Differential effects of planktonic and biofilm MRSA on human fibroblasts

Abstract

Bacteria colonizing chronic wounds often exist as biofilms, yet their role in chronic wound pathogenesis remains unclear. Staphylococcus aureus biofilms induce apoptosis in dermal keratinocytes, and given that chronic wound biofilms also colonize dermal tissue, it is important to investigate the effects of bacterial biofilms on dermal fibroblasts. The effects of a predominant wound pathogen, methicillin-resistant S. aureus, on normal, human, dermal fibroblasts were examined in vitro. Cell culture medium was conditioned with equivalent numbers of either planktonic or biofilm methicillin-resistant S. aureus, and then fed to fibroblast cultures. Fibroblast response was evaluated using scratch, viability, and apoptosis assays. The results suggested that fibroblasts experience the same fate when exposed to the soluble products of either planktonic or biofilm methicillin-resistant S. aureus, namely limited migration followed by death. Enzyme-linked immunosorbent assays demonstrated that fibroblast production of cytokines, growth factors, and proteases were differentially affected by planktonic and biofilm-conditioned medium. Planktonic-conditioned medium induced more interleukin-6, interleukin-8, vascular endothelial growth factor, transforming growth factor-β1, heparin-bound epidermal growth factor, matrix metalloproteinase-1, and metalloproteinase-3 production in fibroblasts than the biofilm-conditioned medium. Biofilm-conditioned medium induced more tumor-necrosis factor-α production in fibroblasts compared to planktonic-conditioned medium, and suppressed metalloproteinase-3 production compared to controls.

Hyperosmotic Agents and Antibiotics Affect Dissolved Oxygen and pH Concentration Gradients in Staphylococcus aureus Biofilms

“…Biofilms protect bacteria from opsonization, antibiotic exposure, and phagocytosis (4)(5)(6). Staphylococcus aureus, a common human pathogen, is often associated with biofilm infections (7)(8)(9) in chronic wounds (8,10,11). Such infections are problematic to treat because of the slow penetration of antimicrobials and antibiotics through the biofilm matrix (10,(12)(13)(14) and the formation of persister cells (15).…”

Stimulation of bacterial biofilms on Th17 immune cells

“…Some studies have shown that bacterial biofilms induce an increase of IL-6 and IL-8 (Eberhard et al, 2009;Cantero et al, 2013a,b). Some studies have reported that planktonic bacteria cause the body to produce more IL-6, IL-8, vascular endothelial growth factor, and transforming growth factor beta 1 compared with biofilm bacteria, while biofilm bacteria induce more tumor necrosis factor alpha (Kirker et al, 2012).…”

Determination of Antimicrobial Potentials of Ethanol Extract of <i>Combretum dolichopentalum</i> Leaves by Total Dehydrogenase Activity Assay

“…A study by Kirker et al [9] showed that wound healing can be accelerated in the presence of non-viable S. aureus as a result of the contribution by its cell wall and cell wall peptidoglycan components, which enhances number and alteration in location of phagocytes, increased proliferation of mesenchymal cells (notably fibroblasts), and increased angiogenesis and reparative collagen accumulation, as well as increasing the overall acute inflammatory response to injury [9].…”

“…Risk factors include poor sanitation and poor hygiene [9]. Escherichia coli are a gram-negative, facultative anaerobe [11], with most strain harmless, but some serotypes can cause serious food poisoning in their hosts.…”

“…Salmonella typhi is the causative agent of typhoid fever [9], a public health concern in communities where adequate treatment of water supplies including proper sewage disposal system is lacking [10]. Risk factors include poor sanitation and poor hygiene [9].…”