Macrolide-resistant Mycoplasma pneumoniae: its role in respiratory infection

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.

Efficacy of doxycycline therapy for macrolide-resistant Mycoplasma pneumoniae pneumonia in children at different periods

BACKGROUND

The prevalence of macrolide-resistant Mycoplasma pneumoniae has increased considerably. Treatment in children has become challenging. This study aimed to evaluate the efficacy of doxycycline therapy for macrolide-resistant Mycoplasma pneumoniae pneumonia in children at different periods.

METHODS

We retrospectively analyzed the data of patients with macrolide-resistant Mycoplasma pneumoniae pneumonia hospitalized between May 2019 to August 2022. According to treatment, patients were divided into three groups: oral doxycycline treatment alone (DOX group), changed from intravenous azithromycin to oral doxycycline (ATD group), and intravenous azithromycin treatment alone (AZI group). ATD group cases were separated into two sub-groups: intravenous azithromycin treatment<3 days (ATD1 group) and ≥ 3 days (ATD2 group). Clinical symptoms were compared in each group and adjusted by Propensity score matching (PSM) analysis.

RESULTS

A total of 106 were recruited in this study. 17 (16%) were in DOX group, 58 (55%) in ATD group, and 31(29%) in AZI group. Compared with ATD group and AZI group, the DOX group showed shorter hospitalization duration and fever duration after treatment, while higher rate of chest radiographic improvement. After using PSM analysis, shorter days to hospitalization duration (P = 0.037) and to fever duration after treatment (P = 0.027) in DOX + ATD1 group than in ATD2 group was observed. A higher number of patients in the DOX + ATD1 group achieved defervescence within 72 h (P = 0.031), and fewer children received glucocorticoid adjuvant therapy (P = 0.002). No adverse reactions associated with doxycycline was observed during treatment.

CONCLUSIONS

Children receiving early oral doxycycline had a shorter duration of fever and hospitalization in macrolide-resistant Mycoplasma pneumoniae patients.

Molecular epidemiology of Mycoplasma pneumoniae pneumonia in children, Wuhan, 2020-2022

BACKGROUND

Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen of community-acquired pneumonia in children. The factors contributing to the severity of illness caused by M. pneumoniae infection are still under investigation. We aimed to evaluate the sensitivity of common M. pneumoniae detection methods, as well as to analyze the clinical manifestations, genotypes, macrolide resistance, respiratory microenvironment, and their relationship with the severity of illness in children with M. pneumoniae pneumonia in Wuhan.

RESULTS

Among 1,259 clinical samples, 461 samples were positive for M. pneumoniae via quantitative polymerase chain reaction (qPCR). Furthermore, we found that while serological testing is not highly sensitive in detecting M. pneumoniae infection, but it may serve as an indicator for predicting severe cases. We successfully identified the adhesin P1 (P1) genotypes of 127 samples based on metagenomic and Sanger sequencing, with P1-type 1 (113/127, 88.98%) being the dominant genotype. No significant difference in pathogenicity was observed among different genotypes. The macrolide resistance rate of M. pneumoniae isolates was 96% (48/50) and all mutations were A2063G in domain V of 23S rRNA gene. There was no significant difference between the upper respiratory microbiome of patients with mild and severe symptoms.

CONCLUSIONS

During the period of this study, the main circulating M. pneumoniae was P1-type 1, with a resistance rate of 96%. Key findings include the efficacy of qPCR in detecting M. pneumoniae, the potential of IgM titers exceeding 1:160 as indicators for illness severity, and the lack of a direct correlation between disease severity and genotypic characteristics or respiratory microenvironment. This study is the first to characterize the epidemic and genomic features of M. pneumoniae in Wuhan after the COVID-19 outbreak in 2020, which provides a scientific data basis for monitoring and infection prevention and control of M. pneumoniae in the post-pandemic era.

Clinical, Laboratory, and Radiographic Features Can Help Predict Mycoplasma pneumoniae Lower Respiratory Tract Infection in Children

Mycoplasma pneumoniae (Mp) is a common cause of lower respiratory tract infection (LRTI) in children that is difficult to distinguish from LRTI of other etiologies. We aimed to determine if a combination of clinical, laboratory, and chest radiographic features can help identify patients at higher risk of Mp LRTI. We reviewed medical charts of children referred to our tertiary hospital with suspected acute mycoplasmal LRTI. Pharyngeal swabs obtained from patients were tested by Mp PCR. We compared epidemiological and clinical data of children with positive and negative Mp PCR results. In addition, a multivariable logistic regression analysis was performed to predict Mp LRTI based on the patient's age, duration of symptoms, presence of extrapulmonary manifestations, laboratory findings, and chest radiographic findings. We included 65 children with Mp PCR-negative and 49 with Mp PCR-positive LRTI and no viral co-detection. Children with Mp LRTI were older (median age 5.8 vs. 2.2 years, p < 0.001), had a longer duration of symptoms on referral (median 7 vs. 4 days, p < 0.001), and lower median WBC (9.9 vs. 12.7 × 10⁹/L, p < 0.001). On chest radiograph, unilateral infiltrates were more frequently observed in the Mp PCR-positive group (57.5% vs. 24.1%, p = 0.001). Age, duration of symptoms, and chest radiographic findings had the highest predictive value for Mp LRTI in a multivariable logistic regression model. Our analysis suggests that a combination of clinical, laboratory, and chest radiographic features can be used to assess the likelihood of Mp LRTI and assist in decision-making for which children need further tests or macrolide antibiotic treatment.

The clinical significance of macrolide resistance in pediatric Mycoplasma pneumoniae infection during COVID-19 pandemic

Background

Mycoplasma pneumoniae (MP) is a commonly occurring pathogen causing community-acquired pneumonia (CAP) in children. The global prevalence of macrolide-resistant MP (MRMP) infection, especially in Asian regions, is increasing rapidly. However, the prevalence of MRMP and its clinical significance during the COVID-19 pandemic is not clear.

Methods

This study enrolled children with molecularly confirmed macrolide-susceptible MP (MSMP) and MRMP CAP from Beijing Children's Hospital Baoding Hospital, Capital Medical University between August 2021 and July 2022. The clinical characteristics, laboratory findings, chest imaging presentations, and strain genotypes were compared between patients with MSMP and MRMP CAP.

Results

A total of 520 hospitalized children with MP-CAP were enrolled in the study, with a macrolide resistance rate of 92.7%. Patients with MRMP infection exhibited more severe clinical manifestations (such as dyspnea and pleural effusion) and had a longer hospital stay than the MSMP group. Furthermore, abnormal blood test results (including increased LDH and D-dimer) were more common in the MRMP group (P<0.05). Multilocus variable-number tandem-repeat analysis (MLVA) was performed on 304 samples based on four loci (Mpn13-16), and M3562 and M4572 were the major types, accounting for 74.0% and 16.8% of the strains, respectively. The macrolide resistance rate of M3562 strains was up to 95.1%.

Conclusion

The prevalence of MRMP strains in hospitalized CAP patients was extremely high in the Baoding area, and patients infected with MRMP strains exhibited more severe clinical features and increased LDH and D-dimer. M3562 was the predominant resistant clone.

The clinical significance of and the factors associated with macrolide resistance and poor macrolide response in pediatric Mycoplasma pneumoniae infection: A retrospective study

BACKGROUND

Macrolide-resistant Mycoplasma pneumoniae (MRMP) infection is increasing worldwide. However, its clinical significance is still uncertain.

METHODS

The data of the Laboratory Medicine Department of Chang Gung Memorial Hospital in northern Taiwan was searched for children with molecular confirmed macrolide-susceptible Mycoplasma pneumoniae (MSMP) and MRMP infections between January 2011 and December 2018. The clinical features, laboratory data, and chest image presentations were compared between patients with MRMP and MSMP infections and between patients with good and poor macrolide response, respectively.

