Yield of gastric lavage and bronchial wash in pulmonary tuberculosis.

OBJECTIVE: To determine the yield of acid-fast bacilli (AFB) in gastric lavage and bronchial washing in adult patients clinically and radiologically suspected of pulmonary tuberculosis but who cannot produce sputum. METHODS: Selected adult patients were admitted to the ward; gastric lavage was done for 3 consecutive days after an overnight fast followed by bronchial wash. Specimens were immediately sent to laboratory for AFB direct smear and culture. RESULTS: The yield of AFB in gastric lavage on direct smear was 16/20 (80%) and 12/20 (60%) in the first and second samples, respectively. When combined, 18/20 (90%) were direct smear positive, while the third sample did not increase the yield. The yield of AFB culture in gastric lavage was 6/20 (30%) in both the first and second samples, while the combined results of the first and second samples were 8/20 (40%). The third sample did not increase the yield. In bronchial wash, AFB direct smear was positive in 18/20 (90%), while culture was positive in 14/20 (70%). CONCLUSION: Gastric lavage and bronchial washing are useful methods for the diagnosis of pulmonary tuberculosis in patients who cannot produce sputum. Two gastric lavage specimens are adequate. On comparison, bronchial wash is superior to gastric lavage in culture, but their yield on direct smear is equal.     

The validity of acid-fast smears of gastric aspirates as an indicator of pulmonary tuberculosis.

SETTING: A tuberculosis referral hospital in Canada. OBJECTIVE: To determine the validity of acid-fast (AFB) smears of gastric aspirates (GA) in the diagnosis of pulmonary tuberculosis, and to assess the prevalence of nontuberculous mycobacteria (NTM) in GA isolates from such patients. DESIGN: A retrospective case review of our experience with AFB smears (Kinyoun) and cultures of GA and sputum over a 3-year period. RESULTS: From 1994 to 1996 inclusive, 1155 GA were performed in 889 patients. Mycobacteria were cultured from 109 (9%) GA. Thirteen of these were positive on smear (sensitivity 19%). All GA that were positive on smear were culture positive for Mycobacterium tuberculosis. There were no false positive smears (specificity 100%). The sensitivity and specificity of the sputum smear were 45% and 99%, respectively. Of the 96 culture positive, smear negative GA, 54 grew M. tuberculosis and 42 grew an NTM. Of 13 patients who had sputum and GA studied coincidentally, and in whom the sputum was both smear and culture positive, the GA culture was positive in 13 and the smear was positive in eight (66%). CONCLUSION: AFB smear of GA is a relatively insensitive but highly specific indicator of pulmonary tuberculosis warranting institution of antituberculosis treatment. Gastric AFB smear positivity appears to reflect a high bacillary burden within the respiratory tract.     

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.     

Diagnostic value of gastric aspirate smear and polymerase chain reaction in smear-negative pulmonary tuberculosis

OBJECTIVE: The aim of this study was to determine the validity of acid-fast bacilli (AFB) smear and polymerase chain reaction (PCR) from gastric aspirates for the diagnosis of smear-negative pulmonary tuberculosis. METHODOLOGY: A cross-sectional study was conducted in a university hospital. One hundred and nine patients with suspected pulmonary tuberculosis in whom either sputum smears were negative or who were not producing sputum were recruited to the study. All patients underwent gastric aspiration after an overnight fast followed by standard fibreoptic bronchoscopy. Specimens were subjected to AFB smear, culture, and pathological examination. PCR was performed on culture filtrate after 1 week of incubation. RESULTS: Eight patients did not complete the follow-up schedule. Of the 101 patients with final outcomes, a diagnosis of pulmonary tuberculosis from microbiological evidence was established in 54 patients. The gastric aspirate smear, PCR, or either one of them was positive in 34, 30, and 39 tuberculosis patients, respectively. There were 13 false positive smears from 47 non-tuberculosis patients, with five resulting from non-tuberculous mycobacteria (NTM). The PCR was falsely positive in eight patients, five of whom had previous histories of tuberculosis. The overall sensitivity, specificity, positive predictive value, and negative predictive value of gastric aspirate examination by combined smear and PCR were 72, 58, 66, and 64%, respectively. CONCLUSIONS: Gastric aspiration is a useful tool for the diagnosis of smear-negative pulmonary tuberculosis warranting institution of antituberculosis treatment. Interpretation of the results should be cautious in those who have had tuberculosis in the past or who have been at risk for acquisition of NTM.     

