Introduction:
Under natural conditions, airways are exposed to various microorganisms present in the environment. The development of an infection occurs through an imbalance between the defense capabilities and the virulence of microorganisms. Respiratory tract infections caused by bacteria lead to mild and severe inflammation of the airways. The group of microorganisms occurring as an etiological factor of bacterial respiratory infections, in addition to frequently occurring Gram (-) rod-shaped bacteria, includes Gram (+) microorganisms, among them: Streptococcus pneumoniae, Streptococcus pyogenes. In recent years, there has been an increase in the resistance of microorganisms, isolated from infections, to many antibiotics. Therefore, analysis of the pathogenic species Gram (+) as well as the profiles of their resistance during a period of 5 years became expedient.

Material and methods:
3810 results of bacteriological tests of sputum and bronchial lavage were evaluated, which were collected from patients hospitalized in the Department of Lung Diseases and Tuberculosis of the Independent Public Clinical Hospital No. 3 in Zabrze. The study was conducted in the Microbiological Laboratory of the Department of Microbiology and Immunology in Zabrze, Medical University of Silesia in Katowice.

Results:
1263 strains of pathogenic bacteria were cultured, including 445 strains of Gram (+) rod-shaped bacteria, which comprised 35.2% of the total amount of pathogenic bacteria. The predominant pathogen in Gram (+) bacteria over 5 years was S. aureus MSSA from sputum and bronchial lavage. Gram (+) microorganisms, in 2008–2012, showed the highest percentage of resistance in relation to tetracyclines, then to macrolides, sulfonamides, trimethoprim and lincosamides. The percentage of resistance in relation to quinolones and aminoglycosides was at a similar level. Emergency microorganisms Gram (+) showed the highest percentage of resistance over 5 years compared to macrolides and lincosamides.