RESULTS

Records from 158 patients were recovered. Of the enrolled patients 34 (22%) suffered MRMP infection, 27 (17%) had pleural effusions, and 47 (32%) had poor macrolide response. The macrolide resistance rate was 12% in 2011, 20% between 2015 and 2016, and 50% between 2017 and 2018, respectively. Other than a poor macrolide response, the MRMP and MSMP infections are clinically indistinguishable. The presence of pleural effusion and MRMP infections were found to be independently associated with a poor macrolide response, with odds ratios (95% confidence interval) of 14.3 (4.9-42.0) and 14.6 (5.4-40), respectively. The macrolide resistance rate of the patients with a poor macrolide response was 49% and 18% among all the patients enrolled and the patients with a pleural effusion, respectively.

CONCLUSION

The macrolide resistance rate had possibly increased in recent years in Taiwan and should be continuously monitored. In addition, the macrolide response could be misleading in predicting a macrolide resistance especially for the patients with a pleural effusion.

Course of Lower Respiratory Tract Infection in Young People Treated at the Military Hospital of Smolensk Garrison with Detected Mycoplasma pneumoniae Carrying a Macrolide-Resistant Mutation in 23S rRNA Gene

We evaluated the effect of macrolide-resistant mutations in the Mycoplasma pneumoniae 23S rRNA gene on the severity of lower respiratory tract infections in immunocompetent young adults treated at the Smolensk Military Hospital between 25 October 2017, and 17 November 2021. All analyzed cases represented a non-severe infection of the lower respiratory tract: 44 case histories with community-acquired pneumonia and 20 cases with acute bronchitis. The presence of mutations in the gene 23S rRNA of M. pneumoniae was determined with standard Sanger sequencing. The macrolide-resistant genotype was found in 4/44 (9.1%) of the samples of the patients with pneumonia and in 3/20 (15%) of the samples of the patients with acute bronchitis. The analyzed cases with identified M. pneumoniae carrying a mutation in the 23S rRNA gene did not show any differences in the clinical presentation in terms of disease severity caused by M. pneumoniae with the wild-type (WT) phenotype.

The remaining unsolved problems for rational antibiotic therapy use in pediatric community-acquired pneumonia

INTRODUCTION

Despite availability of several official guidelines, not all the problems related to the most effective and safe use of antibiotics in children with community-acquired pneumonia (CAP) have been solved. Presently, too many children receive unneeded antibiotics or, when antibiotics are mandatory, the choice of the drug is not appropriate.

AREAS COVERED

In this paper, the authors discuss the remaining unsolved problems for rational antibiotic therapy use in pediatric community-acquired pneumonia and provide their expert perspectives.

EXPERT OPINION

Further improvement in pediatric CAP management could be derived from physician education on antibiotic use and a larger use, particularly in office practice, of point of care testing or new technologies (i.e. artificial intelligence) to define etiology of a lower respiratory infection. However, recommendations regarding the duration of antibiotic therapy vary largely because of the absence of reliable data on the optimal CAP treatment according to the bacterial etiology of the disease, its severity, and child characteristics. Available evidence seems to confirm that a short course of antibiotics, approximately 5 days, can be effective and lead to results not substantially different from those obtained with prolonged-course antibiotic therapy, at least in patients with mild to moderate disease.

Molecular features and antimicrobial susceptibility of Mycoplasma pneumoniae isolates from pediatric inpatients in Weihai, China

OBJECTIVES

We analyzed the molecular features and antimicrobial susceptibility of Mycoplasma pneumoniae isolates from Weihai in 2019.

METHODS

Pharyngeal swabs of 160 pediatric patients with pneumonia-related symptoms were collected and subjected to culture and subsequent characteristic analysis. The characteristics of M. pneumoniae isolates were analyzed through real-time PCR and genotyping. Antimicrobial susceptibility test was performed against 4 antibiotics. All isolates were amplified for the analysis of macrolide (ML) resistant gene of the 23S rRNA and were genotyped with multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) and 'AGT' VNTR detection in p1 gene.

RESULTS

M. pneumoniae nucleic acid and culture positive rate of 160 specimens were 87.6% and 51.3%, respectively. Almost all isolates were ML resistant (81/82). Point mutation at 2063 site in 23S rRNA was identified in all ML resistant isolates. ML resistance rate of genotype 2 isolates was 97.6% in the M. pneumoniae isolates in Weihai. MLVA types 4/5/7/2 and 4/5/7/3 belonged to genotype 1, while 3/5/6/2 belonged to genotype 2. Numbers of 'AGT' VNTR in p1 gene from all isolates was in a range of 5-15.

CONCLUSIONS

This is the first report that the two genotypes of M. pneumoniae isolates were presented in relative equivalent ratio, with genotype 2 slightly dominant, in pediatric patients in Weihai in 2019, and the overall ML resistance rate was close to 100%. Minimum inhibitory concentration (MIC) of erythromycin in A2063T ML resistance in M. pneumoniae in Weihai was higher than previous publications.

Lefamulin in Patients with Community-Acquired Bacterial Pneumonia Caused by Atypical Respiratory Pathogens: Pooled Results from Two Phase 3 Trials

Lefamulin was the first systemic pleuromutilin antibiotic approved for intravenous and oral use in adults with community-acquired bacterial pneumonia based on two phase 3 trials (Lefamulin Evaluation Against Pneumonia [LEAP]-1 and LEAP-2). This pooled analysis evaluated lefamulin efficacy and safety in adults with community-acquired bacterial pneumonia caused by atypical pathogens (Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia pneumoniae). In LEAP-1, participants received intravenous lefamulin 150 mg every 12 h for 5–7 days or moxifloxacin 400 mg every 24 h for 7 days, with optional intravenous-to-oral switch. In LEAP-2, participants received oral lefamulin 600 mg every 12 h for 5 days or moxifloxacin 400 mg every 24 h for 7 days. Primary outcomes were early clinical response at 96 ± 24 h after first dose and investigator assessment of clinical response at test of cure (5–10 days after last dose). Atypical pathogens were identified in 25.0% (91/364) of lefamulin-treated patients and 25.2% (87/345) of moxifloxacin-treated patients; most were identified by ≥1 standard diagnostic modality (M. pneumoniae 71.2% [52/73]; L. pneumophila 96.9% [63/65]; C. pneumoniae 79.3% [46/58]); the most common standard diagnostic modality was serology. In terms of disease severity, more than 90% of patients had CURB-65 (confusion of new onset, blood urea nitrogen > 19 mg/dL, respiratory rate ≥ 30 breaths/min, blood pressure <90 mm Hg systolic or ≤60 mm Hg diastolic, and age ≥ 65 years) scores of 0–2; approximately 50% of patients had PORT (Pneumonia Outcomes Research Team) risk class of III, and the remaining patients were more likely to have PORT risk class of II or IV versus V. In patients with atypical pathogens, early clinical response (lefamulin 84.4–96.6%; moxifloxacin 90.3–96.8%) and investigator assessment of clinical response at test of cure (lefamulin 74.1–89.7%; moxifloxacin 74.2–97.1%) were high and similar between arms. Treatment-emergent adverse event rates were similar in the lefamulin (34.1% [31/91]) and moxifloxacin (32.2% [28/87]) groups. Limitations to this analysis include its post hoc nature, the small numbers of patients infected with atypical pathogens, the possibility of PCR-based diagnostic methods to identify non-etiologically relevant pathogens, and the possibility that these findings may not be generalizable to all patients. Lefamulin as short-course empiric monotherapy, including 5-day oral therapy, was well tolerated in adults with community-acquired bacterial pneumonia and demonstrated high clinical response rates against atypical pathogens.

Clinical features and risk factors analysis of bronchitis obliterans due to refractory Mycoplasma pneumoniae pneumonia in children: a nomogram prediction model

Background

Early prediction of bronchitis obliterans (BO) is of great significance to the improvement of the long-term prognosis of children caused by refractory Mycoplasma pneumoniae pneumonia (RMPP). This study aimed to establish a nomogram model to predict the risk of BO in children due to RMPP.

Methods

A retrospective observation was conducted to study the clinical data of children with RMPP (1–14 years old) during acute infection. According to whether there is BO observed in the bronchoscope, children were divided into BO and the non-BO groups. The multivariate logistic regression model was used to construct the nomogram model.

