Effect of sub-inhibitory concentrations of biocides on the architecture and viability of MRSA biofilms

• Laura Buzón-Durán ^[1] ; Carlos Alonso-Calleja ^[1] ; Félix Riesco-Peláez ^[1] ; Rosa Capita ^[1]
  1. [1] Universidad de León

     Universidad de León

     León, España

     
• Localización: Food microbiology, ISSN 0740-0020, Vol. 65 (August), 2017, págs. 294-301
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • The effect of sub-minimum inhibitory concentrations (sub-MICs) of three biocides (benzalkonium chloride [BZK], trisodium phosphate [TSP] and sodium hypochlorite [SHY]) upon the architecture and viability of the biofilms formed by a methicillin-resistant Staphylococcus aureus strain of food origin (MRSA 48a) was investigated. Images were examined through confocal laser scanning microscopy (CLSM) after staining with SYTO9 and propidium iodide. Sub-MICs of BZK or TSP reduced the ability of MRSA to produce biofilm. In contrast, the presence of sub-MICs of SHY enhanced the biofilm-forming ability of MRSA when cells had undergone previous adaptation to this compound (biovolume in the observation field was 137,785.31 ± 47,682.79 μm3 for biofilms formed in the presence of SHY, and 70,204.13 ± 31,603.98 μm3 in the absence of biocides; P < 0.05). The largest amount of live (green stained) cells (P < 0.05) was observed in biofilms grown in the presence of SHY relative to the other conditions tested (58,999.75 ± 55,312.37 μm3vs 31,976.29 ± 38,594.98 μm3). Findings from the present work constitute the first report of biofilm production by MRSA being induced by sub-inhibitory concentrations of SHY. The data suggest that repeated use of SHY at low concentrations could represent a public health risk.