Effect of selected disinfectants on biofilm-forming clinical isolates of Staphylococcus aureus in Lagos State, Nigeria

Abstract

Background and Aims: Staphylococcus aureus is one of the most important pathogens of public health concern and a leading cause of nosocomial infections. In this study, we evaluated the effect of routinely used disinfectants in hospitals for surface decontamination on biofilm-forming S. aureus. Materials and Methods: forty-eight S. aureus isolates were phenotypically evaluated for biofilm formation using the Tissue Culture Plate (TCP) technique. Effect of disinfectants (Dettol®, Izal®, Jik® and Savlon®) on biofilm was tested and time-kill kinetics evaluated. PCR was used to confirm the identity of S. aureus using species-specific primers. Results: biofilm formation assay revealed that 15 (31.2%) of the isolates formed biofilm with 7 (14.5%) and 8 (16.6%) considered as strong and moderate biofilm formers, respectively. Biofilm formation was time-dependent (p<0.0001). Jik® was significantly effective (p<0.0001) as it disrupted biofilm formed in all 15 (100%) isolates, followed by Izal® 13 (86.6%), Savlon® 11 (73.3%) and Dettol® 9 (60%). Time-kill kinetics of the four disinfectants revealed Dettol®, Jik® and Savlon® achieved total (100%), (7 log10) lethality against isolates within 1 h contact time while Izal® attained complete lethality at 6 h contact time. Conclusions: of the four disinfectants evaluated Jik®, a chlorine- based formulation, was more effective in destroying biofilmforming S. aureus. The need to use effective disinfectants in sanitization is imperative to facilitate the control and prevention of hospital and community-acquired infections.

Keywords

• Biofilm
• chlorine
• disinfectants
• Staphylococcus aureus