Can Bacterial Vaginosis Progress To Chlamydia?

In this article, we will take a close look at Bacterial Vaginosis and Chlamydia, two common infections. We will explore their causes, symptoms, treatments, and the potential link between them. Specifically, we will address the question: Can Bacterial Vaginosis progress to Chlamydia?

Author - Jakub Hantabal

Postgraduate student of Precision Cancer Medicine at the University of Oxford, and a data scientist.

Jakub used MediSearch to find sources for this blog.

MediSearch gives instant answers to medical questions based on 30 million scientific articles.

Bacterial Vaginosis: An Overview

Bacterial vaginosis (BV) is a common infection in women of reproductive age. It is a complex bacterial infection characterised by a disturbance of the normal vaginal flora (microbiome) and an overgrowth of anaerobic bacteria.

The healthy vagina is populated by lactobacilli, which maintain the pH of 4.5. This is an acidic environment (fun fact - the pH in the vagina is comparable to that of beer), which is inhabitable for bacteria. BV is characterised by a decrease in the population of these protective lactobacilli, resulting in an increase of pH (higher number = less acidic), allowing opportunistic bacteria to start growing and cause BV.

Common bacteria growing in BV include the phyla Prevotella, Gardnerella, Mobiluncus, or the species Escherichia coli, among others.

While the consequences of BV (increase in pH and increase in diversity of the vaginal flora) are known and characterised, questions remain about the exact causes of BV [1].

Signs and Symptoms of BV

In 50 to 80% of patients, BV can be asymptomatic, meaning it does not present with any signs and symptoms.

If BV presents with symptoms, the most common symptom is vaginal discharge, which is thin and grey, white or green in colour. The discharge can have a foul, "fishy" smell. Some women may also experience vaginal itching and a burning sensation during urination [2].

Diagnosis of Bacterial Vaginosis

There are two commonly used diagnostic workflows for BV: the Amsel and the Nugent method.

The Amsel diagnostic criteria include:

Presence of a characteristic discharge,
Vaginal pH greater than 5.0,
A positive KOH amine test (this detects amines, which are molecules required for bacterial growth; these are also the cause of the foul odour with BV).

The Nugent method is more heavily based on detecting bacteria, involving a microscopic examination of Gram-stained smear of the vaginal secretions. Gram staining is a method of differentiating bacteria based on the membrane they have [1, 3, 2].

Treatment for Bacterial Vaginosis

The treatment for BV is based on a course of antibiotics and aims to eliminate the opportunistic bacteria growing in the disrupted microbiome.

Metronidazole (taken orally) or clindamycin (applied vaginally) are common antibiotics used to treat BV. Alternative therapies, such as dequalinium vaginal tablets, are also being explored [1, 3, 4].

However, despite successful treatment, recurrence is common, occurring as early as within 6 months after treatment.

In some cases, completing a diagnostic work-up and treatment may be necessary for your sexual partners, as they may be unknowingly introducing bacteria during sex.

What if BV is not treated?

As with every infection, BV should be promptly resolved. If left untreated, BV can cause serious complications, including:

increased risk of sexually-transmitted infections (such as chlamydia, or more serious infections such as HIV),
pregnancy-related complications such as pre-term labor or pre-term birth,
increased post-operative morbidity,
progression to pelvic inflammatory disease (PID), which can be life threatening [1, 5].

What is Chlamydia?

Chlamydia is a common sexually-transmitted infection (STI). It is a bacterial infection, caused by the bacteria Chlamydia trachomatis. It can affect anyone who is sexually active, and can be transmitted via oral, vaginal or anal sex [6, 7, 8].

Signs and Symptoms of Chlamydia

It is important to acknowledge that a large proportion of patients do not experience any symptoms, and unknowingly spread the infection. This underlines the importance of safe sex practices and regular testing for STIs.

If symptoms do present, they can manifest up to several weeks after sexual contact with an infected person.

The symptoms in women may include:

unusual vaginal discharge,
spotting or bleeding between periods,
pain during sex,
burning sensation during urination,
abdominal and lower back pain [4].

In men, symptoms can include:

discharge from the penis,
burning sensation during urination,
pain and/or swelling in one or both testicles [4].

In both sexes, chlamydia can affect the rectum, presenting with pain, bleeding and/or unusual discharge.

In the throat, chlamydia may present with redness, inflammation or soreness.

Chlamydia may also present in the eyes, with conjunctivitis (pink eye) or discharge / pus [4, 5].

Diagnostic Process for Chlamydia

The diagnostic process involves determining if the bacteria Chlamydia trachomatis are present in a sample. The common samples for chlamydia testing are urine, or swabs from the vagina, cervix, urethra or rectum.

As chlamydia is often asymptomatic, regular screening is important, especially for sexually active people [6, 7].

Treatment for Chlamydia

Chlamydia can be cured with appropriate treatment. As it is a bacterial infection, antibiotics are used, with azithromycin or doxycycline being the frontline options.

It is important to treat both the infected individual and their sexual partner(s) to prevent re-infection. Additionally, it is advised to abstain from sexual activity during the treatment [4, 7].

What if chlamydia is not treated?

If untreated, chlamydia can progress to serious health complications.

In women, the infection can spread to the uterus and fallopian tubes, causing pelvic inflammatory disease (PID), as well as potential infertility and an increased chance of ectopic pregnancy.

In men, chlamydia can progress to epididymitis, a painful complication in the tube that carries sperm, and infertility, though this is very rare.

Both men and women can develop reactive arthritis, which is a type of immune system reaction to a persistent infection. Furthermore, chlamydia can be transmitted from mother to newborn at birth, causing major complications such as pneumonia [8, 9].

[10]

Can BV progress to chlamydia?

It is important to realise that BV and chlamydia are two distinct conditions:

BV is a distuption of the healthy microbiome leading to growth of opportunistic bacteria,
Chlamydia is a bacterial infection by a single pathogen Chlamydia trachomatis [5, 9].

However, some studies have demonstrated an association between BV and chlamydia. Women with BV are more likely to test positive for chlamydia [11]. Additionally, BV in patients with chlamydia has been associated with increased persistence of the infection, meaning that it can complicate treatment [10].