Community-acquired Legionella pneumonia: new insights from the German competence network for community acquired pneumonia

Evaluation of the bioNexia Legionella Test, Including Impact of Incubation Time Extension, for Detection of Legionella pneumophila Serogroup 1 Antigen in Urine

In this study, we compared the bioNexia test (bioMérieux, Marcy-l'Étoile, France), a new immunochromatographic assay for the detection of Legionella pneumophila serogroup 1 in urine, with the BinaxNOW urinary antigen test (Alere, Waltham, Massachusetts, USA). After 15 min of incubation (in accordance with the manufacturers' instructions), the sensitivities and specificities were, respectively, 76.5% and 97.2% for the bioNexia test and 87.1% and 100% for the BinaxNOW test. After a prolonged incubation time of 60 min, the sensitivities and specificities increased to, respectively, 89.4% and 97.2% for the bioNexia test and 91.8% and 100% for the BinaxNOW test. When the tests were read after 15 min, the concentration of discrepant urine samples increased the sensitivities to 94.1% for both tests. In conclusion, we found that although the bioNexia test showed lower sensitivity for the detection of L. pneumophila antigen in nonconcentrated urine compared to the BinaxNOW test, a prolonged incubation time as well as the use of concentrated samples showed comparable sensitivities for both tests.

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.

Prognostic scores and biomarkers for pediatric community-acquired pneumonia: how far have we come?

This article aimed to review the current prognostic and diagnostic tools used for community-acquired pneumonia (CAP) and highlight those potentially applicable in children with CAP. Several scoring systems have been developed to predict CAP mortality risk and serve as guides for admission into the intensive care unit. Over the years, clinicians have adopted these tools for improving site-of-care decisions because of high mortality rates in the extremes of age. The major scoring systems designed for geriatric patients include the Pneumonia Severity Index and the confusion, uremia, respiratory rate, blood pressure, age >65 years (CURB-65) rule, as well as better predictors of intensive care unit admission, such as the systolic blood pressure, multilobar chest radiography involvement, albumin level, respiratory rate, tachycardia, confusion, oxygenation and arterial pH (SMART-COP) score, the Infectious Diseases Society of America/American Thoracic Society guidelines, the criteria developed by España et al as well as the systolic blood pressure, oxygenation, age and respiratory rate (SOAR) criteria. Only the modified predisposition, insult, response and organ dysfunction (PIRO) score has so far been applied to children with CAP. Because none of the tools is without its limitations, there has been a paradigm shift to incorporate biomarkers because they are reliable diagnostic tools and good predictors of disease severity and outcome, irrespective of age group. Despite the initial preponderance of reports on their utility in geriatric CAP, much progress has now been made in demonstrating their usefulness in pediatric CAP.

Existence and control of Legionella bacteria in building water systems: A review

Legionellae are waterborne bacteria which are capable of causing potentially fatal Legionnaires' disease (LD), as well as Pontiac Fever. Public concern about Legionella exploded following the 1976 outbreak at the American Legion conference in Philadelphia, where 221 attendees contracted pneumonia and 34 died. Since that time, a variety of different control methods and strategies have been developed and implemented in an effort to eradicate Legionella from building water systems. Despite these efforts, the incidence of LD has been steadily increasing in the U.S. for more than a decade. Public health and occupational hygiene professionals have maintained an active debate regarding best practices for management and control of Legionella. Professional opinion remains divided with respect to the relative merits of performing routine sampling for Legionella, vs. the passive, reactive approach that has been largely embraced by public health officials and facility owners. Given the potential risks and ramifications associated with waiting to assess systems for Legionella until after disease has been identified and confirmed, a proactive approach of periodic testing for Legionella, along with proper water treatment, is the best approach to avoiding large-scale disease outbreaks.

Rapid diagnostic test for respiratory infections

Acute respiratory infections are the second cause of morbidity and mortality in children and adults worldwide, being viruses, bacteria and fungi involved in their aetiology. The rapid diagnosis allows for a better clinical management of the patient, for adopting public health measures and for controlling possible outbreaks. The main etiologic agents can be diagnosed within the first hours after the onset of symptoms with antigen detection techniques, primarily immunochromatography. Results are obtained in 15–30 min, with 70–90% sensitivity and >95% specificity for the diagnosis of Streptococcus pneumoniae and Legionella pneumophila serogroup O1 infections from urine, Streptococcus pyogenes from throat swabs and respiratory syncytial virus from nasopharyngeal aspirates. Worse results are obtained for influenza viruses and Pneumocystis jirovecii with these techniques; however, other easy-to-perform molecular techniques are available for the rapid diagnosis of these microorganisms. In general, these techniques should not be used for monitoring the outcome or response to treatment.

