Ch. 24 - Microbial Diseases of the Urinary and Reproductive Systems

Chlamydial Infections

- 85% of women are usually asymptomatic - 75% of males have inflammation, painful urination, purulent discharge from penis - Lymphogranuloma venereum, a severe form of chlamydia, causes a genital lesion and bubo in the groin - Caused by Chlamydia trachomatis (G-) --> Developmental cycle: unable to synthesize ATP ----> Elementary bodies are the dormant, infective form. Resistant to environmental extremes ----> Reticulate bodies are the obligate intracellular reproductive form - Enter body through scrapes or cuts - Infect conjunctival cells or cells lining mucous membranes - Destruction of infected cells and inflammation - Reinfection in the same site with the same or similar strain causes a hypersensitive immune response which can cause blindness, sterility, or sexual dysfunction - Most common reportable STD in the U.S. - Detection of chlamydial DNA by PCR is diagnostic - Treated with doxycycline or erythromycin - Prevented by abstinence or mutual monogamy

Sexually Transmitted Infections (STIs) and Diseases (STDs)

- Diseases caused by STIs are called STDs - STDs are a common worldwide occurrence - Young people who experiment with sex are at risk - Presence of lesions from STDs is a risk factor for transmission of HIV - Female adolescents are at risk because the cervical lining is prone to bacterial infection --> 15 year old girl 12.5% chance of PID, 25 year old 1.25% - Prevention includes abstinence or mutual monogamy - Condoms must be used properly and consistently to provide protection, failure rate of 17-25%

Trichomoniasis

- Females have vaginal discharge and vaginal irritation - Males are typically asymptomatic - Caused by Trichomonas vaginalis --> flagellated protozoan parasites of animals and humans --> 5 anterior flagella and an undulating membrane --> reproduces at pH 5 to pH 6. Normal lactobacilli keep the pH of the vagina at 4.0 to 4.5; thus, the vaginal microbiome helps keep Trichomonas in check - Only lives in humans: vagina, urethra, prostate - Binds to epithelial cells and causes inflammation - Transmission primarily via sexual intercourse, cannot live long outside the body - Increases risk of infection by HIV and other STDs - Diagnose by presence of Trichomonas in clinical samples - Treat with a single dose of oral metronidazole or tinidazole - Prevent by avoiding sexual intercourse with infected persons

Bacterial Urinary Tract Infections

- Frequent, urgent, painful urination (dysuria) - Urine may be cloudy with foul odor - Enteric bacteria are the most common cause - Escherichia coli causes most cases - Virulence factors include flagella and attachment fimbriae - Often self-inoculate fecal bacteria into the urethra - More common in females - Diagnosis based on urinalysis - Many cases resolve without treatment - Some require treatment with antimicrobial drugs - Prevent by limiting contamination by fecal microbes

Gonorrhea ("The Clap" from clapoir)

- Men experience painful urination and a purulent discharge (pus) - Women are often asymptomatic (50-80%) --> Pelvic inflammatory disease develops in 25% - Caused by Neisseria gonorrhoeae --> G- diplococci - Virulence factors: fimbriae, capsule, and cell wall antigen lipooligosaccharide (contains lipid A) - The cocci also protect themselves from the immune system by secreting a protease enzyme that breaks down secretory IgA in mucus - Survives phagocytosis and spreads via neutrophils - Bacteria attach to epithelial cells of the mucous membranes. - Causes inflammation, damage, infertility, and death - Gonorrhea occurs only in humans - Risk increases with frequency of sexual encounters - Morphological detection in pus or use of genetic probes to diagnose asymptomatic infection - Dual therapy: ceftriaxone and azithromycin --> Resistant to penicillin, tetracycline, erythromycin, and more.

Normal microbiota of the female reproductive system

- Only the vagina is colonized by various microorganisms, depends on hormone levels - Candida (fungus)

Genital Warts

- Papillomas (warts) on the genitalia and surrounding areas --> Large growths called condylomata acuminata may form, appear as "cauliflower" shaped - May also form on the face, trunk, hands, feet, elbows, or knees. - Caused by human papillomaviruses (HPV) (dsDNA) - HPV can cause various cancers - Common strains that cause cervical cancer - HPV 6 & 11 cause 90% of genital warts - HPV 16 & 18 cause 70% of all cervical cancer - HPVs invade skin or mucous membranes during sex - Primary concern is due to an increased risk of cervical cancer - Most common STD in the U.S. (90%) - Diagnosis made by presence of warts - Variety of methods available to remove warts - Vaccine, Gardasil, available against HPV strain associated with cervical cancer and warts --> Vaccine targets: HPV 6, 11, 16, 18