Bronchoscopic aspiration and bronchoalveolar lavage in the diagnosis of sputum smear-negative pulmonary tuberculosis

The ability to make a definitive diagnosis in sputum smear-negative pulmonary tuberculosis by bronchoscopic aspiration, bronchoalveolar lavage (BAL), and examination of postbronchoscopy sputum were compared. Thirty-four patients with lesions on chest x-rays suspected of being pulmonary tuberculosis were entered into the study. The diagnosis of pulmonary tuberculosis was subsequently confirmed in 28 patients and the method of arriving at the final diagnosis was analyzed. A positive acid-fast bacilli (AFB) smear result was obtained in 4/28 (14%) of cases by a combination of bronchoscopic techniques and postbronchoscopy sputum examination. Prebronchoscopy sputum culture was positive in 12/28 (43%). Combined with bronchoscopy specimens, a positive AFB culture result was obtained in 26/28 (93%). Sputum examination, bronchoscopic aspiration, and BAL are complementary techniques and together they give a high yield of definitive diagnosis of pulmonary tuberculosis.     

Bronchoscopic aspiration and bronchoalveolar lavage in the diagnosis of sputum smear-negative pulmonary tuberculosis

The ability to make a definitive diagnosis in sputum smear-negative pulmonary tuberculosis by bronchoscopic aspiration, bronchoalveolar lavage (BAL), and examination of postbronchoscopy sputum were compared. Thirty-four patients with lesions on chest x-rays suspected of being pulmonary tuberculosis were entered into the study. The diagnosis of pulmonary tuberculosis was subsequently confirmed in 28 patients and the method of arriving at the final diagnosis was analyzed. A positive acid-fast bacilli (AFB) smear result was obtained in 4/28 (14%) of cases by a combination of bronchoscopic techniques and postbronchoscopy sputum examination. Prebronchoscopy sputum culture was positive in 12/28 (43%). Combined with bronchoscopy specimens, a positive AFB culture result was obtained in 26/28 (93%). Sputum examination, bronchoscopic aspiration, and BAL are complementary techniques and together they give a high yield of definitive diagnosis of pulmonary tuberculosis.     

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.     

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.     

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.     

Post-bronchoscopy sputum: improving the diagnostic yield in smear negative pulmonary TB

Introduction

Patients with suspected active Pulmonary Tuberculosis (PTB) who are Acid-Fast Bacilli (AFB) smear negative or non-productive of sputum may undergo bronchoalveolar lavage. However, post-bronchoscopy sputum (PBS) sampling is not routine. The aim of this study was to establish the potential diagnostic value of PBS sampling.

Methods

A retrospective study of patients attending a London University hospital with microbiologically confirmed PTB between January 2004 and December 2010. Patients who were AFB smear negative or non-productive of sputum were eligible if sputum sampling was performed within 7 days of bronchoscopy.

Results

Over the study period, 236 patients had microbiologically confirmed smear negative PTB of which 57 patients were eligible for the study. 15 patients (26.3%) were infected with HIV. 19 patients (33.3%) converted to AFB sputum smear positivity post-bronchoscopy and 5 patients (8.8%) were exclusively AFB sputum smear positive on PBS microscopy. Mycobacterium tuberculosis was cultured from the PBS of 43 patients (75.4%) and of these, 4 (7.0%) were exclusively PBS culture positive.

Conclusion

PBS analysis can provide a simple method of rapidly diagnosing pulmonary tuberculosis. In this cohort, M. tuberculosis culture yield was increased by 7% through PBS sampling. This study has important infection control implications with nearly one third of patients becoming more infectious after bronchoscopy.     

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.     

The significance of the persistent presence of acid-fast bacilli in sputum smears in pulmonary tuberculosis.

STUDY OBJECTIVES: Identification of acid-fast bacilli (AFB) in the sputum smear at the completion of tuberculosis therapy is in some settings considered evidence of treatment failure. However, some patients with pulmonary tuberculosis (TB) will have positive smear results with negative sputum culture results at the end of therapy. The objectives of this study were to estimate the prevalence of persisting positive sputum smear results in patients with TB and to identify characteristics that distinguish patients with persistently positive sputum smear results who also had negative sputum culture results from patients identified as treatment failures. DESIGN: A population-based, historical cohort study with nested case control study. SETTING: British Columbia Division of Tuberculosis Control central case registry. PATIENTS: All 428 patients with culture-proven pulmonary TB in British Columbia over 7 years with sputum that was positive for AFB. METHODS: Review of laboratory data of all 428 patients, as well as clinical data of a subset of 30 patients with persistently positive smear results beyond 20 weeks. RESULTS: Sputum smears were positive for AFB in 205 patients (48%) at 4 weeks, in 30 patients (7%) at 20 weeks, and in 12 patients (3%) at 36 weeks. Of the patients with smear results that were persistently positive at 20 weeks, 23 (77%) had negative sputum culture results and 7 (23%) had positive sputum culture results (ie, they were treatment failures). Patients identified as treatment failures had more localized disease as shown on chest radiographs, had less radiographic improvement at follow-up, had a higher prevalence of drug resistance, and were less compliant with medications than patients with persistently positive smear results and negative culture results. No subject with a negative culture result relapsed over the 6- to 48-month observation period. CONCLUSION: Sputum that is persistently positive for AFB in patients in developed countries is more likely to be associated with negative culture results than with treatment failure.     

