Importance of Legionella pneumophila in the etiology of severe community-acquired pneumonia in Santiago, Chile

Determinant of 30-Day Mortality of Pulmonary Legionellosis: Do Coinfections Matter?

We retrospectively reviewed 64 cases of cancer with pulmonary legionellosis (Legionella pneumophila in 73%). Nearly all patients received Legionella-active antibiotics, yet 30-day mortality was 23%. Independent predictors of 30-day mortality were hyponatremia, bilateral lung involvement, and Sequential Organ Failure Assessment score ≥5. Lung coinfections were common (31%) but did not significantly increase mortality.

Three cases of hospitalized Legionella pneumonia patients successfully treated with lascufloxacin

Legionella pneumonia is one of the major causes of severe pneumonia, in which treatment delay might lead to a poor prognosis. Therefore, as far as possible, early diagnosis and treatment of Legionella pneumonia is essential. Regarding the antimicrobials for Legionella pneumonia, fluoroquinolones, such as levofloxacin, or macrolides, such as azithromycin (AZM), are recommended in Japan and other countries. Lascufloxacin (LSFX), the newest fluoroquinolone developed in Japan, has been in use in daily clinical practice since January 2020. However, there are only few reports of Legionella pneumonia cases treated with LSFX. Here, we report three cases of hospitalized Legionella pneumonia patients that were successfully treated using LSFX. All three patients were admitted to the medical ward on admission, although one patient was subsequently transferred to the ICU for mechanical ventilatory management due to worsening of the pneumonia on day 3. All patients improved and were discharged following LSFX treatment (the patient admitted to the ICU was treated using LSFX + AZM combination therapy) without any severe adverse events. LSFX might be considered to be the first antibiotic choice for Legionella pneumonia, similar to levofloxacin. However, further data regarding the treatment of Legionella pneumonia cases using LSFX are needed to evaluate its efficacy and safety.

Identification rate of Legionella species in non-purulent sputum culture is comparable to that in purulent sputum culture in Legionella pneumonia

Many Legionella pneumonia patients do not produce sputum, and it is unknown whether purulent sputum is required for the identification of Legionella species. This study aimed to evaluate the identification rate of Legionella species based on sputum quality and the factors predictive of Legionella infection. This study included Legionella pneumonia patients at Kurashiki Central Hospital from November 2000 to December 2022. Sputum quality, based on gram staining, was classified as the following: Geckler 1/2, 3/6 and 4/5. Geckler 4/5 was defined as purulent sputum. The sputa of 104 of 124 Legionella pneumonia patients were cultured. Fifty-four patients (51.9%) were identified with Legionella species, most of which were Legionella pneumophila serogroup 1 (81.5%). The identification rates of Legionella species according to sputum quality were 57.1% (16/28) in Geckler 1/2 sputum, 50.0% (34/68) in Geckler 3/6 sputum, and 50.0% (4/8) in Geckler 4/5 sputum, which were not significantly different (P = 0.86). On multivariate analysis, pre-culture treatment with anti-Legionella antimicrobials (odds ratio [OR] 0.26, 95% confidence interval [CI] 0.06-0.91), Pneumonia Severity Index class ≥IV (OR 2.57 [95% CI 1.02-6.71]), and intensive care unit admission (OR 3.08, 95% CI 1.06-10.09) correlated with the ability to identify Legionella species, but sputum quality did not (OR 0.88, 95% CI 0.17-4.41). The identification rate of Legionella species in non-purulent sputum was similar to that in purulent sputum. For the diagnosis of Legionella pneumonia, sputum should be collected before administering anti-Legionella antibiotics and cultured regardless of sputum quality.

