TB PCR in the early diagnosis of tuberculous meningitis: evaluation of the Roche semi-automated COBAS Amplicor MTB test with reference to the manual Amplicor MTB PCR test. .

SETTING: Cecilia Makiwane Hospital, Mdantsane, Eastern Cape, Republic of South Africa. OBJECTIVE: To assess the role of the semi-automated Roche COBAS AMPLICOR(TM)Mycobacterium tuberculosis PCR test in the diagnosis of tuberculous meningitis (TBM). DESIGN: Eighty-three specimens of cerebrospinal fluid (CSF) were collected prospectively from 69 patients with suspected TBM. The COBAS AMPLICOR TB PCR test was compared with the manual AMPLICOR(TM)TB PCR test, clinical and cerebrospinal fluid (CSF) findings, direct ZN smear and radiometric TB culture. RESULTS: CSF from 7/40 (17.5%) patients treated for TBM were positive by TB COBAS AMPLICOR(TM). The sensitivity of the test was not significantly different (p=0.375) from the manual TB AMPLICOR(TM)PCR test. The comparative sensitivities of the TB COBAS AMPLICOR(TM)PCR and the manual AMPLICOR PCR for detecting cases of definite and probable TBM from CSF collected within 9 days of commencing antituberculosis treatment were 40% and 60% respectively. All 29 patients not treated for TBM were negative by COBAS AMPLICOR(TM), giving a specificity of 100%. CONCLUSION: The COBAS AMPLICOR(TM)TB PCR test is a rapid and highly specific diagnostic test for TBM. However, there was a non-significant trend favouring slightly greater sensitivity using the manual AMPLICOR(TM)TB PCR test.     

Rapid molecular diagnosis of tuberculous meningitis using the Gen-probe Amplified Mycobacterium Tuberculosis direct test in a large Canadian public health laboratory.

OBJECTIVE: A 5-year retrospective study of the performance of the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (MTD) for detecting Mycobacterium tuberculosis complex in cerebrospinal fluid (CSF). Patient data from culture-confirmed cases of tuberculous meningitis (TBM) were also analysed. RESULTS: In total, 311 CSF specimens were tested by the MTD, of which 17 were positive. When compared with culture (gold standard), the sensitivity and specificity of the MTD test were 93.8% and 99.3%, respectively. The positive and negative predictive values for TBM were 88.2%, and 99.7%. Clinical and epidemiological information was requested for all culture-positive TBM patients. These data were used to assess the mortality rate (55.6%) and to determine common factors that could be applied as selection criteria for the appropriate testing of CSF by MTD. CONCLUSION: The study found the MTD test to be a rapid, sensitive and specific test for TBM. A history of immigration from an area endemic for tuberculosis (TB), a history of TB, symptoms of neurological deficits and the results of CSF analyses could be used to appropriately select CSF for MTD testing in order to provide a critical early diagnosis of TBM.     

荧光定量PCR技术对前驱期小儿结核性脑膜炎的应用价值

目的 了解荧光定量PCR（FQ-PCR）技术对前驱期（早期）小儿结核性脑膜炎（简称“结脑”）的快速诊断、疗效观察和预后判断的作用和意义。方法 选择被金标准（快速Mtb培养）确诊未经抗结核治疗的117例前驱期结脑组患儿和排除结脑的30例对照组患儿脑脊液标本,数字表法随机编号进行FQ-PCR检测Mtb DNA,计算其敏感度、特异度、诊断指数、阳性预测值、阴性预测值、符合率等统计指标并进行分析;治疗3周后结脑组盲法行培养和FQ-PCR检测,计算二者阳性检出率;随访出院时两种方法检测为阴性的结脑组患儿2年后各自复发率,进行统计学分析。结果 初诊患儿FQ-PCR检测结果与金标准比较敏感度、特异度、符合率为100.0%（117/117）、96.7%（29/30）、99.3%（146/147）,诊断指数达196.7%,经卡方检验,两者差异无统计学意义（χ²=0.000,P=1.000）,相关性分析r=0.9790,两种方法间有相关性（χ²=140.9,P=0.000）。结脑组治疗3周后培养法和FQ-PCR法阳性检出率分别为27.35%（32/117）和58.12%(68/117),两者差异有统计学意义（χ²=22.63,P=0.000）;随访结脑组患儿出院时两种方法检测阴性2年后复发结果为：78例培养法阴性患儿复发7例（8.97%）,69例FQ-PCR检测阴性患儿未见复发患者,差异有统计学意义（χ²=4.6736,P=0.0306）。结论 FQ-PCR检测脑脊液TB-DNA,准确、简便、快速,有助于早期诊断结脑,对疗效监测和预后评估比培养法更具优势。     

