The role of bronchoscopy in the diagnosis of pulmonary tuberculosis in patients at risk for HIV infection.

The present study was undertaken to clarify the role of bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB) in the diagnosis of pulmonary tuberculosis in patients at risk for human immunodeficiency virus (HIV) infection. We retrospectively identified 31 patients at risk for HIV who proved to have Mycobacterium tuberculosis on culture of at least one pulmonary specimen. All had pulmonary symptoms but initial sputum smears negative for acid-fast bacilli (AFB). All underwent fiberoptic bronchoscopy (FOB), including BAL and TBB; postbronchoscopy sputum was also collected in 19 patients. A specimen was considered to yield an immediate diagnosis when positive for AFB either on smear or histologic study; granulomas alone were considered positive when no other causes were identified. Overall, an immediate diagnosis was made by bronchoscopic specimens in 15 (48 percent) of 31 cases. TBB was the sole positive specimen in seven patients (23 percent). For comparison, similar specimens from 40 patients in whom M avium complex (MAC) grew on culture were also evaluated. An immediate identification of AFB was made in only four patients (10 percent). We conclude that the finding of AFB on staining of any pulmonary specimen is highly suggestive of tuberculosis, rather than MAC, and warrants institution of antituberculosis therapy. Of all bronchoscopic specimens, TBB provides the highest yield for an immediate diagnosis of tuberculosis.     

Bronchoscopy and transbronchial biopsy in evaluation of patients with suspected active tuberculosis

To assess the value of fiberoptic bronchoscopy and transbronchial biopsy for evaluating patients suspected of having tuberculosis, we reviewed the records of 56 patients (1974–1980). All patients (1) were clinically suspected of having active tuberculosis; (2) had an abnormality on chest roentgenogram consistent with tuberculosis; (3) had an absence of acid-fast bacilli on three sputum smears or an inability to produce sputum; (4) had undergone fiberoptic bronchoscopy and transbronchial biopsy. The evaluations included fiberoptic bronchoscopy with collection of bronchial washings and brushings, and transbronchial biopsy and postbronchoscopy sputum specimens. Thirteen patients subsequently underwent percutaneous needle aspiration and one underwent thoracotomy.

Evaluations were diagnostic in 29 of the 56 patients (52 percent). Diagnoses were mycobacterial infection in 22 (39 percent) and other disease processes in seven (13 percent). Fiberoptic bronchoscopy and transbronchial biopsy provided a diagnosis when sputum cultures obtained before bronchoscopy were negative for Mycobacteria in 11 (20 percent) patients. Immediate diagnoses were made from microscopic specimens obtained from 11 of 23 (48 percent) fiberoptic bronchoscopy and transbronchial biopsy procedures on patients with previously undiagnosed mycobacterial infection. Transbronchial biopsy had the best yield for a microscopic diagnosis. On culture, bronchoscopy specimens had a lower yield (10 of 23 or 44 percent) than sputum specimens obtained before bronchoscopy (14 of 21 or 67 percent) probably due to the inhibition of mycobacterial growth by tetracaine. Of the patients in whom evaluation proved nondiagnostic, 17 of 27 were lost to follow-up; therefore, a definitive statement regarding the number of false negative evaluations is not possible.

Fiberoptic bronchoscopy and transbronchial biopsy (FFB/TBB) is a useful procedure in evaluating patients with negative smears who are clinically suspected of having tuberculosis. It can improve the ability to document active tuberculosis, provide a sensitive means of making an immediate diagnosis, and uncover other disease processes presenting like tuberculosis.     

