Fatal outcomes in family transmission of Mycoplasma pneumoniae

Correlation of DNA load, genotyping, and clinical phenotype of Mycoplasma pneumoniae infection in children

Introduction

This study aimed to investigate the correlation between Mycoplasma pneumoniae (MP)-DNA load in the bronchoalveolar lavage fluid (BALF) of children with MP pneumonia (MPP) and its subtypes, relevant laboratory data, imaging, extrapulmonary complications in infected children, and its clinical significance in evaluating the disease.

Methods

Children hospitalized with MPP at Tianjin Children's Hospital between December 2017 and December 2020 were selected for the study, excluding those with mixed viral, bacterial, and fungal infections. Children were divided into low- and high-load groups according to the MP DNA load in BALF using real-time quantitative fluorescence polymerase chain reaction (PCR). After a successful MP culture, positive specimens were subjected to PCR-Restriction fragment length polymorphism and Multiple-locus variable number tandem repeat analysis typing. Basic data, clinical information, laboratory data, and radiological results were collected from all children included in the study.

Results

The PI-I type dominated the different load groups. Children in the low-load group had more wheezing and shortness of breath; however, children in the high-load group had a higher length of hospitalization, maximum fever temperature, higher chills/chilliness, incidence of abdominal pain, and higher C-reactive protein (CRP), procalcitonin (PCT) and aspartate aminotransferase (AST) levels. Children in the high-load group were more likely to have imaging changes such as pleural effusion, and the incidence of respiratory infections and extrapulmonary complications was higher than that of those in the low-load group. We applied Spearman's correlation analysis to clarify the relationship between MP DNA load and the clinical severity of MPP. We found that MP DNA load was positively correlated with length of hospitalization, maximum fever temperature, CRP, PCT, Interleukin-6 (IL-6), and AST levels, and negatively correlated with fever and cough durations, white blood cell count (WBC), and proportion of monocytes (MONO). The degree of correlation was as follows: length of hospitalization > IL-6 > cough duration > AST > fever duration > PCT > WBC > proportion of MONO > maximum fever temperature > CRP levels.

Conclusions

MP DNA load was not correlated with MP typing but was significantly correlated with the children's clinical phenotype. Therefore, the MP DNA load helps in the early diagnosis of infection and can better predict disease regression.

Comparison of the clinical characteristics in parents and their children in a series of family clustered Mycoplasma pneumoniae infections

BACKGROUND

Mycoplasma pneumoniae infections have increased in China recently, causing some evidence of familial clustering. The purpose of this study was to compare the clinical features of parents and children in cases of familial clustering of Mycoplasma pneumoniae infection.

METHODS

A retrospective analysis was performed on the cases of familial clustering of Mycoplasma pneumoniae infection, and the clinical characteristics of parents and children were compared.

RESULTS

We identified 63 families, of these, 57 (65.5%) adults and 65 (94.2%) children required hospitalization. Fifty-seven adults (mean age 35.1 ± 4.6 years, 80.7% female) and 55 children (mean age 6.3 ± 3.9 years, 54.5% female) were included in the analysis. The incidence of mycoplasma infection in adults had increased gradually over the past year, while the rate in children had spiked sharply since June 2023. The clinical symptoms were similar in the two groups, mainly fever and cough. The peak temperature of children was higher than that of adults (39.1 ± 0.7℃ vs 38.6 ± 0.7℃, p = 0.004). Elevated lactate dehydrogenase was more common in children than in adults (77.8% vs 11.3%, p < 0.001). Bronchial pneumonia and bilateral involvement were more common in children, while adults usually had unilateral involvement. Three (60%) adults and 21 (52.5%) children were macrolide-resistant Mycoplasma pneumoniae infected. Children were more likely to be co-infected (65.5% vs 22.8%, p < .001). Macrolides were used in most children and quinolones were used in most adults. Ten (18.2%) children were diagnosed with severe Mycoplasma pneumoniae pneumonia, whereas all adults had mild disease. Children had a significantly longer fever duration than adults ((5.6 ± 2.2) days vs (4.1 ± 2.2) days, p = 0.002). No patient required mechanical ventilation or died.

CONCLUSIONS

Mycoplasma pneumoniae infection shows a familial clustering epidemic trend at the turn of summer and autumn, with different clinical characteristics between parents and children.

Mycoplasma pneumoniae carriage in children with recurrent respiratory tract infections is associated with a less diverse and altered microbiota

BACKGROUND

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia in school-aged children and can be preceded by asymptomatic carriage. However, its role in recurrent respiratory tract infections is unclear. We studied the prevalence of M.pneumoniae carriage in children with recurrent respiratory infections and identified associated factors.

METHODS

We tested M.pneumoniae carriage by qPCR in children with recurrent infections and their healthy family members in a cross-sectional study. Serum and mucosal total and M.pneumoniae-specific antibody levels were measured by ELISA and nasopharyngeal microbiota composition was characterized by 16S-rRNA sequencing.

FINDINGS

Prevalence of M.pneumoniae carriage was higher in children with recurrent infections (68%) than their family members without infections (47% in siblings and 27% in parents). M.pneumoniae carriage among family members appeared to be associated with transmission within the household, likely originating from the affected child. In logistic regression corrected for age and multiple comparisons, IgA (OR 0.16 [0.06-0.37]) and total IgG deficiency (OR 0.15 [0.02-0.74]) were less prevalent in M.pneumoniae carriers (n = 78) compared to non-carriers (n = 36). In multivariable analysis, the nasopharyngeal microbiota of M.pneumoniae carriers had lower alpha diversity (OR 0.27 [0.09-0.67]) and a higher abundance of Haemophilus influenzae (OR 45.01 [2.74-1608.11]) compared to non-carriers.

INTERPRETATION

M.pneumoniae carriage is highly prevalent in children with recurrent infections and carriers have a less diverse microbiota with an overrepresentation of disease-associated microbiota members compared to non-carriers. Given the high prevalence of M.pneumoniae carriage and the strong association with H. influenzae, we recommend appropriate antibiotic coverage of M.pneumoniae and H. influenzae in case of suspected pneumonia in children with recurrent respiratory tract infections or their family members.

FUNDING

Wilhelmina Children's Hospital Research Fund, 'Christine Bader Stichting Irene KinderZiekenhuis', Sophia Scientific Research Foundation, ESPID Fellowship funded by Seqirus, Hypatia Fellowship funded by Radboudumc and The Netherlands Organisation for Health Research and Development (ZonMW VENI grant to LM Verhagen).

Atypical Pathogens in Adult Community-Acquired Pneumonia and Implications for Empiric Antibiotic Treatment: A Narrative Review

Atypical pathogens are intracellular bacteria causing community-acquired pneumonia (CAP) in a significant minority of patients. Legionella spp., Chlamydia pneumoniae and psittaci, Mycoplasma pneumoniae, and Coxiella burnetii are commonly included in this category. M. pneumoniae is present in 5-8% of CAP, being the second most frequent pathogen after Streptococcus pneumoniae. Legionella pneumophila is found in 3-5% of inpatients. Chlamydia spp. and Coxiella burnetii are present in less than 1% of patients. Legionella longbeachae is relatively frequent in New Zealand and Australia and might also be present in other parts of the world. Uncertainty remains on the prevalence of atypical pathogens, due to limitations in diagnostic means and methodological issues in epidemiological studies. Despite differences between CAP caused by typical and atypical pathogens, the clinical presentation alone does not allow accurate discrimination. Hence, antibiotics active against atypical pathogens (macrolides, tetracyclines and fluoroquinolones) should be included in the empiric antibiotic treatment of all patients with severe CAP. For patients with milder disease, evidence is lacking and recommendations differ between guidelines. Use of clinical prediction rules to identify patients most likely to be infected with atypical pathogens, and strategies of narrowing the antibiotic spectrum according to initial microbiologic investigations, should be the focus of future investigations.