A Rare Case of Community-Acquired Pneumonia Only Presenting With Diarrhea, Abdominal Pain, and Fever: A Case Report

Legionnaires' disease is an atypical pneumonia caused by Legionella pneumophila (L. pneumophila) pneumonia that features slow onset, nonproductive cough, fatigue, headache, sore throat, myalgias, and malaise. It can be difficult to diagnose, as it presents with extrapulmonary symptoms, and delay in treatment can be fatal. Here, we present the case of a previously healthy 32-year-old Caucasian male with Legionnaires disease who only presented to the clinic with abdominal pain and diarrhea. The patient did not have any pulmonary symptoms at the initial presentation. This presentation did not fit the diagnostic tools available for Legionnaires' disease, including a validated clinical prediction rule, which ruled out L. pneumophila infection with a sensitivity of 97% and a negative predictive value of 99.4%. Due to the complaint of abdominal pain, a flat/upright abdominal X-ray was ordered, which includes a chest X-ray. Upon analyzing the chest X-ray, a right lower lobe consolidation was identified, prompting an L. pneumophila urinary test to be added to the lab orders. This case represents the difficulties in diagnosing Legionnaires' disease due to the diverse clinical complexities of presentations, which may solely involve abdominal complaints.

Identification of priority pathogens for aetiological diagnosis in adults with community-acquired pneumonia in China: a multicentre prospective study

BACKGROUND

Community-acquired pneumonia (CAP) is a major public health challenge worldwide. However, the aetiological and disease severity-related pathogens associated with CAP in adults in China are not well established based on the detection of both viral and bacterial agents.

METHODS

A multicentre, prospective study was conducted involving 10 hospitals located in nine geographical regions in China from 2014 to 2019. Sputum or bronchoalveolar lavage fluid (BALF) samples were collected from each recruited CAP patient. Multiplex real-time PCR and bacteria culture methods were used to detect respiratory pathogens. The association between detected pathogens and CAP severity was evaluated.

RESULTS

Among the 3,403 recruited eligible patients, 462 (13.58%) had severe CAP, and the in-hospital mortality rate was 1.94% (66/3,403). At least one pathogen was detected in 2,054 (60.36%) patients, with two or more pathogens were co-detected in 725 patients. The ten major pathogens detected were Mycoplasma pneumoniae (11.05%), Haemophilus influenzae (10.67%), Klebsiella pneumoniae (10.43%), influenza A virus (9.49%), human rhinovirus (9.02%), Streptococcus pneumoniae (7.43%), Staphylococcus aureus (4.50%), adenovirus (2.94%), respiratory syncytial viruses (2.35%), and Legionella pneumophila (1.03%), which accounted for 76.06-92.52% of all positive detection results across sampling sites. Klebsiella pneumoniae (p < 0.001) and influenza viruses (p = 0.005) were more frequently detected in older patients, whereas Mycoplasma pneumoniae was more frequently detected in younger patients (p < 0.001). Infections with Klebsiella pneumoniae, Staphylococcus aureus, influenza viruses and respiratory syncytial viruses were risk factors for severe CAP.

CONCLUSIONS

The major respiratory pathogens causing CAP in adults in China were different from those in USA and European countries, which were consistent across different geographical regions over study years. Given the detection rate of pathogens and their association with severe CAP, we propose to include the ten major pathogens as priorities for clinical pathogen screening in China.

Prevalence of atypical pathogens in patients with severe pneumonia: a systematic review and meta-analysis

OBJECTIVES

We aimed to summarise the prevalence of atypical pathogens in patients with severe pneumonia to understand the prevalence of severe pneumonia caused by atypical pathogens, improve clinical decision-making and guide antibiotic use.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase, Web of Science and Cochrane Library were searched through November 2022.

ELIGIBILITY CRITERIA

English language studies enrolled consecutive cases of patients diagnosed with severe pneumonia, with complete aetiological analysis.

