Mycoplasma pneumoniae infections

Real-time fluorescent multiple cross displacement amplification for rapid and sensitive Mycoplasma pneumoniae detection

Mycoplasma pneumoniae is a significant pathogen responsible for community-acquired pneumonia, predominantly affecting children and adolescents. Here, we devised a rapid method for M. pneumoniae that combined multiple cross displacement amplification (MCDA) with real-time fluorescence technology. A set of ten primers, which were specifically designed for M. pneumoniae detection, were employed in a real-time fluorescence MCDA reaction. Of these, one primer incorporated a restriction endonuclease recognition sequence, a fluorophore, and a quencher, facilitating real-time fluorescence detection. The real-time (RT)-MCDA reactions were monitored in a simple real-time fluorescence instrument and conducted under optimised conditions (64°C for 40 min). The detection limit of the M. pneumoniae RT-MCDA assay for genomic DNA extracted from M. pneumoniae culture was down to 43 fg/µl. This assay accurately identified M. pneumoniae strains without cross-reacting with other bacteria. To validate its practical application, we tested the M. pneumoniae RT-MCDA assay using genomic DNA extracted from clinical samples. The assay's detection capability proved comparable with real-time PCR, MCDA-based biosensor detection, and visual inspection under blue light. The entire process, including rapid DNA extraction and real-time MCDA detection, was completed within 1 h. Overall, the M. pneumoniae RT-MCDA assay reported here is a simple and effective diagnostic tool for rapid M. pneumoniae detection, which holds significant potential for point-of-care testing and in resource-limited regions.

Challenges in the treatment of pediatric Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae (MP) is an important cause of community-acquired pneumonia in children and young adolescents. Despite macrolide antibiotics effectiveness as a first-line therapy, persistence of fever and/or clinical deterioration sometimes may complicate treatment and may even lead to severe systemic disease. To date, there is no consensus on alternative treatment options, optimal dosage, and duration for treating severe, progressive, and systemic MP pneumonia after macrolide treatment failure. Macrolide-resistant MP pneumonia and refractory MP pneumonia are the two major complex conditions that are clinically encountered. Currently, the vast majority of MP isolates are resistant to macrolides in East Asia, especially China, whereas in Europe and North America, whereas in Europe and North America prevalence is substantially lower than in Asia, varying across countries. The severity of pneumonia and extrapulmonary presentations may reflect the intensity of the host's immune reaction or the dissemination of bacterial infection. Children infected with macrolide-resistant MP strains who receive macrolide treatment experience persistent fever with extended antibiotic therapy and minimal decrease in MP-DNA load. Alternative second-line agents such as tetracyclines (doxycycline or minocycline) and fluoroquinolones (ciprofloxacin or levofloxacin) may lead to clinical improvement after macrolide treatment failure in children. Refractory MP pneumonia reflects a deterioration of clinical and radiological findings due to excessive immune response against the infection. Immunomodulators such as corticosteroids and intravenous immunoglobulin (IVIG) have shown promising results in treatment of refractory MP pneumonia, particularly when combined with appropriate antimicrobials. Corticosteroid-resistant hyperinflammatory MP pneumonia represents a persistent or recrudescent fever despite corticosteroid therapy with intravenous methylprednisolone at standard dosage.

CONCLUSION

 This report summarizes the clinical significance of macrolide-resistant and refractory MP pneumonia and discusses the efficacy and safety of alternative drugs, with a stepwise approach to the management of MP pneumonia recommended from the viewpoint of clinical practice.

WHAT IS KNOWN

• Although MP pneumonia is usually a benign self-limited infection with response macrolides as first line therapy, severe life-threatening cases may develop if additional treatment strategies are not effectively implemented. • Macrolide-resistant and refractory MP pneumonia are two conditions that may complicate the clinical course of MP pneumonia, increasing the risk for exacerbation and even death.

WHAT IS NEW

• This report summarizes the clinical relevance of macrolide-resistant and refractory MP pneumonia and discusses the efficacy and safety of alternative drug therapies. • A practical stepwise approach to the management of MP pneumonia is developed based on a comprehensive analysis of existing evidence and expert opinion.

Mycoplasma pneumoniae Outbreak in 2023: Post-pandemic Resurgence of an Atypical Bacterial Pathogen

The syndromic nature of infections caused by pneumonia-causing pathogens including Mycoplasma pneumoniae necessitates detection via multiplex PCR for accurate and timely diagnosis to control the infection spread. In this study, we demonstrate an increase in the detection of M. pneumoniae in the outpatient population, during 2023, as compared to the previous two years (2021-2022). In this aggregated survey, respiratory samples collected within the continental United States were tested for the presence of M. pneumoniae and other respiratory bacterial and viral pathogens using a multiplex PCR assay. Patient data was analyzed on the basis of age, gender and geographical location. The positive detection of M. pneumoniae in 2021 and 2022 was 0.004% and 0.006%, respectively. The positivity rate of M. pneumoniae in 2023 increased to 0.21%. The highest proportion of M. pneumoniae cases were detected from Georgia with the outbreak generally concentrated in large urban settings. Median age of the patients testing positive for M. pneumoniae was 10 (interquartile range [IQR] 8-18) years with an almost equal distribution between male and female patients. Other respiratory, viral and bacterial, pathogens detected in samples positive for M. pneumoniae were similar in proportion to the M. pneumonia-negative population. A survey of the ICD-10 codes submitted in conjunction with the samples suggests that the current outbreak is mostly associated with upper respiratory tract infections. The present study is the first detailed report in the United States that shows an unprecedented increase in the detection of M. pneumoniae in the outpatient population during 2023. Our analysis suggests that this outbreak was not associated with any other bacterial or viral respiratory pathogen. The outbreak of this atypical pathogen was concentrated in the pediatric population in large urban areas. The 2023 outbreak could be a return of the cyclical M. pneumoniae outbreaks witnessed prior to the COVID-19 pandemic. Our study highlights the importance of performing continuous surveillance of respiratory pathogens, especially in the altered epidemiological landscape of the post-COVID world.

Recent Advances in Pharmaceutical Approaches of Antimicrobial Agents for Selective Delivery in Various Administration Routes

Globally, the increase of pathogenic bacteria with antibiotic-resistant characteristics has become a critical challenge in medical treatment. The misuse of conventional antibiotics to treat an infectious disease often results in increased resistance and a scarcity of effective antimicrobials to be used in the future against the organisms. Here, we discuss the rise of antimicrobial resistance (AMR) and the need to combat it through the discovery of new synthetic or naturally occurring antibacterial compounds, as well as insights into the application of various drug delivery approaches delivered via various routes compared to conventional delivery systems. AMR-related infectious diseases are also discussed, as is the efficiency of various delivery systems. Future considerations in developing highly effective antimicrobial delivery devices to address antibiotic resistance are also presented here, especially on the smart delivery system of antibiotics.