Mycoplasma pneumoniae among Hospitalized Patients with Acute Respiratory Tract Infections in an Indian Tertiary Care Hospital: an Underreported Health Problem

The epidemiology of Mycoplasma pneumoniae (Mp) is poorly understood in India. The present study was conducted to identify the prevalence of Mp in a large set of patients with acute respiratory tract infections (ARI) in an Indian tertiary hospital. During 2015-2020, we tested throat swab specimens from patients with the clinical diagnosis of ARI (n = 1,098) by a real-time PCR and compared the demographic, clinical, laboratory, and outcome data of Mp-positive and Mp-negative patients. During the study period, 5% (55/1,098) of the tested samples were positive for Mp by PCR. School-aged children and young adults represented 36% (20/55) of the cases and 47.3% (26/55) of the cases were registered during the summer and monsoon. Among the Mp-positive patients, 61.8% (34/55) had underlying conditions; the most common were malignancy (n = 12; 21.8%) and hypertension (n = 6; 10.9%). Fever (98.2% versus 84.9%; P = 0.006), and pharyngitis (27.3% versus 16.3%; P = 0.034) were significantly common in the Mp-positive group than Mp-negative group. Among the Mp-positive group, 20% (11/55) of patients were admitted to an intensive care unit and a total of 7/55 (12.7%) patients received ventilatory support. The mortality in the Mp-positive cohort was 13.3%. The study provides baseline data regarding Mp prevalence and clinical characteristics. The application of molecular assays for diagnosing this pathogen among hospitalized patients with ARI could reduce inappropriate empirical antibiotic treatment and improve patient outcomes. Further large-scale studies are required to avoid the underdiagnosis of Mp infections in India and such studies should address some research gaps, such as macrolide resistance and molecular typing. IMPORTANCE M. pneumoniae (Mp) is a significant pathogen causing atypical pneumonia but by far these infections are underreported clinical entities in India. In the present study, we report the prevalence of Mp and describe the demographic and baseline clinical data of Mp-positive cases in an Indian tertiary care hospital. Our study may improve the clinician's awareness of this important agent of respiratory infection therefore timely and accurate diagnostic tools can be applied for patient management decisions and outcomes.

Mycoplasma pneumoniae multilocus variable-number tandem-repeat analysis genotypes are associated with inflammatory biomarker levels in children with lower respiratory tract infections

The multilocus variable-number tandem-repeat analysis (MLVA) typing method is commonly used in Mycoplasma pneumoniae (M. pneumoniae) epidemiology. It remains unknown if clinical manifestations of lower respiratory tract infections (LRTI) in children differ between different MLVA genotypes. We aimed to determine if specific M. pneumoniae MLVA genotypes indicate the severity of LRTI in children. We performed a retrospective study of children younger than 18 years with signs of acute M. pneumoniae LRTI from January 1, 2009, to December 31, 2014. All patients who were PCR-positive for M. pneumoniae from pharyngeal swabs and had MLVA genotype successfully defined were included in the study. We compared the epidemiological and clinical data of children infected with different MLVA genotypes. In total, 429 patients (mean age 7.4 years, SD 3.4 years; 54% boys) met the study inclusion criteria. We compared the data of patients infected with the three most common MLVA types: MLVA-3,5,6,2 (86/429), MLVA-3,6,6,2 (71/429) and MLVA-4,5,7,2 (256/429). MLVA-3,5,6,2-infected patients over 5 years of age presented with a significantly higher median C-reactive protein level (34 vs 23 vs 19 mg/L, p = .008) and a higher median white blood cell count (9.4 vs 7.9 vs 8.5 × 10⁹/L, p = .040) compared to MLVA-3,6,6,2- and MLVA-4,5,7,2-infected patients. No such difference was observed in the group of younger than 5 years. The results from our large cohort indicate that different MLVA genotypes may have different pathogenic potential and that children with MLVA-3,5,6,2 LRTI may present with higher inflammatory marker levels in comparison with other MLVA types.

Performance Analysis of Novel Nucleic Acid Detection Kit for Mycoplasma pneumoniae

Respiratory tract infections caused by Mycoplasma pneumoniae is a serious risk for child health. It has been difficult to prevent and control for a variety of reasons; therefore, timely diagnosis is particularly important for treatment of patients. At present, the rapid M pneumoniae test kits based on nucleic acid amplification have been commercialized and used as primary diagnostic tools for M pneumoniae infection, but current kits are time-consuming, which is difficult to meet the requirement for accurate and rapid diagnosis of M pneumoniae during epidemics. Rapid and accurate test kits are urgently required to diagnose M pneumoniae infection. In this article, we evaluated the performance of a novel nucleic acid detection kit (A) for M pneumoniae from feasibility and sensitivity, and compared it with kit B. Results showed this kit has the advantage of being rapid, sensitive, and specific, which meets the demands for the diagnosis of M pneumoniae infection in clinical settings.

Community-Acquired Respiratory Distress Syndrome Toxin: Unique Exotoxin for M. pneumoniae

Mycoplasma pneumoniae infection often causes respiratory diseases in humans, particularly in children and adults with atypical pneumonia and community-acquired pneumonia (CAP), and is often exacerbated by co-infection with other lung diseases, such as asthma, bronchitis, and chronic obstructive pulmonary disorder. Community-acquired respiratory distress syndrome toxin (CARDS TX) is the only exotoxin produced by M. pneumoniae and has been extensively studied for its ADP-ribosyltransferase (ADPRT) activity and cellular vacuolization properties. Additionally, CARDS TX induces inflammatory responses, resulting in cell swelling, nuclear lysis, mucus proliferation, and cell vacuolization. CARDS TX enters host cells by binding to the host receptor and is then reverse transported to the endoplasmic reticulum to exert its pathogenic effects. In this review, we focus on the structural characteristics, functional activity, distribution and receptors, mechanism of cell entry, and inflammatory response of CARDS TX was examined. Overall, the findings of this review provide a theoretical basis for further investigation of the mechanism of M. pneumoniae infection and the development of clinical diagnosis and vaccines.

A Study Based on Metabolomics, Network Pharmacology, and Experimental Verification to Explore the Mechanism of Qinbaiqingfei Concentrated Pills in the treatment of Mycoplasma Pneumonia

Qinbaiqingfei concentrated pills (QB) are a commonly used medicine for the treatment of mycoplasma pneumonia in China, and the mechanism of action of QB needs to be studied further. Therefore, we use a combination of metabolomics and network pharmacology to clarify the mechanism of QB. Nontarget metabolomics studies were performed on rat serum, urine, and lung tissues, and 56 therapeutic biomarkers were found. Subsequently, the components of QB absorbed into the blood and lung tissues were clarified, and based on this finding, the core target of network pharmacology was predicted. The enrichment analysis of biomarkers–genes finally confirmed their close relationship with the NF-κB signaling pathway. By western blotting expression of the proteins in the lung tissue–related signaling pathways, it is finally confirmed that QB inhibits the NF-κB signaling pathway through SIRT1, IL-10 and MMP9, CTNNB1, EGFR, and other targets. It plays a role in regulating immunity, regulating metabolism, and treating diseases.

