Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila in elderly patients with stroke (C-PEPS, M-PEPS, L-PEPS): a case-control study on the infectious burden of atypical respiratory pathogens in elderly patients with acute cerebrovascular disease.

Abstract

Multiple studies have suggested an association between Chlamydia pneumoniae and Mycoplasma pneumoniae infection and cardiovascular disease. We investigated whether the risk of cerebrovascular disease is associated with Legionella pneumophila infection and the aggregate number/infectious burden of these atypical respiratory pathogens. One hundred patients aged >65 years admitted with acute stroke or transient ischemic attack (TIA) and 87 control patients admitted concurrently with acute noncardiopulmonary, noninfective conditions were recruited prospectively. Using enzyme-linked immunosorbent assay (ELISA) kits, we previously reported the seroprevalences of C pneumoniae and M pneumoniae in these patients. We have now determined the seroprevalences of L pneumophila IgG and IgM in this cohort of patients using ELISA. The seroprevalences of L pneumophila IgG and IgM were 29% (n=91) and 12% (n=81) in the stroke/TIA group and 22% (n=86) and 10% (n=72) in the controls, respectively. Using logistic regression to adjust for age, sex, hypertension, smoking, diabetes, ischemic heart disease, and ischemic ECG, the odds ratios for stroke/TIA in relation to L pneumophila IgG and IgM were 1.52 (95% CI, 0.70 to 3.28; P=0.29) and 1.49 (95% CI, 0.45 to 4.90; P=0.51), respectively. The odds ratios in relation to IgG seropositivity for 1, 2, or 3 atypical respiratory pathogens after adjustment were 3.89 (95% CI, 1.13 to 13.33), 2.00 (95% CI, 0.64 to 6.21), and 6.67 (95% CI, 1.22 to 37.04), respectively (P=0.06). L pneumophila seropositivity is not significantly associated with stroke/TIA. However, the risk of stroke/TIA appears to be associated with the aggregate number of chronic infectious burden of atypical respiratory pathogens such as C pneumoniae, M pneumoniae, and L pneumophila.