Broad-range real time PCR and DNA sequencing for the diagnosis of bacterial meningitis

Rapid aetiological diagnosis of bacterial meningitis is crucial for the early targeting of antimicrobial and adjuvant therapy. Broad-range polymerase chain reaction (PCR) targeting the 16S rRNA gene allows aetiological diagnosis of bacterial meningitis when applied to cerebrospinal fluid (CSF). We assessed the additional diagnostic effect of applying a novel broad-range real time PCR and subsequent DNA sequencing to culture, microscopy, and broad-range conventional PCR on CSF in patients with suspected bacterial meningitis. Broad-range conventional PCR and broad-range real time PCR with subsequent DNA sequencing were applied to 206 CSF specimens collected consecutively from 203 patients aged 6 d to 86 y. Patients' charts were reviewed for clinical information. 17 pathogens were identified by PCR and DNA sequencing or culture. Three specimens were negative by culture but positive by broad-range real time PCR. Three specimens were positive by culture but negative by broad-range real time PCR. Compared with culture, the sensitivity of broad-range real time PCR was 86%, and the specificity 98%. Conventional PCR resulted in a sensitivity of 64% and specificity of 98%. Broad-range real time PCR was generally comparable to culture of CSF and may be a useful supplement, particularly when antimicrobial therapy has been administered. Broad-range real time PCR was more sensitive than broad-range conventional PCR and microscopy.     

Diagnosis of tuberculous meningitis: clinical and laboratory parameters.

BACKGROUND: Confirming the clinical suspicion of tuberculous meningitis (TBM) has always been problematic. Whilst smear and culture positivity are diagnostic, these tests have low sensitivity. The polymerase chain reaction (PCR) assay has given variable results. AIM: This study attempted to improve the diagnostic yield by: (a) increasing the cerebrospinal fluid (CSF) volumes; (b) testing the yield from three specimens of CSF assumed to represent lumbar, cervico-thoracic cord, and base of brain CSF samples; (c) undertaking PCR assays using multiple primer sets; and (d) using real-time PCR. METHOD: Patients suspected of having cranial or spinal meningeal tuberculosis were entered into the study. Three aliquots of CSF were subjected to smear, culture, and conventional and real-time PCR. Three sets of primers - IS6110, MPB64, and PT8/9 - were used. Patients were retrospectively classified into four categories: 'definite TB' (culture positive), 'probable TB' (clinical and other tests suggestive of TB), 'not TB', and 'uncertain diagnosis'. RESULTS: A total of 68 patients were studied. There were 20 patients classified as definite TB, 24 probable TB, 17 not TB, and seven uncertain diagnosis. Forty-eight of 57 (84.2%) patients tested were HIV seropositive. The IS6110 PCR was positive in 27 patients which included 18/20 culture positive cases, six in the probable TB group, and three in the not TB group. The MPB64 and PT8/9 primers did not increase the yield. Real-time PCR was positive in seven additional patients. Combining the definite and probable TB, the sensitivity of all PCR assays was 70.5% (31/44) and specificity 87.5% (21/24). CONCLUSION: Targeting multiple sites of the TB genome using conventional PCR did not increase the number of positive cases. Real-time PCR was more sensitive. However, all the current techniques are still too insensitive to confidently exclude the diagnosis on laboratory grounds.     