The molecular characteristics, diagnosis, and treatment of macrolide-resistant Mycoplasma pneumoniae in children

The purpose of this study is to review the molecular characteristics, the diagnosis, and treatment of the widespread infection of macrolide-resistant Mycoplasma pneumoniae (M. pneumoniae; MRMP) in children, thus providing a better knowledge of this infection and presenting the associated problems. Single point mutations in the V region of the 23S rRNA gene of M. pneumoniae genome are associated with macrolide resistance. P1-1, MLVA4-5-7-2, and ST3 are usually the predominated genetic types in the M. pneumoniae epidemics. The short-term two times serological IgM (or together with IgG) test in the acute stage can be used for confirmation. Combined serological testing and PCR might be a more prudent method to reduce macrolide consumption and antibiotic selective pressure in a clinical setting. Molecular methods for the detection of single-nucleotide mutations in the V region of the 23S rRNA gene can be used for the diagnosis of MRMP. The routine use of macrolide for the treatment of macrolide-sensitive Mycoplasma pneumoniae (MSMP) infections can get good effect, but the effects are limited for severe MRMP infections. Additional corticosteroids may be required for the treatment of severe MRMP infections in children in China during the era of MRMP.

Serum amyloid a, C-reactive protein, and procalcitonin levels in children with Mycoplasma pneumoniae infection

Background

Mycoplasma pneumoniae (MP) is a common pathogen of community‐acquired pneumonia in children. In the present study, serum amyloid A (SAA), C‐reactive protein (CRP), and procalcitonin (PCT) levels in children with MP infection were analyzed and the differential diagnoses of MP evaluated.

Methods

The study included 152 children with MP infection hospitalized in Tai’an Central Hospital in Shandong Province and 50 healthy children as controls. SAA, CRP, and PCT, as well as serum immunoglobulins and T lymphocyte subsets were analyzed during the acute and convalescent phases. Among the MP‐infected children, 30 cases were selected to monitor the SAA, immunoglobulins, and T lymphocyte subset levels for a week.

Results

The SAA, CRP, PCT, IgA, and IgM levels were significantly higher in the MP‐infected group than in the control group (F_(SAA) = 83.91, p < 0.05; F_(CRP) = 40.79, p < 0.05; F_(PCT) = 60.58, p < 0.05; F_(IgA) = 43.45, p < 0.05; F_(IgM) = 233.88, p < 0.05). In addition, the levels of these factors were significantly higher in the acute phase than in the convalescent phase (p < 0.05). However, significant difference was not observed in the IgG level between these two groups (p > 0.05). The CD3⁺ and CD4⁺ levels in the MP‐infected group were lower than in the control group ( F_(CD3+)= 60.58, P < 0.05; F_(CD4+) = 89.05, p < 0.05), and the CD8⁺ level was higher than in the control group ( F_(CD8+)= 96.96, p < 0.05). The CD3⁺, CD4⁺, and CD8⁺ levels were significantly different between the acute phase and the convalescent phase (CD3⁺: acute phase vs. convalescent phase, q = 2.79, p < 0.05; CD4⁺: acute phase vs. convalescent phase, q = 2.83, p < 0.05; CD8⁺: acute phase vs. convalescent phase, q = 3.15, p < 0.05). The changes in serum SAA levels in the MP‐infected group positively correlated with the changes in IgA, IgM, and CD8⁺ levels and negatively correlated with CD3⁺, CD4⁺, and CD4⁺/CD8⁺.

Conclusion

SAA, CRP, and PCT were specific markers for diagnosing early MP infection in children. These findings are important in the differential diagnosis of MP infection and clinical guidance for MP treatment.

Atypical Stevens-Johnson Syndrome Associated With Mycoplasma Pneumoniae

Mycoplasma pneumoniae primarily causes atypical pneumonia in children and young adults. 7%-8% of patients with M. pneumoniae infections may experience extra-pulmonary manifestations, including M. pneumoniae-associated Stevens-Johnson Syndrome (SJS), also known as atypical SJS. In recent literature, there have been a few reports of isolated mucositis in children with M. pneumoniae infections. Due to significant overlap with several diseases, including autoimmune disease and infections, atypical mucositis associated with M. pneumoniae is often a diagnostic challenge. In addition, due to limited cases of M. pneumoniae-associated SJS, there is no established standardized treatment guideline that has been shown to reduce hospitalization duration and/or disease progression associated with M. pneumoniae-associated SJS. We report a case of isolated mucositis in the absence of cutaneous involvement in a 10-year-old patient with an acute M. pneumoniae infection. Examination revealed erythematous ulcerations of his lips and pharynx with patchy exudates and bilateral submandibular lymphadenopathy. Laboratory investigation revealed a negative respiratory polymerase chain reaction (PCR) panel, which included M. pneumoniae. Further testing revealed a positive M. pneumoniae immunoglobulin M (IgM) titer on enzyme immunoassay. The diagnosis of atypical SJS was made secondary to M. pneumoniae. Treatment was initiated with systemic steroids and oral antibiotics. Limitations in diagnostic testing for M. pneumoniae in combination with non-specific clinical presentation make for challenges in confirming this pattern of SJS due to a primary M. pneumoniae infection. In this case, serological testing confirmed our suspected diagnosis, which guided treatment and helped reveal some of the difficulties in diagnosing and managing M. pneumoniae-associated SJS.

Association of Tandem Repeat Number Variabilities in Subunit S of the Type I Restriction-Modification System with Macrolide Resistance in Mycoplasma pneumoniae

Mycoplasma pneumoniae is one of the major pathogens responsible for pneumonia in children. Modern molecular genetics has advanced both the management and the epidemiologic study of this disease. Despite these advancements, macrolide resistance remains a global threat in the management of M. pneumoniae infection, for which the genetic background remains unrevealed. In this study, the result of whole genome analysis of 20 sequence type 3 (ST3) M. pneumoniae strains were examined to investigate the gene(s) associated with macrolide resistance. Overall, genetic similarities within M. pneumoniae, and especially ST3, were very high (over 99.99 %). Macrolide resistant ST3 strains shared 20 single nucleotide polymorphisms, of which one gene (mpn085) was found to be associated with resistance. BLAST comparison of M. pneumoniae revealed regular tandem repeat number variabilities between macrolide-susceptible and resistant strains for genes coding the Type I restriction-modification (R-M) system of subunit S (HsdS). Of the ten known HsdS genes, macrolide resistance was determined by the unique tandem repeat of mpn085 and mpn285. In conclusion, the use of whole genome sequencing (WGS) to target macrolide resistance in M. pneumoniae indicates that the determinant of macrolide resistance is variabilities in the tandem repeat numbers of the type I R-M system in subunit S.

The value of interleukin-27 for differentiating tuberculous pleural effusion from Mycoplasma pneumoniae pneumonic effusion in children

OBJECTIVES

The early diagnosis of tuberculous pleural effusion (TPE) is challenging due to the difficulty of isolating Mycobacterium tuberculosis, and pleural biomarkers are an optional choice. Recent studies showed that interleukin-27 (IL-27) appears to be a new accurate biomarker for TPE in adults and no related studies were reported in children. In this study, we aimed to evaluate the potential value of IL-27 in pediatric tuberculous pleurisy by detecting its levels in pleural fluid and serum.

