Microecology of pyodermia pathogens

Abstract

Gram-positive cocci are usually considered the leading pathogens of pyoderma. However, understanding intermicrobial interactions, as well as identifying the leading pathogens and their associates, require a more detailed study of microbial contamination of the skin other than a simple statement of the taxonomic composition of the microbial community of the biofilm. The aim of this study is to determine the microecological indicators of pyoderma pathogens.

Material and methods. 97 patients with pyoderma were examined, material was taken during dressing and bacteriological examination was carried out no later than 2 hours later. A number of microecological indices were calculated (constancy index, Margalef species richness index, Whittaker species diversity index, Simpson and Berger-Parker species dominance indices, statistical processing – by the method of variation statistics.

Results. In total, 197 strains of conditionally pathogenic Gram-positive (89.85%) and Gram-negative (20-10.15%) bacteria were isolated and identified in the cohort of patients. Coagulase-positive S. aureus was the main one in the microbial group according to the constancy index, frequency of occurrence, Margalef species richness index, Simpson species diversity index and Berger-Parker species dominance. In 94 (96.91%) patients, associations consisting of two different taxa were detected, and in 3 (3.09%) associations consisting of 3 conditionally pathogenic taxa.

Conclusions. Pyodermas are polyetiological diseases caused by both Gram-positive and Gram-negative, facultative anaerobic and aerobic bacteria with a significant predominance of Gram-positive cocci, which are in association with other conditionally pathogenic microorganisms. According to the taxonomic composition and microecological indicators, the leading pathogens of pyodermas are S. aureus, P. aeruginosa, S. pyogenes and P. vulgaris, E. coli, E. coli Hly+ and E. Aerogenes.