Results

One hundred and forty-one children with RMPP were finally included, of which 65 (46.0%) children with RMPP were complicated by BO. According to the multivariate logistic regression analysis, WBC count, ALB level, consolidation range exceeding 2/3 of lung lobes, timing of macrolides, glucocorticoids or fiber bronchoscopy and plastic bronchitis were independent influencing factors for the occurrence of BO and were incorporated into the nomogram. The area under the receiver operating characteristic curve (AUC-ROC) value of nomogram was 0.899 (95% confidence interval [CI] 0.848–0.950). The Hosmer–Lemeshow test showed good calibration of the nomogram (p = 0.692).

Conclusion

A nomogram model found by seven risk factor was successfully constructed and can use to early prediction of children with BO due to RMPP.

Update on the Epidemiology of Macrolide-Resistant Mycoplasma pneumoniae in Europe: A Systematic Review

Macrolide-resistant Mycoplasma pneumoniae (MR-MP) infections cause upper and lower respiratory tract infections in both children and adults, and are characterized by a longer duration of symptoms. Here, we undertook a systematic review of studies on MR-MP in Europe. The review meets PRISMA guidelines. The PubMed, Scopus, and Science Direct databases were searched using suitable keywords to identify relevant studies published from 2010 to 2021; 21 studies were included. Overall, a low level of MR-MP spread was reported in Europe. MR-MP spread increased during epidemic waves registered in Europe, particularly in Italy and Scotland, where the highest MR-MP infection rates were registered during the 2010–2011 epidemic. By contrast, no MR-MP infections were reported in Finland and the Netherlands. Continued monitoring of MR-MP in Europe is needed to maintain the low rates of infection. Moreover, a coordinated and structured pan-European surveillance program adequate for public health surveillance is advisable, with the purpose of containing the spread of antimicrobial resistance.

Consideration in treatment decisions for refractory Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae (MP) is the most common cause of childhood bacterial pneumonia. Although macrolide is known to be effective as a first-line therapy, the proportion of macrolide resistance in MP pneumonia has strikingly increased during recent 2 decades in East Asia. This is challenging to physicians since they have to decide more often whether to use secondary treatment. Diagnostic methods to detect macrolide-resistance of MP are currently not available in Korean hospitals. Even in the diagnosis of MP infection, both serologic and molecular test have limitation: inability to differentiate current illness from carriage or asymptomatic infection. Combining these 2 diagnostic methods and excluding infection caused by other respiratory pathogens allow a more reliable diagnosis. This effort is even more demanding in recent years to keep children from unnecessary exposure to secondary antibiotics. Although several observational studies have reported that tetracycline and fluoroquinolone, which are considered in the treatment of refractory MP pneumonia, have efficacy of shortening the duration of fever and respiratory symptoms, those findings need to be proven by well-designed prospective studies. The use of tetracycline and fluoroquinolone in children is generally tolerable, as supported by many observational data. However, since concerns about side effects still remain, careful consideration about benefits and risks is needed to decide their use.

Fluoroquinolone and no risk of Achilles-tendinopathy in childhood pneumonia under eight years of age-a nationwide retrospective cohort

Background

The emergence of macrolide-resistant Mycoplasma pneumoniae pneumonia (MRMP) has made its treatment challenging. A few guidelines have recommended fluoroquinolones (FQs) as second-line drugs of choice for treating MRMP in children under the age of eight, but concerns about potential adverse events (i.e., Achilles tendinopathy; AT) have been raised. The aim of this study was to investigate the relationship between the use of FQs and the risk of AT in pneumonia in children under eight years of age.

Methods

Children hospitalized with pneumonia (total of 2,213,807 episodes) from 2002 to 2017 were enrolled utilizing the Korean National Health Insurance Sharing Service (NHISS) database. The independent risk of FQs for AT was analyzed by a generalized estimating equation with adjustment for age, sex, and underlying diseases.

Results

Among 2,213,807 episodes of pneumonia hospitalization, children in a total of 6,229 episodes (0.28%) were treated with FQs (levofloxacin 40.9%, ciprofloxacin 36.1%, moxifloxacin 11.6%, and others 11.4%). The FQ-exposure group showed a 0.19% (12/6,229) incidence of AT within 30 days after the first administration of FQ. The use of FQs increased the risk of AT (OR 3.00; 95% CI: 1.71–5.29), but became null after adjusting for age, sex, and underlying diseases (aOR 0.85; 95% CI: 0.48–1.51). All AT related to the use of FQs occurred after the use of ciprofloxacin or levofloxacin, and not in children under eight years of age.

Conclusions

AT was a rare adverse event of FQ use for childhood pneumonia, particularly under eight years of age. Clinicians could consider using FQs as a second-line option in the treatment of childhood pneumonia when there are no alternative therapeutic options.

Comparison of different detection methods for Mycoplasma pneumoniae infection in children with community-acquired pneumonia

BACKGROUND

Due to the lack of a sensitive, specific and rapid detection method, aetiological diagnosis of pneumonia caused by Mycoplasma pneumoniae (M. pneumoniae, MP) is a constantly challenging issue. This retrospective study aimed to compare the diagnostic methods for Mycoplasma pneumoniae in children and evaluate their values.

METHODS

From November 2018 to June 2019, 830 children with community-acquired pneumonia were selected from the Department of Respiratory Medicine, Shanghai Children's Medical Center. On the first day of hospitalization, sputum, throat swab and venous blood samples were collected to analyse MP-IgM (particle agglutination, PA), MP-IgM (immune colloidal gold technique, GICT), MP-DNA, MP-RNA (simultaneous amplification and testing, SAT) and MP-DNA (real-time polymerase chain reaction, RT-PCR).

RESULTS

Among these 830 children, RT-PCR showed that the positive rate was 36.6% (304/830), in which the positive rate of macrolide resistance (A2063G mutation) accounted for 86.2% of cases (262/304). Using RT-PCR as the standard, MP-RNA (SAT) had the highest specificity (97.5%), and MP-IgM (PA) had the highest sensitivity (74.0%) and Youden index (53.7%). If MP-RNA (SAT) was combined with MP-IgM (PA), its Kappa value (0.602), sensitivity (84.2%), specificity (78.7%) and Youden index (62.9%) were higher than those of single M. pneumoniae detection.

CONCLUSIONS

Our research indicated that a combination of MP-RNA (SAT) plus MP-IgM (PA) might lead to reliable results as an early diagnostic method for children with clinical manifestations of Mycoplasma pneumoniae pneumonia.

Quantitative proteomics analysis of Mycoplasma pneumoniae identifies potential macrolide resistance determinants

Mycoplasma pneumoniae is one of the leading causes of community-acquired pneumonia in children and adolescents. Because of the wide application of macrolides in clinical treatment, macrolide-resistant M. pneumoniae strains have become increasingly common worldwide. However, the molecular mechanisms underlying drug resistance in M. pneumoniae are poorly understood. In the present work, we analyzed the whole proteomes of macrolide-sensitive and macrolide-resistant strains of M. pneumoniae using a tandem mass tag-labeling quantitative proteomic technique, Data are available via ProteomeXchange with identifier PXD022220. In total, 165 differentially expressed proteins were identified, of which 80 were upregulated and 85 were downregulated in the drug-resistant strain compared with the sensitive strain. Functional analysis revealed that these proteins were predominantly involved in protein and peptide biosynthesis processes, the ribosome, and transmembrane transporter activity, which implicates them in the mechanism(s) of resistance of M. pneumoniae to macrolides. Our results provide new insights into drug resistance in M. pneumoniae and identify potential targets for further studies on resistance mechanisms in this bacterium.

Mycoplasma pneumoniae: a pathogen with unsolved therapeutic problems

INTRODUCTION

Despite the amount of new information, the most effective approach for the diagnosis and treatment of Mycoplasma pneumoniae infections is not established. In this narrative review the pharmacological options for macrolide-resistant (ML) M. pneumoniae infections in children are discussed.