纤维支气管镜检查对无痰或痰菌阴性不典型肺结核的诊断价值

目的 探讨纤维支气管镜（简称“纤支镜”）检查对无痰或痰菌阴性不典型肺结核的诊断价值。 方法 选无痰或痰菌阴性的不典型肺结核患者201例,用纤支镜在病变部位进行活检、刷检、支气管肺泡灌洗液（BALF）进行BBLMGIT(Mycobacteria Growth Indicate Tube)分枝杆菌快速培养查结核杆菌。术后进行痰涂片查抗酸杆菌、痰结核分枝杆菌快速培养。 结果201例刷检、BALF快速培养结核分枝杆菌阳性率分别是67.2%、83.6%,61例活检阳性率63.9%,201例术后痰涂片、术后痰快速培养结核分枝杆菌阳性率分别是28.9%、57.2%。 结论 纤支镜检查是确诊无痰或痰菌阴性不典型肺结核的有效方法 ,其中BALF行结核分枝杆菌快速培养具有较高的诊断价值、快速、阳性率较高。根据镜下所见采用不同的取材方法 可望提高诊断率。     

Diagnostic value of bronchoscopy in diagnosis of pulmonary tuberculosis: bronchial aspirate, bronchial washing and transbronchial lung biopsy

The diagnosis of pulmonary tuberculosis is confirmed by the detection of Mycobacterium tuberculosis in sputum. Bronchoscopy has been used for diagnosis of various pulmonary diseases. The value of bronchoscopy such as bronchial aspirate, bronchial washing and transbronchial lung biopsy in diagnosis of pulmonary tuberculosis was evaluated, and the results were as follows: 1) One hundred ninety cases were investigated bronchoscopically due to suspicion of pulmonary tuberculosis with sputum negative smear and 92 cases were confirmed to be pulmonary tuberculosis. 2) Out of 91 cases examined by bronchial aspirate and 46 cases by bronchial washing, smear positivity was 20.9% and 23.9% and culture positivity was 58.2% and 84.8%, respectively. Transbronchial lung biopsy showed positive findings of tuberculosis in 75.8% out of 33 specimens. 3) Out of 88 sputa taken before bronchoscopy and 50 sputa after bronchoscopy, smear positivity was 0% and 12%, and culture positivity was 54.5% and 40% respectively. Gastric lavage culture positivity was 29.4% in 17 cases examined. 4) Diagnosis of tuberculosis was made rapidly in 28 cases (30.4%) by smear positive results of bronchial aspirate, bronchial washing and sputa after bronchoscopy, and relatively rapidly in 20 cases (21.7%) by transbronchial lung biopsy.     

Diagnostic usefulness of transbronchial aspiration and bronchial lavage for pulmonary tuberculosis

Fiberoptic bronchoscopy is a well established methods as a useful tool in the diagnosis of pulmonary tuberculosis with smear negative cases. In order to get the early and definite diagnosis of pulmonary tuberculosis, we performed transbronchial aspiration and bronchial lavage by a fiberoptic bronchoscope in 97 patients. All patients (1) were clinically suspected of having active tuberculosis; (2) showed abnormal chest roentgenogram suggesting tuberculosis; (3) showed negative sputum smears of acid-fast bacilli, or had no sputum. The results of the study were summarized as follows: 1) Final diagnosis of study subjects were 90 patients of active pulmonary tuberculosis, and 7 patients of pulmonary atypical mycobacteriosis. 2) Sputum culture of acid-fast bacilli was positive in 22 out of 90 patients with active pulmonary tuberculosis. 3) Smear and culture examination of acid-fast bacilli of transbronchial aspirates were positive in 9 and 28, respectively out of 90 patients. 4) Smear and culture examination of acid-fast bacilli of bronchial lavage were positive in 12 and 39, respectively out of 90 patients. 5) A rapid and definite diagnosis was made in 16 out of 90 patients by transbronchial aspirates or bronchial lavage. 6) Atypical mycobacteria were detected in 7 out of 97 patients by transbronchial aspirates or bronchial lavage. 7) There were no serious complications such as pneumonia and exacerbation of pulmonary tuberculosis. These results suggested that transbronchial aspiration and bronchial lavage were useful procedures for rapid and definite diagnosis of pulmonary tuberculosis.     