Normal microbiota of the male reproductive system

- Regions above the prostate are sterile

Vaginal Candidiasis

- Severe vaginal itching and burning intensified by urination - Growth of white mucoid colonies - Most commonly caused by Candida albicans - Normal microbiota of skin and mucous membranes - Candida overgrows if vaginal pH becomes alkaline or normal microbial populations are reduced --> Can become systemic in the immunocompromised - Can be passed person-to-person via birth or sexual intercourse - Identification of Candida in presence of symptoms is diagnostic - Treated with topical azole cream or oral fluconazole - Avoiding excessive use of antibacterial drugs can prevent candidiasis

Genital Herpes

- Small blisters on or around the genitals or rectum - Human herpesvirus 2 (HHV-2) causes most cases, but can be caused by HHV-1 --> HHV are dsDNA viruses - Virus can become latent as circular DNA in nerve cells - Herpesvirus kills epithelial cells at infection site - Blisters may form at sites far from initial infection site, rupture and release millions of HHV. Turn into a painful lesion ulcer - Genital herpes quadruples the risk of HIV infection - Infants may be infected during birth - 15% of US have HHV-1, 40% have HHV-2 - Diagnosis made based on characteristic lesions - Administration of acyclovir or other antiviral agents can lessen symptoms - Condoms often provide little protection - Prevent through abstinence or mutual monogamy - Infected pregnant women should deliver by C-section

Staphylococcal Toxic Shock Syndrome

- Sudden-onset fever, chills, vomiting, diarrhea, low blood pressure, confusion, and severe red rash - Individuals go into shock if untreated - Caused by some strains of S. aureus - S. aureus grows exceedingly well on super-absorbent tampons, especially when a blood-soaked tampon remained in place for a prolonged period - These strains produce exotoxins called toxic shock syndrome toxins (TSST), a superantigen --> exotoxins bind simultaneously to major histocompatibility complex II molecules on antigen-presenting cells and T cell receptors on T cells; however, they bind to sites other than the normal antigen-binding sites of these immune system molecules. --> When a toxin molecule binds two defensive cells together in this fashion, it activates the T cell --> As a result of the action of many such toxin molecules, many more T cells are activated than in a cellular immune response. --> These activated T cells release an overabundance of cytokines that trigger the manifestations of TSS - 75% of cases are due to TSST-1 - Absorption of toxin into blood triggers toxic shock syndrome. Causes low blood pressure, coma, and death. - Most cases occur in menstruating females - Diagnosis based on signs and symptoms - Considered medical emergency - Requires removal of foreign material and antimicrobial drugs - Avoiding tampons or using less absorbent tampons reduces risk

Syphilis

- Treponema pallidum causes syphilis --> G- spirochete --> Only lives in humans; heat, disinfectants, soaps, drying, atmospheric oxygen destroy it --> Too narrow to see with light microscope - Major virulence factors have been difficult to identify --> Virulent strains have a glycocalyx and hyaluronidase - Transmitted mostly via sexual contact - Sometimes transmitted from mother to child - 66% of individuals do not develop tertiary syphilis - Syphilis occurs worldwide - Diagnose primary, secondary, and congenital syphilis with antibody test or dark-field microscopy - Tertiary syphilis is difficult to diagnose, not an active infection - Penicillin G used to treat all but tertiary syphilis - No proven alternative treatment for those allergic to penicillin - All sexual partners of syphilis patients must be treated with prophylactic penicillin G

Normal Microbiota of the Urinary System

- Urethra supports colonization by some microorganisms --> Microorganisms in the urethra can move up to infect the kidneys - Remainder of the urinary organs are sterile --> because of the normally acidic pH of urine and the flushing action of urination - Bacteroides, Lactobacillus, Staphylococcus, Streptococcus, Mycobacterium - Opportunistic and sexually transmitted microbes can infect the reproductive system