微量支气管肺泡灌洗在菌阴肺结核诊断中的应用

目的　探讨微量支气管肺泡灌洗对菌阴肺结核的诊断价值。方法　对 18例临床高度怀疑肺结核的痰菌阴性患者行灌洗液为 4 0 ml的微量支气管肺泡灌洗 ,并对回收液涂片做抗酸杆菌检查、普通细菌培养、细胞学检查及术后痰涂片检查抗酸杆菌。并于术后 1周至 1月复查胸片。结果　微量支气管肺泡灌洗液 (BAL F)检查抗酸杆菌阳性率为 5 0 % ,联合术后痰涂片检查抗酸杆菌阳性率为 71.4 % ,与术前相比 ,差异有显著性 (P<0 .0 1)。术后无 1例出现并发症。结论　微量支气管肺泡灌洗对菌阴肺结核的诊断是一种安全实用的检查方法。     

Effectiveness of the BDProbeTec ET system for detection of Mycobacterium tuberculosis complex in sputum and bronchoalveolar lavage specimens

ObjectiveThe diagnostic efficacy of the BDProbeTEC ET Mycobacterium tuberculosis (MTB) complex direct detection assay (DTB) performed on bronchoalveolar lavage (BAL) specimens and sputum smears was compared with acid-fast bacilli (AFB) smear microscopy.MethodAFB smear microscopy, DTB and culture results of 286 patients with pulmonary tuberculosis were retrospectively reviewed. A total of 120 patients provided expectorated sputum samples, and 166 patients provided BAL specimens. Culture results and clinical diagnosis were used as gold standards.ResultsThe sensitivity and specificity of the DTB assay in detecting MTB in sputum specimens was significantly higher compared to AFB smear microscopy (83.7% and 82.4%, vs. 75.6%, and 41.2%, respectively). The sensitivity and specificity of the DTB assay in detecting MTB in sputum samples was 77.2% and 100% compared to clinical diagnosis, while AFB smear had a sensitivity and specificity of 70.3% and 26.3%, respectively. Compared to culture, DTB had a sensitivity and specificity of 82.8% and 93.2%, respectively, in detecting MTB from BAL specimens; AFB smear had a sensitivity and specificity of 41.9% and 87.7%, respectively. Compared to clinical diagnosis, DTB had a sensitivity and specificity of 67.2% and 100%, respectively, in detecting MTB from BAL specimens; AFB smear had a sensitivity and specificity of 34.8% and 79.5%, respectively.ConclusionsThe superior performance of the DTB assay relative to AFB smear microscopy makes it a valuable tool to enable early diagnosis of MTB, thereby improving patient care and reducing transmission.     

Combined bronchoalveolar lavage and polymerase chain reaction in the diagnosis of pulmonary tuberculosis in smear-negative patients.

SETTING: The polymerase chain reaction (PCR) may be sensitive and specific for the diagnosis of tuberculosis, but most reports are of studies conducted in well-controlled laboratories. A study to evaluate the clinical value of bronchoalveolar lavage (BAL) combined with PCR was necessary. OBJECTIVE: One hundred and thirty one patients were recruited into the study from March 1994 to February 1997. DESIGN: Patients with a positive acid-fast stain on sputum smear were recruited into group A as positive controls, patients with lung cancer and a negative acid-fast stain on sputum smear were put into group B as negative controls, and patients who had clinical symptoms of pulmonary TB without sputum or with negative smear results were the investigating group. PCR was performed on the sputum samples from group A and B patients and on the BAL fluid from those in group C. RESULTS: The sensitivity of PCR was 96% in group A, and the specificity was 100% in group B. The sensitivity of PCR in the BAL fluid from the group C patients was 36% and the specificity was 96%; the positive predictive value was 94% and the negative predictive value was 45%. CONCLUSION: BAL plus PCR is useful in the rapid diagnosis of pulmonary TB in non-productive or smear-negative patients.     

