Biofilm formation of clinical isolates of opportunistic microorganisms under the influence of disinfectants

Objective.

To assess the ability of clinical isolates of opportunistic microorganisms to accumulate biofilm biomass under the influence of composite disinfectants.

Materials and Methods.

The study included 53 strains (49 – K. pneumoniae, 4 – P. aeruginosa) obtained from two multidisciplinary children’s hospitals at the city and regional levels. Specimens were collected from different loci of patients, medical devices, and environmental objects. To assess the reaction of biofilms (BF) of clinical isolates to the effects of disinfectants (DIs), three composite DIs were used: No. 1 – oxygen-containing, No. 2 – containing quaternary ammonium compounds and aldehydes, No. 3 – chlorine-containing.

Results.

All the studied strains were characterized by their ability to accumulate BF biomass of various degree: low – 15 (28.4%), moderate – 24 (45.2%), and high – 14 (26.4%). When exposed to DIs at the initial stage of adhesion, biomass of BF decreased in more than 70% of isolates, with chlorine-containing DI showing the greatest efficiency (No. 3). 24-hour BFs were resistant to the effects of DI No. 1 and DI No. 3; accumulation of BF biomass decreased only when using DI No. 2, which contained a complex of quaternary ammonium compounds and aldehydes. Isolates that initially had an increased ability to accumulate BF biomass were more resistant to the DIs effects at all stages of biofilm formation.

Conclusions.

There is a need for further in-depth evaluation of the biocides effects on biofilm bacteria to prevent healthcare-associated infections.