1、G试验和GM试验 -真菌检测,马桂伶 2011-3-16,1,真菌感染会带来怎样的后果呢？,Mortality, length of hospitalization, and costs associated with invasive fungal infections in high-risk patients. Menzin J, Meyers JL, Friedman M, Perfect JR, Langston AA, Danna RP, Papadopoulos G. Am J Health Syst Pharm. 2009 Oct 1;66(19):1711-7.,3,4,5,
2、6,7,8,9,G试验和GM试验 -真菌检测,马桂伶 2011-3-16,10,深部真菌,白色念珠菌新型隐球菌曲霉菌毛霉菌,11,传统的检测方法主要为血培养和组织活检，但血培养历时太长，且阳性率较低。近年来，用于检则真菌的抗原、抗体及代谢产物的血清学检查已用于深部真菌感染的实验室检测。 目前的血清学检查主要针对真菌胞壁或胞内成分beta-葡聚糖、甘露糖、烯醇化酶和Cand-Tec抗原等。,12,G试验-（1，3）-D葡聚糖试验,G试验检测的是真菌细胞壁成分(1，3)-D葡聚糖，由于(1，3)-D-葡聚糖仅广泛存在于真菌的细胞壁中，当真菌进入人体血液或深部组织后，经吞噬细胞的吞噬、消化等处理后，
3、(1，3)-D-葡聚糖可从胞壁中释放出来，从而使血液及其它体液中(1，3)-D-葡聚糖含量增高。 当真菌在体内含量减少时，机体免疫可迅速清除(1，3)-D-葡聚糖。 在浅部真菌感染中，(1，3)-D-葡聚糖未被释放出来，故其在体液中的量不增高。,13,20 世纪 90年代初发现, ( 1-3)-beta-D-葡聚糖可特异性激活自鲎变形细胞溶解产物提取的 G 因子, 从而旁路激活鲎试验,此过程称为 G 试验。临床上, 由于深部真菌感染的严重程度常常与血浆多糖的升高水平一致, 故G 试验可协助深部真菌感染的诊断(包括念珠菌感染和曲霉菌感染等) 。,14,GM实验-半乳甘露聚糖试验,甘露糖是目前研究
4、最为广泛的一种抗原, 广泛存在于真菌胞壁中, 是真菌胞壁的重要组成成分.,15,Plasma( 1-3)-beta-D glucan measurement in diagnosis of invasive deep mycosis and fungal febile episodes,目的：探讨( 1-3)-beta-D glucan 在筛查侵袭性真菌感染及 真菌性发热中的价值。方法：检测了 202 例病员标本，以 ( 1-3)-beta-D- 葡聚糖 的血浆浓度20pg/ ml为界值, 41 例 确诊病员(以活 检和培养阳性为标准) ，37 例为阳性, 阳性率为 90%; 59 例其他原因
5、所致发热者全部阴性,阴性率为 100%结论：( 1-3)-beta-D-葡聚糖可用于早期诊断深部真菌感 染, 其缺点是不能定性, 且此法不能检测出隐球菌 感染,可能是因为隐球菌具有厚壁胞膜。,Obayashi T, Yoshida M, Mor i T, et al. Plasma( 1，3)-beta -D glucan measurement in diagnosis of invasive deep mycosis and fungal febile episodes J . Lancet, 1995, 345( 1) : 17-20.,16,17,Karageorgopoulos DM
6、, b-D-Glucan Assay for the Diagnosis of Invasive Fungal Infections: A Meta-analysis , Clinical Infectious Diseases .2011;52(6):75077,18,76.8%,85.3%,19,conclusion,BDG has good diagnostic accuracy for distinguishing proven or probable IFIs from no IFIs. It can be useful in clinical practice, if implem
7、ented in the proper setting.,20,To update the case-fatality rate (CFR) associated with invasive aspergillosis according to underlying conditions, site of infection, and antifungal therapy, data were systematically reviewed and pooled from clinical trials, cohort or case-control studies, and case ser
8、ies of 10 patients with definite or probable aspergillosis. Subjects were 1941 patients described in studies published after 1995 that provided sufficient outcome data; cases included were identified by MEDLINE and EMBASE searches. The main outcome measure was the CFR. Fifty of 222 studies met the i
9、nclusion criteria. The overall CFR was 58%, and the CFR was highest for bone marrow transplant recipients (86.7%). Amphotericin B deoxycholate and lipid formulations of amphotericin B failed to prevent death in one-half to two-thirds of patients. Mortality is high despite improvements in diagnosis a
10、nd despite the advent of newer formulations of amphotericin B. Underlying patient conditions and the site of infection remain important prognostic factors.,Lin SJ, Schranz J, Teutsch SM. Aspergillosis case-fatality rate: systematic review of the literature. Clin Infect Dis .2001; 32: 358366.,21,Chri
11、stopher D , Diagnosis of Invasive Aspergillosis Using aGalactomannan Assay: A Meta-Analysis ,Clinical Infectious Diseases 2006; 42:141727,22,23,0,0.93,0.0.71,0.61,00.89,24,Conclusions,GM test has moderate accuracy for diagnosis of invasive aspergillosis in immunocompromised patients. The test is mor
