Legionella pneumonia and HIV: case reports and review of the literature

Effects of cannabis smoking on the respiratory system: A state-of-the-art review

The diminished perception of the health risks associated with the consumption of cannabis (marijuana) lead to a progressive increase in its inhalational use in many countries. Cannabis can be smoked through the use of joints, spliffs and blunts, and it can be vaporised with the use of hookah or e-cigarettes. Delta-9 tetrahydrocannabinol (THC) is the main psychoactive component of cannabis smoke but contains numerous other substances. While the recreational use of cannabis smoking has been legalised in several countries, its health consequences have been underestimated and undervalued. The purpose of this review is to critically review the impact of cannabis smoke on the respiratory system. Cannabis smoke irritates the bronchial tree and is strongly associated with symptoms of chronic bronchitis, with histological signs of airway inflammation and remodelling. Altered fungicidal and antibacterial activity of alveolar macrophages, with greater susceptibility to respiratory infections, is also reported. The association with invasive pulmonary aspergillosis in immunocompromised subjects is particularly concerning. Although cannabis has been shown to produce a rapid bronchodilator effect, its chronic use is associated with poor control of asthma by numerous studies. Cannabis smoking also represents a risk factor for the development of bullous lung disease, spontaneous pneumothorax and hypersensitivity pneumonitis. On the other hand, no association with the development of chronic obstructive pulmonary disease was found. Finally, a growing number of studies report an independent association of cannabis smoking with the development of lung cancer. In conclusion, unequivocal evidence established that cannabis smoking is harmful to the respiratory system. Cannabis smoking has a wide range of negative effects on respiratory symptoms in both healthy subjects and patients with chronic lung disease. Given that the most common and cheapest way of assumption of cannabis is by smoking, healthcare providers should be prepared to provide counselling on cannabis smoking cessation and inform the public and decision-makers.

Community-acquired versus nosocomial Legionella pneumonia: factors associated with Legionella-related mortality

Over the past decade, changes in the diagnosis and management of Legionella pneumonia occurred and risk factors for severe infection and increased mortality were identified. Previous reports found that nosocomial infection is associated with higher mortality while others showed no differences. We aimed to evaluate the differences in the clinical course and mortality rates between hospital-acquired pneumonia (HAP) and community-acquired pneumonia (CAP) caused by Legionella pneumophila. A retrospective cohort study of patients admitted due to Legionella pneumonia between January 2012 through November 2019 was conducted in a tertiary referral center (Rambam Health Care Campus, Haifa, Israel). The primary outcome was 30-day Legionella pneumonia-related mortality. A multivariable logistic regression was performed to determine whether a nosocomial infection is an independent predictor of mortality. One hundred nine patients were included. Seventy (64.2%) had CAP and 39 (35.8%) had HAP. The groups were comparable regarding age, gender, and comorbidities. Time to diagnosis was longer and the number of patients receiving initial empiric anti-Legionella spp. treatment was smaller in the HAP group (8 days [IQR 5.5-12.5] vs. 5 days [IQR 3-8], p < 0.001 and 65.5% vs. 78.6%, p = 0.003, respectively). Patients with HAP had higher 30-day mortality, 41% vs. 18.6%, p = 0.02. In a multivariable logistic regression model, only pneumonia severity index and nosocomial source were independently associated with increased mortality. HAP caused by Legionella spp. is independently associated with increased mortality when compared to CAP caused by the same pathogen. The possible reasons for this increased mortality include late diagnosis and delayed initiation of appropriate treatment.

Legionella co-infection in HIV-associated pneumonia

Due to poor diagnostics and increased co-infections, HIV-associated Legionella infections are underreported. We aimed to retrospectively determine the frequency of Legionella infections in bronchoalveolar lavage (BAL) from HIV-associated pneumonia patients hospitalized in Medellin, Colombia, between February 2007 and April 2014. Although culture was negative, 17 BAL (36%) were positive for Legionella by quantitative polymerase chain reaction, most of which were in the Mycobacterium tuberculosis or Pneumocystis jirovecii co-infected patients, and included L. anisa (n = 6), L. bozemanae (n = 4), L. pneumophila (n = 3), and L. micdadei (n = 2). All L. bozemanae and L. micdadei associated with Pneumocystis, while all L. pneumophila associated with M. tuberculosis. Legionella probable cases had more complications and higher mortality rates (P = 0.02) and were rarely administered empirical anti-Legionella therapy while in hospital. Clinicians should be aware of the possible presence of Legionella in HIV and M. tuberculosis or P. jirovecii co-infected patients.

