首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 804 毫秒
1.

Background

The anaerobic spirochetes Brachyspira hyodysenteriae and Brachyspira pilosicoli cause diarrheal diseases in pigs. Their fastidious nature has hampered standardization of methods for antimicrobial susceptibility testing. For monitoring of antimicrobial susceptibility wild type cutoff values are needed to define where the wild type distribution of MICs ends and no approved cutoffs are available for Brachyspira spp. In this study antimicrobial susceptibility data for both species (in total 906 isolates) were compiled and analyzed and wild type cut off values for B. hyodysenteriae proposed.

Methods

The MICs of tiamulin, valnemulin, tylosin, tylvalosin, doxycycline and lincomycin were determined by broth dilution in brain heart infusion broth supplemented with 10% fetal calf serum.

Results

The compiled MICs from the broth dilution tests of the B. hyodysenteriae type strain, B78T (ATCC® 27164T), showed that the method yields reproducible results. In an international perspective the frequencies of isolates with decreased antimicrobial susceptibility were low among both B. hyodysenteriae and B. pilosicoli. However, in B. pilosicoli a constant level of 10-15% isolates with tiamulin MICs >4 μg/ml was detected between 2002 and 2010 and in B. hyodysenteriae a gradual increase in tiamulin MICs was seen between 1990 and 2003 although this increase has ceased during the last years. The wild type cutoff values proposed for B. hyodysenteriae are: tiamulin >0.25 μg/ml, valnemulin >0.125 μg/ml, tylosin >16 μg/ml, tylvalosin >1 μg/ml, lincomycin >1 μg/ml and doxycycline >0.5 μg/ml.

Conclusions

The broth dilution method used in this study has over the years generated tightly grouped MIC populations for the field isolates and reproducible results for the control strain B78T and is therefore a suitable antimicrobial susceptibility test method for monitoring of Brachyspira spp. Here we propose wild type cutoff values for six antimicrobial agents for B. hyodysenteriae tested by broth dilution based on MIC distributions and the current knowledge on mechanisms of resistance in this species. There are few studies on antimicrobial resistance mechanisms and MIC distributions in B. pilosicoli but to some extent the cutoff values proposed for B. hyodysenteriae may be applicable also for monitoring of antimicrobial susceptibility in B. pilosicoli.  相似文献   

2.
This study is the first conducted in Spain to evaluate antimicrobial susceptibility of field isolates of Brachyspira hyodysenteriae. One hundred and eight isolates of the bacterium, recovered from different Spanish swine farms between 2000 and 2007, were investigated. The minimum inhibitory concentrations (MIC) of erythromycin, tylosin, tiamulin, valnemulin, clindamycin and lincomycin were determined using a broth microdilution technique. Most of the isolates showed poor susceptibility to erythromycin (MIC90 > 256 μg/ml), tylosin (MIC90 > 256 μg/ml), clindamycin (MIC90 > 4 μg/ml) and lincomycin (MIC90 = 128 μg/ml). Reduced susceptibility to tiamulin and valnemulin was observed with a MIC > 2 μg/ml in 17.6% and 7.41% of the B. hyodysenteriae isolates, respectively. Moreover, a survival analysis permitted the detection of an increasing trend in the MIC values for almost all the antimicrobials used in the treatment of swine dysentery when comparing recent isolates (from 2006 to 2007) with those recovered in earlier years (between 2000 and 2004).  相似文献   

3.
4.
The aim of study was to determine the influence of zinc chelate, valnemulin and it’s combination on Brachyspira hyodysenteriae shedding and morphological changes of colonic mucosa in an experimental model of swine dysentery (SD). The study was performed on pigs coming from a dysentery-free herd. Animals were inoculated by B. hyodysenteriae strain B204. When the clinical signs of SD and B. hyodysenteriae shedding developed, the pigs were divided into four treatment groups. The first group was treated with zinc chelate (250 ml/1000 L in water), second group was given valnemulin in feed at 75 ppm; the third group was given a combination of both and the fourth group was control. The results demonstrated therapeutic effect of valnemulin in pigs with serious SD and did not show therapeutic effect of chelated zinc.  相似文献   

