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90年代新发现的非结核分枝杆菌 总被引:3,自引:0,他引:3
非结核分枝杆菌自发现以来,平均每10年新发现近20余种,且越来越受重视。将90年代新发现的25种非结核分枝杆菌的研究概况作一综述。 相似文献
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结核分枝杆菌可以在人体内缓慢增殖,释放代谢产物,造成细胞损伤,引起结核病。其致病机制可能与其复杂的细胞壁成分密切相关。结核分枝杆菌细胞壁中的脂质、糖类及蛋白类物质在构成屏障结构,保护并辅助结核分枝杆菌在细胞内的生长及迁移,调节宿主免疫应答,造成宿主组织细胞损伤等方面发挥重要生物学作用。其表达受众多基因的精细调控。本文将对结核分枝杆菌细胞壁中的脂质阿拉伯甘露聚糖和分枝菌酸在其毒力中的作用,以及sig基因对毒力的调节作用作一综述。 相似文献
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城市生活饮用水中非结核分枝杆菌调查 总被引:1,自引:0,他引:1
目的 调查上海市生活饮用水中非结核分枝杆菌的状况及主要菌种分布。方法 应用过滤法收集细菌, 并在改良罗氏培养基上培养; 通过16S rRNA 测序鉴定菌种。结果 上海市生活饮用水中非结核分枝杆菌的检出率为16. 7% , 其中自来水厂原水、出厂水和居民生活饮用终端水的检出率分别为60% 、25% 和10. 3% 。分离鉴定的非结核分枝杆菌菌种为戈登分枝杆菌及偶发分枝杆菌, 分别占90% 及10% 。结论 在上海市居民生活饮用水系统中存在非结核分枝杆菌, 因此, 应当采取有效的控制方法以保护公众的健康。 相似文献
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结核病是当今影响人类健康、流行性最广、病死率最高的感染性疾病之一。结核病的诊断和疫苗的构建成为当前的研究热点,筛选出结核分枝杆菌免疫优势抗原是快速准确的诊断结核病及研制安全有效的疫苗的关键。拟对近年来国内外学者发现的结核分枝杆菌免疫优势抗原的分子生物学特性研究进展进行综述。 相似文献
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结核病当今世界人类致死的主要疾病之一,早期诊断发现病人、选择敏感的抗结核药物进行有效治疗是控制结核病的关键。而临床上对结核病患者检出率低,漏诊率和误诊率高,结果导致结核耐药的情况越来越严重。简便、快速、准确的免疫学检测方法在诊断结核病中起到了重要的作用。本文对用于免疫学检测的蛋白抗原作一综述。 相似文献
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比较硝基苯甲酸/噻吩−2−羧酸肼(PNB/TCH)生长试验、胶体金法、荧光PCR法和基因芯片法用于结核分枝杆菌(MTB)和非结核分枝杆菌(NTM)鉴定的效能,从而为临床选择鉴别MTB和NTM的实验室方法提供参考依据。
收集2021—2022年疑似肺结核患者痰液和肺泡灌洗液样本,选择经BACTEC MGIT 960全自动快速分枝杆菌培养鉴定药敏仪液体培养阳性的440份标本,分别采用PNB/TCH生长试验、胶体金法、荧光PCR法和基因芯片法鉴定MTB和NTM。以16S rRNA基因测序法为金标准,比较4种方法的效能。
440份分枝杆菌阳性标本,16S rRNA基因测序法鉴定出MTB和NTM分别为316株和124株。PNB/TCH生长试验、胶体金法、荧光PCR法和基因芯片法鉴定MTB的敏感度分别为96.5%、97.8%、100.0%和99.7%,差异具有统计学意义(
PNB/TCH生长试验、胶体金法、荧光PCR法和基因芯片法均可用于MTB和NTM鉴定。胶体金法和荧光PCR法鉴定MTB时效性较好,但胶体金法经济、便捷,更适合于基层临床实验室MTB快速鉴定;基因芯片法对软、硬件均有一定要求、检测成本较高,在一定程度上限制了临床的普及应用。
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微量元素对结核分枝杆菌生长的影响 总被引:1,自引:1,他引:0
本文报道了25种微量元素在改良罗氏培养基上对分枝杆菌菌株H,,Ra和BcG生长的促进作用。试验结果表明:N,、B、Mo、Cr、Zn、Se、Be等元素能显著地促进菌株的生长。Sr、Cu,Al、Si等元素也在一定程度上促进菌株的生长。培养基的pH值对微量元素的这种生长促进作用有一定影响。Zn、M。与草酸铵组合,对分枝杆菌菌株H,,Ra和BoG在酸性培养基上的初生长和后生长,均有明显的促进作用。而Co、Cu和Mn组合能部分地消除高pH值对分枝杆菌生长的抑制作用o N,和se有使分枝杆菌斜面培养物保持细胞和菌落完整的作用。 相似文献
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L.H. Leach P. Zhang T.M. LaPara R.M. Hozalski A.K. Camper 《Journal of applied microbiology》2009,107(3):978-988
Aims: To develop a PCR-based tracking method for the detection of a subset of bacteria in drinking water distribution systems capable of degrading haloacetic acids (HAAs).
