Legionellosis associated with artesian well excavation

In October 1990 pneumonia due toLegionella pneumophila was diagnosed in two employees working in the area of Apulia, southern Italy, where artesian wells were in construction. Although the exposure to excavation has been associated with Legionnaires' disease, in our investigation the illness occurred only in those employees who were present when the water emerged from the ground under high pressure. On the basis of this report, water appears as the most likely reservoir of the organism and the main route of infection.Corresponding author.     

National survey of physicians in Japan regarding their use of diagnostic tests for legionellosis

IntroductionBacterial culture remains the gold standard for the diagnosis of legionellosis. However, past reports indicate that most physicians use the urinary antigen test (UAT) alone. Combining it with other tests is important, especially in patients with negative UAT results. The aim of this study was to investigate the current situation of legionellosis diagnostics and clarify the issues that need to be addressed.MethodsBetween March 1, 2021 and April 30, 2021, a questionnaire survey was conducted in an anonymous manner among physicians working in Japan. Questionnaires were generated on a website and asked questions in a multiple-choice format.ResultsValid responses were received from 309 physicians during the study period. Most (92.9%) physicians reported using UAT as the initial test for patients suspected of having legionellosis, and <10% reported using other tests (e.g., culture, nucleic acid amplification test [NAAT], Gimenez staining, and serum antibody titer measurement [ATM]). When the initial test result was negative, 63% of physicians reported not conducting additional tests. Even when they chose to run additional tests, at most 27.8%, 23.6%, 12.3%, and 10.4% of all physicians used NAAT, culture, Gimenez staining, and serum ATM, respectively. The major reasons for not using tests other than UAT were “unavailability in the medical facility,” “long turn-around time,” and “difficult to collect sputum.”ConclusionsThe present survey revealed that most physicians in Japan used UAT alone for diagnosing legionellosis. Eliminating barriers to creating a reasonable environment and edification of physicians are needed to improve the current situation.     

Comparison of clinical and environmental samples of Legionella pneumophila at the nucleotide sequence level

Legionella pneumophila serogroup 1 is the most common etiological agent of legionellosis. We have used clinical and environmental isolates from different sources to compare their genetic variability. We have obtained the nucleotide sequence for six protein-coding loci, included in the SBT scheme for L. pneumophila, and three intergenic regions from 127 samples, 47 of environmental origin and 80 from clinical samples. Levels of genetic variability were found to be higher in the environmental than in the clinical samples, but these did not represent a mere subset of the former. Not a single case of full identity between clinical and environmental isolates was found, which raises the possibility that only a specific subset of environmental isolates is actually capable of producing infection in humans. A phylogenetic analysis of the concatenate alignment of the nine loci sequences showed four main groups, each including clinical and environmental isolates, although their distribution was not uniform among them. The comparison of each individual gene tree with the others revealed several cases of incongruence involving samples from both origins, thus suggesting the presence of recombination in the two groups.     

太原地区内科住院患者军团菌抗体调查及医院感染军团菌病

用MAT及ELISA检测200例内科住院患者血清3种军团菌抗体。呼吸组Lp1抗体阳性率两种方法均高于正常人群及非呼吸组病人。Lb、Lj抗体阳性率(MAT法)住院病人高于正常人群,但呼吸组与非呼吸组间无显著差别。部分患者抗体滴度增长>4倍或持续阳性。一例临床表现、抗体检测及药物疗效显示可能为医院感染佐丹军团菌肺炎。作者强调重视医院感染军团菌病。     

改良间接免疫荧光方法在军团病诊断上的应用

本文用IFA与改良IFA法平行对Lp-I、Ⅲ~Ⅵ型与各型抗血清和有关病原体抗血清及31株肺炎病原菌与Lp各型抗血清进行交叉试验,两法结果相同。检测46例肺炎病人双份血清和116份正常人血清抗体,两法结果基本一致。证明改良IFA与原法一样,具有较高的灵敏性和特异性,可用于军团病的实验室诊断。     

儿童军团菌病危险因素的研究

用成组病例对照研究方法进行儿童军用菌病危险因素分析。单因素分析、多元逐步回归分析及非条件Ｌｏｇｉｓｔｉｃ回归模型分析，结果筛选出年龄、季节、被动吸烟、频繁接触泥土及免疫抑制剂持续应用为军团菌病的危险因素。因素分级分析显示年龄、被动吸烟程度、免疫抑制剂持续应用与该病发生有剂量－反应关系。     

湖北省十堰地区军团病调查

为了解十堰地区军团病占成人肺炎的比例,我们用间接免疫荧光试验(IFA),检测41例临床现症肺炎病人双份血清LP-抗体。LP-抗体滴度呈4倍增长14例(34.15％),滴度呈4倍增长并达到及超过1:128者7例(17.07％),参考美国疾病控制中心(CDC)对军团病的诊断标准,军团病在本次调查的肺炎病人中所占比例为17.07％。病后3～8周内抗体滴度上升4倍至1:128例数最多,可初步认为在此时间内进行第二份血清学检查较为合适。     

Actualités sur les infections à Legionella

Legionella-related disease is caused by an intracellular bacteria mainly living in water. Contamination results from inhalation of Legionella sp containing aerosolized water. Main risk factors are tobacco, immunodeficiency, and advanced age. Antigenuria is the cornerstone of the diagnosis. Immunocompromised patients, more commonly infected with non pneumophila Legionella, present negative antigenuria, and culture and PCR are essential for the diagnosis. Legionnaires’ disease may be severe, especially in elderly and/or immunocompromised patients. Mortality rate varies from 10 % in the general population to 50 % in intensive care. Treatment is based on macrolides or fluoroquinolones. Antibiotic resistance is very rare.     

Fatal legionellosis in patients with malignant hematologic diseases

Summary Pneumonia was present in 70/157 (44.6%) autopsied patients with malignant hematologic diseases. In 16/70 patients (22.9%), legionellae were found to be the causative agents by screening lung tissue specimens with the direct fluorescent antibody method. In 5/16 patients with Legionella pneumonia, in whom legionellosis had been suspected clinically, the diagnosis had already been established by serology, urinary Legionella antigen detection, and culture. These results provide evidence that legionellosis is an important pneumonia etiology in patients with malignant hematological diseases. Thus, Legionella diagnostics should be applied routinely, and antibiotics effective in the treatment of legionellosis should be added to the usual therapy in patients with etiologically unexplained pneumonias. In view of the common occurrence of relapses of Legionella pneumonia, antibiotic therapy should be continued for an extended period.