Comparison of sputum induction with fiberoptic bronchoscopy in the diagnosis of tuberculosis: experience at an acquired immune deficiency syndrome reference center in Rio de Janeiro, Brazil

Many patients with suspected pulmonary tuberculosis (PTB) do not produce sputum spontaneously or are smear-negative for acid-fast bacilli (AFB). We prospectively compared the yield of sputum induction (SI) and fiberoptic bronchoscopy with bronchoalveolar lavage (BAL) for the diagnosis of PTB in a region with a high prevalence of tuberculosis and human immunodeficiency virus (HIV) infection. Fifty seven percent (143 of 251) of patients had diagnoses of PTB, of whom 17% (25 of 143) were HIV seropositive. There were no significant differences in the yields of AFB smears or cultures whether obtained via SI or BAL. Among 207 HIV-seronegative patients, the AFB smear and mycobacterial culture results from specimens obtained by SI and BAL were in agreement in 97% (202 of 207) (kappa test = 0.92) and 90% (186 of 207) (kappa test = 0.78), respectively. Among HIV-seropositive patients the agreements between AFB smear and culture results for SI and BAL specimens were 98% (43 of 44) (kappa test = 0.93) and 86% (38 of 44) (kappa test = 0.69), respectively. We conclude that SI is a safe procedure with a high diagnostic yield and high agreement with the results of fiberoptic bronchoscopy for the diagnosis of PTB in both HIV-seronegative and HIV-seropositive patients.     

Value of smear and PCR in bronchoalveolar lavage fluid in culture positive pulmonary tuberculosis.

At present, further investigations are needed in patients with suspected pulmonary tuberculosis (TB) and either negative sputum smear or without sputum. The aim of the present study was to analyse the yield of bronchoalveolar lavage fluid (BALF) smear and PCR in patients with confirmed pulmonary TB. Patients with a positive culture for Mycobacterium tuberculosis complex in sputum or BALF were analysed over 5 yrs. In total, 90 out of 230 (39%) patients with culture-positive pulmonary TB had a positive sputum smear, and 120 patients underwent bronchoscopy. BALF smear was positive in 56 (47%), BALF PCR in 93 (78%) patients, and BALF smear and/or PCR was positive in 83%. In total, 71 patients who underwent bronchoscopy and had complete clinical records were further analysed. BALF (smear or Mycobacterium tuberculosis complex-PCR) allowed a rapid diagnosis in 10 (59%) out of 17 patients who had a negative sputum smear, and 49 (91%) out of 54 patients without sputum production. Of these 71 patients, 12 (17%) were only culture positive. Rapid diagnosis of pulmonary TB by smear and/or PCR was made in 190 out of 210 patients (90%) in sputum or BALF. In conclusion, combined use of bronchoalveolar lavage fluid smear and Mycobacterium tuberculosis complex-PCR has a good diagnostic yield in patients with sputum smear-negative tuberculosis or without sputum production.     

The value of fiberoptic bronchoscopy in diagnosis of smear negative pulmonary tuberculosis

Although mycobacterial culture positivity is the gold standard for the diagnosis, the initial approach to the diagnosis of pulmonary tuberculosis (PTbc) is the detection of acid-fast bacilli (AFB) in respiratory specimens as recommended by the World Health Organization. But the physicians have to make a decision for the patients whose sputum smears are negative or who can not produce sputum. Waiting for culture results with radiological follow up or empirical antituberculous therapy are the standard options. In our study we aimed to assess the diagnostic yield of fiberoptic bronchoscopy in patients, suspected to have tuberculosis, whose sputum smears were negative or who could not produce sputum. Fifty six patients who suspected to have PTbc with sputum smear negative were enrolled in the study (fiberoptic bronchoscopy and selective bronchial washings were done to all patients. Bronchial washings were obtained from the affected parts). Mucosal biopsies were done in patients in where endobronchial abnormalities were noted. Transbronchial biopsies were done in selected patients from the radiological localizations. Ziehl-Nielsen staining and culture in L?wenstein-Jensen medium were the microbiological studies. Typical granulomas were expected to detect on histopathologic examination. Bronchoscopic lavage smears were positive for Mycobacterium tuberculosis in 13 (23%) patients. Twenty eight (50%) patients had positive culture. Histopathological results confirmed tuberculosis in eight of 20 patients who had undergone mucosal biopsies, four of seven of transbronchial biopsies, two of three of needle aspiration biopsies. By bronchoscopic procedures early diagnosis was performed in 27 (48.21%) patients. We concluded that fiberoptic bronchoscopy has an important role in the diagnosis of patients suspected to have tuberculosis, whose sputum smears were negative or who could not produce sputum. It is useful and necessary in selected cases.     

