Venzheha O, Bahrova A, Priyan I, Lavrentieva K, Sklyar T.

Oles Honchar Dnipro National University


Nosocomial infections are a global medical, social, and economic problem. The most important role in their occurrence, according to world statistics, belongs to the species Pseudomonas aeruginosa and Staphylococcus aureus. Recently, there have been increasing reports of appearance of cross-resistance to antibacterial preparations among pathogens: multiple antibiotic resistance due to adaptation to disinfectants.

The aim of the study was to assess the level of resistance to disinfectants of biofilm-forming and nonbiofilm-forming clinical strains of P. aeruginosa and S. aureus – the causative agents of nosocomial infections.

Samples of detachable wounds of patients with nosocomial infections were taken in accordance with the guidelines for compliance with the sanitary-epidemiological regime in health care facilities of Ukraine. The ability to form biofilms was detected by using a modified method (O’Toole et al., 2000). The sensitivity of isolated strains – pathogens of nosocomial infections to disinfectants (0.1 and 0.2% solutions of «Desactin», 0.03 and 0.1% solutions of «Neochlor tabs») was determined by the method of batiste test objects.

Among the clinical samples, 43 strains of S. aureus were isolated, of which 72.1% had the biofilm-forming ability, and 39 strains of P. aeruginosa, of which 61.5% were biofilm-forming. Of the two types of chlorine-containing disinfectants, «Desactin» was the most effective against all isolates of S. aureus. In 90.3% of cases, the tested solutions of both concentrations of «Desactin» inhibited the growth of biofilm-forming isolates of S. aureus. All 12 nonbiofilm-forming variants of S. aureus were sensitive to this disinfectant. «Neochlor tabs» proved to be a less effective disinfectant. The number of susceptible strains of S.aureus, not capable of biofilm formation, was less than 75.0% and in the case of biofilm-forming isolates – even less (61.3%). For P. aeruginosa strains, in 100% of cases, the growth of nonbiofilm-forming isolates was inhibited by «Desactin» (0.1 or 0.2% solution). The same effect was observed using 0.1% solution of «Neochlor tabs». Biofilm-forming strains of P. aeruginosa had a higher degree of resistance to the action of both types of disinfectants: bactericidal effect of 0.1% solution of «Neochlor tabs» was observed in 75.0%, and solutions of «Desactin» – in 62.5% of cases.

According to the results of determining the effectiveness of chlorine-containing disinfectants «Dezactin» and «Neochlor tabs» against isolated agents of nosocomial infections, the strains of S. aureus and P. aeruginosa, capable of biofilm formation, were found to be characterized by a higher degree of resistance to both types of disinfectants. The most effective disinfectant against isolated clinical nonbiofilm-forming strains of S. aureus and P. aeruginosa was «Desactin» in concentration of 0.1% or 0.2%. For S. aureus isolates capable of biofilm formation, its efficiency decreased by 9.7%. The best bactericidal effect against biofilm-forming strains of P. aeruginosa showed 0.1% solution of «Neochlor tabs». It inhibited the growth of 75.0% of the tested cultures.