Micromodules: Gram negative Cocci

Question 1

What are some common gram negative cocci Genus?

Answer 1

Neisseria
Moraxella
Chlamydiaceae family: Chlamydia, Chlamydophilia
Mycobacterium
Treponema
Mycoplasma/urea

Question 2

Where do you find Neisseria species on the human body?

Answer 2

As commensals of the respiratory tract and the female genital tract

Question 3

What are the two most important Neisseria species in regards to human disease, and which disease do they cause?

Answer 3

Neisseria meningitidis: causes meningococcal, meningitis and bacteraemia
Neisseria gonorrhoeae: causes gonorrhoea

Question 4

What is the appearance of Neisseria species?

Answer 4

Gram negative (clearly)
Diplococci, some coccobacilli (shape between a sphere and a rod)

Question 5

Why are members of the Chlamydiaceae not seen on a gram stain?

Answer 5

They lack a peptidoglycan wall

Question 6

What type of parasite are the Chlamydiaceae family?

Answer 6

Obligate intracellular

Question 7

What disease does Chlamydia trachomatis cause?

Answer 7

Trachoma (WHOOO)

Chlamydia

Question 8

What disease does Chlamydophilia pneumoniae cause?

Answer 8

Lower respitory tract infections:
Bronchitis
Pharyngitis
Community acquired pneumonia

Question 9

In which animal does Chlamydophilia psittaci originate from?

Answer 9

Birds/mammals, and causes parrot fever

Question 10

What type of staining is used on Mycobacterium and why?

Answer 10

Ziel-Neelsen stain, because they have a thick cell wall with lots of mycolic acid. This also makes them hardy and resistant to drying

Question 11

Which pathogen causes Tuberculosis?

Answer 11

Mycobacterium tuberculosis

Question 12

What is the appearance of Treponema pallidum, what kind of pathogen is it and what disease does it cause?

Answer 12

It’s a spirochaete which although gram negative, cannot be seen on gram stain as it is too thin. It is an obligate intracellular pathogen and causes Syphilis.

Question 13

What is used to detect syphilis and why?

Answer 13

NAAT - nucleic acid amplification test. This used because of how long it takes to grow syphilis: about a month

Question 14

How is veneral syphilis contracted?

Answer 14

Usually via direct skin or mucous membrane (anogenital most common) contact with someone who has first or second degree syphilis

Question 15

What is a Chancre and where do you find them?

Answer 15

A chancre is a painless ulcer with firm, raised edges that is found at the site of inoculation of syphilis. It contains replicating spirochaetes and is infectious

Question 16

How does second degree syphilis usually start and what are its systemic symptoms?

Answer 16

With a skin rash, usually on palms or soles of feet.

Systemic symptoms include fever, pharyngitis, alopaecia, weight loss, fatigue and muscle aches

Question 17

How big are myco/ureaplasmas?

Answer 17

The smallest form of free-living life

Question 18

What are the four antibiotics used to treat tuberculosis?

Answer 18

Isoniazid
Rifampicin
Pyrazinamide
Ethambutol

Question 19

What are the three species of Mycoplasma we need to know about?

Answer 19

Mycoplasma pneumoniae
Mycoplasma hominis
Mycoplasma genitalium

Question 20

What disease do Mycoplasma pneumoniae cause?

Answer 20

Lower respiratory tract infections such as tracheobronchitis, bronchiolitis and pneumonia (walking pneumonia because they don’t appear toxic)

Question 21

What disease does Mycoplasma hominis cause?

Answer 21

PID
Chorioamnionitis and prem labour
Adverse pregnancy outcomes
Postpartum fever and post abortal fever

Question 22

What disease does Mycoplasma genitalium cause, and where is it found?

Answer 22

Causes non gonnococcal urethritis in men

Causes cervicitis and PID in women

Question 23

WHat disease does Ureaplasma urealyticum cause?

Answer 23

Essentially the same as Mycoplasma hominis:
Chorioamnionitis, premature labour and adverse pregnancy outcomes, post partum and post abortal fevers
Non-gonnococcal urethritis in men