SEXUALLY TRANSMITTED INFECTIONS (STI) IV

General Goal: To know the major cause(s) of these infections, how they are transmitted, and the major manifestations of the infections.

Specific Educational Objectives: The student should be able to:

1. Identify the common cause of vaginitis discussed in this handout. Know the common or pathognomonic signs of the diseases.

2. Describe the major manifestations of each infection and differentiate it from other infections in the course.

3. Describe how you diagnose, treat and prevent these infections.

Reading: MEDICAL MICROBIOLOGY by P.R. Murray, K.S. Rosenthal, G.S. Kobayashi and M.A. Pfaller, 3rd Edition. depends on the organism.

F.S. Southwick, Infectious Diseases in 30 Days, 1^st edition, McGraw Hill. p. 289-318.

Lecture: Dr. Neal R. Chamberlain

References: 

1. Burstein GR, Zenilman JM. Nongonococcal urethritis--a new paradigm. Clin Infect Dis 1999 Jan;28 Suppl 1:S66-73
2. Hoeprich, PD., MC. Jordan, and AR. Ronald. Infectious Diseases: A Treatise of Infectious Processes. 5th edition. 1994. J.B. Lippincott Company, Philadelphia, PA.
3. CDC. The national plan to eliminate syphilis from the United States. Atlanta, Georgia: US Department of Health and Human Services, CDC, National Center for HIV, STD, and TB Prevention, 1999:1--84.
4. Sexually Transmitted Disease Guidelines 2002. Recommendations and Reports
   May 10, 2002/Vol. 51/No.RR-6 (http://www.cdc.gov/std/treatment/TOC2002TG.htm)

Diseases characterized by vaginal discharge.

A recent Gallup survey found that very few women have a thorough understanding of vaginitis. While 95 percent of women surveyed had heard about yeast infections only 36 percent had ever heard of a more common vaginal infection called bacterial vaginosis (BV).

Bacterial Vaginosis (BV) due to Gardnerella vaginalis, Mycoplasma hominis and various anaerobic bacteria including Mobiluncus sp., and Prevotella sp.

BV is the most common vaginal infection. The disease has been found in 12 to 25 percent of women in routine clinic populations, 10 to 26 percent of women in obstetrics clinics and 32 to 64 percent of women in clinics for sexually transmitted diseases (STDs).

Other organisms can cause vaginitis. Candida albicans (Candidiasis) and Trichomonas vaginalis (Trichomoniasis). These infections of the vagina are discussed in this handout as well.

Vaginal infections are often accompanied by vaginitis, which is an inflammation of the vagina characterized by discharge, irritation, and/or itching. The cause of vaginitis cannot be adequately determined solely on the basis of symptoms or a physical examination. Laboratory tests allowing microscopic evaluation of vaginal fluid are required for a correct diagnosis. A variety of effective drugs are available for treating vaginal infections and accompanying vaginitis.

Bacterial Vaginosis

A. Etiology

Bacterial Vaginosis (BV) due to Gardnerella vaginalis, Mycoplasma hominis and various anaerobic bacteria including Mobiluncus sp., and Prevotella sp.

B. Epidemiology

Bacterial vaginosis (BV) is the most common cause of vaginitis symptoms among women of childbearing age. BV--previously called nonspecific vaginitis or Gardnerella-associated vaginitis-- can be transmitted through sexual activity, although the organisms responsible also have been found in young women who are not sexually active.

Bacterial vaginosis is caused by an overgrowth of bacteria rather than yeast or other organisms. These are primarily anaerobic bacteria (requiring no oxygen) and an organism called Gardnerella, all of which can be found in low numbers in the healthy vagina. In women with BV, the vaginal balance is disrupted so that these bacteria overgrow at the expense of protective bacteria known as lactobacilli. Lactobacilli excrete hydrogen peroxide to help maintain a healthy and normal balance of microorganisms in the vagina. Women who have been diagnosed with BV have been found to have up to 1,000 times more anaerobic bacteria than women without the disease. Instead of the normal predominance of Lactobacillus bacteria, increased numbers of organisms such as Gardnerella vaginalis, Bacteroides, Mobiluncus, and Mycoplasma hominis are found in the vagina in women with BV.

A few studies have also correlated BV with increased douching, an increased number of sexual partners and use of intrauterine devices. While sexual activity may increase the likelihood of developing BV, the condition has also been found in sexually inexperienced and monogamous women.

C. Manifestations

1. An unpleasant vaginal odor in varying degrees and an excessive white or gray vaginal discharge with a milk-like consistency. Women often report that the odor is particularly embarrassing after sexual intercourse. When semen mixes with vaginal secretions, it lowers the acidity level to make the odor particularly strong. Odor may also be more noticable around the time of menses.
2. Vaginal itching or burning are also sometimes present.
3. Up to 40 percent of women with BV may experience no outward symptoms
4. BV has been associated with pelvic inflammatory disease, which can result in infertility, as well as increased risk of endometritis, cervicitis, pregnancy complications, and post-operative infections. Pregnant women with BV in the 23rd to 26th weeks of pregnancy were 40 percent more likely to deliver a low birth-weight baby (less than 5.5 lbs).