AREAS COVERED

Despite significant improvement in the diagnosis and in the definition of diseases potentially associated with this pathogen, not all the problems related to M. pneumoniae infection are solved. True epidemiology of M. pneumoniae diseases and the real role of this pathogen in extra-respiratory manifestations is still unestablished. This reflects on therapy. It is not known whether antibiotics are really needed in all the cases, independently of severity and localization. The choice of antibiotic therapy is debated as it is not known whether ML resistance has clinical relevance. Moreover, not precisely defined is the clinical importance of corticosteroids for improvement of severe cases, including those associated with ML-resistant strains.

EXPERT OPINION

Improvement in M. pneumoniae identification is mandatory to reduce antibiotics overuse , especially in the presence of ML-resistant strains. Priority for future studies includes the evaluation of the true benefit of therapeutic approaches including corticosteroids in patients with severe CAP and in those with extra-respiratory M. pneumoniae diseases.

How does one choose the appropriate pharmacotherapy for children with lower respiratory tract infections?

INTRODUCTION

The definition of acute lower respiratory tract infection (LRTI) includes any infection involving the respiratory tract below the level of the larynx. In children, the most common acute LRTIs, and those with the greatest clinical relevance, are community-acquired pneumonia (CAP), bronchiolitis, bronchitis and tuberculosis (TB). The clinical relevance of LRTIs implies that they must be addressed with the most effective therapy. Antibiotics and antivirals play an essential role in this regard.

AREAS COVERED

In this paper, the most recent advances in the drug treatment of LRTIs in children are discussed.

EXPERT OPINION

Although LRTIs are extremely common and one of the most important causes of hospitalization and death in children, anti-infective therapy for these diseases remains unsatisfactory. For CAP and BR, the most important problem is the overuse and misuse of antibiotics; for BCL, the lack of drugs with demonstrated efficacy, safety and tolerability; for TB, the poor knowledge on the true efficacy and safety of the new drugs specifically planned to overcome the problem of MDR M. tuberculosis strains. There is still a long way to go for the therapy of pediatric LRTIs to be considered satisfactory.

Immunochromatography for the diagnosis of Mycoplasma pneumoniae infection: A systematic review and meta-analysis

The aim of this study was to evaluate the diagnostic performance of immunochromatographic tests (ICTs) for the detection of Mycoplasma pneumoniae. Medline/Pubmed, Embase, the Cochrane Library, and ISI Web of Science were searched through June 12, 2019 for relevant studies that used ICTs for the detection of M. pneumoniae infection with polymerase chain reaction (PCR) or microbial culturing as reference standards. Pooled diagnostic accuracy with 95% confidence interval (CI) was calculated using a bivariate random effects model. We also constructed summary receiver operating characteristic curves and calculated the area under the curve (AUC). Statistical heterogeneity was evaluated by χ² test or Cochrane’s Q test. Thirteen studies including 2,235 samples were included in the meta-analysis. The pooled sensitivity and specificity for diagnosing M. pneumoniae infection were 0.70 (95% CI: 0.59–0.79) and 0.92 (95% CI: 0.87–0.95), respectively. The positive likelihood ratio (LR) was 8.94 (95% CI: 4.90–14.80), negative LR 0.33 (95% CI: 0.22–0.46), diagnostic odds ratio 29.20 (95% CI: 10.70–64.20), and AUC 0.904. In subgroup analysis, ICTs demonstrated similar pooled sensitivities and specificities in populations of children only and mixed populations (children + adults). Specimens obtained from oropharyngeal swabs exhibited a higher sensitivity and specificity than those of nasopharyngeal swab. Moreover, pooled estimates of sensitivity and accuracy for studies using PCR as a reference standard were higher than those using culture. The pooled sensitivity and specificity of Ribotest Mycoplasma^®, the commercial kit most commonly used in the included studies, were 0.66 and 0.89, respectively. Overall, ICT is a rapid user-friendly method for diagnosing M. pneumoniae infection with moderate sensitivity, high specificity, and high accuracy. This suggests that ICT may be useful in the diagnostic workup of M. pneumoniae infection; however, additional studies are needed for evaluating the potential impact of ICT in clinical practice.

Ameliorative effect of Albizia chinensis synthesized ZnO-NPs on Mycoplasma pneumoniae infected pneumonia mice model

BACKGROUND

Mycoplasma pneumoniae (MP) is a common cause of community-acquired pneumonia (CAP) among the children and adults that results upper and lower respiratory tract infections.

OBJECTIVE

This study was aimed to inspect the ameliorative action of A. chinensis synthesized ZnONPs against M. pneumoniae infected pneumonia mice model.

MATERIALS AND METHODS

ZnO NPs was synthesized from Albizia chinensis bark extract and characterized by UV-Vis spectroscopy, Fourier Transform Infrared (FTIR), Transmission Electron Microscopy (TEM), energy dispersive X-ray (EDX) and atomic force microscope (AFM) analyses. The antibacterial effectual of synthesized ZnONPs were examined against clinical pathogens. The pneumonia was induced to BALB/c mice via injecting the M. pneumoniae and treated with synthesized ZnONPs, followed by the total protein content, total cell counts and inflammatory mediators level was assessed in the BALF of experimental animals. The Histopathological investigation was done in the lung tissues of test animals.

RESULTS

The outcomes of this work revealed that the formulated ZnONPs was quasi-spherical, radial and cylindrical; the size was identified as 116.5 ± 27.45 nm in diameter. The in vitro antimicrobial potential of formulated ZnO-NPs displayed noticeable inhibitory capacity against the tested fungal and bacterial strains. The administration of synthesized ZnO-NPs in MP infected mice model has significantly reduced the levels of total protein, inflammatory cells, inflammatory cytokines such as IL-1, IL-6, IL-8, tumour necrosis factor-alpha (TNF-a) and transforming growth factor (TGF). Besides, the histopathological examination of MP infected mice lung tissue showed the cellular arrangements were effectively retained after administration of synthesized ZnO-NPs.

CONCLUSION

In conclusion, synthesized ZnO-NPs alleviate pneumonia progression via reducing the level of inflammatory cytokines and inflammatory cells in MP infected mice model.

A Peculiar Case of Pneumonia due to Mycoplasma pneumoniae in a Child with Cystic Fibrosis and Sensibilization to Aspergillus fumigatus

Aspergillus fumigatus plays a major role in pulmonary exacerbations in patients with cystic fibrosis. The most common A. fumigatus diseases are those based on immune-mediated response to A. fumigatus antigens; including allergic bronchopulmonary aspergillosis (ABPA). In this condition; the presence of A. fumigatus in the lower respiratory tract triggers an IgE-mediated hypersensitivity response that causes airway inflammation; bronchospasms; and bronchiectasis. This case report describes a ten-year-old male patient suffering from cystic fibrosis (CF) in whom the diagnosis of ABPA occurred in association with pneumonia due to Mycoplasma pneumoniae more than two weeks after hospitalization. This case is a good example of how difficult the identification of ABPA in CF patients can be and highlights that ABPA can occur in association with co-infections due to other pathogens. In order to avoid the risk of a late ABPA diagnosis, it is imperative that the diagnostic criteria guidelines are reviewed and standardized.

Efficacy of glucocorticoids for the treatment of macrolide refractory mycoplasma pneumonia in children: meta-analysis of randomized controlled trials

Background

Mycoplasma pneumoniae is one of the most common pathogens causing community acquired pneumonia in children. Although the rate of macrolide-refractory Mycoplasma pneumoniae (MRMP) has increased, systemic glucocorticoids as a treatment option has not been validated yet. The purpose of this study was to assess the efficacy of glucocorticoids add-on in the treatment of MRMP in children through systematic review and meta-analysis.

Methods

Data sources

A systematic literature search was conducted using ten electronic bibliographic databases including English, Korean, Chinese and Japanese languages, up to March 8, 2018.

Study selection

The study was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist and selected randomized control trials which compared the efficacy of glucocorticoids add-on to macrolide in the treatment of MRMP in children.

