Comparative study of the clinical presentation of Legionella pneumonia and other community-acquired pneumonias

Effects of corticosteroids in hospitalized patients with Legionella pneumonia: A retrospective cohort study

INTRODUCTION

Legionella pneumophila is an important cause of pneumonia, however there is scant literature assessing the therapeutic benefit of corticosteroids in treatment. We sought to investigate the association between corticosteroid use and in-hospital mortality for patients hospitalized with Legionella pneumonia.

METHODS

Data was collected retrospectively from January 2012 to July 2019 at a 705 bed hospital in New York City. Patients were included if they received a positive Legionella test. Exclusion criteria included age <18, concurrent immunosuppression, and HIV diagnosis. We assessed the relationship between corticosteroid use and in-hospital mortality. Statistical analyses were performed in RStudio.

RESULTS

The study included 160 patients, among which 32 (20%) received steroids. Overall mortality was 7.5% (12.5% among steroid recipients, 6.2% among controls). 25% of patients were admitted to the ICU (37.5% among steroid recipients, 21.9% among controls). Adjusted analysis showed steroid recipients did not have significantly different mortality (aOR = 2.56, p = 0.436). Steroid use was not significantly associated with longer LOS (p = 0.22). Steroid use was significantly associated with hyperglycemia (aOR = 2.91, p = 0.018) and GI bleed (OR = 9.0, p = 0.014).

CONCLUSIONS

We found that in patients hospitalized with Legionella pneumonia, corticosteroid administration was not significantly associated with longer hospitalization or mortality. All findings held true when adjusting for known predictors of pneumonia severity. Corticosteroid use was associated with increased rates of hyperglycemia and GIB requiring blood transfusion. The results of this study are consistent with guidelines recommending against routine use of corticosteroids in CAP.

A Case of Severe, Difficult-to-Diagnose Legionnaires' Disease in a Young Welder

Legionellosis among welders and other metalworkers is a rare but potentially underappreciated occupational hazard. The same mechanisms that predispose welders to severe pneumonia from Streptococcus pneumoniae and Bacillus cereus may similarly predispose them to Legionella pneumophila infection. We present a case of a previously healthy, immunocompetent 31-year-old male welder presenting with three days of shortness of breath, hypoxia, high-grade fever, and blood-tinged sputum. Chest computed tomography (CT) revealed a lobar consolidation of the right middle and lower lobes. Laboratory evaluation showed borderline hyponatremia, hypophosphatemia, and elevated liver enzymes. The patient was ultimately intubated and started on broad-spectrum antibiotics. Multiple respiratory cultures were negative and Legionella urine antigen testing was also negative. Eventually, bronchial Legionella culture was positive for Legionella pneumophila, and a blood next-generation sequencing test also confirmed the diagnosis. He was extubated six days following admission and subsequently discharged.

A Case of Legionnaires' Disease Manifesting as Heat Exhaustion

A 69-year-old male with a history of prior admissions of heat exhaustion presented with non-specific symptoms including fatigue, diarrhea, and dehydration. The workup revealed a positive legionella urine antigen. He was treated with levofloxacin with symptom resolution within 48 hours.

Epidemiology and outcomes of hyponatremia in patients with COVID-19-A territory-wide study in Hong Kong

Background

Hyponatremia is common in COVID-19, but its epidemiology and impact on clinical outcomes in relation to different variants, especially the Omicron variant, requires further clarification.

Methods

This was a territory-wide retrospective study to investigate the epidemiology and outcomes of COVID-19 patients with hyponatremia from January 1, 2020 to March 31, 2022 in Hong Kong. The primary outcome was 30-day mortality of patients with COVID-19 and hyponatremia at presentation. Secondary outcomes included rate of hospitalization, intensive care unit (ICU) hospitalization, overall duration of hospitalization, and duration of ICU hospitalization.

Results

A total of 53,415 COVID-19 patients were included for analysis, of which 14,545 (27.2%) had hyponatremia at presentation. 9813 (67.5%), 2821 (19.4%), and 1911 (13.1%) had mild (130 to <135 mmol/L), moderate (125 to <130 mmol/L), and severe hyponatremia (<125 mmol/L) at presentation respectively. Age, male sex, diabetes, active malignancy, white cell count, serum creatinine, hypoalbuminemia, C-reactive protein, and viral loads were independent predictors for hyponatremia in COVID-19 patients (P < 0.001, for all). Hyponatremic patients had increased 30-day mortality (9.7 vs. 5.7%, P < 0.001), prolonged hospitalization (11.9 ± 15.1 days vs. 11.5 ± 12.1 days, P < 0.001), and more ICU admissions (7.0% vs. 3.3%, P < 0.001). Patients diagnosed during the "fifth wave" Omicron BA.2 outbreak had 2.29-fold risk (95% CI 2.02-2.59, P < 0.001) of presenting with hyponatremia compared to other waves.

Conclusion

Hyponatremia is common among COVID-19 patients, and may serve as a prognostic indicator for unfavorable outcomes and increased healthcare utilization in the evolving COVID-19 outbreak.

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

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

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.

