Ana Paula Dias Ribeiro - Faculdade de Odontologia - Unesp

infection, parotitis and staphylococcal mucositis [2]. There is also scientific evidencethat the oral cavity can be the source of the staphylococci responsible for infection atdistant sites, such as aspiration pneumonia, endocarditis, acute septic arthritis andchronic lung diseases [3].As the oral cavity can be an important reservoir of this opportunistic pathogen,much effort has been made in order to promote the decolonization of Staphylococcuscarriers [4]. However, the strategies to eliminate the S. aureus strains have beenchallenged with the development of antibiotic-resistant microorganisms, such as themethicillin-resistant S. aureus (MRSA). Strains of MRSA were first detected in 1961and these pathogens are currently prevalent worldwide [5]. MRSA has become amajor problem in nososcomial infections as it is responsible for significantly highermorbidity and mortality and increased healthcare costs [6]. It is known that thecolonization precedes the systemic infection and therefore decolonization may reducethe risk of MRSA infection in individual carriers and prevent cross-infection to otherpatients or healthcare workers. Intranasal mupirocin, daily chlorhexidine body wash,antibiotics such as rifampin and doxycline, oral hygiene procedures, use of denturecleansingagents and denture sterilization methods have been proposed to preventcolonization by MRSA and methicillin-susceptible S. aureus (MSSA) [6,7]. However,a systematic review concluded that there is insufficient evidence to support the use ofany topical or systemic antimicrobial therapy for eradicating MRSA [8].The photodynamic therapy (PDT) has emerged in the clinical field as apotential alternative to antibiotics for inactivating resistant microorganisms using anon-toxic light-sensitive compound (known as photosensitizer - PS), visible light andoxygen. Briefly, activation of the PS by a visible light that matches its photophysicalproperties generates reactive oxygen species (ROS) like free radicals by electron orhydrogen transfer (type I reaction) or reactive singlet oxygen by direct energy transferto oxygen (type II reaction) [9]. Photodynamic inactivation of microorganisms hasadvantages, such as the local application of PS and light, which limits the action ofROS and avoids systemic effects on normal bacterial flora [10]. In addition, unlikeantibiotics, which have a single target in the microbial cell, the reactive speciesgenerated by the photodynamic reaction have a multifunctional nature and candamage multiple cellular structures, reducing the chances of development of PDTresistantstrains [11]. Dovigo et al. [12] observed that fluconazole-resistant C. albicansand C. glabrata strains were sensitivity to PDT, although they were less susceptible