Methods and Results: Published degenerate PCR primers were used to determine that 54% of tap water samples (7/13) were positive for a deh gene, indicating that drinking water distribution systems may harbour bacteria capable of HAA degradation. As the published primer sets were not sufficiently specific for quantitative PCR, new primers were designed to amplify deh II genes from selected indicator strains. The developed primer sets were effective in directly amplifying deh II genes from enriched consortia samples, and the DNA extracted from tap water provided that an additional nested PCR step for detection of the deh II gene was used.
Conclusions: This study demonstrates that drinking water distribution systems harbour microbes capable of degrading HAAs. In addition, a quantitative PCR method was developed to detect and quantify deh II genes in drinking water systems.
Significance and Impact of the Study: The development of a technique to rapidly screen for the presence of dehalogenase genes in drinking water distribution systems could help water utilities determine if HAA biodegradation is occurring in the distribution system. 相似文献
Methods and Results: Published degenerate PCR primers were used to determine that 54% of tap water samples (7/13) were positive for a deh gene, indicating that drinking water distribution systems may harbour bacteria capable of HAA degradation. As the published primer sets were not sufficiently specific for quantitative PCR, new primers were designed to amplify deh II genes from selected indicator strains. The developed primer sets were effective in directly amplifying deh II genes from enriched consortia samples, and the DNA extracted from tap water provided that an additional nested PCR step for detection of the deh II gene was used.
Conclusions: This study demonstrates that drinking water distribution systems harbour microbes capable of degrading HAAs. In addition, a quantitative PCR method was developed to detect and quantify deh II genes in drinking water systems.
Significance and Impact of the Study: The development of a technique to rapidly screen for the presence of dehalogenase genes in drinking water distribution systems could help water utilities determine if HAA biodegradation is occurring in the distribution system. 相似文献
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Ji-Hyun Shin Hae-Kyung Lee Eun-Jin Cho Jae-Yon Yu Yeon-Ho Kang 《Journal of microbiology (Seoul, Korea)》2008,46(6):608-614
Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and can cause nosocomial infections in immunocompromised
patients. Recently the presence of NTM in public drinking water and hospital water distribution systems has been reported.
Their ability to form biofilms and their resistance to chlorine both contribute to their survival and colonization in water
distribution systems. Here we analyzed thirty-two hospital tap water samples that were collected from different locations
in three hospitals so as to evaluate the prevalence of NTM species. The water samples were concentrated by membrane filtration
and then eluted with sterilized water following sonication. Two-step direct PCR targeting the rpoB gene, restriction fragment length polymorphism (RFLP) using the MspI restriction enzyme, and sequence analysis were performed for identification of NTM to the species level. The sequences of
each PCR product were analyzed using BLASTN. Seven samples (7/32, 21.9%) were positive for NTM as determined by nested-PCR.
The PCR-RFLP results indicated five different patterns among the seven positive PCR samples. The water-born NTM were identified,
including M. peregrinum, M. chelonae (2 cases), M. abscessus, M. gordonae (2 cases), and Mycobacterium sp. JLS. The direct two-step PCR-RFLP method targeting the rpoB gene was effective for the detection and the differentiation of NTM species from hospital tap water. 相似文献
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Aims: This study investigated the effects of phosphorus on biofilm formation via annular reactor systems in terms of biofilm cell growth, exopolysaccharide (EPS) production, biofilm structure and cell metabolic potential.
Methods and Results: Drinking water biofilms were developed in annular reactors with supplement of carbon and different levels of phosphorus. The biofilm formation was monitored over a period of 30 days. Biofilm related parameters were examined by various methods, which included heterotrophic plate count, total carbohydrate content, confocal laser scanning microscopy and GN2 microplate assay. Our results showed that phosphorus addition can promote the biofilm cell growth (cell count increased about 1 log with addition of 30 and 300 μg l−1 of phosphorus). However, the addition of 30 and 300 μg l−1 of phosphorus caused 81% and 77% decrease in EPS production, respectively. The results of biofilm structure analysis showed that the addition of 30 and 300 μg l−1 of phosphorus can induce thicker and less homogeneous biofilms with more biomass. Furthermore, the addition of 30 and 300 μg l−1 of phosphorus dramatically increased the biofilm cell metabolic potential. The addition of 3 μg l−1 of phosphorus was found to have minor effects on the parameters examined.
Conclusions: The results indicate phosphorus addition to drinking water distribution system (DWDS) has a complicated effect on the biofilm formation.
Significance and Impact of the Study: As the addition of phosphorus at certain levels can affect the biofilm growth in DWDS, care should be taken when phosphate-based corrosion inhibitors are used in the DWDS. 相似文献
Methods and Results: Drinking water biofilms were developed in annular reactors with supplement of carbon and different levels of phosphorus. The biofilm formation was monitored over a period of 30 days. Biofilm related parameters were examined by various methods, which included heterotrophic plate count, total carbohydrate content, confocal laser scanning microscopy and GN2 microplate assay. Our results showed that phosphorus addition can promote the biofilm cell growth (cell count increased about 1 log with addition of 30 and 300 μg l
Conclusions: The results indicate phosphorus addition to drinking water distribution system (DWDS) has a complicated effect on the biofilm formation.