Research Trends and Hotspots of Q Fever Research: A Bibliometric Analysis 1990-2019

Q fever is a worldwide distributed zoonosis caused by Coxiella burnetii, a Gram-negative bacterium. Despite existence of large amount of research data on the developments related to Q fever, no bibliometric analysis of this subject is available to our knowledge. Bibliometric studies are an essential resource to track scholarly trends and research output in a subject. This study is aimed at reporting a bibliometric analysis of publications related to Q fever (2,840 articles published in the period 1990-2019) retrieved from Science Citation Index Expanded, an online database of Clarivate Analytics Web of Science Core Collection. Data was retrieved using keywords “Q fever” or “Coxiella burnetii” in title, abstract, and author keywords to describe important research indicators such as the kind and language of articles, the most important publications, research journals and categories, authors, institutions, and the countries having the most significant contribution to this subject. Finally, the emerging areas in field of diagnosis, host range, and clinical presentation were identified. Word cluster analysis of research related to Q fever revealed that major focus of research has been on zoonosis, seroprevalence, laboratory diagnosis (mainly using ELISA and PCR), clinical manifestations (abortion and endocarditis), vectors (ticks), and hosts (sheep, goat, and cattle). This bibliometric study is intended to visualize the existing research landscape and future trends in Q fever to assist in future knowledge exchange and research collaborations.

National survey of physicians in Japan regarding their use of diagnostic tests for legionellosis

INTRODUCTION

Bacterial culture remains the gold standard for the diagnosis of legionellosis. However, past reports indicate that most physicians use the urinary antigen test (UAT) alone. Combining it with other tests is important, especially in patients with negative UAT results. The aim of this study was to investigate the current situation of legionellosis diagnostics and clarify the issues that need to be addressed.

METHODS

Between March 1, 2021 and April 30, 2021, a questionnaire survey was conducted in an anonymous manner among physicians working in Japan. Questionnaires were generated on a website and asked questions in a multiple-choice format.

RESULTS

Valid responses were received from 309 physicians during the study period. Most (92.9%) physicians reported using UAT as the initial test for patients suspected of having legionellosis, and <10% reported using other tests (e.g., culture, nucleic acid amplification test [NAAT], Gimenez staining, and serum antibody titer measurement [ATM]). When the initial test result was negative, 63% of physicians reported not conducting additional tests. Even when they chose to run additional tests, at most 27.8%, 23.6%, 12.3%, and 10.4% of all physicians used NAAT, culture, Gimenez staining, and serum ATM, respectively. The major reasons for not using tests other than UAT were "unavailability in the medical facility," "long turn-around time," and "difficult to collect sputum."

CONCLUSIONS

The present survey revealed that most physicians in Japan used UAT alone for diagnosing legionellosis. Eliminating barriers to creating a reasonable environment and edification of physicians are needed to improve the current situation.

Legionella Pneumonia in the ICU: A Tertiary Care Center Experience Over 10 Years

OBJECTIVES:

Few studies have reported the complications and outcomes of patients with Legionella pneumonia requiring ICU admission. The objective of our study is to report the clinical course, complications, and 30-day mortality of patients with Legionella pneumonia admitted to the critical care units at our medical center over a 10-year period.

DESIGN:

Retrospective observational study.

SETTING:

Tertiary care teaching hospital.

PATIENTS:

All adult (≥ 18 yr old) patients with Legionella pneumonia admitted to the ICUs from January 1, 2010, to December 31, 2019.

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

A total of 88 patients with Legionella pneumonia were admitted to ICUs over the 10-year period. The majority of infections (n = 80; 90.9%) were community acquired. The median (interquartile range) age of patients was 60 years (51.5–71.0 yr); 58 (66%) were male, and 41 (46.6%) identified their race as Black. The median (interquartile range) Sequential Organ Failure Assessment score at ICU admission was 6 (3–9). The distribution of infections showed seasonal dominance with most cases (86%) occurring in the summer to early fall (May to October). Invasive mechanical ventilation was required in 62 patients (70.5%), septic shock developed in 57 patients (64.8%), and acute respiratory distress syndrome developed in 42 patients (47.7%). A majority of patients developed acute kidney injury (n = 69; 78.4%), with 15 (21.7%) receiving only intermittent hemodialysis and 15 (21.7%) requiring continuous renal replacement therapy. Ten patients required venovenous extracorporeal membrane oxygenation support; eight (80%) survived and were successfully decannulated. Overall 30-day mortality was 26.1% (n = 23). Advanced age, higher Sequential Organ Failure Assessment score at admission, and not receiving Legionella-specific antimicrobial therapy within 24 hours of hospital admission were predictors of 30-day mortality.

CONCLUSIONS:

Patients with Legionella pneumonia may require ICU admission and major organ support. Legionella-targeted antibiotics should be included in the empiric regimen for any patient with severe pneumonia. Outcomes of extracorporeal membrane oxygenation therapy in this population are encouraging.

Clinical and computed tomographic features of Legionella pneumonia with negative urine antigen test results

BACKGROUND

Legionella spp. can cause severe pneumonia and most Legionella pneumonia (LP) cases are diagnosed using the urine antigen test (UAT). However, diagnosis of LP with negative UAT results (LPNUAT) is challenging. We investigated the clinical and radiological features of LPNUAT.

METHODS

We retrospectively collected LP cases with positive UAT (LPPUAT) and cases of suspected LP with negative UAT that were examined by Legionella culture between July 2014 and March 2020. We investigated the clinical and CT findings for LP that showed negative UAT results and was diagnosed by culture and compared these findings with those for other pneumonias suspicious for LP with negative results in UAT and Legionella culture (OPSLP).

RESULTS

Eight LPNUAT, 20 LPPUAT, and 19 OPSLP cases were included in this study. There were no significant differences in the clinical and CT findings between LPPUAT and LPNUAT when examined by UAT. In LPNUAT, dyspnea, renal dysfunction, liver dysfunction, and bilateral lesions were more commonly observed and inflammatory changes and the number of affected lobes were significantly higher when examined by culture than when examined by UAT. Comparison to OPSLP, LPNUAT did not show such differences, but rather showed disturbances in consciousness, hyponatremia and rhabdomyolysis. Furthermore, lobar consolidation was observed more frequently and bronchial wall thickening and centrilobular nodules were observed less frequently in LPNUAT.