[CAPNETZ. The competence network for community-acquired pneumonia (CAP)]

CAPNETZ is a medical competence network for community-acquired pneumonia (CAP), which was funded by the German Ministry for Education and Research. It has accomplished seminal work on pneumonia over the last 15 years. A unique infrastructure was established which has so far allowed us to recruit and analyze more than 11,000 patients. The CAPNETZ cohort is the largest cohort worldwide and the results obtained relate to all relevant aspects of CAP management (epidemiology, risk stratification via biomarkers or clinical scores, pathogen spectrum, pathogen resistance, antibiotic management, prevention and health care research). Results were published in more than 150 journals and informed the preparation and update of the national S3-guideline. CAPNETZ was also the foundation for further networks like the Pneumonia Research Network on Genetic Resistance and Susceptibility for the Evolution of Severe Sepsis) (PROGRESS), the Systems Medicine of Community Acquired Pneumonia Network (CAPSyS) and SFB-TR84 (Sonderforschungsbereich - Transregio 84). The main recipients (Charité Berlin, University Clinic Ulm and the Hannover Medical School) founded the CAPNETZ foundation and transferred all data and materials rights to this foundation. Moreover, the ministry granted the CAPNETZ foundation the status of being eligible to apply for research proposals and receive research funds. Since 2013 the CAPNETZ foundation has been an associated member of the German Center for Lung Research (DZL). Thus, a solid foundation has been set up for CAPNETZ to continue its success story.

[Rapid diagnostic test for respiratory infections]

Acute respiratory infections are the second cause of morbidity and mortality in children and adults worldwide, being viruses, bacteria and fungi involved in their etiology. The rapid diagnosis allows for a better clinical management of the patient, for adopting public health measures and for controlling possible outbreaks. The main etiologic agents can be diagnosed within the first hours after the onset of symptoms with antigen detection techniques, primarily immunochromatography. Results are obtained in 15-30minutes, with 70-90% sensitivity and >95% specificity for the diagnosis of Streptococcus pneumoniae and Legionella pneumophila serogroup O1 infections from urine, Streptococcus pyogenes from throat swabs and respiratory syncytial virus from nasopharyngeal aspirates. Worse results are obtained for influenza viruses and Pneumocystis jirovecii with these techniques; however, other easy-to-perform molecular techniques are available for the rapid diagnosis of these microorganisms. In general, these techniques should not be used for monitoring the outcome or response to treatment.

Prevalence of Atypical Pathogens in Patients With Cough and Community-Acquired Pneumonia: A Meta-Analysis

PURPOSE

Community-acquired pneumonia (CAP), acute cough, bronchitis, and lower respiratory tract infections (LRTI) are often caused by infections with viruses or Streptococcus pneumoniae. The prevalence of atypical pathogens Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, and Bordetella pertussis among patients with these illnesses in the ambulatory setting has not been previously summarized. We set out to derive prevalence information from the existing literature.

METHODS

We performed a systematic review of MEDLINE for prospective, consecutive-series studies reporting the prevalence of M pneumoniae, C pneumoniae, L pneumophila and/or B pertussis in outpatients with cough, acute bronchitis, LRTI, or CAP. Articles were independently reviewed by 2 authors for inclusion and abstraction of data; discrepancies were resolved by consensus discussion. A meta-analysis was performed on each pathogen to calculate the pooled prevalence estimates using a random effects model of raw proportions.

RESULTS

Fifty studies met our inclusion criteria. While calculated heterogeneity was high, most studies reported prevalence for each pathogen within a fairly narrow range. In patients with CAP, the overall prevalences of M pneumoniae and C pneumoniae were 10.1% (95% CI, 7.1%-13.1%) and 3.5% (95% CI, 2.2%-4.9%), respectively. Consistent with previous reports, M pneumoniae prevalence peaked in roughly 6-year intervals. Overall prevalence of L pneumophila was 2.7% (95% CI, 2.0%-3.4%), but the organism was rare in children, with only 1 case in 1,765. In patients with prolonged cough in primary care, the prevalence of B pertussis was 12.4% (95% CI, 4.9%-19.8%), although it was higher in studies that included only children (17.6%; 95% CI, 3.4%-31.8%).

