Application of PCR for Mycoplasma pneumoniae detection in children with community-acquired pneumonia

Expert consensus on the diagnosis and treatment of macrolide-resistant Mycoplasma pneumoniae pneumonia in children

BACKGROUND

Mycoplasma pneumoniae (M. pneumoniae) is a significant contributor to community-acquired pneumonia among children. Since 1968, when a strain of M. pneumoniae resistant to macrolide antibiotics was initially reported in Japan, macrolide-resistant M. pneumoniae (MRMP) has been documented in many countries worldwide, with varying incidence rates. MRMP infections lead to a poor response to macrolide antibiotics, frequently resulting in prolonged fever, extended antibiotic treatment, increased hospitalization, intensive care unit admissions, and a significantly higher proportion of patients receiving glucocorticoids or second-line antibiotics. Since 2000, the global incidence of MRMP has gradually increased, especially in East Asia, which has posed a serious challenge to the treatment of M. pneumoniae infections in children and attracted widespread attention from pediatricians. However, there is still no global consensus on the diagnosis and treatment of MRMP in children.

METHODS

We organized 29 Chinese experts majoring in pediatric pulmonology and epidemiology to write the world's first consensus on the diagnosis and treatment of pediatric MRMP pneumonia, based on evidence collection. The evidence searches and reviews were conducted using electronic databases, including PubMed, Embase, Web of Science, CNKI, Medline, and the Cochrane Library. We used variations in terms for "macrolide-resistant", "Mycoplasma pneumoniae", "MP", "M. pneumoniae", "pneumonia", "MRMP", "lower respiratory tract infection", "Mycoplasma pneumoniae infection", "children", and "pediatric".

RESULTS

Epidemiology, pathogenesis, clinical manifestations, early identification, laboratory examination, principles of antibiotic use, application of glucocorticoids and intravenous immunoglobulin, and precautions for bronchoscopy are highlighted. Early and rapid identification of gene mutations associated with MRMP is now available by polymerase chain reaction and fluorescent probe techniques in respiratory specimens. Although the resistance rate to macrolide remains high, it is fortunate that M. pneumoniae still maintains good in vitro sensitivity to second-line antibiotics such as tetracyclines and quinolones, making them an effective treatment option for patients with initial treatment failure caused by macrolide antibiotics.

CONCLUSIONS

This consensus, based on international and national scientific evidence, provides scientific guidance for the diagnosis and treatment of MRMP in children. Further studies on tetracycline and quinolone drugs in children are urgently needed to evaluate their effects on the growth and development. Additionally, developing an antibiotic rotation treatment strategy is necessary to reduce the prevalence of MRMP strains.

Implementation of Point-of-Care Molecular Diagnostics for Mycoplasma pneumoniae Ensures the Correct Antimicrobial Prescription for Pediatric Pneumonia Patients

Mycoplasma pneumoniae is a leading causative pathogen of pneumonia among pediatric patients, and its accurate diagnosis may aid in the selection of appropriate antimicrobial agents. We established a rapid reporting system of a polymerase chain reaction (PCR) examination for M. pneumoniae that enables physicians to obtain test results approximately 90 minutes after ordering the test. In this study, we evaluated the impact of this system on antimicrobial prescriptions for pediatric pneumonia patients after its implementation from May 2016 to April 2017. In total, we identified 375 pediatric pneumonia patients, and the results of the rapid PCR examinations for Mycoplasma pneumoniae were reported immediately in 90.7% of patients (340/375), with physicians able to use these results to decide on patients' management before the prescription of antimicrobial agents. Of the 375 pediatric pneumoniae patients, M. pneumoniae was detected in 223 (59.5%). Among the 223 M. pneumoniae-positive pneumonia cases, antimicrobial agents for atypical pathogens (macrolides, tetracyclines or quinolones) were prescribed in 97.3% (217/223) at the initial evaluation, and their prescription rates increased to 99.1% (221/223) during management. In contrast, antimicrobial agents for atypical pathogens were prescribed only in 10.5% of 152 M. pneumoniae-negative pneumonia cases at the initial evaluations, and only 1 additional case was prescribed clarithromycin for persistent symptoms during management. In conclusion, we show that molecular technology could be applicable in the field of point-of-care testing in infectious disease, and its implementation will ensure the correct antimicrobial prescription for pediatric pneumonia patients.

