Background: Mycoplasma pneumoniae pneumonia is regarded as a community-acquired pneumonia, rarely requiring hospitalization, with sporadic cases or limited outbreaks occurring after close contacts with an infected patient. Few reports mention M pneumoniae pneumonia acquired during hospitalization.
Patients and methods: M pneumoniae was diagnosed in patients who developed pneumonia following perioperative and postoperative assisted ventilation by the isolation of M pneumoniae from bronchial washing, the detection of M pneumoniae DNA from bronchial washing, and serologic testing for the presence of specific immunoglobulin M (IgM) antibodies.
Results: Four patients were diagnosed as having M pneumoniae pneumonia following mechanical ventilation over a 1 1/2-year period. They were men, older than 50 years, and were hospitalized for vascular surgery. They developed febrile hypoxemia and intersticial pneumonia. Isolation of M pneumoniae and detection of M pneumoniae DNA were positive in 1 case; specific IgM antibodies were present in 4 cases.
Conclusions: These observations allow the description of a new clinical entity and highlight the role of M pneumoniae as an agent of nosocomial infections. This diagnosis should be considered in any patient with precocious post-assisted ventilation febrile hypoxemia and diffuse interstitial pneumonia, and empiric treatment protocols may include M pneumoniae in their spectrum.