Introduction
Approximately 85% of antibiotics in Spain are prescribed to outpatients, but information available on the antibiotic resistance profile is nearly exclusively based on specimens from hospitalised patients, mainly those with severe and invasive infectious diseases [1]. It is well established that the prevalence of resistance to antibiotics greatly depends on their use since increased consumption of these drugs may not only produce higher resistance at the individual patient level but may also spur greater resistance at the community level, which can harm individual patients. The relationship between antibiotic consumption and the emergence of resistant pathogenic germs is well established [1,2], but evidence about previous antibiotic use regarding the isolation of resistant commensal germs in otherwise healthy individuals is scarce.
Staphylococcus aureus is a commensal organism that is widely distributed in nature. Approximately 20%–30% of healthy people carry this organism, mostly in the nose [3]. Carriage of S. aureus rarely causes disease in healthy individuals, but it is associated with an increased risk for the emergence of infections in various populations. Individuals in the community mostly become infected with their own carriage strain [4]. Since the introduction of antibiotics, S. aureus has quickly become resistant to many relevant antibiotics such as β-lactams and macrolides [4,5]. Antibiotic-resistant strains, such as methicillin-resistant S. aureus (MRSA), have emerged as a significant threat in both the hospital and community settings [6]. Several studies in healthy individuals in the general population and in children or specific groups have shown resistance to S. aureus [7–12]. Therefore, studies on the probable association between consumption of antibiotics by the individual and resistance to S. aureus in the general population are needed.
The APRES (The appropriateness of prescribing antibiotics in primary care in Europe concerning antibiotic resistance) project aimed at providing information and recommendations on the appropriateness of prescribing antibiotics in primary health care in nine European countries and was funded by the European Commission [12]. Several papers on the prevalence of S. aureus and pneumococcus carriage, and the association with demographic variables and antibiotic resistance, have been published so far [10–15]. However, information about previous individual antibiotic exposure was only available in Spain.
Therefore, we evaluated the association between previous antibiotic reimbursement data with antibiotic resistance profiles in healthy individuals with nasal carriage of staphylococci in primary care in Catalonia (Spain).