嗜肺性军团菌的遗传学

嗜肺性军团菌是人类呼吸道疾病一军团病的致病菌。本菌为需氧性革兰氏阴性杆菌,广泛分布于水环境中。嗜肺性军团菌对人的致病性是由于本菌能进入肺泡巨噬细胞和单核细胞内,并且可以繁殖的缘故。由于嗜肺性军团菌也可以在实验室人工培养基上生长,故将其分类为兼性细胞内致病菌。对嗜肺性军团菌和人单核吞噬细胞间的相互作用已做过十分详细的检查。嗜肺性军     

肠胃的守护军团——嗜酸乳杆菌

人的胃部是个小型“消毒车间”，绝大多数细菌都无法在这种环境下生存。但在这种“恶劣”的条件下，却有一种致病菌，不仅能在胃中定居、繁殖，还导致多种胃病的发生，它们就是幽门螺杆菌，医生常简称Hp。     

水中嗜肺军团菌检测基础培养基的质量分析

目的为保证水中嗜肺军团菌检测的准确性,对市售的4家厂商的BCYE培养基进行质量分析。方法选取嗜肺军团菌标准株和环境分离株,经过不同处理方式(酸处理、热处理)后分别接种4家厂商的BCYE培养基,对菌落结果进行计数,参考ISO 11133:2014(E)计算生长率,评估检出限。结果嗜肺军团菌标准株和环境分离株在不同处理方式、不同厂商的BCYE培养基的生长率均大于0.5,符合ISO 11133:2014(E)对合格培养基生长率的规定,经Levene方差齐性检验,生长率间比较,差异无统计学意义(P0.05)。除1家厂商的BCYE培养基对嗜肺军团菌标准株的检出限为100 CFU/ml外,其他家厂商的检出限可达到10 CFU/ml。结论 4家厂商的BCYE培养基在生长率评定中均为合格,但有2家对嗜肺军团菌标准株的检出限较高,其可能对活性较弱的嗜肺军团菌检出有一定影响。     

2012年天津市公共场所嗜肺军团菌污染状况

目的开展天津市公共场所嗜肺军团菌（简称军团菌）检测,了解该地区军团菌污染情况,为预防和控制军团菌病提供科学依据。方法随机抽取天津市大型公共场所水样共279份,进行军团菌分离培养与鉴定。结果采集的279份水样中,32份检出军团菌,空调系统用水检出率为15．23％,生活类用水检出率为2．44％。其中空调系统用水中冷却水污染最为严重（21．09％）。结论天津市公共场所中存在军团菌污染,对人群存在潜在健康风险,尤其是空调系统冷却水的污染最为严重,应注重加强天津市公共场所集中空调系统的日常监督和预防控制工作,同时深入开展清洗消毒效果评价。     

我国现役军人军团病菌自然感染状况的研究

本文在不同季节用PHA法调查了我国655名不同作业的现役军人血清抗-LDB₁型自然分布及既往呼吸道疾病史,其阳性率高达17.4%。四组不同作业军人阳性分布无统计学差异(P﹥0.25),但冬春季阳性率明显高于夏季(P<0.005)。抗-LDB₁型效价平均值冬春季分别是夏季的4倍和1.61倍,血清IgA含量水平与抗-LDB₁型阳性分布呈平行增高(P<0.005),但与IgG、IgM和ANF、RF、LTT、EaRFc、EtRFc无统计学相关关系。6个月到3年内呼吸道感染史与抗-LDB₁型阳性分布无统计学相关关系(P=0.25)、亚热带出生的军人比寒带出生军人抗-LDB₁型阳性率明显增高(t=6.314)。     

从外环境分离军团杆菌的研究

我们通过腹腔注射嗜肺军团杆菌(Lp)感染豚鼠证明,感染后第4～5天剖杀取脾和肺脏新鲜切面压印于BCYE_α培养基是再分离Lp的最佳条件,又比较了离心和钾明矾絮凝两种集菌法对再分离Lp的影响,结果发现后者分离效果好。从而摸索出从外环境分离军团杆菌的合适程序：钾明矾絮凝-豚鼠-BCYE_α培养基。为了验证此法的实际应用价值,我们从北京某两宾馆空调系统采集水样29份,分离出6株Lp,说明这一方法是可行的。     

双歧杆菌计数培养基研究

目的：选择一种适用于微生态制剂中的双歧杆菌计数培养基。方法：用改良BBL、MRS、改良TJA等选择性培养基和平板厌氧胶法对双歧杆菌进行检测，同时观察双歧杆菌和乳酸酐菌在三种培养基上生长情况。结果：在改良BBL培养基上双歧杆菌生长良好，乳酸酐菌不生长。结论：该培养基用于微生态制剂中双歧杆菌计数操作简便，有效，易于推广。     