CONCLUSIONS

LP characteristics such as disturbance of consciousness, hyponatremia, rhabdomyolysis, lobar consolidation, and less bronchial wall thickening and centrilobular nodule contribute to the diagnosis of LP in patients with negative UAT results.

Potent T-cell mediated immune response against Legionella pneumophila in mice following vaccination with detoxified lipopolysaccharide non-covalently combined with recombinant flagellin A and peptidoglycan-associated lipoprotein

BACKGROUND

Legionella pneumophila is a Gram-negative intracellular bacterium and the cause of an atypical pneumonia in humans - legionnaire's disease. Immunological assessment of bacterial antigens clarifies the way that host may develop protection against the pathogen. Lipopolysaccharide (LPS) is the main antigen of Gram-negative bacteria but is less studied because of its carbohydrate nature. Here, we immunized mice with detoxified LPS in combination with immunogenic proteins and looked into the result of bacterial challenge.

METHODS

LPS of L. pneumophila was extracted by hot phenol-water method. Purified LPS was detoxified by sodium hydroxide alkaline procedure. BALB/c mice were immunized mainly with non-covalent combination of detoxified LPS (dLPS) and either of recombinant FlaA or PAL separately. Afterwards, specific serum IgG was assessed by ELISA. Mice were challenged intravenously with sublethal dose of L. pneumpphila then splenocytes were cultured. Cytokine responses of splenocytes were analyzed by ELISA.

RESULTS

Polysaccharide antigen did not elicit significant serum IgG. Combination of the dLPS with recombinant FlaA and PAL led to risen IgG and its subclasses (IgG1, IgG2a and IgG2b) against polysaccharide. Mice immunized with combination of the dLPS and recombinant proteins showed significant elevation of cytokine responses in splenocyte culture after being challenged with L. pneumophila.

CONCLUSIONS

Our results suggest that combination of polysaccharide antigen derived from Legionella LPS may confer raised cell-mediated responses against the pathogen when combined with Th-1 stimulating protein antigens. Although not covalently bond, Legionella detoxified LPS combination with recombinant FlaA and PAL effectively elicited Th-1 type cytokines and humoral responses against L. pneumophila in BALB/c mice.

Fatal Fulminant Legionnaires' Disease in a Patient on Maintenance Hemodialysis

We herein report a case of fulminant Legionnaires' disease with autopsy findings in a patient on maintenance hemodialysis (HD). Chronic kidney disease is a strong risk factor for Legionnaires' disease, although there have been only a few reports in HD patients. Because most patients on HD are anuric, the use of rapid assay kits to detect antigens in urine samples for the diagnosis of Legionnaires' disease is not always feasible. We suggest the use of clinical predictive tools or the loop-mediated isothermal amplification (LAMP) method, which can be applied for anuric patients, such as those on HD, with pneumonia.

Where is Chlamydophila pneumoniae pneumonia?

BACKGROUND

Molecular diagnostic methods have recently gained widespread use, and consequently, the importance of viral pathogens in community-acquired pneumonia (CAP) has undergone re-evaluation. Under these circumstances, the role of Chlamydophila pneumoniae as a pathogen that causes CAP also needs to be reviewed.

METHODS

We reviewed articles that contained data on the frequency of identification of C. pneumoniae pneumonia as a causative pathogen for CAP. The articles were identified by performing a search in PubMed with the keywords "community-acquired pneumonia" and "pathogen".

RESULTS

Sixty-three articles were identified. The reviewed articles demonstrated that the rates of identification of C. pneumoniae as the causative pathogen for CAP were significantly lower in assessments based on polymerase chain reaction (PCR) methods than in those based on serological methods. In some studies, it was possible to compare both serological and PCR methods directly using the same set of samples.

CONCLUSIONS

The use of PCR methods, including multiplex PCR assays, has revealed that C. pneumoniae may play a limited role as a pathogen for CAP.

Established association of legionella with rhabdomyolysis and renal failure: A review of the literature

Legionella causes 2–15% of community acquired pneumonia cases that require hospitalization and it is the second most common cause of serious pneumonia that needs admission in an intensive care unit. Since the first published case in 1980, there are a further 22 published case reports on the direct correlation between rhabdomyolysis, renal failure and Legionnaires' disease. All but two patients survived with antibiotics and dialysis. Clinicians should be cognisant of this established triad and correlation of Legionnaires’ disease, renal failure and rhabdomyolysis, as failure to do so and initiate treatment early has proven to increase mortality significantly in affected patients.

Legionella Pneumonia Following the Heavy Rain Event of July 2018 in Japan

We herein report the case of a 62-year-old man diagnosed with Legionella pneumonia while engaged in recovery work in a flooded area after the Heavy Rain Event of July 2018 in Japan. The patient was intubated and maintained on mechanical ventilation and continuous hemodiafiltration. He was also administered antimicrobial therapy with ciprofloxacin and azithromycin. After 53 days in the hospital, he was discharged. It is important to recognize the risk of Legionella infection and to take measures to prevent it during recovery work that involves exposure to water and soil after a flood disaster.

Pneumococcal and Legionella Urinary Antigen Tests in Community-acquired Pneumonia: Prospective Evaluation of Indications for Testing

BACKGROUND

Adult, community-acquired pneumonia (CAP) guidelines from the Infectious Diseases Society of America (IDSA) and American Thoracic Society (ATS) include indications for urinary antigen tests (UATs) for Streptococcus pneumoniae (SP) and Legionella pneumophila (LP). These recommendations were based on expert opinions and have not been rigorously evaluated.

