Etiological analysis and predictive diagnostic model building of community-acquired pneumonia in adult outpatients in Beijing, China

Acute cough in outpatients: what causes it, how long does it last, and how severe is it for different viruses and bacteria?

OBJECTIVES

To describe the symptoms, duration, severity, and microbiology of lower respiratory tract infection (LRTI) in outpatients.

METHODS

Prospective cohort study of adults in US primary or urgent care with a chief complaint of cough and symptoms consistent with LRTI. Baseline data included demographics, signs, symptoms and PCR for 46 viruses and bacteria. Severity of symptoms reported for up to 28 days follow-up via diary and text message. The Bronchitis Severity Score (BSS) assessed severity at baseline; overall severity was defined as the area under the symptom severity curve.

RESULTS

Of 718 patients with complete baseline data, 618 had valid PCR results, and 443 were followed until symptoms resolved. Of those with valid PCR, 100 (16.2%) had 1+ viruses detected, 211 (34.1%) had 1+ bacteria, and 168 (27.2%) had both. Symptoms more likely with viral or mixed infection included feverishness (36.7% to 38.4% vs 18.5%), chills or sweats (36.0% to 38.1% vs 17.9%), being generally unwell (78.2% to 81.3% vs 64.9%), and myalgias (42.7% to 48.2% vs 28.6%). Colored sputum (42.9% vs 23.2% to 29.5%) was more common with bacterial infection. Mean duration of cough was 14.7 days with viruses (95% CI 13.2-16.2), 17.3 with bacteria (95% CI 15.9-18.6), 16.9 with mixed infection (95% CI 15.2-18.6), and 18.4 with no detection (95% CI 16.1-20.8). Overall severity of cough was lower for viral infections (20.9 points, 95% CI 18.6-23.3) than for other groups (range 24.2-26.3). The most common potential bacterial pathogens were Haemophilus influenza (28.0%), Moraxella catarrhalis (16.2%), and Streptococcus pneumoniae (10.2%), while the most common viral pathogens were rhinovirus (17.3%), influenza (12.8%), SARS-CoV-2 (11.5%), and seasonal coronaviruses (8.1%).

CONCLUSION

The mean duration of cough was 16.4 days. Consistent with European studies, the type of infection or potential pathogen was not an important predictor of the duration or severity of LRTI.

Colonization of bacterial and viral respiratory pathogens among healthcare workers in China during COVID-19 pandemic

Background

Healthcare settings may amplify transmission of respiratory pathogens, however empirical evidence is lacking. We aimed to describe the spectrum and distribution of respiratory pathogens among healthcare workers in eastern China.

Methods

Healthcare workers were recruited from October 2020 to November 2021 in Jiangsu province. Participants were interviewed regarding demographic and hospital-based protective measures. Thirty-seven common respiratory pathogens were tested using real-time PCR/RT-PCR (Probe qPCR). The role of demographic and hospital-based protective measures on pathogens colonization using multivariable logistic regression models.

Results

Among 316 enrolled healthcare workers, a total of 21 pathogens were detected. In total, 212 (67.1%) healthcare workers had at least one respiratory pathogen; 195 (61.7%) and 70 (22.2%) with a bacterial and viral pathogen. The most commonly detected pathogen was streptococcus pneumoniae (47.5%) followed by Haemophilus influenzae (21.2%). One hundred and five (33.2%) healthcare workers with copathogens had at least two respiratory pathogens. Both bacterial and viral colonization were more common in 2020 compared to 2021. A decreased risk of colonization was seen in participants with infection prevention and control training and suitable hand hygiene.

Conclusions

Colonization of respiratory pathogens in healthcare workers from eastern China was high. Differential risk was impacted only by hospital-based protective measures and not demographic factors.

Disease burden and macrolide resistance of Mycoplasma pneumoniae infection in adults in the Asia-Pacific region

OBJECTIVES

In the Asia-Pacific region, Mycoplasma pneumoniae (MP) could be a notable pathogen responsible for adult community-acquired pneumonia (CAP), with varying prevalence rates. This comprehensive review aimed to explore the epidemiology, clinical manifestations, macrolide resistance, and molecular characteristics of MP in adults across several countries in Asia.

METHODS

PubMed, Embase, and Google Scholar were searched for relevant articles from 2010-2023 based on the following keywords: adult and Mycoplasma pneumoniae.

RESULTS

The prevalence of MP in CAP patients in these countries ranged from 2.1% in Korea to 25.5% in Japan. Macrolide resistance was prominent, particularly in China, with rates ranging 26.9-100%. Clinical manifestations of MP infection included protean extrapulmonary manifestations, and complications such as rhabdomyolysis and thrombocytopenia. Molecular characteristics, especially the multiple locus variable-number tandem-repeat analysis type 4/5/7/2, remained predominant across various countries, emphasising the importance of ongoing surveillance.