嗜肺军团菌的研究进展(一)

军团菌（Legionella）是引起军团病（legionnaires disease，LD）的病原菌，是兼性胞内寄生菌，系革兰氏阴性杆菌。是由于1976年在美国费城退伍军人年会中首次发现的急性发热性肺部疾病而被命名的。广泛存在于自然界，在土壤和水中可以长期存活，自来水中可以存活1年以上。军团菌主要寄生在水中的原生动物体内，尤其是30℃～40℃热水系统为军团菌提供了一个非常良好的孳生环境，对人体健康造成很大的威胁。在建筑给水系统中，特别是封闭的公共卫生场所检出率高。国内自1983年康晓明首次报道该病以来，有关的研究报告不断增加，特别是近几年，全国十几个省市都有病例报告。目前已知军团菌有45种64个血清型，能引起人类疾病的约有20种，常见的有嗜肺军团菌（legionella pneumophila，LP）、麦氏军团菌、长滩军团菌、博氏军团菌、菲氏军团菌、杜氏军团菌等，其中嗜肺军团菌是引起流行性、散发性社区获得性肺炎和医院内获得性肺炎的重要病原菌。嗜肺军团菌有15个血清型，都有致病性。其中1型在人军团菌肺炎中最常见，估计70％～90％的军团菌病是由1型嗜肺军团菌引起的。     

嗜肺军团菌的研究进展(二)

3 嗜肺军团菌的敏感药物与抑制剂的研究进展 3．1临床治疗方面到目前为止，临床上对嗜肺军团菌的治疗仍然以红霉素为主。嗜肺军团菌对其他类型的抗生素多不敏感。1996年John研究了嗜肺军团菌对3种大环内酯类药物（erythromycin，甲基红霉素clarithromycin和阿齐红霉素azithromycin）的敏感性，他们试验了5种嗜肺军团菌菌株，发现3种受试药物都能有效抑制这几种嗜肺军团菌菌株在细胞内的生长。     

中央空调冷却塔水中嗜肺军团菌的调查

目的：了解医院、宾馆空调冷却塔水中军团菌污染情况。方法：于2001年8月采集W市2家宾馆和4家医院的中央空调冷却塔水样，过滤空调冷却水的滤膜经盐酸处理后其处理液接种于GVPC平板，烛缸培养后选取可疑菌落进行生化试验、血清学试验并以PCR方法鉴定。结果：W市2家医院及1家星级宾馆的中央空调冷却塔水中分离到5株军团菌，2株为嗜肺军团菌血清1型（Lp1），2株为嗜肺军团菌血清5型（Lp5）。结论：应加强对医院、宾馆空调冷却塔水中军团菌的监测。     

Isolation of Legionella pneumophila from hotels of Greece

Twenty water samples collected from 6 hotels situated in various areas of Greece were examined for the presence of Legionella pneumophila and Legionella-like organisms. Five of the six hotels included in this investigation were associated with cases of legionellosis. Legionella pneumophila serogroups 1 and 8 were isolated from four of six hotels, mainly from the hot water supply system. This is the first isolation and identification of L. pneumophila in Greece.Corresponding author.     

Disconnecting central hot water and using electric showers to avoid colonization of the water system by Legionella pneumophila: an 11-year study

Legionella spp. can be difficult to control in hospitals. The objective of this study was to describe an 11-year experience with the use of electric showers in the control of Legionella pneumophila. From June 1989 to March 1990 there was an outbreak of pneumonia caused by L. pneumophila in a 20-bed renal transplant unit in a university-associated tertiary-care hospital. Control measures included hyperchlorination, heating and flushing of the water system with limited results. In November 1993 the central hot water was disconnected and water for bathing was heated using electric showers. From January 1992 to June 1995 water was collected from showers and water faucets and cultured for L. pneumophila every two weeks. Surveillance cultures were then collected every month until May 1999. During this seven-year surveillance period, 1115 samples of water were cultured. Water cultures were positive on 24 of 429 occasions (without cases of legionellosis) during the pre-shower period (22 months). In the post-shower period (67 months) only one of 686 cultures was positive. Subsequently there have been no new cases of nosocomial pneumonia by L. pneumophila although surveillance continues. In conclusion, disconnecting the central hot water was effective in avoiding colonization of the water system by L. pneumophila. Heating was possible by using electric showers, which are effective, easy to maintain and cheap.     