Bullous Skin Manifestations of Mycoplasma pneumoniae Infection: A Case Series

Bullous skin lesions are uncommon in children. While it is well known that Mycoplasma infections are associated with papular skin manifestations, bullous skin lesions are not commonly reported. Mycoplasma pneumoniae is a very common bacterial pathogen causing respiratory tract infection in children and adults. We report 2 children with serology-confirmed Mycoplasma infection who were hospitalized for blistering skin lesions. Both of our patients responded well to corticosteroids and one of them required intravenous immunoglobulin. The aim of this case report is to raise awareness that Mycoplasma pneumoniae infection can present with bullous skin lesions, and to briefly review the pathophysiology, diagnosis, and management of the skin manifestation of Mycoplasma infection.

The Evolution of Advanced Molecular Diagnostics for the Detection and Characterization of Mycoplasma pneumoniae

Over the past decade there have been significant advancements in the methods used for detecting and characterizing Mycoplasma pneumoniae, a common cause of respiratory illness and community-acquired pneumonia worldwide. The repertoire of available molecular diagnostics has greatly expanded from nucleic acid amplification techniques (NAATs) that encompass a variety of chemistries used for detection, to more sophisticated characterizing methods such as multi-locus variable-number tandem-repeat analysis (MLVA), Multi-locus sequence typing (MLST), matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS), single nucleotide polymorphism typing, and numerous macrolide susceptibility profiling methods, among others. These many molecular-based approaches have been developed and employed to continually increase the level of discrimination and characterization in order to better understand the epidemiology and biology of M. pneumoniae. This review will summarize recent molecular techniques and procedures and lend perspective to how each has enhanced the current understanding of this organism and will emphasize how Next Generation Sequencing may serve as a resource for researchers to gain a more comprehensive understanding of the genomic complexities of this insidious pathogen.

Accuracy of IgM antibody testing, FQ-PCR and culture in laboratory diagnosis of acute infection by Mycoplasma pneumoniae in adults and adolescents with community-acquired pneumonia

Background

Diagnosis of community-acquired pneumonia (CAP) caused by Mycoplasma pneumoniae in adults and adolescents is hampered by a lack of rapid and standardized tests for detection.

Methods

CAP patients from 12 teaching hospitals were prospectively and consecutively recruited. Basic and clinical information, throat swabs and paired sera were collected. Mycoplasma pneumoniae was detected by IgG and IgM antibody tests, fluorescence quantitative polymerase chain reaction (FQ-PCR) and culture. A comparative study of the diagnostic values of three methods, including sensitivity, specificity, positive and negative predictive values and positive likelihood ratio (PLR) was conducted. A fourfold or greater increase of IgG antibody titers of paired sera was set as the diagnostic “gold standard”.

Results

One hundred and twenty-five CAP patients (52.8% males, median age 47 years, range 14–85) were enrolled. Twenty-seven (21.6%) patients were diagnosed with acute Mycoplasma pneumoniae infections by the “gold standard”. Specificity values of all three methods were around 90%. An increasing trend of sensitivity, positive predictive value and PLR was found, with the lowest in IgM testing (7.4%, 28.6% and 1.45), intermediate in FQ-PCR (40.7%, 50% and 3.63), and highest in culture (55.6%, 75% and 10.9).

Conclusions

In the defined group of patients, there was a good agreement between positive rate of MP cultivation of throat swabs and acute M. pneumoniae infection (PLR of 10.9). Since the sensitivity is low in all of the evaluated methods, the logical approach would be to incorporate PCR, culture and serological tests for optimum diagnosis of acute Mycoplasma pneumoniae infections in adults and adolescents.

Multiple organ dysfunction syndrome associated with Mycoplasma pneumoniae infection

In this study, we report one case of a three-year-old boy infected with Mycoplasma pneumonia (MP) and presenting concomitant multiple organ damage of the heart, kidney, lung and liver, among others, together with a brief review for the diagnosis and treatment of MP infection with multiple organ dysfunction syndrome (MODS).