CONCLUSIONS

This review highlights the urgent need for continued monitoring of MP infections, macrolide resistance, and molecular characteristics to inform effective prevention and treatment strategies in the Asia-Pacific region.

Impact of Metagenomic Next-Generation Sequencing of Bronchoalveolar Lavage Fluid on Antimicrobial Stewardship in Patients With Lower Respiratory Tract Infections: A Retrospective Cohort Study

BACKGROUND

The impact of metagenomic next-generation sequencing (mNGS) on antimicrobial stewardship in patients with lower respiratory tract infections (LRTIs) is still unknown.

METHODS

This retrospective cohort study included patients who had LRTIs diagnosed and underwent bronchoalveolar lavage between September 2019 and December 2020. Patients who underwent both mNGS and conventional microbiologic tests were classified as the mNGS group, while those with conventional tests only were included as a control group. A 1:1 propensity score match for baseline variables was conducted, after which changes in antimicrobial stewardship between the 2 groups were assessed.

RESULTS

A total of 681 patients who had an initial diagnosis of LRTIs and underwent bronchoalveolar lavage were evaluated; 306 patients were finally included, with 153 in each group. mNGS was associated with lower rates of antibiotic escalation than in the control group (adjusted odds ratio, 0.466 [95% confidence interval, .237-.919]; P = .02), but there was no association with antibiotic de-escalation. Compared with the control group, more patients discontinued the use of antivirals in the mNGS group.

CONCLUSIONS

The use of mNGS was associated with lower rates of antibiotic escalation and may facilitate the cessation of antivirals, but not contribute to antibiotic de-escalation in patients with LRTIs.

Predicting Mycoplasma pneumoniae and Chlamydophila pneumoniae in community-acquired pneumonia (CAP) pneumonia: epidemiological study of respiratory tract infection using multiplex PCR assays

Community-acquired pneumonia (CAP) is a common illness that can lead to mortality. β-lactams are ineffective against atypical pathogen including Mycoplasma pneumoniae. We used molecular examinations to develop a decision tree to predict atypical pathogens with CAP and to examine the prevalence of macrolide resistance in Mycoplasma pneumoniae. We conducted a prospective observational study of patients aged ≥ 18 years who had fever and respiratory symptoms and were diagnosed with CAP in one of two community hospitals between December 2016 and October 2018. We assessed combinations of clinical variables that best predicted atypical pathogens with CAP by classification and regression tree (CART) analysis. Pneumonia was defined as respiratory symptoms and new infiltration recognized on chest X-ray or chest computed tomography. We analyzed 47 patients (21 females, 44.7%, mean age: 47.6 years). Atypical pathogens were detected in 15 patients (31.9%; 12 Mycoplasma pneumoniae, 3 Chlamydophila pneumoniae). Ten patients carried macrolide resistant Mycoplasma pneumoniae (macrolide resistant rate 83.3%). CART analysis suggested that factors associated with presence of atypical pathogens were absence of crackles, age < 45 years, and LD ≥ 183 U/L (sensitivity 86.7% [59.5, 98.3], specificity 96.9% [83.8, 99.9]). ur simple clinical decision rules can be used to identify primary care patients with CAP that are at risk for atypical pathogens. Further research is needed to validate its usefulness in various populations.Trial registration Clinical Trial (UMIN trial ID: UMIN000035346).

Incidence, Etiology, and Environmental Risk Factors of Community-Acquired Pneumonia Requiring Hospitalization in China: A 3-Year, Prospective, Age-Stratified, Multicenter Case-Control Study

Background

Community-acquired pneumonia (CAP) is a leading infectious cause of hospitalization and death worldwide. Knowledge about the incidence and etiology of CAP in China is fragmented.

Methods

A multicenter study performed at 4 hospitals in 4 regions in China and clinical samples from CAP patients were collected and used for pathogen identification from July 2016 to June 2019.

Results

A total of 1674 patients were enrolled and the average annual incidence of hospitalized CAP was 18.7 (95% confidence interval, 18.5-19.0) cases per 10000 people. The most common viral and bacterial agents found in patients were respiratory syncytial virus (19.2%) and Streptococcus pneumoniae (9.3%). The coinfections percentage was 13.8%. Pathogen distribution displayed variations within age groups as well as seasonal and regional differences. The severe acute respiratory syndrome coronavirus 2 was not detected. Respiratory virus detection was significantly positively correlated with air pollutants (including particulate matter ≤2.5 µm, particulate matter ≤10 µm, nitrogen dioxide, and sulfur dioxide) and significantly negatively correlated with ambient temperature and ozone content; bacteria detection was opposite.

