Influence of microbiological characteristics of infections caused by Klebsiella pneumoniae on antibiotic resistance and severity of the infection process

The aim of the study was to investigate influence of microbiological characteristics of infections caused by Klebsiella pneumonia on formation of antibiotic resistance and severity of infectious process. Material and methods. A comparative analysis of biofilm mass, thickness of capsule of K. pneumonia isolated from 26 patients with sepsis and from 8 patients with chronic obstructive pulmonary disease was carried out. The influence of capsule thickness on severity of infectious process and antibiotic resistance was studied. Results and discussion. The mass of K. pneumoniae biofilm isolated from patients with sepsis was 28.2 [16.5; 41.3] μg/well (median [lower quartile; upper quartile]), exhibited resistance to most of the antibacterial drugs used, and was greater than the biofilm mass isolated from patients with chronic obstructive pulmonary disease (24.3 [20.0; 28.2] μg/well, p = 0.04), which remained susceptible to the drugs used. K. pneumoniae bacterial capsule was identified as a species characteristic or pathogenicity property using developed method with alcian blue. Panresistant K. pneumoniae isolates had the thickest capsule (0,44 [0,32; 0,53] μm), carbapenem-resistant isolates sensitive to colistin and tigecycline had thinner capsule (0.38; 0.35–0.41 μm). Thickness of capsule of Klebsiella that retained sensitivity to carbapenems was 4 and 3.5 times thinner than thickness of panresistant ( p = 0,031) and carbapenem-resistant isolates sensitive to colistin and tigecycline isolates ( p = 0,044), respectively and was 0,11 [0,08; 0,16 мкм]. A positive correlation was revealed between thickness of capsule, mass of microbial biofilm and length of hospital stay. Conclusions. The pathogenicity of bacteria and severity of disease are explained by thickness of K. pneumoniae capsule that makes a certain contribution to formation of antibiotic resistance in microorganisms.