Acute respiratory infection due to Mycoplasma pneumoniae: current status of diagnostic methods

Because of the absence of well-standardized both in-house and FDA-approved commercially available diagnostic tests, the reliable diagnosis of respiratory infection due to Mycoplasma pneumoniae remains difficult. In addition, no formal external quality assessment schemes which would allow to conclude about the performance of M. pneumoniae diagnostic tests exist. In this review, the current state of knowledge of M. pneumoniae-associated respiratory infections in the context of epidemiological studies published during the past 5 years is discussed, with particular emphasis on the diagnostic strategies used and their impact on results. The role of M. pneumoniae as a cause of respiratory tract infections (RTIs) differs from study to study due to geographical and epidemiological differences, as well as to the application of different diagnostic techniques and criteria used.

Macrolide-resistant Mycoplasma pneumoniae: characteristics of isolates and clinical aspects of community-acquired pneumonia

Mycoplasma pneumoniae is one of the main pathogens causing community-acquired respiratory tract infections in children and adults. Macrolide (ML) antibiotics are recognized generally as first-choice agents for M. pneumoniae infections, and these antibiotics were thought to have excellent effectiveness against M. pneumoniae for many years. In 2000, however, M. pneumoniae showing resistance to macrolides was isolated from clinical samples obtained from Japanese pediatric patients with community-acquired pneumonia (CAP). Since then, prevalence of ML-resistant M. pneumoniae isolates in pediatric patients has increased rapidly. In 2007, ML-resistant M. pneumoniae isolates were obtained from Japanese adults with CAP; numbers of such isolates also have gradually increased in Japan. Recently, similar antimicrobial resistance in M. pneumoniae has begun to emerge worldwide. In this review, we focus on changes of ML-resistant M. pneumoniae from year to year and consider resistance mechanisms as well as clinical features of patients with resistant M. pneumoniae infection.

Application of cell culture enrichment for improving the sensitivity of mycoplasma detection methods based on nucleic acid amplification technology (NAT)

Herein, we present data demonstrating that the application of initial cell culture enrichment could significantly improve mycoplasma testing methods based on the nucleic acid amplification technology (NAT) including a polymerase chain reaction (PCR)/microarray method. The results of the study using Vero cells demonstrated that this cell culture is able (1) to support efficient growth of mycoplasmas of primary interest, i.e., species found to be cell line contaminants, (2) to increase the sensitivity of NAT assay to the detection limits of the conventional broth/agar culture methods, and (3) to reduce the time required for mycoplasma testing fourfold in comparison with the conventional methods. Detection and identification of mycoplasmal agents were conducted using a modified PCR/microarray assay based on genetic differences among Mollicutes in the 16S-23S rRNA intergenic transcribed spacer (ITS). The application of nano-gold/silver enhancement technology instead of previously used fluorescent dyes significantly simplified the readout of microarray results and allowed us to avoid using expensive scanning equipment. This modification has the potential to expand the implementation of microarray techniques into laboratories involved in diagnostic testing of mycoplasma contamination in cell substrates and potentially in other biological and pharmaceutical products.

Mycoplasma pneumoniae and atypical Stevens-Johnson syndrome: a case series

Mycoplasma pneumoniae is a common cause of community-acquired respiratory illness in the adolescent population. Stevens-Johnson syndrome is an extrapulmonary manifestation that has been associated with M. pneumoniae infections. Three adolescent males presented within a 1-month period with M. pneumoniae respiratory illnesses and severe mucositis but without the classic rash typical of Stevens-Johnson. Diagnosis was facilitated by the use of a polymerase chain reaction-based assay. This case series highlights the potential for M. pneumoniae-associated Stevens-Johnson syndrome to occur without rash and supports the use of polymerase chain reaction for early diagnosis.

