BACKGROUND: In case of pneumonia, some biological findings are suggestive for Legionnaire\'s disease (LD) including C-reactive protein (CRP). A low level of CRP is predictive for negative Legionella Urinary-Antigen-Test (L-UAT).
METHODS: Observational retrospective study in Nord-Franche-Comté Hospital with external validation in Besançon University Hospital, France which included all adults with L-UAT performed during January 2018 to December 2022. The objective was to determine CRP optimal threshold to predict a L-UAT negative result.
RESULTS: URINELLA included 5051 patients (83 with positive L-UAT). CRP optimal threshold was 131.9 mg/L, with a negative predictive value (NPV) at 100%, sensitivity at 100% and specificity at 58.0%. The AUC of the ROC-Curve was at 88.7% (95% CI, 86.3-91.1). External validation in Besançon Hospital patients showed an AUC at 89.8% (95% CI, 85.5-94.1) and NPV, sensitivity and specificity was respectively 99.9%, 97.6% and 59.1% for a CRP threshold at 131.9 mg/L; after exclusion of immunosuppressed patients, index sensitivity and NPV reached also 100%.
CONCLUSIONS: In case of pneumonia suspicion with a CRP level under 130 mg/L (independently of the severity) L-UAT is useless in immunocompetent patients with a NPV at 100%. We must remain cautious in patients with symptoms onset less than 48 h before CRP dosage.

BACKGROUND: Infections have been recognized as an uncommon cause of rhabdomyolysis, with evidence indicating a worse prognosis when compared to rhabdomyolysis caused by other etiologies. Diseases caused by Legionella pneumophila can present variably, ranging from mild to severe illness, as is sometimes the case with pneumonia. In particular, the triad of Legionnaire\'s disease, rhabdomyolysis, and acute kidney injury is associated with a significant increase in the morbidity and mortality, with most patients requiring initiation of renal replacement therapy such as hemodialysis. While the exact mechanism of both the muscle and kidney injury in this setting remains unknown, several hypotheses exist, with some research suggesting multiple yet distinct processes occurring in both target organs.
METHODS: In this case report, we describe a 53-year-old African American man who presented with Legionella pneumophila pneumonia complicated by rhabdomyolysis and acute kidney injury. He was treated with aggressive fluid resuscitation and a 2-week course of azithromycin. His clinical status improved without necessitating renal replacement therapy or mechanical ventilation. We postulate that early recognition and treatment were key to his recovery. He was discharged 10 days later without recurrence of rhabdomyolysis at the time of this report.
CONCLUSIONS: While there are several well-established and more common causes of rhabdomyolysis, clinicians should recognize Legionella sp. as an etiology, given its association with significant morbidity and mortality.

Legionnaires\' disease is caused by a potentially life-threatening infection with the opportunistic Gram-negative bacilli species Legionella pneumophila, which is transmitted via inhalation or aspiration of water droplets. Legionnaires\' commonly presents as atypical community-acquired pneumonia with accompanying diarrhea. Although hepatic and renal involvement are relatively uncommon, in this report, we present a case of Legionella pneumonia with acute hepatitis.

Organizing pneumonia is a rare subtype of interstitial lung disease that can occur following infectious alveolar insults. Imaging often demonstrates bilateral patchy opacification while biopsy reveals irregular alveolar fibrosis. Steroids are the treatment of choice, resulting in rapid clinical improvement. In this report, we describe a 69-year-old woman with a recent hospitalization for Legionella pneumonia who presented with worsening dyspnea and radiographic evidence of bilateral patchy infiltrates. Differential diagnoses included Legionella treatment failure and organizing pneumonia, therefore she was managed with both antibiotics and steroids. Her clinical status improved significantly the day after treatment initiation, making organizing pneumonia as the likely culprit for her initial decompensation. In patients with a recent history of lung injury who present with acute hypoxic respiratory failure, one must have a high index of suspicion for organizing pneumonia, for prompt treatment often results in rapid recovery.