Data extraction

Two independent reviewers extracted: primary outcomes as hospital days, fever duration, and change in C-reactive protein (CRP) and main analysis was performed through meta-analysis with random effects model.

Results

Twenty-four unique randomized controlled trials met the inclusion criteria. The mean length of hospital stay in glucocorticoids treatment group was significantly shorter than that in conventional macrolide-treatment group (Weighted mean difference (WMD) = − 4.03 days). The mean length of fever duration was significantly shorter in the glucocorticoid treatment group in comparison with the conventional treatment group (WMD = -3.32 days). Level of CRP after treatment was significantly lower in the glucocorticoid treatment group than that in the conventional treatment group (WMD = -16.03). Sensitivity analysis and subgroup analysis showed no significant improvement in heterogeneity. As limitations of the study, most of the studies included were from a single country and we were unable to control for heterogeneity across interventions, lack of standardized measures, and different time points of assessments across studies.

Conclusions

Glucocorticoid add-on treatment for MRMP can significantly shorten the duration of fever and hospital stay and decrease the level of CRP. These results should be confirmed by adequately powered studies in the future.

Development of loop-mediated isothermal amplification coupled with nanoparticle-based lateral flow biosensor assay for Mycoplasma pneumoniae detection

Mycoplasma pneumoniae (MP) is one of the most common pathogens causing respiratory tract infection, especially for community-acquired pneumonia (CAP) in school-age children. There was considerable amount of studies on loop-mediated isothermal amplification (LAMP) assay for MP detection. However, the result interpretation of these developed LAMP assays was sophisticated and subjective. Therefore, we developed and evaluated a LAMP coupled with nanoparticle-based lateral flow biosensor (LFB) assay (LAMP-LFB) for simple, reliable, and objective identification of MP (MP-LAMP-LFB). Six primers specific to P1 gene of MP were designed, and the preferred temperature for this assay was confirmed to be 65 °C. The amplification products could be visually interpreted by LFB within 2 min. The MP-LAMP-LFB assay specifically identified DNA templates of MP, and no cross-reactivity with other pathogens was obtained. The limit of the detection for this assay was 600 fg of DNA templates in pure cultures, which was in complete accordance with colorimetric indicator detection and agarose gel electrophoresis analysis. This assay was applied to 209 oropharyngeal swab specimens collected from children with acute respiratory tract infection for clinical evaluation, and compared to real-time PCR detection. Using the LAMP-LFB and real-time PCR assay, the positive rates of MP were 47.8% and 31.6%, respectively. Results suggested that the LAMP-LFB assay displayed high sensitivity compared to real-time PCR method. In summary, LAMP-LFB assay established here was a simple, objective, and sensitive assay for MP detection, which can be widely applied in clinical settings, especially in rural areas.

Outbreak of macrolide-resistant mycoplasma pneumoniae in a primary school in Beijing, China in 2018

Background

On 7th June, 2018, a primary school in Beijing, China notified Shunyi CDC of an outbreak of acute respiratory disease characterized by fever and cough among students and resulting in nine hospitalization cases during the preceding 2 weeks. We started an investigation to identify the etiologic agent, find additional cases, develop and implement control measures.

Methods

We defined probable cases as students, teachers and other staffs in the school developed fever (T ≥ 37.5 °C) with cough or sore throat; or a diagnosis of pneumonia during May 1–June 31, 2018. Confirmed cases were probable cases with Mycoplasma pneumoniae detected in oropharyngeal (OP) swabs by quantitative real-time polymerase chain reaction (qPCR). We searched case by reviewing school absenteeism records and interviewing students, teachers and staff in this school. Oropharyngeal swabs were collected from symptomatic students. Two qPCR) assay, a duplex qPCR assay, and sequencing were performed to determine the pathogen, genotype and macrolide resistance at the gene level, respectively.

Results

From May 1st to June 31st, 2018, we identified 55 cases (36 probable and 19 confirmed), of whom 25 (45%) were hospitalized for complications. All cases were students, none of the teachers and other staffs in the school were with similar symptoms. The attack rate (AR) was 3.9% (55/1398) for all students. The cases were mainly male (58%), with an age range of 7–8 years (median: 7 years). 72% (18/25) of inpatients had radiograph findings consistent with pneumonia, and some cases were hospitalized for up to 4 weeks. Pathogen detection results indicated that Mycoplasma pneumonia (M. pneumoniae) P1 type 1 was the causative agent in this outbreak, and the strain harbored one point mutation of A to G at position 2063.

Conclusions

The infections by macrolide-resistant M. pneumoniae are not always mild and pneumonia was common and M. pneumoniae could causes serious complications which require long-term hospitalization. In the future infectious disease prevention and control practice, M. pneumoniae should be paid more attention. It is necessary to establish and improve the pathogen and drug resistance surveillance system in order to prevent and control such mutated strains of M. pneumoniae from causing future outbreaks or epidemics in China.

Molecular and clinical characteristics of severe Mycoplasma pneumoniae pneumonia in children

OBJECTIVES

To analyze the molecular and the clinical characteristics of Mycoplasma pneumoniae (Mp) pneumonia (MPP) and to explore the related factors predicting severe MPP (SMPP).

METHODS

A total of 423 pediatric cases of MPP were retrospectively analyzed, in 2013-2017, in Beijing, China. Clinical information was collected from the medical records. Mp-positive specimens were characterized using P1 typing and multiple locus variable-number tandem repeat analysis (MLVA). The macrolide resistance-associated mutations were also detected.

RESULTS

The predominant genotype was P1-1 (88.2%) and M4-5-7-2 (87.5%), whereas percentages of type P1-2 and M3-5-6-2 increased across the 5-year period. The mutation rate of genotype M4-5-7-2 (365/370, 98.6%) was significantly higher than that of the genotype M3-5-6-2 (15/48, 32.25%; P = 0.000). Overall, 180 (42.6%) of the 423 Mp-positive patients were coinfected with other pathogens. Respiratory syncytial virus coinfection (24/180, 13.3%) was more common in cases typed M3-5-6-2 (4/23, 17.4%) than that of M4-5-7-2 (20/155, 12.9%; P = 0.038). Pleural effusion accounted for 52.6% (169/321) of the observed complications. In the mono-infection cases, cases typed M3-5-6-2 (56%, 14/25) were significantly (P = 0.020) associated with pleural effusion compared with those typed M4-5-7-2 (32.6%, 70/215); 84% (21/25) of specimens typed M3-5-6-2 were diagnosed as SMPP, whereas 63.7% (137/215) of specimens typed M4-5-7-2 were diagnosed as SMPP (P = 0.043).

CONCLUSIONS

In our study, we proposed for the first time that the mono-infection patients with Mp typed M3-5-6-2 appear to have a higher risk for progressing to SMPP. MLVA typing can provide hints on the clinical characteristics of Mpp.

Multiplex Platforms for the Identification of Respiratory Pathogens: Are They Useful in Pediatric Clinical Practice?

Respiratory tract infections (RTIs) are extremely common especially in the first year of life. Knowledge of the etiology of a RTI is essential to facilitate the appropriate management and the implementation of the most effective control measures. This perspective explains why laboratory methods that can identify pathogens in respiratory secretions have been developed over the course of many years. High-complexity multiplex panel assays that can simultaneously detect up to 20 viruses and up to four bacteria within a few hours have been marketed. However, are these platforms actually useful in pediatric clinical practice? In this manuscript, we showed that these platforms appear to be particularly important for epidemiological studies and clinical research. On the contrary, their routine use in pediatric clinical practice remains debatable. They can be used only in the hospital as they require specific equipment and laboratory technicians with considerable knowledge, training, and experience. Moreover, despite more sensitive and specific than other tests routinely used for respiratory pathogen identification, they do not offer significantly advantage for detection of the true etiology of a respiratory disease. Furthermore, knowledge of which virus is the cause of a respiratory disease is not useful from a therapeutic point of view unless influenza virus or respiratory syncytial virus are the infecting agents as effective drugs are available only for these pathogens. On the other hand, multiplex platforms can be justified in the presence of severe clinical manifestations, and in immunocompromised patients for whom specific treatment option can be available, particularly when they can be used simultaneously with platforms that allow identification of antimicrobial resistance to commonly used drugs. It is highly likely that these platforms, particularly those with high sensitivity and specificity and with low turnaround time, will become essential when new drugs effective and safe against most of the respiratory viruses will be available. Further studies on how to differentiate carriers from patients with true disease, as well as studies on the implications of coinfections and identification of antimicrobial resistance, are warranted.

