Association of Bacterial Vaginosis and Human Papilloma Virus Infection With Cervical Squamous Intraepithelial Lesions

Wissam Dahoud, MD; Claire W. Michael, MD; Hamza Gokozan, MD; Amelia K. Nakanishi, MD; Aparna Harbhajanka, MD


Am J Clin Pathol. 2019;152(2):185-189. 

In This Article

Abstract and Introduction


Objectives: Human papillomavirus (HPV) is known to be associated with squamous intraepithelial lesions (SILs). However, there is limited and conflicting literature on the relationship between bacterial vaginosis (BV) and SIL. The aim of this study is to determine the prevalence of BV and evaluate the association between BV and SIL.

Methods: A retrospective study was performed on 10,546 cases between 2012 and 2017. HPV results were available in 7,081 cases.

Results: BV was present in 17.6% of cases. There was significant association between BV, positive HPV infection, and high-grade SIL. BV patients with negative HPV infection showed more squamous abnormalities than BV-negative HPV-negative patients.

Conclusions: We found there is a significant association between BV and SIL. BV is more common among patients with HPV infection and is independently associated with squamous abnormalities in cervical smears and surgical follow-up.


In the past, cervical cancer was the most common cause of cancer deaths in women in the USA and it is still a major cause of mortality and morbidity worldwide.

Many factors have been associated with increased risk for squamous intraepithelial lesions (SILs) and cervical cancer, including early age of first sexual intercourse, cigarette smoking, multiple sexual partners, and low socioeconomic status. However, human papillomavirus (HPV) is the cause of cervical cancer and its precursor lesions, that is, SIL and cervical intraepithelial neoplasia (CIN).[1,2] Most HPV infections are asymptomatic, with up to 90% of cases clearing within 1 or 2 years and it persists in only 10% to 20% of infected females.[3,4]

Bacterial vaginosis (BV) is a treatable condition characterized by disruption of the vaginal environment and replacement of the normal lactobacilli-dominant vaginal flora by a mixture of anaerobic organisms.[5] BV is mainly found in women of child-bearing age, which is suggested to be related to hormonal changes (vaginal pH changes) and sexual behavior. BV has been frequently found in SILs of low grade and it is suggested that BV could be important in the development of SIL. One suggested mechanism is that carcinogenic nitrosamines could be produced from abnormal flora and stimulate the release of some cytokines, such as interleukin-1B and interleukin-8, and subsequently act on the cervix either independently or together with other agents such as a virus.[6] However, the relationship between HPV16 oncogenes E6 and E7 and the microbiologic environment has been studied in vitro and the expression of these genes was unaltered in the presence of bacteria. This suggests that vaginal microorganisms are unlikely to alter the natural history of HPV-associated cervical neoplasia by influencing HPV oncogene expression.[7]

Previous studies on the relationship between SIL and BV have produced conflicting results.[5,8–12] The goal of this study was to determine the prevalence of BV diagnosed in ThinPrep from different age groups and evaluate the impact of BV on the presence of HPV infection and development of SILs.