抗酸染色全自动显微扫描识别系统的临床应用评价

目的 评价抗酸染色全自动显微扫描系统(AFB-AS)检测肺结核患者痰液标本应用价值。方法 搜集2019年1月至8月于北京结核病控制研究所确诊的462例肺结核患者作为研究对象,每例患者留取3份初诊痰液标本,共计1386份。所有标本均完成萋-尼抗酸染色,采用双盲法使用传统抗酸杆菌染色镜检和AFB-AS检查;每例患者选取2份痰液标本进行分枝杆菌分离培养,共计完成924份;其中1份同时进行GeneXpert MTB/RIF(简称“Xpert”)检测,共计完成462份。比较不同方法检测肺结核患者痰标本结果;以分枝杆菌分离培养结果为参照,分析传统抗酸杆菌染色镜检和AFB-AS检测肺结核患者痰标本的效能;分析传统抗酸杆菌染色镜检和AFB-AS检测均为阳性结果的等级相关性。结果 各方法检测肺结核患者痰标本阳性率从高到低依次为Xpert(69.26%,320/462)、分枝杆菌分离培养(43.61%,403/924)、AFB-AS(43.22%,599/1386)、传统抗酸杆菌染色镜检(38.24%,530/1386)。AFB-AS检测痰标本阳性率明显高于传统抗酸杆菌染色镜检,差异有统计学意义(χ²=67.015,P<0.01)。AFB-AS与传统抗酸杆菌染色镜检判读阳性结果等级的相关系数为0.954。以分枝杆菌分离培养结果为参照,AFB-AS检查肺结核患者痰标本敏感度为94.29%(380/403)、特异度为90.40%(471/521)、阳性预测值为88.37%(380/430)、阴性预测值为95.34%(471/494),Kappa值为0.841。结论 AFB-AS检测肺结核患者痰液标本具有较好的应用价值,检验性能能够满足实施萋-尼抗酸染色查找抗酸杆菌项目的要求。     

A reevaluation of sputum microscopy and culture in the diagnosis of pulmonary tuberculosis

This prospective study was undertaken to determine the interpretation of "scanty-positive" acid-fast bacilli on microscopy and to reevaluate simultaneous microscopy and culture of sputum for the accurate diagnosis of pulmonary tuberculosis (PTB). A total of 2,560 specimens were processed from 727 patients. There were 435 positive specimens (17.0 percent), originating from 139 patients, 10 by microscopy only, 176 by culture only, and 249 on both microscopy and culture. Review of the hospital records showed that 107 patients had PTB, 1 had Mycobacterium kansasii colonization, and 31 were thought not to have PTB. Sensitivity and specificity were 53.1 and 99.8 percent for microscopy, 81.5 and 98.4 percent for culture, and 77.6 and 100 percent for microscopy and culture, respectively. Seventy-five microscopy specimens (46 patients) were reported as scanty-positive, of which five (four patients) were deemed false positives, yielding a positive predictive value of 93.3 percent. In those patients with positive sputum microscopy, acid-fast bacilli were detected in one of the first four specimens. Seven isolates (three patients) were mycobacteria other than tubercle (0.27 percent of specimens and 1.6 percent of mycobacteria cultured). Despite the ready availability of laboratory evidence of disease, only 73 percent of cases were diagnosed by ward staff and 36 percent notified by the primary physician. Eleven patients (10.3 percent) died, six of whom had not received diagnoses of PTB before death. Sputum microscopy and culture remains reliable despite Bayesian predictions when applied to a population with a decreasing incidence of tuberculosis.     

Diagnosis of human cytomegalovirus central nervous system disease in AIDS patients by DNA amplification from cerebrospinal fluid.

The utility of amplification of human cytomegalovirus (HCMV) DNA in cerebrospinal fluid (CSF) for the diagnosis of HCMV central nervous system (CNS) disease in AIDS patients was studied. CSF specimens from 30 patients with neurologic dysfunction were assayed by polymerase chain reaction (PCR), and the results were correlated with histopathologic findings, CSF culture, and clinical manifestations. PCR was positive in all 11 patients who had histopathologic evidence of HCMV CNS disease, including 4 who were CSF culture-negative. Three patients with HCMV polyradiculopathy had CSF positive by PCR. Nine patients negative for HCMV by neuropathologic study and an additional 7 patients with HCMV-unrelated clinical diagnosis were all CSF PCR-negative, despite concomitant systemic HCMV infection in 7. In addition, 24 asymptomatic human immunodeficiency virus-infected individuals were CSF PCR-negative. CSF PCR appears to be a sensitive and specific diagnostic method for detection of HCMV CNS disease in AIDS patients.     

