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1.
To investigate the superiority of the Mycobacteria Growth Indicator Tube (MGIT) over Ogawa medium in the detection of acid-fast bacilli (AFB), we surveyed all specimens for AFB culture using Ogawa medium in 1999 and MGIT in 2000. The MGIT method increased the culture-positive rate from 23.1% (Ogawa medium) to 34.5% (p < 0.01). The culture-positive rate in smear-negative specimens was greatly increased (from 9.5% to 16.9%) (p < 0.01). The culture-negative rate in smear-positive specimens was decreased to 19.5% from 27.7% (p < 0.01). More individuals with positive M. tuberculosis cultures were found by the MGIT method than with Ogawa medium. Many more individuals with nontuberculous mycobacteria (NTM), notably those with NTM other than M. avium complex, were detected by the MGIT method than with Ogawa medium. The use of the MGIT method in the clinical laboratory will improve sensitivity in the detection of AFB.  相似文献   

2.
OBJECTIVE: To compare the clinical and radiographic features of pulmonary tuberculosis (PTB) and non-tuberculous mycobacteria (NTM) lung disease in patients with acid-fast bacilli (AFB) positive sputum specimens. DESIGN: The initial clinical and radiographic features of 229 PTB patients were compared with those of 70 patients with NTM lung disease. The most commonly involved organisms in the NTM lung disease cases were Mycobacterium avium complex (n = 38, 54%) and M. abscessus (n = 26, 37%). RESULTS: Clinical and radiographic findings that were more common in patients with NTM lung disease than in PTB patients were: older age (P < 0.001), non-smoker (P < 0.001), history of previous TB treatment (P < 0.001), absence of pleural effusion (P = 0.017), involvement of middle and/or lower lung zones (P = 0.007), and bilateral disease (P = 0.005). Multivariate analysis showed that older age (> or = 40 years), non-smoker, previous TB treatment, absence of pleural effusion and involvement of middle and/or lower lung zones were significant independent predictors for NTM lung disease. CONCLUSIONS: There is considerable overlap in the clinical and radiographic appearances of PTB and NTM lung disease. The isolation and identification of causative organisms are mandatory for a correct diagnosis in patients with AFB-positive sputum specimens.  相似文献   

3.
SETTING: Low sensitivity of acid-fast bacilli (AFB) sputum smears and absence of productive cough are obstacles to the diagnosis of pulmonary tuberculosis (PTB) in hospitals that lack access to bronchoscopy. OBJECTIVES: To evaluate induced sputum, gastric content, blood and urine specimens to improve PTB diagnosis in patients not diagnosed by expectorated sputum AFB smears. DESIGN: Patients admitted to the medical wards of a large public hospital in Gaborone, Botswana, were prospectively enrolled if they had symptoms consistent with PTB, an abnormal chest radiograph, were treated empirically with anti-tuberculosis chemotherapy or had no improvement on antibiotics, and had a non-productive cough or AFB smear-negative sputum. Induced sputum was stained for AFB and Mycobacterium tuberculosis cultures were performed on induced sputum, gastric contents, urine and blood. RESULTS: Of 140 patients meeting the enrollment criteria, 113 (81%) were human immunodeficiency virus (HIV) positive. Fifty-seven (41%) had PTB based on positive cultures from one or more sites, including 48 (84%) from induced sputum, 17 (30%) urine, 13 (23%) gastric contents and 7 (12%) blood. AFB smears were positive in only 18 (32%) culture-proven PTB cases. CONCLUSION: Induced sputum cultures greatly enhanced M. tuberculosis detection in patients with a high prevalence of HIV/AIDS in a hospital without access to bronchoscopy.  相似文献   

4.

Background

In Korea recently, nontuberculous mycobacteria (NTM) have been more frequently isolated in respiratory specimens, while Mycobacterium tuberculosis (MTB) isolations have decreased. The major NTM lung disease species in Korea are M. intracellulare, M. avium, and M. abscessus, whereas M. kansasii is a rare species. This retrospective study was performed to determine if there are region-specific characteristics of lung disease-causing NTM species in Ulsan, a highly industrialized city in Korea.