Mycoplasma pneumoniae carriage evades induction of protective mucosal antibodies

Background

Mycoplasma pneumoniae is the most common bacterial cause of pneumonia in children hospitalised for community-acquired pneumonia (CAP). Prevention of infection by vaccines may be an important strategy in the presence of emerging macrolide-resistant M. pneumoniae. However, knowledge of immune responses to M. pneumoniae is limited, complicating vaccine design.

Methods

We studied the antibody response during M. pneumoniae respiratory tract infection and asymptomatic carriage in two different cohorts.

Results

In a nested case–control study (n=80) of M. pneumoniae carriers and matched controls we observed that carriage by M. pneumoniae does not lead to a rise in either mucosal or systemic M. pneumoniae-specific antibodies, even after months of persistent carriage. We replicated this finding in a second cohort (n=69) and also found that during M. pneumoniae CAP, mucosal levels of M. pneumoniae-specific IgA and IgG did increase significantly. In vitro adhesion assays revealed that high levels of M. pneumoniae-specific antibodies in nasal secretions of paediatric patients prevented the adhesion of M. pneumoniae to respiratory epithelial cells.

Conclusions

Our study demonstrates that M. pneumoniae-specific mucosal antibodies protect against bacterial adhesion to respiratory epithelial cells, and are induced only during M. pneumoniae infection and not during asymptomatic carriage. This is strikingly different from carriage with bacteria such as Streptococcus pneumoniae where mucosal antibodies are induced by bacterial carriage.

Antibodies against M. pneumoniae, the most common bacterial cause of pneumonia in children, are able to prevent adhesion of M. pneumoniae to epithelial cells, but are only induced during infection and not during asymptomatic carriagehttps://bit.ly/3CNdAhM

Mycoplasma pneumoniae P1 Genotype Indicates Severity of Lower Respiratory Tract Infections in Children

Mycoplasma pneumoniae strains can be classified into two major genetic groups, P1 type 1 (P1-1) and P1 type 2 (P1-2). It remains unknown if clinical manifestations of lower respiratory tract infections (LRTI) in children differ between the two genotypes. We aimed to determine if the M. pneumoniae P1 genotype is associated with severity of LRTI in children. Medical charts of 420 children (≤15 years old) with signs of acute LRTI who were PCR positive for M. pneumoniae from pharyngeal swabs in a recent M. pneumoniae epidemic were analyzed. We used a culture and pyrosequencing approach for genotyping PCR-positive samples. We compared epidemiological and clinical data of children with either P1-1 or P1-2 LRTI. P1-2-infected children presented with a significantly higher median baseline C-reactive protein level and were admitted to the hospital more often. The P1 genotype had a significant predictive value in a multiple linear regression model predicting C-reactive protein levels in our study sample. Moreover, the P1 genotype significantly affected the likelihood of hospital admission in a logistic regression model. Our modeling results were also confirmed on an additional independent sample of children with M. pneumoniae LRTI. Results from our large patient group indicate that the two M. pneumoniae P1 genotypes may have different pathogenic potential and that LRTI with P1-2 strains may have a more severe disease course than those with P1-1 strains in children. P1 genotyping is not routinely performed but could be used as a predictor of M. pneumoniae LRTI severity, enabling patient-tailored treatments.

Mycoplasma pneumoniae Genotypes and Clinical Outcome in Children

Factors leading to the wide range of manifestations associated with Mycoplasma pneumoniae infection are unclear. We investigated whether M. pneumoniae genotypes are associated with specific clinical outcomes. We compared M. pneumoniae loads and genotypes of children with mucocutaneous disease to those of children with pneumonia, family members with upper respiratory tract infection (URTI), and carriers from a prospective cohort study (n = 47; 2016 to 2017) and to those of other children with mucocutaneous disease from a case series (n = 7; 2017 to 2020). Genotyping was performed using macrolide resistance determination, P1 subtyping, multilocus variable-number tandem-repeat analysis (MLVA), and multilocus sequence typing (MLST). Comparisons were performed with a pairwise Wilcoxon rank sum test and a Fisher exact test with corrections for multiple testing, as appropriate. M. pneumoniae loads did not statistically differ between patients with mucocutaneous disease and those with pneumonia or carriers. Macrolide resistance was detected in 1 (1.9%) patient with mucocutaneous disease. MLVA types from 2016 to 2017 included 3-5-6-2 (n = 21 [46.7%]), 3-6-6-2 (n = 2 [4.4%]), 4-5-7-2 (n = 14 [31.1%]), and 4-5-7-3 (n = 8 [17.8%]), and they correlated with P1 subtypes and MLST types. MLVA types were not associated with specific outcomes such as mucocutaneous disease, pneumonia, URTI, or carriage. They were almost identical within families but varied over geographic location. MLVA types in patients with mucocutaneous disease differed between 2016 to 2017 (3-5-6-2, n = 5 [62.5%]) and 2017 to 2020 (4-5-7-2, n = 5 [71.4%]) (P = 0.02). Our results suggest that M. pneumoniae genotypes may not determine specific clinical outcomes.

Prediction model for prolonged fever in patients with Mycoplasma pneumoniae pneumonia: a retrospective study of 716 pediatric patients

Objective

To identify patients with Mycoplasma pneumoniae pneumonia (MPP) with a risk of prolonged fever while on macrolides.

Methods

A retrospective study was performed with 716 children admitted for MPP. Refractory MPP (RMPP-3) was defined as fever persisting for > 72 h without improvement in clinical and radiologic findings after macrolide antibiotics (RMPP-3) or when fever persisted for > 120 h (RMPP-5) without improvement in clinical and radiologic findings. Radiological data, laboratory data, and fever profiles were compared between the RMPP and non-RMPP groups. Fever profiles included the highest temperature, lowest temperature, and frequency of fever. Prediction models for RMPP were created using the logistic regression method and deep neural network. Their predictive values were compared using receiver operating characteristic curves.

Results

Overall, 716 patients were randomly divided into two groups: training and test cohorts for both RMPP-3 and RMPP-5. For the prediction of RMPP-3, a conventional logistic model with radiologic grouping showed increased sensitivity (63.3%) than the model using laboratory values. Adding laboratory values in the prediction model using radiologic grouping did not contribute to a meaningful increase in sensitivity (64.6%). For the prediction of RMPP-5, laboratory values or radiologic grouping showed lower sensitivities ranging from 12.9 to 16.1%. However, prediction models using predefined fever profiles showed significantly increased sensitivity for predicting RMPP-5, and neural network models using 12 sequential fever data showed a greatly increased sensitivity (64.5%).

Conclusion

RMPP-5 could not be effectively predicted using initial laboratory and radiologic data, which were previously reported to be predictive. Further studies using advanced mathematical models, based on large-sized easily accessible clinical data, are anticipated for predicting RMPP.

A comparison of efficacy and safety of complementary and alternative therapies for severe mycoplasma pneumonia in children: A protocol for systematic review and meta-analysis

BACKGROUND

In recent years, the incidence rate of children with severe Mycoplasma pneumoniae pneumonia (SMPP) is increasing, which poses a great threat to children's life and safety. There are some limitations in the existing drugs for the treatment of SMPP, and the supplementary and alternative therapy of SMPP plays an irreplaceable role in the treatment of this disease. This study will evaluate the efficacy and safety of various complementary and alternative therapies for SMPP by means of mesh meta-analysis. In order to provide the basis for clinical rational use.

