Microbiology 6e

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Chapter 20 Urogenital and Sexually Transmitted
Diseases
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Components and Functions of the Urinary System

• The urinary system consists of paired kidneys and
  ureters, the urinary bladder, and the urethra
• Each day the kidneys filter 200 L of fluid from
  bloodstream
• Allows wastes and excess ions to leave in urine
  and returns needed substances to bloodstream
• Regulate the blood volume and chemical make-up
• Metabolize vitamin D
• Act as endocrine gland
• Produce renin- functions in blood pressure
  regulation
• Produce erythropoietin stimulates RBC formation

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Urinary System Structures
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Structures of the Kidney
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Nephron functional unit of kidney

• Each kidney contains over 1 million nephrons and
  thousands of collecting ducts
• Each nephron consists of
• Glomerulus tuft of capillaries encircled by
  capsule
• Proximal convoluted tubule drains filtrate from
  renal corpuscle
• Loop of Henle has descending and ascending arm
• Dips down deep into medulla region
• Distal convoluted tubule empties into
  collecting duct which deliver urine to the minor
  calyces

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Flow of Urine Out of a System

• In a nephron, the fluid portion of the blood is
  filtered from the glomerulus, a coiled cluster of
  capillaries, to the kidney tubules
• Beginning with the renal cortex, nephrons remove
  solutes and water from the blood.
• As these materials pass through the renal
  medulla water, salts, and sugars pass back into
  the blood.

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• Urine, the wastes remaining in the kidney
  tubules, pass through collecting ducts to the
  ureter of each kidney
• The ureters carry the urine, which is normally
  free of microbes, to the urinary bladder, where
  it is stored until released through the urethra
  during micturition (urination)

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Flow of Urine Out of a System
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Urinalysis can reveal pH or water concentration
imbalances, the presence of glucose or proteins
and other conditions associated with infections,
metabolic disorders, and other diseases
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The Female Reproductive System

• The female reproductive system consists of the
  ovaries, uterine tubes, uterus, vagina, and
  external genitalia
• The paired ovaries contain cellular aggregations
  called ovarian follicles, each containing an ovum
  (plural ova), or egg, and surrounding epithelial
  tissue.
• During a womans reproductive years, an ovum
  capable of being fertilized is released once each
  month.
• The uterine tubes receive ova and convey them to
  the uterus.
• Fertilization usually occurs in the uterine
  tubes.
• The uterus is a pear-shaped organ in which a
  fertilized ovum develops.

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• It is lined with a mucous membrane called the
  endometrium, the outer portion of which is
  sloughed during menstruation.
• The vagina, also lined with mucous membrane,
  extends from the cervix (an opening at the
  narrow, lower portion of the uterus) to the
  outside of the body.
• It allows passage of menstrual flow, receives
  sperm during intercourse, and forms part of the
  birth canal.

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• The female external genitalia include the
  sexually sensitive clitoris, two pairs of labia
  (skin folds), and the mucous-secreting Bartholin
  glands.
• Because they nourish offspring, mammary glands
  (breasts) are considered part of the female
  reproductive system.
• These modified sweat glands develop at puberty
  and contain gland cells, embedded in fat, that
  produce milk and ducts that carry the milk to the
  nipple.

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Female Reproductive System
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The Male Reproductive System

• The male reproductive system consists of the
  testes, ducts, specific glands, and the penis
• The testes secrete the hormone testosterone into
  the bloodstream and produce sperm, which are
  conveyed through a series of ducts to the urethra
• Secretions from seminal vesicles, bulbourethral
  glands and the prostate gland mix with sperm to
  form semen

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Male Reproductive System
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Bacterial Urogenital Diseases

• Urinary Tract Infections (UTIs) are among the
  most common infections
• 2nd to respiratory infections
• Major cause is failure to completely empty
  bladder retained urine serves as a reservoir
• May result from age, pregnancy, enlarged
  prostate, paralysis
• Females are more susceptible due to shorter
  urethra and close proximity to anus
• Escherichia coli - causative agent in 80
• About 50 of nosocomial infections are UTIs

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• Pyelonephritis inflammation of kidneys
• Urethritis inflammation of the urethra
• Cystitis inflammation of the bladder
• Dysuria pain and burning upon urination
• Manifestations
• L-UTIs dysuria, increased frequency, urgency,
  suprapubic pain, bacteriuria, and pyuria
• U-UTIs back pain, chills, and fever, in addition
  to L-UTI symptoms
• Diagnosed by microbes in urine
• Treated with antibiotics
• Amoxicillin, quinolones, sulfa drugs

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Glomerulonephritis Brights Disease

