An Asian study on the prevalence of atypical respiratory pathogens in community-acquired pneumonia

The protective effect and immunomodulatory ability of orally administrated Lacticaseibacillus rhamnosus GG against Mycoplasma pneumoniae infection in BALB/c mice

Mycoplasma pneumoniae represents one of the significant etiologies of community-acquired pneumonia in pediatric patients. However, clinical treatment of M. pneumoniae infection in children has encountered challenges due to the escalating resistance to quinolones. Numerous studies have highlighted the potential of probiotic lactobacillus administration in boosting immune responses to bacterial and viral respiratory infections. In this study, the protective efficacy of pre-oral administration of Lacticaseibacillus rhamnosus GG (LGG), Limosilactobacillus reuteri F275, Lactiplantibacillus plantarum NCIMB 8826, L. plantarum S1 or L. plantarum S2 was evaluated in the BALB/c mice model; it was observed that among these five strains of lactobacillus, the supplementation of LGG exhibited the most significant protective effect against M. pneumoniae infection. Moreover, when administered orally, both live LGG and heat-inactivated LGG have demonstrated efficacy in reducing the burden of M. pneumoniae in the lungs and alleviating pulmonary inflammation. Oral supplementation with LGG resulted in the inhibition of neutrophil recruitment into the lungs and increased recruitment of alveolar macrophages in M. pneumoniae-infected mice. Additionally, LGG supplementation led to increased production of IL-10 and secretory IgA (sIgA), while suppressing the levels of IL-1β, IL-6, IL-17A, and TNF-α in the lungs of mice infected with M. pneumoniae. The data suggests that supplementation with LGG can modulate immune responses, decrease pathogen load, and alleviate inflammatory injury in the lungs of M. pneumoniae-infected mice.

Hydatid Cysts of the Psoas Muscle: Insights from the Past Five Years

Echinococcosis represents a major public health issue and continues to be endemic in various regions around the world. Hydatid cysts are commonly located in the liver (primary site), followed by the lungs (secondary site). However, they are also found in less typical organs such as the spleen, kidneys, peritoneum, retroperitoneum, pancreas, gallbladder, and various other organs, as well as in striate muscles. Hydatid cysts involving the psoas muscle are rare, and in the past five years, only a few articles have addressed this condition due to its low incidence. Symptoms can be quite vague, and serological testing might return negative, making imaging studies crucial for an accurate diagnosis. Treatment options involve surgery alongside antiparasitic agents. Despite having a low mortality rate, the recurrence of hydatid disease remains high. This paper aims to provide new clinical data through our case presentation, while also offering a review of the cases of hydatid cysts involving the psoas muscle that have been published over the past five years.

Identification of Mycoplasma pneumoniae-associated pneumonia cases among hospitalized patients using CLART® microarray technology

Objectives

Community-acquired pneumonia (CAP) is a global health condition that affects populations from all age groups. The laboratory identification of Mycoplasma pneumoniae as a causative agent of CAP is challenging because of its atypical and fastidious nature. Therefore, this study assessed the diagnostic potential of PneumoCLART bacteria® in identifying M. pneumoniae as a causative agent of pneumonia in hospitalized adults.

Methods

This prospective study used a cross-sectional approach to assess the diagnostic potential of PneumoCLART bacteria® for detecting M. pneumoniae in sputum samples procured from 27 patients with pneumonia who required hospitalization.

Results

The PneumoCLART bacteria® results illustrated that 7 of 27 patients with pneumonia were positive for M. pneumoniae (26%). However, the quality of sputum varied among the M. pneumoniae-positive and M. pneumoniae-negative samples. Fifty percent of the specimens obtained from patients positive for M. pneumoniae were saliva-contaminated and unsuitable for analysis.

Conclusions

Because the leukocyte count was low and sputum specimens were saliva-contaminated, these findings require further validation to prove the utility of CLART® microarray technology for the identification of M. pneumoniae in pneumonia-positive patients. Conclusively, this prospective study included a small number of clinical samples, which likely affected its outcomes.

Pinocembrin Relieves Mycoplasma pneumoniae Infection‑Induced Pneumonia in Mice Through the Inhibition of Oxidative Stress and Inflammatory Response

Pneumonia is a serious infectious disease with increased morbidity and mortality worldwide. The M. pneumoniae is a major airway pathogen that mainly affects respiratory tract and ultimately leads to the development of pneumonia. The current exploration was aimed to uncover the beneficial properties of pinocembrin against the M. pneumoniae-triggered pneumonia in mice via its anti-inflammatory property. The pneumonia was stimulated to the BALB/c mice via infecting them with M. pneumoniae (100 µl) for 2 days through nasal drops and concomitantly treated with pinocembrin (10 mg/kg) for 3 days. The azithromycin (100 mg/kg) was used as a standard drug. Then the lung weight, nitric oxide, and myeloperoxidase (MPO) activity was assessed. The content of MDA, GSH, and SOD activity was scrutinized using kits. The total cells and DNA amount present in the bronchoalveolar lavage fluid (BALF) was assessed by standard methods. The IL-1, IL-6, IL-8, TNF-α, and TGF contents in the BALF samples and NF-κB level in the lung tissues were assessed using kits. The lung histopathology was assessed microscopically to detect the histological alterations. The 10 mg/kg of pinocembrin treatment substantially decreased the lung weight, nitric oxide (NO) level, and MPO activity. The MDA level was decreased, and GSH content and SOD activity were improved by the pinocembrin treatment. The pinocembrin administered pneumonia animals also demonstrated the decreased total cells, DNA amount, IL-1, IL-6, IL-8, TNF-α, and TGF in the BALF and NF-κB level. The findings of histological studies also witnessed the beneficial role of pinocembrin against M. pneumoniae-infected pneumonia. In conclusion, our findings confirmed that the pinocembrin effectively ameliorated the M. pneumoniae-provoked inflammation and oxidative stress in the pneumonia mice model. Hence, it could be a hopeful therapeutic agent to treat the pneumonia in the future.

Multi-Modal Data Analysis for Pneumonia Status Prediction Using Deep Learning (MDA-PSP)

Evaluating several vital signs and chest X-ray (CXR) reports regularly to determine the recovery of the pneumonia patients at general wards is a challenge for doctors. A recent study shows the identification of pneumonia by the history of symptoms and signs including vital signs, CXR, and other clinical parameters, but they lack predicting the recovery status after starting treatment. The goal of this paper is to provide a pneumonia status prediction system for the early affected patient’s discharge from the hospital within 7 days or late discharge more than 7 days. This paper aims to design a multimodal data analysis for pneumonia status prediction using deep learning classification (MDA-PSP). We have developed a system that takes an input of vital signs and CXR images of the affected patient with pneumonia from admission day 1 to day 3. The deep learning then classifies the health status improvement or deterioration for predicting the possible discharge state. Therefore, the scope is to provide a highly accurate prediction of the pneumonia recovery on the 7th day after 3-day treatment by the SHAP (SHapley Additive exPlanation), imputation, adaptive imputation-based preprocessing of the vital signs, and CXR image feature extraction using deep learning based on dense layers-batch normalization (BN) with class weights for the first 7 days’ general ward patient in MDA-PSP. A total of 3972 patients with pneumonia were enrolled by de-identification with an adult age of 71 mean ± 17 sd and 64% of them were male. After analyzing the data behavior, appropriate improvement measures are taken by data preprocessing and feature vectorization algorithm. The deep learning method of Dense-BN with SHAP features has an accuracy of 0.77 for vital signs, 0.92 for CXR, and 0.75 for the combined model with class weights. The MDA-PSP hybrid method-based experiments are proven to demonstrate higher prediction accuracy of 0.75 for pneumonia patient status. Henceforth, the hybrid methods of machine and deep learning for pneumonia patient discharge are concluded to be a better approach.

Toll-Like Receptor 2 Modulates Pulmonary Inflammation and TNF-α Release Mediated by Mycoplasma pneumoniae

Objectives

To investigate the roles that Toll-like receptors (TLRs) play in lung inflammation mediated by Mycoplasma pneumoniae (MP).

