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in controlling UTIs in up to 73 percent of the cases.
111
Asahara et al.
112
reported
that mice previously infected with
E. coli
showed a decrease in
E. coli
growth and
inflammation after local application of heat-killed
L. casei
Shirota.
18.3.2.4 Bacterial Vaginosis (BV)
The vagina and its microflora form a finely balanced ecosystem. Disruption of
this ecosystem can lead to a microbiological imbalance and symptoms of vagino-
sis.
113,114
Earlier considered to be a mere annoyance, vaginosis is now being examined
for a role in serious conditions including pelvic inflammatory disease, pregnancy-
related complications (low-birth-weight babies), and increased susceptibility to
AIDS infection. The organisms associated with BV include a variety of anaerobic
Gram-negative rod-shaped bacteria, namely,
Gardnerella
,
Mobiluncus
,
Bacteroides
,
and possibly
Fusobacterium
,
Prevotella
, Pepo
Streptococcus
,
Porphyromonas,
and
Mycoplasma
species.
115
Elucidation of pathogenic mechanisms of BV indicates a role
of inflammatory cytokines and antibodies to cytolysins. These factors are not easily
resolved by antibiotic treatment, thus traditional approaches to patient management
like probiotic therapy are being reevaluated.
116 -118
The failure of antibiotic therapy to
control bacterial vaginosis reflects organisms already having ascended the uterus or
the antibodies being unable to eradicate pathogen biofilms and negate their sialidase
activity. Reid and Bocking,
119
along with others,
120
have drawn attention to reduced
presence of
Lactobacilli
(especially those producing hydrogen peroxide) in patients
with BA. Standard antibiotic therapy for BV with metronidazole is quite ineffective
in that more than 30 percent of women have yeast vaginitis after therapy and more
than 50 percent get a recurrent BV infection within 3 to 6 months.
121
A study constituting 13 women showed that consumption of yogurt containing
L.
acidophilus
decreased the incidence of
C. albicans
yeast infections. Hydrogen per-
oxide (H
2
O
2
) production is a key factor in resisting BV disease.
122
H
2
O
2
-producing
strains of lactobacilli have been found in 61 percent of pregnant women with nor-
mal flora, and in only 5 percent of women with BV. The H
2
O
2
has been shown to
be toxic to BV-causing organisms, namely,
Gardnerella vaginalis
and
Prevotella
bivia
.
115
Comparable results were obtained in open and placebo-controlled studies,
in which lyophilized
L. acidophilus
was applied locally or
L. acidophilus
yogurt was
given orally.
123,124
In these studies, success rates for control of bacterial vaginosis or
Candida
vaginitis ranged from 57 to 87 percent in the probiotic group and from 0 to
22 percent in the control group.
124
Various molecular methods have shown
L. crispatus
and
L. johnsonii
to be the
most common vaginal isolates from “normal” women of childbearing age.
125
The
administration of
L. rhamnosus
GR-1 in combination with
L. fermentum
B-54 and
RC-14 by mouth and intravaginally have been shown to be safe and to reduce the
risk of UTIs, BV, and yeast vaginitis.
126
As with urogential pathogens,
Lactobacilli
ascend from the rectum into the vagina and, subsequently, alter the microenviron-
ment and potentially modulate the immunologic status of the host such that a normal
vaginal flora is more often restored and retained.
126,128