Preliminary research has suggested possible associations between natural waterways and Legionella infection, and we previously explored these associations in eastern Wisconsin using positive L. pneumophila serogroup 1 urine antigen tests (LUAT) as diagnostic. This case-control study was a secondary analysis of home address data from patients who underwent LUAT at a single eastern Wisconsin health system from 2013 to 2017. Only zip codes within the health system\'s catchment area that registered ≥3 positive cases and ≥50 completed tests, as well as geographically adjacent zip codes with ≥2 positive cases and ≥50 tests, were included. A 1:3 ratio of cases to randomly selected controls was used. Home addresses were geocoded and mapped using ArcGIS software (Esri); nearest waterway and distance to home was identified. Distance to nearest waterway according to ArcGIS was verified/corrected using Google Maps incognito. Distances were analyzed using chi-squared and 2-sample t-tests. Overall, mean distance to nearest waterway did not differ between cases (2958 ± 2049 ft) and controls (2856 ± 2018 ft; P=0.701). However, in a subset of nonurban zip codes, cases were closer to nearest waterway than controls (1165 ± 905 ft vs 2113 ± 1710 ft; P=0.019). No association was found between cases and type of waterway. Further research is needed to investigate associations and differences between natural and built environmental water sources in relation to legionellosis.

Infection with Legionella spp. (legionellosis) causes two distinct clinical presentations: Legionnaires\' Disease and Pontiac Fever. Legionnaire\'s Disease primarily involves the lungs, often with accompanying gastrointestinal symptoms, and can also affect the liver, central nervous system, and kidneys, and cause metabolic derangements. Manifestations in the integumentary system are rare; to date, there have been eleven cases reported in the literature of Legionellosis with associated rash, with varied presentation. The relationship between Legionella pneumophila and the skin has not yet been clearly defined; immunological and/or toxic pathogenesis are possible. We report a case of Legionnaires\' Disease in a young immunocompromised man with a largely benign clinical course consisting of predominantly gastrointestinal symptoms and an extensive maculopapular rash. Chest radiography showed lobar infiltrate in the absence of clinical symptoms of pneumonia. The importance of this case is for clinicians to maintain high clinical suspicion for Legionella when extra-pulmonary symptoms predominate, specifically in immunocompromised hosts who may have atypical presentations and have higher mortality rates when treatment is delayed.

This report describes a combined immunofluorescence and fluorescence viability stain applied as one staining solution for rapid detection of live Legionella pneumophila in mixed bacterial populations. Instead of sequential viability staining with the Invitrogen BacLight LIVE/DEAD staining kit followed by antibody-Alexa Fluor (AF) 647 conjugate staining to identify live L. pneumophila, a combined single cocktail solution staining protocol was developed to simplify and accelerate the time to detection of viable L. pneumophila serogroup-1 (SG-1) in mixed species populations on a filter membrane. The stain cocktail will aid in accelerating fluorescence microscopic analysis of cooling tower, air conditioner and water fountain or other liquid samples for the presence of L. pneumophila and its viability status. Visibly red stained cells were identified as dead non-L. pneumophila SG-1 cells, while green fluorescing cells represented viable non-L. pneumophila SG-1 cells. Due to also staining red with antibody-AF 647, L. pneumophila SG-1 cells were pseudocolorized as blue to distinguish them from other dead cells. Fluorescence color emission mixing from the viability dyes (SYTO 9 and propidium iodide) with antibody-AF 647 stained L. pneumophila led to other fluorescent colors. For example, green plus pseudocolorized blue AF 647-antibody- labeled cells were identified as live cyan-colored L. pneumophila SG-1 cells. Magenta-colored cells resulted from dead L. pneumophila cells that combined red propidium iodide with blue pseudocolorized AF 647-antibody emissions. Analysis of measured RGB (red, green, blue) color values in microscopic images of mixed bacterial populations suggests the possibility of facile automated discrimination of subpopulations of live and dead L. pneumophila and non-L. pneumophila species by computers in 3-dimensional RGB color space after staining in the combined cocktail which will save time for more rapid microscopic detection of potential sources of Legionnaire\'s disease.