Leptospirosis

- Zoonotic disease primarily seen in animals - Abrupt fever, rash, myalgia, muscle stiffness, and headache - Jaundice may develop in severe infection - Rarely fatal but due to kidney and liver failure, meningitis, or respiratory distress - Caused by Leptospira interrogans --> G- spirochete - Grows asymptomatically in many wild and domestic animals - Transmitted by contact with urine of infected animal or urine-contaminated water - Results in bacteremia, often concentrating in the kidney and liver causing severe or fatal damage. - Rare in the U.S. - Tropics/subtropics or in poor living conditions - Diagnosis based on antibody test - Treat with antimicrobial drugs --> Intravenous penicillin G treats severe infections; oral doxycycline, ampicillin, or amoxicillin are drugs of choice for less severe cases - Prevent by avoiding contaminated water

Bacterial Vaginosis

- noninflammatory infection of the vagina --> "vaginosis" rather than "vaginitis" - homogenous white vaginal discharge with a "fishy" odor - some itching/irritation at vaginal opening - esults when the normal lactobacilli of the vagina are replaced with a large number of facultatively or obligate anaerobic bacteria such as Gram-positive Gardnerella vaginalis and Mycoplasma hominis - a decline in the number of lactobacilli populating the vagina results in a pH in the vagina higher than the normal 4.5 --> This either promotes or allows the growth of the bacteria associated with bacterial vaginosis - associated with having multiple sexual partners and vaginal douching - diagnose bacterial vaginosis by its signs, including odor, discharge characteristics, and vaginal pH greater than 4.5 - The presence of so-called clue cells, which are vaginal epithelial cells completely covered with bacteria, supports the diagnosis - treatment with oral or vaginal metronidazole or clindamycin - no absolute preventive measures, but sexual abstinence and refraining from douching are beneficial

glomerulonephritis

- the body does not remove from circulation antibodies bound to the antigens of some strains of group A Streptococcus (GAS) - antibody-antigen complexes accumulate in the glomeruli of the kidneys, triggering inflammation of the glomeruli and nephrons - obstructs blood flow through the kidneys and leads to hypertension (high blood pressure) and low urine output. - The patient's urine often contains blood and proteins. - Young patients usually recover fully from glomerulonephritis, but progressive and irreversible kidney damage may occur in adults

Life Cycle of Chlamydia

1. Elementary body (EB) attaches to receptor on host cell (0 hrs) 2. EB triggers its own endocytosis by host cell 3. EB converts body (RB) within vesicle (10 hrs) 4. RB divides rapidly resulting in multiple RBs. The vesicle is now called an inclusion body. 5. Most RBs convert back into EBs (21 hrs) 6. EBS are released from host cell (40 hrs) 1. cycle repeats

Review - Which microbe is the most common cause of urinary tract infections? A. Escherichia coli. B. Pseudomonas aeruginosa. C. Staphylococcus aureus. D. Mycoplasma hominis

A

Review - Which gonorrhea patients most often lack obvious symptoms? A. Women. B. Immunocompromised people. C. Men. D. The elderly.

A - Among women who are infected, 50-80% lack signs or symptoms of gonorrhea.

Review - Which type of antibody produced by a mother can protect her unborn baby? A. IgG. B. IgM. C. IgA. D. IgD.

A - IgG antibodies are the only antibodies that can traverse the placenta to protect an unborn baby. Among the five classes of antibodies, IgG antibodies are the only ones that can traverse the placenta to protect a fetus.

Review - If a person has had gonorrhea, what is the best way to prevent the disease from recurring? A. Oral contraceptives. B. Abstinence, monogamy, or use of condoms. C. Prophylactic (preventive) drugs. D. Immunization.

B - Contracting gonorrhea does not confer long-term specific immunity, so patients can be reinfected; abstinence, monogamy, or use of condoms reduce the likelihood of reinfection.

Review - What is the best way to prevent cervical cancer? A. Safe sex. B. Immunization. C. Oral contraceptives. D. Proper genital hygiene.

B - Immunization is the best way to prevent cervical cancer, which is caused by human papillomaviruses

Review - What is the term used for microbiota that normally do not cause disease but that might cause disease when the balance of microbiota is disrupted by use of antimicrobial drugs? A. Transient pathogens. B. Opportunistic pathogens. C. True pathogens. D. Commensal pathogens.

B - Opportunistic pathogens do not normally cause disease but can do so when the balance of microbiota is disrupted. Opportunistic pathogens do not normally cause disease but can do so when a patient is immune compromised or when the balance of normal microbiota is disrupted. The microbes may be commensal, mutualistic, or transient; however, if they cause disease, they are referred to as opportunistic pathogens.

Review - What disease is caused by Gardnerella vaginalis? A. Urethritis. B. Toxic shock syndrome. C. Vaginosis. D. Vaginal yeast infections.

