In October 2010,the Department of Medical Administration of the Ministry of Healthy of China published Diagnosis and Treatment Standard of Colorectal Cancer.Since then,the diagnosis and treatment of rectal cancer are under regulation.Standardization of preoperative diagnosis and proper selection of imaging or histopathological examinations are key points in improving the efficacy of individual treatment of patients with rectal cancer.In this article,suggestions from the National Comprehensive Cancer Network (2011 version ),American College of Radiology and College of American Pathologists are analyzed,and the recommendations of imaging and histopathological examinations are highlighted.

Objective To establish and evaluate the method for detection of methicillin-resistant Staphylococcus aureus (MRSA) by the cefoxitin disk diffusion test.Methods The disks with 30 microgramme of cefoxitin and oxacillin recommended by NCCLS were used for the detection of MRSA with PCR by using mecA as the reference.The MIC of cefoxitin to Staphylococcus aureus was also determined.Results Of the 145 test isolates of Staphylococcus aureus,83 isolates showed the mecA-positive by PCR,62 isolates were negative.In cefoxitin disk diffusion tests,82 isolates showed MRSA-positive and 63 isolates were negative.The sensitivity was 98.8% and the specificity was 100%.In oxacillin diffusion tests,the sensitivity was 95.2% and the specificity was 96.8%.Conclusions For the detection of MRSA,the cefoxitin disk diffusion test was consistent with the results by PCR for mecA.The cefoxitin disk diffusion test is easy to be performed and can be used in routine diagnostic works.

Objective To compare the efficacy of transcervical resection(TCRC)and loop electrosurgical excision procedure(LEEP)for the treatment of cervical intraepithelial neoplasia grade I(CINⅠ).Methods A total of 231 CIN I patients were divided into two groups according to their patient number to receive TCRC or LEEP.The resected specimens were sent for pathological diagnosis and human papilloma virus(HPV)-16/18 test.Results No significant difference was found in the operation time[(14.1?2.2)min vs.(13.8?2.1)min],rates of wound infection and cervical stricture[1.7%(2/115)vs.1.7%(2/116)and 0.9%(1/115)vs.1.7%(2/116)],and rates of cure and recurrence [99.1%(107/108)vs.99.1%(108/109)and 0.9%(1/108)vs.0.9%(1/109)] between the TCRC and LEEP groups(t=1.060,P=0.290;?2=0.000,P=1.000;?2=0.000,P=1.000;?2=0.000,P=1.000;?2=0.000,P=1.000).In the TCRC group,the surgical wound was healed in(5.0?0.6)weeks,which was significantly shorter than that in the LEEP group[(5.2?0.7)weeks,t=-2.331,P=0.021].The patients who had severe endocervicitis in both the groups had similar rate of residual endocervicitis[16.7%(2/12)vs.53.8%(7/13),Fisher's test:P=0.097].In both the groups,one patient respectively showed residual lesion after the procedure,in whom HPV-16 and/or HPV-18 were detected.Conclusions Both TCRC and LEEP are effective for CINI.LEEP is easier to master than TCRC.Closed follow-up is essential of the with patients positive HPV-16 or-18.

Objective To compare the therapeutic effects of transcervical resection(TCRC) and loop electrical excision procedure(LEEP) for the treatment of moderate-to-severe chronic cervicitis.MethodsFrom January 2003 to July 2006,totally 520 patients with moderate-to-severe chronic cervicitis were randomly divided into two groups to receive TCRC or LEEP.ResultsThe intraoperative blood loss in the TCRC group was significantly less than that in the LEEP group [(4.2?1.3) ml vs(10.1?4.5) ml,t=-20.310,P=0.000].Whereas,no significantly differences were found in the drainage and bleeding time and cure rates between the two groups [(15.9? 3.7) d vs(16.2? 3.3) d,t=-0.976,P=0.330;and 95.2%(236/248) vs 93.2%(235/252),?2=0.832,P=0.362].ConclusionsBoth TCRC and LEEP are effective for chronic cervicitis.TCRC is superior to LEEP in the surgical outcomes;however the latter is easier to perform than TCRC.

