Species Spectrum of Bacterial Factors of Nosocomial Respiratory Infections in Hospitals of Lviv and the Prevalence of Antimicrobial Resistance Among Them

Abstract

Introduction. Healthcare-associated infections (HAIs) are a pressing problem in the health care system. Respiratory tract infections (RTI) are the second most common group of HAIs. One of the determining factors in the development of nosocomial pneumonia, which is predominantly bacterial in origin, is the properties and level of virulence of microbial factors. Early nosocomial pneumonia occurs when the upper respiratory tract microbiota infects the respiratory tract. Late nosocomial pneumonia is caused by nosocomial strains of microorganisms, characterized by multidrug resistance to antibiotics and disinfectants high levels of virulence, which include P. aeruginosa, Acinetobacter spp., Enterobacteriaceae family, MRSA. Unfortunately, in Ukraine, the structure and prevalence of HAIs and the antimicrobial resistance of pathogens are extremely poorly studied. The aim of the study. Therefore, the study investigates the species spectrum and antimicrobial resistance of the main causative agents of respiratory tract infections. Materials and methods. A study of microbial factors of nosocomial respiratory tract infections in 4 hospitals in Lviv. 205 patients of intensive care units diagnosed with RTI (36.6 %) were examined. Statistical analysis of the results was performed using the standard package of the program “Microsoft Excel 2010”. Microbiological diagnostics were performed following current regulations in the specialty “Bacteriology and Virology” and “Guidelines for Clinical Microbiology” of the 12th revision of the American Association for Microbiology. Microbiological diagnostics is performed in the research laboratory of the Department of Microbiology of Danylo Halytsky Lviv National Medical University. Results. The species profile of the detected pathogens of RTI indicates that among 14 representatives of different taxa, the gram-positive microbiota predominates, but the quantitative level of seeding per gram-negative microbiota accounts for 70.17 %. Among the isolates – factors of HAIs, multidrug-resistant (MDR) share accounted for 62.8 %. 3 strains are classified as pan drug resistant (PDR): 2 – P. putida and 1 – P. aeruginosa. Of the gram-positive microbiota, Enterococcus spp., represented mainly by E. faecalis and E. faecium, was most often detected in clinical material. E. faecalis was most often detected in the clinical material of the gram-positive microbiota. E. faecalis isolates were characterized by pronounced resistance to penicillins (including oxacillin), cephalosporins, fluoroquinolones, erythromycin and azithromycin, clindamycin with preserved sensitivity to vancomycin and linezolid. Pseudomonas aeruginosa isolates showed absolute sensitivity to colistin. Among other antibiotics, the most effective in terms of the number of sensitive strains were carbapenems – imipenem (57.5 %) and meronem (55.0 %). Only 37.5 % of the cultures were sensitive to tobramycin and tegicillin, an inhibitor of the protected cephalosporin antibiotic, sulfperazone. The genus Staphylococcus was among the causative agents of pneumonia other than Staph. aureus subsp. aureus, will Staph. haemolyticus, Staph. lugdunensis. Moreover, only one strain of methicillin-resistant Staphylococcus was detected. Most cases of RTI (57.4%) of patients in intensive care units occurred within 48 hours after the installation of a tracheostomy or intubation tube. Conclusions. According to the results of microbiological diagnostics, it has been established that the main etiological factors of nosocomial pneumonia associated with medical care are opportunistic microorganisms – Pseudomonas aeruginosa and enterococci. 62.8 % of strains were MDR. Furthermore, the results of monitoring the antibiotic resistance of hospital strains of microorganisms show their differences in different institutions of Lviv and the connection exclusively with the hospital environment. Therefore, optimization of antimicrobial treatment of nosocomial pneumonia is possible only based on the broader use of microbiological research results, constant monitoring of the microbiological status of patients in intensive care units, hospitality (distribution and properties of pathogens in hospitals).