Methods

Between January 2010 and July 2013, the results of all acid-fast bacilli (AFB) cultures of respiratory specimens performed at Ulsan University Hospital (Ulsan, Korea) were collected. NTM were identified and regional differences of NTM species were compared.

Results

AFB cultures were performed on 33,567 respiratory specimens, obtained from 10,208 patients, during the study period. Further, 10% of the specimens (3,287/33,567) were AFB culture-positive [MTB, 2,288/3,287 (70%); NTM 999/3,287 (30%)]. The proportion of NTM isolations gradually increased between 2010 and 2013, at 25% and 38%, respectively. The most common NTM species was M. intracellulare (356/999, 36%), followed by M. kansasii (295/999, 30%), M. avium (161/999, 16%), M. abscessus (117/999, 12%) and M. fortuitum (39/999, 4%). This trend was maintained throughout the study period.

Conclusions

In Ulsan, NTM isolation from respiratory specimens is increasing, consistent with previous studies performed in Korea. The distribution of respiratory NTM species, however, differed from previous studies that were performed in other regions of Korea: M. kansasii was the second most common NTM species in Ulsan. In Ulsan, there is a regional difference in the NTM species isolated.  相似文献   

5.
Background and objective:   Persistent smear-positivity in patients with pulmonary tuberculosis has been shown to predict an unfavourable outcome. This study was conducted to identify the factors influencing time to sputum smear conversion.
Methods:   From July 2003 to June 2007, all patients with smear-positive and culture-confirmed pulmonary tuberculosis, who had attended a medical centre and a local teaching hospital, were identified. Factors that might have influenced time to smear conversion were investigated using time-to-event analysis.
Results:   Altogether 305 patients (mean age: 58.6 years) were studied. Diabetes mellitus was the most common underlying comorbidity. Eight patients (2.6%) had AIDS. After 2 months of treatment, 34 (11.1%) patients remained smear- and culture-positive. Cox proportional hazard regression analysis indicated that the presence of a cavity on CXR, smear grading and the first 2-month treatment regimen were independent factors influencing the time to sputum smear conversion. Among patients who had received isoniazid in the first 2 months of treatment, the time to sputum smear conversion in the 24 patients whose isolate showed isoniazid resistance was not different from that in the 236 patients whose isolate was isoniazid-susceptible (hazard ratio 1.061; 95% CI: 0.697–1.616).
Conclusions:   This analysis revealed that 11.1% of tuberculosis patients remained smear-positive after 2 months of treatment. Patients with cavitation, higher smear grading and those who had not used isoniazid, rifampicin, ethambutol and pyrazinamide continuously in the initial treatment phase had a longer time to sputum smear conversion.  相似文献   

6.
Rapid diagnosis of pulmonary tuberculosis by mycobacteriophage assay.   总被引:1,自引:0,他引:1  
We evaluated FASTPlaqueTB, a recently introduced bacteriophage assay for rapid detection of Mycobacterium tuberculosis complex in sputum specimens, using 169 non-duplicate sputum specimens from patients suspected of pulmonary tuberculosis. The results of 160 specimens were analysed. FASTPlaqueTB assay detected tuberculosis in 77% (46/60) of culture-positive cases. Among the AFB smear-positive cases (n = 47) it had a sensitivity of 76% and specificity of 60% while among AFB smear-negative cases (n = 113) its sensitivity and specificity were 78% and 98%, respectively. The overall sensitivity and specificity of the technique were 77% and 96%, respectively, and the positive and negative predictive values were respectively 92% and 87%. The overall efficiency of the test was 89%. Test results were available in 48 h.  相似文献   