Correlation between culture of Mycobacterium tuberculosis and IgG antibody to Mycobacterium tuberculosis antigen-5 in the cerebrospinal fluid of patients with tuberculous meningitis

A retrospective study was made of the correlation between culture of Mycobacterium tuberculosis and detection of IgG antibody to M. tuberculosis antigen-5 in cerebrospinal fluid (CSF) by means of an enzyme linked immunosorbent assay (ELISA). Mycobacterium tuberculosis was cultured from the CSF in 14 of 70 patients with a clinical diagnosis of tuberculous meningitis (TBM). IgG antibody to M. tuberculosis antigen-5 was demonstrated in significant titres (80-640) in all 14 culture-positive patients. Thus, positive correlation was observed between culture of M. tuberculosis and detection of IgG antibody in the CSF. As a result of this observation, the CSF from 56 culture-negative patients with a clinical diagnosis TBM was specifically investigated for the detection of IgG antibody to M. tuberculosis antigen-5 and the findings were correlated with those of culture-positive patients. The assay was positive in 34 of 56 patients, the antibody titre ranging between 80 and 640. In the CSF of 70 patients with non-tuberculous neurological diseases, the assay was negative at a dilution of 1 in 80. Thus, detection of IgG antibody to M. tuberculosis antigen-5 by indirect ELISA carried 100% specificity and 60.7% sensitivity for a tuberculous aetiology in culture-negative patients with TBM. The results of this study suggest that indirect ELISA for IgG antibody to M. tuberculosis antigen-5 in CSF holds definite promise in diagnosis of TBM, particularly when repeated cultures of CSF are negative for M. tuberculosis.     

Diagnostic utility of cerebrospinal fluid studies in patients with clinically suspected tuberculous meningitis.

OBJECTIVE: To compare yields of cerebrospinal fluid (CSF) studies in the diagnosis of tuberculosis meningitis (TBM). DESIGN: Prospective laboratory study, Kenyatta National Hospital, Kenya. STUDY POPULATION: Consecutive patients with 1) headache, neck stiffness and altered consciousness for more than 14 days, 2) above features plus evidence of tuberculosis elsewhere in the body, and 3) on standard antimeningitic drugs for one week without response, were included. Those with contraindications to lumbar puncture, confirmed causes of meningitis (except TB) and on anti-tuberculosis treatment were excluded. METHODS: CSF cell counts, glucose and protein were assayed. CSF was stained on ZN, cultured on LJ and BACTEC and subjected to PCR and LCR for Mycobacterium tuberculosis DNA sequences. Positive tests for M. tuberculosis were classified as definite and the rest as probable TBM. RESULTS: Fifty-eight patients with a mean age of 33.0 years were recruited. Mean CSF cell count was 71/microl and CSF lymphocyte count up 67%. Mean CFS protein and glucose were 2.10 g/l and 2.05 mmol/l, respectively. BACTEC was positive in 20 cases, LJ 12, LCR eight, and PCR and ZN one each. Twenty-six patients had definite and 32 probable TBM. Patients with definite TBM had significantly higher CSF protein, lower CSF glucose, higher CSF cell count and lower CSF lymphocytes. CONCLUSION: TBM can be confirmed in half of clinically suspected cases. More sensitive tests for confirmation of TBM are required.     