Conclusions

The hospitalized CAP incidence in China was higher than previously known. CAP etiology showed that differences in age, seasons, regions, and respiratory viruses were detected at a higher rate than bacterial infection overall. Air pollutants and temperature have an influence on the detection of pathogens.

Hospital utilization rates for influenza and RSV: a novel approach and critical assessment

BACKGROUND

Influenza and respiratory syncytial virus (RSV) contribute significantly to the burden of acute lower respiratory infection (ALRI) inpatient care, but heterogeneous coding practices and availability of inpatient data make it difficult to estimate global hospital utilization for either disease based on coded diagnoses alone.

METHODS

This study estimates rates of influenza and RSV hospitalization by calculating the proportion of ALRI due to influenza and RSV and applying this proportion to inpatient admissions with ALRI coded as primary diagnosis. Proportions of ALRI attributed to influenza and RSV were extracted from a meta-analysis of 360 total sources describing inpatient hospital admissions which were input to a Bayesian mixed effects model over age with random effects over location. Results of this model were applied to inpatient admission datasets for 44 countries to produce rates of hospital utilization for influenza and RSV respectively, and rates were compared to raw coded admissions for each disease.

RESULTS

For most age groups, these methods estimated a higher national admission rate than the rate of directly coded influenza or RSV admissions in the same inpatient sources. In many inpatient sources, International Classification of Disease (ICD) coding detail was insufficient to estimate RSV burden directly. The influenza inpatient burden estimates in older adults appear to be substantially underestimated using this method on primary diagnoses alone. Application of the mixed effects model reduced heterogeneity between countries in influenza and RSV which was biased by coding practices and between-country variation.

CONCLUSIONS

This new method presents the opportunity of estimating hospital utilization rates for influenza and RSV using a wide range of clinical databases. Estimates generally seem promising for influenza and RSV associated hospitalization, but influenza estimates from primary diagnosis seem highly underestimated among older adults. Considerable heterogeneity remains between countries in ALRI coding (i.e., primary vs non-primary cause), and in the age profile of proportion positive for influenza and RSV across studies. While this analysis is interesting because of its wide data utilization and applicability in locations without laboratory-confirmed admission data, understanding the sources of variability and data quality will be essential in future applications of these methods.

Multiplex Tests for Respiratory Tract Infections: The Direct Utility of the FilmArray Respiratory Panel in Emergency Department

Background

The FilmArray Respiratory Panel with multiplex targets for respiratory pathogens has been widely used and verified in clinical trials in special test settings. However, it is necessary to evaluate the panel's performance at the point of care directly, in nonspecific test settings.

Methods

Patients with respiratory tract infections were enrolled from among emergency department visitors, and all steps, including the collection of specimens and testing, were performed by our clinicians.

Results

Among 270 patients, 196 (72.6%) patients were found to have one or more pathogens. For signal pathogen detection, influenza A virus had the highest rate of detection; 45 (16.7%) of the patients had two or more respiratory pathogens codetected, and most of the multiplex pathogens were rhinovirus/enterovirus codetected with Bordetella pertussis (17.8%). The information provided by the FilmArray had an impact on the prescription of antimicrobials, and there were differences in the rates of antibiotic prescriptions and anti-influenza prescriptions among patients.

Conclusions

Use of the FilmArray by clinical staff was successfully implemented in the emergency department for the first time in China. The FilmArray has the potential for point-of-care testing in nonspecific settings.

Efficacy and Safety of Nemonoxacin in Outpatients with Community-Acquired Pneumonia

PURPOSE

To evaluate the efficacy and safety of 500 mg of nemonoxacin administered orally once daily to outpatients with community-acquired pneumonia (CAP).

PATIENTS AND METHODS

Patients with CAP who received nemonoxacin monotherapy were selected from outpatients who visited the Department of Pulmonary and Critical Care Medicine of Shengjing Hospital of China Medical University between July and December 2018. Their characteristics, pneumonia-related symptoms, treatment effects, and adverse reactions were recorded.

RESULTS

In total, 337 patients with CAP were administered 500 mg of nemonoxacin orally once daily for 8.24 ± 3.73 days. Fourteen patients were lost during the follow-up period. At the end of the follow-up period, information on 323 patients (132 males and 191 females) with a median age of 52 (P25, P75: 34, 61) years was collected. On the basis of CRB-65 scores, 273 and 50 cases were classified to have low and intermediate risks, respectively. After 3 days of treatment, the symptom improvement rate was 61.3% (198 patients). Improved symptoms or cures were evident in 98.14% (317 patients) of the patients after treatment was completed. Five (1.55%) patients were hospitalized for poor treatment efficacy, and one (0.31%) patient was diagnosed with lung cancer despite improved symptoms. During oral therapy, there were three cases of skin and three cases of gastrointestinal adverse events, an incidence of 1.86%. Based on subsequent re-examinations and telephonic follow-ups, 93.50% (302 cases) of patients were satisfied with treatment effects.