DATA EXTRACTION AND SYNTHESIS

We conducted literature retrieval on PubMed, Embase, Web of Science and The Cochrane Library to estimate the prevalence of Chlamydia, Mycoplasma and Legionella in patients with severe pneumonia. After double arcsine transformation of the data, a random-effects model was used for meta-analyses to calculate the pooled prevalence of each pathogen. Meta-regression analysis was also used to explore whether the region, different diagnostic method, study population, pneumonia categories or sample size were potential sources of heterogeneity.

RESULTS

We included 75 eligible studies with 18 379 cases of severe pneumonia. The overall prevalence of atypical pneumonia is 8.1% (95% CI 6.3% to 10.1%) In patients with severe pneumonia, the pooled estimated prevalence of Chlamydia, Mycoplasma and Legionella was 1.8% (95% CI 1.0% to 2.9%), 2.8% (95% CI 1.7% to 4.3%) and 4.0% (95% CI 2.8% to 5.3%), respectively. We noted significant heterogeneity in all pooled assessments. Meta-regression showed that the pneumonia category potentially influenced the prevalence rate of Chlamydia. The mean age and the diagnostic method of pathogens were likely moderators for the prevalence of Mycoplasma and Legionella, and contribute to the heterogeneity of their prevalence.

CONCLUSIONS

In severe pneumonia, atypical pathogens are notable causes, especially Legionella. The diagnostic method, regional difference, sample size and other factors contribute to the heterogeneity of prevalence. The estimated prevalence and relative heterogeneity factors can help with microbiological screening, clinical treatment and future research planning.

PROSPERO REGISTRATION NUMBER

CRD42022373950.

[Legionnaires' disease in Argentina: Evolution of the laboratory diagnostic strategy]

Legionnaires' disease (LD) is severe acute pneumonia that occurs in sporadic or epidemic form, and generally requires hospitalization. The objective of this work was to describe the experience in the LD laboratory diagnostic approach in Argentina during the period 2016-2021. The laboratory analyzed 168 clinical specimens from 93 cases of suspected LD pneumonia. Laboratory tests included the detection of the soluble antigen of Legionella pneumophila serogroup 1 in urine sample, detection of DNA of Legionella spp. in lower respiratory secretions by conventional and commercial molecular methods and isolation in selective medium. LD was confirmed in 12 patients. The urinary antigen allowed the diagnosis for 8 patients. L. pneumophila was isolated from the respiratory material of 6 patients suffering from health care-associated pneumonia, who had been previously diagnosed using the commercial molecular method. Fifty percent of these cases did not show detectable urinary antigen. A single patient did not shows neither detectable antigenuria nor isolation of Legionella from the respiratory sample and was diagnosed as a confirmed case of LD by the detection of DNA of Legionella spp. by PCR directly from the respiratory secretion and the epidemiological link with another case of confirmed LD by culture. Urinary antigen detection is the first-line diagnostic test. However, the incorporation of complementary molecular methods has proved to avoid false negatives and contributed to a better understanding of the true incidence of the disease.

Legionnaires' Disease: Update on Diagnosis and Treatment

Legionellosis is the infection caused by bacteria of the genus Legionella, including a non-pneumonic influenza-like syndrome, and Legionnaires’ disease is a more serious illness characterized by pneumonia. Legionellosis is becoming increasingly important as a public health problem throughout the world; although it is an underreported disease, studies have consistently documented a high incidence. In addition, health costs associated with the disease are high. Diagnosis of Legionnaires’ disease is based mainly on the detection of Legionella pneumophila serogroup 1 antigen in urine. However, there have been advances in detection tests for patients with legionellosis. New methodologies show greater sensitivity and specificity, detect more species and serogroups of Legionella spp., and have the potential for use in epidemiological studies. Testing for Legionella spp. is recommended at hospital admission for severe community-acquired pneumonia, and antibiotics directed against Legionella spp. should be included early as empirical therapy. Inadequate or delayed antibiotic treatment in Legionella pneumonia has been associated with a worse prognosis. Either a fluoroquinolone (levofloxacin or moxifloxacin) or a macrolide (azithromycin preferred) is the recommended first-line therapy for Legionnaires’ disease; however, little information is available regarding adverse events or complications, or about the duration of antibiotic therapy and its association with clinical outcomes. Most published studies evaluating antibiotic treatment for Legionnaires’ disease are observational and consequently susceptible to bias and confounding. Well-designed studies are needed to assess the usefulness of diagnostic tests regarding clinical outcomes, as well as randomized trials comparing fluoroquinolones and macrolides or combination therapy that evaluate outcomes and adverse events.