CONCLUSIONS

Atypical bacterial pathogens are relatively common causes of lower respiratory diseases, including cough, bronchitis, and CAP. Where surveillance data were available, we found higher prevalences in studies where all patients are tested for these pathogens. It is likely that these conditions are underreported, underdiagnosed, and undertreated in current clinical practice.

Disease Burden of 32 Infectious Diseases in the Netherlands, 2007-2011

BACKGROUND

Infectious disease burden estimates provided by a composite health measure give a balanced view of the true impact of a disease on a population, allowing the relative impact of diseases that differ in severity and mortality to be monitored over time. This article presents the first national disease burden estimates for a comprehensive set of 32 infectious diseases in the Netherlands.

METHODS AND FINDINGS

The average annual disease burden was computed for the period 2007-2011 for selected infectious diseases in the Netherlands using the disability-adjusted life years (DALY) measure. The pathogen- and incidence-based approach was adopted to quantify the burden due to both morbidity and premature mortality associated with all short and long-term consequences of infection. Natural history models, disease progression probabilities, disability weights, and other parameters were adapted from previous research. Annual incidence was obtained from statutory notification and other surveillance systems, which was corrected for under-ascertainment and under-reporting. The highest average annual disease burden was estimated for invasive pneumococcal disease (9444 DALYs/year; 95% uncertainty interval [UI]: 8911-9961) and influenza (8670 DALYs/year; 95% UI: 8468-8874), which represents 16% and 15% of the total burden of all 32 diseases, respectively. The remaining 30 diseases ranked by number of DALYs/year from high to low were: HIV infection, legionellosis, toxoplasmosis, chlamydia, campylobacteriosis, pertussis, tuberculosis, hepatitis C infection, Q fever, norovirus infection, salmonellosis, gonorrhoea, invasive meningococcal disease, hepatitis B infection, invasive Haemophilus influenzae infection, shigellosis, listeriosis, giardiasis, hepatitis A infection, infection with STEC O157, measles, cryptosporidiosis, syphilis, rabies, variant Creutzfeldt-Jakob disease, tetanus, mumps, rubella, diphtheria, and poliomyelitis. The very low burden for the latter five diseases can be attributed to the National Immunisation Programme. The average disease burden per individual varied from 0.2 (95% UI: 0.1-0.4) DALYs per 100 infections for giardiasis, to 5081 and 3581 (95% UI: 3540-3611) DALYs per 100 infections for rabies and variant Creutzfeldt-Jakob disease, respectively.

CONCLUSIONS

For guiding and supporting public health policy decisions regarding the prioritisation of interventions and preventive measures, estimates of disease burden and the comparison of burden between diseases can be informative. Although the collection of disease-specific parameters and estimation of incidence is a process subject to continuous improvement, the current study established a baseline for assessing the impact of future public health initiatives.

Rapid investigation of cases and clusters of Legionnaires' disease in England and Wales using direct molecular typing

Legionella pneumophila is the leading cause of Legionnaires' disease, a severe pneumonia that can occur as sporadic cases or point-source outbreaks affecting multiple patients. The infection is acquired by inhalation of aerosols from contaminated water systems. In order to identify the probable source and prevent further cases, clinical and environmental isolates are compared using phenotypic and genotypic methods. Typically up to 10 days are required to isolate L. pneumophila prior to the application of standard typing protocols. A rapid protocol using a real-time PCR specific for L. pneumophila and serogroup 1, combined with nested direct molecular typing, was adopted by Public Health England in 2012 to reduce reporting time for preliminary typing results. This rapid protocol was first used to investigate an outbreak that occurred in July/August 2012 and due to the positive feedback from that investigation, it was subsequently applied to other incidents in England and Wales where faster typing results would have aided incident investigation. We present here results from seven incidents that occurred between July 2012 and June 2015 where the use of this rapid approach provided preliminary characterization of the infecting strain in an average 1.58 days (SD 1.01) after sample receipt in contrast to 9.53 days (SD 3.73) when standard protocols were applied.

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.

