Microbiology in practice

Question 1

What are the two functions of the microbiology lab?

Answer 1

Clinical- to diagnosis of the infection for the patient, facilitating treatment.

Epidemiological- we want to keep track of microbial infections so that we have a baseline. This lets us know when there is an outbreak.

Question 2

Name pathogens associated with periodontal disease.

Answer 2

A.a

P.gingivalis.

Question 3

Name some pathogens associated with endodontic infections?

Answer 3

Polyphoromonas Endodontalis

Fusobacterium nucleatum

Question 4

Name and compare the two main candida yeast?

Answer 4

Candia albicans- this is sensitive to fluconazole

Candida glabrata- this is resistant to fluconazole.

Question 5

Classify this candidosis.

Answer 5

This is pseudomembranous candidosis e.g. thrush.

Question 6

Classify this candidosis.

Answer 6

This is erythematous candidosis e.g denture stomatitis.

Question 7

Classify this candidosis.

Answer 7

Hyperplastic candidosis e.g. candida leukoplakia.

Question 8

What is our go to treatment for candida?

Answer 8

Oral hygiene instruction and topical Chlorohexidine.

Question 9

How do we treat a patient with candida who:

• is Immunocompetent
• Has good oral hygiene

Answer 9

Any topical or systemic antifungal.

Question 10

How do we treat a patient with candida who:

is Immunocompetent

Has dry mouth?

Answer 10

Topical antifungal.

Question 11

How do we treat a patient with candida who:

• Is Immunocompetent
• Has a large erosive lesion.

Answer 11

Systemic antifungal AND topical antifungal/ chlorohexidine rinse.

Question 12

How do we treat any immunocompromised patient with candida?

Answer 12

Systemic antifungal AND topical antifungal/ chlorohexidine rinse.

Question 13

What is denture induced stomatitis ?

Answer 13

A mixed infection of bacteria and yeast caused by wearing a denture all the time. This causes inflammation of the gums.

Question 14

How do we treat denture stomatitis?

Answer 14

Brush the palate daily.

Clean the denture by soaking it in chlorohexidine mouthwash or sodium hypochlorite (acrylic) for 15 minutes twice a day.

Question 15

What is angular cheilitis?

Answer 15

A fungal infection found at the corner of your mouth.

Question 16

How do we treat angular cheilitis?

Answer 16

Antifungal- 2% miconazole topical for 10 days.

Antibiotic ointment- Sodium fusidate applied 4 times a day for 10 days.

Question 17

What is pseudomembranous candidosis?

Answer 17

A candida infection of the mouth that occurs in individuals with predisposing factors. e.g. antibiotic use, local corticosteroids. immunodeficiencies, nutritional deficiencies.

Question 18

How do we manage pseudomembranous candiosis?

Answer 18

Management of the biofilm:

Cleaning the palate (covered in white plaques that can be washed away- using

• toothbrush
• Gauze
• Corsodyl mouthwash/ gel.

Removing the denture at night.

Only if the first line management fails-

Use Miconazole (unless patient is on warfarin- increased anticoagulant effect/ or statins- increased myopathy risk)

Nystatin- if the patient is on warfarin.

Question 19

What is hyperplastic candiosis?

Answer 19

This cannot be scraped off. It grows into the tissue and should be tested for a malignancy.

Question 20

What is a bacteria associated with secondary endodontic disease and describe a virulence factor

Answer 20

Polyphoromonas Endodontalis.

Which produces lipopolysaccharide endotoxin

Question 21

Discuss the different antifungals and how they work

Answer 21

Topical- Miconazole oromucosal gel- inhibits the enzyme used to produce ergosterol (part of the cell membrane)

Systemic- Fluconazole- inhibits ergosterol formation in fungi.

If any of above are contraindicated

Nystatin- interacts with the fungal membrane sterols physiochemically.

Question 22

How can candida become resistant?

Answer 22

Altering the target site to prevent azoles binding.

Altering the composition of the cell membrane to prevent insertion of polyene into the cell membrane.