PURPOSE: Community acquired pneumonia is a very frequent disease. There are few studies comparing serological tests and cultivation methods in the detection of etiological agents in out patients with pneumonia.
METHODS: Nine centers took part in an observational study. Patients were enrolled according to the declared protocol based on PSI score (category I or II). Clinical symptoms, X-ray signs, axillary measured temperature, leukocytosis, sputum microscopy and cultivation, paired serology for M. pneumoniae and C. pneumoniae (respiratory viruses, L. pneumophila) and antibiotic effectiveness were statistically processed by multivariable analysis (ANOVA).
RESULTS: Series consisted of 130 patients, 58 men and 72 women, mean age 46.3 years. According to microbiological tests, the cause of pneumonia was a typical agent in 34.6%, an atypical agent in 30.8 % and mixed infection in 13.1%. The causative agent was not recognized in 21.5% cases. Gram-positive cocci were found in sputum in 36.2%. The most frequent pathogens found were C. pneumoniae (39.2%), H. influenzae (20.8%), M. pneumoniae (10.8%), S. pneumoniae (10.8%) and S. aureus (4.6%). The most frequent symptoms were cough (86.2%), weakness (61.5%), expectoration (50.8%), dyspnea (47.7%) and thoralgia (40.8%). Temperature was elevated in 97.7 %, leukocytosis in 39.2%. Statistically significant differences were recognized in leukocytosis (higher in typical agents), longer lasting cough and higher weakness frequency (in atypical agents) and thoracalgia (in mixed infections). The most frequent antibiotics used were macrolides (53.6%), penicilines (27.4%), cephalosporines (9.1%), quinolones (6.3%), tetracyclines (2.2%), cotrimoxazol (1.1%). Betalactams were used more frequently in pneumonia caused by typical pathogens. Second antibiotic had to be applied significantly more often in mixed infections.
CONCLUSION: Microbiological methods had limited value for the choice of the initial antibiotic treatment. Discrepancy between microscopy and cultivation of sputum was probably caused by high susceptibility of S.pneumoniae. Serological tests showed very frequent presentation of atypical pathogens, but the results cannot be interpreted without hesitation because of low specificity and anamnestic reactions.
CLINICAL IMPLICATIONS: The empirical treatment of mild pneumonia was successful and only two patients were sent to the hospital.
DISCLOSURE: Vitezslav Kolek, No Financial Disclosure Information; No Product/Research Disclosure Information