Background
Mycoplasma pneumoniae is one of the most common causes of community-acquired pneumonia (CAP). This infection occurs predominantly in school-aged children and younger adults, but may also occur in the elderly.
Material and Method
To investigate the frequency and clinical characteristics of M. pneumoniae pneumonia in the elderly, we analyzed 210 hospitalized patients with M. pneumoniae pneumonia over a 15-year period.
Results
Thirty-two (15.2%) were 60 years of age or older. The frequencies of a comorbid illness with the age >or=60-years group were significantly higher than those of the age <60-years group (p<0.0001). The symptoms were almost identical in both age groups, but the fever magnitude was significantly lower in the age >or=60-years group than the age <60-years group (p<0.0001). One or more additional etiological factors were found more frequently in the age >or=60-years group than in the age <60-years group (37.5% vs 10.1%, p=0.0003). The diagnostic sensitivity for M. pneumoniae pneumonia using the Japanese CAP guidelines scoring system was significantly lower in the age >or=60-years group than in the age <60-years group (50% vs 90%, p <0.0001).
Conclusions
Our results indicate that the frequency of M. pneumoniae pneumonia in the elderly was low but not rare. The symptoms and severity of the illness from this infection were almost identical in both age groups and the mortality rate was low even in the elderly. It seems to be difficult to distinguish between M. pneumoniae pneumonia and bacterial pneumonia in the elderly.

Keywords: Pneumonia, Mycoplasma - microbiology, Japan - epidemiology, Mycoplasma pneumoniae - physiology, Community-Acquired Infections - microbiology, Age Distribution