5.
Swine dysentery is a mucohaemorrhagic colitis of pigs caused by infection with Brachyspira hyodysenteriae. The disease can be controlled by treatment with antimicrobial agents, with the pleuromutilins tiamulin and valnemulin being widely used. In recent years, the occurrence of B. hyodysenteriae with reduced susceptibility to these drugs has been increasing. The aim of this study was to determine temporal changes in genetic groups and pleuromutilin susceptibility amongst B. hyodysenteriae isolates from Italy. Multilocus sequence typing (MLST) was performed on 108 isolates recovered from 87 farms in different regions of Italy from 2003 to 2012, and their minimum inhibitory concentrations (MICs) for tiamulin and valnemulin were determined. Logistic regression was performed to assess associations between susceptibility to the two antimicrobial agents and genetic group, year and region of isolation. The isolates were allocated to 23 sequence types (STs), with five clonal clusters (Ccs) and seven singletons. More than 50% of isolates were resistant to both pleuromutilins (MIC >2.0 µg/mL for tiamulin and >1.0 µg/mL for valnemulin). All 10 isolates in ST 83 were resistant; these were first isolated in 2011 and came from nine farms, suggesting recent widespread dissemination of a resistant strain. Significant associations were found between the proportion of pleuromutilin susceptible isolates and the genetic group and year of isolation. Although resistant isolates were found in all Ccs, isolates in Ccs 2 and 7 were over five times more likely to be susceptible than those in the other Ccs. A significant trend in the reduction of susceptibility over time also was observed.  相似文献   

6.
Using three reference strains of Brachyspira hyodysenteriae (B204, B234, B169), one B. pilosicoli (P43/6/78), one B. murdochii (56-150), one B. intermedia (PWS/A), one B. innocens (B256) and ten Korean isolates, PCR-RFLP analysis of DNA encoding 23S rRNA was performed to establish a rapid and accurate method for characterizing porcine intestinal spirochetes. Consequently, B. hyodysenteriae and B. pilosicoli revealed different restriction patterns; however, the other three species shared the same pattern. These findings are not consistent with a prior report. Differences in 23S rRNA gene sequences, between two B. murdochii strains, 56-150 and 155-20, were observed. These results indicate that 23S rRNA PCR-RFLP could be used as an identification method for pathogenic Brachyspira spp. (B. hyodysenteriae and B. pilosicoli) as well as an epidemiological tool for characterizing spirochetes isolated from swine.  相似文献   

7.
With the emergence of “Brachyspira hampsonii” associated with swine dysentery in North America, identification of effective treatments and interventions is a pressing need. Denagard® (tiamulin hydrogen fumarate) Liquid Concentrate 12.5% is approved in the United States for treatment of dysentery caused by Brachyspira hyodysenteriae at 0.006% in the water. In this study, the effectiveness of tiamulin in resolving clinical disease, eliminating viable spirochete shedding, and reducing neutrophilic colitis following infection with either “B. hampsonii” or B. hyodysenteriae was evaluated. Seventy-eight 7-week-old crossbred pigs were divided into three groups [sham-inoculated (n = 18), “B. hampsonii”-inoculated (n = 30), and B. hyodysenteriae-inoculated (n = 30)]. Each inoculum group was divided into three subgroups which received either 0.006% tiamulin, 0.018% tiamulin, or no medication. Both levels of tiamulin resolved clinical disease within 24 h of treatment initiation, eliminated spirochete shedding within 72 h of treatment initiation, and resolved and/or prevented histologic lesions in pigs infected with either Brachyspira spp.  相似文献   

8.
Colonic tissues of gnotobiotic pigs inoculated with Treponema hyodysenteriae, in combination with Bacteriodes vulgatus or Fusobacterium necrophorum or both, were examined by fluorescent antibody (FA), selective culture or histologic methods. Location of the organisms was determined by microscopic examination of frozen sections stained with FA and counterstained with Evans blue, and by examination of formalin-fixed sections stained by the Warthin-Starry method. Good correlation was noted between cultural, FA and histologic detection of T. hyodysenteriae, and between cultural and FA detection of B. vulgatus and F. necrophorum. Bacteriodes vulgatus and F. necrophorum were detected by FA on only mucosal surface epithelium, whereas T. hyodysenteriae was found both on surface epithelium and in the crypts of Lieberkuhn.  相似文献   

