Epidemiological survey on frequency of involvement of atypical pathogens in respiratory infections in outpatients

Yoichi Hirakata, Akira Watanabe, Yoshihito Niki, Nobuki Aoki, Shigeru Kohno

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    The frequency of the involvement of atypical microorganisms (Chlamydophila pneumoniae, Chlamydophila psittaci, Mycoplasma pneumoniae, and Legionella pneumophila) at the initial consultation for respiratory infections (pneumonia, bronchitis, pharyngolaryngitis and tonsillitis) was investigated by determining the serum antibody titers and urinary antigen levels of patients. The subjects were the outpatients aged 20 years or over who had made an initial consultation for a respiratory infection. Five hundred thirty-two patients who visited 59 practitioner offices in 4 districts of Japan (Nagasaki, Okayama, Niigata, and Sendai) between April 2003 and June 2003 were analyzed. Atypical microorganism were present in 99 patients (19%). The rates of positivity for each microorganism were 15% for C. pneumoniae, 4% for C. psittaci, 2% for M. pueumoniae and 0% for L. pneumophila. None of the patients tested positive for the urinary antigen of L. pneumophila. The rates of positive patients with atypical microorganisms according to disease were 19% for pneumonia, 20% for bronchitis, 19% for pharyngolaryngitis and 22% for tonsillitis; the rate was 11% for patients with two of these diseases. No tendency was observed with regard to the age distribution. The rate of C. psittaci positivity (4%) was higher than in previous reports, but no definite tendencies for age or geographic area were seen. Only two of the 21 positive patients were bird breeders. One in five patients with respiratory infections who visited a clinical practitioner's office tested positive for atypical microorganisms. Treatment drugs with good cell penetration and that cover atypical microorganisms should be selected for the treatment of respiratory infections.

    Original languageEnglish
    Pages (from-to)25-30
    Number of pages6
    JournalJapanese Journal of Chemotherapy
    Issue number1
    Publication statusPublished - 2006 Jan 1


    • Atypical pathogen
    • Epidemiological study
    • Respiratory infection

    ASJC Scopus subject areas

    • Pharmacology
    • Pharmacology (medical)


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