Ambulatory infections of the respiratory tract are among the commonest infections in the human. Depending on the season of the year and climate they make about 20-25% of all the reasons for attendance to the general practitioner. The most common bacterial cause of day care respiratory infections are: S. pneumoniae, H. Influenzae, M. Catarrhalis, S. pyogenes, more seldom S. aureus, and in older patients Klebsiella pneumoniae, Escherichia coli and anaerobic bacteria of Bacteroides, Fusobacterium, Peptococcus, and Peptostreptococcus genera. Due to difficulties in isolation of microorganisms and their cultivation, as well as troubles with distinguishing between colonization and infection, microbiological examination does not offer 100% possibility of eliciting the real etiologic factor. Microbiological diagnosis of ambulatory cases of bronchitis and pneumonia is based on examination of the patient's expectoration. All the etiologic factors causing acute lower respiratory infections, except for Mycobacterium tuberculosis and Legionella spp, occur in the physiologic flora of the upper respiratory tract. Therefore the mere isolation of these microorganisms does not necessary indicate their etiologic function in the particular case. The results of the drug-sensitivity tests may not have the same effects in the clinic. Infection is a complex process, which takes place between a microorganism and a host. Among the factors that influence the results of the treatment in the clinic are: location of the inflammation, antibiotic penetration into the infected area and acquisition of the drug therapeutic concentration, immunological and pharmacokinetic aspects of the antibiotic along with interactions between the natural and pathological bacterial flora. It is essential to distinguish between the lack of microbiological sensitivity of the organism and the lack of the clinical drug-efficacy. All these difficulties make the physician to start empirical treatment in day care bacterial respiratory infections. Cefaclor is an oral antibiotic indicated in the ambulatory treatment of those infections that do not threat the patient's life. Its spectrum of activity ideally suits the frequency of etiological agents currently occurring in respiratory infections. It is a drug of basic significance in empirical therapy when the immediate comparison with the results of the drug resistance test is not possible. Because it rarely causes complications, Cefaclor may be indicated in ambulatory treatment of respiratory infections in children. In such cases this antibiotic should replace previously prescribed and applied drugs which do not express activity against b-lactamase-positive bacterial strains and evoke unwanted effects more often than cefaclor.

Keywords: Cefaclor, Respiratory Tract Infections, antibiotherapy