Lactobacilli & Bacterial Vaginosis

[Guest guest]

DeeTroll wrote: ====================================== Premenopausal women have a flora of mostly lactobacilli, and is important in conferring protection to the woman. As she ages and goes into menopause she tends to lose much of this protection with the loss of estrogen. (she also loses a lot of estrogen with breast feeding) If not enough lactobacilli in the vagina it predisposes a woman to bacterial vaginitis and often the fishy odor and usually will have a higher pH level which estrogen will normalize. Patients with BV have 'decreased' levels of normal hydrogen peroxide-producing Lactobacillus species in the vagina and 'high'

concentrations of anaerobic bacteria (including Prevotella and Mobiluncus species), Gardnerella vaginalis, and Mycoplasma hominis.5 Normally, the hydrogen peroxide­ producing lactobacilli help maintain a healthy acidic pH in the vagina of less than 4.5 and inhibit the growth of most other vaginal bacteria.7 In healthy patients, lactobacilli account for more than 95% of the bacteria found in the vagina. In contrast, women with BV (Bacterial vaginosis) *note* In some cases you'll see the word Bacterial ''vaginitis'', I believe some use that to differentiate the inflammatory and 'perhaps' an infectious stage from a symptomless one? ('itis' means inflammatory) but when really looking up the two words in depth, vaginosis or vaginitis.. they are most often

interchanged & both mean an infection.(could be yeast or bacterial) but with the B. (as in BV) in front it's a bacterial one. Dee~ have a 1,000-fold higher concentration of other bacteria--including those mentioned previously bacterias--in the vagina, in association with a remarkable 'absence' of lactobacilli.7 The cause of this change in vaginal flora is not understood. While BV is associated with having multiple sexual partners and frequent sexual activity, it is considered to be sexually associated rather than sexually transmitted. Women who never have had intercourse can have BV. However, women who have recently acquired a new partner or who have intercourse frequently are more prone to getting BV. In women who have sex with other women, BV occurs very frequently in both members if one partner has the infection.10 Under estrogen stimulation, the lower urogenital tract is healthy due to its acidic pH and high blood flow. The vagina and lower urinary tract arise from the same embryologic origin, the endoderm of the primitive urogenital sinus. Estrogen receptors are heavily concentrated in the vagina. They are also present in the urethra and to a lesser extent in the bladder trigone, pelvic floor muscles, and connective tissues [9]. The epithelial and subepithelial tissues of the vaginal mucosa are responsible for vaginal thickness, distensibility, and a defensive response to pathologic organisms. The ''estrogen-dominant'' environment enables the protective lactobacilli to convert glycogen to lactic acid, creating an acidic vaginal pH. At an acidic pH, the

coliform bacteria, such as Escherichia coli and yeast, have a hard time surviving. At a lower pH, the normal bacteria in the vagina, the lactobacilli, are able to destroy the over production of pathogenic bacteria. As estrogen levels decline, (the pH level becomes less acidic) the pathogenic bacteria overgrow, and vaginitis results. As the pelvic blood flow declines with age and the cellular glycogen content decreases, the vaginal pH becomes more basic (less acidic) and the tissues become pale, thin, have less rugations, and are less likely to combat the infectious organisms. The vagina is easily traumatized when physically manipulated, and has a greater tendency to bleed. Small ulcerations may form in the superficial epithelium, which, upon healing, create scar tissue. Vaginal adhesions may occur, making the vagina less distensible, resulting in painful intercourse, otherwise termed dyspareunia. In the worst-case scenario, the vaginal sidewalls may fuse together, obliterating the vagina and making an evaluation and/or intercourse impossible. (not likely in a premenopausal woman) DT. Diagnostic Guidelines The differential diagnosis of BV should include evaluation for two other common vaginal infections: (other than a lack of estrogen, dt) 1. trichomoniasis, which is caused by Trichomonas vaginalis, and 2.

candidiasis, which is caused by Candida albicans (Table). 3. Infection with Chlamydia trachomatis and Neisseria gonorrhoeae also should be considered. 4. Furthermore, contact dermatitis from spermicidal creams,(esp. non-oxynol 9) latex in condoms, or douching also may 'mimic' the symptoms of BV. According to Centers for Disease Control and Prevention (CDC) guidelines, diagnosis of BV may be made by clinical criteria or Gram's stain.5 Clinical criteria for bacterial vaginosis require that patients have at least three of the following four signs: 1. a homogeneous, whitish, noninflammatory discharge that smoothly coats the vaginal walls; 2. the presence of clue cells on microscopic examination; a vaginal pH of greater than 4.5; and 3. an amine or "fishy" odor before or after 10% potassium hydroxide (KOH) is applied to a sample of vaginal discharge. When evaluating a woman

with vaginal complaints, initial laboratory work should consist of measuring vaginal pH, as well as saline and 10% KOH microscopy. A swab touched to a strip of pH paper allows the examiner to determine whether BV may be present. A pH of less than 4.5 effectively rules out the presence of BV. (Because BV thrives in a higher pH level. Dee) Saline microscopy permits visualization of clue cells (Figure) and abnormal flora, that one usually sees with BV, and also serves as a test for trichomoniasis. By lysing the vaginal epithelial cells, 10% KOH allows for easier identification of fungal elements such as pseudohypha or blastospores. However, the absence of T vaginalis or Candida species on these slides does not eliminate the possibility of

infection with these organisms; if either of these organisms is suspected as a cause of symptoms, appropriate ancillary tests such as culture for yeast or T vaginalis, or alternatively, monoclonal antibody testing for T vaginalis will serve to clarify the diagnosis. Figure. Clue cells indicating bacterial vaginosis infection. © SPL/Photo Researchers, Inc. Gram's stain is another acceptable method for diagnosing BV. This test determines the relative concentration of the bacterial morphotypes commonly found in women with BV.