结核性脑膜炎评分系统对儿童结核性脑膜炎的诊断价值

目的 评价结核性脑膜炎(TBM)评分系统对儿童TBM与病毒性脑炎进行鉴别的价值。方法 回顾性分析2010年1月1日至2017年12月31日天津市儿童医院呼吸科收住院的确诊及临床诊断TBM的患儿102例(TBM组),以及同期病毒性脑炎患儿125例(病毒性脑炎组)。TBM评分系统采用包括临床表现、脑脊液检测结果、影像学表现、肺结核或肺外结核的其他表现进行综合评分来诊断TBM(分值越高,越支持TBM诊断;评分≥12分可以临床诊断TBM)。采用病例对照研究的方法,比较该评分系统诊断TBM的敏感度及特异度;同时比较该评分系统与结核菌素皮肤试验(TST)、γ干扰素释放试验(IGRA)及脑脊液病原学检测敏感度的差异。结果 TBM组患儿中,16例(15.69%,16/102)脑脊液病原学检测阳性,确诊为TBM患儿;其余86例(84.31%,86/102)TBM患儿经评分系统评估,分值为(13.25±2.22)分,明显高于病毒性脑炎组患儿的评分[(3.79±2.48)分],差异有统计学意义(t=29.97,P<0.001)。86例患儿中,76例患儿TBM评分≥12分,判断为临床诊断TBM患儿;TBM诊断的敏感度为90.20%(92/102),特异度为100.00%(102/102)。脑脊液病原学检查中,抗酸杆菌染色的敏感度为15.69%(16/102),结核分枝杆菌培养的敏感度为10.78%(11/102),DNA检测的敏感度为16.47%(14/85),均明显低于TBM评分系统(χ ²值分别为113.65、128.66、100.64,P值均<0.001)。免疫学检查方法中,TST的敏感度为50.00%(51/102),特异度为99.20%(124/125);IGRA的敏感度为72.55%(74/102),特异度为99.20%(124/125);敏感度均明显低于TBM评分系统(χ ²值分别为39.31、10.48,P值均<0.001)。 结论 TBM评分系统对TBM诊断价值较好,其敏感度明显高于脑脊液抗酸染色、脑脊液结核分枝杆菌培养、脑脊液DNA检测、TST及IGRA等检测方法。     

Correlation between culture of Mycobacterium tuberculosis and IgG antibody to Mycobacterium tuberculosis antigen-5 in the cerebrospinal fluid of patients with tuberculous meningitis

A retrospective study was made of the correlation between culture of Mycobacterium tuberculosis and detection of IgG antibody to M. tuberculosis antigen-5 in cerebrospinal fluid (CSF) by means of an enzyme linked immunosorbent assay (ELISA). Mycobacterium tuberculosis was cultured from the CSF in 14 of 70 patients with a clinical diagnosis of tuberculous meningitis (TBM). IgG antibody to M. tuberculosis antigen-5 was demonstrated in significant titres (80–640) in all 14 culture-positive patients. Thus, positive correlation was observed between culture of M. tuberculosis and detection of IgG antibody in the CSF. As a result of this observation, the CSF from 56 culture-negative patients with a clinical diagnosis TBM was specifically investigated for the detection of IgG antibody to M. tuberculosis antigen-5 and the findings were correlated with those of culture-positive patients. The assay was positive in 34 of 56 patients, the antibody titre ranging between 80 and 640. In the CSF of 70 patients with non-tuberculous neurological diseases, the assay was negative at a dilution of 1 in 80. Thus, detection of IgG antibody to M. tuberculosis antigen-5 by indirect ELISA carried 100% specificity and 60·7 % sensitivity for a tuberculous aetiology in culture-negative patients with TBM. The results of this study suggest that indirect ELISA for IgG antibody to M. tuberculosis antigen-5 in CSF holds definite promise in diagnosis of TBM, particularly when repeated cultures of CSF are negative for M. tuberculosis.     

