Legionella pneumonia (LP) is a relatively uncommon yet well-known type of atypical community-acquired pneumonia (CAP). It is characterized by a rapid progression to severe pneumonia and can be easily misdiagnosed. In most patients, chest computed tomography (CT) showed patchy infiltration, which may progress to lobar infiltration or even lobar consolidation. While pulmonary cavities are commonly observed in immunocompromised patients with LP, they are considered rare in immunocompetent individuals. Herein, we present a case of LP in an immunocompetent patient with multiple cavities in both lungs. Pathogen detection was performed using metagenomic next-generation sequencing (mNGS). This case highlights the unusual radiographic presentation of LP in an immunocompetent patient and emphasizes the importance of considering LP as a possible diagnosis in patients with pulmonary cavities, regardless of their immune status. Furthermore, the timely utilization of mNGS is crucial for early pathogen identification, as it provides multiple benefits in enhancing the diagnosis and prognosis of LP patients.

Legionnaires\' disease caused by the bacteria Legionella pneumophila, is considered a type of atypical pneumonia. The disease usually presents with dyspnea, cough, fever, muscle aches, headache, nausea, and vomiting. A milder form of the disease (Pontiac fever) with flu-like illness also exists. In addition to lung infection, extrapulmonary manifestations might occur including sepsis, rhabdomyolysis, neurological impairment, kidney, and liver damage. Myocarditis can be seen as a rare complication in Legionnaires\' disease. Here, we are presenting a case of Legionnaires\' disease associated with myocarditis in a patient with no predisposing risk factors for severe illness.

Legionella pneumonia, rhabdomyolysis, and acute kidney injury are called the Legionella triad, which is rare and associated with a poor outcome and even death. Early diagnosis and timely treatment are essential for these patients.
A 63-year-old man with cough, fever, and fatigue was initially misdiagnosed with common bacterial infection and given beta-lactam monotherapy but failed to respond to it. Conventional methods, including the first Legionella antibody test, sputum smear, and culture of sputum, blood, and bronchoalveolar lavage fluid (BALF) were negative. He was ultimately diagnosed with a severe infection of Legionella pneumophila by metagenomics next-generation sequencing (mNGS). This patient, who had multisystem involvement and manifested with the rare triad of Legionella pneumonia, rhabdomyolysis, and acute kidney injury, finally improved after combined treatment with moxifloxacin, continuous renal replacement therapy, and liver protection therapy.
Our results showed the necessity of early diagnosis of pathogens in severe patients, especially in Legionnaires\' disease, who manifested with the triad of Legionella pneumonia, rhabdomyolysis, and acute kidney injury. mNGS may be a useful tool for Legionnaires\' disease in limited resource areas where urine antigen tests are not available.

UNASSIGNED: Although Legionella is not the most common pathogen of community-acquired pneumonia, the epidemiological distribution of pneumonia pathogens has changed in recent years, with a gradual increase in some rare pathogens. For example, pneumonia that occurs after water source contamination is mostly caused by Legionella infection. This paper reports the diagnosis and treatment process of a patient after Legionella infection, who had misdiagnosis at the beginning, rapidly progressed to severe disease and combined with fungal infection. This article focuses on the timely and effective treatment of rapidly progressing Legionella pneumonia, in anticipation of a better understanding of the diagnosis and treatment of the disease.
UNASSIGNED: Here, we report a case of legionella infection with the nausea, vomiting as the first symptoms accompanied by weakness, chills, dizziness, abdominal discomfort in a 75-year-old female. The patient had a history of type 2 diabetes for 30 years, diabetic peripheral neuropathy for more than 20 years, arterial hypertension for 10 years, bone hyperplasia for more than 5 years, resection of right-sided thyroid cystadenoma in 1990. The patient had firstly been diagnosed with cholecystitis and gallbladder neck stones, diet abstinence, metronidazole, cefoperazone sulbactam, and rehydration were given. The patient responded poorly to these empiric treatments. The patient was given moxifloxacin in combination with azithromycin after the onset of respiratory symptoms, but the condition continued to deteriorate, and tigecycline was subsequently added. After the mechanical ventilation and the treatment plan adjusting, she improved significantly.
UNASSIGNED: Immunocompromised patient combined with underlying diseases are more susceptible to infection in an environment contaminated with Legionella, and the rapid onset and atypical respiratory symptoms make it easy to misdiagnose the disease, thus delaying treatment and leading to further deterioration. Timely diagnosis, early mechanical ventilation and rational drug administration were fundamental to treat Legionella pneumonia.