METHODS

Two researchers will independently and comprehensively searched the Cochrane Central controlled trials registry, Cochrane Library, PubMed, web of science, EMBASE, CNKI, and Wanfang database to collect randomized controlled trials (RCT) studies on complementary and alternative therapies for SMPP. And the relevant references included in the systematic review/meta-analysis are screened. The retrieval time limit is from the establishment of the database to November 2020. We will use Revman 5.3 software for meta-analysis and use grade to grade the quality of evidence in the net meta-analysis (NMA).

RESULTS

The aim of this study was to compare the efficacy and safety of different complementary and alternative therapies in the treatment of SMPP, with a view to evaluating and ranking different interventions.

CONCLUSION

The supplement and replacement therapy of SMPP can improve the clinical efficacy, relieve the clinical symptoms, improve the quality of life of children, and reduce adverse reactions, which can provide strong support for the rational use of clinicians.

INPLASY REGISTRATION NUMBER

INPLASY2020110079.

Acute respiratory distress syndrome during the COVID-19 pandemic: not only SARS-CoV-2

A previously healthy 30-year-old woman developed severe ARDS at the beginning of the COVID-19 pandemic. SARS-CoV-2 infection was suspected, but testing was negative. Mycoplasma pneumoniae was detected by PCR in bronchoalveolar lavage fluid and blood. This case illustrates that M. pneumoniae infection can progress to septicemia and ARDS with severe respiratory failure in young healthy adults.

Explore the Predictive Value of Peripheral Blood Cell Parameters in Refractory Mycoplasma pneumoniae Pneumonia in Children Over 6 Years Old

Background: To determine the predictive value of peripheral blood cell parameters for refractory Mycoplasma pneumoniae pneumonia (RMPP) in children over 6 years old. Methods: A retrospective study was conducted in children with RMPP admitted to the respiratory department of Tianjin Children's Hospital from September 2017 to September 2019, and non-refractory Mycoplasma pneumoniae pneumonia (NRMPP) was selected by the propensity score method and matched according to the ratio of 1:1.5. We analyzed the differences in clinical characteristics, peripheral blood cell parameters, imaging findings, and treatments between the two groups, and further determined the predictive value of peripheral blood cell parameters on RMPP. Results: There were 76 patients in the RMPP group and 114 patients in the NRMPP group. We found that the RMPP group has a longer clinical course and a higher incidence of intrapulmonary and extrapulmonary complications (p < 0.01). Moreover, the proportion of children in the RMPP group who received immunotherapy (such as glucocorticoid, gamma immunoglobulin) and fiberoptic bronchoscopy intervention was higher than that in the NRMPP group (p < 0.01). Meanwhile, the level of neutrophil, neutrophil/lymphocyte ratio (NLR), platelet count/lymphocyte ratio (PLR), mean platelet volume/lymphocyte ratio (MPVLR), C-reactive protein (CRP), lactic dehydrogenase (LDH), and interleukin (IL)-6 in the RMPP group was significantly higher (p < 0.01) than those in the NRMPP group. The incidence of pulmonary consolidation, atelectasis, and pleural effusion was also higher in the RMPP group (p < 0.05). ROC curve and binary logistic regression analysis showed that NLR > 3.92 (OR = 3.243; 95% CI = 1.485-7.081; p = 0.003), MPVLR > 5.29 (OR = 2.700; 95% CI = 1.258-5.795; p = 0.011), and pleural effusion (OR = 3.023; 95% CI = 1.424-6.420; p = 0.004) were significant factors in predicting RMPP. Our study showed that NLR had higher accuracy in predicting RMPP than CRP. Conclusions: The parameters of peripheral blood cells might be a predictor of RMPP. NLR > 3.92, MPVLR > 5.29, and pleural effusion might have important predictive value for RMPP in children over 6 years old.

Case Report: Clinical Analysis of Fulminant Mycoplasma pneumoniae Pneumonia in Children

Fulminant Mycoplasma pneumoniae pneumonia (FMPP) accounts for 0.5-2% of all MPP cases, which is considered as MPP combined with severe complications such as hypoxemia, acute respiratory distress syndrome, or acute respiratory failure. It primarily affects young adults with no underlying disease. Although some studies have proved the severity of FMPP, the details about clinical diagnosis and treatment of FMPP in children have been rarely reported. In this case study, we described three cases who suffered from FMPP. These children not only developed acute lung injury and multiple organ involvement within 7 days of treatment, but were also found plastic bronchitis by bronchoscopy. Finally, all the patients were treated successfully with azithromycin, glucocorticoid, and bronchoscopy lavage. We conclude that this case study would contribute to raise awareness with respect to FMPP, which may occur at a younger age with faster disease progression and common extrapulmonary manifestations. It also reinforces the importance of early identification and prompt intervention to save life of children and reduces sequelae. Further studies are needed about mechanism of FMPP.

Improved Diagnostics Help to Identify Clinical Features and Biomarkers That Predict Mycoplasma pneumoniae Community-acquired Pneumonia in Children

BACKGROUND

There are no reliable signs or symptoms that differentiate Mycoplasma pneumoniae (Mp) infection in community-acquired pneumonia (CAP) from other etiologies. Additionally, current diagnostic tests do not reliably distinguish between Mp infection and carriage. We previously determined that the measurement of Mp-specific immunoglobulin M antibody-secreting cells (ASCs) by enzyme-linked immunospot assay allowed for differentiation between infection and carriage. Using this new diagnostic test, we aimed to identify clinical and laboratory features associated with Mp infection.

METHODS

This is a prospective cohort study of children, 3-18 years of age, with CAP from 2016 to 2017. Clinical features and biomarkers were compared between Mp-positive and -negative groups by Mann-Whitney U test or Fisher exact test, as appropriate. Area under the receiver operating characteristic curve (AUC) differences and optimal thresholds were determined by using the DeLong test and Youden J statistic, respectively.

RESULTS

Of 63 CAP patients, 29 were Mp-positive (46%). Mp positivity was statistically associated with older age (median, 8.6 vs 4.7 years), no underlying disease, family with respiratory symptoms, prior antibiotic treatment, prolonged prodromal respiratory symptoms and fever, and extrapulmonary (skin) manifestations. Lower levels of C-reactive protein, white blood cell count, absolute neutrophil count, and procalcitonin (PCT), specifically PCT <0.25 μg/L, were statistically associated with Mp infection. A combination of age >5 years (AUC = 0.77), prodromal fever and respiratory symptoms >6 days (AUC = 0.79), and PCT <0.25 μg/L (AUC = 0.81) improved diagnostic performance (AUC = 0.90) (P = .05).

CONCLUSIONS

A combination of clinical features and biomarkers may aid physicians in identifying patients at high risk for Mp CAP.

Correlation between Preventive Health Behaviors and Psycho-Social Health Based on the Leisure Activities of South Koreans in the COVID-19 Crisis

COVID-19 has caused unprecedented damage worldwide, and quarantine and lockdown measures have been undertaken globally. This study focused on the differences in preventive behaviors and psycho-social health of South Koreans, as people continue engaging in leisure activities under self-regulation without a lockdown measure imposed by the government. For the sample, the frame of the “2018 Population and Housing Census” in South Korea was applied, and data from 1770 people were analyzed. The results showed that the groups participating in culture and arts and social activities displayed characteristics with high prevention. Additionally, the groups that continued leisure activities for more than five years and with family showed high preventive behaviors. Meanwhile, participation in leisure activities with friends of the opposite sex lowered preventive behavior. In terms of psycho-social health, all groups were affiliated to the potential stress group and there were no differences in the period and participation time for leisure activities. Furthermore, the group participating in leisure activities with their school and group experienced psychological stability. When lockdown measures are eased, the aforementioned characteristics should be considered to design government policy; they can also be used as a reference for public health in case of a future outbreak of an epidemic.