Methods

The changes in TLRs and tumor necrosis factor alpha (TNF-α) in peripheral blood of children with M. pneumoniae pneumonia (MPP) were monitored, and the interactions of signaling molecules regulating TNF-α release in A549 cells and neutrophils after M. pneumoniae stimulation were investigated. In TLR2 knockout (TLR2-/-) mice, the levels of TNF-α in bronchial alveolar lavage fluid (BALF) and peripheral blood after mycoplasma infection and the pathological changes in the lung tissue of mice were detected.

Results

TNF-α levels in peripheral blood of children with MPP were higher than those in non-infected children, and children with refractory MPP had the highest levels of TNF-α and TLR2. TNF-α secretion and TLR2, myeloid differentiation primary response 88 (MyD88) and phospho-p65(p-p65) levels were increased in stimulated cells. TNF-α secretion was suppressed upon siRNA-mediated TLR2 silencing. Pharmacological inhibition of nuclear factor-kappa B (NF-κB) and MyD88 effectively reduced TNF-α expression. Compared with wild-type mice, the TNF-α in serum and BALF decreased, and lung pro-inflammatory response was partially suppressed in TLR2-/- mice.

Conclusion

We concluded that TLR2 regulates M. pneumoniae-mediated lung inflammation and TNF-α release through the TLR2-MyD88-NF-κB signaling pathway.

The COVID-19 Pandemic and the Incidence of the Non-COVID-19 Pneumonia in Adults

Introduction: The coronavirus disease 2019 (COVID-19) lockdown strategies were associated with a significant decrease in the common respiratory viral diseases and decreased the need for hospitalization among children in the COVID-19 outbreak. However, the trend of non-COVID-19 pneumonia in adult people remains uncertain. Our aim is to assess the impact of the COVID-19 pandemic on the incidence of the non-COVID-19 pneumonia in adult people and understand whether the substantial decrease in pneumonia cases is the same as the decline in the incidence of respiratory viral disease activity.

Methods: We conducted a retrospective analysis of adult patients presenting with pneumonia from January 2019 to December 2020. Details on all the demographics of the patient of pneumonia, hospital course details, prior admission history within 3 months, respiratory culture, and antibiotics sensitivity test were also obtained.

Results: The number of adult patients with community-acquired pneumonia in 2020 was lower than that in 2019, which decreased by 74 patients in 2020. The decreasing number of patients with community-acquired pneumonia between 2019 and 2020 was from −13.9% in January to March 2020 to −39.7% in October to December 2020. The decreasing number of patients with community-acquired pneumonia between 2019 and 2020 was from −14.8% in the youngest cohort to −28.7% in those aged ≥85 years. The number of reduced patients with community-acquired pneumonia is greater in late seasons and older age, respectively. The number of adult patients with hospital-acquired pneumonia in 2020 was lower than that in 2019, which decreased by 23 patients in 2020. The decreasing number of patients with hospital-acquired pneumonia between 2019 and 2020 was from −20.0% in January to March 2020 to −52.4% in October to December 2020. The decreasing number of patients with hospital-acquired pneumonia between 2019 and 2020 was from 0% in the youngest cohort to −45.6% in those aged ≥ 85 years. The number of reduced patients with hospital-acquired pneumonia is greater in late seasons and older age, respectively.

Conclusion: Interventions applied to control the COVID-19 pandemic were effective not only in substantial changes in the seasonal influenza activity, but also in decreasing adult pneumonia cases.

Approach to Identifying Causative Pathogens of Community-Acquired Pneumonia in Children Using Culture, Molecular, and Serology Tests

Determining the causative pathogen(s) of community-acquired pneumonia (CAP) in children remains a challenge despite advances in diagnostic methods. Currently available guidelines generally recommend empiric antimicrobial therapy when the specific etiology is unknown. However, shifts in epidemiology, emergence of new pathogens, and increasing antimicrobial resistance underscore the importance of identifying causative pathogen(s). Although viral CAP among children is increasingly recognized, distinguishing viral from bacterial etiologies remains difficult. Obtaining high quality samples from infected lung tissue is typically the limiting factor. Additionally, interpretation of results from routinely collected specimens (blood, sputum, and nasopharyngeal swabs) is complicated by bacterial colonization and prolonged shedding of incidental respiratory viruses. Using current literature on assessment of CAP causes in children, we developed an approach for identifying the most likely causative pathogen(s) using blood and sputum culture, polymerase chain reaction (PCR), and paired serology. Our proposed rules do not rely on carriage prevalence data from controls. We herein share our perspective in order to help clinicians and researchers classify and manage childhood pneumonia.

Evaluation on blood coagulation and C-reactive protein level among children with mycoplasma pneumoniae pneumonia by different chest imaging findings

Mycoplasma pneumoniae infection may induce a systemic hypercoagulable abnormality, like organ embolism and infarction. Indexes of blood coagulation and C-reactive protein (CRP) have been reported different between healthy people and mycoplasma pneumoniae pneumonia (MPP) patients, but this difference in MPP patients with different chest imaging findings has rarely been reported.We performed a retrospective study of 101 children with MPP and 119 controls, combined with radiological examination and blood tests, to compare the blood coagulation and CRP level among MPP children with different chest imaging findings.For the MPP children with different chest imaging findings, there were significant differences in CRP, fibrinogen (FIB) and D-dimer (D-D) levels among subgroups (P = .004, P = .008 and P < .001 respectively). The CRP level in group of interstitial pneumonia was significantly higher than that in groups of bronchopneumonia and hilar shadow thickening (P = .003 and P = .001 respectively). And the FIB and D-D values in group of lung consolidation were significantly higher than that in the other 3 groups (all P < .05). When compared with controls, the white blood cell, CRP, FIB, and D-D levels in MPP children were significantly higher, and the activated partial thromboplastin time and thrombin time levels were significantly lower (all P < .05).Our results showed that CRP level changed most significantly in group of interstitial pneumonia, whereas FIB, D-D levels changed most significantly in the lung consolidation group.

Antibodies against atypical pathogens and respiratory viruses detected by Pneumoslide IgM test in adults with community-acquired pneumonia in Guangzhou City

Background

To detect the serum antibodies against respiratory viruses and atypical pathogens in adults with community‐acquired pneumonia (CAP) in Guangzhou City (Guangdong province, China).

Methods

A retrospective study was carried out with samples from 685 adults who were admitted with CAP and 108 non‐CAP control patients. Atypical pathogens and respiratory viruses in serum were detected using the Pneumoslide IgM test from Vircell, Spain. All patients were divided into 6 groups according to age: 18‐24, 25‐44, 45‐59, 60‐74, 75‐89, and >90.

Results

The total positive rate of CAP was 35.4%, which was highest in the 18‐24 age group (P < .05). The highest positive rate, 17.11%, was observed for Mycoplasma pneumoniae (MP). The mean age of MP‐infected patients was higher than that of the controls (P < .05). The positive rates for influenza B (INFB), Legionella pneumophila (LP1), Coxiella burnetii (COX), influenza A (INFA), parainfluenza virus (PIV), respiratory syncytial virus (RSV), Chlamydophila pneumoniae (CP), and adenovirus (ADV) were 5.56%, 3.07%, 2.63%, 2.34%, 1.90%, 1.61, 0.88%, and 0.29%, respectively. There were 4.37% of patients with CAP having multiple infections. The main symptoms observed in the 685 CAP patients were cough and sputum production, in 78.4% and 67.4%. Fever was followed by 54% of CAP patients. Dyspnea (39.1%), anorexia (36.8%), increased thirst (26.7%), chills (18.7), headache (14.6%), and nausea (13.1%) were also frequently observed in the CAP patients.

Conclusions

MP infection was the most common in adult CAP patients in Guangzhou City with the highest positive rate in the 18‐24 age groups.

Bacterial pneumonia and its associated factors in children from a developing country: A prospective cohort study

Introduction

Pneumonia in children is a common disease yet determining its aetiology remains elusive.

