General Overview
Gardnerella vaginalis formerly known as Corynebacterium vaginale or Haemophilus vaginalis.
It causes bacterial vaginosis. Moreover, it may cause cervical cancer and infections in urinary tract.
G. vaginalis is a non-motile bacteria which is non-spore forming and microaerophilic.
It is a gram-variable coccobaccilus.
However, in the cell wall, it contains lipopolysaccharide. Because of that it visible as Gram-negative.
It causes bacterial vaginosis along with Mobiluncus species.
Bacterial vaginosis is characterized by a malodorous vaginal discharge and clue cells.
Clue cells are the vaginal epithelial cells covered with G. vaginalis bacteria.
vaginalis cultured on various media, such as Columbia agar.
Colistin and Nalidixic acid are the selective agent containing in Columbia agar.
Plates are incubated in 5–10% carbon dioxide at 35–37°C for 2–3 days.
On blood agar containing human erythrocytes, the organism produce β-haemolytic colonies.
They are oxidase negative and catalase negative.
For the presumptive identification, fermentation of starch and hydrolysis of hippurate are important.
PCR test are also available for the identification of the organism.
Whiff test or amine odour test is positive.
Here vaginal discharge is treated with 10% KOH and positive Whiff test gives a strong fishy odour.
However, this test is not specific for bacterial vaginosis.
Diagnosis should be done with other laboratory results.
Proteolysis done by G. vaginalis produce nitrous products like cadavarines and putrescines.
They contribute to characteristic fishy odour resulting from these infections.
For the multiplication of the organisms metabolic iron is acquired by lysing human red cells.
In addition, they can get ferric iron from human lactoferrin.
Various mucinases are produced by these organisms.
Mainly they produce sialidase and proline dipeptidase.
They damage the mucosa of vagina and invade it. Patients produce IgA antibodies.
However, serological diagnosis procedures are not done as they are still in research level. Â
Treatment
Metronidazole is the drug used for the treatment of this infection.
Other Important features
There is a higher incidence of preterm deliveries in the women with bacterial vaginosis and, higher incidence of morbidity and mortality in their newborn babies.Â
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