Number of negative acid-fast smears needed to adequately assess infectivity of patients with pulmonary tuberculosis

STUDY OBJECTIVES: To investigate the relationship between the number of negative acid-fast bacilli (AFB) smear results and infectivity of pulmonary tuberculosis (TB). DESIGN: Retrospective analysis. METHODS AND SUBJECTS: We examined 122 index cases in Harris County, TX, reported in 1998 and 1999. All cases had only negative AFB smear results during the infectious period and were categorized in two groups: group A consisted of cases with only one or two sputum specimens collected and processed, and group B consisted of cases with at least three sputum specimens or at least one bronchoscopic specimen. Tuberculin skin test (TST) results of contacts were ascertained from the results of contact investigations performed by the City of Houston Department of Health and Human Services, Tuberculosis Control Division. Univariate and multivariate analyses were done to explore index case and contact attributes associated with tuberculosis (TB) transmission using positive TST results of contacts as a measure of recent transmission. RESULTS: We found male gender and younger age of index cases along with Hispanic ethnicity of contacts to be independently associated with positive TST results, while younger contacts were less likely to be TST positive. Smear category of the index case (group A vs group B) was not independently associated with transmission. We also found that the first two sputum specimens in cases where three or more were performed yielded 90% of all positive culture results for Mycobacterium tuberculosis (MTB). CONCLUSIONS: We conclude that two sputum specimens negative for AFB stain are adequate for both assessing infectivity and for isolating MTB from patients with pulmonary TB.     

Role of Gene Xpert in smear negative pulmonary tuberculosis

BackgroundTuberculosis is a major health problem contributing to significant morbidity and mortality. Early diagnosis and treatment is the key for TB control. Sputum microscopy is a rapid and inexpensive test but due to low and variable sensitivity, many cases can be missed. Culture is considered to be the gold standard but is time consuming. Gene Xpert is a novel and rapid cartridge based nucleic acid amplification test (CBNAAT) that can be used for prompt diagnosis.AimTo compare the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of Gene Xpert with culture in diagnosing tuberculosis in sputum smear negative patients.MethodsThe study is a prospective observational study conducted from December 2017 to January 2019 on 189 patients, who were sputum smear negative but had signs and symptoms suggestive of tuberculosis. Their respiratory samples were taken (either sputum or bronchoalveolar lavage) and sent for Gene Xpert. The results were compared with culture, which was taken as the gold standard, and diagnostic accuracy was assessed.ResultA total of 189 patients were included in the study. In 25 patients sputum was taken and in 164 patients BAL was taken (which included 22 patients in whom sputum Gene Xpert was negative but there was high clinical suspicion of tuberculosis). The sensitivity, specificity, PPV and NPV of Gene Xpert in diagnosing smear negative pulmonary tuberculosis was found to be 96.3%, 81.3%, 87.5% and 94.2% respectively.ConclusionGene Xpert can be used as a rapid diagnostic tool in patients who are sputum smear negative but have clinical features highly suggestive of tuberculosis. It additionally helps in detecting rifampicin resistance. But every Gene Xpert positive case does not necessarily mean an active disease, therefore, past history of tuberculosis along with radiological signs of disease activity are to be considered. In case of negative Gene Xpert but high clinico-radiological suspicion of TB, patients should be followed up on regular intervals, while awaiting their culture.     

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。     

High-resolution CT findings in patients with pulmonary tuberculosis: correlation with the degree of smear positivity

BACKGROUND: There are data about the relationship between morphologic findings on high-resolution computed tomography (HRCT) and the number of acid-fast bacilli (AFB) on sputum smears in patients with pulmonary tuberculosis (PTB). It was also shown that existence of cavities and airspace consolidation might be related to smear positivity in PTB patients. However, there is no study suggesting a relationship between AFB on sputum smears and radiologic extent of disease based on HRCT findings. AIM: In this study, we investigated a relationship between the degree of smear positivity and radiologic extent of disease based on HRCT findings and, the degree of smear positivity and different pulmonary parenchymal changes on HRCTs of the PTB patients. METHODS: Sixty-one male patients with PTB (mean age: 22+/-3.2) were included into the study. HRCT images were assessed for patterns, distribution, and profusion of pulmonary abnormalities. Dividing the lungs into 3 zones, profusion of abnormalities was assessed. A profusion score was given. Patients were divided as smear positive and smear negative and compared for the scores of HRCT findings. Smear-positive patients were divided into 4 groups as per grading of the sputum AFB smear: group I (sputum 1+), group II (sputum 2+), group III (sputum 3+), and group IV (sputum 4+). Correlations were investigated between the degree of smear positivity and the scores of HRCT findings. RESULTS: A significant correlation between radiologic extent of the disease based on HRCT and the degree of smear positivity was found (r=0.63, P=0.0001). There were also significant correlations between the degree of smear positivity and the scores of different HRCT findings. Nodule, cavity, and bronchial lesions are the most important contributors of the predictive properties of the total score. There was significant differences for the scores of HRCT findings between smear-positive and smear-negative patients. CONCLUSIONS: Our study suggests that radiologic extent of disease based on HRCT findings in patients with PTB correlated with the degree of smear positivity. Different HRCT findings such as nodule, cavitation, ground-glass opacity, consolidation, and bronchial lesion are significantly associated with smear-positive PTB. Particularly, nodules, cavities, and bronchial lesions might be predictors of smear positivity in patients with PTB. This study also suggests that the thickness of cavity wall and the distance of cavity from central airways might be related to the degree of smear positivity.