12、e useful in patients who have hematological malignancy or who have undergone hematopoietic cell transplantation,25,GM试验在非血液病患者真菌检测中的应用,26,27,28,29,conclusion,1 The prevalence of invasive aspergillosis in the group of patients with COPD was 16.13%。2 The 1 ng/ml cut-off showed a higher positive predic
13、tive value (100%) and comparable negative predictive value to the 0.5 ng/ml cut-off. The value of the test in COPD patients yielded similar results.,30,COPD patients may have increased susceptibility tofungal invasive infection for several reasons,(1)structural changes in lung architecture related t
14、o the pulmonary disease;(2) the common use of long-term or repeated short-term steroid treatments as an additional immunosuppressive factor;(3) frequent hospitalisation and antibiotic treatment, leading to exposure to selected fungal pathogens; (4) co-morbidity factors such as alcoholism, diabetes m
15、ellitus or malnutrition.,F. Ader.Invasive pulmonary aspergillosis in chronic obstructive pulmonary disease: an emerging fungal pathogen. Clin Microbiol Infect ,2005; 11: 427429,31,GM试验在COPD合并真菌感染诊断中的应用,32,33,34,conclusion,In COPD patients, invasive pulmonary aspergillosis currently carries a very po
16、or prognosis. Outcome could perhaps be improved by more rapid diagnosis and prompt therapy with voriconazole.,35,重度COPD患者合并侵袭性曲霉菌病的结果？,36,37,38,E,39,GM test result,40,GM test and mortality,41,Group Mortality,All patients IPA group non-IPA group Aspergillus isolated,33.3% (30/90), 73.7% (14/19), 22.5
17、% (16/71), 70.0% (14/20).,42,conclusion,1 The incidence of IPA in the COPD patients admitted to the ICU was 11.1% (19/171)2 serum GM should be tested at least twice a week to achieve early diagnosis of aspergillosis . 3 at least one positive result of two consecutive GM tests appears to be useful in
18、 the diagnosis of IPA in critically ill COPD patients in an ICU. 4 positive serum GM results combined with the isolation of Aspergillus from respiratory samples may be a potential marker of high mortality.,43,G GM 试验的联合应用,44,45,Representative kinetics of BG ( ) and GM ( ) in different patients. (a)
19、Proven IA in a patient with acute myeloid leukemia who responded to treatment with amphotericin B and caspofungin.,46,(b) Proven IA in a patient with chronic lymphocytic leukemia who did not respond to treatment with amphotericin B.,47,(c) False-positive BG results in a patient with multiple myeloma
20、 and no IA.,48,(d) False-positive GM results in a patient with non-Hodgkins lymphoma and no IA.,49,(e) Negative BG and GM results in a patient with acute myeloid leukemia and no IA who was colonized by C. albicans and C. glabrata.,50,(f) Negative BG and GM results in a patient with chronic lymphocyt
21、ic leukemia and no IA who was colonized by C. albicans,51,conclusion,1 The sensitivity, specicity,and positive and negative predictive values for GM and BG were identical, 87.5, 89.6, 70, and 96.3% 2 False-positive reactions occurred at a rate of 10.3% in both tests, but the patients showing false-p