Objectives

To determine the a) aetiology, b) factors associated with bacterial pneumonia and c) association between co-infections (bacteria + virus) and severity of disease, in children admitted with severe pneumonia.

Methods

A prospective cohort study involving children aged 1-month to 5-years admitted with very severe pneumonia, as per the WHO definition, over 2 years. Induced sputum and blood obtained within 24 hrs of admission were examined via PCR, immunofluorescence and culture to detect 17 bacteria/viruses. A designated radiologist read the chest radiographs.

Results

Three hundred patients with a mean (SD) age of 14 (±15) months old were recruited. Significant pathogens were detected in 62% of patients (n = 186). Viruses alone were detected in 23.7% (n = 71) with rhinovirus (31%), human metapneumovirus (HMP) [22.5%] and respiratory syncytial virus (RSV) [16.9%] being the commonest. Bacteria alone was detected in 25% (n = 75) with Haemophilus influenzae (29.3%), Staphylococcus aureus (24%) and Streptococcus pneumoniae (22.7%) being the commonest. Co-infections were seen in 13.3% (n = 40) of patients. Male gender (AdjOR 1.84 [95% CI 1.10, 3.05]) and presence of crepitations (AdjOR 2.27 [95% CI 1.12, 4.60]) were associated with bacterial infection. C-reactive protein (CRP) [p = 0.007]) was significantly higher in patients with co-infections but duration of hospitalization (p = 0.77) and requirement for supplemental respiratory support (p = 0.26) were not associated with co-infection.

Conclusions

Bacteria remain an important cause of very severe pneumonia in developing countries with one in four children admitted isolating bacteria alone. Male gender and presence of crepitations were significantly associated with bacterial aetiology. Co-infection was associated with a higher CRP but no other parameters of severe clinical illness.

Epidemiology of Mycoplasma pneumoniae prevalence in Iranian patients: a systematic review and meta-analysis

Introduction. Mycoplasma pneumoniae is regarded as the important infectious agent of acute respiratory infections (ARIs) in the world. However, there is little knowledge about the prevalence of M. pneumoniae in Iran. Therefore, the aim of this study was to investigate the prevalence of M. pneumoniae in Iran through a meta-analysis of included studies.Methods. A systematic search was done by using electronic databases from papers that were published by Iranian authors to the end of February 2019. Then, 12 publications, which met our inclusion criteria, were enrolled for data extraction and analysis by using the 'metaprop program' in stata version 14.0.Results. The pooled prevalence of M. pneumoniae was 9 % (95 % confidence intervals: 5-16 %) ranging from 1 to 26 %. There was a significant heterogeneity among the 12 studies (X²=128.29; P<0.001; I ²=91.43 %). The funnel plot for publication bias showed no evidence of asymmetry.Conclusions. The frequency of M. pneumoniae in Iran is comparable with other parts of the world. Although the overall prevalence of M. pneumoniae was low, awareness about the distribution of these agent is very important because of higher infection rates in susceptible groups. In addition, these results showed the rates of M. pneumoniae had variation based on location, type of infection and sample, gender and detection rate and there was evidence of publication bias.

Disease severity and clinical outcomes of community-acquired pneumonia caused by non-influenza respiratory viruses in adults: a multicentre prospective registry study from the CAP-China Network

Although broad knowledge of influenza viral pneumonia has been established, the significance of non-influenza respiratory viruses in community-acquired pneumonia (CAP) and their impact on clinical outcomes remains unclear, especially in the non-immunocompromised adult population.Hospitalised immunocompetent patients with CAP were prospectively recruited from 34 hospitals in mainland China. Respiratory viruses were detected by molecular methods. Comparisons were conducted between influenza and non-influenza viral infection groups.In total, 915 out of 2336 adult patients with viral infection were enrolled in the analysis, with influenza virus (28.4%) the most frequently detected virus, followed by respiratory syncytial virus (3.6%), adenovirus (3.3%), human coronavirus (3.0%), parainfluenza virus (2.2%), human rhinovirus (1.8%) and human metapneumovirus (1.5%). Non-influenza viral infections accounted for 27.4% of viral pneumonia. Consolidation was more frequently observed in patients with adenovirus infection. The occurrence of complications such as sepsis (40.1% versus 39.6%; p=0.890) and hypoxaemia (40.1% versus 37.2%; p=0.449) during hospitalisation in the influenza viral infection group did not differ from that of the non-influenza viral infection group. Compared with influenza virus infection, the multivariable adjusted odds ratios of CURB-65 (confusion, urea >7 mmol·L^-1, respiratory rate ≥30 breaths·min^-1, blood pressure <90 mmHg (systolic) or ≤60 mmHg (diastolic), age ≥65 years) ≥3, arterial oxygen tension/inspiratory oxygen fraction <200 mmHg, and occurrence of sepsis and hypoxaemia for non-influenza respiratory virus infection were 0.87 (95% CI 0.26-2.84), 0.72 (95% CI 0.26-1.98), 1.00 (95% CI 0.63-1.58) and 1.05 (95% CI 0.66-1.65), respectively. The hazard ratio of 90-day mortality was 0.51 (95% CI 0.13-1.91).The high incidence of complications in non-influenza viral pneumonia and similar impact of non-influenza respiratory viruses relative to influenza virus on disease severity and outcomes suggest more attention should be given to CAP caused by non-influenza respiratory viruses.

Evaluation of the prevalence of Legionella pneumophila in Iranian clinical samples: A systematic review and meta-analysis

BACKGROUND

Legionella pneumophila is the main cause for community-acquired pneumonia especially in hospital environments. In this systematic review and meta-analysis, we evaluated the prevalence of L. pneumophila in clinical samples obtained from Iranian patients.

METHODS

The studies reporting L. pneumophila prevalence in Iranian clinical samples that were published between January 2000 and July 2016 were recruited. Comprehensive Meta-Analysis Software (version 3.3.070) was used for quantitative data analysis. Because of high heterogeneity between the studies according to the Cochrane Q and I2 statistics, a random-effects model was used for meta-analysis.

RESULTS

Sixteen studies encompassing 1956 subjects were included in the meta-analysis. The overall prevalence of L. pneumophila was 9.6% in clinical samples obtained from the Iranian patients. The age spectrum ranged from 6 months to 80 years old. Dyspnea and cough comprised the most common clinical manifestations. In the subgroup analysis, the prevalence of L. pneumophila was higher in studies with sample size ≤100 (12.9%) in comparison with studies with sample size >100 (8.4%). In addition, the prevalence of L. pneumophila was higher in the years 2009-2016 (9.2%) compared with 2000-2008 (0.7%).

CONCLUSION

L. pneumophila is a major cause of community- and hospital-acquired pneumonia. It is of pivotal importance to implement sensitive and reliable molecular and culture-based techniques to detect and control this infection in healthcare environments.

Recommendations and guidelines for the treatment of pneumonia in Taiwan

Pneumonia is a leading cause of death worldwide, ranking third both globally and in Taiwan. This guideline was prepared by the 2017 Guidelines Recommendations for Evidence-based Antimicrobial agents use in Taiwan (GREAT) working group, formed under the auspices of the Infectious Diseases Society of Taiwan (IDST). A consensus meeting was held jointly by the IDST, Taiwan Society of Pulmonary and Critical Care Medicine (TSPCCM), the Medical Foundation in Memory of Dr. Deh-Lin Cheng, the Foundation of Professor Wei-Chuan Hsieh for Infectious Diseases Research and Education and CY Lee's Research Foundation for Pediatric Infectious Diseases and Vaccines. The final guideline was endorsed by the IDST and TSPCCM. The major differences between this guideline and the 2007 version include the following: the use of GRADE methodology for the evaluation of available evidence whenever applicable, the specific inclusion of healthcare-associated pneumonia as a category due to the unique medical system in Taiwan and inclusion of recommendations for treatment of pediatric pneumonia. This guideline includes the epidemiology and recommendations of antimicrobial treatment of community-acquired pneumonia, hospital-acquired pneumonia, ventilator-associated pneumonia, healthcare-associated pneumonia in adults and pediatric pneumonia.