Accuracy of a score predicting the presence of an atypical pathogen in hospitalized patients with moderately severe community-acquired pneumonia

BACKGROUND

Atypical pathogens (AP), present in some patients with community-acquired pneumonia (CAP), are intrinsically resistant to betalactam drugs, the mainstay of empirical antibiotic treatment. Adding antibiotic coverage for AP increases the risk of adverse effects and antimicrobial selection pressure, while withholding such coverage may worsen the prognosis if an AP is causative. A clinical model predicting the presence of AP would allow targeting atypical coverage for patients most likely to benefit.

METHODS

This is a secondary analysis of a multicentric randomized controlled trial that included 580 adults patients hospitalized for CAP. A predictive score was built using independent predictive factors for AP identified through multivariate analysis. Accuracy of the score was assessed using area under the receiver operating curve (AUROC), sensitivity, and specificity.

RESULTS

Prevalence of AP was 5.3%. Age < 75 years (OR 2.7, 95% CI 1.2-6.2), heart failure (OR 2.6, 95% CI 1.1-6.1), absence of chest pain (OR 3.0, 95% CI 1.1-8.2), natremia < 135 mmol/L (OR 3.0, 95% CI 1.4-6.6) and contracting the disease in autumn (OR 2.7, 95% CI 1.3-5.9) were independently associated with AP. A predictive score using these factors had an AUROC of 0.78 (95% CI 0.71-0.85). A score of 0 or 1 (present in 33% of patients) had 100% sensitivity and 35% specificity.

CONCLUSION

Use of a score built on easily obtained clinical and laboratory data would allow safe withholding of atypical antibiotic coverage in a significant number of patients, with an expected positive impact on bacterial resistance and drug adverse effects.

TRIAL REGISTRATION

NCT00818610.

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

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

Predictors of intensive care unit admission in patients with Legionella pneumonia: role of the time to appropriate antibiotic therapy

Purpose

Legionella spp. pneumonia (LP) is a cause of community-acquired pneumonia (CAP) that requires early intervention. The median mortality rate varies from 4 to 11%, but it is higher in patients admitted to intensive care unit (ICU). The objective of this study is to identify predictors of ICU admission in patients with LP.

Methods

A single-center, retrospective, observational study conducted in an academic tertiary-care hospital in Pisa, Italy. Adult patients with LP consecutively admitted to study center from October 2012 to October 2019.

Results

During the study period, 116 cases of LP were observed. The rate of ICU admission was 20.7% and the overall 30-day mortality rate was 12.1%. Mortality was 4.3% in patients hospitalized in medical wards versus 41.7% in patients transferred to ICU (p < 0.001). The majority of patients (74.1%) received levofloxacin as definitive therapy, followed by macrolides (16.4%), and combination of levofloxacin plus a macrolide (9.5%). In the multivariate analysis, diabetes (OR 8.28, CI 95% 2.11–35.52, p = 0.002), bilateral pneumonia (OR 10.1, CI 95% 2.74–37.27, p = 0.001), and cardiovascular events (OR 10.91, CI 95% 2.83–42.01, p = 0.001), were independently associated with ICU admission, while the receipt of macrolides/levofloxacin therapy within 24 h from admission was protective (OR 0.20, CI 95% 0.05–0.73, p = 0.01). Patients who received a late anti-Legionella antibiotic (> 24 h from admission) underwent urinary antigen test later compared to those who received early active antibiotic therapy (2 [2–4] vs. 1 [1–2] days, p < 0.001).