Objective To evaluate the capability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry ( MALDI-TOF MS) for rapid identification of methicillin-resistant Staphylo-coccus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) strains.Methods Twenty-five MRSA and thirty MSSA isolates were collected from the Second Affiliated Hospital of Zhejiang University School of Medicine as the experiment group .Twelve MRSA and twenty-two MSSA clinical strains were isola-ted as the control .All strains were identified by MALDI-TOF MS and the results were further analyzed by ClinProTools 3.0 software.Results Four algorithms including support vector machine (SVM), genetic al-gorithm ( GA) , supervised neural network ( SNN) and quick classifier ( QC) showed similar results in dis-tinguishing MRSA from MSSA isolates .The sensitivity of GA was 100 .0%and the sensitivities of other algo-rithms were all greater than 95.0%.The specificities of GA, SVM and QC were all greater than 90.0%. The areas under the receiver operating characteristic ( ROC) curves of four characteristic peaks at mass-to-charge ratios (m/z) of 3279, 6485, 6555 and 3299 m/z were all greater than 0.9.The virtual gel view showed that the bands generated by MSSA isolates at 3279 , 6485 and 6555 m/z were obviously deeper in color than those generated by MRSA isolates .However , the bands of MSSA isolates at 3299 m/z were appar-ently lighter in color than those of MRSA isolates .83.3%of MRSA and 90.0%of MSSA isolates from the control group were correctly identified by the GA model .Conclusion MALDI-TOF MS could rapidly and accurately identify MRSA from MSSA isolates under the strictly controlled experimental conditions with the advantages of less time-consuming, high sensitivity and high specificity .The accurate identification of MRSA from MSSA isolates could be applied for the prevention and treatment of MRSA infection .

Objective To investigate the linezolid resistance mechanisms and molecular epidemiology of clinical isolates of methicillin-resistant coagulase-negative staphylococci (MRCoNS).Methods Seventeen MRCoNS,including 10 S.capitis,4 S.cohnii,2 S.haemolyticus,and 1 S.sciuri with various levels of linezolid resistance were isolated from intensive care units in our hospital from March to August 2011. Minimal inhibitory concentration (MIC) was determined by E-test method. Pulsed-field gel electrophoresis was performed to analyze the molecular epidemiology.PCRs and DNA sequencing were preformed to investigate the mechanisms of linezolid resistance in MRCoNS.Results Nine S.capitis with linezolid MIC of ＞256 μg/ml were indistinguishable,and another S.capitis with linezolid MIC of 4 μg/ml was closely related.Four S.cohnii with linezolid MIC of ＞256 μg/ml were belonged to the same clonal strain.MIC of linezolid for S.sciuri was 64 μg/ml,and were 4 μg/ml and 6 μg/ml for 2 S.haemolyticus,respectively.A commom G2576T mutation and a novel C2104T mutation were identified in 9 S.capitis with linezolid MIC of ＞256 μg/ml by DNA sequence analysis of domain V of the 23S rRNA gene.cfr gene was deteeted in all staphylococci except a S.sciuri whose 23S rRNA gene contained the G2576T mutation.Conclusion It is the first report of linezolid-resistant clinical isolates of staphylococci in China.Linezolid resistance in MRCoNS is related to the presence of DNA mutation in domain V of the 23S rRNA gene and cfr gene.It's a clonally dissemination of linezolid-resistant MRCoNS in intensive care units of our hospital.