High expression of HMGB1 in children with refractory Mycoplasma pneumoniae pneumonia

Background

Increasing numbers of refractory or severe, even fatal, cases of Mycoplasma pneumoniae infections have been reported in recent years. Excessive inflammatory responses play a vital role in the pathogenesis of refractory M. pneumoniae pneumonia (RMPP). HMGB1 is an actively secreted cytokine produced by macrophages and other inflammatory cells that participates in various infectious diseases. The present study aimed to explore the role and clinical significance of HMGB1 in children with RMPP and the potential mechanism of HMGB1 expression.

Methods

Four hundred and fifty-two children diagnosed with M. pneumoniae pneumonia, including 108 children with RMPP, were enrolled from January 2013 to December 2015 at the Children’s Hospital of Soochow University. HMGB1, TNF-α, and IL-6 in peripheral blood from RMPP and non-RMPP (NRMPP) cases were detected by real-time PCR and ELISA. Lipid-associated membrane proteins (LAMPs) were extracted from live M. pneumoniae and prepared at different concentrations for stimulation of THP-1 cells. After coculture with LAMPs, HMGB1, TNF-α, IL-6, RAGE, TLR2, and TLR4 in THP-1 cells were detected by real-time PCR.

Results

Occurrences of cough, fever, and abnormal lung signs were more frequent in RMPP cases compared with NRMPP cases (all p < 0.05). Children with RMPP had longer hospital stays than children with NRMPP (p < 0.05). Different distributions of lymphocytes were noted between RMPP and NRMPP cases. HMGB1, TNF-α, and IL-6 levels were significantly higher in RMPP cases compared with NRMPP cases (all p < 0.05). HMGB1 had good diagnostic ability to differentiate RMPP with AUC of 0.876, sensitivity of 0.833, and specificity of 0.824 compared with TNF-α and IL-6. HMGB1 expression in THP-1 cells was increased by stimulation with 10 μg/ml LAMPs. TLR2 expression was increased after stimulation with 6 μg/ml LAMPs. HMGB1 level was positively associated with TNF-α, IL-6, and TLR2 levels.

Conclusions

HMGB1 is a good diagnostic biomarker for differentiating RMPP and NRMPP. LAMPs from M. pneumoniae may induce HMGB1 expression in immune cells through the TLR2 pathway. Further in vitro and in vivo studies are needed for the development of a new treatment strategy to inhibit the HMGB1 pathway, thereby preventing the inflammation in RMPP.

Severe atypical pneumonia in critically ill patients: a retrospective multicenter study

BACKGROUND

Chlamydophila pneumoniae (CP) and Mycoplasma pneumoniae (MP) patients could require intensive care unit (ICU) admission for acute respiratory failure.

METHODS

Adults admitted between 2000 and 2015 to 20 French ICUs with proven atypical pneumonia were retrospectively described. Patients with MP were compared to Streptococcus pneumoniae (SP) pneumonia patients admitted to ICUs.

RESULTS

A total of 104 patients were included, 71 men and 33 women, with a median age of 56 [44-67] years. MP was the causative agent for 76 (73%) patients and CP for 28 (27%) patients. Co-infection was documented for 18 patients (viruses for 8 [47%] patients). Median number of involved quadrants on chest X-ray was 2 [1-4], with alveolar opacities (n = 61, 75%), interstitial opacities (n = 32, 40%). Extra-pulmonary manifestations were present in 34 (33%) patients. Mechanical ventilation was required for 75 (72%) patients and vasopressors for 41 (39%) patients. ICU length of stay was 16.5 [9.5-30.5] days, and 11 (11%) patients died in the ICU. Compared with SP patients, MP patients had more extensive interstitial pneumonia, fewer pleural effusion, and a lower mortality rate [6 (8%) vs. 17 (22%), p = 0.013]. According MCA analysis, some characteristics at admission could discriminate MP and SP. MP was more often associated with hemolytic anemia, abdominal manifestations, and extensive chest radiograph abnormalities. SP-P was associated with shock, confusion, focal crackles, and focal consolidation.

CONCLUSION

In this descriptive study of atypical bacterial pneumonia requiring ICU admission, mortality was 11%. The comparison with SP pneumonia identified clinical, laboratory, and radiographic features that may suggest MP or CP pneumonia.

Epidemiology, microbiology, and treatment patterns of pediatric patients hospitalized with pneumonia at two hospitals in China: a patient chart review study

Background

The etiology, epidemiology, treatment patterns, and clinical outcomes of neonatal and pediatric pneumonia patients in China are not well reported. This retrospective chart review study aimed to describe such information among neonatal (0 to 27 days) and pediatric (28 days to <18 years) pneumonia patients in two regions of China.

Methods

Electronic medical records of pneumonia hospitalizations (aged <18 years) admitted between 2008 and 2013 from four hospitals under Guangdong Provincial Hospital of Chinese Medicine (Southern China) and between 2010 and 2014 at Peking University People's Hospital (Beijing, Northern China) were reviewed.

Results

The average age of neonatal hospitalizations in Beijing (n=92) was 3.5 days. The mean length of hospital stay was 11.2 days, and no deaths occurred. Staphylococcus epidermidis was the most common bacteria found in Beijing patients, whereas Mycoplasma pneumoniae was the most common bacteria found in Guangdong patients. The average age of pediatric hospitalizations was 3.3 (±3.1) and 6.5 (±5.6) years in Guangdong (n=3,046) and Beijing (n=222), respectively. The mean length of hospital stay was 17.4 and 5.8 days, and overall mortality rates were 0.2% and 0.5%.

Conclusion

The findings revealed a low level of bacterial isolation and hence microbiological diagnoses. There was a low level of in-hospital mortality due to pneumonia, and the majority of hospitalizations were discharged from hospital, suggesting that current practice was generally effective. Neonatal hospitalizations were greater than pediatric hospitalizations in Beijing along with disparity in bacterial profile when compared with Guangdong, intending a need to improve neonatal pneumonia prophylaxis and selection of appropriate treatment.

Evaluation of variation in coagulation among children with Mycoplasma pneumoniae pneumonia: a case-control study

Objective Acute organ embolism in children with Mycoplasma pneumoniae pneumonia (MPP) has been reported, but changes in coagulation are unclear. This study aimed to investigate changes in coagulation in children with MPP. Methods A total of 185 children with MMP (cases) and 117 healthy children (controls) were recruited. We measured prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and plasma fibrinogen (FIB) and D-dimer levels. Results Plasma FIB (3.39 ± 0.96 g/L vs 2.93 ± 0.6 6g/L, t = 4.50) and D-dimer (326.45 ± 95.62mg/L vs 263.93 ± 103.32mg/L, t=5.36) in MPP children were higher than controls and PT (9.54 ± 4.97S vs 11.48 ± 5.96S, t=3.05) and APTT (31.41 ± 12.01S vs 38.38 ± 11.72S, t=4.95) were shorter than controls. FIB, D-dimer, PT, and APTT were not different between the high IgM-titre and low-titre groups. The areas under the receiver operating characteristic curves in cases and controls for plasma FIB and D-dimer levels were 0.654 (95% confidence interval [CI], 0.593-0.716, P = 0.031) and 0.682 (95% CI, 0.619-0.744, P = 0.032), respectively. Conclusions Children with MPP have a higher risk of blood coagulation and thrombosis. Controlling these problems should be considered as soon as possible.

Molecular Characterization of Mycoplasma pneumoniae Infections in Two Rural Populations of Thailand from 2009 to 2012

Studies on Mycoplasma pneumoniae in Thailand have focused on urban centers and have not included molecular characterization. In an attempt to provide a more comprehensive understanding of this organism, we conducted a systematic random sampling to identify 3,000 nasopharyngeal swab specimens collected from January 2009 through July 2012 during population-based surveillance for influenza-like illness in two rural provinces. M. pneumoniae was detected by real-time PCR in 175 (5.8%) specimens. Genotyping was performed using the major adhesion protein (P1) and multilocus variable-number tandem-repeat analysis (MLVA). Of the 157 specimens typed, 97 were P1 type 1 and 60 were P1 type 2. Six different MLVA profiles were identified in 149 specimens, with 4/5/7/2 (40%) and 3/5/6/2 (26%) predominating. There was no discrete seasonality to M. pneumoniae infections. Examination of the 23S rRNA sequence for known polymorphisms conferring macrolide resistance revealed that all 141 tested to possess the genotype associated with macrolide susceptibility.

