Taxonomic composition, population level, and microecological parameters of microbiota of purulent content of the tympanic cavity in patients with chronic purulent mesotympanitis

Abstract

Resume. To study the taxonomic composition, population level and microecological indices of the ecosystem "macroorganism-microbiota" of purulent contents of the tympanic cavity in patients with chronic purulent mesotympanitis.Materials and methods. The samples (ears discharge) taken from 78 patients (38-64 years old) with chronic purulent mesotympanitis were used in this study.A bacteriological examination of the selected samples was carried out by isolating and identifying microorganisms with the determination of their sensitivity to antibiotics. The bacteriological investigation included the study of morphological, tinctorial, cultural and biochemical properties of isolated cultures by conventional methods. Inocula from the ear canals of 27 healthy people aged 35-62 years were a control group.To reveal the mechanisms of colonization (contamination) by microorganisms of the tympanic cavity and external auditory canal in patients with chronic purulent mesotympanitis used ecological method, which allowed to determine the biological characteristics of associative groups of microorganisms and coexistence processes of different groups of microbiota. The features of the species diversity and richness of the microbiocenosis were characterized by the value of the Margalef’s and Whittaker’s indices.The level of taxon dominance in the biotope was determined by the value of the species dominance of Simpson’s and Bɟrger-Parker’s indices [11]. The quantitative predominance of the taxon and its role in the formation of the microbiocenosis of the biotope was determined by the value of quantitative dominance.Results. The results show that the persistence index, the frequency of occurrence of the taxon, as well as the index of the species richness of Margalef and the species diversity of Whittaker, as well as the indices of species dominance of Simpson and Berger-Parker there is common in the content of the tympanic cavity - S. aureus. There’re not often found in the biotope S. epidermidis, C. xerozis, S. haemolyticus, E. faecalis, P. aeroginoza, P. vulgaris, C. albicans, A. niger, which according to these indices are accidental. In the course and development of chronic purulent mesotympanitis there is a contamination and colonization of the tympanic cavity by conditionally pathogenic staphylococci (S. aureus, S. haemolyticus), enterococci (E. faecalis), enterobacteria (P. vulgaris), candida and aspergillus. The leading agents of the purulent-inflammatory process in 23 (29.49 %) patients are S. aureus, S. hemolyticus and E. faecalis - in 13 (16.67 %) patients, P. aeroginoza - in 10 (12.82 %) patients, in 7 (8.47 %) patients- P. vulgaris, in 4 (5.13 %) patients - S. epidermidis, in 3 (3.85 %) patients - C. albicans in one patient (1.28 %) inflammatory process was caused by A. niger. In 4 (5.13 %) patients from the contents of the tympanic cavity, opportunistic pathogens were not isolated.Conclusion. The purulent-inflammatory process in the middle ear of patients with chronic purulent mesotympanitis is a polyetiological disease caused by conditionally pathogenic bacteria and fungi (S .aureus, S. hemolyticus, S. epidermidis, E. faecalis, P. aeroginoza, P. vulgaris, C. albicans, A. niger). The leading agents of chronic purulent mesotympanitis are staphylococci (S. aureus, S. hemolyticus, S. epidermidis), enterococci, and pseudomonads. In most (94.87 %) of patients with purulent content, an association consisting of two microorganisms belonging to 12 different taxonomic groups persists. The microflora of the middle ear in patients with chronic purulent mesotympanitis is diverse in species composition, which must be considered for empiric antibacterial therapy.