Previous antibiotic exposure and antibiotic resistance of commensal Staphylococcus aureus in Spanish primary care

Abstract

Introduction: Commensal flora of healthy people is becoming an important reservoir of resistant bacteria.

Objectives: To evaluate the relationship of previous antibiotic-dispensed and resistance pattern of strains of Staphylococcus aureus in primary care patients.

Methods: A cross-sectional study was carried out in seven primary care centres in Catalonia, Spain, from October 2010 to May 2011, as part of the APRES (The appropriateness of prescribing antibiotics in primary care in Europe concerning antibiotic resistance) study. Outpatients aged 4 or more who did not present an infectious disease and had not taken antibiotic or had not been hospitalised in the previous 3 months were invited to participate. Nasal swabs were collected for S. aureus culture, and antimicrobial susceptibility testing was carried out. Antibiotics dispensed boxes in the previous 4 years were extracted from Information System for Research in Primary Care.

Results: A total of 4,001 nasal swabs were collected, and 3,969 were tested for identification, 765 S. aureus were tested for resistance. Resistance rates to penicillin, azithromycin and methicillin were 87.1%, 11.6% and 1.3%, respectively, and a total of 10 MRSA strains were isolated (1.3%). Penicillin-resistant staphylococci were statistically significantly associated with the previous number of packages of penicillin dispensed (OR, 1.18; 95% CI, 1.04–1.35).

Conclusion: Although no causal inference is possible, an association was observed between previous antibiotic dispensation and isolation of resistant organisms in community-dwelling individuals, mainly between packages of penicillin and penicillin-resistant staphylococci.

Keywords:

• Antibiotics
• Staphylococcus aureus
• carriage
• resistance
• primary health care

Acknowledgements

We acknowledge the patients, GPs, paediatricians and the nurse who participated in this study as well as the contribution of Jesús Almeda, Rosa Morros, Rosa Juvé, Pere Simonet, Laura Prats and Edurne Zabaleta in developing the project. We would also like to thank Francois Schellevis, Mike Pringle, Ellen Stobberingh, Herman Goossens and Gilles Hebbrecht who conducted and coordinated the APRES project and Samuel Coenen for his contribution to the protocol.

List of physicians and nurse participating in this study: Guinardó Primary Care Centre, Barcelona: M. Carme Casanovas Fuste, Jordi Nadal Echevarría, Antonia Herrera Ruiz, M. Asunción Altaba Barceló, Albert Boada Valmaseda. Congrés Primary Care Centre, Barcelona: Natalia López Pareja, M. Ángeles Salvador Millán. Santa Eulàlia Sud,Primary Care Centre L’Hospitalet del Llobregat: Xavier Mas Garriga, Isabel Zamora Casas, Immaculada Cid, Francisco Javier Cañamares Barroso. Viladecans 2 Primary Care Centre, Viladecans: Pere J. Simonet Aineto, Rosa Villafáfila Ferrero, Noelia Esplugas Muñoz, Estefania Sanjuán Sanchís, M. Jesús Llobera Bauza, Concepció García Peláez. Corbera Primary Acre Centre, Corbera de Llobregat: Luis Altmann Muller, Ana M. Embid García. La Gavarra Primary Care Centre, Cornellà del Llobregat: Marta Soler Costa, Jordi Argimon Font, Raquel Martos Medina. Sant Ildefons Primary Care Centre, Cornellà del Llobregat: Manuel Álvarez Fernández, Marta Rosario D'Lacoste Farre, Eulalia Ruiz Gil, Amparo Pallarés Sancho-Tello, Josep Balaguer Martínez.

This work has been carried out under the doctorate programme of the Universitat Autònoma de Barcelona of the doctoral student Albert Boada Valmaseda

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This project was funded by the European Commission, 7th Framework Programme [grant no. 223083]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Albert Boada has received an XB 2015 research grant for research from the Institut Català de la Salut.