Given the importance of disinfecting showerheads from Legionella species and the lack of instructions as to how to successfully achieve this, the aim of this study was to examine the ability of domestic steam disinfection to successfully disinfect showerheads from Legionella species. Steam disinfection of Legionella pneumophila [n=3; L. pneumophila serogroup 2-15 (wildtype environmental water isolate); L. pneumophila serogroup 1 NCTC11192 (reference strain); L. pneumophila serogroup 1 (wildtype environmental water isolate)], L. erythra (wildtype environmental water isolate) and L. bozemanii CRM11368M (reference strain) were examined in this study. Steam disinfection employing a baby bottle steam disinfector device eradicated all Legionella organisms tested. Steam disinfection, when performed properly under the manufacturer\'s instructions, offers a relatively inexpensive, simple, versatile and widely available technology for the elimination of Legionella species from contaminated showerheads. We therefore advocate the employment of such devices to regularly disinfect showerheads and shower tubing in hairdressing salons, barber shops and gyms, as a critical control in the elimination of these organisms from these sources, thereby enhancing customer/client/staff safety.

Legionella longbeachae pneumonia is much less common than Legionella pneumophila pneumonia in most of the world and may evade timely diagnosis in settings that rely primarily on urine antigen testing, which detects Legionella pnuemophila serogroup 1 only. It is, however, widely recognized in Australia and New Zealand, where it is endemic and associated with exposure to compost and potting soils, rather than contaminated water systems as seen with L. pneumophila. L. longbeachae can cause a similar spectrum and severity of illness as L. pneumophila. Here we present a case of a 47-year-old man with L. longbeacheae necrotizing pneumonia following exposure to possibly contaminated soil from a wastewater treatment facility. Initial presentation included cough, chest pain, and dyspnea, and progressed to hypoxic respiratory failure, tension pneumothorax, and cardiac arrest. L. pneumophila urine antigen was negative, but bronchioalveolar lavage samples grew L. longbeachae on buffered charcoal yeast extract agar. A review of cases reported in the literature in non-endemic regions over a 20-year period identified 38 cases in Europe, 33 in Asia, and 8 in North America. Average age was 65, 65 % were male, and 35 % had potentially relevant environmental exposures. L. longbeachae should be considered in cases of severe community acquired pneumonia, particularly following a consistent environmental exposure or if initial testing for other pathogens is unrevealing. A thorough exposure history including questions about contact with potting soil or compost, and utilization of specialized agar for culture can both be key in identifying this pathogen.

BACKGROUND: Legionnaire\'s disease is one of the major causes of community-acquired pneumonia and is occasionally complicated by neurological symptoms. However, reports of ocular lesions due to Legionnaire\'s disease are limited.
METHODS: We report the case of a patient with Legionnaire\'s disease presenting as bilateral central scotomata due to retinal lesions. The patient consulted due to fever and bilateral central scotomata, as well as other extrapulmonary symptoms. Optical coherence tomography (OCT) showed bilateral accumulations of fluid under the retina, and the patient was diagnosed with bilateral exudative retinal detachment. Later, Legionnaire\'s disease was confirmed by pulmonary infiltrates on chest imaging and positive urinary antigen for Legionella pneumophila. After administration of antibiotics, the bilateral central scotomata and bilateral subretinal fluid accumulations completely resolved, as did the other extrapulmonary symptoms and the pulmonary infiltrates. Thus, the bilateral central scotomata due to exudative retinal detachment were thought to be caused by Legionnaire\'s disease.
CONCLUSIONS: This case demonstrates that Legionnaire\'s disease can present as bilateral central scotomata. We may consider the possibility of extrapulmonary involvement complicating Legionnaire\'s disease when we encounter bilateral ocular lesions in patients with fever and pneumonia.