9.
《Veterinary microbiology》1998,62(2):163-169
Serpulina strains from pigs were identified using simple tests. The large size of S. hyodysenteriae in stainings from colonic contents and faeces was found useful for the presumptive differentiation of this major pathogenic species from the other Serpulinae. However, this morphological characteristic gets lost upon cultivation. The `ring phenomenon' aided to confirm the strong haemolysis typical for S. hyodysenteriae. The weakly haemolytic species S. innocens, S. pilosicoli, S. intermedia and S. hyodysenteriae could be differentiated with the help of the indole spot test and two or four other simple enzymatic tests. Nearly half of the S. hyodysenteriae strains isolated in Belgium were indole-negative. Such strains have only rarely been reported earlier, and were absent among the strains from other European countries examined.  相似文献   

10.
The aims of this study were to investigate the antibacterial activity of lemongrass oil (LG) and its major components which were citral, geraniol and myrcene, against four strains of clinically isolated bovine mastitis pathogens, including Staphylococcus aureus, Streptococcus agalactiae, Bacillus cereus and Escherichia coli by the broth microdilution method, as well as their activity on S. aureus biofilm formation. Attempts to clarify their mechanisms of action by investigation of the effects on intracellular material leakage and morphological changes of S. aureus DMST 4745 were also made. The results demonstrate that S. agalactiae and B. cereus are more susceptible to LG, citral and geraniol than S. aureus and E. coli. Moreover, they also inhibit S. aureus biofilm formation and exhibit effective killing activities on preformed biofilms. The LG appears to have multiple targets in the bacterial cell, depending on concentration used as well as the amount of its components.  相似文献   

11.
The in vitro antimicrobial activities of aditoprim (AP), a new dihydrofolate reductase (DHFR) inhibitor, trimethoprim (TMP), sulfadimethoxine (SDM), sulfamethoxazole (SMX), and combinations of these drugs against some porcine respiratory tract pathogens were determined by use of an agar dilution method. The minimal inhibitory concentrations (MIC) of these agents were determined twice against Bordetella bronchiseptica (n = 10), Pasteurella multocida (n = 10), and Actinobacillus pleuropneumoniae (n = 20) strains isolated from pigs suffering from atrophic rhinitis or pleuropneumonia. All B bronchiseptica strains were resistant to AP and TMP. The MIC50 values of AP and TMP for P multocida were 0.25 and 0.06 microgram/ml, respectively, and for A pleuropneumoniae, 1 and 0.25 microgram/ml, respectively. The MIC50 values of SDM and SMX for B bronchiseptica were 4 and 1 micrograms/ml, respectively; for P multocida, 16 and 8 micrograms/ml, respectively; and for A pleuropneumoniae, 16 and 8 micrograms/ml, respectively. The investigated combinations of the DHFR inhibitors and the selected sulfonamides had synergism for the A pleuropneumoniae strains; the MIC90 values of the combinations were less than or equal to 0.06 microgram/ml. Potentiation was not observed for the B bronchiseptica and the P multocida isolates. The MIC of the combinations against B bronchiseptica and P multocida corresponded respectively to the concentrations of the sulfonamides and the DHFR inhibitors in the combinations. For A pleuropneumoniae, 2 types of strains were used (25% of serotype 2 and 75% of serotype 9). Type-2 strains had lower susceptibility than type-9 strains to AP and TMP as well as to SDM and SMX (at least a fourfold difference in MIC between the 2 types of strains).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
为红茂草药物的进一步开发和利用,本试验以甘肃平凉地区野生药用植物红茂草为研究对象,采用水蒸气提取、蒸馏萃取(SDE)提取、超临界CO2萃取等3种方法,分别提取红茂草中的精油成分;以GC-MS对其精油进行化学成分分析,并将超临界CO2萃取的红茂草精油采用平板菌落计数法对金黄色葡萄球菌、大肠杆菌和绿脓杆菌进行抑菌活性测定。结果显示,三种提取方法中,水蒸气提取法和蒸馏萃取提取法所得精油为橙黄色,有浑浊,超临界CO2萃取法所得精油为淡黄色,澄清液体。3种方法所得精油均含有24种共同成分,以超临界CO2萃取法最优,其提取率为2.1220%,水蒸气提取法最低,提取率为1.7870%;将超临界CO2萃取的红茂草精油作用于3种供试菌,测定其最小抑菌浓度(MIC)分别为:金黄色葡萄球菌0.2500 g/mL、大肠杆菌0.3000 g/mL,绿脓杆菌0.2600 g/mL,抑菌效果显著。研究结果表明,超临界CO2萃取是提取红茂草精油的最佳方法,通过超临界CO2萃取法提取的红茂草精油对金黄色葡萄球菌、大肠杆菌和绿脓杆菌具有良好的抑菌效果。  相似文献   