Atypical and Typical Bacteria in Children with Community Acquired Pneumonia

This study seeks to determine the pathogens in respiratory specimens and blood serum obtained from children who present with community acquired pneumonia (CAP) diagnosed on the basis of clinical and radiological evidence. The study group consisted of 46 hospitalized children aged 1-11 years. The material for research consisted of pharyngeal swabs and samples of blood serum. One hundred and thirty eight pharyngeal swabs were examined for the presence of C. pneumoniae antigen, C. pneumoniae DNA, and for typical pathogens. C. pneumoniae DNA was detected in pharyngeal swabs with nested PCR. Classical microbiological culture was used for detection of typical bacteria. ELISA test were used for detection anti-C. pneumoniae and anti-M. pneumoniae antibodies in the serum. C. pneumoniae DNA was identified in 10.9% of children. Positive culture for typical pathogens was observed in 8.7% of children. Specific anti-C. pneumoniae IgM antibodies were found in 8.7% of children, and IgG and IgA antibodies in 1 child each. Specific anti-M. pneumoniae IgG antibodies were found in 13.1% of children and IgM antibodies in 1 child. We conclude that the underlying bacterial etiology of CAP is rather rarely conclusively confirmed in children. Nonetheless, determining the etiology of CAP is essential for the choice of treatment to optimize the use and effectiveness of antimicrobials and to avoid adverse effect. Due to considerable variations in the power of detection of the type of atypical bacteria causing CAP, the search for the optimum diagnostic methods continues.

An adult case of severe life-threatening Mycoplasma pneumoniae pneumonia due to a macrolide-resistant strain, Japan: a case report

Background

Until now, the prevalence of macrolide-resistant Mycoplasma pneumoniae (MP) infection among adult patients has been low, and severe MP pneumonia due to a macrolide-resistant strain has seldom been reported. Here, we describe a rare case of severe life-threatening MP pneumonia due to a macrolide-resistant strain in an adult, which was finally treated with fluoroquinolone and tetracycline after failed treatment with macrolide and corticosteroid.

Case presentation

A 39-year-old apparently healthy woman complained of fever and productive cough. Three days after onset, she was admitted to a local general hospital. On admission, her vital signs were stable except for high-grade fever. The patient’s chest X-ray and chest computed tomography images revealed subsegmental consolidation in her right lower lobe. Treatment with ampicillin/sulbactam, and azithromycin were initiated under a clinical diagnosis of community-acquired pneumonia. After treatment initiation, her fever had not subsided, and the pulmonary lesion had extended to the entire lower lobe. Thus, treatment with prednisolone as steroid pulse therapy was initiated from clinical day 7. However, neither her symptoms nor her pulmonary lesion improved; therefore, she was transferred to our hospital for further examination and treatment. On admission (clinical day 14), her indirect hemagglutination titer for MP was elevated at 1:2560, and bronchoalveolar fluid examination yielded positive results for the mycoplasma antigen. Based on these clinical findings, we confirmed a case of severe life-threatening MP pneumonia. Since her respiratory condition was extremely severe, we initiated levofloxacin and tetracycline. Two days later (clinical day 16), her fever, malaise, and hypoxia resolved, and her pulmonary lesions had significantly improved.

Further molecular identification yielded the DNA of MP from her bronchoalveolar fluid, and mutation of A2063G in the 23S rRNA gene was revealed. Based on these results and the clinical course, we confirmed our case as severe MP pneumonia due to a macrolide-resistant strain.

Conclusion

More awareness is needed on the emergence of macrolide-resistant MP infection in adults, because severe infection could develop despite initial treatment with macrolide and steroid therapy, which are generally considered as standard therapy for MP.

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.

The burden of community-acquired bacterial pneumonia in the era of antibiotic resistance

INTRODUCTION

Community-acquired pneumonia (CAP) is a significant global health problem and leading cause of death and hospitalization in both the US and abroad. Increasing macrolide resistance among Streptococcus pneumoniae and other pathogens results in a greater disease burden, along with changing demographics and a higher preponderance of comorbid conditions. Areas covered: This review summarizes current data on the clinical and economic burden of CAP, with particular focus on community-acquired bacterial pneumonia (CABP). Incidence, morbidity and mortality, and healthcare costs for the US and other regions of the world are among the topics covered. Major factors that are believed to be contributing to the increased impact of CABP, including antimicrobial resistance, the aging population, and the incidence of comorbidities are discussed, as well as unmet needs in current CABP management. Expert commentary: The clinical and economic burden of CABP is staggering, far-reaching, and expected to increase in the future as new antibiotic resistance mechanisms emerge and the world's population ages. Important measures must be initiated to stabilize and potentially decrease this burden. Urgent needs in CABP management include the development of new antimicrobials, adjuvant therapies, and rapid diagnostics.

Pathogenesis and Treatment of Neurologic Diseases Associated With Mycoplasma pneumoniae Infection

Mycoplasma pneumoniae is mainly recognized as a respiratory pathogen, although it is associated with the development of several extra-respiratory conditions in up to 25% of the cases. Diseases affecting the nervous system, both the peripheral (PNS) and the central nervous system (CNS), are the most severe. In some cases, particularly those that involve the CNS, M. pneumoniae-related neuropathies can lead to death or to persistent neurologic problems with a significant impact on health and a non-marginal reduction in the quality of life of the patients. However, the pathogenesis of most of the M. pneumoniae-related neuropathies remains undefined. The main aim of this paper is to discuss what is presently known regarding the pathogenesis and treatment of the most common neurologic disorders associated with M. pneumoniae infection. Unfortunately, the lack of knowledge of the true pathogenesis of most of the cases of M. pneumoniae-mediated neurological diseases explains why treatment is not precisely defined. However, antibiotic treatment with drugs that are active against M. pneumoniae and able to pass the blood-brain barrier is recommended, even though the best drug, dosage, and duration of therapy have not been established. Sporadic clinical reports seem to indicate that because immunity plays a relevant role in the severity of the condition and outcome, attempts to reduce the immune response can be useful. However, further studies are needed before the problem of the best therapy for M. pneumoniae-mediated neurological diseases can be efficiently solved.

Effects of Macrolide Treatment during the Hospitalization of Children with Childhood Wheezing Disease: A Systematic Review and Meta-Analysis

Children are susceptible to a variety of respiratory infections. Wheezing is a common sign presented by children with respiratory infections. Asthma, bronchiolitis, and bronchitis are common causes of childhood wheezing disease (CWD) and are regarded as overlapping disease spectra. Macrolides are common antimicrobial agents with anti-inflammatory effects. We conducted a comprehensive literature search and a systematic review of studies that investigated the influences of macrolide treatment on CWD. The primary outcomes were the impact of macrolides on hospitalization courses of patients with CWD. Data pertaining to the study population, macrolide treatment, hospital courses, and recurrences were analyzed. Twenty-three studies with a combined study population of 2210 patients were included in the systematic review. Any kind of benefit from macrolide treatment was observed in approximately two-thirds of the studies (15/23). Eight studies were included in the meta-analysis to investigate the influence of macrolides on the length of stay (LOS), duration of oxygen demand (DOD), symptoms and signs of respiratory distress, and re-admission rates. Although the benefits of macrolide treatment were reported in several of the studies, no significant differences in LOS, DOD, symptoms and signs of respiratory distress, or re-admission rates were observed in patients undergoing macrolide treatment. In conclusion, any kind of benefit of macrolide treatment was observed in approximately two-thirds of the studies; however, no obvious benefits of macrolide treatment were observed in the hospitalization courses of children with CWD. The routine use of macrolides to improve the hospitalization course of children with CWD is not suggested.

