(IX)MicroB Bacteria Little or no peptidoglycan (4)*Mycoplasma pneumoniae

Question 1

Characterize (3) : Mycoplasma

Answer 1

(1) Gram variable pleomorph
(2) No cell wall
(3) Cholesterol in cell membrane

Question 2

Mycoplasma and Chlamydia are unique in that they […] and are thus naturally resistant to […]

Answer 2

Mycoplasma and Chlamydia are unique in that they have no peptidoglycan in cell envelopes and are thus naturally resistant to penicillins, cephalosporins and glycopeptides

TLDR, they are resistant to EVERYTHING covered in the bacteria cell wall inhibitors lecture (Beta Lactams and glycopeptides)!!!

Question 3

Mycoplasma hominis infection:

Clinical presentation:
[…]

Answer 3

Mycoplasma hominis infection:

Clinical presentation:
1. UTI (acute pyelonephritis), renal stones
2. vaginosis, Pelvic inflammatory disease
3. Post-abortion/post-partum fever, premature neonatal meningitis, neonatal RTI
4. post transplant infection (sternal wound infection, septicemia)

Question 4

What are some examples of Mycoplasma spp?

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Answer 4

What are some examples of Mycoplasma spp?

M. pneumoniae (walking pneumonia)
M. genitalium (urogenital)
M. hominis (immunocompromised)

Also known as the smallest “free living” organisms

Question 5

What are the lab diagnosis for M. pneumoniae?

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Answer 5

What are the lab diagnosis for M. pneumoniae?

• Tests are actually not usually done? Just give empirical therapy.
• But if you really want to:

1. Serology immunoassay
   - IgM in children, not for adults (Cold agglutination)
   - Paired acute and convalescent sera (complement fixation test)
2. PCR always reliable as heck but also expensive as heck.

NOT culture!! To damn difficult.

Question 6

What is the classic clinical manifestation of M. pneumoniae infections?

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Important complication of M. pneumoniae infection?

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The severe forms of the disease arises in the […]

Answer 6

What is the classic clinical manifestation of M. pneumoniae infections?

• Walking (atypical) pneumonia: most do not become seriously ill - Upper and lower respiratory tract infections (commonest in children and teenages)
• agents for transmission
• Children: Paroxysmal cough (may be confused with whooping cough)

Important complication of M. pneumoniae infection?

Steven Johnson syndrome (7%!!!) (hypersensitivity similar to TEN)

The severe forms of the disease arises in the immunocompromised or sickle cell disease

Other complications: joint pain, encephalitis, meningitis, hemolytic anemia, myocarditis, pericarditis

“For unclear reasons, up to 7% of patients infected with Mycoplasma pneumonia can develop erythema multiforme or Stevens-Johnson syndrome, a severe skin reaction characterized by erythematous vesicles and bullae over the mucocutaneous junctions of mouth, eyes and skin.”

Question 7

What is the treatment for walking pneumonia (aka “atypical coverage”)? (IMPT)

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Answer 7

What is the treatment for walking pneumonia (aka “atypical coverage”)? (IMPT)

• Macrolides (Erythromyin, clarithromycin, azithromycin)
• Tetracyclines (doxycycline)
• Fluoroquinolones (ciprofloxacin, levofloxacin)

HH: “Crows, Wheels, Flowers”-crows =macrolides wheels=tetracyclines flowers=fluoroquinolones

Recall that we use Macrolides + Tetracyclines for Chlamydia~ But that one we couple it with ceftriaxone to cover N. gonorrhoeae also!

Pls pls pls don’t use cell wall agents (penicillins, cephalosporins, glycopeptides)