Community-Acquired Pneumonia in the Asia-Pacific Region

Community-acquired pneumonia (CAP) is an important cause of mortality and morbidity worldwide. Aging population, dense urbanization, and poor access to health care make the Asia-Pacific region vulnerable to CAP. The high incidence of CAP poses a significant health and economic burden in this region. Common etiologic agents in other global regions including Streptococcus pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae, Chlamydophila pneumoniae, Staphylococcus aureus, and respiratory viruses are also the most prevalent pathogens in the Asia-Pacific region. But the higher incidence of Klebsiella pneumoniae and the presence of Burkholderia pseudomallei are unique to the region. The high prevalence of antimicrobial resistance in S. pneumoniae and M. pneumoniae has been raising the need for more prudent use of antibiotics. Emergence and spread of community-acquired methicillin-resistant S. aureus deserve attention, while the risk has not reached significant level yet in cases of CAP. Given a clinical and socioeconomic importance of CAP, further effort to better understand the epidemiology and impact of CAP is warranted in the Asia-Pacific region.

Pathogenesis of Mycoplasma pneumoniae: An update

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

Study of Two Separate Types of Macrolide-Resistant Mycoplasma pneumoniae Outbreaks

To study the complete natural process of a Mycoplasma pneumoniae outbreak in a semiclosed room such as a primary school room, we investigated two separate M. pneumoniae outbreaks involving 81 students in total in two primary schools in Hangzhou, China. M. pneumoniae isolates from pharyngeal swabs were detected by fluorescence quantitative real-time PCR (RT-PCR) and culture. The class in school M had 39 students, with 12 (30.8%) with positive M. pneumoniae detection results. The class from school J had 42 students, with 13 (31.0%) positive. The strains from two classes were confirmed to represent two clones (3/4/5/7/2 and 5/4/5/7/2) and to be macrolide resistant (A2063G) according to P1 and multilocus variable-number tandem-repeat analysis (MLVA) genotyping, determination of MIC of antibiotics, and sequencing. Students with M. pneumoniae isolates detected were divided into three groups: those carrying the isolates, those with upper respiratory tract infection (URI), and those with pneumonia. Longitudinal sampling performed using pharyngeal swabs showed that the persistence of M. pneumoniae was longest in the group of students with pneumonia. M. pneumoniae causes pneumonia outbreaks in schools, and the incidence of pneumonia has a higher rate than that of URI. The persistence of M. pneumoniae, with a median duration of 79.50 days in the group of students with pneumonia, differs from that of the infection state.

Atypical Pneumonia - Screening in a Tertiary Care Centre

INTRODUCTION

Pneumonia is one of the leading infectious causes of mortality and morbidity worldwide. Atypical respiratory pathogens account for 30 - 40% of these infections. The three most important atypical pathogens are Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila.

AIM

To screen for atypical pathogens as cause for community acquired pneumonia.

MATERIALS AND METHODS

A cross-sectional study was done with 107 patients who had clinical suspicion of atypical pneumonia. The presence of atypical pathogens Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila were screened from the patient's sample. Respiratory samples in the form of sputum, Broncheoalveolar lavage and Non- Broncheoalveolar lavage were used for cultivation of Mycoplasma pneumoniae and Legionella pneumophila. Urine specimen was used for the detection of Legionella antigen. Serum samples were used for the detection of Mycoplasma pneumoniae IgM and Chlamydophila pneumoniae IgM antibodies.

RESULTS

Among the 107 samples screened, 13(12.1%) were positive for antibodies against atypical pathogens. Out of which 7(6.5%) had IgM antibodies against Mycoplasma pneumoniae and the rest 6(5.6%) had Chlamydophila pneumoniae IgM antibodies. All the samples were culture negative for Mycoplasma pneumoniae and Legionella pneumophila. Urinary antigen detection for Legionella pneumophila was also negative in patients.

CONCLUSION

Atypical pathogens should also be considered routinely as a cause of lower respiratory tract infections, especially Chlamydia pneumoniae and Mycoplasma pneumoniae in our country. Serological diagnosis by ELISA can be adopted for determining the infections by atypical pathogens as cultivation is difficult and also requires special media and prolonged incubation. This may not be feasible for many laboratories. Early diagnosis and treatment will reduce the complications.

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

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

Viral and atypical bacterial aetiologies of infection in hospitalised patients admitted with clinical suspicion of influenza in Thailand, Vietnam and Indonesia

Background

Influenza constitutes a leading cause of morbidity and mortality worldwide. There is limited information about the aetiology of infection presenting clinically as influenza in hospitalised adults and children in South-East Asia. Such data are important for future management of respiratory infections.

Objectives

To describe the aetiology of infection presenting clinically as influenza in those hospitalised in South-East Asia.

Methods

Respiratory specimens archived from July 2008 to June 2009 from patients hospitalised with suspected influenza from Indonesia, Thailand and Vietnam were tested for respiratory viruses and atypical bacteria by polymerase chain reaction.

Results

A total of 1222 patients’ samples were tested. Of 1222, 776 patients (63·5%) were under the age of 5. Viruses detected included rhinoviruses in 229 of 1222 patients (18·7%), bocaviruses in 200 (16·4%), respiratory syncytial viruses in 144 (11·8%), parainfluenza viruses in 140 (11·5%; PIV1: 32; PIV2: 12; PIV3: 71; PIV4: 25), adenovirus in 102 (8·4%), influenza viruses in 93 (7·6%; influenza A: 77; influenza B: 16) and coronaviruses in 23 (1·8%; OC43: 14; E229: 9). Bacterial pathogens were Mycoplasma pneumoniae (n = 33, 2·7%), Chlamydophila psittaci (n = 2), C. pneumoniae (n = 1), Bordetella pertussis (n = 1) and Legionella pneumophila (n = 2). Overall, in-hospital case fatality rate was 29 of 1222 (2·4%).

Conclusion

Respiratory viruses were the most commonly detected pathogens in patients hospitalised with a clinical suspicion of influenza. Rhinovirus was the most frequently detected virus, and M. pneumoniae, the most common atypical bacterium. The low number of detected influenza viruses demonstrates a low benefit for empirical oseltamivir therapy, unless during an influenza outbreak.

Current and emerging Legionella diagnostics for laboratory and outbreak investigations

Legionnaires' disease (LD) is an often severe and potentially fatal form of bacterial pneumonia caused by an extensive list of Legionella species. These ubiquitous freshwater and soil inhabitants cause human respiratory disease when amplified in man-made water or cooling systems and their aerosols expose a susceptible population. Treatment of sporadic cases and rapid control of LD outbreaks benefit from swift diagnosis in concert with discriminatory bacterial typing for immediate epidemiological responses. Traditional culture and serology were instrumental in describing disease incidence early in its history; currently, diagnosis of LD relies almost solely on the urinary antigen test, which captures only the dominant species and serogroup, Legionella pneumophila serogroup 1 (Lp1). This has created a diagnostic "blind spot" for LD caused by non-Lp1 strains. This review focuses on historic, current, and emerging technologies that hold promise for increasing LD diagnostic efficiency and detection rates as part of a coherent testing regimen. The importance of cooperation between epidemiologists and laboratorians for a rapid outbreak response is also illustrated in field investigations conducted by the CDC with state and local authorities. Finally, challenges facing health care professionals, building managers, and the public health community in combating LD are highlighted, and potential solutions are discussed.