CONCLUSION

In treating outpatients with mild-to-moderate CAP, nemonoxacin can effectively control symptoms, reducing medical costs and saving patient time. Importantly, this is a safe and effective therapeutic approach as it is well tolerated with few side effects.

Diagnostic value of quantitative MP-IgG for Mycoplasma pneumoniae pneumonia in adults

The passive particle agglutination (PA) test, once widely used for Mycoplasma pneumoniae (M. pneumoniae) antibody detection, has gradually been replaced by quantitative enzyme-linked immunosorbent assays (ELISA). However, the lack of diagnostic criteria for quantitative ELISA M. pneumoniae-IgG (MP-IgG) and the low positive rates of ELISA M. pneumoniae-IgM (MP-IgM) limit the diagnostic value of ELISA for M. pneumoniae infection in adults. Here, the diagnostic value of quantitative ELISA MP-IgG was evaluated in adults with Mycoplasma pneumoniae pneumonia (MPP). The serum M. pneumoniae antibodies were detected in 162 patients with MPP, 228 patients with community-acquired pneumonia (CAP) with non-Mycoplasma pneumoniae (NMP), and 162 healthy controls by ELISA, using the PA results as the reference standards. For the MP-IgM-/IgG+ subgroup, a single serum MP-IgG level of ≥92.67 RU/mL can be used as a reference criterion for the diagnosis of acute M. pneumoniae infection. At admission, for patients with CAP, the sensitivity and specificity of ELISA MP-IgM positivity for MPP were 18.51% and 99.56%, respectively. MP-IgM positivity combined with MP-IgG ≥ 92.67 RU/mL increased the sensitivity to 40.12% and decreased the specificity to 94.29%. For paired serum samples obtained within seven days, an ELISA MP-IgG concentration change of ≥1.48-fold and MP-IgG ≥ 92.67 RU/mL on day 7 were used as the diagnostic criteria for M. pneumoniae infection. Accordingly, the combination of qualitative MP-IgM detection and quantitative MP-IgG detection by ELISA is valuable for acute MPP diagnosis in adults.

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.

Respiratory viruses in adults hospitalised with Community-Acquired Pneumonia during the non-winter months in Melbourne: Routine diagnostic practice may miss large numbers of influenza and respiratory syncytial virus infections

Background Community-Acquired Pneumonia (CAP) is one of the highest health burden conditions in Australia. Disease notifications and other data from routine diagnosis suffers from selection bias that may misrepresent the true contribution of various aetiological agents. However existing Australian prospective studies of CAP aetiology have either under-represented elderly patients, not utilised Polymerase Chain Reaction (PCR) diagnostics or been limited to winter months. We therefore sought to re-evaluate CAP aetiology by systematically applying multiplex PCR in a representative cohort of mostly elderly patients hospitalised in Melbourne during non-winter months and compare diagnostic results with those obtained under usual conditions of care. Methods Seventy two CAP inpatients were prospectively enrolled over 2 ten-week blocks during non-winter months in Melbourne in 2016-17. Nasopharyngeal and oropharyngeal swabs were obtained at admission and analysed by multiplex-PCR for 7 respiratory viruses and 5 atypical bacteria. Results Median age was 74 (interquartile range 67-80) years, with 38 (52.8%) males and 34 (47.2%) females. PCR was positive in 24 (33.3%), including 12 Picornavirus (50.5% of those with a virus), 4 RSV (16.7%) and 4 influenza A (16.7%). CAP-Sym questionnaire responses were similar in those with and without viral infections. Most (80%) pathogens detected by the study, including all 8 cases of influenza and RSV, were not otherwise detected by treating clinicians during hospital admission. Conclusion One third of patients admitted with CAP during non-winter months had PCR-detectable respiratory viral infections, including many cases of influenza and RSV that were missed by existing routine clinical diagnostic processes. Keywords: Lower Respiratory Tract Infection (LRTI), Community-Acquired Pneumonia (CAP) Polymerase Chain Reaction (PCR), Influenza, Respiratory Syncytial Virus

Pneumonia

Pneumonia remains the main cause of morbidity and mortality from infectious diseases in the world. The important reason for the increased global mortality is the impact of pneumonia on chronic diseases especially in the elderly population and the virulence factors of the causative microorganisms. Because elderly individuals present with comorbidities, particular attention should be paid for multidrug-resistant pathogens. Streptococcus pneumoniae remains the most frequently encountered pathogen. Enteric gram-negative rods, as well as anaerobes, should be considered in patients with aspiration pneumonia. Interventions for modifiable risk factors will reduce the risk of this infection. The adequacy of the initial antimicrobial therapy and determination of patients’ follow-up place is a key factor for prognosis. Also, vaccination is one of the most important preventive measures. In this section it was focused on several aspects, including the atypical presentation of pneumonia in the elderly, the methods to evaluate the severity of illness, the appropriate take care place and the management with prevention strategies.