术后标本行分子生物学检测对结核病患者诊疗的价值

目的 初步探讨分子生物学检测技术在结核病患者术后快速诊断中的价值。方法 回顾性分析2015年1月至2018年2月期间在上海市公共卫生临床中心胸外科接受手术治疗、临床资料齐全的170例结核病患者。170例患者中,男100例(58.82%)、女70例(41.18%); 1~18岁年龄组18例(10.59%)、19~65岁年龄组142例(83.53%)、66~82岁年龄组10例(5.88%);肺结核39例(22.94%)、肺外结核131例(77.06%)。取术后标本采用PCR膜条杂交及二代测序技术的分子生物学方法进行菌种鉴定和耐药相关基因检测。所有患者术前进行晨痰及穿刺活检,或者术中取样进行抗酸染色涂片检测。在进行痰涂片的同时,进行分枝杆菌改良罗氏固体培养、BACTEC MGIT 960快速培养及药物敏感性试验(简称“药敏试验”)。结果 (1)痰液抗酸染色阳性率为9.41%(16/170),其中肺结核患者的阳性率为23.08%(9/39), 而穿刺活检或者术中取样(脓液或分泌物等)的抗酸染色阳性率为51.76%(88/170)。(2)分枝杆菌培养阳性率为27.65%(47/170),其中耐药结核病检出率为14.12%(24/170)。(3)术后标本分子生物学菌种鉴定阳性率为51.76%(88/170);PCR膜条杂交显示,7例为NTM,4例培养联合MPB64抗原检测结果显示为NTM,但未鉴定到菌种;3例培养结果为阴性,无法进行MPB64抗原检测。7例标本进行了分子生物学菌种鉴定,1例为瘰疬分枝杆菌、戈登分枝杆菌复合感染,3例为胞内分枝杆菌, 1例为海分枝杆菌, 1例为鸟分枝杆菌,1例为脓肿分枝杆菌。(4)除去7例NTM感染患者,剩余的163例进行了分子生物学耐药基因检测,对一线抗结核药物耐药基因的检出率为54.60%(89/163), 对二线抗结核药物耐药基因的检出率为49.69%(81/163);与培养后药敏试验结果相比,药敏试验阳性的标本中有29.79%(14/47)在分子生物学耐药基因检测时的结果为阴性,而分子生物学耐药基因检测与药敏试验检测结果阳性的一致性为90.00%(27/30);分子生物学耐药基因检测与BACTEC MGIT 960快速培养药敏试验联合判断对耐药结核病的检出率为63.19%(103/163)。结论 分子生物学检测技术在术后标本的快速诊断中具有重要的价值,可区分结核分枝杆菌、非结核分枝杆菌及是否耐药,为结核病患者术后进一步诊治提供重要参考。     

结核性脑膜炎100例临床分析

目的探讨成人结核性脑膜炎的临床特点、脑脊液改变、影像学特点、诊治方法及其转归。方法回顾性分析1982年1月至2003年12月间在北京协和医院确诊或临床诊断为结核性脑膜炎的100例住院患者的临床资料。结果100例结核性脑膜炎患者中,男性49例,女性51例;年龄（31±11）岁。70％为慢性病程（11．1±9．2）周。13例确诊病例,脑脊液结核杆菌培养阳性,或开颅脑活检病理证实为结核性肉芽肿或粟粒样结核;87例为临床诊断病例。临床表现以发热（97％）,头痛（92％）、意识障碍（71％）和脑膜刺激征多见（77％）,44例伴颅神经损害,以动眼神经和外展神经受损为主。35例X线胸片有活动性肺结核表现,肺外活动性结核12例,陈旧性肺结核18例。腰穿示颅内压增高者占86％,脑脊液呈非化脓性改变,白细胞增高以淋巴细胞为主,蛋白质明显增高,葡萄糖显著下降。52例患者头颅影像学有异常发现,脑室扩张、交通性脑积水和脑梗死最常见。全部病例均接受抗结核治疗,9例行侧脑室外引流术。81例患者病情好转,4例因合并开放性肺结核转结核病院治疗,8例自动出院,死亡7例。结论慢性脑膜炎若伴发肺结核或肺外结核者应高度疑诊结核性,鉴别诊断和诊断性抗结核治疗有效有助诊断。脑脊液涂片和（或）培养抗酸杆菌／结核分枝杆菌阳性,以及脑活检为诊断的金标准。早期诊断、早期治疗是改善本病预后的关键。     