Conclusions

Admission to ICU carries significantly increased mortality in patients with diagnosis of LP. Initial therapy with an antibiotic active against Legionella (levofloxacin or macrolides) reduces the probability to be transferred to ICU and should be provided in all cases until Legionella etiology is excluded.

Evaluation of a novel urinary antigen test kit for diagnosing Legionella pneumonia

OBJECTIVES

The aim of this study was to evaluate the diagnostic utility of a novel test kit that could theoretically detect all serogroups of Legionella pneumophila for diagnosing Legionella pneumonia, in comparison with existing kits.

METHODS

This study was conducted in 16 hospitals in Japan from April 2016 to December 2018. Three urinary antigen test kits were used: the novel kit (LAC-116), BinaxNOW Legionella (Binax), and Q-line Kyokutou Legionella (Q-line). In addition, sputum culture and nucleic acid detection tests and serum antibody tests were performed where possible. The diagnostic accuracy and correlations of the novel kit with the two existing kits were analyzed.

RESULTS

In total, 56 patients were diagnosed with Legionella pneumonia. The sensitivities of LAC-116, Binax, and Q-line were 79%, 84%, and 71%, respectively. The overall match rate between LAC-116 and Binax was 96.8% and between LAC-116 and Q-line was 96.4%. One patient had L. pneumophila serogroup 2, and only LAC-116 showed a positive result, whereas Binax and Q-line did not.

CONCLUSIONS

The novel Legionella urinary antigen test kit was useful for diagnosing Legionella pneumonia. In addition, it could detect Legionella pneumonia caused by non-L. pneumophila serogroup 1.

Case report: fatal pneumonia caused by new sequence type Legionella pneumophilia serogroup 1

INTRODUCTION

Legionnaires' disease is caused by Legionella bacteria, and commonly manifests as pneumonia and has a high fatality rate.

PATIENT CONCERNS

This case study reports on the fatal incident of a patient, initially diagnosed with pneumonia, and subsequently diagnosed with Legionnaires' disease caused by a new sequence type (ST) of Legionella.

DIAGNOSIS

It is speculated that the patient acquired Legionnaires' disease from a contaminated water source. Legionnaires' disease was diagnosed using the Legionella urinary antigen assay and bacterial cultures of respiratory secretions; Legionella pneumophilia Type 1 was also identified through serological testing. Sequence-based typing of the cultured bacterium revealed it to be a previously unidentified species, and it was named ST2345 new-type.

INTERVENTIONS

In addition to the treatment of Legionnaires' disease, blood samples taken on the second day of admission showed a co-infection of Candida tropicalis, which was treated with anti-fungal treatment. The patient improved after a week, however, on the seventh day of administration lower respiratory secretions showed the growth of Klebsiella pneumonia, indicative of ventilator-associated pneumonia.

OUTCOMES

Despite active treatment, the patient passed away due to multiple organ failure. As this was a fatal case, further research is needed to determine whether the critical condition of this case was related to the virulence of the novel Legionella strain.

CONCLUSION

A key finding of this study is that treatment for suspected Legionnaires' disease must be administered rapidly, as infection with Legionella may give rise to secondary pathogenic infections.

Hyponatremia in Infectious Diseases-A Literature Review

Hyponatremia is one of the most common water-electrolyte imbalances in the human organism. A serum sodium concentration threshold of less than 135 mmol/L is diagnostic for hyponatremia. The disorder is usually secondary to various diseases, including infections. Our review aims to summarize the diagnostic value and impact of hyponatremia on the prognosis, length of the hospitalization, and mortality among patients with active infection. The scientific literature regarding hyponatremia was reviewed using PubMed, ClinicalKey, and Web of Science databases. Studies published between 2011 and 2020 were screened and eligible studies were selected according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement and specific inclusion criteria. The most common infections that were associated with hyponatremia were viral and bacterial infections, including COVID-19 (coronavirus disease 2019). The etiology varied according to the infection site, setting and patient cohort it concerned. In several studies, hyponatremia was associated with prolonged hospitalization, worse outcomes, and higher mortality rates. Hyponatremia can also play a diagnostic role in differentiating pathogens that cause a certain infection type, as it was observed in community-acquired pneumonia. Although many mechanisms leading to hyponatremia have already been described, it is impossible with any certainty to ascribe the etiology of hyponatremia to any of them.