C

Review - Which of the following is the most common sexually transmitted pathogen in the United States? A. Human herpesvirus 2. B. Treponema pallidum. C. Human papillomavirus. D. Neisseria gonorrhoeae..

C

Review - Which life stage of Chlamydia trachomatis attaches to host cells and infects them? A. An inclusion body. B. A reticulate body. C. An elementary body. D. An initial body

C - An elementary body attaches to a receptor on the host cell.

Review - Why are special stains or phase contrast microscopy necessary to observe Treponema pallidum? A. T. pallidum does not take up crystal violet or safranin. B. T. pallidum is a mycoplasma and thus too small to be seen with a regular light microscope. C. T. pallidum is too thin to be visible with regular light microscopy. D. T. pallidum is an acid-fast staining bacterium.

C - At 0.1 μm in diameter, T. pallidum is too thin to be viewed with a regular light microscope

Review - At what stage of the disease are syphilis patients most contagious? A. The latent phase. B. The secondary phase. C. The primary phase. D. The tertiary phase.

C - In the early stages of the disease, the spirochetes are more numerous, so patients are most contagious.

Review - How do herpesviruses enter a host cell? A. By direct injection of the capsid and its contents. B. The virus does not enter; it injects only its DNA into a host cell. C. By fusion of their viral envelope with the host cytoplasmic membrane. D. Through endocytosis.

C - The envelope of human herpesvirus fuses with the cytoplasmic membrane to introduce the capsid into the host cell.

Review - Why is Leptospira interrogans highly motile? A. It has a tuft of flagella. B. It has cilia. C. It has two axial filaments. D. It has peritrichous flagella.

C - The spirochete L. interrogans is highly motile because of its two axial filaments, one at each end.

Review - Which sexually transmitted pathogen is a protozoan? A. Candida albicans. B. Neisseria gonorrhoeae. C. Trichomonas vaginalis. D. Treponema pallidum.

C - Trichomonas vaginalis is a parabasalid protozoan.

Disease at a Glance - Pelvic Inflammatory Disease (PID)

Cause -- Chlamydia trachomatis (Gram-negative obligate intracellular bacterium); Neisseria gonorrhoeae (Gram-negative diplococcus bacterium); or Gardnerella vaginalis (Gram-positive coccobacillus bacterium) in rare instances. In 30-40% of cases, PID is caused by infection with multiple bacteria simultaneously. Virulence factors -- Chlamydia—small size, intracellular lifestyle; Neisseria—capsule, fimbriae, lipid A; Gardnerella—ability to inhibit movement of neutrophils, adhesins, formation of biofilm. Portal of entry -- Mucous membrane of vagina, sexual transmission, and then migration ascending into the uterus or uterine tubes. Signs and symptoms -- Inflammation, fever, abdominal pain. Left untreated, PID can lead to ectopic pregnancies and sterility. Incubation period -- Months to years after initial infection. Susceptibility -- Women with untreated gonorrhea or chlamydial infections, especially those under age 20. Treatment -- Antimicrobial drugs such as ofloxacin, metronidazole, doxycycline, and/or ceftriaxone. Prevention -- Abstinence or mutual monogamy with an uninfected partner; early treatment of all STDs. Condoms provide some protection from Neisseria infection.

Disease at a Glance - Toxic Shock Syndrome

Cause -- Exotoxin-producing strains of Staphylococcus aureus (Gram-positive coccus). Virulence factors -- Exotoxins, enterotoxins. Portal of entry -- Staphylococcus either grows in the vagina or enters the body through a wound, grows, and produces toxin that enters the bloodstream. Signs and symptoms -- Sudden onset of high fever, vomiting, rash, extremely low blood pressure, and sore throat. Incubation period -- Two to three days. Susceptibility -- Menstruating women who use highly absorbent tampons for extended periods, newly delivered mothers, and surgery patients are at higher risk. Treatment -- Supportive therapy is extremely important; administration of vancomycin and antistaphylococcal immunoglobulin. Prevention -- Avoid vaginal insertions such as highly absorbent tampons, vaginal sponges, or diaphragms, or use them intermittently and for shorter periods.

