Effect of Disinfectants on Surface Hydrophobicity and Motility of Salmonella entericaserovar Typhimurium DT104

Overview

The paper evaluated antibacterial efficacy of 12 disinfectants on the basis of quaternary ammoniumcompounds (KAZ) on the isolates of Salmonella enterica serovar Typhimurium of the definitive phagetype 104 (DT104). One isolate – 5551/99 – represented the multiresistant phenotype, resistant toampicillin (A), chloramphenicol (C), streptomycin (S), and tetracycline (T). The second isolate –577/99 – was sensitive to all antibiotics tested. The present study further examined the capabilityof sub-MIC concentrations of disinfectants to intervene into surface hydrophobicity and motility ofthe strains tested.The results showed that all disinfectants under study exhibited high antibacterialactivity. It is of interest that the isolate resistant to antibiotics was more sensitive to disinfectantsin comparison with the isolate resistant to antibiotics. The most effective substances against strain5551/99 (R-type) were Sokrena, Triquart,Hexaquart plus, ID213,and Microbac forte,and those mosteffective against strain 577/99 (S-type) were Benzalkonium chloride and Hexaquart plus (MIC0.09–0,19 µl/ml). Surface hydrophobicity of both tested strains after the action of sub-MIC (1/16, 1/8,1/4 of MIC) of disinfectants was not influenced in a more marked way. In the case of strain 5551/99,the highest percentage of inhibition of adherence to xylene, to 69.5 % versus the control, wasproduced by 1/4 of MIC of the substance Triquart and, in the whole concentration range, by the substance Microbac forte. After the action of most substances to strain 577/99, stimulation ofadherence took place. Only substance ID213 induced inhibition of adherence in the whole concentrationrange.The salt-aggregative capabilities of both strainswere not influenced in amoremarkedway. The only exceptions were the action of 1/4 of MIC of the substances Cetrimid, Sokrena, ID212,Forten, and 1/8 of MIC of Hexaquart S on strain 577/99, where a decrease in hydrophobicity wasobserved.Amoderate inhibition ofmotilitywas found after the action of 1/4 of MIC of Benzalkoniumchloride (to 87.5 %) and A.D.L. 007 (to 85.2 %) on strain 5551/99. In the case of sensitive isolate577/99, the most markedly manifested inhibition effect was that of Sokrena within the wholeconcentration range and that of 1/4 of MIC ID213. The results can be used in the selection ofa suitable disinfectant for decontamination of solid surfaces. The effect of substances under studyon surface hydrophobicity and motility of the important, food-transferred pathogen in the sense ofinhibition or stimulation points out to intervention into its pathogenic potential.

Key words:
Salmonella enterica serovar Typhimurium DT104 – antibiotics – disinfectants –hydrophobicity – motility