Polymerase chain reaction is superior to serology for the diagnosis of acute Mycoplasma pneumoniae infection and reveals a high rate of persistent infection

Abstract

BackgroundDiagnosis of Mycoplasma pneumoniae (MP) infection is traditionally based on serology, which may require more than two weeks for diagnostic antibodies to develop. PCR-based methods offer earlier diagnosis. During a community outbreak of MP infection, we compared semi-nested and real-time PCR of oropharyngeal swabs with serology for diagnosis of MP infection at different time points after disease onset. PCR-positive individuals were followed longitudinally to assess the persistence of MP DNA in throat secretions. We also studied carriage of MP among household contacts and school children.ResultsMP infection was diagnosed in 48 of 164 patients with respiratory tract infection. Forty-five (29%) had detectable MP DNA in oropharynx. A significant increase in MP IgG IgG titre or MP IgM antibodies was detected in 44/154 (27%) subjects. Two MP PCR-positive patients lacked antibody responses. Sera were missing from another two patients. The agreement between serology and PCR was good, κ = 0.90.During the first three weeks after disease onset the performance of PCR was excellent and all patients but one were detected. In contrast, only 21% of the patients with confirmed MP infection were positive by serum 1 during the first symptomatic week (56% during the second and 100% during the third week). Only 1/237 (0.4%) school children was positive by PCR. This child had respiratory symptoms. Eighteen of 22 (75%) symptomatic household contacts were MP PCR positive.Persistence of MP DNA in the throat was common. Median time for carriage of MP DNA was 7 weeks after disease onset (range 2 days – 7 months). Adequate antibiotic treatment did not shorten the period of persistence. Bacterial load, measured by quantitative real-time PCR declined gradually, and all followed patients eventually became PCR-negative.ConclusionPCR is superior to serology for diagnosis of MP infection during the early phases of infection. Persistent, sometimes long-term, carriage of MP DNA in the throat is common following acute infection, and is not affected by antibiotic therapy. Asymptomatic carriage of MP even during an outbreak is uncommon.

Hemólisis, exantema, serositis. Manifestaciones extrapulmonares del Mycoplasma pneumoniae: Reporte de un caso

“…La técnica empleada en nuestro laboratorio (IgM Elisa) tiene una sensibilidad y especificidad de 89,1 y 92,2% respectivamente. Nilsson comparó la sensibilidad de la PCR de secreciones respiratorias versus la detección serológica (IgG e IgM) en pacientes con infección respiratoria por Mycoplasma, destacando que la sensibilidad durante la primera semana del inicio de síntomas fue de 100% para la PCR y 23% para la serología 22 . La presencia de falsos positivos para IgM se puede ver en cuadros producidos por virus de Ebstein Barr, Citomegalovirus y Coronavirus.…”

“…La presencia de falsos positivos para IgM se puede ver en cuadros producidos por virus de Ebstein Barr, Citomegalovirus y Coronavirus. También se pueden ver valores intermedios de IgG e IgM en casos de Sarampión, Virus respiratorio sincicial, Virus Varicela zoster y Chlamidea pneumoniae 22 . En casos dudosos se recomienda la determinación de crioaglutininas.…”

Comparison of P1 and 16S rRNA genes for detection of Mycoplasma pneumoniae by nested PCR in adults in Zhejiang, China

“…It has been suggested that cross-reactivity with antigen preparations used in some of the commercial enzyme immunoassays (EIAs) result in over-diagnosis of M. pneumoniae infections [21]. Therefore, even if serology is a useful epidemiologic tool in areas where the infection rate of M. pneumoniae is high, it is less suited for assessment of individual patients in clinical laboratories [11].…”

“…Serological methods are currently the most common tool used in the clinical laboratory. However, these methods have practical limitations because of the availability of paired serum samples from both acute and convalescent phases, and provide results of questionable specificity and sensitivity [10][11][12].…”

COMPARISON OF ENZYME IMMUNOASSAY WITH IMMUNOFLUORESCENCE ASSAY FOR THE DIAGNOSIS OF <I>MYCOPLASMA PNEUMONIAE</I> RESPIRATORY TRACT INFECTIONS IN CHILDREN

“…Therefore, the sensitivity will increased to 100% (Souliou et al, 2007). The slow growth of M. pneumoniae coupled with lack of suitable commercially available culture media will limits the usefulness of cultural diagnosis and results in reliance on serology and the one of the newer techniques like PCR (Cassel et al, 1996), In the latter method, a nasal or throat swab specimens were analysed for the presence of M. pneumoniae and found it is an easy, reliable and quick diagnostic test in infants and children (Nilsson et al, 2008;Sorensen et al, 2013). We therefore conclude that IgM IFA assay showed relatively lower positivity than ELISA assay in the early acute phase and the use of the commercial ELISA assay in the country as a more reliable laboratory for the accurate and cost-efficient tool for diagnosis of specific IgM antibodies for Mycoplasma pneumoniae respiratory tract infections in children.…”