两种实验室技术对肺结核患者手术后不同组织标本的检测结果分析

收集2017年6月至2019年1月就诊于安徽医科大学附属省立医院胸外科,获得肺部组织标本的60例疑诊肺结核患者作为研究对象。对比患者肺部组织病理标本GeneXpert MTB/RIF和抗酸染色的检测结果,评估GeneXpert MTB/RIF和抗酸染色对肺结核患者手术组织标本的检测价值。60例患者中,GeneXpert MTB/RIF检测和抗酸染色的阳性检出率分别为46.7%(28/60)和48.3%(29/60)。5例标本抗酸染色呈阳性,GeneXpert MTB/RIF检测呈阴性,通过分枝杆菌菌种鉴定提示均为结核分枝杆菌。两种方法联合检测的阳性检出率为55.0%(33/60),达到"十三五"全国结核病防治规划要求的病原学检出率提高至50%的目标。研究结论认为,GeneXpert MTB/RIF与抗酸染色方法联合检测肺结核患者肺组织标本,阳性率较高,具有一定的临床应用价值。     

Polymerase chain reaction assay for the detection of Helicobacter pylori in gastric biopsy specimens: comparison with culture,rapid urease test,and histopathological tests.

Ulcer recurrence is probably related to residual Helicobacter pylori (H pylori). Histological examination and culture are considered to be the most specific tests. CLO test is a rapid but less specific test, which is usually used as an alternative test to culture. The aim of this study was to investigate the efficiency of a simplified polymerase chain reaction (PCR) assay as a procedure for the diagnosis of gastric H pylori infection of patients. Biopsy specimens were obtained from antral mucosa of 58 patients at endoscopy and submitted to four tests for detection of H pylori. The bacteria were found in 53%, 43%, 48%, and 50% of patients according to the results of PCR, CLO test, culture, and histological examination. Twenty three patients had both negative histology and negative culture and PCR was negative in all of these. Thirteen patients were not classified because only histology or culture was positive and 10 of these had a positive PCR test. When the diagnosis of H pylori was established by agreement with both histology and culture or three positive tests out of four, 29 patients were H pylori positive (28 having had three positive tests and one displaying positive histology and culture), and 26 were negative, and three undetermined. PCR proved the most sensitive and specific test. These results suggest the simplified PCR assay may be a valuable test for the detection of H pylori.     

分子信标荧光定量PCR在肺结核早期诊断及疗效评价中的初步应用

目的探讨分子信标荧光定量PCR在肺结核早期诊断及疗效评价中的应用价值。方法采集2010年3—7月间在彭州市CDC结核病防治所门诊就诊患者的痰标本382份,其中初诊疑似肺结核患者的痰标本305份,肺结核患者随访痰标本77份,用分子信标荧光定量PCR法和抗酸染色法检测Mtb。结果382份痰标本抗酸染色法、分子信标荧光定量PCR法检测总阳性率分别为12.6%(48/382)、42.4%(162/382),分子信标荧光定量PCR法阳性率显著高于抗酸染色法,差异有统计学意义(χ2=74.5,P<0.001)。结论分子信标荧光定量PCR较抗酸染色法具有更高的灵敏度,不仅提高了肺结核早期诊断的检出率,还能间接反映药物疗效,在肺结核防治工作中具有重要意义。     

Use of polymerase chain reaction (PCR) and DNA probe hybridization to determine the Gram reaction of the infecting bacterium in the intraocular fluids of patients with endophthalmitis

OBJECTIVES: To evaluate polymerase chain reaction (PCR) combined with DNA probe hybridization to determine the Gram reaction of the bacterium in intraocular specimens from patients with infectious endophthalmitis. METHODS: Fifty-seven intraocular specimens - 17 aqueous humor (AH) and 40 vitreous fluid (VF) - from 55 patients with clinically diagnosed infectious endophthalmitis and 25 control intraocular specimens from non-infectious ocular disorders (10 AH and 15 VF) were evaluated by microscopy, culture and PCR-DNA probe hybridization to detect the Gram reaction of the bacterium. RESULTS: PCR-DNA probe hybridization was specific and sensitive to detect 30 fg of both gram-positive and gram-negative bacterial DNA. None of the controls showed bacteria by microscopy, culture or PCR. Of the 57 intraocular specimens, conventional microbiological methods could detect a bacterial aetiology in 32 (56.1%), while PCR-DNA probe hybridization could detect 52 (91.2%) specimens. This difference was statistically significant (P= 0.003). In bacteriologically positive specimens, there was absolute correlation of the Gram reaction between the results of smear and culture methods and PCR-DNA probe hybridization. Of the 25 bacteriologically negative specimens, 20 (80%) were positive by PCR-DNA probe hybridization, of which seven (35%) were gram-positive, 12 (60%) gram-negative and one (5%) positive by both. Results of PCR on AH and VF were not significantly different. CONCLUSION: PCR and DNA probe hybridization to determine the Gram reaction of the bacterium in intraocular fluids is a specific and sensitive method in the diagnosis of bacterial endophthalmitis. AH is an ideal specimen for PCR, since its collection is a simple and safe office procedure.     