Utility of a rapid diagnosis kit for Mycoplasma pneumoniae pneumonia in children, and the antimicrobial susceptibility of the isolates

We evaluated a kit for the rapid diagnosis of Mycoplasma pneumoniae infection and investigated the antimicrobial susceptibility of the isolates. A total of 194 otherwise healthy children, aged 0.3-14.9 years, were diagnosed as having pneumonia by chest X-ray findings between December 2003 and November 2004, and were admitted to Showa Hospital. Isolation of M. pneumoniae was attempted from a throat swab obtained on admission, and the complement fixation titer was measured in paired serum samples obtained at admission and at the convalescent stage. We also used a rapid diagnosis kit (ImmunoCard Mycoplasma) for the detection of specific immunoglobulin M antibody in paired sera. Pneumonia due to M. pneumoniae was defined by isolation of this microorganism, or by seroconversion, or a >or=4-fold increase in the antibody titer. Using each isolate, we determined the minimum inhibitory concentrations for five antimicrobial agents by the broth dilution method. M. pneumoniae pneumonia was diagnosed in 45 children (23.2%). The ImmunoCard had a sensitivity of 31.8% using admission serum and 88.6% using paired sera, while the specificity was 78.1% and 70.5%, respectively. M. pneumoniae was isolated from 14 of the 45 patients (31.1%). The 50%/90% minimum inhibitory concentration (microg/ml) of erythromycin, clarithromycin, azithromycin, minocycline, and levofloxacin was 0.006/0.012, <or=0.003/<or=0.003, <or=0.003/<or=0.003, 0.78/1.56, and 0.39/0.78, respectively. For a rapid diagnosis of M. pneumoniae pneumonia, the ImmunoCard was not effective. Macrolides showed superior in vitro antimicrobial activity against M. pneumoniae isolates causing pediatric pneumonia.

Assessment of real-time PCR for diagnosis of Mycoplasma pneumoniae pneumonia in pediatric patients

We developed a real-time PCR to detect Mycoplasma pneumoniae with a primer set designed for the 16S rRNA gene. Clinical samples (n=937) were collected from children with community-acquired pneumonia between April 2002 and March 2004 at 12 Japanese medical institutions. Sensitivity of real-time PCR was calculated as 10 colony-forming units per reaction tube using a pMP01 plasmid carrying a 225-bp target DNA fragment of the 16S rRNA gene in M. pneumoniae M129, a standard strain. Results, obtained within 2 h, were compared with those of conventional culture and serologic methods. Of all cases tested, 151 (16.4%) and 129 (13.8%) were positive for M. pneumoniae by real-time PCR and by culture, respectively. Among the 151 cases, almost all of those tested serologically by passive agglutination showed a rise in M. pneumoniae antibody titre between acute and convalescent sera. We conclude that this real-time PCR can identify M. pneumoniae rapidly and fulfills the need for rapid identification, high sensitivity, and high specificity.

Emergence of macrolide-resistant Mycoplasma pneumoniae with a 23S rRNA gene mutation

A total of 195 Mycoplasma pneumoniae strains were isolated from 2,462 clinical specimens collected between April 2002 and March 2004 from pediatric outpatients with respiratory tract infections. Susceptibilities to six macrolide antibiotics (ML), telithromycin, minocycline, levofloxacin, and sitafloxacin were determined by the microdilution method using PPLO broth. A total of 183 M. pneumoniae isolates were susceptible to all agents and had excellent MIC90s in the following order: 0.00195 microg/ml for azithromycin and telithromycin, 0.0078 microg/ml for clarithromycin, 0.0156 microg/ml for erythromycin, 0.0625 microg/ml for sitafloxacin, 0.5 microg/ml for minocycline, and 1 microg/ml for levofloxacin. Notably, 12 ML-resistant M. pneumoniae strains were isolated from patients with pneumonia (10 strains) or acute bronchitis (2 strains). These strains showed resistance to ML with MICs of >or=1 microg/ml, except to rokitamycin. Transition mutations of A2063G or A2064G, which correspond to A2058 and A2059 in Escherichia coli, in domain V on the 23S rRNA gene in 11 ML-resistant strains were identified. By pulsed-field gel electrophoresis typing, these strains were classified into groups I and IIb [corrected] as described previously (A. Cousin-Allery, A. Charron, B. D. Barbeyrac, G. Fremy, J. S. Jensen, H. Renaudin, and C. Bebear, Epidemiol. Infect. 124:103-111, 2000). These findings suggest that excessive usage of MLs acts as a trigger to select mutations on the corresponding 23S rRNA gene with the resultant occurrence of ML-resistant M. pneumoniae. Monitoring ML susceptibilities for M. pneumoniae is necessary in the future.