7.
The definitive diagnosis of pulmonary tuberculosis (PTB) relies on identifying or culturing Mycobacterium tuberculosis from respiratory specimens. National guidelines have recommended obtaining 3 sputum specimens from patients with suspected tuberculosis, but there has been little data on the number of specimens actually needed to support a diagnosis. We retrospectively reviewed all patients diagnosed with PTB at a public inner-city hospital and assessed the sensitivity of the acid-fast bacilli (AFB) smear and the number of smears needed to establish the diagnosis. Between January 1, 1997 and October 1, 2000, 425 patients were diagnosed with culture-proven PTB. Acid-fast bacilli (AFB) smears and cultures were performed on 951 respiratory specimens from 425 patients. The overall sensitivity of a positive AFB smear increased from 67% with 1 sputum collected to 71% and 72%, respectively, with the second and third specimens. The sensitivity of smears from 239 HIV-negative patients was 75%, 79%, and 80% with 1, 2, and 3 smears, respectively, collected compared with 57%, 61%, and 62%, respectively, for 142 HIV-positive patients. In summary, 2 respiratory specimens proved adequate in establishing a diagnosis of tuberculosis, and the third specimen added little additional diagnostic value.  相似文献   

8.
The early differentiation of Mycobacterium tuberculosis from non-tuberculous mycobacteria (NTM) and the identification of NTM species are crucial for the proper management of patients with smear-positive sputum. We evaluated the usefulness of a polymerase chain reaction restriction analysis (PRA) method based on the rpoB gene for identifying NTM species in a study of 121 smear-positive respiratory specimens with presumed NTM. The PRA method amplified mycobacterial DNA in 72 specimens (60%) and differentiated NTM species correctly in 68 (94%). The PRA method could be a useful and rapid method for identifying NTM species in smear-positive respiratory specimens when urgent clinical decisions are required.  相似文献   

9.
BACKGROUND: Sputum microscopy for acid-fast bacilli (AFB) is the commonest diagnostic method for pulmonary tuberculosis (PTB) in developing countries. The method is reported to be less sensitive in human immunodeficiency virus (HIV) positive compared to negative patients. We determined the bacillary density in sputum of smear-positive PTB patients and related it to the patients' HIV status, CD4 cell count, clinical and demographic characteristics. METHODS: Three sputum samples per patient were examined using microscopy before initiating therapy. The AFB density was graded according to World Health Organization recommendations. The smear with the highest density was used. High bacillary density was defined as >10 AFB/field. HIV status and CD4 cell count were determined according to the national guidelines. RESULTS: Of 844 patients, 433 (51.3%) were HIV-positive. High bacillary density was significantly less common among HIV-positive (39.0%) than -negative (75.7%) patients (prevalence ratio 0.52; 95%CI 0.45-0.59, P < 0.0001). Among HIV-positive patients, the proportion of those with high bacillary density increased progressively with CD4 cell counts (P = 0.003). CONCLUSION: HIV is associated with lower AFB concentration in sputum. The AFB density falls with falling CD4 cell count. Microscopy for AFB in sputum may be less sensitive in diagnosing PTB when HIV infection is present, especially in severely immunocompromised patients.  相似文献   

10.
ABSTRACT: BACKGROUND: This study was aimed to investigate the diagnostic value of fiberoptic bronchoscopy (FOB) with chest high-resolution computed tomography (HRCT) for the rapid diagnosis of active pulmonary tuberculosis (PTB) in patients suspected of PTB but found to have a negative sputum acid-fast bacilli (AFB) smear. METHODS: We evaluated the diagnostic accuracy of results from FOB and HRCT in 126 patients at Gangnam Severance Hospital (Seoul, Korea) who were suspected of having PTB. RESULTS: Of 126 patients who had negative sputum AFB smears but were suspected of having PTB, 54 patients were confirmed as having active PTB. Hemoptysis was negatively correlated with active PTB. Tree-in-bud appearance on HRCT was significantly associated with active PTB. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FOB alone was 75.9%, 97.2%, 95.3%, and 84.3%, respectively, for the rapid diagnosis of active PTB. The combination of FOB and HRCT improved the sensitivity to 96.3% and the NPV to 96.2%. CONCLUSIONS: FOB is a useful tool in the rapid diagnosis of active PTB with a high sensitivity, specificity, PPV and NPV in sputum smear-negative PTB-suspected patients. HRCT improves the sensitivity of FOB when used in combination with FOB in sputum smear-negative patients suspected of having PTB.  相似文献   

