Objective To develop a method for rapid and accurate detection and identification of bacterial pathogens directly from body fluid specimens and to evaluate its application in clinical laboratory.Methods Bacteria DNA was extracted from 205 body fluid specimens with column-based kit,and the high variable V1 and V3 regions of bacterial 16S rRNA gene were amplified with broad-range primers.Amplicons were analyzed by pyrosequencing and the generated sequences were searched in the bacterial identification database.Traditional culture-biochemical method was also used for these specimens and the results were taken as the golden standard.SPSS 11.0 was used to calculate the sensitivity,specificity,false positive/negative rate,positive/negative predictive value and positive/negative likelihood rate of pyrosequencing method.Results The positive rate of bacteria culture was 39.5％ (81/205),among which 71 were infected with single bacterium,and 10 were infected with two species of bacteria.Compared with the culture identification results,pyrosequencing had a 100.0％ (71/71) concordance when applied to detect and identify bacterial pathogens from specimens with single specie bacterium infected.To specimens with two species bacteria infected,7 out of 10 specimens were in concordance with the culture identification results.Besides,pyrosequencing detected 10 positive specimens and identified bacterial pathogens infected in the 124 culture-negative specimens.Taken bacteria culture as the standard method,the sensitivity of pyrosequencing for identifying bacterial pathogen in body fluid was 100.0％,and with a specificity of 91.9％,the false positive rate was 8.1％,the false negative rate was 0.0％,the positive predictive value was 89.0％,the negative predictive value was 100.0％,and the positive and the negative likelihood rate were 12.4 and 0,respectively.Conclusion Pyrosequencing can be used to detect and identify bacterial pathogens directly from body fluid specimens with the advantages of rapidity,high sensitivity,high accuracy and high throughput.

BACKGROUND: The pathological characteristics of pulmonary interstitial fibrosis are the proliferation of a large number of fibroblasts and the increasing deposition of matrix collagen that takes the place of normal lung structure. Fluvastatin can inhibit the proliferation of fibroblasts and many other cells.OBJECTIVE: To investigate the effects of fluvastatin in inhibiting the proliferation of rat lung fibroblasts cultured in vitro and its influence on bleomycin-induced pulmonary fibrosis and ventilation function.DESIGN: A randomized controlled trial.SETTING: Department of Respiratory Diseases, Xijing Hospital, Fourth Military Medical University of Chinese PLA; Teaching and Research Section of Pathology, Department of Basic Medicine, Fourth Military Medical University of Chinese PLA; Research Institute ofOrthopedics, Xijing Hospital,Fourth Military Medical University of Chinese PLA.PARTICIPANTS: The study was conducted in the laboratory of Department of Respiratory Diseases, Xijing Hospital of Fourth Military Medical University of Chinese PLA from January to December 2001. Thirty-one healthy adult male Sprague-Dawley(SD) rats of grade Ⅰ were selected in this study.INTERVENTIONS: The fibroblasts derived from the lung normal of one rat were cultured in vitro in media containing fluvastatin. The effect of fluvastatin on the growth curve and the effect of its different concentrations(0, 1 × 10-7,1 ×10-6, 1 ×10-5, 1 ×10-4, 1 ×10 3and 1 ×10-2 mol/L, fluvastatin of 0 mol/L was taken as the blank control group) in inhibiting the cultured cells were observed with MTT colorimetry. The effect of fluvastatin on the division index of the fibroblasts was analyzed by direct cell counting Hydroxyproline colorimetry was used to detect the influence of fluvastatin on the collagen secretion in the media. The other 30 SD rats were divided into six groups: normal control group, bleomycin-induced group and fluvastatin-treated groups(TH 1,TE1, TH15 and TL15 groups) named according to the date of giving fluvastatin,i. e. the 1st day and the 15th day, after the rats were given bleomycin A5. All the rats were killed 28 days later. The number of fibroblasts, the thickness of alveolar wall and the area of mesenchyma in lung tissue were measured by HE staining. The extracellular matrix and collagen in lung tissue were observed by Masson and sirius red staining, and hydroxyproline in lung tissue homogenates was measured.MAIN OUTCOME MEASURES: Fibroblast growth curve and division index of rat lung, hydroxyproline in the media and lung tissue homogenates,number of fibroblasts and the thickness of alveolar wall, the area of mesenchyma, extracellular matrix and collagen contents in lung tissue.RESULTS: Fluvastatin could inhibit the proliferation of the rat lung fibroblasts cultured in vitro(t=4.20 to 17.52, P < 0.01), and its inhibitory effect was increased with the increased dose of fluvastatin, which showed a dose-dependent effect. The 1 × 10-4 mol/L fluvastatin could completely inhibit the proliferation of the cultured cells, and the A490 value from the 2nd day on the fibroblasts by MTT colorimetry was not insignificantly different from those on the 1st day( P > 0.05) . The division index of the fibroblasts and secretion of collagen were obviously decreased by fluvastatin( t = 8. 037,P <0.01; t =3.99 to 10. 84, P <0.05 or P <0.01). In vivo, the number of fibroblasts, the thickness of lung alveolar wall, the area of mesenchyma and the content of hydroxyproline in lung tissue were significantly higher in bleomycin group than in control group( t =4. 62 to 11.93, P < 0. 01), while those in the fluvastatin-treated groups were lower than those in bleomycin group in different degrees( t = 2.69 to 7.65, P < 0.05 to 0.01 ) . The distribution of extracellular matrix and types Ⅰ and Ⅲ collagen in lung tissue were obviously increased in bleomycin group as compared with that in control group, but decreased in different degrees in fluvastatin-treated groups.CONCLUSION: Fluvastatin can significantly inhibit the proliferation of rat lung fibroblasts in vitro, suggesting that it may be an effective drug for pulmonary fibrosis. Treatment at earlier stage is more effective than at advanced stage.