METHODS

We used data from a multicenter, prospective, surveillance study of adults hospitalized with CAP to evaluate the sensitivity and specificity of the IDSA/ATS UAT indications for identifying patients who test positive. SP and LP UATs were completed on all included patients. Separate analyses were completed for SP and LP, using 2-by-2 contingency tables, comparing the IDSA/ATS indications (UAT recommended vs not recommended) and UAT results (positive vs negative). Additionally, logistic regression was used to evaluate the association of each individual criterion in the IDSA/ATS indications with positive UAT results.

RESULTS

Among 1941 patients, UATs were positive for SP in 81 (4.2%) and for LP in 32 (1.6%). IDSA/ATS indications had 61% sensitivity (95% confidence interval [CI] 49-71%) and 39% specificity (95% CI 37-41%) for SP, and 63% sensitivity (95% CI 44-79%) and 35% specificity (95% CI 33-37%) for LP. No clinical characteristics were strongly associated with positive SP UATs, while features associated with positive LP UATs were hyponatremia, fever, diarrhea, and recent travel.

CONCLUSIONS

Recommended indications for SP and LP urinary antigen testing in the IDSA/ATS CAP guidelines have poor sensitivity and specificity for identifying patients with positive tests; future CAP guidelines should consider other strategies for determining which patients should undergo urinary antigen testing.

Extreme Rhabdomyolysis, Acute Renal Failure, and Protracted Ileus in a Case of Legionella Pneumonia

A 53-year-old man developed a Legionella pneumophila pneumonia complicated by rhabdomyolysis, acute kidney injury, and protracted ileus. Risk factors were smoking and chronic alcoholism, but the patient had no history of previous abdominal surgery. Hemodialysis was required for a period of 5 weeks with a full renal recovery. Pneumonia required respiratory support but for a limited period of 6 days. The protracted course of the ileus led to explorative laparotomy despite negative computed tomography findings. No cause of mechanical obstruction was found at surgery and common etiologies of intestinal obstruction were excluded. Parenteral nutrition was needed for a total of 4 weeks, before recovery of intestinal motility. This case illustrates the apparent discrepancy between the pulmonary symptoms and the extrapulmonary manifestations that could be seen as a consequence of an exaggerated immune response.

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.

Legionella pneumonia due to non-Legionella pneumophila serogroup 1: usefulness of the six-point scoring system

Background

Because of a limited number of reports, we aimed to investigate the clinical characteristics of patients with Legionella pneumonia due to non-Legionella pneumophila serogroup 1 and the diagnostic usefulness of the six-point scoring system for such patients compared with patients with pneumonia caused by L. pneumophila serogroup 1.

Methods

We retrospectively analysed patients diagnosed with Legionella pneumonia due to non-L. pneumophila serogroup 1 between March 2001 and June 2016. We examined the clinical characteristics, including symptoms, laboratory findings, radiologic findings, pneumonia severity, initial treatment and prognosis. We also calculated scores using the six-point scoring system in these patients. Furthermore, we compared the clinical characteristics and six-point scores between non-L. pneumophila serogroup 1 patients and L. pneumophila serogroup 1 patients among hospitalized community-acquired pneumonia patients enrolled prospectively between October 2010 and July 2016.

Results

Eleven patients had pneumonia due to non-L. pneumophila serogroup 1; their median age was 66 years and 8 patients (72.7%) were male. The most common pathogen was L. pneumophila serogroup 3 (6/11), followed by L. pneumophila serogroup 9 (3/11), L. pneumophila serogroup 6 (1/11) and L. longbeachae (1/11). Non-specific symptoms, such as fever and cough, were common. Six patients (54.5%) had liver enzyme elevation, but no patient developed hyponatraemia at <130 mEq/L. Nine patients (81.8%) showed lobar pneumonia and 7 patients (63.6%) manifested with consolidation and ground-glass opacity. Patients with mild to moderate severity comprised 10 (90.9%) by CURB-65 and 5 (45.5%) by the Pneumonia Severity Index. Of all patients, 4 were admitted to the intensive care unit and 3 died despite appropriate empiric therapy. The clinical characteristics were not significantly different between non-L. pneumophila serogroup 1 patients and L. pneumophila serogroup 1 patients (n = 23). At a cut-off value of ≥ 2 points, the sensitivity of the six-point scoring system was 54.5% (6/11) for non-L. pneumophila serogroup 1 patients and 95.7% (22/23) for L. pneumophila serogroup 1 patients.

Conclusions

Cases of non-L. pneumophila serogroup 1 pneumonia varied in severity from mild to severe and the clinical characteristics were often non-specific. The six-point scoring system was not useful in predicting such Legionella pneumonia cases.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0559-3) contains supplementary material, which is available to authorized users.

Management of community-acquired pneumonia in immunocompetent adults: updated Swedish guidelines 2017

Based on expert group work, Swedish recommendations for the management of community-acquired pneumonia in adults are here updated. The management of sepsis-induced hypotension is addressed in detail, including monitoring and parenteral therapy. The importance of respiratory support in cases of acute respiratory failure is emphasized. Treatment with high-flow oxygen and non-invasive ventilation is recommended. The use of statins or steroids in general therapy is not found to be fully supported by evidence. In the management of pleural infection, new data show favourable effects of tissue plasminogen activator and deoxyribonuclease installation. Detailed recommendations for the vaccination of risk groups are afforded.