11.
SETTING: All non-private hospitals in Malawi. OBJECTIVES: To determine 1) how many patients with pulmonary tuberculosis (PTB) exceed the maximum number of visits needed for registration as defined by the National Tuberculosis Control Programme, and 2) the factors associated with this delay. DESIGN: Cross-sectional study interviewing hospitalised patients with new smear-positive and smear-negative PTB. RESULTS: Of 380 patients with PTB admitted to the 44 hospitals visited between April and June 2002, 329 (212 smear-positive and 117 smear-negative PTB) were interviewed: 64 (30%) smear-positive PTB patients needed more than five visits, and 44 (37%) smear-negative PTB patients needed more than six visits before being registered and started on treatment. Factors associated with exceeding the maximum number of visits were the first visit being to a health centre, submission of > 1 set of sputum specimens, and > 1 course of antibiotics. The main consequence of exceeding the maximum number of visits was increased duration of cough and increased time spent at health facilities. CONCLUSION: One third of patients exceed the maximum number of visits for registration of PTB. The main consequence of this is an increased duration of cough and an increased time spent at health facilities. Ways to reduce this delay need to be found.  相似文献   

12.
SETTING: Ntcheu District, Malawi, using an oral antituberculosis treatment regimen. OBJECTIVE: To determine whether directly observed treatment (DOT) during the initial phase of treatment supervised either in hospital, at health centres or by guardians in the community, was associated with 1) satisfactory 2-month and 8-month treatment outcomes, and 2) with a reduction of in-patient hospital-bed days. DESIGN: Prospective data collection of all tuberculosis (TB) patients registered between 1 April 1996 and 30 June 1997, with 2-month and 8-month treatment outcomes, sputum smear conversion in smear-positive pulmonary TB patients (PTB) and in-patient hospital-bed days. RESULTS: Among the 600 new patients, 302 had smear-positive PTB, 150 smear-negative PTB and 148 extrapulmonary TB (EPTB). Eight-month treatment completion was 65% for smear-positive PTB patients, which was significantly higher than in patients with smear-negative PTB (45%) and EPTB (54%), due mainly to high 8-month mortality rates. The site of the intensive phase was determined in 596 patients: 178 (30%) received DOT from guardians, 115 (19%) from a health centre and 303 (51%) in hospital. At 2 months, mortality rates were significantly higher in hospitalised patients. Two-month treatment outcomes (including sputum smear conversion rates in smear-positive PTB patients) were similar between patients receiving DOT at health centres or from guardians. Decentralised DOT resulted in a 25% reduction in hospital-bed days in patients alive at 2 months compared with that predicted using the old regimens. CONCLUSION: Decentralising DOT to health centres and to guardians during the intensive phase is associated with satisfactory treatment outcomes.  相似文献   

13.
Abstract Objectives: Pulmonary nontuberculous mycobacteria (NTM) are increasing worldwide, but data from regions with an intermediate tuberculosis (TB) burden are insufficient, and the reason for the changing epidemiology of NTM lung disease is unclear. We investigated the trends of NTM lung disease at a tertiary hospital in Korea and evaluated the contribution of liquid culture systems. Methods: We conducted a retrospective observational study of mycobacterial cultures of respiratory specimens from 26,793 patients at Severance Hospital in South Korea from January 2006 to December 2010. Results: The recovery percent of Mycobacterium tuberculosis isolates was 5.9% in 2006 and 7.1% in 2010, and the recovery percent of NTM isolates was 2.0% in 2006 and 6.3% in 2010. The annual percent of NTM isolation has increased steadily every year (p for trend 相似文献   