METHODS

A total of 48 children with TPE and 64 children with severe Mycoplasma pneumoniae (MP) pneumonic effusion (SMPPE) were enrolled in this study. IL-27 concentrations were measured in serum and pleural fluid. The diagnostic yield of IL-27 was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

The level of p-IL-27 in TPE showed statistically no significant difference when compared with SMPPE (p > 0.05). However, pleural fluid IL-27 (p-IL-27) / serum IL-27 (s-IL-27) ratio in TPE were significantly much higher than those in SMPPE (p < 0.05). By the analysis of the ROC curves, the diagnostic sensitivity and specificity of the p-IL-27/s-IL-27 ratio were 100% and 48.44%, respectively (cutoff value of 1.0280). The area under the ROC curve for p-IL-27/s-IL-27 was 0.7295.

CONCLUSION

Pleural fluid IL-27 alone was not accurate in distinguishing pediatric TPE from SMPPE, which was different from the diagnostic value of IL-27 in adult studies due to the different disease spectra between children and adults. Our results implied that the p-IL-27/s-IL-27 ratio had a potential value in distinguishing TPE from SMPPE. However, the specificity of IL-27 was relatively lower and it is necessary to find a more specific marker in tuberculous pleurisy of children.

Effects of bronchoalveolar lavage on Mycoplasma Pneumoniae pneumonia: A propensity score matched-cohort study

BACKGROUND

The purpose of this study was to evaluate the efficacy and safety of BAL in treating MPP.

METHODS

From January 2013 to January 2019, 1,689 pediatric patients with MPP were analyzed retrospectively. Patients were subdivided into BAL group and non-BAL group according to whether they received BAL treatment within seven days after admission. The propensity score matching method matched patients' baseline characteristics (1:1). The primary outcomes were hospital stays and the cure rate. Secondary outcomes included mortality, co-infection, repeat hospitalization within 30 days, and total cost of treatment.

RESULTS

After matching, 524 patients (BAL: 262; control: 262) were recorded. The BAL group had significantly shorter hospital stays (OR: 0.5, 95% CI: 0.4-0.7). Meanwhile, BAL did not significantly modify the cost, co-infection rate, and mortality. In subgroup analyses, the group with BAL intervention within three days had a significantly shorter hospital stay (OR: 0.4, 95% CI: 0.3-0.5) compared with the group with BAL intervention three days after admission.

CONCLUSIONS

Early BAL intervention is a better treatment than conventional drug therapy alone, and no significant complications were seen in this study. BAL intervention has an excellent clinical benefit. The earlier the intervention, the better the effect.

Genotype and mutation patterns of macrolide resistance genes of Mycoplasma pneumoniae from children with pneumonia in Qingdao, China, in 2019

OBJECTIVES

This study assessed the incidence and resistance of Mycoplasma pneumoniae (MP) in children in Qingdao, China, in 2019.

METHODS

We detected MP infection in 78 pharyngeal swabs from children with pneumonia by qPCR. The RepMP4 element in the P1 adhesin gene, domain V of the 23S rRNA gene, and the L4/L22 ribosomal proteins were amplified by nested PCR. Evolutionary analysis was conducted based on the P1 gene sequence. Resistance mutations in domain V of the 23S rRNA gene and L4/L22 ribosomal proteins were analysed.

RESULTS

The incidence of MP infection in children with pneumonia was 59.0% (46/78). The mean duration of MP infection was longer than that of non-MP infection. According to P1 gene sequencing of 21 samples, 12 (57.1%) were type 1 and 9 (42.9%) were type 2. Drug resistance mutations A2063G in domain V of 23S rRNA gene and T508C in L22 were identified from all sequenced MP. However, mutations at positions 2064 and 2617 were not found in this study. C162A mutation appeared in most type 2 samples. A430G mutation appeared in one type 1 sample and in several type 2 samples. T279C mutation in L22 was mostly found in type 2 samples.

CONCLUSION

The incidence of MP infection was 59.0% in children with pneumonia in Qingdao in 2019. Type 1 MP infection was slightly more common than type 2, indicating that the genotype of MP is gradually shifting from type 1 to type 2. Macrolide resistance mutation A2063G could be detected in all sequenced MP.

Rational design of multimeric based subunit vaccine against Mycoplasma pneumonia: Subtractive proteomics with immunoinformatics framework

Mycoplasma pneumoniae is the prevalent cause of acquired respiratory infections around the globe. A multi-epitope vaccine (MEV) must be developed to combat infections of M. pneumoniae because there is no specific disease-modifying treatment or vaccination is present. The objective of this research is to design a vaccine that targets M. pneumoniae top five highly antigenic proteins using a combination of immunological techniques and molecular docking. T-cell (HTL & CTL), B-cell, and IFN-γ of target proteins were forecasted and highly conservative epitopes were chosen for further study. For designing of final vaccine, 4LBL, 7CTL, and 5HTL epitopes were joined by linkers of KK, AAY, and GPGPG. The N-end of the vaccine was linked to an adjuvant (Cholera enterotoxin subunit B) with a linker named EAAAK to enhance immunogenicity. After the addition of adjuvants and linkers, the size of the construct was 395 amino acids. The epitopes of IFN-γ and B-cells illustrate that the model construct is optimized for cell-mediated immune or humoral responses. To ensure that the final design is safer and immunogenic, properties like non-allergens, antigenicity, and various physicochemical properties were evaluated. Molecular docking of the vaccine with the toll-like receptor 4 (TLR4) was conducted to check the compatibility of the vaccine with the receptor. Besides, in-silico cloning was utilized for validation of the credibility and proper expression of the vaccine. Furthermore, to confirm that the multi-epitope vaccine created is protective and immunogenic, this research requires experimental validation.

Retrospective review analysis of COVID-19 patients co-infected with Mycoplasma pneumoniae

Introduction

Coronavirus disease 2019 (COVID-19) is an extremely infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The outbreak of this virus has resulted in significant morbidity and mortality throughout the world. We have seen an unprecedented spread of this virus, leading to extreme pressure on health-care services. Mycoplasma pneumoniae causes atypical bacterial pneumonia and is known to co-infect patients with viral pneumonias.

Methods

In this retrospective study, patients' data of 580 inpatients with confirmed SARS-CoV-2 infection were reviewed retrospectively over a 3-month period which included the the first peak of COVID-19 infections in the UK.

Results

Eight patients with COVID-19 and M. pneumoniae coinfection were identified - four males and four females. All patients were Caucasian, with an age range of 44-89 years. 37.5% of patients were hypertensive, whereas 25% had Type 2 diabetes mellitus. Dyspnea, cough, and pyrexia were found to be very common in these patients. Majority of the patients had abnormal C-reactive protein, lymphopenia, neutrophilia along with bilateral consolidation, and ground-glass opacities. Two patients required admission to intensive care, both of whom unfortunately died along with one patient receiving ward based care.

Conclusion

Our confirmed the presence of co-infection with M. pneumoniae and describes the clinical features, investigation results, clinical course, and outcomes for these patients. Further research is needed to review the role of procalcitonin in excluding bacterial co-infection and to assess the impact of co-infection of patients with COVID-19 on morbidity and mortality.