Objective To investigate the molecular epidemiology and mechanism of earbapenem resistance of Serratia marcescens,Klebsiella pneumoniae and Escherichia coli isolates from intensive care units(ICUs).Methods Twenty-one S.marcescens,ten K.pneumoniae and one E.coli isolates with carbapenem resistance or reduced carbapenem susceptibility were recovered from two ICUs in our hospital from April 2006 to Febmary 2007.Pulsed-field gel electrophoresis(PFGE)and enterobacterial repetitive intergenic consensus-PCR(ERIC-PCR)were performed to analyze the molecular epidemiology of isolates.Antibiotic susceptibilities were determined bv agar dilution method.Conjugation experiments were carried out in mixed broth cultures.Plasmid DNA was obtained bv using an alkalinelysis technique and was digested by various endonucleases.Elimination of plasmid from S.marcesceus isolates were performed by repeated SDS treatment.The crude β-lactamase extracts of original isolates and E.coli transconjugants were subjected to isoelectric focusing(IEF);Specific PCRs and DNA sequencing were preformed to confirm the genotype of β-lactamases.Results ERIC-PCR indicated that all S.marcescens isolates belonged to a clonal strain.PFGE indicated that ten K. pneumoniae isolates were indistinguishable or closely related to each other.The MICs of imipenem and meropenero for all isolates were 2 to 8 μg/ml except K.pneumoniae K10(128 and 256 μg/ml).Conjugation studies with E.coli(EC600)resulted in the transfer of reduced carbapenem susceptibility from original isolates(MICs:from≤0.125 μg/ml to 1-2μg/ml).IEF,PCR and DNA sequence analysis confirmed that S.marcescens isolates produced KPC-2(pI of 6.7)and a β-lactamase(pI 6.5).k pneumoniae isolates produced TEM-1(pI 5.4),KPC-2,CTX-M-14(pI 7.9),and a β-lactamase(pI 7.3).E.coli El produced KPC-2,CTX-M-15(pI 9.0),and a β-laetamase(pI 7.3).Only a KPC-2 was detected in E.coli transeonjugants.Plasmid restricfion analysis using EcoR Ⅰ,Hind Ⅲ,and Bcu Ⅰ showed identical restrietion patterns among all E.coli transconjugants.SDS-PAGE and ompK 35/36 gene sequence analysis of OMPs revealed that K.pneumoniae K10 failed to express OmpK36 because of insertional inactivation by an insertion of ISEcp1.Conclusions Carbapenem-non-susceptible S.marcescens.K.pneumoniae and E.coli were epidemic in two ICUs in our hospital.Resistance or reduced susceptibility to carbapenems in these strains is mainly due to production of KPC-2.Presence of KPC-2 combined with porin deftciency result in high-level carbaoenem resistance in K.pneumoniae.The game blaKPC2-encoding plasmid spreads among the three different genera.

Objective To estimate the application for the rapid identification of common clinical bacteria by MALDI-TOF MS. MethodsFour hundred and twenty-six bacteria, including Salmonella spp strains collected from Zhejiang center for disease control and prevention were collected from blood, sputum,secretion and urine in 2nd Affiliated Hospital of Zhejiang University during December 2008 to August 2009. The isolates included 76 gram positive coccus and 350 gram negative bacilli. Species identification was performed with the Vitek system, and serotypes of Salmonella and Shigella were determined by serum agglutination test. 16s rDNA gene of 91 bacteria were amplified by PCR. The RCP products were sequenced. Then the results were compared with the reported sequences from GenBank. All strains were identified by MALDI-TOF MS. Results of three identification methods were compared with each other. Results Among 426 tested isolates, identification results from Vitek system and MALDI-TOF MS for gram positive coccus and 323 out of 350 gram negative bacilli (exception for Salmonella and Shigella spp.),were identical. For 23 Salmonella and Shigella spp. , only 2 Salmonella enterica subsp, enterica serovar Typhimurium were identified the same results by the three methods. Besides, results from Vitek system and serum agglutination test for 1 Salmonella enterica subsp, enterica serovar Typhi, 3 Salmonella enterica subsp.enterica serovar Paratyphi A, 1 Salmonella enterica subsp, enterica serovar Paratyphi B, 1 Salmonella enterica subsp, enterica serovar Enteritidis, and 1 Salmonella enterica subsp, enterica serovar Bovis-morbificans were consistent with that from 16S rDNA gene sequence. Four isolates which were confirmed as S. flexneri by Vitek system and serum agglutination test were identified as Escherichia coli by both 16S rDNA gene sequence and MALDI-TOF MS. ConclusionMALDI-TOF MS could be used for rapid and accurate identification of common clinical bacteria with good repeatabihty, excepting for the Salmonella and Shigella spp.