Novel aspects on the pathogenesis of Mycoplasma pneumoniae pneumonia and therapeutic implications

Mycoplasma pneumoniae (Mp) is a leading cause of community acquired pneumonia. Knowledge regarding Mp pneumonia obtained from animal models or human subjects has been discussed in many different reports. Accumulated expertise concerning this critical issue has been hard to apply clinically, and potential problems may remain undiscovered. Therefore, our multidisciplinary team extensively reviewed the literature regarding Mp pneumonia, and compared findings from animal models with those from human subjects. In human beings, the characteristic pathological features of Mp pneumonia have been reported as alveolar infiltration with neutrophils and lymphocytes and lymphocyte/plasma cell infiltrates in the peri-bronchovascular area. Herein, we demonstrated the novel aspects of Mp pneumonia that the severity of the Mp pneumonia seemed to depend on the host innate immunity to the Mp, which might be accelerated by antecedent Mp exposure (re-exposure or latent respiratory infection) through up-regulation of Toll-like receptor 2 expression on bronchial epithelial cells and alveolar macrophages. The macrolides therapy might be beneficial for the patients with macrolide-resistant Mp pneumonia via not bacteriological but immunomodulative effects. This exhaustive review focuses on pathogenesis and extends to some therapeutic implications such as clarithromycin, and discusses the various diverse aspects of Mp pneumonia. It is our hope that this might lead to new insights into this common respiratory disease.

The bacterial aetiology of adult community-acquired pneumonia in Asia: a systematic review

BACKGROUND

Community-acquired pneumonia (CAP) is a major cause of adult mortality in Asia. Appropriate empirical treatment depends on knowledge of the pathogens commonly responsible. However, assessing the aetiological significance of identified organisms is often difficult, particularly with sputum isolates that might represent contamination with oropharyngeal flora.

METHODS

A systematic review of all adult CAP aetiology studies from Asia, excluding the Middle East, published in English between 1 January 1990 and 1 March 2012 was conducted. Forty-eight studies reporting on 10 423 patients were included, representing data from China, India, Indonesia, Japan, Malaysia, The Philippines, Singapore, South Korea, Taiwan, Thailand and Vietnam. Data from large parts of Asia were unavailable and there was substantial heterogeneity in methodology.

RESULTS

As in western studies, Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella spp. and Haemophilus influenzae were all significant pathogens. However, compared with western studies, S. pneumoniae was of less relative importance. Gram-negative bacilli and Mycobacterium tuberculosis were more important, and in northeast Thailand Burkholderia pseudomallei was a major pathogen.

CONCLUSION

These data have major implications for diagnostic strategies and empirical treatment. Narrow-spectrum antibiotics targeting S. pneumoniae may be inappropriate in many Asian settings, and agents active against TB may lead to partial response and delayed TB diagnosis.

Acute lower respiratory infections in ≥ 5 year -old hospitalized patients in Cambodia, a low-income tropical country: clinical characteristics and pathogenic etiology

Background

Few data exist on viral and bacterial etiology of acute lower respiratory infections (ALRI) in ≥5 year –old persons in the tropics.

Methods

We conducted active surveillance of community-acquired ALRI in two hospitals in Cambodia, a low-income tropical country. Patients were tested for acid-fast bacilli (AFB) by direct sputum examination, other bacteria by blood and/or sputum cultures, and respiratory viruses using molecular techniques on nasopharyngeal/throat swabs. Pulmonologists reviewed clinical/laboratory data and interpreted chest X-rays (CXR) to confirm ALRI.

Results

Between April 2007 - December 2009, 1,904 patients aged ≥5 years were admitted with acute pneumonia (50.4%), lung sequelae-associated ALRI (24.3%), isolated pleural effusions (8.9%) or normal CXR-related ALRI (17.1%); 61 (3.2%) died during hospitalization. The two former diagnoses were predominantly due to bacterial etiologies while viral detection was more frequent in the two latter diagnoses. AFB-positive accounted for 25.6% of acute pneumonia. Of the positive cultures (16.8%), abscess-prone Gram-negative bacteria (39.6%) and Haemophilus influenzae (38.0%) were most frequent, followed by Streptococcus pneumoniae (17.7%). Of the identified viruses, the three most common viruses included rhinoviruses (49.5%), respiratory syncytial virus (17.7%) and influenza viruses (12.1%) regardless of the diagnostic groups. Wheezing was associated with viral identification (31.9% vs. 13.8%, p < 0.001) independent of age and time-to-admission.

Conclusions

High frequency of H. influenzae and S. pneumoniae infections support the need for introduction of the respective vaccines in the national immunization program. Tuberculosis was frequent in patients with acute pneumonia, requiring further investigation. The relationship between respiratory viruses and wheezing merits further studies.

Community-acquired Legionella pneumophila pneumonia: a single-center experience with 214 hospitalized sporadic cases over 15 years

Legionella pneumophila has been increasingly recognized as a cause of community-acquired pneumonia (CAP) and an important public health problem worldwide. We conducted the present study to assess trends in epidemiology, diagnosis, clinical features, treatment, and outcomes of sporadic community-acquired L. pneumophila pneumonia requiring hospitalization at a university hospital over a 15-year period (1995-2010). Among 3934 nonimmunosuppressed hospitalized patients with CAP, 214 (5.4%) had L. pneumophila pneumonia (16 cases were categorized as travel-associated pneumonia, and 21 were part of small clusters). Since the introduction of the urinary antigen test, the diagnosis of L. pneumophila using this method remained stable over the years (p = 0.42); however, diagnosis by means of seroconversion and culture decreased (p < 0.001 and p = 0.001, respectively). The median age of patients with L. pneumophila pneumonia was 58.2 years (SD 13.8), and 76.4% were male. At least 1 comorbid condition was present in 119 (55.6%) patients with L. pneumophila pneumonia, mainly chronic heart disease, diabetes mellitus, and chronic pulmonary disease. The frequency of older patients (aged >65 yr) and comorbidities among patients with L. pneumophila pneumonia increased over the years (p = 0.06 and p = 0.02, respectively). In addition, 100 (46.9%) patients were classified into high-risk classes according to the Pneumonia Severity Index (groups IV-V). Twenty-four (11.2%) patients with L. pneumophila pneumonia received inappropriate empirical antibiotic therapy at hospital admission. Compared with patients who received appropriate empirical antibiotic, patients who received inappropriate therapy more frequently had acute onset of illness (p = 0.004), pleuritic chest pain (p = 0.03), and pleural effusion (p = 0.05). The number of patients who received macrolides decreased over the study period (p < 0.001), whereas the number of patients who received levofloxacin increased (p < 0.001). No significant difference was found in the outcomes between patients who received erythromycin and clarithromycin. However, compared with macrolide use during hospital admission, levofloxacin therapy was associated with a trend toward a shorter time to reach clinical stability (median, 3 vs. 5 d; p = 0.09) and a shorter length of hospital stay (median, 7 vs. 10 d; p < 0.001). Regarding outcomes, 38 (17.8%) patients required intensive care unit (ICU) admission, and the inhospital case-fatality rate was 6.1% (13 of 214 patients). The frequency of ICU admission (p = 0.34) and the need for mechanical ventilation (p = 0.57) remained stable over the study period, but the inhospital case-fatality rate decreased (p = 0.04). In the logistic regression analysis, independent factors associated with severe disease (ICU admission and death) were current/former smoker (odds ratio [OR], 2.96; 95% confidence interval [CI], 1.01-8.62), macrolide use (OR, 2.40; 95% CI, 1.03-5.56), initial inappropriate therapy (OR, 2.97; 95% CI, 1.01-8.74), and high-risk Pneumonia Severity Index classes (OR, 9.1; 95% CI, 3.52-23.4). In conclusion, L. pneumophila is a relatively frequent causative pathogen among hospitalized patients with CAP and is associated with high morbidity. The annual number of L. pneumophila cases remained stable over the study period. In recent years, there have been significant changes in diagnosis and treatment, and the inhospital case-fatality rate of L. pneumophila pneumonia has decreased.

