Over the past two decades, the incidence of legionellosis has been steadily increasing in the United States though there is noclear explanation for the main factors driving the increase. While legionellosis is the leading cause of waterborne outbreaks in the US, most cases are sporadic and acquired in community settings where the environmental source is never identified. This scoping review aimed to summarise the drivers of infections in the USA and determine the magnitude of impact each potential driver may have. A total of 1,738 titles were screened, and 18 articles were identified that met the inclusion criteria. Strong evidence was found for precipitation as a major driver, and both temperature and relative humidity were found to be moderate drivers of incidence. Increased testing and improved diagnostic methods were classified as moderate drivers, and the ageing U.S. population was a minor driver of increasing incidence. Racial and socioeconomic inequities and water and housing infrastructure were found to be potential factors explaining the increasing incidence though they were largely understudied in the context of non-outbreak cases. Understanding the complex relationships between environmental, infrastructure, and population factors driving legionellosis incidence is important to optimise mitigation strategies and public policy.

Extrapulmonary manifestations of infection with Legionella species, of which 24 may cause disease in humans, are very rare. Here, we describe a case of a 61-year-old woman with no history of immunosuppression presenting with pain and swelling of her index finger after a prick by rose thorns during gardening. Clinical examination showed fusiform swelling of the finger with mild redness, warmth, and fever. The blood sample revealed a normal white blood cell count and a slight increase in C-reactive protein. Intraoperative observation showed extensive infectious destruction of the tendon sheath, while the flexor tendons were spared. Conventional cultures were negative, while 16S rRNA PCR analysis identified Legionella longbeachae that also could be isolated on buffered charcoal yeast extract media. The patient was treated with oral levofloxacin for 13 days, and the infection healed quickly. The present case report, with a review of the literature, indicates that Legionella species wound infections may be underdiagnosed due to the requirement for specific media and diagnostic methods. It emphasizes the need for heightened awareness of these infections during history taking and clinical examination of patients presenting with cutaneous infections.

OBJECTIVE: According to current knowledge about legionella transmission, healthcare workers (HCWs) are at an increased risk of exposure. The aim of this research was to systematically review the literature about HCWs\' exposure to legionella and establish whether there is an occupational risk.
METHODS: This was a systematic review and meta-analysis.
METHODS: PubMed, Scopus and Web of Science were searched to identify studies regarding the occupational risk of legionellosis for HCWs. Keywords used in the search were \'Legionella pneumophila\', \'occupational medicine\', \'occupational\' and \'risk\'. Selected studies were reviewed to assess the quality and meta-analysed. Finally, the nine epidemiological principles of Bradford-Hill criteria were used to assess whether legionellosis could be considered an occupational risk for HCWs.
RESULTS: The search strategy retrieved 124 studies, and 10 studies were included in the present review. The overall study quality was low. The pooled odds ratio estimate was 2.45 (95% confidence interval: 1.52-3.96). The assessment using Bradford-Hill criteria showed that only two criteria (plausibility and coherence) were met, which is insufficient to establish an occupational risk.
CONCLUSIONS: This systematic review suggests that there is a higher risk of legionella exposure for HCWs, but there is currently no clinical evidence. Further studies with appropriate study design are needed to determine whether legionella infection is an occupational risk for HCWs.

A number of studies suggest that meteorological conditions are related to the risk of Legionnaires\' disease (LD) but the findings are not consistent. A systematic review was conducted to investigate the association of weather with sporadic LD and highlight the key meteorological conditions related to this outcome. PubMed, EMBASE, The Cochrane Library and OpenGrey were searched on 26-27 March 2020 without date, language or location restrictions. Key words included \"legionellosis\", \"legionnaires\' disease\", combined with \"meteorological conditions\", \"weather\", \"temperature\", \"humidity\", \"rain\", \"ultraviolet rays\", \"wind speed\", etc. Studies were excluded if they did not examine the exposure of interest, the outcome of interest and their association or if they only reported LD outbreak cases. The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and it was registered in PROSPERO (#CRD42020168869). There were 811 articles, of which 17 were included in the review. The studies investigated different meteorological variables and most of them examined the combined effect of several variables. The most commonly examined factors were precipitation and temperature, followed by relative humidity. The studies suggested that increased precipitation, temperature and relative humidity were positively associated with the incidence of LD. There was limited evidence that higher wind speed, pressure, visibility, UV radiation and longer sunshine duration were inversely linked with the occurrence of LD. A period of increased but not very high temperatures, followed by a period of increased precipitation, favour the occurrence of LD. Increased awareness of the association of temperature and precipitation and LD occurrence among clinicians and public health professionals can improve differential diagnosis for cases of sporadic community-acquired pneumonia and at the same time contribute to improving LD surveillance.

