Oral Carriage of Staphylococcus aureus among Dental Patients in Dependence on Conditions in Oral Cavity

Abstract

Introduction and aim: Staphylococcus aureus is a significant opportunistic pathogen possessing highly variable genome, causing thus wide range of infections. An important location where this pathogen may occur in healthy individuals includes not only organs such as skin, pharynx, nasal mucosa, etc., but also oral cavity. The main objective of our study was to find out whether various oral cavity conditions such as periodontitis, fixed and removable dental prostheses and stomatological diseases with indications for extraction influence the level of oral cavity colonization by the Staphylococcus aureus, as well as to define the frequency of occurence of methicillin-resistant strains of this microorganism in stomatological patients. Methods: The examined collection consisted of 96 patients, who attended dental services LUXDENT, Ltd., in Nitra from June 2014 to January 2015. Patients were divided into the groups studied, i.e., the group of patients with 1. periodontitis, 2. dental diseases with indications for extraction, 3. fixed or removable prosthetic restorations and 4. control group. Microbiological samples were obtained by sterile swabs from oral and nasal cavity of subjects included into study and delivered to the laboratory within 24 h. At the laboratory, samples were processed by standard methods for isolation and identification of Staphylococcus aureus and confirmed by polymerase chain reaction, in which the specific region of nuc gene, characteristic for Staphylococcus aureus was amplified. Methicillin-resistant strains of Staphylococcus aureus were identified using disc difusion method according to the methodology of the European Committee on Antimicrobial Susceptibility Testing [8]. Results: The presence of S. aureus was found in 35 samples (20.2%) out of 173 examined samples (oral and nasal cavity swabs), while 31 of those samples were methicillin-sensitive (88.58%) and four of them were methicillin-resistant (11.42%). There was a statistically important difference between the occurrence of the microorganism in nose and mouth (p < 0,05) indicating a more frequent occurrence in the nasal cavity. The presence of the microorganism in both nasal and oral cavities simultaneously was discovered only in three out of 96 patients (3.12%). When comparing the group of patients with fixed and removable prostheses to other groups, the occurrence of microorganism studied was significantly higher (p < 0,05). Conclusions: Our results indicate that the oral cavity may be an important site of Staphylococcus aureus colonisation and the conditions in the oral cavity, e.g., fixed and removable restorations may promote oral carriage of this microorganism.

Keywords

• staphylococcus aureus
• methicillin resistant staphylococcus aureus
• oral cavity
• parodontitis
• dental prostheses