Legionellosis in Transplantation

Legionella species are emerging opportunistic pathogens in hematopoietic stem cell and solid organ transplant recipients, associated with significant morbidity and mortality. The clinical and radiological features of Legionella infections can mimic other opportunistic pathogens in these profoundly immunocompromised patients. Diagnosis in transplant patients is challenging as non-pneumophila Legionella infections, for which these patients are at risk, cannot be identified using the urinary antigen test. Changes in management of transplant recipients and changes in Legionella epidemiology suggest that the number of transplant patients potentially exposed to Legionella spp. may be on the rise. Yet, evidence-based, transplant-specific guidelines for managing and preventing Legionella infections are not currently available. In this article, we review the epidemiology, clinical features, diagnostic challenges, treatment options, and preventive strategies of Legionella infections in these high-risk patient populations.

Microbiological diagnosis and molecular typing of Legionella strains during an outbreak of legionellosis in Southern Germany

An explosive outbreak of Legionnaires' disease with 64 reported cases occurred in Ulm/Neu-Ulm in the South of Germany in December 2009/January 2010 caused by Legionella (L.) pneumophila serogroup 1, monoclonal (mAb) subtype Knoxville, sequence type (ST) 62. Here we present the clinical microbiological results from 51 patients who were diagnosed at the University hospital of Ulm, the results of the environmental investigations and of molecular typing of patients and environmental strains. All 50 patients from whom urine specimens were available were positive for L. pneumophila antigen when an enzyme-linked immunosorbent assay (EIA) was used following concentration of those urine samples that tested initially negative. The sensitivity of the BinaxNow rapid immunographic assay (ICA), after 15 min reading and after 60 min reading were 70% and 84%, respectively. Direct typing confirmed the monoclonal subtype Knoxville in 5 out of 8 concentrated urine samples. Real time PCR testing of respiratory tract specimens for L. pneumophila was positive in 15 out of 25 (60%) patients. Direct nested sequence based typing (nSBT) in some of these samples allowed partial confirmation of ST62. L. pneumophila serogroup 1, monoclonal subtype Knoxville ST62, defined as the epidemic strain was isolated from 8 out of 31 outbreak patients (26%) and from one cooling tower confirming it as the most likely source of the outbreak. While rapid detection of Legionella antigenuria was crucial for the recognition and management of the outbreak, culture and molecular typing of the strains from patients and environmental specimens was the clue for the rapid identification of the source of infection.

Legionnaires' disease

Since first identified in early 1977, bacteria of the genus Legionella are recognised as a common cause of community-acquired pneumonia and a rare cause of hospital-acquired pneumonia. Legionella bacteria multisystem manifestations mainly affect susceptible patients as a result of age, underlying debilitating conditions, or immunosuppression. Water is the major natural reservoir for Legionella, and the pathogen is found in many different natural and artificial aquatic environments such as cooling towers or water systems in buildings, including hospitals. The term given to the severe pneumonia and systemic infection caused by Legionella bacteria is Legionnaires' disease. Over time, the prevalence of legionellosis or Legionnaires' disease has risen, which might indicate a greater awareness and reporting of the disease. Advances in microbiology have led to a better understanding of the ecological niches and pathogenesis of the condition. Legionnaires' disease is not always suspected because of its non-specific symptoms, and the diagnostic tests routinely available do not offer the desired sensitivity. However, effective antibiotics are available. Disease notification systems provide the basis for initiating investigations and limiting the scale and recurrence of outbreaks. This report reviews our current understanding of this disease.

Creating a customized intracellular niche: subversion of host cell signaling by Legionella type IV secretion system effectors

The Gram-negative facultative intracellular pathogen Legionella pneumophila infects a wide range of different protozoa in the environment and also human alveolar macrophages upon inhalation of contaminated aerosols. Inside its hosts, it creates a defined and unique compartment, termed the Legionella-containing vacuole (LCV), for survival and replication. To establish the LCV, L. pneumophila uses its Dot/Icm type IV secretion system (T4SS) to translocate more than 300 effector proteins into the host cell. Although it has become apparent in the past years that these effectors subvert a multitude of cellular processes and allow Legionella to take control of host cell vesicle trafficking, transcription, and translation, the exact function of the vast majority of effectors still remains unknown. This is partly due to high functional redundancy among the effectors, which renders conventional genetic approaches to elucidate their role ineffective. Here, we review the current knowledge about Legionella T4SS effectors, highlight open questions, and discuss new methods that promise to facilitate the characterization of T4SS effector functions in the future.