Epidemiology and mechanism of drug resistance of Mycoplasma pneumoniae in Beijing, China: A multicenter study

Mycoplasma pneumoniae (M. pneumoniae) is one of the most common causes of community-acquired respiratory tract infections (RTIs). We aimed to investigate the prevalence of M. pneumoniae infection, antibiotic resistance and genetic diversity of M. pneumoniae isolates across multiple centers in Beijing, China. P1 protein was detected by Nested PCR to analyze the occurrence of M. pneumoniae in pediatric patients with RTI. M. pneumoniae isolates were cultured and analyzed by Nested-PCR to determine their genotypes. Broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of antibiotics. Out of 822 children with RTI admitted to 11 hospitals in Beijing, 341 (41.48%) were positive for M. pneumoniae by Nested PCR and 236 (69.21%) samples had mutations in 23S rRNA domain V. The highest proportion of M. pneumoniae positive samples was observed in school-age children (118/190; 62.11%) and in pediatric patients with pneumonia (220/389; 56.56%). Out of 341 M. pneumoniae positive samples, 99 (12.04%) isolates were successfully cultured and the MIC values were determined for 65 M. pneumoniae strains. Out of these, 57 (87.69%) strains were resistant to macrolides, and all 65 strains were sensitive to tetracyclines or quinolones. M. pneumoniae P1 type I and P1 type II strains were found in 57/65 (87.69%) and 8/65 (12.31%) of cultured isolates, respectively. Overall, we demonstrated a high prevalence of M. pneumoniae infection and high macrolide resistance of M. pneumoniae strains in Beijing. School-age children were more susceptible to M. pneumoniae, particularly the children with pneumonia. Thus, establishment of a systematic surveillance program to fully understand the epidemiology of M. pneumoniae is critical for the standardized use of antibiotics in China.

Antimicrobial susceptibility and genotyping of Mycoplasma pneumoniae isolates in Beijing, China, from 2014 to 2016

Background

The presence of macrolide-resistant Myocplasma pneumoniae has been frequently reported in recent years, especially in China. In this study, we investigated the antimicrobial susceptibility and genotype against M. pneumoniae isolates from 2014 to 2016, Beijing.

Methods

We investigated the activities of four antibiotics against 81 M. pneumoniae isolates in vitro. All isolates were amplification of domains II and V of the 23S rRNA gene and the L4 and L22 ribosomal protein fragments. All isolates were genotyped with duplex real-time PCR, MLVA and VNTR detection in p1 gene.

Results

The macrolide resistance rate was 65.4% (53/81). Each of the macrolide-resistant M. pneumoniae isolates was resistant to erythromycin (Minimum Inhibitory Concentration, MIC, ≥256 μg/ml) and azithromycin (MIC, 2-64 μg/ml), but susceptible to tetracycline and levofloxacin in vitro. Fifty two macrolide-resistant isolates harbored the A2063G mutation, and only 1 macrolide-resistant isolates harbored the A2064G mutation in domain V of the 23S ribosomal RNA gene. The C162A, A430G, and T279C mutations in the L4 and L22 ribosomal protein genes were not responsible for macrolide resistance, but they were related to the particular genotype of M. pneumoniae. 95.7% of type 1 isolates (45/47) were macrolide-resistance, and 23.5% of the type 2 isolates (8/34) were macrolide-resistance. Type 2 M. pneumoniae macrolide-resistance rate was 50.6% higher than that of the previous reports in China. The eight macrolide-resistant type 2 M. pneumoniae isolates were belong to 3/5/6/2 and 3/5/7/2 MLVA genotypes.

Conclusion

To our knowledge, this phenomenon likely resulted from a combination of genotype shifting from type1 to type 2 and antibiotic selection pressure in M. pneumoniae in China in recent years. The increase of resistance in type 2 is not due to the spread of same clone. However, the relationship between genotype shifts and macrolide resistance in M. pneumoniae needs to be further verified with more extensive surveillance data.

Mycoplasma pneumoniae: A significant but underrated pathogen in paediatric community-acquired lower respiratory tract infections

Lower respiratory tract infections are considered a common cause responsible for morbidity and mortality among children, and Mycoplasma pneumoniae is identified to be responsible for up to 40 per cent of community-acquired pneumonia in children greater than five years of age. Extrapulmonary manifestations have been reported either due to spread of infection or autoimmune mechanisms. Infection by M. pneumoniae has high incidence and clinical importance but is still an underrated disease. Most widely used serologic methods are enzyme immunoassays for detection of immunoglobulin M (IgM), IgG and IgA antibodies to M. pneumoniae, though other methods such as particle agglutination assays and immunofluorescence methods are also used. Detection of M. pneumoniae by nucleic acid amplification techniques provides fast, sensitive and specific results. Utilization of polymerase chain reaction (PCR) has improved the diagnosis of M. pneumoniae infections. Besides PCR, other alternative amplification techniques include (i) nucleic acid sequence-based amplification, (ii) Qβ replicase amplification, (iii) strand displacement amplification, (iv) transcription-mediated amplification, and (v) ligase chain reaction. Macrolides are used as the first-line treatment in childhood for M. pneumoniae infections; however, emergence of macrolide-resistant M. pneumoniae is a cause of concern. Development of a safe vaccine is important that gives protective immunity and would be a major step in reducing M. pneumoniae infections.

Comparison of enzyme-linked immunosorbent assay with indirect immunofluorescence assay for the diagnosis of Mycoplasma pneumoniae infection

BACKGROUND

The study aimed to compare enzyme-linked immunosorbent assay (ELISA) with indirect immunofluorescence assay (IFA) in the diagnosis of Mycoplasma pneumoniae infection.

METHODS

From March 2016 to May 2017, 180 patients suspected with M. pneumoniae infection were enrolled. The SeroMP kit using ELISA and PNEUMOSLIDE kit using IFA were performed in parallel to detect the IgM antibodies against M. pneumoniae. Cohen's kappa statistics were used to assess the agreement between the ELISA and IFA assays, multivariate logistic regression analysis was used to evaluate risk factors for the discordance between the ELISA and IFA assays.

RESULTS

The mean age of the enrolled subjects was 46.6 ± 21.1 years. For detection of M. pneumoniae infection, the positivities of the ELISA and IFA assays were 15.6% (95% CI: 11.0%, 21.6%) and 10.0% (95% CI: 6.4%, 15.3%), respectively. The total positivity was 19.4% (95% CI: 14.3%, 25.8%). The agreement between the ELISA and IFA assays was low (κ = 0.117, P < 0.001). Variables associated with discordant results between ELISA and IFA assays in multivariate analysis were as follows: male (OR: 0.366; 95% CI: 0.149, 0.899; P < 0.05), age (>33 years old; OR: 0.313; 95% CI: 0.129, 0.758; P < 0.05).

CONCLUSION

In detection of M. pneumoniae infection, low agreement was found in IgM assays between the ELISA and IFA methods, female and younger age were significant risk factors for the discordance. A combination of ELISA and IFA tests would be recommended, in order to detect more patients suspected of M. pneumoniae infection in clinical practice.

Detection of immunoglobulin M and immunoglobulin G antibodies to Mycoplasma pneumoniae in children with community-acquired lower respiratory tract infections

Context

Mycoplasma pneumoniae (M. pneumoniae) causes up to 40% of community-acquired pneumonia in children. It is impossible to identify M. pneumoniae infection on the basis of clinical signs, symptoms, and radiological features. Therefore, correct etiological diagnosis strongly depends on laboratory diagnosis.