Clinical symptoms and signs for the diagnosis of Mycoplasma pneumoniae in children and adolescents with community-acquired pneumonia

BACKGROUND

Mycoplasma pneumoniae (M. pneumoniae) is a significant cause of community-acquired pneumonia in children and adolescents. Treatment with macrolide antibiotics is recommended. However, M. pneumoniae is difficult to diagnose based on clinical symptoms and signs. Diagnostic uncertainty can lead to inappropriate antibiotic prescribing, which may worsen clinical prognosis and increase antibiotic resistance.

OBJECTIVES

The objectives of this review are (i) to assess the diagnostic accuracy of symptoms and signs in the clinical recognition of M. pneumoniae in children and adolescents with community-acquired pneumonia; and (ii) to assess the influence of potential sources of heterogeneity on the diagnostic accuracy of symptoms and signs in the clinical recognition of M. pneumoniae.

SEARCH METHODS

We searched MEDLINE (January 1950 to 26 June 2012) and EMBASE (January 1980 to 26 June 2012). We identified additional references by handsearching the reference lists of included articles and snowballing. We searched the reference lists of relevant systematic reviews identified by searching the Medion database, Database of Reviews of Effects 2012, Issue 6 (25 June 2012) and the Cochrane Register of Diagnostic Test Accuracy studies (2 July 2012). Experts in the field reviewed our list of included studies for any obvious omissions.

SELECTION CRITERIA

We included peer-reviewed published studies which prospectively and consecutively recruited children with community-acquired pneumonia from any healthcare setting, confirmed the presence of M. pneumoniae using serology with or without other laboratory methods and reported data on clinical symptoms and signs in sufficient detail to construct 2 x 2 tables.

DATA COLLECTION AND ANALYSIS

One review author scanned titles to exclude obviously irrelevant articles. Two review authors independently scanned the remaining titles and abstracts, reviewed full-text versions of potentially relevant articles, assessed the quality of included articles and extracted data on study characteristics and the following clinical features: cough, wheeze, coryza, crepitations, fever, rhonchi, shortness of breath, chest pain, diarrhea, myalgia and headache.We calculated study-specific values for sensitivity, specificity and positive and negative likelihood ratios with 95% confidence intervals (CIs). We estimated the post-test probability of M. pneumoniae based on the absence or presence of symptoms and signs.We calculated pooled sensitivities, specificities, positive and negative likelihood ratios with 95% CIs for symptoms and signs where data were reported by at least four included studies by fitting a bivariate normal model for the logit transforms of sensitivity and specificity. We explored potential sources of heterogeneity by fitting bivariate models with covariates using multi-level mixed-effects logistic regression. We performed sensitivity analyses excluding data from studies for which we were concerned about the representativeness of the study population and/or the acceptability of the reference standard.

MAIN RESULTS

Our search identified 8299 articles (excluding duplicates). We examined the titles and abstracts of 1125 articles and the full-text versions of 97 articles. We included seven studies in our review, which reported data from 1491 children; all were conducted in hospital settings. Overall, study quality was moderate. In two studies the presence of chest pain more than doubled the probability of M. pneumoniae. Wheeze was 12% more likely to be absent in children with M. pneumoniae (pooled positive likelihood ratio (LR+) 0.76, 95% CI 0.60 to 0.97; pooled negative likelihood ratio (LR-) 1.12, 95% CI 1.02 to 1.23). Our sensitivity analysis showed that the presence of crepitations was associated with M. pneumoniae, but this finding was of borderline statistical significance (pooled LR+ 1.10, 95% CI 0.99 to 1.23; pooled LR- 0.66, 95% CI 0.46 to 0.96).

AUTHORS' CONCLUSIONS

M. pneumoniae cannot be reliably diagnosed in children and adolescents with community-acquired pneumonia based on clinical symptoms and signs. Although the absence of wheeze is a statistically significant diagnostic indicator, it does not have sufficient diagnostic value to guide empirical macrolide treatment. Data from two studies suggest that the presence of chest pain more than doubles the probability of M. pneumoniae. However, further research is needed to substantiate this finding. More high quality large-scale studies in primary care settings are needed to help develop prediction rules based on epidemiological data as well as clinical and baseline patient characteristics.

A literature review and survey of childhood pneumonia etiology studies: 2000-2010

The Pneumonia Etiology Research for Child Health (PERCH) project is the largest multicountry etiology study of childhood pneumonia since the Board on Science and Technology in International Development studies of the 1980s. However, it is not the only recent or ongoing pneumonia etiology study, and even with seven sites, it cannot capture all epidemiologic settings in the developing world. Funding providers, researchers and policymakers rely on the best available evidence to strategically plan programs, new research directions and interventions. We aimed to describe the current landscape of recent pneumonia etiology studies in children under 5 years of age in the developed and developing world, as ascertained by a literature review of relevant studies with data since the year 2000 and a survey of researchers in the field of childhood pneumonia. We collected information on the study population, study design, case definitions, laboratory samples and methods and identified pathogens. A literature review identified 88 studies with child pneumonia etiology results. As of June 2010, our survey of researchers identified an additional 65 ongoing and recently completed child pneumonia etiology studies. This demonstrates the broad existing context into which the PERCH study must be placed. However, the landscape analysis also reveals a multiplicity of case definitions, levels of clinician involvement, facility types, specimen collection, and laboratory techniques. It reinforces the need for the standardization of methods and analyses for present and future pneumonia etiology studies in order to optimize their cumulative potential to accurately describe the microbial causes of childhood pneumonia.

Diagnostic and prognostic value of procalcitonin in community-acquired pneumonia

INTRODUCTION

The value of measuring procalcitonin (PCT) in patients with community-acquired pneumonia (CAP) is unclear. The aim of this study was to determine the value of PCT as a marker for microbial etiology and a predictor of outcome in CAP patients.

METHODS

A single-center observational study was conducted with CAP patients. On admission, their leukocyte count, serum C-reactive protein level, and serum PCT level were determined, and microbiological tests were performed. Patients were classified into 4 groups according to the A-DROP scoring system, which assesses the severity of CAP.

RESULTS

A total of 102 patients were enrolled. The pathogen was identified in 60 patients, and 31 patients had streptococcal pneumonia. The PCT levels were significantly higher in those patients with pneumococcal pneumonia than in those patients with other bacterial pneumonias (P < 0.0001). Multivariate regression analysis revealed that high PCT levels were associated with a pneumococcal etiology [odds ratio, 1.68; 95% confidence interval (CI): 1.02-2.81; P = 0.04] after adjustment for disease severity and demographic factors. The PCT levels were correlated with the A-DROP score (r = 0.49; P < 0.0001). The area under the curve for predicting mortality was highest for the A-DROP score (0.97; 95% CI: 0.92-0.99), followed by the area under the curve for PCT (0.82; 95% CI: 0.74-0.89) and C-reactive protein (0.77; 95% CI: 0.67-0.84).

CONCLUSIONS

High PCT levels indicate that pneumococcal pneumonia and PCT levels depend on the severity of pneumonia. PCT measurements may provide important diagnostic and prognostic information for patients with CAP.

Clinical and economic burden of community-acquired pneumonia amongst adults in the Asia-Pacific region

Community-acquired pneumonia (CAP) is an important cause of mortality and morbidity amongst adults in the Asia-Pacific region. Literature published between 1990 and May 2010 on the clinical and economic burden of CAP amongst adults in this region was reviewed. CAP is a significant health burden with significant economic impact in this region. Chronic obstructive pulmonary disease, cardiovascular disease, diabetes mellitus and advanced age were risk factors for CAP. Aetiological agents included Streptococcus pneumoniae, Klebsiella pneumoniae, Gram-negative bacteria, Mycobacterium tuberculosis, Burkholderia pseudomallei, Staphylococcus aureus and atypical pathogens (Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella spp.), with important differences in the prevalence of these pathogens within the region. Antibiotic resistance was significant but was not linked to excess mortality. Aetiological pathogens remained susceptible to newer antimicrobial agents. Rational antibiotic use is essential for preventing resistance, and increased surveillance is required to identify future trends in incidence and aetiology and to drive treatment and prevention strategies.

