Local microbiological monitoring as a basis for determining etiological significance of conditional pathogens: data from a burn intensive care unit

Objective. To assess the etiology of infections, microbial associations and antimicrobial resistance in a burn intensive care unit. Materials and Methods. A microbiological study of 1322 biological samples from 195 patients with extensive burns included 479 blood samples, 82 respiratory samples, 326 urine samples, and 435 wound samples. Antimicrobial susceptibility testing was performed, and coefficients of constancy and associativity (CA), as well as the Jaccard coefficient were calculated. Results. The etiology of infections was represented by: Pseudomonas aeruginosa – 23%, Acinetobacter baumannii – 19.1%, Enterococcus faecalis – 18.6%, Klebsiella pneumoniae – 8.2%, CoNS (coagulasenegative staphylococci) – 8.2%, Staphylococcus aureus – 7.1%, Candida albicans – 7.1%, Candida non-albicans – 3%, other species were isolated with a frequency of less than 2%. Majority of the above mentioned pathogens showed high associativity: non-fermenting rods (NFR), S. aureus, Enterobacterales, E. faecalis, Candida non-albicans formed associations in 60.0%, 88.8%, 83.0%, 83.3% and 65% of cases, respectively. The prevalence of methicillin-resistant strains of S. aureus and CoNS was 71% and 81%, respectively. CoNS showed higher resistance to fluoroquinolones and gentamicin compare to S. aureus: 42% vs 23%, 46% vs 29%, respectively (χ2 = 6.91; p = 0.086; χ2 = 6.58; p = 0.013). E. faecalis showed high resistance rates to aminoglycosides and fluoroquinolones (> 60%). All Gram-positive isolates were completely susceptible to vancomycin, linezolid, tigecycline, and teicoplanin. Resistance rates of Gram-negative bacteria (NFR, K. pneumoniae) to penicillins, cephalosporins, carbapenems (for NFR), and aminoglycosides were high (from 60% to 100%). The most active antimicrobial against NFR was colistin. Resistance of K. pneumoniae isolates to carbapenems was 23%, while other enterobacteria were highly susceptible to carbapenems. Conclusions. The implementation of the local microbiological monitoring made it possible to characterize the qualitative pathogen structure and antimicrobial resistance in our burns intensive care unit. This data will serve as the basis for improving of the infection control and antimicrobial stewardship.