ABSTRACT
Objective The purpose of this study was to compare and develop the method for identification of Non-tuberculous Mycobacteria (NTM) using matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS),and evaluate the feasibility,accuracy and repeatability of MALDI-TOF MS to discriminate NTM.Methods Fifteen clinical strains were collected from January to March in 2012 and 68 environmental strains were retrospectively collected from 2011 to 2012.A protocol for sample pre-treatment and protein extraction was developed and utilized it to identify clinical and environmental isolates.The results from 16 s rRNA sequencing were served as control.Results Method A was more effective in protein extraction.Although all the three methods got the same species result,a total of 83 strains belonging to 10 distinct species grown in Middle brook 7H10 media were analyzed.All members of the NTM were identified accurately at the genus level and 80.7％ (67/83) of strains could be identified at the species level.Six strains were identified at the complex level.81.9％ (68/83) of NTM got high spectral scores.The identification of cultured colony could be completed in 1.5 hours.And it had good reproducibility.Conclusion MALDI-TOF MS can be used as a rapid and accurate method for identification of Mycobacteria in clinical microbiology laboratories,implying its good application prospects.
ABSTRACT
Objective To investigate the physiological state of L. pneumophila in biofilm. Methods Genes previously identified as good markers for the transmissive and replicative phases of the L. pneumophila life cycle during growth in Acanthamoeba castellanii were examined for their expression fold change in the sessile cells as compared to planktonic cells using real-time RT PCR. Results Mature L. pneumophila biofilms were formed at 37t in 75 cm2 cell culture treated flasks for 18 days. The ratio of gene (mip, flaA and fliA) expression in post-exponential cells compared to exponential cells is 0. 53, 4. 45 and 3. 67. The exponential phase cultures display replicative traits and post-exponential bacteria express transmissive factors. The ratio of gene (mip, flaA and fliA) expression in sessile cells compared to exponential cells is 4.42, 5.24 and 16.21, while the sessile cells compared to exponential cells is 8.39, 1. 18 and 4. 43, respectively. Conclusion The violence gene expression of L pneumophila in biofilm is unique.
ABSTRACT
OBJECTIVE To compare the difference of Pseudomonas aeruginosa(PAE) biofilms formation in different conditions including incubated time,temperature,attaching materials,and flowing speed.METHODS PAE biofilms were established in a chemostat-coupled MRD and detected with the method of viable bacteria counting.The number of CFU/disc was measured in different culture time(8h,24h or 72h),different temperature(23℃ or 37℃),different adherent materials(glass or silicone),different flow velocities(30ml/h or 90ml/h) and different culture media(M63 medium,M-H croth or LB broth).RESULTS Keeping the other conditions invariable,the log10CFU/disc of viable bacteria in 8h,24h or 72h biofilms were 4.01?0.26,4.59?0.49 or 5.20?0.47,respectively(P
ABSTRACT
Objective To observe the effect of Ceftazidime on the early and mature Pseudomonas aeruginosa biofilm bacteria. Method The early and mature PA biofilm were formed through the chemostat combined Robbins device. Then 64 ?g/ml Ceftazidime was applied to the early and mature PA biofilm bacteria for 24 hours respectively. Scanning electronic microscope(SEM) was used to observe the effect of Ceftazidime on early and mature biofilm. The difference between the viable bacteria in early and mature biofilm was analyzed by statistical method. Result 24 hours after Ceftazidime was added, Pseudomonas aeruginosa in early biofilm was killed on the whole while there were still numbers of bacteria in mature biofilm. Statistical analysis demonstrates a great variance in viable counts. Conclusion Pseudomonas aeruginosa in mature biofilm is more tolerant to antibiotics than that in early biofilm.
ABSTRACT
Objectives: In this study,we evaluated the influence of different nutritional support routes and nutrients on the intestinal barrier function and bacterial translocation in rats with gut I/R injury. Methods: Sixty male Sprague Dawley rats were made ischemic by clamping the superior mesenteric artery for 30 minutes and were divided randomly into four groups of fifteen animals each,i.e.standard parenteral nutrition (PN),gln enriched TPN (G PN),common enteral nutrition (EN),and enteral immunonutrient (IEN) groups. All the rats received isocaloric nutrition support for seven days.Rats were killed after 7 days'nutrition support.Spleen,liver,mesenteric lymph nodes (MLN),and blood samples were collected for bacterial culture. Endotoxin levels in plasma were also measured.The permeability of intestine mucosa was assayed by D lactate level in plasma.The small intestine was removed for studies.Mucosal thickness,villous height,crypt depth and villous surface area were determined.The gut immune barrier function was evaluated by the immunohistochemical staining method. Results: Atrophy occurred in small intestinal mucosa in PN group.The mucosal thickness,villous height,crypt depth and villous surface area were decreased significantly in PN group compared with other groups ( P