The Clinical Presentation of Pediatric Mycoplasma pneumoniae Infections-A Single Center Cohort

BACKGROUND

Mycoplasma pneumoniae (MP) is a major cause of community-acquired upper and lower respiratory infections in school-age children; however, there is increasing recognition that younger children are also affected. Clinical manifestations vary from asymptomatic, to severe complicated pneumonia sometimes with extrapulmonary manifestations.

METHODS

We reviewed the medical records of all MP positive pediatric patients admitted to the Hadassah-Hebrew University Medical Center. MP positive case was defined if MP polymerase chain reaction was positive from an oropharyngeal swab sent from 2007 to 2017.

RESULTS

During the study period, we identified 353 MP positive pediatric cases, of which 51.3% (181 of 353) were younger than 6 years old. Full clinical data were available for 332 of 353 (94%). The median age was 5.7 years (range, 3 weeks to 18 years). Disease presentation differed between younger and older children. Children older than 6 years were more likely to have chest radiograph confirmed pneumonia (66% vs. 52%; P = 0.009), while younger children were more likely to have other respiratory manifestations (37% vs. 25%; P = 0.017). The duration of hospitalization and pediatric intensive care unit admission rate, however, did not differ between age groups. The rate of extrapulmonary manifestations were also similar.

CONCLUSIONS

MP-associated infection is a significant cause of hospitalization in the pediatric population including younger children (<6 years old). However, the clinical presentation in younger age is less typical than is thought. These findings should prompt clinicians to consider MP infections also in children younger than 6 admitted with fever even without pneumonia.

Disulfide bond of Mycoplasma pneumoniae community-acquired respiratory distress syndrome toxin is essential to maintain the ADP-ribosylating and vacuolating activities

Mycoplasma pneumoniae is the leading cause of bacterial community-acquired pneumonia among hospitalised children in United States and worldwide. Community-acquired respiratory distress syndrome (CARDS) toxin is a key virulence determinant of M. pneumoniae. The N-terminus of CARDS toxin exhibits ADP-ribosyltransferase (ADPRT) activity, and the C-terminus possesses binding and vacuolating activities. Thiol-trapping experiments of wild-type (WT) and cysteine-to-serine-mutated CARDS toxins with alkylating agents identified disulfide bond formation at the amino terminal cysteine residues C230 and C247. Compared with WT and other mutant toxins, C247S was unstable and unusable for comparative studies. Although there were no significant variations in binding, entry, and retrograde trafficking patterns of WT and mutated toxins, C230S did not elicit vacuole formation in intoxicated cells. In addition, the ADPRT domain of C230S was more sensitive to all tested proteases when compared with WT toxin. Despite its in vitro ADPRT activity, the reduction of C230S CARDS toxin-mediated ADPRT activity-associated IL-1β production in U937 cells and the recovery of vacuolating activity in the protease-released carboxy region of C230S indicated that the disulfide bond was essential not only to maintain the conformational stability of CARDS toxin but also to properly execute its cytopathic effects.

Detection of Mycoplasma pneumoniae in Mexican children with community-acquired pneumonia: experience in a tertiary care hospital

Purpose: Mycoplasma pneumoniae is an important cause of community-acquired pneumonia (CAP). Information on the prevalence of M. pneumoniae in pediatric patients with CAP in Mexico is limited. The aim of this study was to detect M. pneumoniae in hospitalized pediatric patients with CAP. Patients and methods: We performed a descriptive study in a tertiary-level pediatric reference center, obtaining 154 respiratory samples from patients under 18 years of age and diagnosed with CAP. M. pneumoniae was detected by real-time polymerase chain reaction (PCR) targeting the p1 and CARDS genes. Complete blood cell count, measurement of C-reactive protein and detection of IgM and IgG anti-P1 were performed. Clinical, epidemiological and radiological data of the patients were analyzed. Results: M. pneumoniae was detected by real-time PCR in 26.6% of the samples. 39% of the cases occurred during the spring season. A total of 83% of the patients with M. pneumoniae had some underlying disease; renal disease, autoimmune disease and primary immunodeficiencies had a significant association with M. pneumoniae CAP. Children under 6 years of age represented 53.7% of the cases. Fever and cough were the most frequent symptoms. IgM and IgG were positive in 1.9% and 14% of the patients, respectively. In the chest X-ray, 17.1% of the patients showed multifocal alveolar infiltrates pattern. The complications in this series were 26.8%. The mortality in this study was 4.9%. Conclusion: This is the first report in Mexico about M. pneumoniae as a causal agent of CAP in a tertiary care pediatric hospital using real-time PCR and serology. M. pneumoniae was responsible for 26.6% of the cases and was frequent in children under 6 years of age. In addition, we described the clinical presentation in patients with underlying diseases.

Mycoplasma pneumoniae in pediatric patients: Do macrolide-resistance and/or delayed treatment matter?

BACKGROUND

Mycoplasma pneumoniae is a common pathogen for pneumonia in children, especially in the post-pneumococcal conjugate vaccination era. Though self-limited disease was found in the majority of the patients, severe diseases occurred occasionally. The emergence of macrolide resistance was reported worldwide. It is important to delineate whether macrolide resistance or delayed treatment affects outcome.

METHODS

We retrospectively collected pediatric patients with M. pneumoniae infection confirmed by positive PCR in a tertiary medical center in Taiwan from 2010 to 2017. Patients' clinical characteristics, bacterial load, macrolide resistance and treatment outcome were analyzed.

RESULTS

Among 471 children with positive M. pneumoniae PCR, 95% were diagnosed with pneumonia. Seventeen percent of patients had extrapulmonary complications, and 1.5% had respiratory failure. Delayed treatment was associated with prolonged fever after appropriate treatment, fulminant disease, and extrapulmonary manifestations (p < 0.05). The mean rate of macrolide resistance was 24% and macrolide resistance was related to longer febrile duration, longer hospital stay, lung consolidation and impaired liver function tests (P < 0.05).

CONCLUSIONS

Macrolide resistance was fairly common and might lead to delayed appropriate antibiotic treatment. Delayed appropriate antimicrobial treatment, no matter macrolide resistance or not, was associated with more severe and/or prolonged diseases. Early diagnosis of M. pneumoniae as well as the awareness of macrolide resistance make early effective antibiotic treatment possible and may improve clinical outcomes.

Contribution of Co-detected Respiratory Viruses and Patient Age to the Clinical Manifestations of Mycoplasma Pneumoniae Pneumonia in Children

BACKGROUND

The clinical spectrum of Mycoplasma pneumoniae pneumonia is widely variable. This study evaluated the clinical manifestations of M. pneumoniae pneumonia in children of different age groups and by the presence of co-detected respiratory virus.

METHODS

This study included children hospitalized with M. pneumoniae pneumonia between 2010 and 2015. At the time of pneumonia diagnosis, a nasopharyngeal aspirate was analyzed for respiratory viruses by reverse transcription-polymerase chain reaction (RT-PCR). The clinical manifestations and laboratory findings were reviewed from medical records.