Effects of a clinical pathway on antibiotic use in patients with community-acquired pneumonia: a multi-site study in China

BACKGROUND

Community-acquired pneumonia (CAP) is a common condition with high mortality, morbidity and healthcare costs. This study aimed to determine whether clinical pathway (CP) implementation in different hospitals in China increased antibiotic compliance with the national CP in inpatients with CAP.

METHODS

Chart reviews of CAP cases were conducted in 18 public hospitals from 3 different regions of China in 2015. Chi-square tests and the t-test were used to compare differences between hospitals that implemented CP (CP group) and those that did not (non-CP group). Multivariate logistic analysis was adopted to test whether CP implementation for CAP in hospitals affected their overall antibiotic use compliance rates with the national CP for CAP.

RESULTS

The overall compliance rate with the national CP for inpatients with CAP was 43.69%. The compliance rates for timely initial antibiotic use, recommended antibiotic use and use of the recommended combination of antibiotics and the overall compliance rate were substantially higher in the CP group than in the non-CP group. A multivariate logistic model for overall compliance in inpatients with CAP showed that the hospitals in the CP group had greater overall compliance than those in the non-CP group (odds ratio [OR] = 1.76; 95% confidence interval [CI] = 1.16-2.71) after controlling for hospital and inpatient characteristics.

CONCLUSION

In China, the overall compliance rate with the national CP for inpatients with CAP was low, but inpatients with CAP in the hospitals in the CP group received antibiotics more concordantly with the national CP. Since adherence to evidence-based care has been shown to improve clinical outcomes, internal and external support from hospitals is required to facilitate CP implementation for inpatients with CAP. Additionally, governmental commitment, hospital input and population involvement are required to improve antibiotic utilization.

Diagnosis and treatment of community-acquired pneumonia in adults: 2016 clinical practice guidelines by the Chinese Thoracic Society, Chinese Medical Association

Community‐acquired pneumonia (CAP) in adults is an infectious disease with high morbidity in China and the rest of the world. With the changing pattern in the etiological profile of CAP and advances in medical techniques in diagnosis and treatment over time, Chinese Thoracic Society of Chinese Medical Association updated its CAP guideline in 2016 to address the standard management of CAP in Chinese adults. Extensive and comprehensive literature search was made to collect the data and evidence for experts to review and evaluate the level of evidence. Corresponding recommendations are provided appropriately based on the level of evidence. This updated guideline covers comprehensive topics on CAP, including aetiology, antimicrobial resistance profile, diagnosis, empirical and targeted treatments, adjunctive and supportive therapies, as well as prophylaxis. The recommendations may help clinicians manage CAP patients more effectively and efficiently. CAP in pediatric patients and immunocompromised adults is beyond the scope of this guideline. This guideline is only applicable for the immunocompetent CAP patients aged 18 years and older. The recommendations on selection of antimicrobial agents and the dosing regimens are not mandatory. The clinicians are recommended to prescribe and adjust antimicrobial therapies primarily based on their local etiological profile and results of susceptibility testing, with reference to this guideline.

Etiological analysis and epidemiological comparison among adult CAP and NHCAP patients in Okinawa, Japan

BACKGROUND

Etiological epidemiology and diagnosis are important issues for CAP and NHCAP. Despite the availability of effective therapies, significant morbidity and mortality ensues.

METHODS

We retrospectively analyzed the etiology of 200 pneumonia patients at the University of the Ryukyus Hospital. Patients were categorized into CAP (n = 97) or NHCAP (n = 103), according to the Japanese Respiratory Society guidelines. Diagnoses were made using clinical tests including, Gram stain, bacterial culture, serum and urinary tests.

RESULTS

Pathogens were detected in 71% of patients, and identified as the source of infection in 52% (104/200). The majority of patients suffered from Streptococcus pneumoniae (32/200), Haemophilus influenzae (22/200), and Moraxella catarrhalis (16/200). Gram stain guided pathogen-oriented therapy decisions for 38 of 96 patients with unknown pathogens. Atypical pathogens were only diagnosed in CAP patients (n = 5). Severity of pneumonia was related to male sex (p = 0.006), and preexisting conditions, such as chronic heart failure (p < 0.001) and COPD (p < 0.001). Risk factors associated with increased length of stay included chronic heart failure, chronic renal failure, other pulmonary diseases and diabetes. Mortality for NHCAP patients was associated with lung cancer and bronchiectasis. CAP patients were more frequently admitted during winter months, while NHCAP patients were admitted during all other seasons. Seasonal patterns for individual pathogens could not be determined.

