Microbiology-Bacterial Vaginosis

Question 1

Inflammation of the vaginal epithelium

Answer 1

Vaginitis

Question 2

Inflammation of the endocervix + mucopurulent discharge

Answer 2

Cervicitis

Question 3

Vaginal irritation, pruritis and odor w/o PMN response

Answer 3

Vaginosis, due to disruption of normal flora

Question 4

Typical agent involved in vaginal yeast infections

Answer 4

Candida albicans

Question 5

Vaginal inflammation associated with STDs

Answer 5

Trichomonas

Question 6

Most common etiology of vaginitis

Answer 6

Bacterial vaginosis 40-50% of cases

Question 7

A woman presents with lower abdominal pain, a feeling of fullness and vaginal pruritis. Physical exam shows red vaginal walls and labia with a thin, grayish/white odorous discharge. What are significant risks will she be at risk for if this condition is not resolved?

Answer 7

Preterm delivery, postpartum infection, post-surgical infection, increased risk of STDs, PID and salpingitis.

Question 8

A woman presents with lower abdominal pain, a feeling of fullness and vaginal pruritis. Physical exam shows red vaginal walls and labia with a thin, grayish/white odorous discharge. What could be causing her condition?

Answer 8

Loss of lactobacilli + proliferation of anaerobes like mobiluncus or gardnerella vaginalis happens with bacterial vaginosis. This can be a consequence in changes in hormone status (low estrogen = loss of lactobacilli), presence of semen (alkalinizes vagina) and abx/douching that alters normal flora.

Question 9

What bacteria are present in these different gram stains?

Answer 9

Note the large, pleomorphic gram-positive rods indicating lactobacilli. These are present in healthy normal vaginal flora.

Question 10

How does lactobacilli repress growth of chlamydia and gonorrhea?

Answer 10

Bacteriosins are antibiotic secretions from lactobacilli.

Question 11

Normal vaginal pH

Answer 11

< 4.5. This is the range when lactobacilli thrive, they die when pH > 5.

Question 12

A woman presents with lower abdominal pain, a feeling of fullness and vaginal pruritis. Physical exam shows red vaginal walls and labia with a thin, grayish/white odorous discharge. 10% KOH whiff test was + for amine (fishy) smell. Vaginal pH > 5. Gram stain is shown below. What is your diagnosis?

Answer 12

Note the clue cells (epithelial cells covered with gram + rods: gardnerella vaginalis). This is an indication of bacterial vaginosis.

Question 13

A woman presents with lower abdominal pain, a feeling of fullness and vaginal pruritis. Physical exam shows red vaginal walls and labia with a thin, grayish/white odorous discharge. Vaginal pH > 5. Culture is shown below. What is your diagnosis?

Answer 13

Note the beta-hemolytic pattern on human blood agar with colonies susceptible to metronidazole disk. This is typical of gardnerella vaginalis.

Question 14

A woman presents with lower abdominal pain, a feeling of fullness and vaginal pruritis. Physical exam shows red vaginal walls and labia with a thin, grayish/white odorous discharge. 10% KOH whiff test was + for amine (fishy) smell. Vaginal pH > 5. How do you treat her?

Answer 14

Bacterial vaginosis is treated with metronidazole gel or pills. Note that metronidazole is specific for treating anaerobes.

Question 15

Side effect of metronidazole

Answer 15

Liver toxicity when used with alcohol

Question 16

Effect of treating the male urethra for gardnerella vaginalis in preventing bacterial vaginosis

Answer 16

Ineffective

Question 17

Why don’t we recommend probiotics for bacterial vaginosis?

Answer 17

Species are not present in probiotics that colonize a healthy vagina. This may work because normal flora in the vagina come from the GI tract.

Question 18

What oral condition is associated with bacterial vaginosis?

Answer 18

Periodontal disease

Question 19

A woman presents with vulvo-vaginal itching and burning on urination. Physical exam reveals a thick, white, cottage cheese-like discharge. What are risk factors for her condition?

Answer 19

Antibiotic therapy, change in hormone status (menarche), diabetes mellitus and immunodeficiency are risks for Candida vaginitis.

Question 20

Why can yeast infections occur with normal flora?

Answer 20

They love a low pH environment created by the normal flora.

Question 21

A woman presents with vulvo-vaginal itching and burning on urination. Physical exam reveals a thick, white, cottage cheese-like discharge. What would you expect to see on lab tests?

Answer 21

Candida is a yeast infection and shows budding yeast or hyphae.

Question 22

Treatment for yeast infection in women who are diabetic, pregnant or HIV?

Answer 22

Oral fluconazole. They will have trouble clearing a systemic infection with the normal “azole” topical OTC creams.

Question 23

What bacteria is this and where does it colonize?

Answer 23

Trichomonas vaginalis. This bacteria is an aerotolerant anaerobe that utilizes the vagina as a reservoir.

Question 24

Why do we rarely hear about trichomoniasis as an STD?

Answer 24

Although prominent, it is usually asymptomatic

Question 25

A woman presents with a yellow-green thick mucopurulent vaginal discharge, abdominal pain and pruritis. Labs reveal a vaginal pH > 5. She has had sex with several different partners in the past few months. What are risks associated with her condition?

Answer 25

Trichomonas carries risk of premature birth, postpartum complications and increased risk of other STDs (especially HIV).

Question 26

What differs bacterial vaginosis from trichomoniasis?

Answer 26

There is a robust inflammatory response with PMN infiltrate in trichomoniasis, which is absent in BV.

Question 27

What makes women with trichomoniasis at higher risk for HIV?

Answer 27

Cell-meidated response -> CD4+ infiltrate (susceptible to HIV) to vagina -> Vaginal mucosa pinpoint hemorrhages allows for infection site -> trichomonas degrades leukocyte protease inhibitor that normally blocks HIV cell attachment -> Trichomonas increases shedding of HIV in infected individuals

Question 28

Why can you get recurrent infection with trichomonas?

Answer 28

Antigenic variation: they are infected by viruses that affect how their surface proteins are expressed. They also produce proteases that degrade antibodies.

Question 29

Diagnosing trichomonas

Answer 29

Visualization on wet mount, urine dipstick, PCR or culture.

Question 30

A woman presents with a frothy yellow-green mucopurulent vaginal discharge, abdominal pain and pruritis. Labs reveal a vaginal pH > 5. She has had sex with several different partners in the past few months. How do you treat her?

Answer 30

Single oral dose of metronidazole, can use topical also. Note that the oral dose is recommended in pregnant women and treatment of both partners is indicated.

Question 31

Why is metronidazole effective against anaerobes?

Answer 31

Reducing (acidic) environments activate the drug -> then it attacks the DNA. They are effect where redox potential is low in anaerobic bacterial and protozoan infections occur.

Question 32

Aerobic vaginosis, risk associated with it

Answer 32

E. coli or group B strep colonization of the vagina. Common causes of neonatal infections.