The presence of M. pneumoniae in the upper respiratory tract (URT) is common in asymptomatic children, according to study results in PLOS Medicine.
Because current diagnostic tests for the bacterium are unable to differentiate between asymptomatic carriage and symptomatic infection, the authors believe these findings support reconsidering the significance of a positive PCR test result for the presence of this bacterium.
Investigators compared URT swabs and blood culture results from 321 children admitted to hospital with a respiratory tract infection to results from 405 healthy children undergoing an elective surgical procedure.
Using PCR tests, the team discovered that the prevalence of M. pneumoniae did not differ between the asymptomatic group and the symptomatic group, with a prevalence of 21.2% and 16.2% respectively.
"This finding is important as it implies that the daily clinical practice of diagnosing M. pneumoniae RTI is inadequate," the authors concluded. "Specifically, it does not seem appropriate to use the detection of M. pneumoniae in the URT by PCR as a method to diagnose symptomatic RTIs caused by this bacterium."
The authors believe these findings mean a diagnosis of M. pneumoniae–induced RTI cannot be based exclusively on serology or the detection of M. pneumoniae DNA in the URT, and caution should be taken in the interpretation of diagnostic tests for M. pneumoniae.
The authors noted the study's limitations, including the use of a single study site and limited sample size.