Legionella pneumonia caused by Legionella pneumophila is a multi-system disease that is a life-threatening, acute, and severe form of pneumonia. L. pneumophila is widespread and the clinical manifestations of Legionella pneumonia are similar to those of typical and atypical pneumonia. Current diagnostic scores and radiologic evidence have limited diagnostic value. Thus, it is likely that many cases of Legionella pneumonia remain unreported. We describe a woman with a medical history of acute myeloid leukemia who suffered from repeated fever, and no relief following initial empirical antibiotic treatment. Ultimately, she was diagnosed with Legionella pneumonia based on metagenomic next-generation sequencing (mNGS). We also performed a systematic review of the literature and identified 5 other patients who were diagnosed with Legionella pneumonia using mNGS, and reviewed their clinical characteristics, biological characteristics, epidemiological features, laboratory results, clinical findings, and treatments. This literature review showed that accurate etiological diagnosis is becoming increasingly essential for a definitive diagnosis and treatment strategies. The clinical manifestations of Legionella pneumonia are non-specific, and many routine laboratory diagnostic tests cannot identify Legionella. mNGS, an indispensable approach for identifying microorganisms, can provide a promising tool for the rapid and accurate etiological diagnosis methods contributing to early diagnosis, early treatment, and improved prognosis, especially for uncommon species such as L. pneumophila.

BACKGROUND: Acute fibrinous and organizing pneumonia (AFOP) is a rare clinicopathological condition. Studies in the literature have reported that AFOP may be associated with respiratory infections, such as respiratory syncytial virus, influenza virus, Pneumocystis jirovecii, Penicillium citrinum, and Chlamydia infections. However, AFOP associated with Legionella infection has not been reported previously. Here, we report a case of a patient with AFOP secondary to Sjögren\'s syndrome and Legionella infection.
METHODS: A 47-year-old man was admitted to the hospital because of fever, expectoration, and shortness of breath. Lung imaging showed irregular patchy consolidation. A diagnosis of Legionella pneumonia was initially considered on the basis of the patient\'s history of exposure to soil before disease onset, signs of extrapulmonary involvement, and a positive Legionella urine antigen test result. However, the patient\'s symptoms and lung imaging did not improve after treatment with levofloxacin, moxifloxacin, and tigecycline for Legionella infection. In addition, Sjögren\'s syndrome was diagnosed on the basis of clinical manifestations and immunological indicators. Pathological changes associated with AFOP were confirmed from the results of ultrasound-guided percutaneous lung biopsy. The patient\'s clinical symptoms improved rapidly after a short course of low-dose corticosteroid therapy, and lung imaging showed significant improvement.
CONCLUSIONS: The possibility of secondary AFOP should be considered when Legionella pneumonia does not improve after standard antibiotic therapy. Lung biopsy and histopathological examination are important for the adjustment of treatment strategy. Our case also highlights the importance of screening for autoimmune diseases in patients with AFOP.

The Infectious Diseases Society of America recommends either a fluoroquinolone or a macrolide as a first-line antibiotic treatment for Legionella pneumonia, but it is unclear which antibiotic leads to optimal clinical outcomes. We compared the effectiveness of fluoroquinolone versus macrolide monotherapy in Legionella pneumonia using a systematic review and meta-analysis.
We conducted a systematic search of literature in PubMed, Cochrane, Scopus, and Web of Science from inception to 1 June 2019. Randomized controlled trials and observational studies comparing macrolide with fluoroquinolone monotherapy using clinical outcomes in patients with Legionella pneumonia were included. Twenty-one publications out of an initial 2073 unique records met the selection criteria. Following PRISMA guidelines, 2 reviewers participated in data extraction. The primary outcome was mortality. Secondary outcomes included clinical cure, time to apyrexia, length of hospital stay (LOS), and the occurrence of complications. The review and meta-analysis was registered with PROSPERO (CRD42019132901).
Twenty-one publications with 3525 patients met inclusion criteria. The mean age of the population was 60.9 years and 67.2% were men. The mortality rate for patients treated with fluoroquinolones was 6.9% (104/1512) compared with 7.4% (133/1790) among those treated with macrolides. The pooled odds ratio assessing risk of mortality for patients treated with fluoroquinolones versus macrolides was 0.94 (95% confidence interval, .71-1.25, I2 = 0%, P = .661). Clinical cure, time to apyrexia, LOS, and the occurrence of complications did not differ for patients treated with fluoroquinolones versus macrolides.
We found no difference in the effectiveness of fluoroquinolones versus macrolides in reducing mortality among patients with Legionella pneumonia.