Atypical bacterial pneumonia in the HIV-infected population

Human immunodeficiency virus (HIV)-infected individuals are more susceptible to respiratory tract infections by other infectious agents (viruses, bacteria, parasites, and fungi) as their disease progresses to acquired immunodeficiency syndrome. Despite effective antiretroviral therapy, bacterial pneumonia (the most frequently occurring HIV-associated pulmonary illness) remains a common cause of morbidity and mortality in the HIV-infected population. Over the last few decades, studies have looked at the role of atypical bacterial pneumonia (i.e. pneumonia that causes an atypical clinical presentation or responds differently to typical therapeutics) in association with HIV infection. Due to the lack of available diagnostic strategies, the lack of consideration, and the declining immunity of the patient, HIV co-infections with atypical bacteria are currently believed to be underreported. Thus, following an extensive database search, this review aimed to highlight the current knowledge and gaps regarding atypical bacterial pneumonia in HIV. The authors discuss the prevalence of Chlamydophila pneumoniae, Mycoplasma pneumoniae, Coxiella burnetii, Legionella species and others in the HIV-infected population as well as their clinical presentation, methods of detection, and treatment. Further studies looking at the role of these microbes in association with HIV are required. Increased knowledge of these atypical bacteria will lead to a more rapid diagnosis of these infections, resulting in an improved quality of life for the HIV-infected population.

The typical presentation of an atypical pathogen during an outbreak of Legionnaires' disease in Vila Franca de Xira, Portugal, 2014

BACKGROUND

An outbreak of Legionella pneumophila serogroup 1, with 403 cases was identified on the 7th November 2014 in Vila Franca de Xira, Portugal. Outbreak source was the wet cooling system of a local factory. Hospital Pulido Valente was one of the hospitals receiving patients with Legionnaires' disease (LD).

METHODS

We describe the clinical findings and diagnostic methods used among the 43 confirmed or probable cases admitted to our department.

RESULTS

60.5% were male, mean age was 56.1±13.5 years and tobacco smoking was the most frequent risk factor (76.7%). All patients had fever, 62.8% ≥39.5°C, 72.1% had chills and myalgia/arthralgia and 62.8% had dry cough. Extra pulmonary symptoms were frequent: confusion and headache occurred in 34.9% and gastrointestinal symptoms in 20.9%. High C-Reactive Protein (55.8% ≥30mg/dL) and hyponatremia (62.8%) were the laboratorial abnormalities most commonly found. Hypoxemia occurred in 55.8% and hypocapnia in 93%. Urinary Antigen Test (UAT) was positive in 83.7% of the cases.

CONCLUSIONS

Although not specific, a combination of risk factors, symptoms and laboratory findings can be highly suggestive of LD, even in an outbreak. This should prompt diagnosis confirmation. Routine use of UAT in less severe cases of community acquired pneumonia might contribute to earlier diagnosis.

Atypical Pneumonia: Updates on Legionella, Chlamydophila, and Mycoplasma Pneumonia

Community-acquired pneumonia (CAP) has multiple causes and is associated with illness that requires admission to the hospital and mortality. The causes of atypical CAP include Legionella species, Chlamydophila, and Mycoplasma. Atypical CAP remains a diagnostic challenge and, therefore, likely is undertreated. This article reviews the advancements in the evaluation and treatment of patients and discusses current conflicts and controversies of atypical CAP.

Legionnaires' disease caused by Legionella longbeachae: Clinical features and outcomes of 107 cases from an endemic area

BACKGROUND AND OBJECTIVE

Legionella longbeachae is a predominant cause of Legionnaires' disease in some parts of the world, particularly in Australasia. Clinical reports of L. longbeachae infection are limited to case reports or small case series, and culture-confirmed cases.

METHODS

We reviewed the clinical characteristics and outcomes of L. longbeachae pneumonia in a large case series from Christchurch, New Zealand during a 4-year period when both PCR and cultures were used as routine diagnostic tools for Legionnaires' disease. Cases of Legionella pneumophila pneumonia were reviewed for comparison.

RESULTS

A total of 107 cases of L. longbeachae infection were identified by PCR and/or culture. The median age was 65 years (range 25-90 years), 63% were male, and most became unwell during spring or summer. Presenting clinical features were similar to those reported for community-acquired pneumonia, with headache, myalgia and diarrhoea being common. Elevated C-reactive protein, hyponatraemia and abnormal liver function tests were also common. History of productive cough, involvement of both lungs, and high bacterial load were independently associated with culture of Legionella from lower respiratory samples. One quarter required intensive care unit admission, and 5% died. Among patients given antimicrobial therapy before admission, those given agents without anti-Legionella activity were more likely to be admitted to the intensive care unit. Limited comparisons were made with the 19 L. pneumophila cases over the same time period.

CONCLUSION

Characteristics of L. longbeachae pneumonia are broadly similar to those reported for community-acquired pneumonia from a variety of other populations, except for the spring/summer seasonality.

Multiplex real-time PCR assay for Legionella species

Legionella pneumophila serogroup 1 (sg1) accounts for the majority of infections in humans, but other Legionella species are also associated with human disease. In this study, a new SYBR Green I-based multiplex real-time PCR assay in a single reaction was developed to allow the rapid detection and differentiation of Legionella species by targeting specific gene sequences. Candidate target genes were selected, and primer sets were designed by referring to comparative genomic hybridization data of Legionella species. The Legionella species-specific groES primer set successfully detected all 30 Legionella strains tested. The xcpX and rfbA primers specifically detected L. pneumophila sg1-15 and L. pneumophila sg1, respectively. In addition, this assay was validated by testing clinical samples and isolates. In conclusion, this novel multiplex real-time PCR assay might be a useful diagnostic tool for the rapid detection and differentiation of Legionella species in both clinical and epidemiological studies.