免疫组织化学及PCR技术在淋巴结结核病理诊断中的应用价值

目的 探讨免疫组织化学(immunohistochemistry,IHC)及PCR技术在淋巴结结核病理学诊断中的应用价值。方法 收集首都医科大学附属北京胸科医院病理科保存的2012年1月至2013年7月之间的48例手术根治切除淋巴结结核患者(结核组)和21例非淋巴结结核患者(非结核组)的石蜡包埋组织标本,分别应用IHC染色、荧光定量PCR和抗酸染色法对标本进行检测,以临床最后诊断为金标准,比较各方法的检测效能。结果 IHC染色、荧光定量PCR及抗酸染色检测的敏感度分别为52.1%(25/48)、60.4%(29/48)及27.1%(13/48);IHC染色和荧光定量PCR检测敏感度均高于抗酸染色,差异均有统计学意义(χ ²值分别为 6.27、10.84,P值分别为0.012、0.001);而IHC染色与荧光定量PCR比较,敏感度差异无统计学意义(χ ²=0.68,P=0.411)。IHC染色、荧光定量PCR及抗酸染色法检测非结核组结果均为阴性,特异度均为100%(21/21)。IHC染色、荧光定量PCR及抗酸染色法的阴性预测值分别为47.7%(21/44)、52.5%(21/40)、37.5%(21/56);符合率分别为66.7%(46/69)、72.5%(50/69)、49.3%(34/69),IHC染色、荧光定量PCR均优于抗酸染色法。 结论 IHC染色、荧光定量PCR与抗酸染色法相比,可提高阳性检出率,在淋巴结结核的病理学诊断中具有良好应用价值。     

Rapid and efficient detection of extra-pulmonary Mycobacterium tuberculosis by PCR analysis.

SETTING: The diagnosis of extra-pulmonary tuberculosis (EPTB) remains an important clinical problem, primarily because of the inadequate sensitivity of conventional bacteriologic methods for detecting Mycobacterium tuberculosis in extra-pulmonary specimens. OBJECTIVE: To evaluate whether a IS6110-based polymerase chain reaction (PCR) method can be utilized to detect M. tuberculosis in non-pulmonary specimens. DESIGN: Specimens from 286 Mexican patients with a presumptive clinical diagnosis of EPTB were prospectively examined by Ziehl-Neelsen staining, mycobacterial culture on L?wenstein-Jensen slants, and by PCR. The DNA for PCR was extracted by the buffer lysis method and phenol-guanidine thiocyanate-chloroform. Primers that amplify a 200 bp fragment from the insertion-like M. tuberculosis sequence element IS6110 were utilized. RESULTS: Our results demonstrate that this PCR method is highly specific (100%) for identifying M. tuberculosis from a variety of specimens including cerebrospinal fluid (CSF), pleural fluid, ascitic fluid, pericardial fluid, urine, and lymph node exudate. Moreover, the sensitivity of PCR for detecting M. tuberculosis in CSF (94%), pleural fluid (94%), ascitic fluid and other extrapulmonary specimens (93%) greatly exceeds the sensitivity of conventional smear and culture methods. CONCLUSION: These results demonstrate that PCR can be a highly specific and sensitive aid in the detection of M. tuberculosis from extra-pulmonary specimens.