纤支镜灌洗液的结核分支杆菌快速培养对不典型肺结核的诊断价值

目的　评价纤维支气管镜(以下简称纤支镜)支气管肺泡灌洗液(BALF)的结核分支杆菌快速培养对不典型肺结核的诊断价值。方法 选无痰或痰菌阴性的不典型肺结核患者49例行纤支镜检查,进行活检、刷检、BALF经BBLMGIT分支杆菌快速培养查结核杆菌。结果 49例经纤支镜刷检、BALF快速培养结核分支杆菌检出率分别是67.4%、83.7%,其中15例经纤支镜肺活检,10例病理证实为结核肉芽肿,检出率为66.7%。结论 纤支镜对无痰或痰菌阴性下BALF行结核分支杆菌快培对不典型肺结核具有较高的诊断价值,快速,阳性率较高。根据镜下所见采用不同的取材方法可望提高诊断率。     

BACTEC MGIT 960和BACT/ALERT 3D系统快速培养和鉴定痰中抗酸杆菌

目的对抗酸染色阳性痰行分枝杆菌培养和鉴定。方法采用萋一尼氏抗酸染色法对临床诊断肺结核患者的晨痰涂片直接镜检,抗酸染色阳性痰经BACTEC960和BACT/ALERT3D系统进行分枝杆菌培养,分别经对硝基苯甲酸（PNB）和噻吩-2-羧基肼（TCH）培养基生长试验行分枝杆菌菌群和结核分枝杆菌复合群菌种鉴定。结果抗酸染色阳性痰标本的分枝杆菌培养阳性率100％,大多数为结核分枝杆菌（9／10）,少数为非结核分枝杆菌（1／10）,最快6天即可报告分枝杆菌阳性培养。结论BACTEC 960和BACT／ALERT3D系统具有快速培养分枝杆菌作用,抗酸染色阳性痰有必要行分枝杆菌培养和鉴定,有利于肺结核与非结核分枝杆菌病的鉴别诊断、结核分枝杆菌菌种鉴定和抗结核药物敏感性试验。     

Use of mycobacterial smears in the diagnosis of pulmonary tuberculosis in AIDS/ARC patients

Pulmonary tuberculosis in AIDS/ARC patients is an increasing problem. To assess the utility of acid-fast smears of pulmonary secretions in this patient population, we evaluated 38 AIDS/ARC patients with culture-positive pulmonary infection. A control group consisted of 57 non-AIDS/ARC patients, who also did not belong to an AIDS risk group, diagnosed during the same period. The number of culture-positive sputum samples evaluated per patient was similar in both groups (3.82 +/- 3.11 AIDS/ARC vs 4.47 +/- 2.83 control group). Significantly fewer AIDS/ARC patients, 45 percent, however, had a positive acid-fast smear compared with the control group, 81 percent (p less than 0.001). The initial sputum smear submitted was positive in only 29 percent of the AIDS/ARC group compared with 61 percent of control subjects (p less than 0.01). Further, greater than or equal to 5 negative smears were found in 60 percent of the evaluable AIDS/ARC patients compared with just 13 percent of control subjects (p less than 0.01). More extensive findings on chest roentgenograms were not associated with a significantly higher yield of smear positivity in the AIDS/ARC group. We conclude that acid-fast smears on sputum specimens are a relatively insensitive test for pulmonary tuberculosis in AIDS/ARC patients.     

The role of fiberoptic bronchoscopy for diagnosis of pulmonary tuberculosis in patients at risk for AIDS.