14.
SETTING: East Timorese refugees evacuated to Darwin, Australia, September 1999. OBJECTIVE: Presentation of the process and results of tuberculosis (TB) screening in a previously unscreened refugee population. DESIGN: Screening for TB by clinical examination (all persons) and chest X-ray (CXR) (persons over 12 years of age and those of any age with respiratory symptoms) and sputum microscopy and mycobacterial culture (abnormal CXR). RESULTS: Seventy-six patients were diagnosed with TB (38 culture-positive for Mycobacterium tuberculosis, including 11 sputum smear-positive). Of 89 positive mycobacterial cultures, 51 were non-tuberculous mycobacteria (NTM). Of the M. tuberculosis isolates, 82.2% were fully sensitive, 17.2% were resistant to isoniazid and 8.6% were resistant to isoniazid and streptomycin. Fifty-three consecutively diagnosed patients with TB were HIV-negative. The TB burden in this population was very high (point prevalence of 542/100,000 for smear-positive and 2,060/100,000 for culture-positive cases). Rates of culture for NTM were also high. Information from this study assisted the implementation of a National TB Control Programme for East Timor in February 2000. CONCLUSION: The challenges for public health authorities in East Timor to provide a successful TB control programme are enormous. The apparently low prevalence of drug resistance and HIV co-infection in the population is encouraging.  相似文献   

15.
SETTING: Tiruvallur District in Tamilnadu, South India, where the World Health Organization-recommended DOTS strategy was implemented as a tuberculosis (TB) control measure in 1999. OBJECTIVE: To assess the epidemiological impact of the DOTS strategy on the prevalence of pulmonary tuberculosis (PTB). DESIGN: Surveys of PTB were undertaken on representative population samples aged > or =15 years (n = 83000-90000), before and at 2.5 and 5 years after the implementation of the DOTS strategy. The prevalence of PTB (smear-positive/culture-positive) was estimated. RESULTS: TB prevalence declined by about 50% in 5 years, from 609 to 311 per 100000 population for culture-positive TB and from 326 to 169/100000 for smear-positive TB. The annual rate of decline was 12.6% (95%CI 11.2-14.0) for culture-positive TB and 12.3% (95%CI 8.6-15.8) for smear-positive TB. The decline was similar at all ages and for both sexes. CONCLUSION: With an efficient case detection programme and the DOTS strategy, it is feasible to bring about a substantial reduction in the burden of TB in the community.  相似文献   

16.
SETTING: An automatic acid-fast bacilli (AFB) stainer was developed to improve laboratory workflow and protect laboratory workers. OBJECTIVE: To determine the usefulness of the 7720 Aerospray AFB slide stainer for liquefied and concentrated respiratory specimens. DESIGN: With 24 smear-positive specimens submitted for AFB stain and culture in a tertiary care hospital, the autostainer was evaluated to determine whether smears would be sloughed from slides during the staining process by loading distilled water instead of staining reagents. With 109 more specimens, the performance of the 7720 Aerospray was compared with manual florescence staining as a gold standard. The tested smears were prepared with Mycohold treatment. RESULTS: In most cases, the slides exposed to the autostainer containing distilled water showed lower grades of AFB than those slides not exposed to the autostainer (14/24 in Mycohold-treated slides). Almost half (54/109, 49.5%) of the Mycohold-treated autostained smears had a lower grade than the same smears stained manually. Among 62 Mycohold-treated autostained smear-negative specimens, respectively eight (12.9%) and 19 (30.6%) were high and low false-negatives. CONCLUSION: The 7720 Aerospray showed poor performance in AFB staining of concentrated sputum specimens.  相似文献   

17.
SETTING: A tuberculosis (TB) prevalence survey was performed in 2002 in two urban communities in Cape Town, South Africa. The population was 36,334 in 2001, and the TB notification rate was 341 per 100,000 population for new smear-positive TB in 2002. OBJECTIVE: To evaluate the relative contributions of symptom and chest radiographic (CXR) screening in the detection of subjects with smear- and/or culture-positive TB in prevalence surveys. DESIGN: Information on symptoms, CXR abnormalities, sputum smear and culture was gathered from a random cluster sample of 1170 adults (aged > or = 15 years). Smear and/or culture-positive TB was used as the gold standard. RESULTS: Of 1170 adults, 29 had bacteriologically positive TB (smear- and/or culture-positive). The presence of any abnormalities on CXR had the highest sensitivity for detecting subjects with bacteriologically positive TB (0.97, 95%CI 0.90-1.00). Specificity for any abnormalities on CXR was 0.67 (95%CI 0.64-0.70). The specificity of any of five TB-related symptoms was 0.68 (95%CI 0.65-0.71). Individual symptoms had low sensitivities, ranging from 0.10 for fever to 0.54 for cough of > or = 2 weeks. CONCLUSION: In this TB prevalence survey, CXR screening, but not symptom screening, was a sensitive alternative to sputum examination of all participants.  相似文献   