13.
Antimicrobial susceptibility testing was conducted with 6 different spirochetal strains (4 strains of Leptospira spp. and 2 strains of Borrelia burgdorferi) against 3 antimicrobial agents, commonly used in equine and bovine practice. The ranges of MIC and MBC of amoxicillin against Leptospira spp. were 0.05-6.25 µg/ml and 6.25-25.0 µg/ml, respectively. And the ranges of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of amoxicillin against B. burgdorferi were 0.05-0.39 µg/ml and 0.20-0.78 µg/ml, respectively. The ranges of MIC and MBC of enrofloxacin against Leptospira spp. were 0.05-0.39 µg/ml and 0.05-0.39 µg/ml, respectively. Two strains of B. burgdorferi were resistant to enrofloxacin at the highest concentration tested for MBC (≥100 µg/ml). Therefore, the potential role of tilmicosin in the treatment of leptospirosis and borreliosis should be further evaluated in animal models to understand whether the in vivo studies will confirm in vitro results. All spirochetal isolates were inhibited (MIC) and were killed (MBC) by tilmicosin at concentrations below the limit of testing (≤0.01 µg/ml).  相似文献   

14.
旨在筛选抗菌效果好的艾纳香油,寻找其抗菌活性物质,分析其对金黄色葡萄球菌抗菌作用。通过对金黄色葡萄球菌、大肠杆菌、铜绿假单胞杆菌、无乳链球菌、白色念珠菌体外抗菌试验筛选不同产源(A1~A5)和自制的艾纳香油(B1~B9、T),采用GC-MS分析主要化学成分,并检测其部分化合物对金黄色葡萄球菌、铜绿假单胞杆菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),采用金黄色葡萄球菌感染小鼠模型研究艾纳香油T对动物的保护作用,测定其对细菌生长及细菌形态的影响。结果表明,艾纳香油B9、T体外抗菌效果最好,金黄色葡萄球菌、铜绿假单胞杆菌对其敏感,MIC值分别为9.77、13.68 μg·mL-1,MBC值分别为19.54、27.35 μg·mL-1;从艾纳香油B5、B9、T中检测出36种共有化学成分,其中,α-葎草烯、蒎烯、芳樟醇类化合物具有一定抑菌活性;不同浓度艾纳香油T溶液均可不同程度抑制小鼠的死亡率,减轻小鼠脾肿大、肾炎性渗出,差异极显著(P<0.01);低浓度艾纳香油T溶液能延迟菌株进入对数生长期,高浓度能杀死细菌,造成菌体不规则凸出及凹陷结构,变形严重,甚至细胞破碎。筛选获得艾纳香油T抗菌活性较好,其对金黄色葡萄球菌的抑制与破坏菌体结构、抑制菌株生长有关,其中,α-葎草烯、蒎烯和芳樟醇类化合物可能是抑菌关键物质,值得进一步开发和研究。  相似文献   

