Infection mechanism of biofilm‐forming Staphylococcus aureus on indwelling foreign materials in mice

Abstract

Indwelling foreign-body infections are a critical medical problem, especially in immunocompromised patients. To examine the pathogenicity of biofilm-forming bacteria settling on foreign materials, mice implanted with plastic discs were infected with Staphylococcus aureus. After opening a wide subcutaneous pocket on the dorsal side of mice with or without temporal leukocytopenia, a plastic sheet was placed in the left subcutaneous space; subsequently, bacteria in a planktonic state were dispersed over the subcutaneous space. Bacterial numbers were examined 7 days after inoculation. In subcutaneous tissue on the right, S. aureus was found only in leukocytopenic mice. Meanwhile, bacteria were detected on the plastic and neighbouring tissue in both leukocytopenic and normal mice; however, colony-forming analysis indicated that leukocytopenic mice possessed significantly more bacteria. Tissue reaction against bacteria was pathologically examined. Invading S. aureus induced severe inflammation. In transient leukocytopenic mice, bacterial microcolonies formed on the plastic as well as in the developed necrotic tissue - both of which were shielded from inflammatory cell infiltration - result in bacteraemia. These results indicate that biofilm-forming S. aureus settling on indwelling foreign material are tolerant against host immunity and assault neighbouring tissue, which may lead to chronic wound infection.

Micellar curcumin improves the antibacterial activity of the alkylphosphocholines erufosine and miltefosine against pathogenicStaphyloccocus aureusstrains

“…Most of the classical antibiotics are designed to destroy fast-growing metabolically active bacteria in aerobic conditions, whereas biofilms consist of multiple layers of slow growing antibiotic tolerant microorganisms in a low metabolic state [56]. The pathogenic bacterial species S. aureus appears to possess a strong adhesion function and is well-known for its capability to form biofilms by attaching to substrate surfaces [69][70][71]. Current strategies to combat this medical problem include killing of the bacteria, mechanical removal of the biofilm or chemical degradation by chelating complexes and surfactants.…”

Biofilm-Forming Methicillin-Resistant Staphylococcus aureus Survive in Kupffer Cells and Exhibit High Virulence in Mice

“…OJ-1, a previously reported biofilm-forming isolate that had been collected from a wound surface [ 24 ], was used as the control. In a study based on differences in biofilm-forming ability, 20 clinical MRSA isolates from blood specimens were selected and classified as the low-biofilm formers (L-BF; 10 isolates) and high-biofilm formers (H-BF; 10 isolates) ( Table 1 ).…”

“…The relationship between the biofilm-forming ability of MRSA and its bacterial virulence remains entirely unknown. Our previous study of foreign body infections using mice has shown that biofilm was crucial for bacterial survival in vivo [ 24 ]. However, it has been reported that biofilm is not a required condition for foreign body infection [ 41 ].…”

“…The bacterial isolates were thawed from the stocks and were incubated on Tryptic Soy Agar (TSA) (Becton, Dickinson and Company, Franklin Lakes, NJ, USA) containing 0.5% NaCl. When colonies formed, one colony was collected and scattered in 5 mL of Tryptic Soy Broth (TSB) (Becton, Dickinson and Company) in 12 mL plastic test tubes with screw caps (SARSTEDT, Tokyo, Japan), and bacterial culture was carried out at 37 °C [ 24 ]. Those that achieved a stable growth were cultured on agar again, and colonies formed were stored at 4 °C and were used in experiments within one month.…”

PCR in Traumatology and Orthopaedics: Method Description and Applicability

“…Ввиду подобной устойчивости микробные биопленки имеют большую клиническую значимость как при лечении пациента в текущий момент времени, так и в отдаленной перспективе, особенно в случае эндопротезирования суставов, поскольку искусственные суставы -это одна из наиболее уязвимых групп имплантатов, для которой риск в отношении развития или рецидива инфекции сохраняется пожизненно. Поэтому современные исследования хирургических инфекций много внимания уделяют проблеме образования микробных биопленок непосредственно на тканях человека в области хирургического вмешательства и на изделиях медицинского назначения [24,39].…”