Isolation of Legionella species/serogroups from water cooling systems compared with potable water systems in Spanish healthcare facilities

Surveillance of Legionella spp. in hospital water systems was performed in forty-four inpatient healthcare facilities in Spain during 2005-2006. A total of 2,341 samples were collected: 470 from cooling systems (cooling towers) and 1,871 from potable water systems. The latter included 211 from cold-water tanks and 260 from hot-water tanks, totalling 471 from central water reservoirs 136 from showers, 1,172 from unfiltered taps and 92 from filtered taps, totalling 1,400 from peripheral points. Temperature, chlorine levels and the presence of Legionella spp. were determined. In all, 373 (15.9%) samples yielded Legionella spp. Significantly higher isolation rates were obtained from cooling towers (23.8%) versus cold- and hot-water tanks (approximately 4.7%), due to the significantly higher number of samples positive for serogroup 1 (19.4 vs 0.9-3.5%). In potable water systems, no differences were found between central water tanks and showers, but significant differences in isolation rates between central water tanks and unfiltered taps were observed (4.7 vs 19.6%) due to differences in non-serogroup 1 L. pneumophila. Filters significantly decreased isolation rates of these serotypes (11 vs 0%). Some seasonal differences were noted, with higher isolation rates in summer for legionella serogroup 1 in cooling systems and for L. pneumophila serogroups 2-14 in potable water systems. In regression models, higher temperatures were associated with colonisation in cooling systems, while lower chlorine levels were associated with colonisation in potable water systems.     

Long-term persistence of a single Legionella pneumophila strain possessing the mip gene in a municipal shower despite repeated cycles of chlorination

The ability of Legionella pneumophila to colonise domestic water systems is a primary cause of outbreaks of Legionnaire's disease in humans. World Health Organization guidelines recommend that drinking water is chlorinated to between 0.2 and 1mg/L [Chlorine in drinking-water. Guidelines for drinking-water quality, 2nd edn. Geneva: World Health Organization; 1996], but L. pneumophila is repeatedly isolated from chlorinated water systems, indicating that this treatment is not effective at preventing colonisation. Current UK guidelines recommend a one-off treatment of 20-50mg/L of free chlorine to remove the bacteria. In this study we report on the persistence of L. pneumophila serogroup 1 in a domestic shower system despite repeated cycles of chlorination at 50mg/L for 1h exposure time, over the course of two and a half years. Persisting isolates were subjected to in-vitro phenotypic analyses and polymerase chain reaction analysis for the toxin-encoding mip gene. Random amplified polymorphic DNA typing was also performed to determine whether the isolates recovered on different occasions were the same strain. We found that seven isolates of L. pneumophila recovered over a two-and-a-half year period are the same genetically defined strain, indicating that the bacteria can persist despite repeated cycles of chlorination after each successive isolation.     

Clinical and environmental distribution of Legionella pneumophila in a university hospital in Italy: efficacy of ultraviolet disinfection

The molecular epidemiology of Legionella pneumophila in the 'V. Monaldi' University Hospital was studied. Seven cases of nosocomial Legionnaires' disease were diagnosed between 1999 and 2003. Two clinical legionella strains obtained from two patients in the adult cardiac surgery unit (CSU) and 30 environmental legionella strains from the paediatric and adult CSUs, neonatal intensive care unit (NICU) and the cardiorespiratory intensive care unit (CR-ICU) were serotyped and genotyped. L. pneumophila serogroup 1/Philadelphia with an identical pulsed-field gel electrophoresis (PFGE) profile A was isolated from two patients in the adult CSU, and from three and one water samples taken in the adult CSU and the paediatric CSU, respectively, from 2001 to 2002. Furthermore, L. pneumophila serogroup 3 with an identical PFGE profile B was identified in 20 environmental strains from all wards, L. pneumophila serogroup 3 with PFGE profile C was identified in a single environmental strain from the CR-ICU, and non-pneumophila Legionella with identical PFGE profile D was identified in five environmental strains from the adult CSU, paediatric CSU and NICU. Ultraviolet irradiation was effective in disinfection of the hospital water supplies in the adult and paediatric CSUs contaminated by L. pneumophila clone associated with nosocomial Legionnaires' disease. In conclusion, these data demonstrate that two cases of nosocomial legionellosis were caused by the persistence of a single clone of L. pneumophila serogroup 1/Philadelphia in the hospital environment, and that disinfection by ultraviolet irradiation may represent an effective measure to prevent nosocomial Legionnaires' disease.     