15.
Background – Meticillin‐resistant Staphylococcus aureus (MRSA) and meticillin‐resistant Staphylococcus pseudintermedius (MRSP) infections are increasingly reported in dogs, and these bacteria may be isolated from ear infections. Hypothesis/Objectives – The main aim of the present study was to investigate the in vitro antimicrobial activity of miconazole, polymyxin B and a combination of both against 24 canine MRSA and 50 canine MRSP isolates. The minimal inhibitory concentration (MIC) values of 12 other antimicrobial agents were also determined. Methods – All MIC values were determined according to a broth microdilution assay. Results – Acquired resistance was found to all tested agents, except for linezolid, miconazole and polymyxin B. The MIC values for miconazole and polymyxin B against MRSA were in the range of 4–8 and 8–64 μg/mL, respectively, while the MIC values for miconazole and polymyxin B against MRSP were in the range of 1–2 and 0.25–4 μg/mL, respectively. Using a combination of miconazole and polymyxin B, there was no evidence for enhanced in vitro activity of the combination (i.e. synergy) of both products. Nevertheless, MIC90 values of the combination of these antimicrobial agents and of a commercial product containing both agents were at least 1000 times lower than the concentration present in the commercial product. Conclusions and clinical importance – These results indicate that the topical use of a combination of miconazole and polymyxin B in a 43.5:1 ratio may have potential for the treatment of MRSA‐mediated and MRSP‐associated otitis externa in dogs.  相似文献   

16.
The therapeutic value of antibiotics depends on the susceptibility of the infecting microorganism and the pharmacological profile of the drugs. To assess the value of an antibiotic combination of polymyxin B and miconazole this study examined the in vitro synergistic potential of the two drugs on Gram-negative and Gram-positive bacteria and yeast. Antifungal and antibacterial activity was tested by minimum inhibitory concentration (MIC) of broth macrodilution and urea broth microdilution, by fluorescence microscopy and flow cytometry. Synergism was calculated using the fractional inhibitory concentration index (FICi). With Staphylococcus intermedius as target we found up to an eightfold reduction of the individual MICs when both drugs were combined. However, the FICi was 0.63 suggesting no real interaction between the two drugs. With Escherichia coli, Pseudomonas aeruginosa, and Malassezia pachydermatis as targets the antimicrobial drug combination reduced the MICs of polymyxin B and miconazole from fourfold to hundredfold resulting in FICi between 0.06 and 0.5 which defines a synergistic action. Thus, if polymyxin B and miconazole are combined their effect is greater than the sum of the effects observed with polymyxin B and miconazole independently, revealing bactericidal and fungicidal synergism. Our results indicate a strong therapeutic value for the combination of these antimicrobial agents against Gram-negative bacteria and yeast and a weaker value against Gram positive bacteria for clinical situations where these pathogens are involved.  相似文献   

17.
The gene content of 14 strains of the intestinal spirochaete Brachyspira hyodysenteriae was compared using a DNA microarray. A consistent difference occurred in a block of four genes on the ~36 Kb plasmid, with these being present in six virulent strains and absent in eight strains with reduced pathogenic potential. These genes encoded a predicted radical S-adenosylmethionine domain protein, a glycosyl transferase group 1-like protein, an NAD dependant epimerase and a dTDP-4-dehydrorhamnose 2–5 epimerase: they may be involved in rhamnose biosynthesis and glycosylation. The absence of these plasmid genes in B. hyodysenteriae isolates is predictive of reduced pathogenic potential.  相似文献   

18.
Colistin is an antimicrobial drug of the polymyxin group and COLIVET SOLUTION is an aqueous solution containing colistin sulphate (2 × 106 IU/mL), formulated for oral administration. The target species is the pig, particularly the suckling and post weaning animal. This investigation was undertaken to provide pharmacokinetic and pharmacodynamic data on which to base the selection of dosage rate and interval of the solution for the treatment of porcine colibacillosis.Colistin absorption from the gastrointestinal tract of young pigs, when administered at dosage rates of 25,000, 50,000 and 1,00,000 IU/kg, was slight or absent. The drug was therefore restricted almost entirely to the required site of action. The colistin concentration-time profile within the jejunum and ileum was established, and this enabled determination of the pharmacokinetic variables, maximum concentration (Cmax) and area under curve (AUC) and derivation of the surrogate indices of antibacterial activity, Cmax/minimum inhibitory concentration (MIC) and AUC/MIC through integration of in vivo data with the results of in vitro potency studies for four strains of Escherichia coli.In the in vitro bacterial growth inhibition studies colistin acted by a concentration-dependent killing mechanism. Numerical values for the surrogate parameter AUC/MIC producing bactericidal and eradication effects of colistin against four strains of E. coli were established by PK-PD modeling based on the sigmoidal Emax equation. These data were used to predict a daily dosage regimen for colistin.  相似文献   