Environmental surveillance and molecular epidemiology of waterborne pathogen Legionella pneumophila in health-care facilities of Northeastern Greece: a 4-year survey

A 4-year proactive environmental surveillance of Legionella spp. in the water distribution and cooling systems of five health-care facilities was carried out as part of the strategy for the prevention of hospital-acquired Legionnaires' disease in Northeastern Greece. Legionella spp. were detected in 71 out of 458 collected samples. The majority of strains belonged to Legionella pneumophila serogroups 2-15 (75.0%), while all L. pneumophila serogroup 1 strains (23.6%) were isolated from a single hospital. The highest percentage of positive samples was found in distal sites (19.4%), while no Legionella strains were detected in cooling systems. Each hospital was colonized at least once with L. pneumophila, while remedial actions resulted in significant reduction of Legionella concentration. The molecular epidemiology of environmental L. pneumophila strains was also investigated using random amplified polymorphic DNA (RAPD) and multi-gene sequence-based analysis. Based on RAPD patterns, L. pneumophila serogroups 2-15 and serogroup 1 strains were classified into 24 and 9 operational taxonomic units (OTUs), respectively. Sequencing of housekeeping and diversifying pressure-related genes recommended by European Working Group for Legionella Infections (EWGLI) revealed not only a high intraspecies variability but also the circulation and persistence of one specific genotyping profile in the majority of hospitals. This study highlights the necessity for diachronic surveillance of Legionella in health-care facilities by adopting both cultural and molecular methods.

Aetiology and risk factors of community-acquired pneumonia in hospitalized patients in Norway

BACKGROUND AND AIMS

In Norway, data on the aetiology of community-acquired pneumonia (CAP) in hospitalized patients are limited. The aims of this study were to investigate the bacterial aetiology of CAP in hospitalized patients in Norway, risk factors for CAP and possible differences in risk factors between patients with Legionnaire's disease and pneumonia because of other causes.

METHODS

Adult patients with radiologically confirmed CAP admitted to hospital were eligible for the study. Routine aerobic and Legionella culture of sputum, blood culture, urinary antigen test for Legionella pneumophila and Streptococcus pneumoniae, polymerase chain reaction detection of Chlamydophila pneumoniae, Mycoplasma pneumoniae and Bordetella pertussis from throat specimens, and serology for L. pneumophila serogroup 1-6 were performed. A questionnaire, which included demographic and clinical data, risk factors and treatment, was completed.

RESULTS

We included 374 patients through a 20-month study period in 2007-2008. The aetiological agent was detected in 37% of cases. S. pneumoniae (20%) was the most prevalent agent, followed by Haemophilus influenzae (6%) and Legionella spp. (6%). Eight Legionella cases were diagnosed by urinary antigen test, of which four also had positive serology. In addition, 13 Legionella cases were diagnosed by serology. The degree of comorbidity was high. An increased risk of hospital-diagnosed Legionella pneumonia was found among patients with a diagnosis of chronic congestive heart failure.

CONCLUSION

Our results indicate that S. pneumoniae is the most common bacterial cause of pneumonia in hospitalized patients, and the prevalence of Legionella pneumonia is probably higher in Norway than recognized previously.

Characterization of the extent of a large outbreak of Legionnaires' disease by serological assays

BACKGROUND

In May 2005, a long-distance outbreak of Legionnaires' disease (LD) caused by Legionella pneumophila serogroup 1 occurred in south-east Norway. The initial outbreak investigation without serology identified 56 laboratory-confirmed LD cases of whom 10 died. However, 116 patients with community-acquired pneumonia might belong to the outbreak based on epidemiological investigations, but acute laboratory tests other than serology were negative or not performed. To assess the true extent of the outbreak, we evaluated two serological assays in order to reclassify the 116 patients with indeterminate case status.

METHODS

Two polyvalent antibody tests, a serogroup 1-6 immunofluorescence assay (IFA) and a serogroup 1-7 enzyme-linked immunosorbent assay (ELISA) were used. They were evaluated with cases defined as culture- or urinary antigen positive LD patients (n=40) and non-cases defined as confirmed non-LD patients (n=39) and healthy control subjects (n=62). The 116 patients, who were negative in culture, polymerase chain reaction and/or urinary antigen tests, were analysed by the same serological assays. Antibodies to the outbreak strain were determined by immunoblotting.