BACKGROUND: The goal of the study was to analyze the clinical characteristics of Legionella cases caused by Legionella micdadei and explore the diagnosis and treatment.
METHODS: The pathogen was identified by routine isolation and culture, biochemical identification, serum agglutination test, mass spectrometry identification, and routine PCR. Combined with the related literature review, the clinical diagnosis and treatment of Legionella micdadei were analyzed.
RESULTS: The patient suffered from pulmonary infection caused by Legionella micdadei. After treatment with moxi-floxacin for 2 weeks, the body temperature dropped and the shadow of the lung was completely absorbed after 2 months. Combined with literature analysis, 8 cases of Legionella micetidis, including 7 males and 1 female, aged from 27 to 57 years old, 6 cases with basic diseases, which were treated with azithromycin, erythromycin or levofloxacin, and all of them achieved good therapeutic effect.
CONCLUSIONS: The detection of Legionella should be strengthened in patients with pneumonia whose symptoms have no obvious improvement after antibiotic treatment. Azithromycin, erythromycin or levofloxacin are effective in the treatment of Legionella spp.
BACKGROUND:

Legionnaires\' disease (LD) (Legionella) is a common cause of community-acquired pneumonia (CAP) in those requiring hospitalization. Geographical variation in the importance of Legionella species as an aetiologic agent of CAP is poorly understood. We performed a systematic review and meta-analysis of population-based observational studies that reported the proportion of Legionella infection in patients with CAP (1 January 1990 to 31 May 2020). Using five electronic databases, articles were identified, appraised and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The quality of the included studies was assessed using the Newcastle-Ottawa Scale. Univariate and multivariate meta-regression analyses were conducted using study design, WHO region, study quality and healthcare setting as the explanatory variables. We reviewed 2778 studies, of which 219 were included in the meta-analysis. The mean incidence of CAP was 46.7/100,000 population (95% CI: 46.6-46.8). The mean proportion of Legionella as the causative agent for CAP was 4.6% (95% CI: 4.4 to 4.7). Consequently, the mean Legionella incidence rate was 2.8/100,000 population (95% CI: 2.7-2.9). There was significant heterogeneity across all studies I2 = 99.27% (p < 0.0001). After outliers were removed, there was a decrease in the heterogeneity (I2 = 43.53%). Legionella contribution to CAP has a global distribution. Although the rates appear highest in high income countries in temperate regions, there are insufficient studies from low- and middle-income countries to draw conclusions about the rates in these regions. Nevertheless, this study provides an estimate of the mean incidence of Legionella infection in CAP, which could be used to estimate the regional and global burden of LD to support efforts to reduce the impact of this infection as well as to fill important knowledge gaps.

BACKGROUND: Urinary antigen tests (UATs) have been used for the early detection of legionellosis and have demonstrated moderate sensitivity and high specificity. However, the most recent systematic review and meta-analysis published in 2009 evaluated the accuracy of UATs; since then, UAT accuracy may have changed owing to advances and developments in UAT technology and epidemiological changes in the frequency of Legionella species that cause legionellosis. Therefore, this systematic review and meta-analysis aimed to update the accuracy of UATs for legionellosis among patients with suspected pneumonia.
METHODS: Overall, 1326 studies were screened, 21 of which fulfilled the eligibility criteria for quality assessment and meta-analysis. Data from 5772 patients, including 1368 (23.7%) with the target condition (i.e., suspected legionellosis), were included in the analysis. The overall quality of the included studies, which was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, was unclear.
RESULTS: The calculated pooled sensitivity and specificity were 0.79 (95% confidence interval [CI], 0.71-0.85) and 1.00 (95% CI, 0.99-1.00), respectively. Subpopulation analysis revealed that the accuracy of UATs for sensitivity and specificity for Legionella pneumophilia serogroup 1 was 0.86 (95% CI, 0.78-0.91) and 1.00 (95% CI, 0.99-1.00), respectively.
CONCLUSIONS: This study demonstrated that the sensitivity and specificity of UATs were moderate and high, respectively, which is comparable to the results reported in 2009. Therefore, UATs may be a useful method for the early detection of legionellosis caused by Legionella pneumophila serogroup 1.
BACKGROUND: The review protocol was prospectively registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000041080).

As a type of Legionella bacteria, Legionella longbeachae bacteria can lead to very rare legionella disease case in China with clinical characteristics, such as no typical early clinical symptoms, strong toxicity, high mortality, and not easy to detect by conventional etiology. A case of severe pneumonia caused by Legionella longbeachae infection was confirmed by bronchoalveolar lavage fluid pathogen metagenomics, and the patient\'s condition was improved after targeted anti-infection treatment. At present, our understanding in Legionella longbeachae severe pneumonia is limited. The diagnosis and treatment process of the patient with severe pneumonia of Legionella longbeachaeis retrospectively analyzed and the relevant literature was reviewed to provide the experience for its future diagnosis and treatment.
长滩军团菌作为军团菌的一种，其导致的军团菌病在国内十分罕见，且患者早期临床症状不典型、毒力强、致死率高，常规病原学检测不易检出。通过支气管肺泡灌洗液病原宏基因组学确诊了1例长滩军团菌感染所致的重症肺炎患者，在针对性抗感染治疗后患者病情好转。目前对长滩军团菌性肺炎认识有限，本文通过回顾性分析1例收治的长滩军团菌性重症肺炎患者的诊断、治疗过程，并对相关文献进行复习，可对其以后的诊断、治疗提供经验。.

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.

Herein, we report the case of a 74-year-old man diagnosed with Legionella pneumonia detected by Loop-Mediated Isothermal Amplification (LAMP) method, which was suspected to have been transmitted from the potting soil. Legionella longbeachae was identified in the sputum culture. The patient was intubated and maintained on mechanical ventilation. Antimicrobial therapy with azithromycin was also administered. His symptoms were resolved and he was discharged after 26 days of hospitalization. Legionella longbeachae pneumonia rarely occurs in Japan, and published literature of Legionella longbeachae pneumonia cases in Japan was reviewed. Patients with severe pneumonia exposed to potting soils, but with negative urinary antigen test results, should be examined by LAMP method.