Community-acquired pneumonia in adults with Down syndrome. Three clinical cases and a review of the literature

John Langdon Down first described this genetic disorder known today as Down syndrome (DS), due to a trisomy of chromosome 21. The frequent appearance of respiratory infections in DS is attributed to structural and functional anomalies of the respiratory system, the presence of congenital heart malformations and IgG deficits.

We present three clinical cases of adult DS patients with community-acquired pneumonia, and a review of the literature regarding: epidemiology, prevalence, symptomatology, laboratory and radiographic findings, morbidity, mortality, clinical evolution and the importance of prevention of pneumonia in DS patients. These patients presented symptoms of acute infection of the lower respiratory tract: high fever, scanty productive cough with or without sputum, pleuritic chest pain, dyspnea, fatigue, myalgia, and other atypical symptoms. Chest radiography showed focal inflammatory condensation in the affected lung and bilateral alveolo-interstitial infiltrate. Laboratory tests showed increased values of leukocytes and C-reactive protein, deficiency of IgG and low lymphocyte CD4+.

Patients with DS are highly susceptible to lower and higher respiratory tract infection. Community physicians should take exceptional precautions on detecting respiratory symptoms in these patients, since they may result in pneumonia and bronchopneumonia. Presentation may be atypical and the complications may even lead to mortality.

Microfluidic platform versus conventional real-time polymerase chain reaction for the detection of Mycoplasma pneumoniae in respiratory specimens

Rapid, accurate diagnosis of community-acquired pneumonia (CAP) due to Mycoplasma pneumoniae is compromised by low sensitivity of culture and serology. Polymerase chain reaction (PCR) has emerged as a sensitive method to detect M. pneumoniae DNA in clinical specimens. However, conventional real-time PCR is not cost-effective for routine or outpatient implementation. Here, we evaluate a novel microfluidic real-time PCR platform (Advanced Liquid Logic, Research Triangle Park, NC) that is rapid, portable, and fully automated. We enrolled patients with CAP and extracted DNA from nasopharyngeal wash (NPW) specimens using a biotinylated capture probe and streptavidin-coupled magnetic beads. Each extract was tested for M. pneumoniae-specific DNA by real-time PCR on both conventional and microfluidic platforms using Taqman probe and primers. Three of 59 (5.0%) NPWs were positive, and agreement between the methods was 98%. The microfluidic platform was equally sensitive but 3 times faster and offers an inexpensive and convenient diagnostic test for microbial DNA.

Neumonía adquirida en la comunidad en pacientes adultos con síndrome de Down. Presentación de tres casos clínicos y revisión de la literatura

John Langdon Down fue el primero en describir el cuadro clínico de esta alteración genética caracterizada por trisomía del cromosoma 21, también conocida como síndrome de Down (SD). La frecuente aparición de infecciones respiratorias en el SD se atribuye a numerosas anomalías estructurales y funcionales, a la presencia de malformaciones congénitas cardíacas y a déficits de IgG.

Se presentan tres casos clínicos de pacientes adultos con SD que padecieron una neumonía adquirida en la comunidad y se realiza una revisión bibliográfica considerando los aspectos epidemiológicos, la prevalencia, el cuadro clínico, los datos de laboratorio y los radiológicos, la morbimortalidad, la evolución y la importancia de la prevención. Estos pacientes pueden presentar síntomas de infección aguda del aparato respiratorio bajo, como fiebre alta, tos con o sin expectoración, dolor torácico por irritación pleural, disnea, fatiga, mialgias, así como otros síntomas atípicos. La radiografía de tórax puede mostrar un foco de condensación inflamatoria en un pulmón, o un infiltrado alveolointersticial bilateral. La analítica de sangre puede mostrar leucocitosis, aumento de la proteína C reactiva, deficiencia de IgG y de los linfocitos CD4+.

Los pacientes con SD son altamente susceptibles a padecer infecciones respiratorias del tracto superior como del inferior. Los médicos deben tener especial precaución ante la presencia de síntomas respiratorios en estos pacientes, ya que en muchas ocasiones pueden desarrollar neumonías y bronconeumonías que se presentan de forma atípica y con complicaciones que se acompañan de alta mortalidad.

Atypical pneumonia--time to breathe new life into a useful term?

The term atypical pneumonia was originally used to describe an unusual presentation of pneumonia. It is now more widely used in reference to either pneumonia caused by a relatively common group of pathogens, or to a distinct clinical syndrome the existence of which is difficult to demonstrate. As such, the use of atypical pneumonia is often inaccurate, potentially confusing, and of dubious scientific merit. We need to return to the original meaning of atypical pneumonia and restrict its use to describe pneumonia that is truly unusual in clinical presentation, epidemiology, or both.

Causative agent distribution and antibiotic therapy assessment among adult patients with community acquired pneumonia in Chinese urban population

BACKGROUND

Knowledge of predominant microbial patterns in community-acquired pneumonia (CAP) constitutes the basis for initial decisions about empirical antimicrobial treatment, so a prospective study was performed during 2003-2004 among CAP of adult Chinese urban populations.

METHODS

Qualified patients were enrolled and screened for bacterial, atypical, and viral pathogens by sputum and/or blood culturing, and by antibody seroconversion test. Antibiotic treatment and patient outcome were also assessed.

RESULTS

Non-viral pathogens were found in 324/610 (53.1%) patients among whom M. pneumoniae was the most prevalent (126/610, 20.7%). Atypical pathogens were identified in 62/195 (31.8%) patients carrying bacterial pathogens. Respiratory viruses were identified in 35 (19%) of 184 randomly selected patients with adenovirus being the most common (16/184, 8.7%). The nonsusceptibility of S. pneumoniae to penicillin and azithromycin was 22.2% (Resistance (R): 3.2%, Intermediate (I): 19.0%) and 79.4% (R: 79.4%, I: 0%), respectively. Of patients (312) from whom causative pathogens were identified and antibiotic treatments were recorded, clinical cure rate with beta-lactam antibiotics alone and with combination of a beta-lactam plus a macrolide or with fluoroquinolones was 63.7% (79/124) and 67%(126/188), respectively. For patients having mixed M. pneumoniae and/or C. pneumoniae infections, a better cure rate was observed with regimens that are active against atypical pathogens (e.g. a beta-lactam plus a macrolide, or a fluoroquinolone) than with beta-lactam alone (75.8% vs. 42.9%, p = 0.045).

CONCLUSION

In Chinese adult CAP patients, M. pneumoniae was the most prevalent with mixed infections containing atypical pathogens being frequently observed. With S. pneumoniae, the prevalence of macrolide resistance was high and penicillin resistance low compared with data reported in other regions.

Antimicrobial susceptibility of Mycoplasma pneumoniae isolates and molecular analysis of macrolide-resistant strains from Shanghai, China

Fifty-three Mycoplasma pneumoniae strains were isolated from pediatric patients in Shanghai, China, from October 2005 to February 2008. Of 53 clinical isolates, 44 (83%) were resistant to erythromycin (MICs of >128 microg/ml for all 44 strains), azithromycin, and clarithromycin. All macrolide-resistant M. pneumoniae strains harbored an A-to-G transition mutation at position 2063 in 23S rRNA genes. Forty-five (85%) clinical isolates were classified into the P1 gene restriction fragment length polymorphism type I, and six (11%) were type II.

Pediatric respiratory infections by Mycoplasma pneumoniae

Mycoplasma pneumoniae is one of the most common agents of community-acquired pneumonia in children and young adults. Although M. pneumoniae is a small bacterium that can reproduce in an artificial culture medium and is known to be sensitive to certain antibiotics in vitro as well as in vivo, the immunopathogenesis of M. pneumoniae in the human host is not fully understood. The epidemiologic characteristics, including periodic epidemics, and some clinical characteristics of M. pneumoniae are similar to those observed in systemic viral infections. Many experimental and clinical studies have suggested that the pathogenesis of lung injuries in M. pneumoniae infection is associated with a cell-mediated immune reaction, including high responsiveness to corticosteroid therapy. This paper presents an overview of M. pneumoniae infections, with emphasis on epidemiology, pathogenesis and treatment.