RESULTS

In the evaluation study, the sensitivity and specificity of a ≥4-fold IFA titre change was 38% and 100%, respectively, with corresponding values of 30% and 99% for seroconversion in ELISA. A single high positive IFA titre yielded sensitivity and specificity of 73% and 97%, respectively, with corresponding values of 68% and 96% for a single high immunoglobulin (Ig) G and/or IgM in ELISA. Based on this evaluation, the following serological testing identified 47 more LD cases, and the outbreak thus comprised 103 cases with a case fatality rate of 10%. About the same proportion (70%) of the urinary antigen positive and negative LD cases had antibodies to the serogroup-specific lipopolysaccharide of the outbreak strain. In addition to the 103 LD cases, Legionella infection could not be verified or excluded in 32 patients based on epidemiology and/or lack of microbiological sampling.

CONCLUSIONS

The acute-phase tests (culture, polymerase chain reaction, and urinary antigen) identified less than 55% of the 103 patients in this outbreak. Serological testing thus remains an important supplement for diagnosis of LD and for determination of outbreak cases.

Pancreatic involvement in Legionella pneumonia

Legionella-associated pancreatitis has been rarely reported. Since this condition is very rarely suspected and investigated in patients with Legionella pneumonia, its incidence is probably underestimated. Here we report a case of Legionella pneumonia-associated pancreatitis and review the relevant related literature.

Current and emerging Legionella diagnostics for laboratory and outbreak investigations

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

Legionella pneumophila cases in a community hospital: A 12-month retrospective review

Background:

Legionella pneumonia has long been recognized as an important cause of community-acquired pneumonia associated with significant morbidity and mortality; however, the description of the incidence of this disease is restricted to sporadic cases in the literature. With the advent of an inexpensive and rapid urine antigen test, routine testing has become more common. We report findings of a retrospective review of 266 patients who were admitted with a clinical diagnosis of community-acquired pneumonia over a 12-month period and were tested for Legionella pneumophila serogroup 1, reporting the prevalence and determinants of Legionella infection.

Methods:

Chart reviews of 266 patients admitted for community-acquired pneumonia and who underwent urine antigen testing for Legionella pneumophila during a 1-year time period were conducted, looking at demographic information as well as clinical and laboratory presentation, reporting on the prevalence and determinants of urine antigen positivity using multivariate logistic regression analysis.

Results:

Legionella pneumophila serogroup 1 was found in 2.3% of cases of community-acquired pneumonia. We also found that altered mental status, diarrhea, history of lung disease, and alcohol intake were significantly associated with pneumonia associated with Legionella. The presence of these four factors had a low sensitivity in predicting Legionella infection (33%); however, they had a positive predictive value of 98%, with a specificity of 100. All the Legionella-infected patients in our study required admission to the intensive care unit, and one of them developed Guillain–Barré syndrome, which to our knowledge represents the only reported case of this syndrome related to Legionella infection in an adult in the English scientific literature.

Conclusion:

Legionella pneumophila serogroup 1 is a common cause of sporadic cases of community-acquired pneumonia associated with a high morbidity and protean manifestations. Clinical features have a poor sensitivity in identifying cases, and routine urine antigen testing in patients with suggestive clinical symptoms appears to be a rational approach in the evaluation of community-acquired pneumonia.

Ruling out Legionella in community-acquired pneumonia

BACKGROUND

Assessing the likelihood for Legionella sp. in community-acquired pneumonia is important because of differences in treatment regimens. Currently used antigen tests and culture have limited sensitivity with important time delays, making empirical broad-spectrum coverage necessary. Therefore, a score with 6 variables recently has been proposed. We sought to validate these parameters in an independent cohort.

METHODS

We analyzed adult patients with community-acquired pneumonia from a large multinational database (Community Acquired Pneumonia Organization) who were treated between 2001 and 2012 with more than 4 of the 6 prespecified clinical variables available. Association and discrimination were assessed using logistic regression analysis and area under the curve (AUC).

RESULTS

Of 1939 included patients, the infectious cause was known in 594 (28.9%), including Streptococcus pneumoniae in 264 (13.6%) and Legionella sp. in 37 (1.9%). The proposed clinical predictors fever, cough, hyponatremia, lactate dehydrogenase, C-reactive protein, and platelet count were all associated or tended to be associated with Legionella cause. A logistic regression analysis including all these predictors showed excellent discrimination with an AUC of 0.91 (95% confidence interval, 0.87-0.94). The original dichotomized score showed good discrimination (AUC, 0.73; 95% confidence interval, 0.65-0.81) and a high negative predictive value of 99% for patients with less than 2 parameters present.

