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Year : 2003  |  Volume : 21  |  Issue : 2  |  Page : 124--126

Anaerobes in bacterial vaginosis

A Aggarwal, P Devi, R Jain 
 Department of Microbiology, Govt. Medical College, Amritsar - 143 001, Punjab, India

Correspondence Address:
A Aggarwal
Department of Microbiology, Govt. Medical College, Amritsar - 143 001, Punjab


Four hundred high vaginal swabs were taken from patients attending gynaecology and obstetrics department of Govt. medical college, Amritsar. The patients were divided into four groups i.e. women in pregnancy (Group I), in labour/post partum (Group II), with abnormal vaginal discharge or bacterial vaginosis (Group III) and asymptomatic women as control (Group IV). Anaerobic culture of vaginal swabs revealed that out of 400 cases, 212(53%) were culture positive. Maximum isolation of anaerobes was in group III (84%) followed by group II (56%), group I (36%) and control group (15%). Gram positive anaerobes (69.2%) out numbered gram negatives (30.8%). Among various isolates Peptostreptococcus spp. and Bacteroides spp. were predominant.

How to cite this article:
Aggarwal A, Devi P, Jain R. Anaerobes in bacterial vaginosis.Indian J Med Microbiol 2003;21:124-126

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Aggarwal A, Devi P, Jain R. Anaerobes in bacterial vaginosis. Indian J Med Microbiol [serial online] 2003 [cited 2020 Nov 25 ];21:124-126
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Full Text

Bacterial vaginosis is a condition characterised by raised vaginal pH and milky discharge in which the normal vaginal flora is replaced by a mixed flora of aerobic, anaerobic and microaerophilic species.[1] It may be diagnosed on clinical grounds if minimum three of the four criteria are fulfilled. [2] Microbiology of bacterial vaginosis is complex and involves various organisms such as Gardnerella vaginalis, mixed anaerobes such as Mobiluncus spp., Prevotella spp., Peptostreptococcus spp., Bacteroides spp., Eubacterium spp., Mycoplasma hominis and aerobic organisms, etc.[1]

The aetiology and pathogenesis of bacterial vaginosis is still unclear. There is increasing interest in the importance of the vaginal flora of bacterial vaginosis. Very few studies have been conducted in this part of the country. Therefore, the present study was undertaken to find the prevalence of anaerobic organisms in women suffering from bacterial vaginosis.

 Materials and Methods

The present study was conducted on 400 patients of reproductive age group attending obstetric and gynaecology department of Govt. medical college, Amritsar as out-patients and inpatients. High vaginal swabs were taken from the following groups of patients. Group I, women in first or second trimester of pregnancy including cases of abortion/miscarriage; Group II, women in second or third stage of labour/early post partum period (within 7 days); Group III, consisting of women with complaints of abnormal vaginal discharge; and Group IV, comprising of asymptomatic women (control).

Two vaginal swabs were taken from each patient and transported to the laboratory in the Amies transport medium. While taking swab, colour, consistency and odour of vaginal discharge was noted. The pH of vaginal discharge was measured directly by placing indicator paper for pH range 4.0 to 6.0 on the vaginal wall. Amine odour test was also performed.[3] From one swab wet mount and smears for gram staining were prepared which were examined for presence of pus cells, clue cells, epithelial cells, yeast, Trichomonas vaginalis, gram positive or gram negative organisms. Patients fulfilling minimum 3 out of 4 diagnostic criteria[2] were clinically diagnosed as having bacterial vaginosis.

Second swab was processed by inoculating onto various culture media. Samples were first inoculated into liquid medium i.e. Robertson cooked meat medium, and after incubation for 24 hours subcultures were made on solid media i.e. neomycin blood agar. Metronidazole 5 g disc was placed on each primary anaerobic blood agar plate after inoculation for observing primary sensitivity. Plates were incubated anaerobically in McIntosh Fildes' anaerobic jar for 48 hours. Pure growth of anaerobic organisms was obtained after repeated subculturing and organisms were identified upto the genus level on the basis of standard methods.[4],[5]


The study was conducted to find the anaerobic flora associated with bacterial vaginosis both by clinical signs and laboratory methods.

[Table:1] shows that prevalence of bacterial vaginosis was 68% in group III, 38.6% in group II, 36.4% in group I and 10% in control group.

Out of total 400 cases, 212 (53%) were culture positive for anaerobes. Gram positive anaerobes (69.2%) outnumbered gram negative one (30.8%). Distribution of various anaerobes isolated in all the four groups is shown in [Table:2] which shows that isolation of anaerobes was significant in group III and group II females in comparison to control group IV.


Evidence of association of anaerobic bacteria with bacterial vaginosis is mounting. Different workers have isolated different types of anaerobes in vaginal discharge of different group of patients.[1],[6],[7] In the study by Rosenstein et al[8] anaerobic streptococci were isolated in 74% of patients with bacterial vaginosis, while Bacteroides and other gram negative rods were isolated in 60% of patients. Levison et al[9] isolated Peptostreptocci in 5, Peptococci in 5 and Bacteroides in 6 out of 12 patients with non-specific vaginitis. In the study by Krohn et al[10] Bacteroides species were isolated in 62% and Peptostreptococci in 59% of pregnant women having bacterial vaginosis with three of the four clinical signs[2] positive. Three days after the delivery, anaerobes return where they can cause endometritis and post-partum sepsis.[11]

The difference in type and rate of isolation of anaerobes reflects difference in population under study and different methods of investigations. Moreover vagina is not a single environment, the flora of the lower vagina is related to that of perineum and introitus and differs from that of cervix and fornices. In addition, the physiological state of vaginal mucosa and secretions change with age, menstrual cycle and pregnancy.[12]

Therefore, it can be concluded that anaerobic bacteria are also important pathogens in bacterial vaginosis and most of them can be isolated by using simple media and culture techniques. Their isolation would help the clinicians in appropriate treatment of bacterial vaginosis.


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