Rash, disseminated intravascular coagulation and legionella: Episode 10 and a rewind into the past

Legionella pneumophila is the most common cause of legionellosis and is one of the organisms causing atypical pneumonia. We report the presentation of disseminated intravascular coagulation (DIC) and skin rash in a single case of severe Legionella pneumonia. The unique clinical presentation of a diffuse rash diagnosed as purpura fulminans and the unpredictable variations encountered during the diagnostic work-up of the case make this write-up crucial. This article synthesizes all reported cases of L. pneumonia associated with cutaneous manifestations as well as cases presenting with DIC. Furthermore, this manuscript illustrates the correlation between cutaneous and coagulopathic manifestations, and morbidity and mortality from L. pneumonia.

Presence and Chromosomal Subtyping ofLegionellaSpecies in Potable Water Systems in 20 Hospitals of Catalonia, Spain

Objective:

To investigate the presence and clonal distribution ofLegionellaspecies in the water supply of 20 hospitals in Catalonia, Spain.

Setting:

20 hospitals in Catalonia, an area of 32,000 km2, located in northeast Spain.

Methods:

Environmental cultures of 186 points of potable water supply and 10 cooling towers were performed for the presence ofLegionellaspecies. Following filtration and acid treatment, the samples were seeded in selective MWY (modified Wadowsky Yee)-buffered charcoal yeast extract-a agar. All isolates obtained were characterized microbiologically and genotyped bySfilpulsed-field gel electrophoresis (PFGE).

Results:

73 of 196 water samples, representing 17 of the 20 hospitals included in the study, were positive forLegionella pneumophila(serogroups 1, 2-14, or both). The degree of contamination ranged from 200 to 74,250 colony-forming units/L. Twenty-five chromosomal DNA subtypes were detected by PFGE. A single DNA subtype was identified in 10 hospitals, 2 DNA subtypes were observed in 6 hospitals, and 1 hospital exhibited 3 different DNA subtypes. Each hospital had its ownLegionellaDNA subtype, which was not shared with any other hospitals.

Conclusions:

Legionellawas present in the water of most of the hospitals studied; each such hospital had a unique, dominant chromosomal DNA subtype. The verification of several genomic DNA restriction profiles in such a small geographic area demonstrates the great genetic diversity ofLegionellain the aquatic environment.

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

BACKGROUND

In US and European literature, Legionella pneumophila is reported as an important etiologic agent of severe community-acquired pneumonia (CAP), but in Chile this information is lacking. The aim of this study was to determine the incidence and identify predictors of severe CAP caused by L pneumophila in Santiago, Chile.

METHODS

A multicenter, prospective clinical study lasting 18 months was conducted; it included all adult patients with severe CAP admitted to the ICUs of four hospitals in Santiago. We excluded patients who were immunocompromised, had been hospitalized in the previous 4 weeks, or presented with another disease during their hospitalization. All data for the diagnosis of severe CAP were registered, and urinary antigens for L pneumophila serogroup 1 were determined.

RESULTS

A total of 104 patients with severe CAP were included (mean ± SD age, 58.3 ± 19.3 years; men, 64.4%; APACHE (Acute Physiology and Chronic Health Evaluation) II score, 16.7 ± 6.3; Sepsis-related Organ Failure Assessment score, 6.1 ± 3.2; Pitt Bacteremia Score, 3.4 ± 2.5; Pao2/Fio2, 170.8 ± 87.1). An etiologic agent was identified in 62 patients (59.6%), with the most frequent being Streptococcus pneumoniae (27 patients [26%]) and L pneumophila (nine patients [8.6%]). Logistic regression analysis showed that a plasma sodium level of ≤ 130 mEq/L was an independent predictor for L pneumophila severe CAP (OR, 11.3; 95% CI, 2.5-50.5; P = .002). Global mortality was 26% and 33% for L pneumophila. The Pitt bacteremia score and pneumonia score index were the best predictors of mortality.

CONCLUSIONS

We found that in Santiago, L pneumophila was second to S pneumoniae as the etiologic agent of severe CAP. Severe hyponatremia at admission appears to be an indicator for L pneumophila etiology in severe CAP.

[A case of Legionnaires' infection with meningeal irritation and abnormal cerebrospinal fluid]

A 60-year-old man was admitted to our hospital because of fever and mental status change. Neurological examination showed meningeal irritation and frontal sign. Cerebrospinal fluid (CSF) examination showed mild pleocytosis and elevated protein. Laboratory findings showed hyponatremia, elevated liver enzymes and creatine phosphokinase, and positive Legionella pneumophila antigen in urine. The chest computed tomographic scans showed consolidation in the left lower lobe lung. We diagnosed Legionnaires' pneumonia and started treatment with levofloxacin. Legionella pneumophila was isolated from culture of the bronchoalveolar lavage fluid, but Legionella culture and polymerase chain reaction in CSF were negative. We hypothesize that Legionella pneumophila could produce nerological symptoms by immune-mediated mechanism associated with elevated IgG index. The neurologist should recognize the presence of the meningo-encephalitis associated with Legionnaires' pneumonia lacking remarkable pulmonary symptoms.

Current clinical management of Legionnaires’ disease

Legionella pneumophila is increasingly recognized as a cause of both sporadic and epidemic community-acquired pneumonia. Clinical manifestations of Legionnaires' disease are not specific and current diagnostic scores are of limited use. Urinary antigen detection is an effective test for rapid diagnosis of infection caused by L. pneumophila serogroup 1. Improved outcomes regarding the time to defervescence, development of complications and length of stay, have been recently observed for patients treated with levofloxacin monotherapy. Current case-fatality rates for hospitalized patients with community-acquired Legionella pneumonia are lower than those traditionally reported for this infection. Effective preventive strategies are needed.