CONCLUSION

Gram staining remains useful to guiding diagnostics. Pathogens affecting CAP and NHCAP patients were not significantly different; as such, attention should be focused on the management of underlying conditions. Clinical outcomes were not affected by guideline discordant therapy.

Microbial Etiology of Pneumonia: Epidemiology, Diagnosis and Resistance Patterns

Globally, pneumonia is a serious public health concern and a major cause of mortality and morbidity. Despite advances in antimicrobial therapies, microbiological diagnostic tests and prevention measures, pneumonia remains the main cause of death from infectious disease in the world. An important reason for the increased global mortality is the impact of pneumonia on chronic diseases, along with the increasing age of the population and the virulence factors of the causative microorganism. The increasing number of multidrug-resistant bacteria, difficult-to-treat microorganisms, and the emergence of new pathogens are a major problem for clinicians when deciding antimicrobial therapy. A key factor for managing and effectively guiding appropriate antimicrobial therapy is an understanding of the role of the different causative microorganisms in the etiology of pneumonia, since it has been shown that the adequacy of initial antimicrobial therapy is a key factor for prognosis in pneumonia. Furthermore, broad-spectrum antibiotic therapies are sometimes given until microbiological results are available and de-escalation cannot be performed quickly. This review provides an overview of microbial etiology, resistance patterns, epidemiology and microbial diagnosis of pneumonia.

Identification of pathogens by comprehensive real-time PCR versus conventional methods in community-acquired pneumonia in Japanese adults

BACKGROUND

Community-acquired pneumonia (CAP) has high morbidity and mortality. Unfortunately, the pathogen detection rate using conventional culture methods is relatively low. We compared comprehensive real-time polymerase chain reaction (real-time PCR) analysis of nasopharyngeal swab specimens (NPS) and sputum samples against conventional methods for ability to detect causative pathogens of CAP.

METHODS

We prospectively enrolled adult CAP patients, including those with prior antibiotic use, from December 2012 to May 2014. For each patient, causative pathogens were investigated conventionally and by real-time PCR that can identify 6 bacterial and 11 viral pathogens.

RESULTS

Patients numbered 92 (mean age, 63 years; 59 male), including 30 (33%) with prior antibiotic use. Considering all patients, identification of causative pathogens by real-time PCR was significantly more frequent than by conventional methods in all patients (72% vs. 57%, p = 0.018). In patients with prior antibiotic use, identification rates also differed significantly (PCR, 77%; conventional, 50%; p = 0.027). Mixed infections were more frequent according to real-time PCR than conventional methods (26% vs. 4%, p < 0.001). By the real-time PCR, Streptococcus pneumoniae was most frequently identified (38%) as a causative pathogen, followed by Haemophilus influenzae (37%) and Mycoplasma pneumoniae (5%). PCR also identified viral pathogens (21%), with sensitivity enhanced by simultaneous examination of both NPS and sputum samples rather than only NPS samples.

CONCLUSIONS

Real-time PCR of NPS and sputum samples could better identify bacterial and viral pathogens in CAP than conventional methods, both overall and in patients with prior antibiotic treatment.

Review of Non-Bacterial Infections in Respiratory Medicine: Viral Pneumonia

Although bacteria are the main pathogens involved in community-acquired pneumonia, a significant number of community-acquired pneumonia are caused by viruses, either directly or as part of a co-infection. The clinical picture of these different pneumonias can be very similar, but viral infection is more common in the pediatric and geriatric populations, leukocytes are not generally elevated, fever is variable, and upper respiratory tract symptoms often occur; procalcitonin levels are not generally affected. For years, the diagnosis of viral pneumonia was based on cell culture and antigen detection, but since the introduction of polymerase chain reaction techniques in the clinical setting, identification of these pathogens has increased and new microorganisms such as human bocavirus have been discovered. In general, influenza virus type A and syncytial respiratory virus are still the main pathogens involved in this entity. However, in recent years, outbreaks of deadly coronavirus and zoonotic influenza virus have demonstrated the need for constant alert in the face of new emerging pathogens. Neuraminidase inhibitors for viral pneumonia have been shown to reduce transmission in cases of exposure and to improve the clinical progress of patients in intensive care; their use in common infections is not recommended. Ribavirin has been used in children with syncytial respiratory virus, and in immunosuppressed subjects. Apart from these drugs, no antiviral has been shown to be effective. Prevention with anti-influenza virus vaccination and with monoclonal antibodies, in the case of syncytial respiratory virus, may reduce the incidence of pneumonia.

