ARTICLE Respiratory tract infections during the 2011 Mycoplasma pneumoniae epidemic N. Reinton & L. Manley & T. Tjade & A. Moghaddam Received: 26 November 2012 / Accepted: 6 January 2013 / Published online: 25 January 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract In 2011, Norway experienced a surge in commu- nity acquired Mycoplasma pneumoniae infections. Norway also has one of the highest rates of reported Bordetella pertussis infections, despite high vaccine coverage. We aimed to determine the prevalence of upper respiratory tract pathogens in patients attending primary care physicians for respiratory illness during the 2011 M. pneumoniae epidemic period. A retrospective analysis of data from 26,039 patients that have had nasopharyngeal swabs analysed by nucleic acid amplification testing (NAAT) for M. pneumoniae, C. pneumoniae and B. pertussis was performed. Subsets of samples were tested for additional pathogenic bacteria, in- cluding B. parapertussis and B. holmesii, as well as influ- enza virus. M. pneumoniae, C. pneumoniae and B. pertussis were detected in 2,484 (9.5 %), 261 (1.0 %) and 821 (3.2 %) patients, respectively. Co-infection of M. pneumoniae and B. pertussis was found in 50 (0.19 %) patients, C. pneumo- niae and B. pertussis in 4 (0.02 %). Influenza virus was found in 899 (24.5 %) of 3,661 nasopharyngeal swabs. Co- infection of influenza virus and bacterial pathogens was common, although influenza virus co-infection with B. per- tussis occurred significantly more often than with C. pneu- moniae and M. pneumoniae (20.4 % versus 2.9 % and 9.1 %, respectively; p<0.005). Testing for Bordetella species genes IS1001, IS1002 and recA showed that B. holmesii was most likely misdiagnosed as B. pertussis in 5.8 % of cases. The most prevalent respiratory tract pathogen in the general population in 2011 was M. pneumoniae. B. pertussis was also found frequently as was B. pertussis and influenza virus co-infections. Introduction Bacterial and viral infection of the respiratory tracts is one of the most common reasons for patients attending primary physicians. Respiratory tract infections can be detrimental to individuals and costly to society. Following the world- wide 2009 H1N1 flu pandemic (swine flu) and population- wide vaccinations [1], Europe experienced a Mycoplasma pneumoniae epidemic [2–4]. Over the last several years, there has been a resurgence of Bordetella pertussis, the causative agent of whooping cough, in populations with high vaccination coverage [5, 6]. Hospital laboratories are often equipped with diagnostic tests for a host of viruses and bacteria, such as M. pneumoniae, Chlamydophila pneumo- niae, B. pertussis, Heamophilus influenza, influenza virus, parainfluenza virus, respiratory syncitial virus, adenovirus and metapneumovirus. Diagnostic testing for patients attending primary care centers is also becoming widely available and hence treatment decisions are changing from knowledge of pathogen distribution to actual laboratory test results. However, little data is published from these populations. The private diagnostic laboratory, Fürst Medisinsk Laboratorium, where data for this article originates, serves primary physicians in Oslo and surrounding areas. The laboratory performs nucleic acid amplification testing (NAAT) for common bacterial pathogens of the upper res- piratory tract, M. pneumoniae, C. pneumoniae and B. per- tussis, as well as influenza virus, with guidelines from the Norwegian National Public Health Institute [7]. In 2011, the introduction of these NAAT tests coincided with a population- wide epidemic outbreak of M. pneumoniae. We have ana- lyzed data from patient samples received from 1st January 2011 to the second quarter of 2012, with the aim of deter- mining prevalence of identified pathogens and trends in age N. Reinton : L. Manley : T. Tjade : A. Moghaddam (*) Fürst Medisinsk Laboratorium, Søren Bulls vei 25, 1051 Oslo, Norway e-mail: amoghaddam@furst.no Eur J Clin Microbiol Infect Dis (2013) 32:835–840 DOI 10.1007/s10096-013-1818-8