In patients with acquired immunodeficiency syndrome (AIDS)-associated pulmonary Mycobacterium tuberculosis (MTB) (group 1), we analyzed whether the addition of transbronchial biopsy (TBB) and bronchial brushings augmented the diagnostic MTB yield over nonbiopsy sampling. Positive acid-fast bacilli (AFB) smears from combined sputum, bronchoalveolar lavage (BAL), and washings were 30 percent compared with 37 percent when brushings and TBB were added (p = NS). The addition of TBB increased culture yield from 96 percent to 100 percent (p = NS). Similar results were seen in patients with pulmonary MTB without human immunodeficiency virus (HIV) risk factors (group 2). Group 1 patients most commonly had a nonspecific inflammation on TBB histopathology and had a lower incidence of granuloma formation than group 2 (p less than 0.05). Our results suggest that more invasive sampling with bronchial brushings and TBB does not contribute to the microscopic, bacteriologic, or histopathologic diagnosis of pulmonary MTB, independent of AIDS risk factors.     

Delayed diagnosis of tuberculosis in patients with human immunodeficiency virus infection

PURPOSE: To determine the frequency with which the diagnosis of tuberculosis is delayed in patients with concomitant human immunodeficiency virus (HIV) infection, and to identify reasons for such delays. PATIENTS AND METHODS: We reviewed medical records of 52 consecutive HIV-infected patients with culture-proven tuberculosis seen at a 1,900-bed general hospital serving a predominantly indigent population in Los Angeles, where the prevalences of HIV infection and tuberculosis are high. The late-treatment (LT) group consisted of 25 patients in whom tuberculosis was untreated prior to death (n = 6) or treated more than 22 days after presentation (n = 19). The early-treatment (ET) group comprised 27 patients in whom antituberculous therapy was begun less than 16 days after presentation. RESULTS: Symptoms, physical and laboratory findings, chest roentgenographic abnormalities suggestive of tuberculosis (hilar adenopathy, pleural effusion, miliary pattern, cavitation, predominant upper lobe infiltrate), and frequencies of concomitant nontuberculous disease were similar in LT and ET groups. Delayed diagnosis of tuberculosis was attributable to errors in management in 21 (84%) of 25 LT group patients. The most common error was failure to obtain at least three sputum samples for acid-fast smear and mycobacterial culture in patients with clinical and chest roentgenographic findings compatible with tuberculosis (15 cases). Acid-fast sputum smears were positive in 25 (61%) of 41 cases of pulmonary tuberculosis. Acid-fast smears of stool were positive in eight (42%) of 19 cases. Blood cultures yielded Mycobacterium tuberculosis in 18 (38%) of 48 cases. CONCLUSIONS: Delayed therapy of tuberculosis in HIV-infected patients at our medical center was common and was not due to atypical manifestations of tuberculosis. In most cases, delays could have been avoided if adequate numbers of sputum samples for acid-fast smear and mycobacterial culture had been obtained, and if empiric antituberculous therapy had been given to symptomatic patients in whom chest roentgenographic findings were suggestive of mycobacterial disease.     

Induced sputum improves the diagnosis of pulmonary tuberculosis in hospitalized patients in Gaborone, Botswana

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.     

纤支镜在菌阴肺结核中的应用评估

目的 观察纤支镜在菌阴肺结核诊断中的价值.方法 分析190例入院时痰涂片和PCR分析均为阴性疑诊为肺结核患者的病例资料,从经纤支镜抗酸杆菌涂片的阳性率、PCR检测结核分枝杆菌阳性率、上皮性肉芽肿支气管活检、结核分枝杆菌的培养阳性率等四个方面进行分析.结果 190例病例中,经纤支镜取样的阳性率:42.6％(痰涂片),63.6％(PCR分析),31.2％(肉芽肿支气管活检),54.2％(痰培养),将各种检查手段联合起来,诊断率可以达到85.2％.结论 经纤支镜取样有较高阳性率,可以提供快速明确的结核诊断.     