Ameliorative Effects of Infantile Feire Kechuan Oral Solution on Mycoplasma Pneumoniae Pneumonia in Infant Mouse and Rat Models

Mycoplasma pneumoniae (MP) infection is a major pathogen of community-acquired pneumonia (CAP) in children worldwide. Infantile Feire Kechuan Oral Solution (IFKOS) has been used for the treatment of MP pneumonia clinically in China for many years. The present study was designed to investigate the therapeutic effect of IFKOS on MP pneumonia and explore the potential mechanism of the actions. The infant BALB/c mouse and Wistar rat models of MP infection were successfully established to confirm the therapeutic effects of IFKOS, followed by assays for related cytokines and investigations of the IgM response involved. The results showed that IFKOS exhibited an inhibitory effect on pulmonary index (PI) and effectively reduced the degree of lesions in the lungs. The lethal rate of mice was significantly decreased while survival time of mice was dramatically increased by IFKOS treatment in comparison to infection control, respectively. IFKOS treatment (40, 20, and 10ml/kg) significantly decreased the level of MP-IgM in a dose-dependent manner, whereas IFKOS showed no obvious inhibitory effect on the increase of relative expression of MP-DNA. In addition, the elevated IL-2 and TNF-α levels were significantly reduced and the decreased IL-6 level was significantly enhanced by IFKOS treatment. Our study demonstrates that IFKOS has inhibitory effect on MP infection in infant mouse and rat models of MP pneumonia and protective effect from lethal MP challenge in infant murine model. These anti-MP effects might be related to suppression of the IgM response and a reversal the imbalance of Th1/Th2 cytokines induced by MP infection.

Facilitators of interdepartmental quality improvement: a mixed-methods analysis of a collaborative to improve pediatric community-acquired pneumonia management

BACKGROUND

Emergency medicine and paediatric hospital medicine physicians each provide a portion of the initial clinical care for the majority of hospitalised children in the USA. While these disciplines share goals to increase quality of care, there are scant data describing their collaboration. Our national, multihospital learning collaborative, which aimed to increase narrow-spectrum antibiotic prescribing for paediatric community-acquired pneumonia, provided an opportunity to examine factors influencing the success of quality improvement efforts across these two clinical departments.

OBJECTIVE

To identify barriers to and facilitators of interdepartmental quality improvement implementation, with a particular focus on increasing narrow-spectrum antibiotic use in the emergency department and inpatient settings for children hospitalised with pneumonia.

METHODS

We used a mixed-methods design, analysing interviews, written reports and quality measures. To describe hospital characteristics and quality measures, we calculated medians/IQRs for continuous variables, frequencies for categorical variables and Pearson correlation coefficients. We conducted in-depth, semistructured interviews by phone with collaborative site leaders; interviews were transcribed verbatim and, with progress reports, analysed using a general inductive approach.

RESULTS

47 US-based hospitals were included in this analysis. Qualitative analysis of 35 interview transcripts and 142 written reports yielded eight inter-related domains that facilitated successful interdepartmental quality improvement: (1) hospital leadership and support, (2) quality improvement champions, (3) evidence supporting the intervention, (4) national health system influences, (5) collaborative culture, (6) departments' structure and resources, (7) quality improvement implementation strategies and (8) interdepartmental relationships.

CONCLUSIONS

The conceptual framework presented here may be used to identify hospitals' strengths and potential barriers to successful implementation of quality improvement efforts across clinical departments.

A study of community-acquired Mycoplasma pneumoniae in Yantai, China

Introduction:

Community-acquired pneumonia (CAP) is a global disease responsible for a large number of deaths, with significant economic impact. As diagnostic tools have increased in sensitivity, understanding of the etiology of CAP has begun to change. Mycoplasma pneumoniae is one of the major pathogens causing CAP. Macrolides and related antibiotics are first-line treatments for M. pneumoniae. Macrolide resistance has been spreading for 15 years and now occurs in worldwide. We undertook the first study on macrolide resistance of M. pneumoniae in Yantai. This may be helpful to determine the appropriate therapy for CAP in this population.

Objective:

To investigate the rate and mechanism of macrolide resistance in Yantai.

Methods:

Pharyngeal swab samples were collected from adult CAP patients. Samples were assayed by polymerase chain reaction (PCR) and cultivated to test for M. pneumoniae. Nested PCR was used to specifically amplify M. pneumoniae 23S rRNA gene fragments containing mutations, and amplicons were analyzed by CE-SSCP for macrolide resistance mutations. Results were confirmed by sequencing. Twenty-seven strains of M. pneumoniae were isolated and the activities of nine antibiotics against M. pneumoniae were tested in vitro.

Results:

Out of 128 samples tested, 27 were positive for M. pneumoniae. Mycoplasma 100% macrolides resistance to Mycoplasma pneumoniae. The mechanism of macrolides resistance was A2063G point mutation in the sequence directly binding to macrolides in the 23S rRNA V domain in vitro. The mean pyretolytic time for the fluoroquinolone group was 4.7 ±2.9 d, which was significantly shorter than 8.2 ±4.1 d for the azithromycin group.

Conclusions:

Macrolides are not the first-line treatment for M. pneumoniae respiratory tract infections in Yantai.

Macrolides in Children With Community-Acquired Pneumonia: Panacea or Placebo?

Pneumonia, most often caused by a respiratory virus, is common in childhood. Mycoplasma pneumoniae also is detected frequently, particularly in older children in the era of pneumococcal conjugate vaccination. Despite recommendations for β-lactam antibiotics, macrolide antibiotics, including erythromycin, clarithromycin, and azithromycin, are prescribed frequently to children with acute lower respiratory infection. However, the significance of detecting "atypical" pathogens, including M pneumoniae, in children remains contentious. Considering the potential for antibacterial and anti-inflammatory activities of macrolides, our understanding of the role of these drugs in acute and chronic infections and in inflammatory conditions is changing. Some observational data have revealed improved outcomes in adults and children with pneumonia who are prescribed macrolides, although its widespread use has led to increases in macrolide resistance in Streptococcus pneumoniae and M pneumoniae. Clinical trials to define the role of macrolides in pediatric acute respiratory infection must be prioritized.

Development of Mycoplasma pneumoniae biofilms in vitro and the limited role of motility

Mycoplasma pneumoniae is a bacterial pathogen of humans that is a major causative agent of chronic respiratory disease. M. pneumoniae infections often recur even after successful treatment of symptoms with antibiotics, and resistance to antibiotics is increasing worldwide, with nearly complete resistance in some places. Although biofilms often contribute to chronicity and resistance, M. pneumoniae biofilms remain poorly characterized. Scanning electron microscopy revealed that cells of wild-type (WT) M. pneumoniae strain M129 biofilms, as well as mutants II-3 and II-3R, in vitro became increasingly rounded as the biofilm towers matured over 5 days. The role of gliding motility in biofilm formation was addressed by analyzing differences in biofilm architecture in non-motile mutant II-3R and hypermotile mutant prpC-and by using time-lapse microcinematography to measure flux of cells around biofilm towers. There were no major differences in biofilm architecture between WT and motility mutants, with perhaps a slight tendency for the prpC- cells to spread outside towers during early stages of biofilm formation. Consistent with an insignificant role of motility in biofilm development, flux of cells near towers, which was low, was dominated by exit of cells. Immunofluorescence microscopy revealed that motility-associated attachment organelle (AO) proteins exhibited no discernable changes in localization to foci over time, but immunoblotting identified a decrease in steady-state levels of protein P200, which is required for normal gliding speed, as the WT culture aged. Non-adherent strain II-3 and non-motile strain II-3R also exhibited a steady decrease in P200 steady-state levels, suggesting that the decrease in P200 levels was not a response to changes in gliding behavior during maturation. We conclude that M. pneumoniae cells undergo morphological changes as biofilms mature, motility plays no major role in biofilm development, and P200 loss might be related to maturation of cells. This study helps to characterize potential therapeutic targets for M. pneumoniae infections.

