ABSTRACT
Objective To research a simple and sensitive K-ras gene mutations detection method in order to be suitable for the routine mutation detection.Methods The corresponding detection locus oligonucleotide probe was designed.By the connection,amplification,labeling and ELISA reaction in probe,the mutation locus genotype was determined by the ELISA reaction detection value.With the six point mutations of G12S,G12R,G12C,G12D,G12A and G12V in 12 codons of K-ras gene as the detection objects,the plasma circulation DNA sample in 72 cases of lung cancer was detected,then the results were compared with those obtained by the direct sequencing.Results Three samples were identified as the G12S,G12R and G12A mutatins by the established method.But no K-ras mutations were detected in the samples by using the direct sequencing,indicating that the direct sequencing had lower sensitivity and was not suitable for the mutation detection of heterogeneous samples such as circulating DNA.Conclusion The simple and sensitive K-ras gene mutation detection method is established and can conduct the routine mutation detection for the heterogeneous samples.
ABSTRACT
Objective To investigate prevalence of resistance genes for β-lactams in clinically isolated multidrug-resistant Acinetobacter baumannii (MDRAB)in a hospital.Methods 22 clinically isolated MDRAB strains were performed antimicrobial susceptibility testing,resistance genes forβ-lactams (TEM,SHV,CTX-M,PER,DHA, IMP ,VIM ,SIM,OXA-23,OXA-24,and OXA-58)in these strains were detected with polymerase chain reaction. Results The resistant rates of 22 isolates of MDRAB to ceftazidime,cefotaxime,cefepime,gentamycin,amikacin, ciprofloxacin,and compound sulfamethoxazole were all 100.00%;to imipenem,meropenem,and cefoperazone/sul-bactam were 50.00%,40.91 %,and 31 .82% respectively,intermediated rates were 31 .82%,36.36%,and 31 .82% respectively.The carriage rates of OXA-23,TEM,IMP ,and PER were 100.00% (n =22),72.73 %(n=16),54.55% (n = 12),and 18.18% (n =4)respectively.Detection results of SHV,CTX-M,DHA,VIM , SIM,OXA-24,and OXA-58 were all negative.Conclusion Carriage of IMP ,TEM,PER,and OXA-23 resistance genes are the major resistance mechanisms of MDRAB to β-lactamase antimicrobial agents in this hospital.
ABSTRACT
Objective To identify an suspected Vibrio cholerae isolated from Xiangyang Central Hospital and characterize the strain in terms of antibiotic resistance and relevant virulence genes.Methods Pathogen identification and susceptibility testing were completed with MicroScan WalkAway 40 Automated Microbiology System.Slide agglutination was used for serotyping. PCR and sequencing technology were employed for 16s RNA gene analysis.PCR technique was used to detect six major viru-lence genes.Results This suspectedVibrio cholerae isolate was confirmed as non-O1 and non-O139 Vibrio cholerae .Suscep-tibility testing results indicated that the strain was sensitive to ampicillin,chloramphenicol,trimethoprim-sulfamethoxazole, and tetracycline.16s RNA gene sequence analysis showed 100% homologous with the registered sequence in National Center for Biotechnology Information database.Virulence genes rtxC and toxR were identified.The other virulence genes such as tcpAET,ctxA,hlyA,and tcpACL were negative.Conclusions This suspected Vibrio cholerae isolate is confirmed as non-O1 and non-O139 Vibrio cholerae .The pathogenic factors may be related to the virulence genes rtxC and toxR.