[Antibiotic susceptibility of Staphylococcus aureus and Streptococcus pneumoniae in healthy carrier individuals in primary care in Barcelona area].

INTRODUCTION: The information available on antibiotic resistance patterns are generally based on specimens from hospitalised individuals. This study was aimed at evaluating the antibiotic resistance rate of nasal carriage strains of Staphylococcus aureus and Streptococcus pneumoniae in healthy individuals, in accordance with age and gender, attended in Primary Care Centres (PCC).

DESIGN: Cross-sectional study.

SETTING: Seven PCC in the Barcelona area.

PARTICIPANTS: Healthy nasal carriers aged 4years or more who did not present with any sign of infectious disease, and had not taken any antibiotic or had been hospitalised in the previous 3months.

MAIN MEASUREMENTS: A total of 3,969 nasal swabs valid for identification were collected between 2010 and 2011 and were sent to one central microbiological laboratory for isolation of both pathogens. Resistance to common antibiotics was determined on the basis of the current European Committee on Antimicrobial Susceptibility Testing guidelines on cut-off points.

RESULTS: The prevalence of methicillin-resistant S.aureus was 1.3% (95%CI: 0.5-2.1%), with resistance rates of 87.1% to phenoxymethylpenicillin and 11.6% to azithromycin, with no significant differences with age and gender. A total of 2.4% (95CI%: 0.1-4.7%) of the pneumococcal strains were highly resistant to both phenoxymethylpenicillin and macrolides, whereas the highest resistance rates were to cefaclor (53.3%), followed by tetracycline (20%) and cefuroxime (12.1%).

CONCLUSIONS: These pathogens have lower resistance rates in the community than in the hospital setting. Primary Care physicians must be more aware of the current antimicrobial resistance, in order to ensure prudent use of antibiotics.