RESULTS

Of the 286 children with M. pneumoniae pneumonia, 84 (29.4%) had a co-detected respiratory virus, with the highest co-detection rate in young children (51.9% of children <2 years; P = 0.002). In children <2 years, with and without co-detected virus, wheezing occurred in 35.7% and 15.4%, respectively. Among the 202 children without any virus detected, only 6.4% were <2 years. These young children showed fewer median days of fever than the children ≥2 years (8 vs. 11 days; P = 0.022). Children ≥2 years tended to have accompanying skin rashes (21.7% vs.7.7%; P = 0.310) and elevated liver enzymes (21.7% vs. 0%; P = 0.075) more frequently than children <2 years. Only 53.8% of the patients <2 years were treated with macrolide compared with 94.1% of the patients ≥2 years (P < 0.001).

CONCLUSIONS

The clinical manifestations of M. pneumoniae pneumonia in young children are milder than those in older children. A high prevalence of co-detected respiratory virus in young children suggests that virus might play a role in making pneumonia clinically apparent in this age group.

Clinical characteristics from co-infection with avian influenza A H7N9 and Mycoplasma pneumoniae: a case report

Background

More and more cases of human infections with avian influenza A H7N9 have been reported since it was first mentioned in 2013 in China, but concurrence of influenza A H7N9 with Mycoplasma pneumoniae, however, has never been described. Here, we reported the case of a woman co-infected by influenza A H7N9 and Mycoplasma pneumoniae, whose treatment process was a little bit longer and a little bit complicated as well.

Case presentation

Our patient was an 80-year-old Chinese woman who presented with fever, cough, chest tightness, and shortness of breath. A computed tomography scan showed obvious infiltrations at lower parts of both lungs. Arterial blood gas analysis confirmed a severe respiratory failure (type I). Her sputum and throat swabs were checked for nucleic acid of influenza A and the result was positive for influenza A H7N9. She was diagnosed as having severe influenza A H7N9 and acute respiratory distress syndrome, and was admitted to an intensive care unit. She was given comprehensive treatment, including oseltamivir, methylprednisolone, immunoglobulin, gastric protection, and noninvasive mechanical ventilation. Her condition improved 4 days later. However, some symptoms exacerbated again 2 days later with ground-glass changes appearing in upper area of right lung and the titer of antibody to Mycoplasma pneumoniae rising from 1:80 to 1:640. She was reasonably considered to be infected with Mycoplasma pneumoniae as well, and azithromycin and moxifloxacin were added to her treatment. Oseltamivir was discontinued because of three consecutive negative results of nucleic acid for influenza A H7N9, but anti-Mycoplasma treatment was continued. Although her symptoms and abnormal changes on computed tomography scan slowly went away, she finally recovered from the mixed infection after a total of 33 days of management.

Conclusion

In patients with confirmed influenza A H7N9 infection whose condition worsens again, especially with new infiltration or lung ground-glass infiltration, one should suspect infection by other pathogens such as Mycoplasma pneumoniae.

Mycoplasma pneumoniae Community-Acquired Respiratory Distress Syndrome Toxin Uses a Novel KELED Sequence for Retrograde Transport and Subsequent Cytotoxicity

Mycoplasma pneumoniae is an atypical bacterium that causes respiratory illnesses in humans, including pharyngitis, tracheobronchitis, and community-acquired pneumonia (CAP). It has also been directly linked to reactive airway disease, asthma, and extrapulmonary pathologies. During its colonization, M. pneumoniae expresses a unique ADP-ribosylating and vacuolating cytotoxin designated community-acquired respiratory distress syndrome (CARDS) toxin. CARDS toxin persists and localizes in the airway in CAP patients, asthmatics, and trauma patients with ventilator-associated pneumonia. Although CARDS toxin binds to specific cellular receptors, is internalized, and induces hyperinflammation, histopathology, mucus hyperplasia, and other airway injury, the intracellular trafficking of CARDS toxin remains unclear. Here, we show that CARDS toxin translocates through early and late endosomes and the Golgi complex and concentrates at the perinuclear region to reach the endoplasmic reticulum (ER). Using ER-targeted SNAP-tag, we confirmed the association of CARDS toxin with the ER and determined that CARDS toxin follows the retrograde pathway. In addition, we identified a novel CARDS toxin amino acid fingerprint, KELED, that is required for toxin transport to the ER and subsequent toxin-mediated cytotoxicity.IMPORTANCEMycoplasma pneumoniae, a leading cause of bacterial community-acquired pneumonia (CAP) among children and adults in the United States, synthesizes a 591-amino-acid ADP-ribosylating and vacuolating protein, designated community-acquired respiratory distress syndrome (CARDS) toxin. CARDS toxin alone is sufficient to induce and mimic major inflammatory and histopathological phenotypes associated with M. pneumoniae infection in rodents and primates. In order to elicit its ADP-ribosylating and vacuolating activities, CARDS toxin must bind to host cell receptors, be internalized via clathrin-mediated pathways, and subsequently be transported to specific intracellular organelles. Here, we demonstrate how CARDS toxin utilizes its unique KELED sequence to exploit the retrograde pathway machinery to reach the endoplasmic reticulum (ER) and fulfill its cytopathic potential. The knowledge generated from these studies may provide important clues to understand the mode of action of CARDS toxin and develop interventions that reduce or eliminate M. pneumoniae-associated airway and extrapulmonary pathologies.

Low Bacterial Co-infection Invalidates the Early Use of Non-anti-Mycoplasma pneumoniae Antibiotics in Pediatric Refractory Mycoplasma pneumoniae Pneumonia Patients

Background: Childhood refractory mycoplasma pneumoniae (MP) pneumonia (RMPP) is a lung disease with elevated level of C-reactive protein and severe clinical and radiological deterioration. Whether bacterial co-infection contributes to disease of RMPP and whether inclusion of non-anti-MP antibiotics in treatment regimen would benefit RMPP patients remains elusive. Methods: We retrospectively reviewed the medical records of 675 RMPP children. Traditional bacterial culture and next generation sequencing (NGS) were used to detect bacteria in bronchoalveolar lavage fluid in all the 675 patients and 18 patients respectively. Antibiotics used and clinical outcomes were analyzed along with other clinical measurements. Results: Positive bacterial cultures were only found in 18 out of 675 cases (2.67%) and NGS analyses of another 18 cases did not revealed positive bacterial infection, which were consistent with the results of bacterial cultures. Non-anti-MP antibiotics were utilized in 630 cases (93.33%), even last-line antibiotics, such as glycopeptides or carbapenems, were frequently used. Conclusion: Bacterial co-infection in RMPP was rare and non-anti-MP antibiotics didn't show any efficacy for early treatment of RMPP patients, which may provide a rationale for restricting the use of non-anti-MP antibiotics in RMPP patients and preventing antibiotic resistance globally.

Adjunctive corticosteroid therapy for inpatients with Mycoplasma pneumoniae pneumonia

Background

There is conflicting evidence regarding the benefit of adjunctive corticosteroid therapy in patients with Mycoplasma pneumoniae pneumonia. We hypothesised that corticosteroid therapy could reduce mortality and length of stay (LOS) in such patients.

Methods

Adult patients with M. pneumoniae pneumonia from January 2010 to December 2013 were identified from the Japanese Diagnosis Procedure Combination inpatient database. The effects of low-dose and high-dose corticosteroid therapies on mortality, LOS, drug costs and hyperglycaemia requiring insulin treatment were evaluated using propensity score analyses.

Results

Eligible patients (n = 2228) from 630 hospitals were divided into no-corticosteroid (n = 1829), low-dose corticosteroid (n = 267) and high-dose corticosteroid (n = 132) groups. The propensity score-matched pairs were generated from no-corticoid and low-dose corticoid groups (251 pairs), or no-corticoid and high-dose corticosteroid groups (120 pairs). Adjunctive corticosteroid therapy did not decrease 30-day mortality. In addition, both low-dose and high-dose corticosteroid therapies were associated with increases in LOS. Furthermore, hyperglycaemia requiring insulin treatment and drug cost increased with corticosteroid use.

