Morphology: Obligate intracellular bacterium; biphasic life cycle (infectious elementary body / replicative reticulate body). No peptidoglycan — β-lactams inactive.
Typical drugs
- #1Azithromycin— First-line; same regimen as Mycoplasma.
- #2Doxycycline— Equally effective.
- #3Levofloxacin— Respiratory FQ as monotherapy in CAP.
- #4Moxifloxacin
Empiric therapy when resistant
Resistance not clinically significant. Macrolide / tetracycline / respiratory FQ remain reliably active.
Resistance notes
Clinically meaningful resistance not described. β-lactams intrinsically inactive (no peptidoglycan).
Common syndromes
Pearls
Mild self-limited CAP in young adults, often with concurrent pharyngitis (more prominent than in Mycoplasma) and laryngitis. Longer incubation (3–4 weeks) than Mycoplasma. Often biphasic (URI prodrome → pneumonia 1–3 weeks later). Possible association with chronic conditions (atherosclerosis, asthma exacerbation) — controversial. Less severe than Mycoplasma; rarely requires hospitalization in healthy hosts.
References
- IDSA/ATS Community-Acquired Pneumonia in Adults (2019)