RESULTS. OBJECTIVES. CONCLUSIONS. MP was detected in 2.9% (9/313) of the studied adults with CA-LRTI by a IgG seroconversion or significant rise in IgG. (Table 1) 3/9 (33%) M. pneumoniae IgG positive patients were also found positive for M. pneumoniae IgM.
Objectives:Diagnosis of atypical bacteria such as M. pneumoniae (MP) is often based on serology, which may require up to 3 weeks for a definite result. PCR based assays offer earlier diagnosis; however often respiratory specimens are not available from patients in a primary care setting. The aim of this study was to evaluate the prevalence of MP infection and compare serology and real-time PCR on both sputum and nasopharyngeal flocked swabs (NPFS) for diagnosis of MP.
Mycoplasma pneumoniae is not an important cause of lower respiratory tract infections in the European GRACE study: a combination of methods is necessary for early detection of casesIeven M.1, Lammens C.1, Loens K.1, Vanderstraeten A.1, Ursi D.1, Dettlaff S.2, Goossens H.1 and the GRACE study team1 University of Antwerp, Antwerp, Belgium; 2 Medac GmbH, Wedel, Germany
MATERIALS & METHODS
Table 1. M. pneumoniae: IgG, IgM and PCR results
Patients: From 10/2007 through 04/2010, a total of 3102 adult patients with LRTI in the community and 2984 controls were enrolled in a 3 year prospective study in 16 primary care networks PCNs in 11 European countries. (Fig. 1).
Samples: Nasopharyngeal flocked swabs (NPFS, Copan, Brescia, Italy),sputa, and paired sera were collected and sent to the local laboratory to be frozen until transport to the central lab in Antwerp.
Methods: Nucleic acids were extracted by using the NucliSEns EasyMAG (Biomérieux, France). On a subset of 374 patients from whom sputa were available in the first winter period, in-house real-time PCR for MP was performed (1) both on the sputum and NPFS. Sputa were scored according to the number of leucocytes (WBC) and squamous epithelial cells (SEC): specimens with ratios of WBC/epithelial cells ≥1 were defined as good quality sputa, ratios <1 were considered low quality sputa. IgG and IgM serology was performed using Mycoplasma pneumoniae-IgG/IgM-ELISA (Medac GmbH, Wedel, Germany) for detection of IgM or a IgG seroconversion or significant rise in anti MP IgG in sera collected 3-4 weeks apart; paired sera were available from 313 patients.
*AU/ml were calculated after 1:10 dilution of the serum.
Table 2. M. pneumoniae: positivity in function of sputum quality
Ursi, D., et al. 2003. DetectionofMycoplasmapneumoniae in respiratorysamplesby real-time PCR using an inhibitioncontrol. J. Microbiol. Methods 55, 149-153.
Figure 1: The 16 primary care networks involved in this study
Greet Ieven, leader WP3, [email protected]
Vaccine & Infectious Disease Institute (VAXINFECTIO)University Hospital Antwerp, Wilrijkstraat 10, B-2650 Edegem, Belgium
This project is supported through Priority 1 (Life Sciences, Genomics and Biotechnology for Health) of European Union's FP6, Contract number: LSHM-CT-2005-518226