Mycoplasma pneumoniae Common in Asymptomatic Children

Troy Brown

May 15, 2013

Mycoplasma pneumoniae is commonly present in the upper respiratory tract of asymptomatic children, according to a cross-sectional study of 726 children.

Emiel B.M. Spuesens, a PhD student in the Department of Paediatric Infectious Diseases and Immunology and the Laboratory of Paediatrics at Erasmus Medical Center-Sophia in Rotterdam, the Netherlands, and colleagues report their findings in an article published online May 14 in PLOS Medicine.

The study's primary objective was to use current diagnostic methods, particularly polymerase chain reaction (PCR), to differentiate between colonization and symptomatic infection with M pneumoniae.

They enrolled 726 children aged 3 months to 16 years in the study: 405 in the asymptomatic group (healthy children undergoing elective surgery) and 321 in the symptomatic group (children admitted to the hospital with a respiratory tract infection [RTI]). Clinical data, pharyngeal and nasopharyngeal specimens, and serum samples were obtained.

There was no significant difference in the prevalence of M pneumoniae by real-time PCR (P = .11) between the asymptomatic group (21.2%; 95% confidence interval [CI], 17.2% - 25.2%; n = 85) and the symptomatic group (16.2%; 95% CI, 12.2% - 20.2%; n = 51).

There was also no significant difference in the prevalence of M pneumoniae by culture (P = .52) between the asymptomatic group (1.0%; 95% CI, 0.03% - 1.97%; n = 4) and the symptomatic group (1.6%; 95% CI, 0.23% - 2.97%; n = 5).

In the group of symptomatic children, the prevalence of M pneumoniae by real-time PCR was not significantly different (P = .85) between those with a lower RTI (15.6%; 95% CI, 11.6% - 19.6%; n = 10) and those with an upper RTI (15.9%; 95% CI, 11.9% - 19.9%; n = 41).

The researchers also conducted a longitudinal follow-up study among children who were positive for M pneumoniae by PCR. Of the 43 children who were eligible for inclusion, 21 children came from the asymptomatic group and 22 came from the symptomatic group. A total of 15 (71%) of the asymptomatic children and 19 (86%) of the symptomatic children tested negative after 1 month. At 2 months, 6 of the asymptomatic children and 3 of the symptomatic children tested positive. At 3 months, 2 of the asymptomatic children and none of the symptomatic children tested positive.

The investigators also tested 202 children (112 asymptomatic children and 90 symptomatic children) for other bacterial and viral pathogens. They identified 2 or more pathogens in 63 (56%) of the asymptomatic children and 50 (55.5%) of the symptomatic children.

"[A] diagnosis of M. pneumoniae–induced [respiratory tract disease] cannot be based exclusively on serology or the detection of M. pneumoniae DNA in the [upper respiratory tract], and caution should be taken in the interpretation of diagnostic tests for M. pneumoniae," the authors write.

"[The study] is interesting, but it does not make life for the practicing physician any easier than before," said Anastassios Koumbourlis, MD, chief of pulmonary and sleep medicine at Children's National Medical Center in Washington, DC, told Medscape Medical News in a telephone interview.

"Physicians need to use their clinical judgment...they cannot decide on the treatment entirely on the presence of the organism," said Dr. Koumbourlis, who was not involved in the study.

"If the clinical characteristics of the symptoms...look like Mycoplasma pneumoniae, and I know that this organism is very prevalent in the community, I would...treat it as such," Dr. Koumbourlis explained.

The researchers presented an earlier version of their results at the European Society for Paediatric Infectious Diseases (ESPID) 30th Annual Meeting in 2012.

One coauthor was supported 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 Paediatric Infectious Diseases, as well as receiving grant funding from NutsOhra Foundation, The Netherlands, and the Thrasher Fund. One coauthor was a paid member on the Cepheid Scientific Advisory Board at the time of the study. After the study he joined bioMérieux, a company specializing in infectious disease diagnostics. One coauthor is head of the Department of Virology at Erasmus MC; reports a variety of relationships in the virology field, including advising international human and veterinary health organizations; and has share certificates in Viroclinics Biosciences BV. The other authors and Dr. Koumbourlis have disclosed no relevant financial relationships.

PLOS Med. Published online May 14, 2013. Full text


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