4-8 CHLAMYDIA PNEUMONIAE AS A NEW SOURCE OF INFECTIOUS OUTBREAKS IN NURSING HOMES
Influenza virus and respiratory syncytial virus are well-recognized causes of respiratory infectious in elderly persons living in long-term care facilities.
Chlamydia pneumoniae (CP) accounts for about 10% of community-acquired pneumonias, again with the highest incidence among the elderly.
This study determined the extent and severity of illness and the mode of transmission of CP infection in nursing home outbreaks.
Conclusion: CP caused serious morbidity and mortality among residents and morbidity among staff.

STUDY

1. Retrospective cohort study of an outbreak of illness in 3 nursing homes in fall of 1994 entered over 500 residents and over 60 staff members.
2. The illnesses reported were characterized by abrupt onset of nonproductive cough with other symptoms including congestion, sore throat, fever, and hoarseness.
3. Extensive laboratory investigation had failed to identify the cause of the outbreak until paired serum samples showed antibody titers suggesting acute infection with CP.
4. Serologic testing was done for CP. Nasal swabs were tested by direct fluorescent antibody assays to confirm CP infection.

RESULTS

1. Attack rates with CP varied between 68% and 44% among residents, and were 34% among staff.
2. Sixteen cases of pneumonia were confirmed. There were 6 deaths.
3. The high attack rate, the occurrence of pneumonia, and the deaths demonstrated the substantial morbidity CP can cause in these settings.
4. Spread of the infection can be rapid. A number of studies support the role of person-to-person airborne transmission of CP.
5. Among the institutionalized elderly, a nonproductive cough may be the first recognized symptom.
6. CP is susceptible to tetracycline, erythromycin, and other macrolides in vitro. Both erythromycin and tetracycline were used in an uncontrolled manner in this outbreak. No conclusions were drawn about effectiveness.
7. "Residents who smoked had onset of illness earlier than nonsmokers which perhaps is related to airborne transmission in a designated smoking room."¹

CONCLUSION
CP can cause serious morbidity and mortality among residents and staff of nursing homes.
JAMA April 16, 1997; 277: 1214-18 Original investigation first author from Ontario Ministry of Health, Toronto, Canada

Comment:

1. This is the first reference to this concept I have encountered. Is there another downside to smoking now that smokers are segregated from non-smokers and may be confined together in a smaller space?
Important to recognize — C pneumoniae infection is treatable with tetracycline and erythromycin. RTJ

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