Objective To investigate mechanisms of carbapenem resistance in Klebsiella pneumoniae. Methods Two carbapenem-non-susceptible Klebsiella pneumoniae Z4 and Z5 isolated from Beijing Hospital in 2008 were investigated. MICs of antibiotics were determined by agar dilution method.Conjugation experiment was carried out in mixed broth cultures. Plasmid DNA preparations were obtained by using an alkalinelysis technique. Elimination of plasmids was performed by repeated SDS treatment. The crude β-lactamase extracts were subjected to IEF. The genotype of β-lactamases were confirmed by PCRs and DNA sequence analysis. Outer membrane proteins (Omps) were isolated and examined by SDS-PAGE.The ompK35 and ompK36 genes were amplified by using PCR and were sequenced. Results MICs of imipenem, meropenem and ertapenem for Z4 and Z5 were 32, 32 and 256 μg/mi, and 1, 1 and 2 μg/ml.Conjugation study with Escherichia coli EC600 resulted in the transfer of significant reduced carbapenem susceptibility from Z4 and Z5 ( MICs increased at least 8-fold). Klebsiella pneumoniae Z4 produced IMP-4 metallo-β-lactamase, TEM-1 and SHV-1 spectrum β-lactamase and Z5 produced IMP-4, TEM-1 and SHV-12 extended-spectrum β-lactamase. E. coli transconjugants of both Z4 and Z5 produced a single IMP-4.Elimination of IMP-4-encoding plasmid from Z5 resulted in carbapenem susceptibility in the isolate,however, Z5 whose IMP-4-encoding plasmid was eliminated exhibited reduced susceptibility to carbapenems ( MICs of imipenem, meropenem and ertapenem were 0. 25 μg/ml,0. 5 μg/ml and 4 μg/ml). Amplification of integron revealed that blaIMP-4 gene of both Z4 and Z5 located within two different class I integrons which were carried on two plasmids with a similar size of approximately 55 000 bp. SDS-PAGE and ompK35/36 genes sequence analysis of Omp indicated that Z4 failed to express OmpK36, because of a nonsense mutation (CAG into TAG) in the ompK36 gene. Conclusion Production of plasmid-mediated metallo-β-lactamase IMP-4 or production of β-lactamase combined with porin OmpK36 deficiency can lead to reduced susceptibility to carbapenems. High-level carbapenem resistance in Z4 is mainly due to production of IMP-4 and the loss of OmpK36.

Objective To evaluate the ability of matrix-assisted laser desorption/ionization time-offlight mass spectrometry (MALDI-TOF MS) in identifying species of Acinetobacter calcoaceticus-Acinetobacter baumannii complex,and investigate the species distribution of Acinetobacter calcoaceticus-Acinetobacter baumannii complex isolated in our hospital.Methods A total of 502 nonduplicate clinical isolates of Acinetobacter calcoaceticus-Acinetobacter baumannii complex were retrospectively collected from the second affiliated hospital of Zhejiang University between January 2012 and July 2012.All strains were re-identified by MALDI-TOF MS and were also verified by sequence analysis of 16S-23S rRNA gene spacer region.Results Among all the 502 strains of Acinetobacter calcoaceticus-Acinetobacter baumannii complex,identificaion results provided by MALDI-TOF MS were A.baumannii (431,85.9％),A.pittii (68,13.5％),A.calcoaceticus (3,0.6％).Sequence analysis of 16S-23S rRNA gene spacer region was used to identify all the 502 strains:403 (80.3％) were identified as A.baumannii,68 (13.5％) as A.pittii,28 (5.6％) as A.nosocomialis and 3 (0.6％) as A.calcoaceticus.MALDI-TOF MS correctly identified all the strains but erroneously identified all 28 strains of A.nosocomialis as A.baumannii,compared with sequence analysis of 16S-23S rRNA gene spacer region.Conclusions MALDI-TOF MS can be used as a fast,simple,reliable and excellently reproducible method to identify members of Acinetobacter calcoaceticus-Acinetobacter baumannii complex at low costs.MALDI-TOF MS is expected to be an ideal technique for routine clinical microbiology testing in the future.