Community-acquired pneumonia among smokers

Recent studies have left absolutely no doubt that tobacco increases susceptibility to bacterial lung infection, even in passive smokers. This relationship also shows a dose-response effect, since the risk reduces spectacularly 10 years after giving up smoking, returning to the level of non-smokers. Streptococcus pneumoniae is the causative microorganism responsible for community-acquired pneumonia (CAP) most frequently associated with smoking, particularly in invasive pneumococcal disease and septic shock. It is not clear how it acts on the progress of pneumonia, but there is evidence to suggest that the prognosis for pneumococcal pneumonia is worse. In CAP caused by Legionella pneumophila, it has also been observed that smoking is the most important risk factor, with the risk rising 121% for each pack of cigarettes smoked a day. Tobacco use may also favor diseases that are also known risk factors for CAP, such as periodontal disease and upper respiratory viral infections. By way of prevention, while giving up smoking should always be proposed, the use of the pneumococcal vaccine is also recommended, regardless of the presence of other comorbidities.

Legionnaires’ Disease and Use of Tumor Necrosis Factor-Αlpha Inhibitors: A Forthcoming Problem?

Aim: To establish a review in the current literature and to analyze the relation Legionnaires’ disease – TNF-α inhibitors, in order to estimate the real indications for such connection.Material and Methods: The electronic data for PubMed and Google Scholar have been searched, according to the vocabulary: legionellosis, epidemiology, outbreak, diagnosis, pathogenesis, therapy, TNF-α inhibitors, indications, side effects, risk of infection. The obtained studies have been selected in English, according to the relevance by the topic.Results: Selected papers, consisted of ten studies and eight case reports, yielded 35 cases of Legionnaires' disease associated with the use of TNF- α inhibitor treatment.Discussion: There is a prevailing conclusion for increased risk of serious infections while using TNF-α inhibitors and also a deficiency of studies for an association of Legionnaires’ disease with the use of TNF-α inhibitors. Sub-diagnosing and no-existence of screening before the anti-TNF-α therapy blur the factual profile for the researched relation. The possibility for latent infection has not been sufficiently researched.Conclusion: There are indications that Legionnaires’ disease in the therapy with TNF-α inhibitors is indeed a forthcoming problem. Additional target researches are required in order to establish the position of Legionnaires’ disease in the mosaic of anti - TNF-α therapy.

[Multidisciplinary guidelines for the management of community-acquired pneumonia]

Community-acquired pneumonia (CAP) is an infectious respiratory disease with an incidence that ranges from 3 to 8 cases per 1,000 inhabitants per year. This incidence increases with age and comorbidities. Forty per cent of CAP patients require hospitalization and around 10% of these patients are admitted in an Intensive Care Unit (ICU). Several studies have suggested that the implementation of clinical guidelines has a positive impact in the outcome of patients including mortality and length of stay. The more recent and used guidelines are those from Infectious Diseases Society of America/American Thoracic Society, published in 2007, the 2009 from the British Thoracic Society, and that from the European Respiratory Society/European Society of Clinical Microbiology and Infectious Diseases, published in 2010. In Spain, the most recently released guideline is the Sociedad Española de Neumología y Cirugía Torácica-2011 guideline. The present guidelines GNAC are designed to be used by the majority of health-care professionals that can participate in the care of CAP patients including diagnosis, decision of hospital and ICU admission, treatment and prevention. The Centro Cochrane Iberoamericano (CCIB) has participated in summarizing the previous guidelines and in the bibliography search. For each one of the following sections the panel of experts has developed a table with recommendations classified according to its evidence, strength and practical applicability using the Grading of Recommendations of Assessment Development and Evaluations (GRADE) system: 1. Epidemiology, microbiological etiology and antibiotic resistances.2. Clinical and microbiological diagnosis.3. Prognostic scales and decision of hospital admission.4. ICU admission criteria. 5. Empirical and definitive antibiotic treatment.6. Treatment failure. 7. Prevention.

Legionnaires’ Disease

Infection with Legionella spp. is an important cause of serious community- and hospital-acquired pneumonia, occurring sporadically and in outbreaks. Outbreaks of Legionnaires' disease have recently received considerable media attention, and some factors indicate that the problem will increase in future. Infection with Legionella spp. ranks among the three most common causes of severe pneumonia in the community setting, and is isolated in 1-40% of cases of hospital-acquired pneumonia. Underdiagnosis and underreporting are high. Only 2-10% of estimated cases are reported. Detection of a single case should not be considered an isolated sporadic event, but rather indicative of unrecognized cases. There are no clinical features unique to Legionnaires' disease; however, suspicion should be raised by epidemiologic information commensurate with the diagnosis and the presence of headache, confusion, hyponatremia, elevated creatine kinase and/or severe pneumonia. An arterial oxygen partial pressure <60mm Hg on presentation and progression of pulmonary infiltrates despite appropriate antibacterial therapy should always alert clinicians to this cause.Macrolides, fluoroquinolones and rifampin (rifampicin) are the most widely used drugs in treatment. Fluoroquinolones or azithromycin are the treatment of choice in immunosuppressed patients and those with severe pneumonia. Incorporation of the legionella urinary antigen test in emergency departments in hospitals and progressive improvement in this test will, in the near future, permit appropriate diagnosis and treatment of this frequent, sometimes severe, illness.

