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 removed 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

 

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