Although they are less commonly used, there are other tests that may be useful to diagnose BV: a DNA probe-based test for high concentrations of G vaginalis; a card test that detects elevated pH and trimethylamine; and an office test for vaginal sialidase activity. In contrast, culture of G vaginalis is not specific and should not be used to diagnose BV. In addition, cervical Papanicolaou tests are of limited use in BV diagnosis due to their low sensitivity. Treatment of BV According to CDC guidelines, all symptomatic women with BV should be treated. Clinical goals should be to relieve the signs and symptoms of BV, reduce the risk for infections after abortion or hysterectomy, and reduce the risk for sexually transmitted diseases. The recommended treatment regimens for BV are 1. 'oral' metronidazole 500 mg twice a day for seven days; 2.metronidazole gel .75%, one full applicator (5 g) intravaginally, once a day for five days; or 3.clindamycin cream 2%, one full applicator (5 g) intravaginally, at bedtime for seven days. The oral and gel formulations of metronidazole are similar in efficacy while the clindamycin cream seems to be less effective. Differential Diagnosis of Bacterial Vaginosis Diagnostic Criteria Normal Bacterial vaginosis Trichomoniasis Candidiasis Vaginal discharge Clear or white, flocculent Thin, homogeneous, milky white, adherent to vaginal walls Diffuse, yellow-green White, cottage cheese-like Amine odor on KOH "whiff" test No Present May be present No Vaginal pH 3.8

­- 4.2 > 4.5 Often > 4.5 Usually < 4.5 Main patient complaints None Malodorous discharge Discharge (possibly malodorous), vulvar irritation, dysuria Discharge, vaginal soreness, vulvar burning, pruritus, dyspareunia, and external dysuria Microscopy findings Large concentration of lactobacilli Clue cells, no white blood cells Trichomonas vaginalis Budding yeast or pseudohypha on KOH test KOH, potassium hydroxide. Note* the > 'sign' means more than or higher, and the < 'sign' means less than or lower, DT The following alternative regimens also are noted in the CDC guidelines, with the warning that they have a lower efficacy than the recommended treatments: 1. a single dose of oral

metronidazole 2 g; 2. oral clindamycin 300 mg twice daily for seven days; 3. or clindamycin ovules, 100 g intravaginally, once at bedtime for three days. Consideration of the patient's form of birth control should be taken into account as clindamycin cream and ovules may weaken latex condoms and diaphragms. With oral metronidazole treatment, alcohol consumption should be avoided during treatment and for 24 hours thereafter because of the potential for drug interaction. Currently, no evidence exists to support the use of exogenous (external) lactobacilli, such as those found in yogurt. (Note* I too have read that in several places since the yogurt is NOT the type or strain of lactobacilli that needs to be replaced) Dee Ongoing studies are investigating the use of vaginal lactobacilli

suppositories in addition to oral metronidazole as a BV treatment. Alternative therapies, such as acidophilus pills administered orally or vaginally, garlic pills, and boric acid have little evidence to support their use. (though the garlic pills & boric acid are very beneficial for yeast infections in 'my' opinion, Dee) In fact, these agents are unlikely to be beneficial for patients, may increase treatment costs, and may cause irritation and aggravate vaginal symptoms.11 Recurrence poses a major challenge in the treatment of BV. An estimated 30% of women will experience a recurrence of BV within three months of successful treatment, and 80% within nine months.12 The cause of recurrence is unclear, but it has been hypothesized that persistence of pathogens and failure of lactobacilli to recolonize may play a role. It also has been suggested that women may be reinfected with BV flora by a sexual partner. However, while BV is associated with sexual activity, treating male sexual partners has not shown efficacy in preventing BV recurrence or relapse and is not recommended by the CDC. There are currently no FDA-indicated treatments for recurrent BV. However, maintenance therapy has been proposed by some investigators as one strategy to treat women with recurrent BV. Sobel and colleagues conducted a small placebo-controlled pilot study of .75% metronidazole vaginal gel in women with BV. All of the participants received the drug twice daily for 10 days (twice the usual length of treatment), and then were randomized to twice- weekly applications of the

drug or placebo for the remainder of the three-month study period. The proportion of women who remained symptom-free at the end of the study was more than twice as high in the metronidazole vaginal gel group as in the placebo group (83% vs 33%). The mean time to recurrence was markedly longer with metronidazole vaginal gel (5.7 vs 2.8 months with placebo). ================== Some other links that might be beneficial. http://www.journals.uchicago.edu/JID/journal/issues/v192n8/34982/34982.text.html?erFrom=-731060343167827249Guest http://www.hu.liu.se/pub/jsp/polopoly.jsp?d=3454 & a=26166 http://www.ajcn.org/cgi/content/full/73/2/437S Dee~