Aims

This study aims to investigate the role of M. pneumonia e in pediatric lower respiratory tract infections (LRTIs) employing enzyme-linked immunosorbent assays (ELISA) and particle agglutination (PA) test.

Settings and Design

Two hundred and eighty children, age 6 months to 12 years with community-acquired LRTIs were investigated for M. pneumoniae etiology.

Materials and Methods

We investigated 280 children hospitalized for community-acquired LRTIs, using ELISA and PA test for detecting M. pneumoniae immunoglobulin M (IgM) and immunoglobulin G antibodies.

Statistical Analysis Used

The difference of proportion between the qualitative variables was tested using the Chi-square test and Fischer exact test. P ≤ 0.05 was considered as statistically significant. Kappa value was used to assess agreement between ELISA and PA test.

Results

M. pneumoniae was positive in 51 (23.2%) <5 years and 33 (54.0%) children in ≥5 years of age group, and this difference was statistically significant (P < 0.001). Clinical and radiological findings in M. pneumoniae positive and negative groups were comparable. ELISA detected M. pneumoniae in 78 (27.8%) and PA test 39 (13.9%) patients; 33 (84.6%) ELISA positive and 6 (15.4%) ELISA negative. ELISA/PA test together detected M. pneumoniae infection in 84 (30%) children.

Conclusions

Our data underline that M. pneumoniae plays an important role in children with community-acquired LRTIs and more particularly in children >5 years of age.

Mechanisms and treatments for severe, steroid-resistant allergic airway disease and asthma

Severe, steroid-resistant asthma is clinically and economically important since affected individuals do not respond to mainstay corticosteroid treatments for asthma. Patients with this disease experience more frequent exacerbations of asthma, are more likely to be hospitalized, and have a poorer quality of life. Effective therapies are urgently required, however, their development has been hampered by a lack of understanding of the pathological processes that underpin disease. A major obstacle to understanding the processes that drive severe, steroid-resistant asthma is that the several endotypes of the disease have been described that are characterized by different inflammatory and immunological phenotypes. This heterogeneity makes pinpointing processes that drive disease difficult in humans. Clinical studies strongly associate specific respiratory infections with severe, steroid-resistant asthma. In this review, we discuss key findings from our studies where we describe the development of representative experimental models to improve our understanding of the links between infection and severe, steroid-resistant forms of this disease. We also discuss their use in elucidating the mechanisms, and their potential for developing effective therapeutic strategies, for severe, steroid-resistant asthma. Finally, we highlight how the immune mechanisms and therapeutic targets we have identified may be applicable to obesity-or pollution-associated asthma.

Control of a Mycoplasma pneumoniae Outbreak in an Institutional Setting Using Azithromycin Prophylaxis

Background

Mycoplasma pneumoniae is a major cause of respiratory infection of varying severity. Outbreaks of M. pneumoniae infection commonly occur in closed or semi-closed communities and settings. The control of such outbreaks is challenging, owing to delayed detection, long incubation period, and paucity of infection control guidelines.

Methods

Between May and July 2015, a residential facility for adults with developmental disabilities in Southern Israel witnessed an outbreak of acute respiratory infection, subsequently diagnosed as associated with M. pneumoniae. All relevant data were collected as a part of a formal outbreak investigation. Strict infection control procedures were implemented, and azithromycin prophylaxis was provided to all residents.

Results

Out of 215 residents, there were 29 suspected cases, 23 of which were confirmed as M. pneumoniae infection by serology or nucleic acid testing, for an attack rate of 11%. There were no cases of severe or fatal illness. An infection control strategy, including implementation of strict case isolation, enforcement of hygiene measures, a high index of suspicion for case detection, and use of azithromycin prophylaxis for all residents, led to rapid cessation of the outbreak.

Discussion

The use of azithromycin prophylaxis may be worthwhile in closed institutional settings in which M. pneumoniae infections are documented. The dynamics of this outbreak suggest that if spread between wards is anticipated, expanding prophylaxis beyond immediate contacts of affected individuals should be considered.

Molecular characterization of genomic DNA in mycoplasma pneumoniae strains isolated from serious mycoplasma pneumonia cases in 2016, Yunnan, China

Mycoplasma pneumoniae (MP) is particularly prevalent in low-immunity school-age children. Few data have been reported on MP prevalence in Yunnan, China. This study was designed to investigate the prevalence and characterize genomic DNA of MP in a small outbreak in 2016, Southwest China. RepMP4 and RepMP2/3 genes of MP positive samples were amplified for molecular typing through sequence alignment and PCR-RFLP assay. Phylogenetic trees were constructed by MEGA5.0. The results showed that two distinct P1 types (type I and type II) were prevalent in this MP outbreak. Type I was the most prevalent type, and clustered in the same evolutionary branch of C26 (China, 2012). Only 1 MP isolate belonged to type II, and clustered in the branch of KCH405 (Japan, 2016). Fifty-nine nucleotide mutations were observed in P1 genes of type I isolates (51 in RepMP4, 8 in RepMP2/3). Ninety-five nucleotide mutations were observed in P1 genes of the type II isolates (33 in RepMP4, 62 in RepMP2/3). It is noteworthy that 31 mutation sites were clustered in an 84-bp fragment in the RepMP4 gene of type II isolates. One new fragment that appeared in two of the type I strains was not found in NCBI. Nucleotide diversity analyze results showed that RepMP4 was more likely to be genetically diverse than RepMP2/3. Two-tailed Z-test result of RepMP4 suggested positive selection between 6 P1 type I isolates and M29 (China, 2005). According to secondary structure prediction, 36 new possible protein binding sites were found and another 9 sites were lost, 2 helices were missed and 1 new helix appeared in type I isolates. As for type II isolates, 16 protein binding regions were gained and 31 were lost. This study may help to understand the intrinsic geographical relatedness and contributes further to the research of MP.

Rare complicated parapneumonic effusion, Mycoplasma pneumoniae with new-onset lupus flare: Case report and literature review

Mycoplasma pneumoniae has been associated with respiratory tract infections. Mycoplasma pneumoniae pneumonia–related pleural effusion is rarely reported. Extra-pulmonary abnormalities such as encephalitis, myocarditis, glomerulonephritis, and myringitis have been reported. However pulmonary manifestations in systemic lupus erythematosus include pneumonitis, pleurisy, interstitial lung disease, and thromboembolic disease. We present the case of a 26-year-old male who came for evaluation of fever, cough, and shortness of breath with right-sided chest pain. He was found to have right-side loculated complicated parapneumonic effusion and underwent drainage with a pleural catheter followed by fibrinolytic therapy. He was then found to have new-onset systemic lupus erythematosus concomitant with Mycoplasma pneumonia, leading to lupus flare and lupus nephritis. He responded well to levofloxacin, steroids, hydroxychloroquine, and mycophenolate, with complete resolution of loculated pleural effusion and symptom improvement. Our case describes the rare combination of Mycoplasma pneumoniae pneumonia, parapneumonic pleural effusion, and lupus flare with lupus nephritis. Early identification and treatment can lead to better out come in young patients.