Community-acquired bacterial pneumonia in adult HIV-infected patients

INTRODUCTION

Despite active antiretroviral therapy (ART), community-acquired pneumonia (CAP) remains a major cause of morbidity and mortality among human immunodeficiency virus (HIV)-infected patients and incurs high health costs. Areas covered: This article reviews the most recent publications on bacterial CAP in the HIV-infected population, focusing on epidemiology, prognostic factors, microbial etiology, therapy, and prevention. The data discussed here were mainly obtained from a non-systematic review using Medline, and references from relevant articles. Expert commentary: HIV-infected patients are more susceptible to bacterial CAP. Although ART improves their immune response and has reduced CAP incidence, these patients continue to present increased risk of pneumonia in part because they show altered immunity and because immune activation persists. The risk of CAP in HIV-infected patients and the probability of polymicrobial or atypical infections are inversely associated with the CD4 cell count. Mortality in HIV-infected patients with CAP ranges from 6% to 15% but in well-controlled HIV-infected patients on ART the mortality is low and similar to that seen in HIV-negative individuals. Vaccination and smoking cessation are the two most important preventive strategies for bacterial CAP in well-controlled HIV-infected patients on ART.

Legionnaires' Disease Complicated with Rhabdomyolysis and Acute Kidney Injury in an AIDS Patient

Objective

To present a case of an uncommon triad of Legionella pneumonia, rhabdomyolysis, and renal failure, with review of the relevant literature.

Case

A 51-year-old with a history of human immunodeficiency virus (HIV), chronic obstructive pulmonary disease (COPD), and hypertension presented with fever, cough, and shortness of breath over four days. Chest X-ray showed consolidation in left lower lung field; urine was positive for Legionella antigen and myoglobin; creatine kinase was 51092U/L; creatine was 6.9 mg/dL, and his CD4 count was 41 cells/ul. He was managed with azithromycin and levofloxacin and further required dialysis and ventilatory support in the intensive care unit due to renal failure and respiratory failure. He responded well to the treatment and made a complete recovery. Legionella pneumophila infection is a recognized but rare cause of rhabdomyolysis with high morbidity and mortality when there is extrapulmonary involvement. Early diagnosis and appropriate treatment is essential to improve outcomes.

Conclusion

Physicians should consider Legionella pneumonia in patients with rhabdomyolysis, renal failure, and respiratory symptoms. Early diagnosis and treatment have been shown to have good clinical response. Timely intensive care management, together with early and judicious use of dialysis in patients complicated with rhabdomyolysis and renal failure, may lead to good outcomes.

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.

Microbiology and Epidemiology of Legionnaire's Disease

Legionnaire's disease (LD) is the pneumonic form of legionellosis caused by aerobic gram-negative bacilli of the genus Legionella. Individuals become infected when they inhale aerosolized water droplets contaminated with Legionella species. Forty years after the identification of Legionella pneumophila as the cause of the 1976 pneumonia outbreak in a hotel in Philadelphia, we have non-culture-based diagnostic tests, effective antibiotics, and preventive measures to handle LD. With a mortality rate still around 10%, underreporting, and sporadic outbreaks, there is still much work to be done. In this article, the authors review the microbiology, laboratory diagnosis, and epidemiology of LD.

Legionnaires' Disease: Clinicoradiological Comparison of Sporadic Versus Outbreak Cases

BACKGROUND

In 2015, New York City experienced the worst outbreak of Legionnaires’ disease in the history of the city. We compare patients seen during the 2015 outbreak with sporadic cases of Legionella during the past 5 years.

METHODS

We conducted a retrospective chart review of 90 patients with Legionnaires’ disease, including sporadic cases of Legionella infection admitted from 2010 to 2015 (n = 55) and cases admitted during the 2015 outbreak (n = 35).

RESULTS

We saw no significant differences between the 2 groups regarding demographics, smoking habits, alcohol intake, underlying medical disease, or residence type. Univariate and multivariate analyses showed that patients with sporadic case of Legionella had a longer stay in the hospital and intensive care unit as well as an increased stay in mechanical ventilation. Short-term mortality, discharge disposition, and most clinical parameters did not differ significantly between the 2 groups.

CONCLUSIONS

We found no specific clinicoradiological characteristics that could differentiate sporadic from epidemic cases of Legionella. Early recognition and high suspicion for Legionnaires’ disease are critical to provide appropriate treatment. Cluster of cases should increase suspicion for an outbreak.

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.