Polymicrobial community-acquired pneumonia: An emerging entity

Polymicrobial aetiology in community-acquired pneumonia (CAP) is more common than previously recognized. This growing new entity can influence inflammation, host immunity and disease outcomes in CAP patients. However, the true incidence is complicated to determine and probably underestimated due mainly to many cases going undetected, particularly in the outpatient setting, as the diagnostic yield is restricted by the sensitivity of currently available microbiologic tests and the ability to get certain types of clinical specimens. The observed rate of polymicrobial cases may also lead to new antibiotic therapy considerations. In this review, we discuss the pathogenesis, microbial interactions in pneumonia, epidemiology, biomarkers and antibiotic therapy for polymicrobial CAP.

Diagnostic accuracy of C-reactive protein and procalcitonin in suspected community-acquired pneumonia adults visiting emergency department and having a systematic thoracic CT scan

Introduction

Community-acquired pneumonia (CAP) requires prompt treatment, but its diagnosis is complex. Improvement of bacterial CAP diagnosis by biomarkers has been evaluated using chest X-ray infiltrate as the CAP gold standard, producing conflicting results. We analyzed the diagnostic accuracy of biomarkers in suspected CAP adults visiting emergency departments for whom CAP diagnosis was established by an adjudication committee which founded its judgment on a systematic multidetector thoracic CT scan.

Methods

In an ancillary study of a multi-center prospective study evaluating the impact of systematic thoracic CT scan on CAP diagnosis, sensitivity and specificity of C-reactive protein (CRP) and procalcitonin (PCT) were evaluated. Systematic nasopharyngeal multiplex respiratory virus PCR was performed at inclusion. An adjudication committee classified CAP diagnostic probability on a 4-level Likert scale, based on all available data.

Results

Two hundred patients with suspected CAP were analyzed. The adjudication committee classified 98 patients (49.0 %) as definite CAP, 8 (4.0 %) as probable, 23 (11.5 %) as possible and excluded in 71 (35.5 %, including 29 patients with pulmonary infiltrates on chest X-ray). Among patients with radiological pulmonary infiltrate, 23 % were finally classified as excluded. Viruses were identified by PCR in 29 % of patients classified as definite. Area under the curve was 0.787 [95 % confidence interval (95 % CI), 0.717 to 0.857] for CRP and 0.655 (95 % CI, 0.570 to 0.739) for PCT to detect definite CAP. CRP threshold at 50 mg/L resulted in a positive predictive value of 0.76 and a negative predictive value of 0.75. No PCT cut-off resulted in satisfactory positive or negative predictive values. CRP and PCT accuracy was not improved by exclusion of the 25 (25.5 %) definite viral CAP cases.

Conclusions

For patients with suspected CAP visiting emergency departments, diagnostic accuracy of CRP and PCT are insufficient to confirm the CAP diagnosis established using a gold standard that includes thoracic CT scan. Diagnostic accuracy of these biomarkers is also insufficient to distinguish bacterial CAP from viral CAP.

Trial registration

ClinicalTrials.gov registry NCT01574066 (February 7, 2012)

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1083-6) contains supplementary material, which is available to authorized users.

Clinical data analysis of 19 cases of community-acquired adenovirus pneumonia in immunocompetent adults

The aim of this study was to investigate the characteristics of clinical manifestations, laboratory tests and imaging changes of community-acquired adenovirus pneumonia in immunocompetent adults. A retrospective study was performed on 19 adult community-acquired adenovirus pneumonia cases in Yantai, whereby the clinical data were collected and analyzed. Of 19 cases, 14 (73.68%) had fever and 17 (89.47%) had cough symptoms. Moreover, 14 cases (73.68%) had normal white blood cell counts, while 11 cases (57.89%) exhibited a reduction in lymphocyte proportion. Among the 19 cases, 17 cases exhibited lesions in a single lung, while 2 cases involved bilateral lungs. The lesions predominantly exhibited ground glass-like changes. The clinical manifestations of adult community-acquired adenovirus pneumonia patients with normal immune functions were mild, with such presenting symptoms as fever, cough, and sputum; most patients did not exhibit high levels of white blood cells or low lymphocyte counts, and the imaging features (ground glass-like effusion) were indicative of single-lung involvement.