117例HIV／AIDS病人合并肺结核的临床特点

目的分析艾滋病病毒（HIV）感染者／艾滋病（AIDS）病人合并肺结核的临床特点,提高诊疗水平。方法对1997年7月至2011年7月间,住院的HIV／AIDS合并肺结核的病人,回顾分析其末梢血CD＋T淋巴细胞（简称CD4细胞）计数与结核菌素纯蛋白衍生物试验（PPD试验）、痰涂片、结核抗体以及纤维支气管镜灌洗液涂片的关系。结果117例病人中,cD。细胞计数〈50个／mm3时,PPD试验无阳性反应,痰涂片阳性率为20．0％（3／15）,结核抗体阳性率为26．7％（4／15）;CD4细胞计数在50～200个／mm3时,PPD试验阳性率为25．0％（16／64）,痰涂片阳性率为40．6％（26／64）,结核抗体阳性率为35．9％（23／64）;CD4细胞计数在200～500个／mm3时,PPD试验阳性率为55．3％（21／38）,痰涂片阳性率为60．5％（23／38）,结核抗体阳性率为52．6％（20／38）,其中65例痰涂片阴性患者经纤维支气管镜灌洗液涂片有29例（44．6％）抗酸杆菌阳性;CD4细胞计数〉500个／mm3时,痰涂片阳性率为71．4％（5／7）,结核抗体阳性率为57．1％（4／7）。结论CD4细胞计数在500个／mm3以上时,痰涂片阳性率、结核抗体阳性率与HIV阴性肺结核检测相近,CD4细胞计数在200个／mm3以下时,临床表现较为复杂,数值越低合并肺结核症状越重,PPD试验反应、痰涂片、结核抗体以及纤维支气管镜灌洗液涂片阳性率越低。     

Utility of blood cultures and incidence of mycobacteremia in patients with suspected tuberculosis in a South African infectious disease referral hospital.

SETTING: A 500-bed government referral institution for patients with tuberculosis and other infectious diseases in Gauteng, South Africa. OBJECTIVES: To assess the usefulness of BACTEC blood cultures over and above that of other microbiological methods for the diagnosis of tuberculosis in patients who are suspected of suffering from tuberculosis. DESIGN: Mycobacterial blood cultures were obtained from patients presenting with symptoms suspicious of tuberculosis and where there was no clinical evidence of other infectious etiologies, and from patients who had failed tuberculosis treatment. RESULTS: Sixteen (22%) of 71 patients included in the study were positive for Mycobacterium tuberculosis on blood culture, while seven (10%) were positive for M. avium complex (MAC). Twelve (75%) of the patients with tuberculosis and positive blood cultures were however also positive for acid-fast bacilli on sputum smears and eight (50%) were initially diagnosed clinically and radiographically as localized pulmonary tuberculosis. Blood cultures positive for mycobacteria were only found among patients with human immunodeficiency virus infection (HIV). CONCLUSIONS: Bacteremia with M. tuberculosis complex was detected in HIV-infected patients with suspected tuberculosis, even in patients presenting with localized pulmonary infection on initial clinical assessment. Among patients with suspected tuberculosis, blood cultures were useful in diagnosing unsuspected MAC disease, but did not add to the diagnostic yield of conventional tests for tuberculosis used routinely, namely sputum microscopy and culture, or occasional biopsy specimens.     

Detection of Mycobacterium tuberculosis in bronchoalveolar lavage from patients with sputum smear-negative pulmonary tuberculosis using a polymerase chain reaction assay

Abstract The objective of this study was to evaluate the utility of a polymerase chain reaction (PCR) assay in detecting Mycobacterium tuberculosis in bronchoalveolar lavage (BAL) specimens of patients suspected of having active pulmonary tuberculosis (TB) but who were sputum smear-negative. Patients undergoing investigation for suspected pulmonary TB at the University Hospital, Kuala Lumpur, and who were sputum smear-negative underwent fibreoptic bronchoscopy and BAL. One portion of each lavage specimen was submitted for smear examination for acid-fast bacilli and mycobacterial culture and the other portion assayed by PCR for the presence of a 562-base pair DNA segment belonging to the insertion sequence IS986, unique to the M. tuberculosis complex. As controls, lavage specimens from patients with other lung lesions were also similarly tested. The PCR assay gave a positivity rate of 80.9% (55 of 68) compared with 8.8% of smear examination and 7.4% of culture for detecting M. tuberculosis in BAL specimens. The assay was positive in two of 45 BAL specimens from 35 control subjects. The PCR assay was more sensitive than smear and culture in detecting M. tuberculosis in BAL specimens of patients with sputum smear-negative pulmonary TB.     

