The bacterium M. pneumoniae is carried at high rates in the upper respiratory tracts of healthy children and usual diagnostic tests cannot differentiate between such asymptomatic carriage and actual respiratory tract infection, according to a study by Dutch researchers published in this week’s PLOS Medicine.
These findings are important as they suggest that clinicians may need to reconsider the clinical significance of a positive test result for the presence of this bacterium.
The researchers, led by Annemarie van Rossum from Erasmus MC-Sophia in Rotterdam, The Netherlands, reached these conclusions by comparing the upper respiratory tract swabs and blood culture results taken from 321 children (aged 3 months to 16 years) admitted to hospital with a respiratory tract infection with those from 405 healthy children undergoing an elective surgical procedure.
The authors found that the prevalence of M. pneumoniae (as measured using PCR tests) did not differ between the asymptomatic group and the symptomatic group, with a prevalence of 21.2% and 16.2% respectively. There was also no difference in prevalence when diagnosed using blood tests. In addition, a high rate of other bacteria and viruses was found in both asymptomatic and symptomatic children.
The authors also report a wide variation in asymptomatic carriage of M. pneumoniae ranging from 3% during the spring of 2009 to 58% during the summer of 2010. And in 21 children from the asymptomatic group who participated in a follow up study, 15 (71%) tested negative within one month and in the symptomatic group, 19 of 22 children (86%) tested negative after the first visit.
The authors say: “Although our study has limitations, such as a single study site and limited sample size, our data indicate that the presence of M. pneumoniae in the upper respiratory tract is common in asymptomatic children.”
They continue: “The current diagnostic tests for M. pneumoniae are unable to differentiate between asymptomatic carriage and symptomatic infection.”
The authors add: “Therefore, clinicians may need to readdress the clinical significance of a positive test result.”
“Carriage of Mycoplasma pneumoniae in the Upper Respiratory Tract of Symptomatic and Asymptomatic Children: An Observational Study”,
Spuesens EBM, Fraaij PLA, Visser EG, Hoogenboezem T, Hop WCJ, et al. (2013)
PLoS Med. 10(5): e1001444. doi:10.1371/journal.pmed.1001444
Funding: ‘‘Stichting Vrienden van het Sophia,’’ Rotterdam, The Netherlands. AMR was supported for this study by an Erasmus MC Fellowship Award, a Clinical Fellowship Award of The Netherlands Organisation for Health Research and Development, and a Fellowship Award of the European Society for PaediatricInfectious Diseases. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: At the time of the study, AB was a paid member on the Cepheid Scientific Advisory Board in which he is no longer taking part. After the study, AB joined bioMe´ rieux, a company specializing in infectious disease’ diagnostics. ADO is Head of the department of Virology of the Erasmus MC. He is involved in or with many initiatives within the virology field. This involvement ranges from expert advice to various international organisations involved in the area of general human and veterinary health to advising spin-out companies of the Erasmus University Medical Center Rotterdam that are endeavouring to bridge the gap between scientific discovery/knowledge and putting these to practical use in society. For purposes of transparency and to avoid of possible conflicts of interest, Professor Osterhaus discloses all his interests in matters related, directly or indirectly, to his position as head of the Department of Virology of Erasmus MC. Professor Osterhaus has share certificates in Viroclinics Biosciences B.V. AMR received fees for speaking from Abbott. AMR has received grants from the NutsOhra Foundation, The Netherlands, and the Thrasher Fund, USA. All other authors have declared that no competing interests exist.