暂无摘要。

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。.

Among the 50 species and 70 serogroups of Legionella identified, Legionella pneumophila, comprising three subsp. (subsp. pneumophila, subsp. fraseri, and subsp. pasculleii), is recognized as the major cause of epidemic legionellosis. Rapid and reliable assays to identify pathogenic Legionella spp., and the three L. pneumophila subsp. in particular, are in great demand. In this study, we analyzed the gyrB genes of eleven Legionella spp. and subsp., comprising L. anisa, L. bozemanii, L. dumoffii, L. feeleii, L. gormanii, L. longbeachae, L. micdadei, L. waltersii, L. pneumophila subsp. pneumophila, L. pneumophila subsp. fraseri, and L. pneumophila subsp. pasculleii. We developed a rapid oligonucleotide microarray detection technique to identify accurately these common pathogenic Legionella spp. and L. pneumophila subsp. To detect multiple Legionella species with high specificity, 31 reproducible probes were designed in the array. Sixty-one strains were analyzed in total, including 37 target pathogens and 24 non-target bacterial species used to validate the microarray. The sensitivity of the detection was 1.0 ng using genomic DNA of three Legionella spp., L. anisa, L. dumoffii, and L. waltersii, or 13 CFU/100 mL using the cultured L. pneumophila subsp. pneumophila. Eight isolated strains were tested using the microarray with 100% accuracy. The data indicated that the technique is an efficient method to diagnose and detect Legionella spp. and subsp. in basic microbiology, clinical diagnosis, epidemiological surveillance, and food safety applications. In addition, a phylogenetic study based on the gyrB gene revealed the genetic relationship among the different Legionella spp. and subsp.

Virulence genes are distinct regions of DNA which are present in the genome of pathogenic bacteria and absent in nonpathogenic strains of the same or related species. Virulence genes are frequently associated with bacterial pathogenicity in genus Legionella. In the present study, an assay was performed to detect ten virulence genes, including iraA, iraB, lvrA, lvrB, lvhD, cpxR, cpxA, dotA, icmC and icmD in different pathogenicity islands of 47 Legionella reference strains, 235 environmental strains isolated from water, and 4 clinical strains isolated from the lung tissue of pneumonia patients. The distribution frequencies of these genes in reference or/and environmental L. pneumophila strains were much higher than those in reference non-L. pneumophila or/and environmental non-L. pneumophila strains, respectively. L. pneumophila clinical strains also maintained higher frequencies of these genes compared to four other types of Legionella strains. Distribution frequencies of these genes in reference L. pneumophila strains were similar to those in environmental L. pneumophila strains. In contrast, environmental non-L. pneumophila maintained higher frequencies of these genes compared to those found in reference non-L. pneumophila strains. This study illustrates the association of virulence genes with Legionella pathogenicity and reveals the possible virulence evolution of non-L. pneumophia strains isolated from environmental water.

Legionella pneumophila has been recognized as the major cause of legionellosis since the discovery of the deadly disease. Legionella spp. other than L. pneumophila were later found to be responsible to many non-pneumophila infections. The non-L. pneumophila infections are likely under-detected because of a lack of effective diagnosis. In this report, we have sequenced the 16S-23S rRNA gene internal transcribed spacer (ITS) of 10 Legionella species and subspecies, including L. anisa, L. bozemanii, L. dumoffii, L. fairfieldensis, L. gormanii, L. jordanis, L. maceachernii, L. micdadei, L. pneumophila subspp. fraseri and L. pneumophila subspp. pasculleii, and developed a rapid oligonucleotide microarray detection technique accordingly to identify 12 most common Legionella spp., which consist of 11 pathogenic species of L. anisa, L. bozemanii, L. dumoffii, L. gormanii, L. jordanis, L. longbeachae, L. maceachernii, L. micdadei, and L. pneumophila (including subspp. pneumophila, subspp. fraseri, and subspp. pasculleii) and one non-pathogenic species, L. fairfieldensis. Twenty-nine probes that reproducibly detected multiple Legionella species with high specificity were included in the array. A total of 52 strains, including 30 target pathogens and 22 non-target bacteria, were used to verify the oligonucleotide microarray assay. The sensitivity of the detection was at 1.0 ng with genomic DNA or 13 CFU/100 mL with Legionella cultures. The microarray detected seven samples of air conditioner-condensed water with 100% accuracy, validating the technique as a promising method for applications in basic microbiology, clinical diagnosis, food safety, and epidemiological surveillance. The phylogenetic study based on the ITS has also revealed that the non-pathogenic L. fairfieldensis is the closest to L. pneumophila than the nine other pathogenic Legionella spp.

