Diagnosis of Mycoplasma pneumoniae Pneumonia in Children

Abstract

We evaluated a commercial immunoglobulin M (IgM)-capture immunoassay for the detection of Mycoplasma pneumoniaeinfections in 278 pediatric patients with community-acquired, radiographically defined pneumonia. Acute- and convalescent-phase serum samples were collected from all patients and were tested for M. pneumoniae-specific IgM and IgG antibodies by Platelia enzyme immunoassays (Sanofi Diagnostica Pasteur, Marnes la Coquette, France). Nasopharyngeal aspirates (NPAs) were collected at the time of admission to the hospital. A total of 227 NPAs were subjected to the detection ofM. pneumoniae DNA by PCR, and 191 NPAs were cultured by using the Pneumofast kit (International Mycoplasma, Signeswere, France). Southern hybridization of PCR products and the IgM test with solid-phase antigen (Serion Immunodiagnostica, Würzburg, Germany) were used for additional confirmation of a positive result, which required agreement of at least two different methods. A total of 24 (9%) confirmed diagnoses of mycoplasma infection were made, 5 (21%) of which were in children <5 years of age. Of the positive children, 24 of 24 (sensitivity, 100%) were positive by the IgM-capture test with convalescent-phase serum, 19 of 24 (79%) were positive by the IgM-capture test with acute-phase serum, 19 of 24 (79%) were positive by IgG serology, 10 of 20 (50%) were positive by PCR, and 8 of 17 (47%) were positive by culture. An additional 5 (of 254) children were positive by the Platelia IgM test alone (specificity, 98%). When the PCR with Southern hybridization result was combined with the IgM-capture test result with the acute-phase sera, the sensitivity of rapid laboratory diagnosis increased to 95%. In conclusion, the IgM serology test was the single most valuable tool for the diagnosis ofM. pneumoniae pneumonia in children of any age.

Practice Guidelines for the Management of Community-Acquired Pneumonia in Adults

“…Cold agglutinins in a titer у1:64 support the diagnosis of M. pneumoniae infection, with a sensitivity of 30%-60%, but this test has poor specificity. IgM antibodies to M. pneumoniae require up to 1 week to reach diagnostic titers; reported results for sensitivity are variable [94,95]. The serological responses to Chlamydia and Legionella species take even longer [96,97].…”

“…Laboratory tests to confirm infection due to M. pneumoniae include culture, serology, and PCR [48,66,94,95]. Fastidious growth requirements and long incubation periods limit utility of culture, and most laboratories do not offer this test.…”

“…Fastidious growth requirements and long incubation periods limit utility of culture, and most laboratories do not offer this test. IgM and IgG antibody values become elevated in most cases, but the response is often delayed, so the utility of these tests for early detection is limited, and reported results are variable [94,95]. Some authorities consider PCR to be particularly promising [66,94].…”

Infections à Mycoplasma pneumoniae : étude rétrospective en Basse-Normandie de 1997 à 2005. Épidémiologie –– Place de la sérologie et de la PCR pour le diagnostic

“…Chez l'enfant, la détection des IgM anti-Mpn est un bon marqueur d'infection récente et le plus souvent, dès le premier prélèvement, on observe des titres élevés d'IgM et IgG [18,29,31]. Chez l'adulte, les IgM peuvent être absentes (réinfection) et leur présence est toujours difficile à interpréter : infection active primaire ou secondaire, activation polyclonale non spécifique, croisement antigénique, interférence du FR.…”

“…Parmi [18,25,27,29,31,33,35]. Les discordances -sérologie positive/PCR négative -peuvent s'expliquer par l'existence d'une charge bactérienne faible, en dessous du seuil de détection, du fait d'un prélèvement retardé ou plus probablement d'un prélèvement défectueux.…”