Conclusions

Adjunctive treatment with low-dose or high-dose corticosteroids may not be beneficial in M. pneumoniae pneumonia.

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.

Characterization and evaluation of a novel immunochromatographic assay for pharyngeal Mycoplasmapneumoniae ribosomal protein L7/L12 antigens

Point-of-care testing for Mycoplasma pneumoniae infection may be ideal and useful because significant numbers of the cases will be seen as outpatients. Recently, a new immunochromatographic method (ICM) targeting M. pneumoniae ribosomal protein L7/L12 (RP-L7/L12) in pharyngeal swabs became available in Japan, although clinical data and basic information regarding efficacy and characterization of this ICM are limited. The present study examined the fate of M. pneumoniae RP-L7/L12 during in vitro growth and the correlation between M. pneumoniae concentration in clinical specimens and the sensitivity of the ICM test. The usefulness of the ICM was investigated in patients suspected of having M. pneumoniae pneumonia and upper respiratory tract infection (137 children and 39 adults). The limit of detection for the ICM test was 1.1×104 c.f.u. ml-1 of M. pneumoniae. Bacterial production of RP-L7/L12 correlated positively with the viable M. pneumoniae concentration in vitro; antigen was then degraded in culture broth, with an in vitro half-life of approximately 2 days. Five other Mycoplasma spp. and 14 representative respiratory pathogens were ICM assay negative at bacterial concentrations of 106 c.f.u. ml-1. The clinical sensitivity and specificity of the ICM assay were 57.1 % (20/35) and 92.2 % (130/141), respectively, in comparison with bacterial culture. Clinical specimens containing ≥106 c.f.u. ml-1 of M. pneumoniae burden were ICM positive in 13 of 18 cases (72.2 %). The ICM is a poorly sensitive but reasonably specific means for detecting M. pneumoniae infections.

Acute respiratory distress syndrome caused by Mycoplasma pneumoniae without elevated pulmonary vascular permeability: a case report

Sporadic patients with acute respiratory distress syndrome (ARDS) caused by Mycoplasma pneumoniae have been reported. However, knowledge about the pathophysiology and pharmacological treatment of this condition is insufficient. Moreover, the pulmonary vascular permeability in ARDS related to M. pneumoniae infection has not been reported. We report a case of ARDS caused by Mycoplasma pneumoniae without elevated pulmonary vascular permeability, which was successfully treated using low-dose short-term hydrocortisone, suggesting that pulmonary infiltration in ARDS caused by Mycoplasma pneumoniae does not match the criteria of permeability edema observed in typical ARDS.

Infection with and Carriage of Mycoplasma pneumoniae in Children

“Atypical” pneumonia was described as a distinct and mild form of community-acquired pneumonia (CAP) already before Mycoplasma pneumoniae had been discovered and recognized as its cause. M. pneumoniae is detected in CAP patients most frequently among school-aged children from 5 to 15 years of age, with a decline after adolescence and tapering off in adulthood. Detection rates by polymerase chain reaction (PCR) or serology in children with CAP admitted to the hospital amount 4–39%. Although the infection is generally mild and self-limiting, patients of every age can develop severe or extrapulmonary disease. Recent studies indicate that high rates of healthy children carry M. pneumoniae in the upper respiratory tract and that current diagnostic PCR or serology cannot discriminate between M. pneumoniae infection and carriage. Further, symptoms and radiologic features are not specific for M. pneumoniae infection. Thus, patients may be unnecessarily treated with antimicrobials against M. pneumoniae. Macrolides are the first-line antibiotics for this entity in children younger than 8 years of age. Overall macrolides are extensively used worldwide, and this has led to the emergence of macrolide-resistant M. pneumoniae, which may be associated with severe clinical features and more extrapulmonary complications. This review focuses on the characteristics of M. pneumoniae infections in children, and exemplifies that simple clinical decision rules may help identifying children at high risk for CAP due to M. pneumoniae. This may aid physicians in prescribing appropriate first-line antibiotics, since current diagnostic tests for M. pneumoniae infection are not reliably predictive.

Efficacy and safety of oral solithromycin versus oral moxifloxacin for treatment of community-acquired bacterial pneumonia: a global, double-blind, multicentre, randomised, active-controlled, non-inferiority trial (SOLITAIRE-ORAL)

BACKGROUND

Community-acquired bacterial pneumonia (CABP) is a leading cause of morbidity and mortality, and treatment recommendations, each with specific limitations, vary globally. We aimed to compare the efficacy and safety of solithromycin, a novel macrolide, with moxifloxacin for treatment of CABP.

METHODS

We did this global, double-blind, double-dummy, randomised, active-controlled, non-inferiority trial at 114 centres in North America, Latin America, Europe, and South Africa. Patients (aged ≥18 years) with clinically and radiographically confirmed pneumonia of Pneumonia Outcomes Research Team (PORT) risk class II, III, or IV were randomly assigned (1:1), via an internet-based central block randomisation procedure (block size of four), to receive either oral solithromycin (800 mg on day 1, 400 mg on days 2-5, placebo on days 6-7) or oral moxifloxacin (400 mg on days 1-7). Randomisation was stratified by geographical region, PORT risk class (II vs III or IV), and medical history of asthma or chronic obstructive pulmonary disease. The study sponsor, investigators, staff, and patients were masked to group allocation. The primary outcome was early clinical response, defined as an improvement in at least two of four symptoms (cough, chest pain, sputum production, dyspnoea) with no worsening in any symptom at 72 h after the first dose of study drug, with a 10% non-inferiority margin. The primary analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT-01756339.

FINDINGS

Between Jan 3, 2013, and Sept 24, 2014, we randomly assigned 860 patients to receive solithromycin (n=426) or moxifloxacin (n=434). Patients were followed up to days 28-35 after first dose. Solithromycin was non-inferior to moxifloxacin in achievement of early clinical response: 333 (78·2%) patients had an early clinical response in the solithromycin group versus 338 (77·9%) patients in the moxifloxacin group (difference 0·29, 95% CI -5·5 to 6·1). Both drugs had a similar safety profile. 43 (10%) of 155 treatment-emergent adverse events in the solithromycin group and 54 (13%) of 154 such events in the moxifloxacin group were deemed to be related to study drug. The most common adverse events, mostly of mild severity, were gastrointestinal disorders, including diarrhoea (18 [4%] patients in the solithromycin group vs 28 [6%] patients in the moxifloxacin group), nausea (15 [4%] vs 17 [4%] patients) and vomiting (ten [2%] patients in each group); and nervous system disorders, including headache (19 [4%] vs 11 [3%] patients) and dizziness (nine [2%] vs seven [2%] patients).

INTERPRETATION

Oral solithromycin was non-inferior to oral moxifloxacin for treatment of patients with CABP, showing the potential to restore macrolide monotherapy for this indication.

FUNDING

Cempra.

