Bacterial Vaginosis (Gardnerella)
Jill C. Cash and Rhonda Arthur
Definition
A.Bacterial vaginosis (BV) is an infection of the vagina caused by an alteration in the normal flora of the vagina, with an increase in anaerobes and gram-negative bacilli as well as a decrease in the Lactobacillus flora.
Incidence
A.According to the Centers for Disease Control and Prevention (CDC), BV is the most common vaginal infection in women of childbearing age and is common in pregnant women. It is not considered exclusively a sexually transmitted infection (STI).
Pathogenesis
A.The main etiologic agent in BV is an increase in anaerobes in the vagina. The reason this occurs is unknown. The normal lactobacilli of the vagina decrease, and vaginal pH is increased in BV. The organisms present in BV cause the level of vaginal amines to be high. These amines are volatilized when the pH is increased, causing the characteristic fishy
odor.
B.Bacterial vaginitis is primarily polymicrobial, and the pathogens seen include Bacteroides species, Peptostreptococcus species, Eubacterium species, Mobiluncus species, Gardnerella, and Mycoplasma hominis. The incubation period is unknown.
Predisposing Factors
A.History of STIs.
B.Multiple sexual partners.
C.Intrauterine device (IUD) use.
D.Factors that change the normal vaginal flora:
1.Hormonal changes (menses, pregnancy).
2.Medications: Oral contraceptive use and antibiotic therapy.
3.Foreign bodies in the vagina (tampons, IUDs), semen, and douching.
Common Complaints
A.Vaginal discharge (thin, white, gray, or milky).
B.Fishy vaginal odor.
C.Postcoital odor.
Other Signs and Symptoms
A.Asymptomatic.
B.Increase in odor after menses.
C.Itching and burning, occasional.
Subjective Data
A.Elicit onset, duration, and course of presenting symptoms.
B.Review any changes in the characteristics and color of vaginal discharge. Does the patient’s partner(s) have any symptoms?
C.Review any symptoms of pruritus, perineal excoriation, burning; signs of urinary tract infection (UTI).
D.Review medication and medical history.
E.Determine if the patient is pregnant; note date of last menstrual period (LMP).
F.Question the patient for a history of STIs or other vaginal infections.
G.Review previous infection, treatment, compliance with treatment, and results.
H.Note last intercourse date.
I.Elicit information about possible foreign body.
J.Review use of vaginal deodorants or sprays, scented toilet paper, tampons, pads, and douching habits.
K.Review change in laundry detergent, soaps, and fabric softeners.
L.Review use of tight restrictive clothing, tight jeans, and nylon panties.
M.Review history for seizures and anticoagulant therapy.
Physical Examination
A.Check temperature, if indicated, blood pressure, pulse, and respirations.
B.Inspect: Examine external vulva and introitus for discharge, irritation, fissures, lesions, rashes, and condyloma.
C.Palpate:
1.Palpate the abdomen for masses or tenderness. Note enlarged or tender inguinal lymph nodes.
2.Palpate the external perineal area for vulvar masses.
3.Milk
the urethra for discharge.
4.Check for costovertebral angle (CVA) tenderness.
D.Pelvic examination:
1.Inspect:
a.Note the color, amount, and odor of discharge.
b.Inspect the cervix:
i.BV is a vaginosis rather than vaginitis. There is usually little or no inflammation of the vaginal epithelium associated with BV.
ii.BV is associated with a pink, healthy cervix; strawberry cervix
is seen with cervicitis due to Trichomonas vaginalis (TV).
iii.A red, edematous, friable cervix is seen with Chlamydia trachomatis (CT).
2.Speculum examination:
a.Inspect side walls for adhering discharge.
b.The clinical diagnosis of BV requires the presence of three of the following four signs:
i.Homogeneous, white, adherent vaginal discharge.
ii.Vaginal fluid pH greater than 4.5. Take smear for testing from the lateral walls of the vagina, not from the cervix, for accurate pH.
iii.A fishy, amine-like odor from vaginal fluid before or after mixing it with 10% potassium hydroxide (positive whiff test). Semen releases the vaginal amines; therefore, there is an increase in odor after intercourse.
iv.Presence of clue cells
(squamous vaginal epithelial cells covered with bacteria, causing a stippled or granular appearance and ragged, moth-eaten
borders) or coccobacilli forms, both in the fluid and adhering to the epithelial cells.