Diabetes-associated infections: development of antimicrobial resistance and possible treatment strategies

Diabetes mellitus is associated with various types of infections notably skin, mucous membrane, soft tissue, urinary tract, respiratory tract and surgical and/or hospital-associated infections. The reason behind this frequent association with infections is an immunocompromised state of diabetic patient because uncontrolled hyperglycemia impairs overall immunity of diabetic patient via involvement of various mechanistic pathways that lead to the diabetic patient as immunocompromised. There are specific microbes that are associated with each type of infection and their presence indicates specific type of infections. For instance, E. coli and Klebsiella are the most common causative pathogens responsible for the development of urinary tract infections. Diabetic-foot infections commonly occur in diabetic patients. In this article, we have mainly focused on the association of diabetes mellitus with various types of bacterial infections and the pattern of resistance against antimicrobial agents that are frequently used for the treatment of diabetes-associated infections. Moreover, we have also summarized the possible treatment strategies against diabetes-associated infections.

Atypical pathogens in hospitalized patients with community-acquired pneumonia: a worldwide perspective

BACKGROUND

Empirical antibiotic coverage for atypical pathogens in community-acquired pneumonia (CAP) has long been debated, mainly because of a lack of epidemiological data. We aimed to assess both testing for atypical pathogens and their prevalence in hospitalized patients with CAP worldwide, especially in relation with disease severity.

METHODS

A secondary analysis of the GLIMP database, an international, multicentre, point-prevalence study of adult patients admitted for CAP in 222 hospitals across 6 continents in 2015, was performed. The study evaluated frequency of testing for atypical pathogens, including L. pneumophila, M. pneumoniae, C. pneumoniae, and their prevalence. Risk factors for testing and prevalence for atypical pathogens were assessed through univariate analysis.

RESULTS

Among 3702 CAP patients 1250 (33.8%) underwent at least one test for atypical pathogens. Testing varies greatly among countries and its frequency was higher in Europe than elsewhere (46.0% vs. 12.7%, respectively, p < 0.0001). Detection of L. pneumophila urinary antigen was the most common test performed worldwide (32.0%). Patients with severe CAP were less likely to be tested for both atypical pathogens considered together (30.5% vs. 35.0%, p = 0.009) and specifically for legionellosis (28.3% vs. 33.5%, p = 0.003) than the rest of the population. Similarly, L. pneumophila testing was lower in ICU patients. At least one atypical pathogen was isolated in 62 patients (4.7%), including M. pneumoniae (26/251 patients, 10.3%), L. pneumophila (30/1186 patients, 2.5%), and C. pneumoniae (8/228 patients, 3.5%). Patients with CAP due to atypical pathogens were significantly younger, showed less cardiovascular, renal, and metabolic comorbidities in comparison to adult patients hospitalized due to non-atypical pathogen CAP.

CONCLUSIONS

Testing for atypical pathogens in patients admitted for CAP in poorly standardized in real life and does not mirror atypical prevalence in different settings. Further evidence on the impact of atypical pathogens, expecially in the low-income countries, is needed to guidelines implementation.

Clinical Utility of Testing for Legionella Pneumonia in Central Texas

RATIONALE

Legionella pneumophila is an uncommon cause of community-acquired pneumonia in the south central region of the United States, and regular testing may not be cost effective in areas of low incidence.