Review of Non-Bacterial Infections in Respiratory Medicine: Viral Pneumonia

Although bacteria are the main pathogens involved in community-acquired pneumonia, a significant number of community-acquired pneumonia are caused by viruses, either directly or as part of a co-infection. The clinical picture of these different pneumonias can be very similar, but viral infection is more common in the pediatric and geriatric populations, leukocytes are not generally elevated, fever is variable, and upper respiratory tract symptoms often occur; procalcitonin levels are not generally affected. For years, the diagnosis of viral pneumonia was based on cell culture and antigen detection, but since the introduction of polymerase chain reaction techniques in the clinical setting, identification of these pathogens has increased and new microorganisms such as human bocavirus have been discovered. In general, influenza virus type A and syncytial respiratory virus are still the main pathogens involved in this entity. However, in recent years, outbreaks of deadly coronavirus and zoonotic influenza virus have demonstrated the need for constant alert in the face of new emerging pathogens. Neuraminidase inhibitors for viral pneumonia have been shown to reduce transmission in cases of exposure and to improve the clinical progress of patients in intensive care; their use in common infections is not recommended. Ribavirin has been used in children with syncytial respiratory virus, and in immunosuppressed subjects. Apart from these drugs, no antiviral has been shown to be effective. Prevention with anti-influenza virus vaccination and with monoclonal antibodies, in the case of syncytial respiratory virus, may reduce the incidence of pneumonia.

Viruses detected by systematic multiplex polymerase chain reaction in adults with suspected community-acquired pneumonia attending emergency departments in France

Infectious agents associated with community-acquired pneumonia (CAP) are under-studied. This study attempted to identify viruses from the upper respiratory tract in adults visiting emergency departments for clinically suspected CAP. Adults with suspected CAP enrolled in the ESCAPED study (impact of computed tomography on CAP diagnosis) had prospective nasopharyngeal (NP) samples studied by multiplex PCR (targeting 15 viruses and four intracellular bacteria). An adjudication committee composed of infectious disease specialists, pneumologists and radiologists blinded to PCR results reviewed patient records, including computed tomography and day 28 follow up, to categorize final diagnostic probability of CAP as definite, probable, possible, or excluded. Among the 254 patients enrolled, 78 (31%) had positive PCR, which detected viruses in 72/254 (28%) and intracellular bacteria in 8 (3%) patients. PCR was positive in 44/125 (35%) patients with definite CAP and 21/83 (25%) patients with excluded CAP. The most frequent organisms were influenza A/B virus in 27 (11%), rhinovirus in 20 (8%), coronavirus in seven (3%), respiratory syncytial virus in seven (3%) and Mycoplasma pneumoniae in eight (3%) of 254 patients. Proportion of rhinovirus was higher in patients with excluded CAP compared with other diagnostic categories (p = 0.01). No such difference was observed for influenza virus. Viruses seem common in adults attending emergency departments with suspected CAP. A concomitant clinical, radiological and biological analysis of the patient's chart can contribute to either confirm their role, or suggest upper respiratory tract infection or shedding. Their imputability and impact in early management of CAP deserve further studies.

CLINICAL TRIALS REGISTRATION

NCT01574066.

Bacterial etiologies of five core syndromes: laboratory-based syndromic surveillance conducted in Guangxi, China

BACKGROUND

Under the existing national surveillance system in China for selected infectious diseases, bacterial cultures are performed for only a small percentage of reported cases. We set up a laboratory-based syndromic surveillance system to elucidate bacterial etiologic spectrum and detect infection by rare etiologies (or serogroups) for five core syndromes in the given study area.

METHODS

Patients presenting with one of five core syndromes at nine sentinel hospitals in Guagnxi, China were evaluated using laboratory-based syndrome surveillance to elucidate bacterial etiologies. We collected respiratory and stool specimens, as well as CSF, blood and other related samples for bacterial cultures and pulse field gel electrophoresis (PFGE) assays.

RESULTS

From February 2009 to December 2011, 2,964 patients were enrolled in the study. Etiologies were identified in 320 (10.08%) patients. Streptococcus pneumonia (37 strains, 24.18%), Klebsiella pneumonia (34, 22.22%), Pseudomonas aeruginosa (19, 12.42%) and Haemophilus influenza (18, 11.76%) were the most frequent pathogens for fever and respiratory syndrome, while Salmonella (77, 81.05%) was most often seen in diarrhea syndrome cases. Salmonella paratyphi A (38, 86.36%) occurred in fever and rash syndrome, with Cryptococcus neoformans (20, 35.09%), Streptococcus pneumonia (5, 8.77%), Klebsiella pneumonia (5, 8.77%),streptococcus suis (3, 5.26%) and Neisseria meningitides group B (2, 3.51%) being the most frequently detected in encephalitis-meningitis syndrome. To date no pathogen was isolated from the specimens from fever and hemorrhage patients.

CONCLUSIONS

In addition to common bacterial pathogens, opportunistic pathogens and fungal infections require more attention. Our study contributes to the strengthening of the existing national surveillance system and provides references for other regions that are similar to the study area.