BACKGROUND: The environmental sources associated with community-acquired or nosocomial legionellosis were not always detectable in the mainland of China and Hong Kong, China. The objective of this study was to illustrate the control measures implemented for nosocomial and community outbreaks of legionellosis, and to understand the environmental distribution of legionella in the water system in Hong Kong, China.
METHODS: We investigated the environmental sources of two cases of legionellosis acquired in the hospital and the community by extensive outbreak investigation and sampling of the potable water system using culture and genetic testing at the respective premises.
RESULTS: The diagnosis of nosocomial legionellosis was suspected in a patient presenting with nosocomial pneumonia not responsive to multiple beta-lactam antibiotics with subsequent confirmation by Legionella pneumophila serogroup 1 antigenuria. High counts of Legionella pneumophila were detected in the potable water supply of the 70-year-old hospital building. Another patient on continuous ambulatory peritoneal dialysis presenting with acute community-acquired pneumonia and severe diarrhoea was positive for Legionella pneumophila serogroup 1 by polymerase chain reaction (PCR) testing on both sputum and nasopharyngeal aspirate despite negative antigenuria. Paradoxically the source of the second case was traced to the water system of a newly commissioned office building complex. No further cases were detected after shock hyperchlorination with or without superheating of the water systems. Subsequent legionella counts were drastically reduced. Point-of-care infection control by off-boiled or sterile water for mouth care and installation of water filter for showers in the hospital wards for immunocompromised patients was instituted. Territory wide investigation of the community potable water supply showed that 22.1% of the household water supply was positive at a mean legionella count of 108.56 CFU/ml (range 0.10 to 639.30 CFU/ml).
CONCLUSIONS: Potable water systems are open systems which are inevitably colonized by bacterial biofilms containing Legionella species. High bacterial counts related to human cases may occur with stagnation of flow in both old or newly commissioned buildings. Vigilance against legionellosis is important in healthcare settings with dense population of highly susceptible hosts.

A total of 25 gyrB gene sequences from 20 Legionella pneumophila subsp. pneumophila strains and five L. pneumophila subsp. fraseri strains were obtained and analyzed, and a multiplex PCR for the simultaneous detection of Legionella bozemanae, Legionella longbeachae, Legionella micdadei and Legioenella pneumophila, and two single PCRs for the differentiation of L. pneumophila subsp. pneumophila and L. pneumophila subsp. fraseri were established. The multiplex PCR method was shown to be highly specific and reproducible when tested against 41 target strains and 17 strains of other bacteria species. The sensitivity of the multiplex PCR was also analyzed and was shown to detect levels as low as 1 ng of genomic DNA or 10 colony-forming units (CFUs) per milliliter in mock water samples. Sixty-three air conditioner condensed water samples from Shanghai City were examined, and the result was validated using 16S rRNA sequencing. The data reported here demonstrate that the multiplex PCR method described is efficient and convenient for the detection of Legionella species in water samples. Twenty L. pneumophila subsp. pneumophila strains and five L. pneumophila subsp. fraseri strains were used for the validation of the two L. pneumophila subspecies-specific PCR methods, and the results indicated that the two PCR methods were both highly specific and convenient for the identification of L. pneumophila at the subspecies level.

暂无摘要。

The objective of this study was to determine the antimicrobial activity of essential oils (EOs) extracted from Cinnamomum osmophloeum leaves and different tissues of Cryptomeria japonica against pathogenic Legionella pneumophila at 42 degrees C. Ten kinds of EOs were extracted by water distillation and their chemical constituents were quantified by gas chromatography-mass spectroscopy (GC-MS). The results showed that cinnamon leaf EO possessed stronger anti-L. pneumophila activity than C. japonica EO. In particular, the highest bactericidal effect was noted in contact with C. osmophloeum leaf EO of cinnamaldehyde type (characterized by its major constituent of cinnamaldehyde accounting for 91.3% of EO), regardless of contacted cell concentration (2 and 4 log CFU ml(-1)) or exposure time (10 and 60 min). Cinnamaldehyde is responsible for anti-L. pneumophila activity based on the results of antimicrobial testing and statistical analysis. Stepwise regression analyses show that EO concentration is the most significant factor affecting the bioactivity of EO. It is concluded that C. osmophloeum leaf oil of cinnamaldehyde type and its major constituent, cinnamaldehyde, possess strong anti-L. pneumophila activities, and have the great potential to be used as an antibacterial agent to control legionellosis associated with hot tubs and spa facilities widely used in homes and resorts.

A double-blind placebo-controlled trial reported the benefit of erythromycin in treating pityriasis rosea (PR), a postulated mechanism being the eradication of bacteria susceptible to erythromycin. The aim of this study was to investigate the association between PR and Chlamydia pneumoniae, C. trachomatis, Legionella longbeachae, L. micdadei, L. pneumophila, and Mycoplasma pneumoniae infections. We recruited 13 patients aged seven to 46 years (mean: 26.8 years) diagnosed to have PR in a primary care setting in 18 months. Lesional histopathology was arranged for atypical cases. Clotted blood was collected at initial presentation and four weeks later. Controls were 13 paired age-and-sex-matched patients requiring blood collection for non-dermatological diseases. Serology tests were performed in parallel but were read \"blinded\" on the acute and convalescent specimens of patients and the control subjects. The serology profiles were not diagnostic of active infection by any of the bacteria studied for all 13 patients. Two patients had four-fold increase in IgG titres against C. pneumoniae, with IgM being negative. Two patients had IgM detectable against L. pneumophila serotype 6 and M. pneumoniae respectively, with no significant rise of the specific IgG. These patients had no symptom or sign of chest infection. The seroprevalence and IgG titres of the study patients for the bacteria investigated were insignificantly different from those of control subjects. We conclude that the bacteria investigated in this study do not play a significant role in the pathogenesis of PR. We believe that anti-inflammatory and immunomodulatary effects might contribute towards the action of erythromycin, if any, in PR.