Bacterial Vaginosis: Diagnostic Criteria

Bacterial Vaginosis (BV) is a disease associated with vaginal microbiota. In the reproductive age group, women have microbiologically very complex vaginal environment. The healthy vagina should have an abundance of Gram-positive rods (Lactobacillus spp.), low pH (<4.5) and absence of both facultative and obligatory anaerobic Gram negative bacilli.

By definition, BV is the inflammation of vaginal mucosa together with clinical symptoms of abnormal vaginal discharge, itching, burning sensation and discomfort. Vaginal environment disturbance can be caused by many infectious and non-infectious causes of. Among the infectious causes, bacterial vaginosis is the commonest reproductive tract infection of reproductive age group women. Gardnerella vaginalis, Mobiluncus spp., Mycoplasma hominis, Bacteroides spp., and certain anaerobic bacteria are among the mixed bacterial flora that replaces the usual vaginal flora. BV has several adverse effects therefore timely diagnosis and treatment is of great important.

Amsel's clinical criteria and Nugent's microscopic criteria are the most widely used techniques for BV diagnosis. Nugent scoring system is considered as gold standard method due to its reproducibility and high sensitivity but needs laboratory equipment and specialists. On the other hand, Amsel’s criteria are rapid, inexpensive and simple. Comparing Amsel's criteria to the Nugent scoring system, the sensitivity, specificity, positive predictive value and negative predictive value were 50%, 98.2%, 87.5%, and 88.8% respectively. 

Even though culture is thought to be the gold standard approach for identifying many bacterial infections, it cannot be a reliable way to identify BV. Although it can be difficult to diagnose BV accurately, traditional diagnostic techniques like Amsel's criteria and Nugent's scoring systems continue to be the most practical and cost-effective choices.

References:

1.Rao S, Pindi DKG, Rani DU, Sasikala DG, Kawle DV. Diagnosis of bacterial vaginosis: Amsel’s Criteria vs Nugent’s scoring. J Appl Med Sci. 2016;4(6):2027–31.

2.Amsel R, Totten PA, Spiegel CA, Chen KC, Eschenbach D, Holmes KK. Nonspeciic vaginitis: diagnostic criteria and microbial and epidemiologic associations. Am J Med. 1983;74(1):14–22.

3.Nugent RP, Krohn MA, Hillier SL. Reliability of diagnosing bacterial vaginosis is improved by a standardized method of gram stain interpretation. J Clin Microbiol.1991;29(2):297–301.

4.Bhujel et al. Comparative study of Amsel’s criteria and Nugent scoring for diagnosis of bacterial vaginosis in a tertiary care hospital, Nepal. BMC Infect Dis.2021; 21:825