Original StudiesMycoplasma pneumoniae in Children With and Without Community-acquired Pneumonia. What do PCR and Serology Say?Copete, Angela Rocio MSc*; Vera, Cristian MSc*,†; Herrera, Mariana MSc*,†; Aguilar, Yudy Alexandra BS*; Rueda, Zulma Vanessa MD, PhD†; Vélez, Lázaro Agustín MD*Author Information From the *Infectious Diseases Problems Research Group, Section of Infectious Diseases, Facultad de Medicina, University of Antioquia, Medellín, Colombia †Grupo de Investigación en Salud Pública, Research Department, Facultad de Medicina, Universidad Pontificia Bolivariana, Medellín, Colombia. Accepted for publication February 6, 2020. This study was funded by Colciencias (Grant: 111551929199) and the University of Antioquia. The authors have no conflicts of interest to disclose. A.R.C. and C.V. contributed equally to this article. Authors’ contributions: A.R.C. and C.V. conducted the laboratory tests. M.H., C.V. and A.R.C. drafted the article. C.V., A.R.C., M.H., Y.A.A., Z.V.R. and L.A.V. conceived the study; participated in its design, coordination and data analysis; and helped to draft the article. All authors read and approved the final article and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work were appropriately investigated and resolved. This study was approved by the Ethics Committee of the School of Medicine at the University of Antioquia (proceeding number 001 of the year 2015), at each one of the 13 participating institutions. Written informed consent was obtained from the parents or guardians of each child, and informed consent was obtained from children >7 years of age. Furthermore, additional consent to store the samples and use them in subsequent research was obtained. Only patients who authorized the use of their samples were included. Address for correspondence: Angela Rocio Copete, MSc, Grupo Investigador de Problemas en Enfermedades Infecciosas (GRIPE), Sede de Investigación Universitaria, Calle 62 # 52-59, Laboratorio 630, Universidad de Antioquia, Medellín, Colombia. E-mail: firstname.lastname@example.org. The Pediatric Infectious Disease Journal: July 2020 - Volume 39 - Issue 7 - p e104-e108 doi: 10.1097/INF.0000000000002636 Buy Metrics Abstract Background: IgM titers of Mycoplasma pneumoniae can remain high for months or years, and specific DNA can be detected in asymptomatic people. Methods: We compared the performance of serology and PCR in children with and without community-acquired pneumonia (CAP) for the diagnosis of M. pneumoniae. Results: In children with CAP, a positive test by M. pneumoniae (PCR and/or paired serology or both) were found in 13.9%. Of these, 10.3% were positive by multiplex PCR (Seeplex-Seegen), and 6.7% exhibited quadrupled titers (22 for IgG, 6 for IgM and 5 for both). Both tests were positive in 2.8% of cases. In the group without CAP, 3.3% were positive by PCR. Thirty-two percent of children with CAP and 38.3% of healthy children had IgM titers >11 in the acute phase. Conclusions: The detection of IgM is not useful for diagnosing acute M. pneumoniae infection, and a positive PCR result can be due to colonization and not infection. New and better diagnostic techniques are required. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.