Legionellosis in the occupational setting

Legionellosis is the common name for two infections, Legionnaires' disease (LD) and Pontiac fever (PF), both caused by Legionella bacteria. Although with low incidence, LD is an important cause of community- and hospital-acquired pneumonia. Among community-acquired cases, an increasing number was reported to be linked to the occupational setting, posing the need for better recognition of work activities at risk of legionellosis. In this work, we selected and reviewed relevant literature on cases of occupational legionellosis published between 1978 and 2016 in order to define the: i) etiology; ii) sources of infection, iii) work activities at risk, iv) infection rates, v) predisposing factors, vi) mortality and vii) country distribution. To our knowledge, this is the first review to provide an analysis of cases of occupational legionellosis. A literature search in the PubMed website was started on January 31, 2015 and ended on June 30, 2016. Cases of occupational legionellosis documented in the scientific literature were retrieved from PubMed upon interrogation with the following keywords: "Legionella pneumophila", "Legionnaires' disease", "Pontiac fever", and "legionellosis", in combination with "employees", "workers", and "occupational". Abstracts were reviewed, and applicable articles were obtained. Only articles that met the inclusion criteria were considered. Forty-seven articles were selected, reporting confirmed cases of legionellosis which occurred over 66 years (1949-2015), and involved 805 workers (221, LD; 584, PF). Fatalities were all associated with LD, resulting in 4.1% mortality. The most common etiologic agents were Legionella pneumophila (58.5%) and Legionella feeleii (39.4%), the latter being responsible for only one large outbreak of PF. Workplaces more frequently associated with occupational legionellosis were industrial settings (62.0%), office buildings (27.3%) and healthcare facilities (6.3%), though cases were also reported from a variety of workplaces, e.g. artesian excavation and horticultural sites, lorry parks, ships, water and sewage plants. With few exceptions, cases occurred in industrialized countries of the northern hemisphere. Overall, our review highlights an extended spectrum of occupational categories at risk for legionellosis. For all categories, infection originated from exposure to work-generated aerosols contaminated with Legionella spp., and industrial facilities equipped with cooling towers or coolant systems were the most common occupational settings. These observations should raise awareness of the risk of acquiring legionellosis at work, and help to improve prevention and control measures for this infrequent but still problematic disease.

Lower Respiratory Tract Infections

This review will focus on the infectious etiologies and more common noninfectious causes of lower respiratory tract syndromes among major immunosuppressed populations. The changing epidemiology of infections in the era of highly active antiretroviral therapy (HAART) in the case of HIV-positive patients and the impacts of both newer immune-suppressant therapies and anti-infective prophylaxis for other immunocompromised hosts will be discussed, with emphasis on diagnostic approaches and practice algorithms.

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.

Legionnaires disease presenting as acute kidney injury in the absence of pneumonia

Legionnaires disease is a pneumonic illness with multisystem involvement. In 1987, Haines et al reported the only reported case of isolated renal disease of legionellosis without concurrent respiratory disease. A 62-year-old man presented with generalised weakness and malaise and watery diarrhoea, and was found to have acute kidney injury on admission. He was initially managed as acute gastroenteritis complicated with dehydration and acute kidney injury with intravenous hydration. Despite adequate hydration, his renal function was worsening day by day. Later in the course of his sickness he developed pneumonic illness and was diagnosed with Legionnaires disease after a positive urine antigen test. We are reporting the second case of Legionnaires disease presenting as an isolated acute kidney injury in the absence of respiratory symptoms on presentation.

Legionella pneumophila infection presenting as headache, confusion and dysarthria in a human immunodeficiency virus-1 (HIV-1) positive patient: case report

Background

Legionella pneumophila is a common cause of community-acquired pneumonia. Central nervous system dysfunction is common, and diagnosis in the absence of pulmonary symptoms can be challenging. Here we describe an atypical clinical presentation of Legionella infection in a patient with HIV who was found to have an unusual neuroradiologic lesion that further served to obscure the diagnosis. This is the first such description in a patient with Legionellosis and HIV coinfection.

Case presentation

A 43 year-old HIV positive man presented to our hospital with dysarthria, fevers, headache, and altered mental status. Initial work-up revealed pneumonia and a lesion of the splenium of the corpus callosum on magnetic resonance imaging. He was subsequently diagnosed with Legionella pneumonia and treated with complete symptom resolution.

Conclusions

Neurologic abnormalities are frequent in Legionellosis, but the diagnosis may be difficult in the absence of overt respiratory symptoms and in the presence of HIV coinfection. A high index of suspicion and early initiation of empiric antibiotics is imperative since early treatment may help prevent long-term sequelae. Neuroimaging abnormalities, though rare, can help the physician narrow down the diagnosis and avoid unnecessary invasive testing. Future studies should aim to elucidate the as yet unknown role of neuroimaging in the diagnoses and prognostication of Legionellosis, as well as the interaction between Legionella infection and HIV.