嗜肺军团菌1~8血清型自然感染的季节性特征的研究

1986年3月~1的7年5月,在芜湖、南京分别用定群研究和重复横断面调査方法分析了嗜肺军团菌1~8型自然感染和传播的季节性特征。结果表明存在明显的夏秋季高峰现象。同时,讨论了造成这种季节性波动流行病学特征的可能生态学机制。     

Evaluation of the protective immunity of the Legionella pneumophila recombinant protein FlaA/MompS/PilE in an A/J mouse model

To investigate the protect effects of the recombinant protein FlaA/MompS/PilE against Legionella pneumophila (L. pneumophila), the coding sequences of the three proteins were optimized by DNA Star software firstly, cloned, expressed by Escherichia coli BL21, and purified. To give an enhanced the immunological response, the proteins were linked together with (Linker) or without a linker insert (NLinker) and were purified from E. coli BL21. The A/J mouse model was used to determine the level of the induction of protective immunity from the purified proteins. Our results showed that the IgG titer, which was measured by ELISA, was increased after the administration of the five proteins. Compared to the administration of the individual proteins, the chimeric Linker and NLinker proteins displayed lasting immunity to a lethal dose of L. pneumophila challenge. The Linker protein protected the A/J mouse against a higher dose of L. pneumonia compared to the other proteins used in this study, as it contained a more effective immunogen. The work presented here demonstrates that the bioinformatics software, DNA Star, is a valid tool to analyse the epitopes of proteins and was useful in the optimization of proteins that could induce the protective immune response to L. pneumophila. The cross-immunity of recombinant proteins, such as the Linker and the NLinker chimera, have higher generates a greater immune than the single proteins.     

儿童急性呼吸道感染肺炎支原体及嗜肺军团菌IgM抗体检测结果分析

目的分析儿童急性呼吸道感染(ARI)者肺炎支原体(MP)及嗜肺军团菌血清1型(LP1)感染情况及流行病学特点。 方法选择2013年1～12月,在四川省妇幼保健院儿科临床诊断为ARI的1 167例患儿为研究对象。采用间接免疫荧光法检测其血清MP及LP1 IgM抗体,统计学比较不同季度、年龄及性别的MP、LP1及MP＋LP1混合感染阳性检出率差异。 结果1 167例ARI患儿中,①MP、LP1及MP＋LP1混合感染的阳性检出率分别为25.0%、7.4%及4.3%。②2013年第二季度MP阳性检出率(36.5%)显著高于第一、三、四季度(21.2%、23.1%、22.6%),且差异均有统计学意义(χ²＝7.57,12.07,13.55;P<0.01);而LP1及MP＋LP1混合感染的阳性检出率在不同季度比较,差异均无统计学意义(χ²＝6.57,5.88;P>0.05)。③不同年龄患儿的MP、LP1及MP＋LP1阳性检出率比较,差异均有统计学意义(χ²＝199.01,35.18,19.89;P<0.01),而且随患儿年龄增长,MP、LP1及MP＋LP1阳性检出率逐渐升高。④女性患儿MP阳性检出率显著高于男性(29.0% vs 22.6%,χ²＝5.88,P<0.05),而不同性别患儿的LP1及MP＋LP1阳性检出率比较,差异则无统计学意义(P>0.05)。 结论ARI患儿有较高MP及LP1阳性检出率,应引起儿科医师高度重视。     

Is pulsed-field gel electrophoresis a valuable tool to identify nosocomial cases of Legionella pneumophila disease?

Pulsed-field gel electrophoresis (PFGE) was used to type Legionella pneumophila isolates collected from the water systems of Besan?on University Hospital and other hospitals in Franche-Comté region between January 2001 and December 2002 and compare them with patient isolates to identify hospital-acquired pneumonia. Genomic DNA was digested with SfiI and subjected to PFGE in a clamped, homogeneous electric field apparatus. Two of 11 Legionella infections were hospital-acquired. Both were with the same type, also present in the ward water. An environmental strain isolated from the water system of Vesoul Hospital, exhibited DNA pattern 6, also found in three patients with community-acquired pneumonia, who had never been in Vesoul hospital and lived in different towns located >60 km away. Patient 11, who lived in Besan?on, was infected with a DNA pattern 12 strain. This patient had never been to the Besan?on swimming pool, from which a similar strain was collected. Subtype matching of patient and environmental isolates should be interpreted with caution, and it is important to combine a molecular typing method with sound epidemiological data to ensure that the most stringent criteria are used to determine whether a hospital-reservoir is responsible for nosocomial pneumonia.     

Influence of sequential cultivation on virulence of Legionella pneumophila and Staphylococcus aureus

Virulence of Legionella pneumophila strain Monza 3 and Staphylococcus aureus strain Smith diffuse was investigated after sequential cultures on nutrient media. L. pneumophila lost its ability to multiply within Acanthamoeba polyphaga after 50 passages on Legionella selective agar, while S. aureus maintained its pathogenicity in the mouse peritonitis model after 100 sequential cultures on tryptic soy agar. These results demonstrate high preservation of virulence in staphylococci in contrast to legionellae. Differentiation of virulent and avirulent phenotypes of legionellae by the protozoal model may be helpful for detecting sources of infection in water hygiene.