CONCLUSIONS

With the use of a large independent patient sample from an international database, this analysis validates previously proposed clinical variables to accurately rule out Legionella sp., which may help to optimize initial empiric therapy.

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.

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.

Incidence and Prognostic Factors for Legionnaires' Disease in Denmark 1993–2006

Objectives. To describe the incidence of Legionnaires’ disease and factors affecting survival in Denmark from 1993 to 2006. Methods. Retrospective register study using data on episodes of Legionnaires’ disease from notification forms and the National Reference Laboratory, and information on comorbidity from national registers on discharge diagnoses and mortality. Results. The average annual incidence of laboratory confirmed cases was 1.5 per 100000 people. The 30-day case fatality was 19%, ranging from 7% in travellers to 37% in hospital-acquired cases. Patients older than 60 years and patients with underlying disease were more likely-to die, as were patients infected with L. pneumophila serogroup 6. The lowest mortality was seen for L. pneumophila serogroup 1. Conclusion. Increased awareness of the disease, better diagnostics, and appropriate testing and treatment strategies are needed to improve survival. In particular, we focus on the relevance of diagnostic methods, such as polymerase chain reaction (PCR), that detect other serogroups than the urinary antigen tests used that will only reliably detect antigen from L. pneumophila serogroup 1. PCR is faster and more sensitive than culture.

Molecular diagnostics and the public health management of legionellosis

In 2009-2010, we investigated four legionella cases notified over an 8-month period in two adjacent villages in South East England. Molecular techniques enabled us to conclude that three of the cases had distinct infections. The absence of an adequate respiratory sample in one case necessitated epidemiological investigations to exclude a potential common environmental source of further infections. One of the cases had spent a part of their incubation period in a country in South East Asia. DNA-sequence-based typing of their isolate showed it to be of the Legionella pneumophila serogroup 1 (LP1) DNA-sequence type (ST) 481. Intriguingly, the only other two ST 481 isolates in the European Working Group for Legionella Infections database were among Dutch travellers to the same country in 2003 and 2006. This case makes clear the value of molecular diagnostics and the importance of obtaining adequate clinical specimens. The potential future uses for typing data are discussed.

Microbial contamination of dental unit waterlines in dental practices in Hesse, Germany: A cross-sectional study

The quality of water from dental units is of considerable importance since patients and dental staff are regularly exposed to water and aerosols generated from the dental unit. This study analyzed the microbial quality of water obtained for periodical monitoring from 56 dental units in different dental practices in Hesse. Contamination by Legionella spp., Pseudomonas aeruginosa, and increased total colony counts were detected in 27.8%, 3.5%, and 17% of samples. Legionella pneumophila serogroup 1 accounted for 28% of Legionella isolates. The Legionella concentration was >100 cfu/100 ml in 84% of contaminated samples. Samples collected from an instrument channel were more frequently contaminated by Legionella than those from cup filler (41.7% vs. 18.6%, p = 0.02). After release of these results, decontamination measures were performed in units that had revealed unsatisfactory results. The outcome of the intervention was followed-up by microbiological analysis. At follow-up, 65.2% and 72.7% of waterlines that had previously been contaminated by Legionella or had shown increased total colony counts were free of contamination. Our results show a high rate of contamination of water from dental units in dental practices in Hesse. They highlight the risk of exposure for patients and personnel and the need for effective strategies to reduce microbial contamination.

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

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

[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.

Use, location, and timeliness of clinical microbiology testing in Georgia for select infectious diseases

OBJECTIVE

Although clinical microbiology testing facilitates both public health surveillance of infectious diseases and patient care, research on testing patterns is scant. We surveyed hospital laboratories in Georgia to assess their diagnostic testing practices.

METHODS

Using e-mail, all directors of hospital laboratories in Georgia were invited to participate. The survey focused on timing and location of diagnostic testing in 2006 for 6 reportable diseases: giardiasis, legionellosis, meningococcal disease, pertussis, Rocky Mountain spotted fever, and West Nile virus disease.

