladder-stores urine until it can be eliminated
– Urethra-site of urine excretion
Normal Microbiota of the Urinary and Reproductive System
• Urethra
– Colonized by some microorganisms
– Primary species include Lactobacillus and Staphylococcus
• Remainder of the urinary organs are sterile
• Male reproductive system
– The regions above the prostate are sterile
• Female reproductive system
– The vagina is colonized by various microorganisms depending on hormone levels (Lactobacillus, corynebacteria, cocci...)
–
BACTERIAL DISEASES OF THE URINARY SYSTEM
• Examples of bacterial diseases of the urinary system
– Bacterial urinary tract infections - Cystitis
– Leptospirosis
– Streptococcal acute glomerulonephritis
Cystitis
• Causative agents: E. coli, Klebsiella, Proteus, and Pseudomonas.
• Portal of entry: Urethra - often by self-inoculation with fecal bacteria
• Females more susceptible - due to short urethra that is close to the anus
• Signs/Symptoms: Frequent, urgent and painful urination; urine may be cloudy
• Diagnosis: Analysis of urine
• Treatment: Antimicrobial drugs
Pyelonephritis
• If cystitis not treated – progresses to Pyelonephritis- inflammation of kidneys, back pain
• Causative agent: E. coli
• Bacteremia
• Potentially life-threatening
• Treatment: intravenous antibiotics
Leptospirosis
• Causative agent: Leptospira interrogans, a spiral bacterium
• Common disease of domestic and wild animals (dogs and cats)
• Humans contract the disease via urine-contaminated water
• Portal of entry: small abrasions on the skin, mucous of the upper digestive system
• Symptoms:
– 1st episode- headache, muscular ache, chills
– 2nd episode – kidney failure
• Diagnosis: serological tests
• Antibiotic treatment in a later stage not effective
•
DISEASES OF THE REPRODUCTIVE SYSTEM
(Sexually Transmitted Diseases)
• Types of STDs
• Bacterial STDs
• Viral STDs
• Protozoan STDs
•
BACTERIAL SEXUALLY TRANSMITTED DISEASES
• Bacteria are a common cause of STDs
• Bacteria causing STDs survive poorly on inanimate objects and are thus transmitted via sexual intercourse
Gonorrhea
• Causative agent: Neisseria gonorrheae
• Diplococci are attached to epithelial cells by fimbriae.
• The infection is followed by inflammation
• Symptoms in males: painful urination and discharge of pus (few days after infection).
• Females are asymptomatic (in most cases). (Abdominal pain as the result of pelvic inflammatory disease)
• Possible complications (if not treated)
– in both males and females:
• gonorrheal endocarditis, gonorrheal meningitis, gonorrheal arthritis, gonorrheal infection of eyes and pharynx.
– in males:
• blockage of urethra and sperm carrying tube (sterility).
– in females:
• ophtalmia neonatorum – blindness caused by infection of infants during the birth.
• Treatment: Penicillin, ciprofloxacin, cephalosporins (high rate of resistant strains)
• There is no adaptive immunity
•
Pelvic Inflammatory Disease (PID) – Women Only
• Cause: Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma hominis (rarely)
• Untreated PID can cause ectopic pregnancy or sterility
• Signs/Symptoms: Inflammation of uterine tubes, fever, abdominal pain
• Incubation period: Months to years after infection
• Treatment: cephalosporin
Syphilis
• Causative agent - Treponema pallidum, Gr-spirochete. Cannot be grown on artificial media.
• Transmitted by sexual contact
– Can also be transmitted from mother to fetus
• Incubation is between 2 weeks to several months
The disease has several stages
Primary stage
• Soft chancre – small lesions on the skin in the site of infection
• 10-90 days after infection
• They are painless and later disappear
• The bacteria enter the bloodstream
Secondary stage
• Several weeks after the primary stage - Skin rashes and lesions (contain bacteria), infection by non-sexual contact is possible
• The symptoms disappear and the disease remains latent for 2-4 years (non-infectious stage)
Tertiary stage
• Primary and secondary syphilis are not disabling – if not treated progresses to the 3rd stage
• Lesions called gummas (rubbery thickening of the skin or internal organs) – not very infectious
• Organs affected - cardiovascular system, and brain resulting in personality change, blindness, and seizure
Diagnosis of primary, secondary, and congenital syphilis: Presence of specific antibody against T. pallidum
Treatment Benzathin penicillin – long lasting, remains in the body for 2 weeks
Congenital Syphilis
• Occurs when a child is born to a mother with secondary or tertiary syphilis
• Some infants have symptoms at birth, but most develop symptoms later
Chlamydial infections
• Chlamydia is the most frequently reported bacterial STD in the United States
• Known as a "silent" disease because about three quarters of infected women and about half of infected men have no symptoms
• Symptoms in women,
– the bacteria initially infect the cervix and the urethra; might have an abnormal vaginal discharge or a burning sensation when urinating
– If not treated – pelvic inflammatory disease
• Symptoms in men
– discharge from the penis or a burning sensation when urinating
Lymphogranuloma venereum
• Causative agent: Chlamidia trichomatis, specific serovars
• Symptoms:
– Small painless ulcer on genitalia
– Swelling and redness of the skin in the groin area
– Swollen groin lymph nodes on one or both sides
• Common in Central and South America
VIRAL DISEASES OF THE REPRODUCTIVE SYSTEM
Genital Herpes
• Causative agent: Herpes simplex virus type 2
• Symptoms: (one week after infection) Vesicles appear on the skin of genital organs, painful urination. Vesicles disappear in 2 weeks.
• Herpesvirus kills epithelial cells at infection site
– Blisters may form at sites far from initial infection site
• Virus remains in a latent state in nerve cells. Reactivation of a virus can happen every 3-4 months
• There is no cure for genital herpes. Acyclovir alleviates the symptoms.
• Valacyclovir if taken daily reduces sexual transmission
FUNGAL DISEASES OF THE REPRODUCTIVE SYSTEM
Candidiasis – vaginal infection
• Causative agent: Candida albicans
• Opportunistic overgrowth when the competing (normal) microbiota is supressed
• Predisposing factors: diabetes and antibiotic therapy
PROTOZOAN DISEASE OF THE REPRODUCTIVE SYSTEMS
Trichomoniasis
• Causative agent: Trichomonas vaginalis – anaerobic protozoan
• Inhabitant of vagina and urethra in males
• Males have no symptoms of infection
• Symptoms in female: Irritation and itching with the discharge
• Treatment: metranidazol – administered to both partners