Transcriptomic Adjustments of Staphylococcus aureus COL (MRSA) Forming Biofilms Under Acidic and Alkaline Conditions

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) strains are important human pathogens and a significant health hazard for hospitals and the food industry. They are resistant to β-lactam antibiotics including methicillin and extremely difficult to treat. In this study, we show that the Staphylococcus aureus COL (MRSA) strain, with a known complete genome, can easily survive and grow under acidic and alkaline conditions (pH5 and pH9, respectively), both planktonically and as a biofilm. A microarray-based analysis of both planktonic and biofilm cells was performed under acidic and alkaline conditions showing that several genes are up- or down-regulated under different environmental conditions and growth modes. These genes were coding for transcription regulators, ion transporters, cell wall biosynthetic enzymes, autolytic enzymes, adhesion proteins and antibiotic resistance factors, most of which are associated with biofilm formation. These results will facilitate a better understanding of the physiological adjustments occurring in biofilm-associated S. aureus COL cells growing in acidic or alkaline environments, which will enable the development of new efficient treatment or disinfection strategies.

Confocal spectral microscopy, a non-destructive approach to follow contamination and biofilm formation of mCherry Staphylococcus aureus on solid surfaces

“…S. aureus can colonize the inanimate surfaces by forming biofilms in suitable growth conditions in hygienically sensitive places, such as hospitals and the food industry 36 . Biofilms are difficult to clean and can protect the bacterium from disinfectants 37 .…”

“…Biofilms are difficult to clean and can protect the bacterium from disinfectants 37 . Moreover, they do not only increase the chances of microbial survival but also pose a continuous risk of cross-contamination 36 . Therefore, studying the biofilm-forming ability and its characteristics is important to understand the bacterial hygienic risk on surfaces used for food preparation, packaging, cooking, and furniture in hospital or other indoor facilities.…”

Genomic comparisons and phylogenetic analysis of mastitis-related staphylococci with a focus on adhesion, biofilm, and related regulatory genes

“…The atl gene has also been implicated in adherence to fibronectin, heparin, and gelatin 19 which could confer an advantage during infection as heparin is released by mast cells and basophils at the site upon tissue damage 20 . The same could be noted about the pls gene, which encodes the plasmin-sensitive protein that has a role in adherence and is an important virulence factor in mouse septic arthritis model 4 . To date, and atl genes have not been well studied–even in recent genomic comparison studies of S. aureus isolates from bovine mastitis 21 , 22 .…”

“…In Staphylococcus spp., factors such as the fibronectin-binding proteins ( fnbA and fnbB ), elastin binding proteins ( ebpS ), clumping factors ( clfA and clfB ), and collagen-binding protein ( cna ) play important roles in binding to host cells, colonization, and invasion 2 . The pls gene, which encodes the plasmin-sensitive protein, also has an important role in bacterial adherence 4 . The surface proteins encoded by sasH and sasF , play a significant role in virulence because they bind to host extracellular matrix and plasma components.…”

Genome Comparison and Phylogenetic Analysis of Mastitis-Related Staphylococci with a Focus on Adhesion, Biofilm, and Regulatory-Related Genes

“…The autolytic protein (alt) degrades the peptidoglycan cell wall layer and plays a key role in bacterial cell wall metabolism 4 . Furthermore, the pls gene encodes the plasmin-sensitive protein that also has a role in bacterial adherence 5 . The surface proteins encoded by sasH and sasF, play an import role in virulence because they can bind to host extracellular matrix and plasma components, and only recently, they have been reported as prevalent adhesins in a genome comparison study of Staphylococcus spp.…”