OBJECTIVES

To evaluate the incidence of Legionella in central Texas and to determine the cost effectiveness of Legionella urinary antigen testing.

METHODS

We performed a single-center retrospective cohort study of patients admitted with pneumonia between January 2001 and December 2013. Patients were identified by Binax Legionella urinary antigen and International Classification of Disease, Ninth Revision codes. Demographic characteristics and clinical history of the confirmed Legionella pneumonia cases were obtained by chart review. Descriptive statistics were used to describe patient characteristics.

MEASUREMENTS AND MAIN RESULTS

Over 12 years, 5,807 patients with 11,377 admissions for pneumonia were tested for Legionella urinary antigen. A positive Legionella urinary antigen was found in 17 patients. Cumulative incidence during the study period was 0.23%. Among the Legionella-positive patients, intensive care unit admission and median length of stay were 58.8% and 8.5 days, respectively. Most patients (64.7%) met American Thoracic Society criteria for severe pneumonia. All patients empirically received either a macrolide or fluoroquinolone covering Legionella. There were two in-hospital and three total 90-day deaths in those with a positive urinary antigen. The estimated cost of screening this population with Legionella urinary antigen was $214,438 over 13 years.

CONCLUSIONS

This study reveals the low incidence of Legionella pneumonia in central Texas. Use of guideline-concordant antibiotic treatment provides coverage for Legionella. We speculate that testing in a low-prevalence area would not influence outcomes or be cost effective.

New Insights into Pericarditis: Mechanisms of Injury and Therapeutic Targets

PURPOSE OF REVIEW

This review article aims to provide a contemporary insight into the pathophysiological mechanisms of and therapeutic targets for pericarditis, drawing distinction between autoinflammatory and autoimmune pericarditis.

RECENT FINDINGS

Recent research has focused on the distinction between autoinflammatory and autoimmune pericarditis. In autoinflammatory pericarditis, viruses can activate the sensor molecule of the inflammasome, which results in downstream release of cytokines, such as interleukin-1, that recruit neutrophils and macrophages to the site of injury. Conversely, in autoimmune pericarditis, a type I interferon signature predominates, and pericardial manifestations coincide with the severity of the underlying systemic autoimmune disease. In addition, autoimmune pericarditis can also develop after cardiac injury syndromes. With either type of pericarditis, imaging can help stage the inflammatory state. Prominent pericardial delayed hyperenhancement on magnetic resonance imaging suggests ongoing inflammation whereas calcium on computed tomography suggests a completed inflammatory cascade. In patients with ongoing pericarditis, treatments that converge on the inflammasome, such as colchicine and anakinra, have proved effective in recurrent autoinflammatory pericarditis, though further clinical trials with anakinra are warranted. An improved understanding of the pathophysiological mechanisms of pericarditis helps unravel effective therapeutic targets for this condition.

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.

Characterization of the nasopharyngeal viral microbiome from children with community-acquired pneumonia but negative for Luminex xTAG respiratory viral panel assay detection

In the present study, 50 nasopharyngeal swabs from children with community‐acquired pneumonia (CAP) but negative for 18 common respiratory viruses, as measured by the Luminex xTAG Respiratory Viral Panel Assay, were subjected to multiplex metagenomic analyses using a next‐generation sequencing platform. Taxonomic analysis showed that all sequence reads could be assigned to a specific species. An average of 95.13% were assigned to the Bacteria kingdom, whereas, only 0.72% were potentially virus derived. This snapshot of the respiratory tract virome revealed most viral reads to be respiratory tract related, classified into four known virus families: Paramyxoviridae, Herpesviridae, Anelloviridae, and Polyomaviridae. Importantly, we detected a novel human parainfluenza virus 3 (HPIV 3) strain with a 32‐bp insertion in the haemagglutinin‐neuraminidase (HN) gene that produced a negative result in the Luminex assay, highlighting the strength of virome metagenomic analysis to identify not only novel viruses but also viruses likely to be missed by ordinary clinical tests. Thus, virome metagenomic analysis could become a viable clinical diagnostic method.