Functional mapping of community-acquired respiratory distress syndrome (CARDS) toxin of Mycoplasma pneumoniae defines regions with ADP-ribosyltransferase, vacuolating and receptor-binding activities

Community-acquired respiratory distress syndrome (CARDS) toxin from Mycoplasma pneumoniae is a 591-amino-acid virulence factor with ADP-ribosyltransferase (ADPRT) and vacuolating activities. It is expressed at low levels during in vitro growth and at high levels during colonization of the lung. Exposure of experimental animals to purified recombinant CARDS toxin alone is sufficient to recapitulate the cytopathology and inflammatory responses associated with M. pneumoniae infection in humans and animals. Here, by molecular modelling, serial truncations and site-directed mutagenesis, we show that the N-terminal region is essential for ADP-ribosylating activity. Also, by systematic truncation and limited proteolysis experiments we identified a portion of the C-terminal region that mediates toxin binding to mammalian cell surfaces and subsequent internalization. In addition, the C-terminal region alone induces vacuolization in a manner similar to full-length toxin. Together, these data suggest that CARDS toxin has a unique architecture with functionally separable N-terminal and C-terminal domains.

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.

Clinical outcomes and macrolide resistance in Mycoplasma pneumoniae infection in Scotland, UK

Mycoplasma pneumoniae has a cyclical, epidemic pattern of infection and the most recent epidemic occurred in Europe in 2011. Macrolides are recommended for the treatment of M. pneumoniae respiratory tract infection, but macrolide resistance has been reported at low levels in Europe. The aim of the study was to examine the clinical impact of the recent M. pneumoniae epidemic in a hospital setting in Scotland and to determine whether macrolide-resistant strains are present. Data were analysed retrospectively for 307 patients with M. pneumoniae respiratory infection diagnosed in 2010 and 2011 in Edinburgh, UK. Genotypic macrolide resistance testing was also carried out in 32 patients in whom resistance was considered most likely, based on their clinical picture. We found that 175 patients (59 %) were admitted to hospital, 20 (7 %) were admitted to critical care and 97 (38 %) required oxygen. All 48 adult patients (100 %) were admitted to hospital, compared with 127 children (51 %). Adults were also more likely to require oxygen [odds ratio (OR) 4.964, P<0.001, 95 % confidence interval (CI) 2.129-11.803] and to be admitted to critical care (OR 4.909, P = 0.001, 95 % CI 1.735-13.829), compared with children. Macrolide resistance conferred by the 23S rRNA gene mutation was found in samples from 6 out of 32 patients (19 %) in the subset tested. The results suggest that the recent M. pneumoniae epidemic was associated with a significant burden of hospital admission locally. The study also describes the first case series of macrolide-resistant M. pneumoniae in the UK, indicating that macrolide resistance surveillance is warranted in preparation for the next epidemic.

[Acute respiratory failure due to Mycoplasma pneumonia]

INTRODUCTION

Respiratory infections due to Mycoplasma pneumoniae are typically mild and subacute. We report the case of a 40-year-old man hospitalized for acute respiratory distress in the context of an acute infection with Mycoplasma pneumoniae. Radiological and pulmonary function test were consistent with an acute infectious bronchiolitis.

CASE REPORT

The patient presented with isolated respiratory failure with profound hypoxemia requiring oxygen delivered at high concentration by face mask. The CT appearance of the lesions corresponded to a spread of bilateral micro-connected pulmonary nodules (a "tree-in-bud" pattern) associated with obstructive ventilatory disorder. The only pathogen identified by PCR on BAL and serology was Mycoplasma pneumoniae. The evolution was favorable with antibiotic therapy combined with corticosteroids.

CONCLUSION

Mycoplasma pneumoniae may be responsible for severe respiratory illness in the form of bronchiolitis. In the setting of severe acute community pneumoniae antibiotic treatment which is also effective against Mycoplasma pneumonia should be considered. In this case, corticosteroids may be an effective adjunct by their action on the small airways.

Mycoplasma pneumoniae in children with acute and refractory asthma

BACKGROUND

The presence of Mycoplasma pneumoniae has been associated with worsening asthma in children. Sensitive assays have been developed to detect M pneumoniae-derived community-acquired respiratory distress syndrome (CARDS) toxin.

OBJECTIVES

To identify the frequency and persistence of M pneumoniae detection in respiratory secretions of children with and without asthma and to evaluate antibody responses to M pneumoniae and the impact of M pneumoniae on biological markers, asthma control, and quality of life.

METHODS

We enrolled 143 pediatric patients (53 patients with acute asthma, 26 patients with refractory asthma, and 64 healthy controls; age range, 5-17 years) during a 20-month period with 2 to 5 follow-up visits. We detected M pneumoniae using CARDS toxin antigen capture and polymerase chain reaction and P1 adhesin polymerase chain reaction. Immune responses to M pneumoniae were determined by IgG and IgM levels directed against CARDS toxin and P1 adhesin. pH was measured in exhaled breath condensates, and asthma control and quality of life were assessed using the Asthma Control Test and Pediatric Asthma Quality of Life Questionnaire.

RESULTS

M pneumoniae was detected in 64% of patients with acute asthma, 65% with refractory asthma, and 56% of healthy controls. Children with asthma had lower antibody levels to M pneumoniae compared with healthy controls. Exhaled breath condensate pHs and asthma control and quality of life scores were lower in M pneumoniae-positive patients with asthma.

CONCLUSION

The results suggest that M pneumoniae detection is common in children, M pneumoniae detection is associated with worsening asthma, and children with asthma may have poor humoral immune responses to M pneumoniae.

[The role of atypical microorganisms and viruses in severe acute community-acquired pneumonia]

Usually, intensivists do not focus on atypical bacteria and viruses in severe community-acquired pneumonia (CAP). Only Legionella pneumophila and influenza virus, following the recent H1N1 influenza pandemic, are routinely suggested as responsible agents. However, CAP due to atypical bacteria may represent up to 44% of all CAP. Viral CAP is considered less severe than the usual bacterial ones, although 25% of them warrant hospitalization and 15% result in severe sepsis. Even though L. pneumophila is the most frequently atypical pathogen involved in severe cases, Mycoplasma pneumoniae may be responsible for multiorgan failure. To date, tools including detection of Legionella antigen in urine and Mycoplasma using polymerase chain reaction (PCR) allow rapid and accurate diagnosis. The treatment is based on macrolides and fluoroquinolones that can be associated in severe Legionnaire diseases. The presence of virus in CAP, either alone or in association with bacteria, has been demonstrated using molecular biology tests. These techniques also allowed the identification of several new viruses in CAP. However, the exact role of these detected viruses in CAP as well as the efficiency of antiviral therapy still represent major unsolved concerns.

Mycoplasma pneumoniae large DNA repetitive elements RepMP1 show type specific organization among strains

Mycoplasma pneumoniae is the smallest self-replicating bacterium with a streamlined genome of 0.81 Mb. Complete genome analysis revealed the presence of multiple copies of four large repetitive elements (designated RepMP1, RepMP2/3, RepMP4 and RepMP5) that are implicated in creating sequence variations among individual strains. Recently, we described RepMP1-associated sequence variations between reference strain M129 and clinical isolate S1 that involved three RepMP1-genes (i.e. mpn130, mpn137 and mpn138). Using PCR and sequencing we analyze 28 additional M. pneumoniae strains and demonstrate the existence of S1-like sequence variants in nine strains and M129-like variants in the remaining nineteen strains. We propose a series of recombination steps that facilitates transition from M129- to S1-like sequence variants. Next we examined the remaining RepMP1-genes and observed no other rearrangements related to the repeat element. The only other detected difference was varying numbers of the 21-nucleotide tandem repeats within mpn127, mpn137, mpn501 and mpn524. Furthermore, typing of strains through analysis of large RepMPs localized within the adhesin P1 operon revealed that sequence divergence involving RepMP1-genes mpn130, mpn137 and mpn138 is strictly type-specific. Once more our analysis confirmed existence of two highly conserved groups of M. pneumoniae strains.