Oral cavity represents an ideal environment for the microbial cell growth, persistence, and dental plaque establishment. The presence of different microniches leads to the occurrence of different biofilm communities, formed on teeth surface, above gingival crevice or at subgingival level, on tongue, mucosa and dental prosthetics too. The healthy state is regulated by host immune system and interactions between microbial community members, maintaining the predominance of “good” microorganisms. When the complexity and volume of biofilms from the gingival crevice increase, chronic pathological conditions such as gingivitis and periodontitis can occur, predisposing to a wide range of complications. Bacteria growing in biofilms exhibit a different behavior compared with their counterpart, respectively planktonic or free cells. There have been described numerous mechanisms of differences in antibiotic susceptibility of biofilm embedded cells. Resistance to antibiotics, mediated by genetic factors or, phenotypical, due to biofilm formation, called also tolerance, is the most important cause of therapy failure of biofilm-associated infections, including periodontitis; the mechanisms of tolerance are different, the metabolic low rate and cell’s dormancy being the major ones. The recent progress in science and technology has made possible a wide range of novel approaches and advanced therapies, aiming the efficient management of periodontal disease.
Part of the book: Periodontitis
Methicillin-resistant Staphylococcus aureus (MRSA) strains are known for their emergent multi-drug resistance phenotypes, implication in nosocomial infections and outbreaks worldwide, being commonly associated with hospital-acquired MRSA (HA-MRSA) and community-acquired MRSA (CA-MRSA) skin and soft tissue infections. S. aureus causes a wide spectrum of clinical symptoms, ranging from mild to life-threatening diseases; disease severity is determined by microorganism-related virulence factors and host condition. The ability of these strains to form microbial biofilms, one of the main pathogenicity factors, generates difficult medical problems, favored by the widespread use of large invasive medical procedures (probes, catheters, heart valves, prostheses). Contamination of these devices is associated with the risk of subsequent development of human infections. The knowledge of virulence and antibiotic resistance patterns of HA-MRSA and CA-MRSA and encoding genes are very important for supporting effective infection control measures and therapy of staphylococcal infections.
Part of the book: Staphylococcus Aureus