Is Legionellosis Present and Important in Colombia? An Analyses of Cases from 2009 to 2013

Infection due to Legionella pneumophila has been not studied in Colombia, although it is present. The observational, retrospective study in which the incidence of legionellosis in Colombia, 2009-2013, was estimated based on data extracted from the personal health records system (Registro Individual de Prestación de Servicios, RIPS) using the ICD-10 codes A48.1 (Legionnaires' disease) and A48.2 (Pontiac Fever). Using official population estimates of the National Administrative Department of Statistics (DANE), crude and adjusted incidence rates were estimated (cases / 100,000 pop). During the period, 206 cases were reported (mean of 41.2 per year) for the cumulated national rate of 0.45 cases / 100,000 pop. The clinical form of legionellosis with the highest incidence rates was the non-pneumonic Legionnaires' disease (0.39 cases / 100,000 pop) with women being the main affected (0.42 cases / 100,000 pop). The territory with the highest incidence rate was Bolivar department (1.94 cases / 100,000 pop), followed by La Guajira (1.7 cases / 100,000 pop). Finally, age groups with the highest morbidity were 0-9.999 years old (1.16 cases / 100,000 pop) and system of identification for social subsidies beneficiaries (SISBEN) category with the highest number of total cases was level one (88 cases). According to these results, we can show that legionellosis in Colombia is more common than it could be thought. Nevertheless, cross-sectional and prospective studies should be conducted in our country in order to improve the knowledge of incidence, prevalence, and burden of disease.

Atypical pathogen infection in community-acquired pneumonia

Community-acquired pneumonia (CAP) is a world wide cause of morbidity and mortality. The etiology of CAP is different between countries and changes over time. With the increasing incidence, atypical pathogens are attracting more and more attention all over the world. In many countries, atypical pathogens are one of the main pathogens of CAP, and even could be the most prevalent etiology in China. Atypical pathogen infections can cause multi-system complications, which leads to a worse prognosis. Although still controversial, empirical antibiotic coverage of atypical pathogens in CAP may improve outcomes, shorten length of hospitalization, reduce mortality and lower total hospitalization costs. The macrolide resistance rate of atypical pathogens, especially Mycoplasma Pneumoniae (M. Pneumoniae) is high, so fluoroquinolones or tetracyclines should be considered as alternative therapy.

Advances in the prevention, management, and treatment of community-acquired pneumonia

Community-acquired pneumonia (CAP) is the infectious disease with the highest number of deaths worldwide. Nevertheless, its importance is often underestimated. Large cohorts of patients with CAP have been established worldwide and improved our knowledge about CAP by far. Therefore, current guidelines are much more evidence-based than ever before. This article discusses recent major studies and concepts on CAP such as the role of biomarkers, appropriate risk stratification to identify patients in need of hospitalisation or intensive care, appropriate empiric antibiotic therapy (including the impact of macrolide combination therapy and antibiotic stewardship), and CAP prevention with novel influenza and pneumococcal vaccines.

Community-acquired pneumonia

Community-acquired pneumonia causes great mortality and morbidity and high costs worldwide. Empirical selection of antibiotic treatment is the cornerstone of management of patients with pneumonia. To reduce the misuse of antibiotics, antibiotic resistance, and side-effects, an empirical, effective, and individualised antibiotic treatment is needed. Follow-up after the start of antibiotic treatment is also important, and management should include early shifts to oral antibiotics, stewardship according to the microbiological results, and short-duration antibiotic treatment that accounts for the clinical stability criteria. New approaches for fast clinical (lung ultrasound) and microbiological (molecular biology) diagnoses are promising. Community-acquired pneumonia is associated with early and late mortality and increased rates of cardiovascular events. Studies are needed that focus on the long-term management of pneumonia.