| BackgroundTuberculosis, causing by mycobacterium tuberculosis, is a chronic systemic infectious disease. Accompaning with increasing migrants, extensive employment of immunosuppressant, increasing HIV infectors and appearance of multifarious drug-resistant tuberculosis strains since 1980 s, the morbidity of tuberculosis(including extrapulmonary tuberculosis) has an obvious elevation in developing countries.At present, about 1,300,000 peoples per year are diagnosed tuberculosis in China, whose morbidity ranks the second in the world. In the prevention and treatment for tuberculosis,isolated culture of mycobacterium tuberculosis remains the gold standard. However,because the positive rate in culture is only 35% approximately and culture cycle is longer(4 to 8 weeks in general), the clinical application of gold standard is limited. Tuberculosis could develop in every tissue or organ, and different location of tuberculosis expresses different symptoms when considering structure disparity among tissues or organs.Currently, diagnosis method used in the clinical contains bacteriological examination,immunologic test, molecular biological detection, pathological examination, imagingdiagnosis and so on. Acid fast bacilli smear microscopy acid-fast stain method is the uppermost bacteriological examination in clinical tuberculosis diagnosis and mycobacterium tuberculosis is the major bacteria that needs to detect in the laboratory as well. Nevertheless, positive rate of traditional acid-fast staining method in tuberculosis diagnosis is only 5%.ObjectiveAcid fast bacilli smear microscopy acid-fast staining method has applied in clinical diagnosis for more than 100 years. Acid-fast staining smear microscopy, which doesn’t need too much complex technique and financial support, is a rapid, cheap and specific method for tuberculosis detection. So it has became one of the most widely used tuberculosis detecting examinations all over the world. The WHO recommended developing countries should use the method in the tuberculosis prevention. Recently, a new modified acid-fast staining method made amazing achievement with which the positive rate in the diagnosis of tuberculous meningitis rised from 16.7% to 93.8%. We transplanted this modified acid-fast staining method to the diagnosis of tuberculous proselytism, in order to establish a method, which was simple and fast, has high sensitivity and high specificity in the diagnosis of tuberculous proselytism.MethodsFrom May 2013 to November 2013, the patients with suspected tuberculosis in Xi Jing Hospital of The Fourth Military Medical University, The Tuberculosis Hospital of Shaanxi Province and The Tuberculosis Hospital of Xi’an City, were enrolled as the targeted subject. We kept the serous effusion or lavage fluid. We used conventional acid-fast staining and modified acid-fast staining method to detect acid-fast bacilli. If bacteria was detected, we marked it as the Positive. On the contrary, we marked it as the Negative. We extracted 5ml samples following centrifuging of 15 minutes, dried them and checked sediment using conventional acid-fast staining method. In the modified acid-fast staining method,TritonX-100 was added. We ecstatically compared the difference betweenconventional method and modified method in positive rate for detecting acid-fast bacilli.We retrospectively gathered results of bacteriological culture, pathological examination,diagnostic treatment and T-SPOT TB and compared its positive rate with modified method.ResultsUsing the 100 serous cavity effusion samples from patients with newlydiagnosed tuberculous proselytism, we compared the acid-fast bacilli positive detecting rate between modified method and traditional method: the positive rate of modified method was 34%(34/100), the traditional method was 3%(3/100), the comparative difference was statistically significant(McNemar X2= 6.004, P < 0.001),that is the positive predictive value of positive rate in modified method was higher than traditional method. Two doctors detected acid-fast bacilli respectively in modified method: the observation coincidence rate was 95%, the Kappa value was 89.2%. The modified method had high reliability. In49 samples from patients who were confirmed as tuberculous proselytism, we compared the positive detecting rate in the diagnosis of tuberculous proselytism between the modified method and the traditional method: the positive rate of modified method was59.18%(29/49), the traditional method was 6.12%(3/49), the comparative difference was statistically significant(McNemar X2= 2.204, P < 0.001), that is the positive rate in the modified method was higher than the traditional method. We further performed stratified analysis in above 49 patients, positive rate of modified method was higher than the traditional method: positive detecting rate of modified method and traditional method in28 patients with none of anti-tuberculosis treatment were 71.43%(20/28) and 3.57%(1/28)respectively and the comparative difference was statistically significant(McNemar X2=0.415, P < 0.001); the positive rate of modified method and traditional method in 21 patients with anti-tuberculosis treatment were 42.86%(9/21) and 9.52%(4/21)respectively and the difference was statistically significant(McNemar X2= 2.947, P =0.016). The positive rate of modified method and traditional method in patients who were treated by anti-tuberculosis treatment less than 1 month were 66.67%(26/39) and 7.69%(3/39), and the comparative difference was statistically significant(McNemar X2= 1.625,P < 0.001). In the treatment duration of 14 days or less, the positive rate was 69.4%(25/36), the positive rate in the treatment duration above 14 days was 30.7%(4/13), there was a statistical significance(X2= 5.914, P = 0.015). In the duration of 28 days or less,the positive rate was 66.7%(26/39), the positive rate in the duration above 28 days was 30.0%(3/10), there was a statistical significance(X2= 4.430, P = 0.015).Retrospecting the detecting results of bacteriological culture, pathological examination,diagnostic treatment and T-SPOT TB in above subjects–, we compared all above results with the modified method. The positive rate of bacteric culture was 15.8%(3/19) and the modified method was 26.3%(5/19), there was a statistical significance(X2 = 9.975, P =9.975). The positive rate of the pathologic examination was 77.8%(21/27) and the modified method was 74.1%(20/27),the different was statistically significant(X2 = 0.220,P = 0.220). The positive rate of the diagnostic treatment was 97.9%(46/47) and the modified method was 59.6%(28/47), the different was statistically significant(X2 = 0.693,P = 0.693). The positive rate of T-SPOT TB was 86.0%(37/43) and the modified method was 65.1%(28/43),there was statistical significance(X2 = 0.701, P = 0.701).ConclusionThe authenticity of the modified acid-fast staining method was stronger and the positive rate was higher than traditional method. The Kappa value was high. Not only in the newly diagnostic cases, but also in the confirmed diagnostic cases, the positive rate of modified method was higher than traditional method in tuberculous proselytism. The positive detecting rate of modified method is higher than that of traditional method in different patients who varied from the primary to the recurrent, from the stable to the active, from the treated to the untreated.The comparative difference was not statistically significant among the modified method, pathological examination, T-SPOT.TB and the diagnostic treatment. But pathological examination is often limited by location of puncture and has its flaws.T-SPOT.TB need complex technology and high cost. Diagnostic treatment is time-consuming and is more easily affected by the drug resistance.The modified acid-fast staining have a high sensitivity and specificity, is not strict on the experimental requirement, and its operation is simple and quick, so it is worthy of popularization in the clinical. |
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