• Autoimmune condition following strep throat
  caused by strains of S. pyogenes have cell wall
  components similar to glomerular tissues
• Antibiodies cant distinguish between pathogen
  and kidney tissues so they build up and damage
  the glomeruli resulting in an inflammatory
  response
• Blood and proteins leak into urine, May cause
  permanent kidney damage but most people recover
  in 3-12 months

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Leptospirosis

• Caused by the spirochete Leptospira interrogans
  a zoonosis usually acquired by humans through
  contact with contaminated urine, directly or in
  water or soil
• An infectious disease that affects the liver and
  kidneys in humans and some animals
• The bacteria live within the convoluted tubules
  of the kidney and shed into the urine
• In some parts of the world, more than 50 of the
  rats are carriers of Leptospira

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• Diagnosed by direct microscopic examination
• Responds to almost any antibiotic but only for
  the 1st 3 days
• Weils syndrome is an especially virulent form of
  the disease resulting in significant liver damage
• May be prevented by pet vaccines and avoiding
  contaminated water

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A colorized TEM of Leptospira interrogans
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Bacterial Vaginitis

• Vaginitis usually is caused by opportunistic
  organisms that multiply when the normal vaginal
  microflora are disturbed by antibiotics or other
  factors
• Several organisms account for a share each of
  vaginitis cases or at least serve as a marker for
  disruption of the vaginal flora.
• The bacterium Gardnerella vaginalis, in
  combination with anaerobic bacteria, accounts for
  about one-third of the cases

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• When pH is high (5-6) G. Vaginalis reacts with
  anaerobes causing disease
• Diagnosis is made from wet mounts of discharge
  that display clue cellsand absence of
  lactobacilli
• Treatment with metronidazole (Flagyl) suppresses
  anaerobes but allows lactobacilli to repopulate
• Tetracycline and ampicillin are alternative
  treatments
• Live-culture yogurt douche will replace
  Lactobacilli

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Normal Vaginal Epithelial Cells
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• A clue cell of Gardnerella infection in a
  vaginal smear
• Thick layer of bacteria can be seen clinging to
  the surface of the clue cell

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Other Causes of Vaginitis

• Trichomonas vaginalis
• opportunistic protozoan usually transmitted
  sexually
• Treated with metronidazole (Flagyl)
• Candida yeast
• characterized by scanty, thick, curd-like
  discharge
• Treated with Nystatin or Imidazole
• Main ingredients in over the counter treatments

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Toxic shock syndrome (TSS)

• Caused by strains of Staphylococcus aureus
  capable of producing exotoxin C
• Associated with the use of tampons especially
  when they are not replaced often
• Males with boils or other staph infections are
  susceptible
• Clinical manifestations include fever, drop in
  blood pressure, and rash
• Mortality rate2-5
• Less than 30 US cases reported each year
• Recurrence is a frequent possibility
• May treat prophylactically with antibiotics

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Parasitic Urogenital Diseases

• Transmitted primarily by sexual intercourse
• May also be transmitted through contaminated
  toilet seats and linens (usually in children)
• At least three species of protozoa of the genus
  Trichomonas can parasitize humans, but only T.
  vaginalis causes trichomoniasis

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Trichomonas vaginalis

• T. vaginalis is a large flagellate with four
  anterior flagella and an undulating membrane
• Infects urogenital tract surfaces in both genders
  and feeds on bacterial and cell secretions
• 5.5 to 6.0 is optimum pH for the organism
• Symptoms include intense itching and a copious
  white discharge, the consistency of raw egg white

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Trichomoniasis

• Diagnosis of trichomoniasis is by microscopic
  examination of vaginal or urethral smears and
  treatment includes application of metronidazole
  (Flagyl), which restores normal vaginal pH in
  women
• Flagyl cannot be used during pregnancy because it
  causes abortions, but it is important to
  eliminate the infection before delivery to
  prevent infecting the infant
• A vinegar douche usually is effective

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Trichomonas vaginalis (534X)
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Bacterial Sexually Transmitted Diseases--Gonorrhea

• Gram-negative, spherical or oval diplococcus with
  flattened adjacent sides resembles a pair of
  coffee beans facing each other
• Virulence factors
• Attachment pili- attach to cells of urinary tract
  and to sperm
• Endotoxin damages fallopian tubes
• Extracellular protease destroys IgA antibodies
• Capsule which allows evasion of phagocytosis

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G-, spherical or oval diplococci
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Symptoms of Gonorrhea--Urethral Drip of Pus in Men
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Symptoms of GonorrheaGonococcally Caused
Arthritis
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• May remain asymptomatic but carriers for up to 15
  years
• Diagnosed by inspecting genitals and culturing
  discharge
• Treatment
• Sulfa drugs, penicillin, doxycycline (also kills
  Chlamydia)
• No vaccine available