3.Bimanual examination: Check for cervical motion tenderness (CMT) and adnexal masses. BV may be a risk factor for pelvic inflammatory disease (PID).
Diagnostic Tests
A.Vaginal pH: Greater than 4.5 with BV; normal vaginal pH range is 4 to 4.5.
B.Wet prep with 10% potassium hydroxide and normal saline prep; microscopic examination of vaginal secretions should always be done. See Section II: Procedure for Wet Mount/Cervical Cultures.
C.Rapid chromogenic test to detect sialidase enzyme producing flora is a rapid reliable test that aids in diagnosis in absence of microscopy.
D.Herpes culture, if indicated.
E.Urinalysis and culture, if indicated.
Differential Diagnoses
A.BV.
B.Vulvovaginal candidiasis.
C.Trichomoniasis.
D.Gonorrhea (GC).
E.CT.
F.Presence of foreign body.
G.Normal physiologic discharge.
Plan
A.General interventions: Inform the patient regarding other modalities for treating BV. These methods include the following:
1.Vinegar and water douches: One tablespoon of white vinegar in 1 pint of water. Douche one to two times a week.
2.Lactobacillus and Acidophilus culture four to six tablets orally daily.
3.Garlic suppositories: One peeled clove of garlic wrapped in a cloth dipped in olive oil inserted vaginally overnight and changed daily.
B. 
See Section III: Patient Teaching Guide Bacterial Vaginosis.
BV is not considered an STI.
C.Pharmaceutical therapy:
1.Drug of choice:
a.Metronidazole (Flagyl) 500 mg orally twice daily for 7 days; or
b.Metronidazole gel 0.75% one applicator (5 g) per vagina at bedtime for 5 days:
i.Metronidazole is less expensive, easier to use, and associated with greater compliance.
ii.Side effects of metronidazole include sharp, unpleasant metallic taste in the mouth; furry tongue; central nervous system (CNS) reactions, including seizures; and urinary tract disturbances. Advise patients to avoid alcohol while taking metronidazole and 24 hours after completing the medication, or they will experience the severe side effects of abdominal distress, nausea, vomiting, and headache.
iii.Metronidazole may prolong prothrombin time in patients taking oral anticoagulants.
2.Other medications if the patient is unable to use oral metronidazole:
a.Clindamycin 300 mg orally twice daily for 7 days.
b.Metronidazole gel (MetroGel) 0.75% one applicator vaginally twice daily for 5 days.
c.Clindamycin 2% cream one applicator vaginally at bedtime for 7 days. Clindamycin cream is oil-based and may weaken latex condoms for at least 72 hours after terminating therapy.
3.Special considerations: Pregnancy: BV has been associated with adverse pregnancy outcomes; therefore, all symptomatic pregnant women and asymptomatic highrisk for preterm-delivery women require treatment:
a.Metronidazole 500 mg orally twice a day for 7 days or 0.75% metronidazole gel 5 g per vagina once daily for 5 days.
b.Clindamycin 300 mg orally twice a day for 7 days.
Follow-Up
A.Nonpregnant women: No follow-up is recommended unless indicated. Recurrence is common.
B.High risk for preterm delivery; pregnant women should be reevaluated 1 month after treatment.
C.Recommendations for treatment of BV in females infected with HIV are the same as for noninfected patients.
D.Consider treatment of the patient’s partner(s) in women with recurrent disease.
Consultation/Referral
A.Refer the patient to a physician for recurrence that is unresponsive to therapies.
Individual Considerations
A.Pregnancy: Clindamycin cream may be associated with increased adverse events in newborns and should not be used during the second half of pregnancy.
B.Partners: Routine treatment of a patient’s partner(s) is not recommended at this time because it does not influence relapse or recurrence rates.