Detection of Mycoplasma pneumoniae in adult community-acquired pneumonia by PCR and serology

Abstract

Diagnosis of pneumonia caused by Mycoplasma pneumoniae in adults is hampered by a lack of rapid and standardized tests for detection. This prospective study was conducted to compare the diagnostic values of an indirect immunofluorescence assay and a 16S rRNA gene PCR for the diagnosis of M. pneumoniae pneumonia in adults. From February 2005 to January 2008, 357 patients (53.8 % males, median age 63 years, range 18-94) admitted for community-acquired pneumonia (CAP) to two hospitals in Santiago, Chile, were enrolled in the study. Thirty-two patients (9.0 %) met the criteria of current or recent M. pneumoniae infection, and laboratory diagnosis was definitive in 26 cases (81.2 %) and presumptive in six cases (18.8 %). Among the 32 M. pneumoniae infections, the PCR assay was positive in 23 (71.9 %) and the serology in 27 (84.4 %) of the cases. IgM was positive in acute-phase serum specimens in 13 cases (40.6 %) of M. pneumoniae infections. Using serology as the gold standard, the sensitivity, specificity, and positive and negative predictive values of the PCR were 66.7, 98.5, 78.3 and 97.3 %, respectively, whereas the global agreement of the methods was 343/357 (96.1 %). The frequency of M. pneumoniae CAP cases declined significantly during the second year of study, suggesting the end of an epidemic period. In conclusion, although good global agreement was found between PCR and serology, the lower sensitivity of the PCR leads us to recommend the use of both procedures in parallel to confirm M. pneumoniae in CAP in adults. INTRODUCTIONCommunity-acquired pneumonia (CAP) is a relevant worldwide cause of morbidity and mortality. In spite of technological advances in microbial diagnosis, the aetiology usually remains uncertain and the therapy is empirical, based on the clinical and epidemiological features (Niederman et al., 1993;Fine et al., 1997). Mycoplasma pneumoniae is a common cause of CAP, mainly in children and young adults (Foy, 1993;Waites & Talkington, 2004). During epidemic periods, it also accounts for a significant proportion of acute respiratory tract infections in all age groups (Rastawicki et al., 1998;Layani-Milon et al., 1999). Furthermore, around 25 % of people infected with M. pneumoniae may experience extrapulmonary complications (Waites & Talkington, 2004). M. pneumoniae infections cannot be distinguished clinically from infections caused by viral or other bacterial agents (Foy, 1993;Waites & Talkington, 2004). Thus a rapid and accurate laboratory diagnosis is relevant for an effective therapy and for limiting the spread of infection in the community. The diagnosis of M. pneumoniae infection is currently based principally on serology. The detection of IgM provides an early and sensitive diagnosis in children (Waris et al., 1998;Petitjean et al., 2002). However, several studies have shown that adults fail to respond with IgM, probably as a result of re-infections (Sillis, 1990;Uldum et al., 1992;Jacobs, 1993). As IgG during the acute infection may represent persistent antibodies from past infection...

Mycoplasma pneumoniae infection in hospitalized adult patients with community-acquired pneumonia in China

“…In the present study, the infection rate of M. pneumoniae detected by serology was 46.6% among hospitalized CAP patients. This rate was significantly higher than those (6.8%-29.6%) previously detected by various methods in most studies [12][13][14][15][16]. However, this rate is consistent with the one recently reported by Tao et al in Chinese patients with CAP, in whom M. pneumoniae infection was the most frequently identified pathogen, detected by serological tests in 38.9% of CAP patients and in 45.7% and 24.4% of young (< 65 years of age) and old patients, respectively [10].…”

Importance of Functional Assessment in the Management of Community-acquired and Healthcare-associated Pneumonia

“…However, because about 60% of patients in the All-B group were suspected to have developed aspiration pneumonia, treatment to cover anaerobic pathogens should be prescribed for patients with decreased ADL. Second, previous studies indicated that the sensitivity of IgM antibodies against Mycoplasma pneumoniae was 33.3% (26). Therefore, our diagnosis using IgM against Mycoplasma pneumoniae might be insufficient.…”

Detection of Mycoplasma pneumoniae Among Children with Pneumonia Using Bacterial Culture, Polymerase Chain Reaction, and the Enzyme-linked Immunosorbent Assay Techniques in Ahvaz, Iran

“…In accordance with the current study data, Morozumi (26) and Medjo (22) found similar specificities, while the sensitivity rates were higher in their studies than those of the current study. On the other hand, some researchers reported lower sensitivity and specificity of PCR method in comparison with those of the IgG serology (24,27). These differences in the results of such studies could be due to PCR types (conventional PCR or RT-PCR), gene targets used for amplification reaction, sample type, or time of sampling.…”

“…There are some controversies about the gold standard method to diagnose M. pneumoniae. Some authors indicated that the bacterial culture is a gold standard (23), while others mentioned that PCR or serology tests were the gold standard methods to diagnose acute Mycoplasma infection (24). In the current study, the acute infection was diagnosed in 16 cases, based on the combination of an IgM (25).…”