22、ositive results were different in each test. Both tests anticipated the clinical diagnosis, computed tomography abnormalities, and the initiation of antifungal therapy in most patients, but BG tended to become positive earlier than GM. 3 A combination of the two tests improved the specicity (to 100%
23、) and positive predictive value (to 100%) of each individual test without affecting the sensitivity and negative predictive values. BG and GM detection are useful tests for the diagnosis of IA in high-risk hematological patients, and the combination of the two tests was very useful to identify false
24、-positive reactions by each test.,52,总之：G 、GM 试验都可用于侵袭性真菌感染的检测，G试验对念珠菌及曲霉菌都有较好的敏感度，但不能区分出是念珠菌还是曲霉菌感染；GM试验对曲霉菌感染有较好的特异度。联合G GM试验对临床诊断侵袭性曲霉菌病有较好的价值，但这两个试验用于隐球菌检测，缺乏临床证据，GM 试验能否用于念珠菌的检测仍不明确。,53,感谢聆听不妥之处，望批评指正,54,55,Diagnosis,Proven invasive FI Probable invasive FI Possible invasive FI,Histopathologic o
25、r cytopathologic examination showing hyphae from needle aspiration or biopsy specimen with evidence of associated tissue damage; or positive culture result for a sample obtained by sterile procedure from normally sterile and clinically or radiologically abnormal site consistent with infectionAt leas
26、t 1 host factor criterion; 1 microbiological criterion; and 1 major (or 2 minor) clinical criteria from abnormal site consistent with infectionAt least 1 host factor criterion and 1 microbiological or 1 major (or 2 minor) clinical criteria from abnormal site consistent,56,Type of diagnostic criteria
27、-host factors,1 Neutropenia (96 h refractory to appropriate broad-spectrum antibacterial treatment in high-risk patients; 3 body temperature either 38C or 36C and any of the following predisposing conditions: prolonged neutropenia (110 days) in previous 60 days, recent or current use of signicant im
28、munosuppressive agents in previous 30 days, proven or probable invasive FI during previous episode of neutropenia, coexistence of symptomatic AIDS; signs and symptoms indicating graft-versus-host disease, particularly severe (grade 2) or chronic extensive disease; prolonged (13 weeks)use of corticos
29、teroids in previous 60 days.,57,Type of diagnostic criteria -Microbiological criterion,1 Positive result of culture from sputum or bronchoalveolar lavage uid samples; 2 positive result of culture or ndings of cytologic/direct microscopic evaluation from sinus aspirate specimen; 3 positive ndings of
30、cytologic/direct microscopic evaluation from sputum or bronchoalveolar lavage uid samples;4 positive result antigen in specimens of bronchoalveolar lavage uid, CSF, or 2 blood samples;5 positive ndings of cytologic or direct microscopic examination for fungal elements in sterile body uid samples,58,
31、Type of diagnostic criteria-clinical criterion,Clinical Must be related to site of microbiological criteria and temporally related to current episode LRTIMajor Any of the following new inltrates on CT imaging: halo sign, air-crescent sign, or cavity within area of consolidationaMinor Symptoms of LRTI (cough, chest pain, hemoptysis, or dyspnea); physical nding of pleural rub; any new inltrate not fullling major criterion; pleural effusion,59,