Disease at a Glance - Gonorrhea

Cause -- Neisseria gonorrhoeae (Gram-negative diplococcus). Virulence factors -- Capsule, fimbriae, lipooligosaccharide (lipid A, sugar), highly variable surface antigens among strains. Portal of entry -- Mucous membranes of genitalia; sexual transmission. Signs and symptoms -- Men generally experience painful urination and pus-filled discharge. Women are generally asymptomatic. Incubation period -- Two to five days. Treatment -- Simultaneous ceftriaxone and azithromycin. Prevention -- Effective: Sexual abstinence, mutual monogamy. Somewhat effective: Proper, consistent use of condoms.

Disease at a Glance - Syphilis

Cause -- Treponema pallidum (spirochete). Virulence factors -- Glycocalyx, adhesins, hyaluronidase. Portal of entry -- Mucous membranes of genitalia; sexual or congenital transmission. Signs and symptoms -- Primary syphilis: hard, nonpainful genital chancre that disappears after three to six weeks. Secondary syphilis: sore throat, headache, mild fever, malaise, myalgia, and rash that lasts several weeks or months. Latent syphilis: generally asymptomatic; lasts for decades. Tertiary syphilis: dementia, blindness, paralysis, and gumma lesions. Incubation period -- 10-90 days (average 21 days) for the primary form of the disease. Susceptibility -- Sexually active individuals and fetuses whose mothers are infected. Treatment -- Penicillin. Prevention -- Sexual abstinence, mutual monogamy, or use of condoms.

Disease at a Glance - Trichomoniasis

Cause Trichomonas vaginalis, a single-celled, flagellated protozoan in the taxon Parabasala. Virulence factors Adhesins, proteolytic enzymes, hemolysis, cell-detaching factor. Portal of entry Mucous membrane of genital tracts. Signs and symptoms In females: malodorous, yellow-green vaginal discharge, vaginal irritation, possibly spot bleeding, dysuria; in males: usually asymptomatic, though the disease may cause urethritis and prostatitis. Incubation period 4-28 days. Susceptibility Sexually active individuals, more commonly heterosexual than homosexual; uncircumcised males may be more at risk than are circumcised males; in pregnant women, trichomoniasis can result in low birth weight and premature birth of baby. Treatment Metronidazole or tinidazole. Prevention Abstinence, mutual monogamy of both partners, consistent and accurate condom usage

What is the most common sexually transmitted bacterium?

Chlamydia trachomatis

Review - What is cystitis? A. Inflammation of the prostate. B. Inflammation of the kidneys. C. Inflammation of the urethra. D. Inflammation of the bladder.

D

Review - Which phase of syphilis presents with a rash, which may be on the palms of the hands and the soles of the feet? A. The latent phase. B. The primary phase. C. The tertiary phase. D. The secondary phase.

D

Review - Which sexually transmitted pathogen causes lymphogranuloma venereum? A. Candida albicans. B. Treponema pallidum. C. Neisseria gonorrhoeae. D. Chlamydia trachomatis.

D

Review - Why do scientists use an antibody test to reveal the presence of Leptospira interrogans in a sample? A. It is hard to see the pink-colored L. interrogans bacteria in a blood sample. B. L. interrogans is too small to be visible with a light microscope. C. L. interrogans is secreted only in very small numbers. D. L. interrogans does not stain well with the Gram stain

D

Review - What structure do spirochetes use for motility? A. Peritrichous flagella. B. Fimbriae. C. Cilia. D. Axial filament.

D - Spirochetes use their axial filaments for motility. Spirochetes (flexible, spiral-shaped bacteria) have axial filaments, which are bundles of flagella that wrap around the bacterium between its cell wall and its outer membrane. This allows the bacteria to move in a corkscrew-like fashion.

4 Phases of Syphilis

Primary syphilis - Small chancre (sore) at site of infection --> A small, painless, reddened, hard lesion called a chancre forms at the site of infection 10-21 days following exposure. Although chancres typically form on the external genitalia, about 20% form in the mouth, around the anus, or on the fingers, lips, or nipples. Chancres are often unobserved, especially in women, in whom these lesions frequently form on the cervix. Chancres last three to six weeks Secondary syphilis - Sore throat, headache, fever, lymphadenopathy (diseased lymph nodes), malaise, rash (does not itch or hurt, but persists for months) Latent syphilis - No symptoms, may last 10+ years Tertiary syphilis - May take 3-15 years. Dementia, blindness, paralysis, heart failure, or gummas. Result of years of untreated infection. --> syphilitic gummas are rubbery, swollen lesions that can occur in bones, in nervous tissue, or on the skin --> rarely develop in patients in countries where antimicrobial drugs are available