RESULTS

Of 141 laboratories, 62 (44%) responded to the survey. Hospitals varied widely in their use of diagnostic testing in 2006, with 95.1% testing for meningococcal disease, but only 66.1% and 63.3% testing for legionellosis and West Nile virus disease, respectively. Most laboratories (91%) performed gram stain/culture to diagnose meningococcal disease in-house and 23% performed ova and parasite panels for giardiasis were conducted in-house. Fewer than 11% of laboratories performed in-house testing for the remaining diseases. Laboratories affiliated with small hospitals (≤100 beds) were more likely to send specimens for outside testing compared with laboratories associated with large hospitals (>250 beds). Median turnaround time for ova and parasite panel testing for giardiasis was significantly shorter for in-house testing (1.0 days) than within-system (2.25 days) or outside laboratory (3.0 days) testing (P = .0003). No laboratories reported in-house testing for meningococcal disease, pertussis, or Rocky Mountain spotted fever using polymerase chain reaction.

CONCLUSION

Many hospitals did not order diagnostic tests for important infectious diseases during 2006, even for relatively common diseases. In addition, hospital laboratories were unlikely to perform diagnostic testing in-house; sending specimens to an outside laboratory may result in substantial delays in receiving results. These unsettling findings have adverse implications for both patient care and public health surveillance; they indicate an immediate need to study nationally the use and timeliness of clinical microbiologic testing.

Community-acquired Legionella Pneumonia in the intensive care unit: Impact on survival of combined antibiotic therapy

OBJECTIVES

To compare intensive care unit (ICU) mortality in patients with severe community-acquired pneumonia (SCAP) caused by Legionella pneumophila receiving combined therapy or monotherapy.

METHODS

A prospective multicenter study was made, including all patients with sporadic, community-acquired Legionnaires' disease (LD) admitted to the ICU. Admission data and information on the course of the disease were recorded. Antibiotic prescriptions were left to the discretion of the attending physician and were not standardized.

RESULTS

Twenty-five cases of SCAP due to L. pneumophila were included, and 7 patients (28%) out of 25 died after a median of 7 days of mechanical ventilation. Fifteen patients (60%) presented shock. Levofloxacin and clarithromycin were the antibiotics most commonly used in monotherapy, while the most frequent combination was rifampicin plus clarithromycin. Patients subjected to combination therapy presented a lower mortality rate versus patients subjected to monotherapy (odds ratio for death [OR] 0.15; 95%CI 0.02-1.04; p=0.08). In patients with shock, this association was stronger and proved statistically significant (OR for death 0.06; 95%CI 0.004-0.86; p=0.04).

CONCLUSIONS

Combined antibiotic therapy decreases mortality in patients with SCAP and shock caused by L. pneumophila.

Lethal Legionella infection in an immunocompromised child: first reported case in the Middle East

Legionnaires disease continues to be underreported in the Middle East--a reflection of underdiagnosis, both clinically and by laboratory investigations. We draw the attention to this unusual cause of occasionally fatal, yet severe, pneumonia by reporting an immunocompromised infant who succumbed to Legionella pneumophila pneumonia. The urinary test for Legionella antigen was positive, and this was then confirmed by a bronchoalveolar fluid culture. Moreover we have reviewed the incidence, pathophysiology, association with immunodeficiency, diagnostic tools, and treatment in this case report.

A case of severe thrombotic thrombocytopenic purpura with concomitant Legionella pneumonia: review of pathogenesis and treatment

Thrombotic thrombocytopenia purpura (TTP) is a severe multisystem disorder characterized by fever, microangiopathic hemolytic anemia, thrombocytopenia, neurologic symptoms, and impaired renal function. Platelet counts are usually diminished, whereas the bone marrow shows a large number of megakaryocytes indicating peripheral destruction and consumption of platelets. Coagulation studies in patients with TTP are normal or slightly elevated, which helps differentiate this entity from disseminated intravascular coagulation. The peripheral smear shows an abundance of schistocytes, reticulocytes, and, at times, nucleated red blood cells. Serum lactate dehydrogenase and indirect bilirubin are elevated as a result of mechanical destruction of red blood cells. Legionella pneumophila has been identified as a relatively common cause of both community-acquired and hospital-acquired pneumonia. An association between Legionella and TTP has only been cited once in the literature. Here we present a case of severe TTP with concurrent Legionella infection. Our patient presented with the classic clinical findings of TTP and an ADAMTS13 level of less than 5% associated with an inhibitor. After a 3-week treatment course with plasma exchange, steroids, and antibiotics, he had complete clinical recovery and his ADAMTS13 level increased to greater than 75%.