Atypical bacterial pneumonia in the HIV-infected population

Human immunodeficiency virus (HIV)-infected individuals are more susceptible to respiratory tract infections by other infectious agents (viruses, bacteria, parasites, and fungi) as their disease progresses to acquired immunodeficiency syndrome. Despite effective antiretroviral therapy, bacterial pneumonia (the most frequently occurring HIV-associated pulmonary illness) remains a common cause of morbidity and mortality in the HIV-infected population. Over the last few decades, studies have looked at the role of atypical bacterial pneumonia (i.e. pneumonia that causes an atypical clinical presentation or responds differently to typical therapeutics) in association with HIV infection. Due to the lack of available diagnostic strategies, the lack of consideration, and the declining immunity of the patient, HIV co-infections with atypical bacteria are currently believed to be underreported. Thus, following an extensive database search, this review aimed to highlight the current knowledge and gaps regarding atypical bacterial pneumonia in HIV. The authors discuss the prevalence of Chlamydophila pneumoniae, Mycoplasma pneumoniae, Coxiella burnetii, Legionella species and others in the HIV-infected population as well as their clinical presentation, methods of detection, and treatment. Further studies looking at the role of these microbes in association with HIV are required. Increased knowledge of these atypical bacteria will lead to a more rapid diagnosis of these infections, resulting in an improved quality of life for the HIV-infected population.

A Rare Case of Cavitary Lesion of the Lung Caused by Mycoplasma pneumoniae in an Immunocompetent Patient

Mycoplasma pneumoniae is an atypical bacterium that most commonly causes upper respiratory tract infections, but it can also cause pneumonia, referred to as "walking pneumonia." Although cavitary lesions are present in a wide variety of infectious and noninfectious processes, those attributable to M. pneumoniae are extremely uncommon; thus, to date, epidemiological studies are lacking. Here, we present a rare case of a 20-year-old male, referred to us from a psychiatric facility for evaluation of a cough, who was found to have a cavitary lesion in the right upper lobe. An extensive workup for cavitary lesion was negative, but his mycoplasma IgM level was high. A computed tomography (CT) of the chest confirmed the presence of a cavitary lesion. After treatment with levofloxacin antibiotics, a follow-up CT showed complete resolution of the lesion. Our case is a rare presentation of mycoplasma pneumonia as a cavitary lesion in a patient without any known risk factors predisposing to mycoplasma infection. Early recognition and treatment with an appropriate antibiotic may lead to complete resolution of the cavitary lesion.

Epidemiology and Molecular Characteristics of Mycoplasma pneumoniae During an Outbreak of M. pneumoniae-associated Stevens-Johnson Syndrome

BACKGROUND

An increase in Mycoplasma pneumoniae-associated Stevens-Johnson syndrome (SJS) cases at a Colorado pediatric hospital led to an outbreak investigation. We describe the epidemiologic and molecular characteristics of M. pneumoniae among SJS case-patients and surrounding community members during the outbreak.

METHODS

M. pneumoniae polymerase chain reaction-positive respiratory specimens from 5 Colorado hospitals and 4 referral laboratories underwent confirmatory polymerase chain reaction testing; positive specimens then underwent multilocus variable-number tandem-repeat analysis (MLVA) and macrolide resistance testing. Three SJS-M. pneumoniae case-patient households were surveyed using a standardized questionnaire, and nasopharyngeal/oropharyngeal swabs were obtained from all consenting/assenting household contacts. International Classification of Diseases, 9th revision codes were used to identify pneumonia cases among Colorado patients 5-21 years of age from January 2009 to March 2014.

RESULTS

Three different M. pneumoniae MLVA types were identified among the 5 SJS case-patients with confirmed infection; MLVA type 3-X-6-2 was seen more commonly in SJS case-patients (60%) than in 69 non-SJS community specimens (29%). Macrolide resistance was identified in 7% of community specimens but not among SJS case-patients. Of 15 household contacts, 5 (33%) were M. pneumoniae positive; all MLVA types were identical to those of the corresponding SJS case-patient, although the specimen from 1 contact was macrolide resistant. Overall pneumonia cases as well as those caused by M. pneumoniae specifically peaked in October 2013, coinciding with the SJS outbreak.

CONCLUSIONS

The outbreak of M. pneumoniae-associated SJS may have been associated with a community outbreak of M. pneumoniae; clinicians should be aware of the M. pneumoniae-SJS relationship. Household transmission of M. pneumoniae was common within the households investigated.

Pulmonary Infections

Pneumonia is a lung infection involving the alveoli and can be caused by a variety of microbes including bacteria, viruses, and fungi. It is the leading infectious cause of hospitalization and death in the United States [1]. In 2010, in the United States, pneumonia resulted in 1.1 million discharges from the hospital with an average length of stay of 5.2 days. Pneumonia accounted for 3.4 % of hospital deaths in 2006. In 2013 it accounted for 16.9 deaths per 100,000 population [2]. Pneumonia continues to be the leading killer of young children around the world, causing 14 % of all deaths in children ages 1 month to 5 years [3].

Acute respiratory distress syndrome related to Mycoplasma pneumoniae infection

M. pneumoniae respiratory infection is usually mild and self-limiting. We report a case of acute respiratory distress syndrome (ARDS) due to M. pneumoniae infection in a 60 years old woman. Quick diagnosis was established by multiplex PCR assay for detection of pneumonia-causing bacteria. Outcome was favorable. The factors accounting for the severity of pneumonia caused by M. pneumoniae are discussed.

Pathogenesis of Mycoplasma pneumoniae: An update

Genus Mycoplasma, belonging to the class Mollicutes, encompasses unique lifeforms comprising of a small genome of 8,00,000 base pairs and the inability to produce a cell wall under any circumstances. Mycoplasma pneumoniae is the most common pathogenic species infecting humans. It is an atypical respiratory bacteria causing community acquired pneumonia (CAP) in children and adults of all ages. Although atypical pneumonia caused by M. pneumoniae can be managed in outpatient settings, complications affecting multiple organ systems can lead to hospitalization in vulnerable population. M. pneumoniae infection has also been associated with chronic lung disease and bronchial asthma. With the advent of molecular methods of diagnosis and genetic, immunological and ultrastructural assays that study infectious disease pathogenesis at subcellular level, newer virulence factors of M. pneumoniae have been recognized by researchers. Structure of the attachment organelle of the organism, that mediates the crucial initial step of cytadherence to respiratory tract epithelium through complex interaction between different adhesins and accessory adhesion proteins, has been decoded. Several subsequent virulence mechanisms like intracellular localization, direct cytotoxicity and activation of the inflammatory cascade through toll-like receptors (TLRs) leading to inflammatory cytokine mediated tissue injury, have also been demonstrated to play an essential role in pathogenesis. The most significant update in the knowledge of pathogenesis has been the discovery of Community-Acquired Respiratory Distress Syndrome toxin (CARDS toxin) of M. pneumoniae and its ability of adenosine diphosphate (ADP) ribosylation and inflammosome activation, thus initiating airway inflammation. Advances have also been made in terms of the different pathways behind the genesis of extrapulmonary complications. This article aims to comprehensively review the recent advances in the knowledge of pathogenesis of this organism, that had remained elusive during the era of serological diagnosis. Elucidation of virulence mechanisms of M. pneumoniae will help researchers to design effective vaccine candidates and newer therapeutic targets against this agent.

