Mycoplasma and Legionella

Question 1

2 genre within the class Mollicutes

Answer 1

Mycoplasma and Ureasplasma

Question 2

Cell Characteristics of Mollicutes

Answer 2

No cell wall so the shape is not well defined and the flexible cells can pass through filters, the outer boundary is a cytoplasmic membrane containing sterols

Question 3

What do Mollecutes require in growth media

Answer 3

Mycoplasma and Ureasplasma require sterols because they are unable to synthesize them and Ureasplasma requires urea for metabolic energy

Question 4

Why must you stain Mollecutes colonies on the growth media?

Answer 4

The cells are too small to be seen with conventional dyes

Question 5

Name 3 Mollecutes species that cause Human diseases.

Answer 5

1.Mycoplasma pneumoniae cause walking pneumonia/community acquired pneumonia/primary atypical pneumonia, 2.Mycoplasma hominis causes post-partum fever and pelvic inflammatory disease 3. Ureasplama urealyticum cuases non-gonococcal urethritis in men, post-partum fever and infertility in women, and respiratory disease in infants

Question 6

Clinical course of Mycoplasma Pneumoniae (community acquired pneumonia)

Answer 6

2 week incubation, early phase with fever headache chills and nonproductive cough, and late phase with lower lobe pulmonary infiltrates

Question 7

How Does Mycoplasm pmeumoniae likely destroy epithelial cells?

Answer 7

Attaches to cell membrane and remains extracellular then inhibits host cell catalases/proteases that allow host/bacteria generated H2O2 to damage the cell

Question 8

Compare the sensitivity and specificity of the serologic tests for Mycoplasma pneumoniae

Answer 8

Sensitivity: PCR better than EIA better than Immunofuorescence Specificity:Immunofluorescence/EIA better than PCR

Question 9

How are Mycoplasma pneumoniae and Legionella pneumophila transmitted?

Answer 9

Mycoplasma: Inhalation of respiratory aerosols Legionella: Nosocomial infections from faucets, shower heads, cooling towers etc.

Question 10

How do antimicrobials affect Mycoplasma pneumoniae?

Answer 10

Antimicrobials that affect cell wall synthesis have no effect, therapy may lower infectivity but not symptoms

Question 11

Why is incidence of Mycoplasma hominis and Ureasplasma urealyticum uncertain?

Answer 11

Chlamydia is found in the same areas and responds to the same antimicrobials so they are often misdiagnosed

Question 12

What species causes Legionellosis

Answer 12

Legionella pneumophila Type 1

Question 13

Where do Legionella grow and what is used in their growth media?

Answer 13

They grow in water habitats and their growth media has charcoal for detoxification and yeast extract for nutrients

Question 14

What cell type is Legionella

Answer 14

Gram negative Rod

Question 15

What must you use instead of a Gram stain for Legionella

Answer 15

Carbol-fuchsin counterstain or half-a-Gram stain without a decolorizing agent

Question 16

Clinical Course of Legionella pneumonia

Answer 16

2 to 10 day incubation then 1 day predrom with myalgia malaise and headache then acute disease with fever, shaking, non-productive cough, GI symptoms, and patchy infiltrates that may consolidate

Question 17

What lab test is the most reliable and rapid for Legionella pneumonia

Answer 17

test a urine sample for Legionella pneumophila type 1 antigen, results in 48 hours and positive in 90% of patients

Question 18

Antimicrobial therapy for Legionellosis

Answer 18

Broad spectrum antibiotics are ineffective, Macrolides and fluoroquinolones are most effective