Three of the four criteria should be positive
• thin homogeneous discharge.
• pH of discharge >4.5.
• Clue cells in saline wet mount or Gm stain of vaginal discharge.
• Mixture of vaginal discharge and 10% KOH liberates an "amine-like" or "fishy" odor.

antibiotic therapy: 

Metronidazole 500 mg orally twice a day for 7 days,
     OR
Metronidazole gel 0.75%, one full applicator (5 g) intravaginally, once a day for 5 days,
     OR
Clindamycin cream 2%, one full applicator (5 g) intravaginally at bedtime for 7 days..

BARBARA A. MAJERONI, M.D., 1998. Bacterial Vaginosis: An Update. American Family Physician. March 15, 1998. http://www.aafp.org/afp/980315ap/majeroni.html

Mycotic vulvovaginitis or vulvovaginal candidiasis

1. Epidemiology

Overgrowth with C. albicans is actually the second most common cause of vaginitis.

When the delicate balance of organisms in the vagina is upset, the yeast may overgrow and cause vaginitis. For example, when a woman takes certain antibiotics to treat a bacterial infection, the antibiotic may also kill the lactobacilli that produce hydrogen peroxide to protect against yeast overgrowth. Other factors that may upset the balance and lead to yeast infection include pregnancy, obesity, diabetes, birth control pills, steroids, prolonged exposure to moisture and poor feminine hygiene.

• A thick, curd like vaginal discharge (epithelial cells and masses of hyphae/pseudohypha)
• intense pruritus of the vulva
• erythematous vagina and labia

• evaluation of symptoms and clinical setting
• Gram stains of exudates (image 1 and 2)

Intravaginal Agents:

Butoconazole 2% cream 5 g intravaginally for 3 days,
     OR
Butoconazole 2% cream 5 g (Butaconazole1-sustained release), single intravaginal application,
     OR
Clotrimazole 1% cream 5 g intravaginally for 7--14 days,
     OR
Clotrimazole 100 mg vaginal tablet for 7 days,
     OR
Clotrimazole 100 mg vaginal tablet, two tablets for 3 days,
     OR
Clotrimazole 500 mg vaginal tablet, one tablet in a single application,
     OR
Miconazole 2% cream 5 g intravaginally for 7 days,
     OR
Miconazole 100 mg vaginal suppository, one suppository for 7 days,
     OR
Miconazole 200 mg vaginal suppository, one suppository for 3 days,
     OR
Nystatin 100,000-unit vaginal tablet, one tablet for 14 days,
     OR
Tioconazole 6.5% ointment 5 g intravaginally in a single application,
     OR
Terconazole 0.4% cream 5 g intravaginally for 7 days,
     OR
Terconazole 0.8% cream 5 g intravaginally for 3 days,
     OR
Terconazole 80 mg vaginal suppository, one suppository for 3 days.

Oral Agent:

Fluconazole 150 mg oral tablet, one tablet in single dose.

Trichomoniasis

A. Etiology

The etiological agent is a flagellated protozoan Trichomonas vaginalis.

1. Morphology
• It is a pear shaped organism exhibiting a characteristic motility described as a wobbling and rotating motion, recognition of this on wet mounts is important in diagnosis.

• T. vaginalis is a common parasite of both males and females and the incidence is in part related to hygiene.
• Intercourse is the usual method of transmission, especially via asymptomatic males.
• In rare instances it  may be passed on by wet towels, washcloths and bathing suits
• The infection often persists because the parasite rarely causes symptoms in men, so that reinfection of women by untreated men is common.
• Some women can be infected for months to years as the infection is passed back and forth between the woman and her sexual partner. For this reason, both sexual partners must be treated at the same time, even if they are in a monogamous relationship.

• Vaginitis and urethritis in females
• Disruption of normal flora organisms in vagina may alter pH (>4.5) and other factors which allow T. vaginalis to overgrow.
• Proliferation of the organisms is associated with a low grade inflammation manifested by:
• Itching and burning
• Painful urination
• A frothy, green, creamy discharge, that is described as being leukorrheic and very malodorous.
• Because of the ease of anatomic spread to the urethra, urethritis develops; again it is manifested chiefly by
• Dysuria
• Frequency and urgency
• many women with this infection may not have any symptoms
• Urethritis and prostatovesiculitis in males is usually asymptomatic but may be manifested by:
• Dysuria
• Urgency and frequency
• Occasionally in severe cases there is exudate formation

• Low grade inflammation is associated with the presence of high numbers of trichomonads.
• These high numbers of trichomonads become established because something has disrupted the normal flora and allowed them to overgrow.

• Clinical diagnosis depends upon recognition of the symptoms of dysuria, frothy, cream, malodorous discharges associated with punctate lesions and hyperemia of the vagina - highly suggestive.
• The most practical method of specific diagnosis is microscopic examination for motile trichomonads in vaginal or urethral discharges.

• Metronidazole 2 g orally in a single dose.