Community-Acquired Pneumonia Caused by Mycoplasma pneumoniae: How Physical and Radiological Examination Contribute to Successful Diagnosis

Mycoplasma pneumoniae is one of the most common causes of community-acquired pneumonia (CAP), particularly in young adults. Vital signs are usually normal except for temperature. On physical examination, general appearance is normal compared with that of typical pneumonia such as pneumococcal pneumonia patients. Mycoplasma sometimes causes ear infections such as otitis media. It is important to distinguish between typical pneumonia and atypical pneumonia such as mycoplasma pneumonia because having the right diagnosis allows for the use of the correct antibiotic to treat CAP while preventing development of drug-resistant bacteria and also decreasing medical cost. The symptoms and diagnosis of mycoplasma pneumonia is multi-fold. Auscultation of patients can demonstrate trace late inspiratory crackles or normal alveolar sounds; however, bilateral polyphonic wheezes can sometimes be heard because of bronchiolitis. With regard to radiological findings, a chest radiogragh often shows bilateral reticulonodular or patchy consolidation in both lower lobes. Pleural effusion is rarely observed in adult cases. Immunocompetent patients tend to reveal more extensive shadowing compared with immunocompromised patients. As serological diagnostic methods are not able to offer 100% reliable diagnosis, integration of physical and radiological examination is crucial to accurately diagnose mycoplasma pneumonia. Herein, I review the typical findings from physical examination and imaging patterns of patients with mycoplasma pneumonia.

Prevalence, genotyping and macrolide resistance of Mycoplasma pneumoniae among isolates of patients with respiratory tract infections, Central Slovenia, 2006 to 2014

In this retrospective study we employed real-time polymerase chain reaction (PCR) to analyse the occurrence of Mycoplasma pneumoniae among upper and lower respiratory tract infections (RTI) in the Central Region of Slovenia between January 2006 and December 2014. We also used a culture and pyrosequencing approach to genotype strains and infer their potential macrolide resistance. Of a total 9,431 tested samples from in- and out-patient with RTI, 1,255 (13%) were found to be positive by M. pneumoniae PCR. The proportion of positive samples was 19% (947/5,092)among children (≤16 years-old) and 7% (308/4,339) among adults (>16 years-old). Overall, among those PCR tested, the highest proportions of M. pneumonia infections during the study period were observed in 2010 and 2014. In these two years, 18% (218/1,237) and 25% (721/2,844) of samples were positive respectively,indicating epidemic periods. From the 1,255 M. pneumoniae PCR-positive samples, 783 (614 from paediatric and 169 from adult patients) were successfully cultured. Of these, 40% (312/783) were constituted of strains belonging to the P1 type II genomic group, while 60% (469/783) contained strains of the P1 type I group. Two isolates comprised both P1 type Iand II strains. Results of a genotype analysis by year,showed that the dominant M. pneumoniae P1 type during the 2010 epidemic was P1 type II (82% of isolates;81/99), which was replaced by P1 type I in the 2014 epidemic (75%; 384/510). This observation could indicate that the two epidemics may have been driven by a type shift phenomenon, although both types remained present in the studied population during the assessed period of time. Only 1% of strains (7/783) were found to harbour an A2063G mutation in the 23S rRNA gene,which confers macrolide resistance, suggesting that the occurrence of M. pneumoniae macrolide resistance still seems to be sporadic in our geographic area.

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.

Rare extrapulmonary complications of Mycoplasma pneumoniae infection

Stevens-Johnsons syndrome (SJS) is a rare extra-pulmonary complication of Mycoplasma pneumoniae infection. We present the case of a 26-year-old man with fever, cough, extensive oral mucosal ulceration and a widespread truncal rash. He was diagnosed with M. pneumoniae-induced SJS. He responded well to antibiotics and steroids initially, but went on to develop pseudomembranous conjunctivitis requiring bilateral amniotic membrane grafting. SJS is most commonly drug-induced, however, M. pneumoniae is the commonest infectious cause and should be considered in the differential diagnosis. It is also important to get specialist care involved early to minimise the long-term effects of any complications.

Retraction: Pneumonia in Vietnamese Children Aged 1 to 15 years Due to Atypical Pneumonia Causative Bacteria: Hospital-Based Microbiological and Epidemiological Characteristics

This article has been retracted by the authors under the agreement between the Editor-in-Chief, Masayuki Saijo and authors.

First report on prevalence and risk factors of severe atypical pneumonia in Vietnamese children aged 1-15 years

Background

Atypical pathogens such as Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila are increasingly recognized as important causes of community acquired pneumonia (CAP) worldwide. Such etiological data for Vietnam is scarce and clinical doctors lack accurate information on which to base their diagnosis and treatment of pneumonia. This study identifies the prevalence and risk factors of severe community acquired pneumonia due to these atypical pathogens (severe-ApCAP) in children aged 1–15 years with CAP in a pediatric hospital in Hanoi, Vietnam.

Methods

722 hospitalized children with CAP were recruited for detecting those atypical pathogens, using multiplex PCR and ELISA. Clinical and epidemiological data were collected. Multivariate logistic-regression analyses were performed to evaluate the associations of potential risk factors with severe-ApCAP.

Results

Among 215 atypical pathogen-positive CAP cases, 45.12% (97/215) were severe-ApCAP. Among the severe-ApCAP group, 55.67% (54/97) cases were caused by pure atypical pathogens and 44.33% (43/97) resulted from a co-infection with typical respiratory pathogens. M. pneumoniae was the most common, with 86.6% cases (84/97) in the severe-ApCAP group, whereas C. pneumoniae and L. pneumophila were less frequent (6.19% and 7.22%, respectively). The highest rate of severe-ApCAP was in children younger than two years (65.98%). The differences related to age are statistically significant (P = 0.008).

The factors significantly associated with severe-ApCAP were age (OR = 0.84, 95% CI = 0.75-0.93, P = 0.001), co-infection with typical bacteria (OR = 4.86, 95% CI = 2.17-10.9, P < 0.0001), co-infection with respiratory viruses (OR = 4.36, 95% CI = 1.46-13.0, P = 0.008), respiratory/cardiac system malformation (OR = 14.8, 95% CI = 1.12 -196, P = 0.041) and neonatal pneumonia (OR = 11.1, 95% CI = 1.06 -116, P = 0.044).

Conclusions

Severe-ApCAP presented at a significant rate in Vietnamese children. More than 50% of severe-ApCAP cases were associated with pure atypical pathogen infection. M. pneumoniae appeared most frequently. The highest rate of severe-ApCAP was in children younger than two years. Younger age and co-infection with typical bacteria or viruses were the most significant risk factors, while respiratory/cardiac system malformation and neonatal pneumonia were additional potential risk factors, associated with severe-ApCAP in Vietnamese children.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2458-14-1304) contains supplementary material, which is available to authorized users.