19.
The present study was conducted to characterize the in vitro antimicrobial activities of 3 essential oils [oregano, rosemary, and a commercial blend of essential oils (BEO)] against pathogenic and nonpathogenic bacteria and to evaluate their effects on broiler chicken performances. The chemical composition of the essential oils was determined using the gas chromatography interfaced with a mass spectroscopy. The disc diffusion method, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC) were applied for the determination of antimicrobial activities of essential oils. In vivo study, a total of seven hundred fifty 1-d-old male broiler chickens were assigned to 6 dietary treatment groups: basal diet (control; CON), CON + 44 mg of avilamycin/kg (A), CON + 100 mg of rosemary essential oil/kg (ROS), CON + 100 mg of oregano essential oil/kg (OR), CON + 50 mg of rosemary and 50 mg of oregano essential oils/kg (RO), and CON + 1,000 mg of BEO/kg (essential oil mixture, EOM). The essential oils isolated from rosemary and oregano were characterized by their greater content of 1,8-cineole (49.99%) and carvacrol (69.55%), respectively. The BEO was mainly represented by the aldehyde (cinnamaldehyde) and the monoterpene (1,8-cineole) chemical groups. The results of the disc diffusion method indicated that the rosemary essential oil had antibacterial activity (P ≤ 0.05) against only 3 pathogenic bacteria, Escherichia coli (8 mm), Salmonella indiana (11 mm), and Listeria innocua (9 mm). The essential oil of oregano had antimicrobial activities (P ≤ 0.05) on the same bacteria as rosemary but also on Staphylococcus aureus (22 mm) and Bacillus subtilis (12 mm). Oregano essential oil had greater (P ≤ 0.05) antimicrobial activities against pathogenic bacteria than rosemary essential oil but they had no synergism between them. The BEO showed an increased antimicrobial activity (P ≤ 0.05) against all studied bacteria (pathogenic and nonpathogenic bacteria) except for Lactobacillus rhamnosus. The supplementation of the basal diet with avilamycin or essential oils improved (P ≤ 0.05) broiler chicken BW, BW gain, and G:F compared with the CON diet. There were no differences in growth performances among birds fed A, ROS, OR, RO, or EOM diets. In general, essential oils contained in rosemary, oregano, and BEO can substitute for growth promoter antibiotics. Although the 3 essential oils had different antimicrobial activities, they exhibited the same efficiency in broiler chickens.  相似文献   

20.
The demand for foods that are free of pathogens and chemical residues has increased interest in the use of plant-based products as natural antimicrobials. Essential oils (EO) from plants are natural compounds that have been shown to have antimicrobial properties against food-borne pathogens. The objective of the current study was to determine the ability of various concentrations of 4 selected EO to inhibit Salmonella enterica (3 different serovars and a cocktail of all 3) and Campylobacter (2 strains of Campylobacter jejuni, one strain of Campylobacter coli, and a cocktail of all 3). The disc diffusion method was used to screen the oils of thyme, orange, rosemary, and clove oil. The minimum inhibitory concentration or minimum bactericidal concentration of the EO was determined using a 2-fold broth dilution method at concentrations ranging from 0.0008 to 1.000% (vol/vol). Two independent experiments were performed. Zones of inhibition (ZI) were expressed in millimeters and concentrations were expressed in percentages. All the oils demonstrated antibacterial activity against the strains tested. However, thyme oil demonstrated the strongest inhibitory activity than other oils against Salmonella (ZI of 18.5 mm). In general, Campylobacter was more susceptible to the antibacterial activity of EO, with plates containing thyme or clove oil showing no growth. Orange oil was also highly effective on Campylobacter, with a mean ZI of 17.5 mm. The least expensive treatment effective against both Salmonella and Campylobacter was a combination of 100% concentrations of thyme and orange oil combined on a 50:50 proportion. Tested on the same strains of bacteria, the thyme-orange combination (TOC) had a mean ZI of 20.5 mm for Salmonella and 21.3 mm for Campylobacter. Thyme-orange combination demonstrated a synergetic effect against Salmonella, but no such effect was noticed for Campylobacter. On average, 0.14% TOC was required to inhibit both pathogens. Hence, TOC can be considered as a potential antimicrobial for future studies on food systems.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号