A sensitive and rapid immunoassay for Mycoplasma pneumoniae in children with pneumonia based on single-walled carbon nanotubes

Mycoplasma pneumoniae(MP) is a leading pathogen of respiratory infection, especially community-acquired pneumonia (CAP), in children worldwide. However, its diagnosis is frequently ineffective because bacterial culture and serology test are usually positive 1–2 weeks or more after the disease onset. To achieve a better detection efficiency, the single-walled carbon nanotubes(SWCNT) were coupled with the colloidal gold-monoclonal antibody immunochromatographic strips(CGIC). Interestingly, the SWCNT/CGIC assay allowed MP identification, with a detection limit of 1 × 10² copies/ml. Using referenced throat swabs of 97 MP and 40 non-MP cases, the assay yielded 72.2% sensitivity, 100.0% specificity, 100.0% positive predictive value (PPV), 59.7% negative predictive value (NPV). In summary, our assay was far more effective than any conventional methods for the diagnosis of acute MP. The ease of use, rapid and stability further enhance its feasibility for clinical use on-site.

Mycoplasma pneumoniae from the Respiratory Tract and Beyond

Mycoplasma pneumoniae is an important cause of respiratory tract infections in children as well as adults that can range in severity from mild to life-threatening. Over the past several years there has been much new information published concerning infections caused by this organism. New molecular-based tests for M. pneumoniae detection are now commercially available in the United States, and advances in molecular typing systems have enhanced understanding of the epidemiology of infections. More strains have had their entire genome sequences published, providing additional insights into pathogenic mechanisms. Clinically significant acquired macrolide resistance has emerged worldwide and is now complicating treatment. In vitro susceptibility testing methods have been standardized, and several new drugs that may be effective against this organism are undergoing development. This review focuses on the many new developments that have occurred over the past several years that enhance our understanding of this microbe, which is among the smallest bacterial pathogens but one of great clinical importance.

Mechanism of resistance acquisition and treatment of macrolide-resistant Mycoplasma pneumoniae pneumonia in children

Mycoplasma pneumoniae pneumonia (MPP) is one of the most common forms of community-acquired pneumonia in children and adolescents. Outbreaks of MPP occur in 3- to 7-year cycles worldwide; recent epidemics in Korea occurred in 2006–2007, 2011, and 2015–2016. Although MPP is known to be a mild, self-limiting disease with a good response to macrolides, it can also progress into a severe and fulminant disease. Notably, since 2000, the prevalence of macrolide-resistant MPP has rapidly increased, especially in Asian countries, recently reaching up to 80%–90%. Macrolide-resistant Mycoplasma pneumoniae (MRMP) harbors a point mutation in domain V of 23S rRNA with substitutions mainly detected at positions 2063 and 2064 of the sequence. The excessive use of macrolides may contribute to these mutations. MRMP can lead to clinically refractory pneumonia, showing no clinical or radiological response to macrolides, and can progress to severe and complicated pneumonia. Refractory MPP is characterized by an excessive immune response against the pathogen as well as direct injury caused by an increasing bacterial load. A change of antibiotics is recommended to reduce the bacterial load. Tetracyclines or quinolones can be alternatives for treating MRMP. Otherwise, corticosteroid or intravenous immunoglobulin can be added to the treatment regimen as immunomodulators to down-regulate an excessive host immune reaction and alleviate immune-mediated pulmonary injury. However, the exact starting time point, dose, or duration of immunomodulators has not been established. This review focuses on the mechanism of resistance acquisition and treatment options for MRMP pneumonia.

Pediatric Mycoplasma pneumoniae Infection Presenting with Acute Cholestatic Hepatitis and Other Extrapulmonary Manifestations in the Absence of Pneumonia

Mycoplasma pneumoniae infections mainly involve respiratory tract; however, also can manifestate other symptoms by site involved. Extrapulmonary manifestations of M. pneumoniae infection are rarely known to occur without pneumonia. Herein we report a case of a 9-year-old boy who presented with acute cholestatic hepatitis in the absence of pneumonia. Rhabdomyolysis, skin rash, and initial laboratory results suspicious of disseminated intravascular coagulopathy were also observed in this patient. M. pneumoniae infection was identified by a 4-fold increase in immunoglobulin G antibodies to M. pneumoniae between acute and convalescent sera by enzyme-linked immunosorbent assay. This is the first pediatric case in Korea of M. pneumoniae infection presenting with acute cholestatic hepatitis in the absence of pneumonia.

Prevalence and clinical manifestations of macrolide resistant Mycoplasma pneumoniae pneumonia in Korean children

Purpose

Macrolide resistance rate of Mycoplasma pneumoniae has rapidly increased in children. Studies on the clinical features between macrolide susceptible-M. pneumoniae (MSMP) and macrolide resistant-M. pneumoniae (MRMP) are lacking. The aim of this study was to identify the macrolide resistance rate of M. pneumoniae in Korean children with M. pneumoniae penupmonia in 2015 and compare manifestations between MSMP and MRMP.

Methods

Among 122 children (0–18 years old) diagnosed with M. pneumoniae pneumonia, 95 children with the results of macrolide sensitivity test were included in this study. Clinical manifestations were acquired using retrospective medical records.

Results

The macrolide resistant rate of M. pneumoniae was 87.2% (82 of 94 patients) in children with M. pneumoniae pneumonia. One patient showed a mixed type of wild type and A2063G mutation in 23S rRNA of M. pneumoniae. There were no significant differences in clinical, laboratory, and radiologic findings between the MSMP and MRMP groups at the first visit to our hospital. The time interval between initiation of macrolide and defervescence was significantly longer in the MRMP group (4.9±3.3 vs. 2.8±3.1 days, P=0.039).

Conclusion

The macrolide resistant rate of M. pneumoniae is very high in children with M. pneumoniae pneumonia in Korea. The clinical manifestations of MRMP are similar to MSMP except for the defervescence period after administration of macrolide. Continuous monitoring of the occurrence and antimicrobial susceptibility of MRMP is required to control its spread and establish strategies for treating second-line antibiotic resistant M. pneumoniae infection.

An interesting case of mycoplasma pneumonia associated multisystem involvement and diffuse alveolar hemorrhage

Severe mycoplasma pneumonia is a rare entity with only 0.5–2% of cases having a fulminant course. We present a 74-year-old woman with hypertension, diabetes mellitus and remote history of marginal zone B-cell lymphoma admitted with abdominal pain and diarrhea of 1–2 days associated with body-aches, dyspnea, dry cough and weight loss for 2–3 weeks. On physical exam, she was febrile, tachypneic, tachycardic and hypoxic on room air. Chest examination revealed diffuse crackles and end-expiratory wheezes. Laboratory tests showed anemia, acute-on-chronic kidney injury and hyaline casts and epithelial cells in the urine analysis. Chest roentgenogram and computed tomograhphy scan showed pulmonary infiltrates. Intravenous ceftriaxone and azithromycin with bronchodilators were initiated. Her clinical course was complicated by hypoxic respiratory failure, hemoptysis, and worsening of infiltrates, requiring intubation and mechanical ventilation. Bronchoscopic bronchoalveolar lavage was consistent with diffuse alveolar hemorrhage (DAH). The patient's serum was positive for IgM antibody to Mycoplasma pneumoniae [1134 U/mL] and Anti-I-specific IgM-cold-agglutining [1:40]. A diagnosis of severe mycoplasma infection with DAH was made. The patient was treated with an additional course of doxycycline, pulse dose steroids and plasmapharesis with good clinical response. Surgical lung biopsy showed focal acute lung injury. Bone marrow biopsy and fat pad biopsy were normal. She was liberated from mechanical ventilation and discharged. She returned within 24 hours of discharge with cardiac arrest and new onset right-bundle-branch-block. We hypothesize our patient had severe mycoplasma pneumonia with DAH and multisystem complications of the same including a possible venous thrombo-embolic episode leading to her demise.