18.
目的探讨基因芯片技术诊断肺结核及鉴定分枝杆菌菌种的应用价值。方法搜集2017年1-12月在黑龙江省传染病防治院结核科就诊并连续3次痰涂片检测为阳性的1248例疑似肺结核患者为研究对象。每例患者均留取清晨痰液标本3~5ml,对痰液标本分别进行BACTEC MGIT 960(简称"MGIT 960")培养和基因芯片检测。以MGIT 960培养结果作为参照,分析基因芯片法的检测效能。结果1248例患者痰标本经MGIT960培养阳性1224例(98.08%),基因芯片法检测阳性1212例(97.11%)。以MGIT 960培养结果作为参照,基因芯片法检测的敏感度为98.94%(1211/1224),特异度为95.83%(23/24),符合率为98.88%(1234/1248),Kappa值为0.76。1212例基因芯片法检测阳性的患者中非结核分枝杆菌(NTM)感染60例(4.95%),结核分枝杆菌感染1152例(95.05%)。60例NTM感染者中比较常见的菌种是胞内分枝杆菌(43.33%,26/60)。结论基因芯片检测与MGIT 960培养结果的一致性较好,可以快速、准确地区分结核分枝杆菌复合群和NTM,并可进一步进行菌种鉴定。  相似文献   

19.
SETTING: All non-private hospitals in Malawi that registered TB cases in 2001, during which there was a bus service for transporting sputum specimens to the Central Reference Laboratory (CRL) for mycobacterial culture and drug sensitivity testing (CDST). OBJECTIVES: To determine the performance of the system of collecting and processing sputum specimens from patients with recurrent smear-positive pulmonary TB through to CDST. DESIGN: Structured interviews with TB Officers, and retrospective data collection using TB and laboratory registers. RESULTS: There were 964 patients with recurrent smear-positive PTB. TB Officers took responsibility for collecting and transporting sputum to the CRL, and 73% reported using the bus service. Sputum specimens from 384 (40%) patients arrived at the CRL. Of these, 40% were found to have negative concentrated smears at the CRL, and 36% of specimen sets arriving at CRL were successfully cultured for DST. Most specimens had been collected after the start of anti-tuberculosis treatment. Although delays in collection adversely affected culture, only 43% of specimen sets collected on or before the first day of treatment yielded Mycobacterium tuberculosis. CONCLUSION: Problems were identified at all stages of the system and strategies to remedy these are being put in place.  相似文献   

20.
SETTING: Government hospitals in five districts in Malawi. OBJECTIVE: To determine care seeking behaviour and diagnostic processes in patients newly diagnosed with smear-positive pulmonary tuberculosis (PTB). DESIGN: Structured questionnaires completed by interview between January to September 1998. RESULTS: During the study period 1,518 patients were registered with PTB, of whom 1,099 (72%) were interviewed. The median delay between onset of cough and diagnosis was 8 weeks. There was a variable pattern of care seeking behaviour, with 70% of patients initially visiting a place of orthodox medical care and 30% visiting traditional healers, grocery shops, etc. Of these, 867 (79%) patients had one or more subsequent contacts for help, with these visits targeted more to orthodox medical care. At all stages, antibiotics resulted in symptomatic improvement in up to 40% of cases. There was a median time of 7 weeks between cough and first submission of sputum specimens. Almost all patients received sputum smear results after a median length of 4 days; 474 (43%) of patients were only aware of their diagnosis at the time of receiving smear results, this observation being significantly associated with lack of schooling and not knowing another person with TB. CONCLUSION: More needs to be done to educate communities and non-orthodox care providers about the diagnosis and treatment of TB.  相似文献   

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