Swedish guidelines on the management of community-acquired pneumonia in immunocompetent adults--Swedish Society of Infectious Diseases 2012

This document presents the 2012 evidence based guidelines of the Swedish Society of Infectious Diseases for the in- hospital management of adult immunocompetent patients with community-acquired pneumonia (CAP). The prognostic score 'CRB-65' is recommended for the initial assessment of all CAP patients, and should be regarded as an aid for decision-making concerning the level of care required, microbiological investigation, and antibiotic treatment. Due to the favourable antibiotic resistance situation in Sweden, an initial narrow-spectrum antibiotic treatment primarily directed at Streptococcus pneumoniae is recommended in most situations. The recommended treatment for patients with severe CAP (CRB-65 score 2) is penicillin G in most situations. In critically ill patients (CRB-65 score 3-4), combination therapy with cefotaxime/macrolide or penicillin G/fluoroquinolone is recommended. A thorough microbiological investigation should be undertaken in all patients, including blood cultures, respiratory tract sampling, and urine antigens, with the addition of extensive sampling for more uncommon respiratory pathogens in the case of severe disease. Recommended measures for the prevention of CAP include vaccination for influenza and pneumococci, as well as smoking cessation.

Distinctive features between community-acquired pneumonia (CAP) due to Chlamydophila psittaci and CAP due to Legionella pneumophila admitted to the intensive care unit (ICU)

The spectrum of community-acquired pneumonia (CAP) due to Chlamydophila psittaci ranges from mild, self-limited CAP, to acute respiratory failure. We performed a retrospective study of 13 consecutive patients with CAP due to C. psittaci and 51 patients with legionellosis admitted in one intensive care unit (ICU) (1993-2011). As compared to patients with legionellosis, patients with psittacosis were younger (median age 48 [38-59] vs. 60 [50-71] years, p = 0.007), less frequently smokers (38 vs. 79 %, p < 0.001), with less chronic disease (15 vs. 57 %, p = 0.02), and longer duration of symptoms before admission (median 6 [5-13] vs. 5 [3-7] days, p = 0.038). They presented with lower Simplified Acute Physiology Score II (median 28 [19-38] vs. 39 [28-46], p = 0.04) and less extensive infiltrates on chest X-rays (median 2 [1-3] vs. 3 [3-4] lobes, p = 0.007). Bird exposure was mentioned in 100 % of psittacosis cases, as compared to 5.9 % of legionellosis cases (p < 0.0001). Extrapulmonary manifestations, biological features, and mortality (15.4 vs. 21.6 %, p = 0.62) were similar in both groups. In conclusion, severe psittacosis shares many features with severe legionellosis, including extrapulmonary manifestations, biological features, and outcome. Psittacosis is an important differential diagnosis for legionellosis, especially in cases of bird exposure, younger age, and more limited disease progression over the initial few days.

Liver cirrhosis as a predisposing condition for Legionnaires' disease: a report of four laboratory-confirmed cases from China

Here, we describe four cases of laboratory-confirmed Legionella infection. Case 1 was a culture-confirmed case of Legionella infection in a patient with liver cirrhosis. Following this, three other liver cirrhosis cases (cases 2-4) were diagnosed with Legionella infection as confirmed by quantitative real-time PCR. The cause of the pneumonia was determined as Legionella pneumophila by positive direct fluorescence assay and isolation of the causative agent. The infections were successfully treated by administering appropriate antibiotics. These cases highlight the importance of considering Legionella as a cause of pneumonia in patients with liver disease and lung infections. The strain of L. pneumophila isolated from Case 1 was characterized as being closely related to strain Philadelphila-1 (ATCC 33152(T)), which is the type strain of the species, belonging to serogroup 1 and sequence type 36 (ST36), and is known to be distributed worldwide. To our knowledge, this is the first report of Legionella infection on the Chinese mainland for a decade and highlights the need to raise awareness of diagnostic methods for Legionnaires' disease in China and the requirement for further epidemiological surveillance strategies to monitor this disease.

Epidemiological investigation of a legionellosis outbreak in a Slovenian nursing home, August 2010

BACKGROUND

August 2010 marked the beginning of the largest outbreak of legionellosis in a Slovenian nursing home. This article presents our experiences with the outbreak investigation.

METHODS

In order to collect the necessary patient epidemiological data, we used individual epidemiological questionnaires. Samples were available from 15 patients and were subject to laboratory investigation. Urine and sputum samples were difficult to obtain due to the underlying diseases of the patients. Serological diagnostics constituted an important part of the epidemiological investigation. Sixty-four environmental samples were taken to identify the sources of infection. By genotyping, we assessed the affinity of the allelic profile of Legionella pneumophila serogroup 1 in environmental samples and in patient samples.

RESULTS

Legionnaires' disease was diagnosed in 10 patients based on a combination of various tests. Legionella pneumophila serogroup 1, Legionella pneumophila serogroups 2-14, and Legionella sp., in concentrations of < 10 to 61,000 CFU/l, were isolated from 51 out of 64 environmental samples. The source of the outbreak was confirmed by genotyping the isolates from patients and the isolates from the water supply system. The 2 isolates had identical allelic profiles corresponding to that of L. pneumophila serogroup 1 allelic profile 2,3,9,10,2,1,6, designated sequence type 23 (according to the European Working Group for Legionella Infections).

CONCLUSION

We describe a Legionella pneumophila serogroup 1 outbreak in a Slovenian nursing home. The source of infection was demonstrated using sequence-based typing. Water flow disturbances were determined as the most probable cause of Legionella growth. Overall, the risk of a Legionella outbreak is underestimated in Slovenia.