Molecular characterizations of PCR-positive Mycoplasma pneumoniae specimens collected from Australia and China

Mycoplasma pneumoniae is an important cause of community-acquired pneumonia (CAP). In this study, M. pneumoniae strains in PCR-positive specimens collected from patients in Sydney, Australia (30 samples), and Beijing, China (83 samples), were characterized using multilocus variable-number tandem-repeat (VNTR) analysis (MLVA), P1-restriction fragment length polymorphism (RFLP) analysis, and sequencing of domain V of the 23S rRNA gene to compare genotype distribution and macrolide resistance rates between locations. Eighteen distinct MLVA types were identified in specimens from Sydney, of which 10 were known (types E, G, J, M, N, P, U, V, S, and X) and 8 previously unknown. Strains were equally distributed between P1-RFLP type 1 and type 2 variants. Among samples from Beijing, MLVA types E, G, J, P, U, X, and Z and four new types were identified. Most specimens belonged to P1-RFLP type 1. A nomenclature based on five VNTR loci is proposed to designate MLVA patterns. Macrolide resistance-associated mutations were identified in only 1 of 30 specimens (3.3%) from Sydney and 71 of 83 (85.5%) from Beijing (P<0.05). This study demonstrated that although multiple individual M. pneumoniae strains were circulating in Beijing, the genotypes were less diverse than those in Sydney. However, the greatest regional difference was in the incidence of macrolide resistance, which may reflect differences in antibiotic use and/or measures in resistance control.

Clinical features, risk factors and treatment of fulminant Mycoplasma pneumoniae pneumonia: a review of the Japanese literature

Mycoplasma pneumoniae (MP) is one of the most common causes of community-acquired pneumonia in children and young adults. Although MP sometimes causes self-limiting pneumonia, severe and fulminant cases with hypoxia occur, but their clinical features have rarely been reported. This study aimed to reveal the clinical manifestations, risk factors, and treatment of fulminant MP pneumonia (MPP). Using PubMed and abstracts from the proceedings of several domestic Japanese academic societies, we reviewed the Japanese and English literature for cases of fulminant or severe MPP reported in Japan. All clinical information such as sex, age, underlying diseases, clinical symptoms, clinical course, laboratory and radiological findings, and treatment was collected and analyzed. In total, 52 fulminant MPP cases were reported between September, 1979 and February, 2010. The dominant population of fulminant MPP was young adults without severe underlying diseases. Cough (97.3%), fever (100.0%), and dyspnea (83.3%) with diffuse abnormal findings in radiological examinations were noted. Antibiotics without anti-mycoplasmal activity were used in 32 cases (61.5%) as initial treatment prior to the onset of hypoxia. Anti-mycoplasmal drugs were appropriately used in 41 cases (78.8%) after onset of respiratory failure with steroids (23 cases, 45.1%) and effective. The majority of patients improved within 3-5 days after steroid administration. There were only 2 fatal cases. Although this small retrospective study did not reveal the apparent risk factors of fulminant MPP, initial inappropriate use of antibiotics may be a risk factor, and early administration of appropriate anti-mycoplasmal drugs with steroids as a cellular immune suppressor is required.

AcuteChlamydia pneumoniaeandMycoplasma pneumoniaeInfections in Community-Acquired Pneumonia and Exacerbations of COPD or Asthma: Therapeutic Considerations

Rates of acute Chlamydia pneumoniae and Mycoplasma pneumoniae infections were determined in 115 adults hospitalized for community-acquired pneumonia (CAP), purulent exacerbations of COPD and acute exacerbations of bronchial asthma, by means of serology and molecular methods. Results were compared with those obtained in a matched control group. Common respiratory pathogens were isolated by cultures in 22.5% and 22.2% of CAP and exacerbated COPD patients, respectively. Cultures from exacerbated asthma patients were always negative. Serological and molecular evidence of current C. pneumoniae infection was obtained in 10.0%, 8.9% and 3.3% of CAP, COPD and asthma cases. The corresponding rates of acute M. pneumoniae infection were 17.5%, 6.7% and 3.3%, respectively. Finally, no difference was found between typical and atypical pathogen rates. These findings highlight the importance of taking into account C. pneumoniae and M. pneumoniae infections in guiding the choice of empirical antibacterial treatment for CAP and purulent exacerbations of COPD.

Detection of Mycoplasma pneumoniae by colorimetric loop-mediated isothermal amplification

Mycoplasma pneumoniae (M. pneumoniae) is one of the most important pathogens that cause respiratory tract infection in children and adults. In this study, we describe a rapid and sensitive colorimetric loop mediated isothermal amplification (LAMP) method to detect M. pneumoniae. The specificity and sensitivity of this assay were detected with 21 common respiratory pathogens and 39 M. pneumoniae DNA. The sensitivity of LAMP was 100% among 39 M. pneumoniae isolates and the specificity was 100% among 9 members of other Mycoplasma and 12 common respiratory pathogens. The lowest detectable limit (LDL) of this assay was 102 copies, which detected by a series of standard M. pneumoniae DNA. To evaluate the clinical applicability of the LAMP assay, a total of 80 clinical samples were examined by conventional PCR, real-time PCR and the LAMP assays, respectively. The positive rates were 15.0%, 32.5% and 26.3%, respectively. This colorimetric LAMP assay demonstrated a high level of sensitivity comparable with that of conventional PCR for the detection of M. pneumoniae. It is a valuable method for simple, cost-effective and rapid detection of M. pneumoniae in the rural areas and basic clinical of China.

Mycoplasma pneumoniae with atypical stevens-johnson syndrome: a diagnostic challenge

The Stevens-Johnson syndrome (SJS) classically involves a targetoid skin rash and the association of the oral mucosa, genitals, and conjunctivae. Recently, there have been several documentations of an incomplete presentation of this syndrome, without the typical rash, usually associated with the mycoplasma pneumoniae infection. Our case illustrates that this important clinical diagnosis should not be missed due to its atypical presentation.

Detection of Mycoplasma pneumoniae by real-time PCR

Mycoplasma pneumoniae is a significant cause of respiratory disease, accounting for approximately 20% of cases of community-acquired pneumonia. Although several diagnostic methods exist to detect M. pneumoniae in respiratory specimens, real-time PCR has emerged as a significant improvement for the rapid diagnosis of this pathogen. The method described herein details the procedure for the detection of M. pneumoniae by real-time PCR (qPCR). The qPCR assay described can be performed with three targets specific for M. pneumoniae (Mp181, Mp3, and Mp7) and one marker for the detection of the RNaseP gene found in human nucleic acid as an internal control reaction. Recent studies have demonstrated the ability of this procedure to reliably identify this agent and facilitate the timely recognition of an outbreak.

Surveillance of macrolide-resistant Mycoplasma pneumoniae in Beijing, China, from 2008 to 2012

Macrolide resistance rates of Mycoplasma pneumoniae in the Beijing population were as high as 68.9%, 90.0%, 98.4%, 95.4%, and 97.0% in the years 2008 to 2012, respectively. Common macrolide-resistant mobile genetic elements were not detected with any isolate. These macrolide-resistant isolates came from multiple clones rather than the same clone. No massive aggregation of a particular clone was found in a specific period.