Risk factors for transmission of Mycobacterium tuberculosis from HIV-infected tuberculosis patients, Botswana.

OBJECTIVE: To identify risk factors for transmission of Mycobacterium tuberculosis from patients with tuberculosis and human immunodeficiency virus (HIV) infection in Botswana. DESIGN: Transmission was studied in 210 children aged <10 years (contacts) of unknown HIV status exposed to 51 adults with tuberculosis (index cases), including 41/49 (83.7%) with HIV infection. METHODS: Data collected on index cases included demographics, clinical and social characteristics, sputum, HIV, and CD4 lymphocyte results. Tuberculin skin testing was performed on contacts, and their parent or guardian was interviewed. A positive test was defined as > or = 10 mm induration. Skin test results were compared with results obtained from a population survey of children of similar age from the same community. RESULTS: A positive skin test was found in 12.1% of exposed children compared with 6.2% in the community (P = 0.005). Of the infected children, 22 (78.6%) were contacts of a close female relative. The risk of transmission increased with the degree of sputum smear positivity for acid-fast bacilli among female index cases (10.8% if smear 0+, 9.3% if smear 1+,29.4% if smear 2+, 44% if smear 3+, P < 0.001). In multivariate analysis, severe immunodeficiency (CD4 lymphocyte count <200 cells/mm3) among HIV-infected index cases was protective against transmission (OR 0.08, 95%CI 0.01-0.5, P = 0.006). CONCLUSION: The intensity of exposure to tuberculosis patients and the degree of sputum smear positivity for acid-fast bacilli remain important risk factors for transmission of M. tuberculosis during the era of HIV. However, tuberculosis patients with advanced AIDS may be less infectious than patients in earlier stages of AIDS.     

A tuberculostearic acid assay in the diagnosis of sputum smear-negative pulmonary tuberculosis. A prospective study of bronchoscopic aspirate and lavage specimens

OBJECTIVE: To determine whether the detection of tuberculostearic acid (TBSA) in bronchial aspirate and bronchoalveolar lavage specimens is useful for the rapid diagnosis of active pulmonary tuberculosis in patients suspected of having the disease. SETTING: A pulmonary clinic in a teaching hospital. PATIENTS: Forty patients suspected of active pulmonary tuberculosis but who failed to produce sputum or whose sputum smears were negative for acid-fast bacilli on at least 3 occasions, 29 of whom were subsequently confirmed to have tuberculosis. A group of 13 patients who were having fiberoptic bronchoscopy for other reasons served as controls. INTERVENTION: All patients had fiberoptic bronchoscopy; bronchial aspirate, bronchoalveolar lavage, and sputum specimens were obtained when possible. MEASUREMENTS AND MAIN RESULTS: All specimens were examined microscopically for acid-fast bacilli, cultured for mycobacteria, and assayed for TBSA by gas chromatography and mass spectrometry with selected ion monitoring. Only 4 of the 29 patients with tuberculosis were diagnosed by direct microscopy compared with 26 by TBSA assay. In 2 patients who required surgical biopsy for conventional diagnosis, the TBSA test was positive. There were no false-positive TBSA results in the 13 controls, but 2 of 5 sputum specimens from the 11 test patients in whom tuberculosis was excluded were falsely positive, probably because of contamination with mouth flora. Because sputum can rarely be obtained from these patients and may give false-positive results, it is not a good specimen for TBSA assay. Sensitivities and specificities of the test for the other specimens were as follows: aspirate, 0.52 (CI, 0.32 to 0.71) and 1.00 (CI, 0.75 to 1.00); lavage, 0.68 (CI, 0.46 to 0.85) and 1.00 (CI, 0.84 to 1.00); aspirate and lavage combined, 0.79 (CI, 0.60 to 0.92) and 1.00 (CI, 0.86 to 1.00). CONCLUSIONS: The TBSA assay for bronchial aspirate and bronchoalveolar lavage fluid is useful for rapidly diagnosing "smear-negative" pulmonary tuberculosis. In these specimens it is highly specific and more sensitive than microscopy. This assay could be used to diagnose other mycobacterial infections, however, it cannot distinguish among species.