Significance and Impact of the Study: As the addition of phosphorus at certain levels can affect the biofilm growth in DWDS, care should be taken when phosphate-based corrosion inhibitors are used in the DWDS. 相似文献
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Although health risk due to discoloured water is minimal, such water continues to be the source of one of the major complaints received by most water utilities in Australia. Elevated levels of iron (Fe) and/or manganese (Mn) in bulk water are associated with discoloured water incidents. The accumulation of these two elements in distribution systems is believed to be one of the main causes for such elevated levels. An investigation into the contribution of pipe wall biofilms towards Fe and Mn deposition, and discoloured water events is reported in this study. Eight laboratory-scale reactors were operated to test four different conditions in duplicate. Four reactors were exposed to low Fe (0.05?mg?l?1) and Mn (0.02?mg?l?1) concentrations and the remaining four were exposed to a higher (0.3 and 0.4?mg?l?1 for Fe and Mn, respectively) concentration. Two of the four reactors which received low and high Fe and Mn concentrations were chlorinated (3.0?mg?l?1 of chlorine). The biological activity (measured in terms of ATP) on the glass rings in these reactors was very low (~1.5 ng cm?2 ring). Higher concentrations of Fe and Mn in bulk water and active biofilms resulted in increased deposition of Fe and Mn on the glass rings. Moreover, with an increase in biological activity, an increase in Fe and Mn deposition was observed. The observations in the laboratory-scale experiments were in line with the results of field observations that were carried out using biofilm monitors. The field data additionally demonstrated the effect of seasons, where increased biofilm activities observed on pipe wall biofilms during late summer and early autumn were found to be associated with increased deposition of Fe and Mn. In contrast, during the cooler months, biofilm activities were a magnitude lower and the deposited metal concentrations were also significantly less (ie a drop of 68% for Fe and 86% for Mn). Based on the laboratory-scale investigations, detachment of pipe wall biofilms due to cell death or flow dynamics could release the entrapped Fe and Mn into the bulk water, which could lead to a discoloured water event. Hence, managing biofilm growth on drinking water pipelines should be considered by water utilities to minimize accumulation of Fe and Mn in distribution networks. 相似文献
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M. Kitajima Y. Tohya K. Matsubara E. Haramoto E. Utagawa H. Katayama 《Letters in applied microbiology》2010,51(1):119-121
Aims: To evaluate the reduction of human norovirus (HuNoV) by chlorine disinfection under typical drinking water treatment conditions. Methods and Results: HuNoV, murine norovirus (MNV) and poliovirus type 1 (PV1) were inoculated into treated water before chlorination, collected from a drinking water treatment plant, and bench‐scale free chlorine disinfection experiments were performed for two initial free chlorine concentrations, 0·1 and 0·5 mg l?1. Inactivation of MNV reached more than 4 log10 after 120 and 0·5 min contact time to chlorine at the initial free chlorine concentrations of 0·1 and 0·5 mg l?1, respectively. Conclusions: MNV was inactivated faster than PV1, and there was no significant difference in the viral RNA reduction rate between HuNoV and MNV. The results suggest that appropriate water treatment process with chlorination can manage the risk of HuNoV infection via drinking water supply systems. Significance and Impact of the Study: The data obtained in this study would be useful for assessing or managing the risk of HuNoV infections from drinking water exposure. 相似文献
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Distribution of six virulence factors in Aeromonas species isolated from US drinking water utilities: a PCR identification 总被引:1,自引:0,他引:1
AIMS: To examine whether Aeromonas bacteria isolated from municipally treated water had virulence factor genes. METHODS AND RESULTS: A polymerase chain reaction-based genetic characterization determined the presence of six virulence factors genes, elastase (ahyB), lipase (pla/lip/lipH3/alp-1) flagella A and B (flaA and flaB), the enterotoxins, act, alt and ast, in these isolates. New primer sets were designed for all the target genes, except for act. The genes were present in 88% (ahyB), 88% (lip), 59% (fla), 43% (alt), 70% (act) and 30% (ast) of the strains, respectively. Of the 205 isolates tested only one isolate had all the virulence genes. There was a variety of combinations of virulence factors within different strains of the same species. However, a dominant strain having the same set of virulence factors, was usually isolated from any given tap in different rounds of sampling from a single tap. CONCLUSIONS: These results show that Aeromonas bacteria found in drinking water possess a wide variety of virulence-related genes and suggest the importance of examining as many isolates as possible in order to better understand the health risk these bacteria may present. SIGNIFICANCE AND IMPACT OF THE STUDY: This study presents a rapid method for characterizing the virulence factors of Aeromonas bacteria and suggests that municipally treated drinking water is a source of potentially pathogenic Aeromonas bacteria. 相似文献