DIAGNOSIS OF BRONCHOPULMONARY INFECTIONS BY QUANTIFICATION OF MICROFLORA

The quantification of bacteria and fungi in sputum or bronchoaspirate is of clinical value for the diagnosis of respiratory tract infections . We have developed an easy method to count the micro-organisms in pat ients with respiratory tract infections. This consists of the quantifi cation of micro-organisms by subsequent streakings of a calibrated loo p on agar. The correlation between microbiological quantitative data a nd the clinical status of patients with lower respiratory tract infect ions is discussed. The data seem to indicate that certain bacteria pre sent in sputum or bronchoaspirate above a certain concentration may be responsible for lower respiratory tract infections. In patients with immunological disorders or chronic pathologies even lower concentratio ns of micro-organisms in bronchial secretions probably are enough to c ause infections. The advantage of this counting method of the microbic species from the respiratory tract consists of their quantification: thus we can attribute an etiological role to a high concentration of t he germs, while micro-organisms at low concentrations are probably con taminants. By this method isolated colonies are obtained after 12-18 h ours. The bacterial quantification, by respiratory samples examination of the same patient in the following days, allows us to evaluate the efficacy of antibacterial therapy, producing a reduction of bacterial concentration.