| Bacterial resistance is a particularly difficult problem in clinical treatment.To alleviate the resistance of bacteria,it is necessary to explore more preventive and therapeutic measures from its mechanism.Many studies have explored the mechanism of bacterial resistance,but the molecular mechanism of Escherichia coli resistance has not been fully elucidated.This article uses E.coli MG1655-derived drug-resistant strains that have been obtained in the laboratory,named Amp-R,Cam-R,and Gen-R strains,which are resistant to ampicillin,chloramphenicol,and gentamicin,respectively.Through proteomics and other technologies,the resistance-related genes were screened,and the cross-resistance and accessory sensitivity of drug-resistant strains were analyzed.It was found that the Amp-R strain was more resistant to ?-lactam cefoxitin and more sensitive to rifampicin;the Cam-R strain was more resistant to tetracycline and ciprofloxacin,and was more resistant to fosfomycin It is more sensitive to rifampicin;Gen-R strains are more resistant to aminoglycoside kanamycin and neomycin,and are more sensitive to rifampicin,tetracycline and ciprofloxacin.The results indicate that drug-resistant bacteria are prone to cross-resistance to the same kind of antibiotics,and susceptible to subsidiary susceptibility to different kinds of antibiotics.Proteomics analysis found that Amp-R strain had 148 protein expression up-regulated and 150 protein expression down-regulated;Cam-R strain had 279 protein expression up-regulated and 269 protein expression down-regulated;Gen-R strain had 382 protein expression up-regulated and 366 protein expression down-regulated.Differentially expressed proteins are mainly involved in the metabolic processes related to amino acid metabolism,antibiotic biosynthesis and ribosome assembly.The differentially expressed proteins of Amp-R strains are mainly related to amino acid metabolism;the differentially expressed proteins of Cam-R and Gen-R strains are mainly related to the biogenesis of ribosomes.In addition,comparative analysis of transcriptome and proteomics of the three drug-resistant strains was conducted to explore the consistency and differences between the two,and found that the differentially expressed genes and differentially expressed proteins of the Amp-R strains are both related to the biosynthesis of amino acids;The differentially expressed genes and differentially expressed proteins of Cam-R strains are both related to antibiotic biosynthesis;the differentially expressed genes and differentially expressed proteins of Gen-R strains are both related to antibiotic biosynthesis.Compared with wild-type strains,in transcriptome and proteomics analysis,the up-regulated genes are pst S,nfs A,kdg K,kdp E,tor R,mlt F,coh E,ybh Q,pli G,acr Z,ybj C,dml R,dml A,srl A,srl B,srl E,srl D,fnr,kdp A and kdp D total 20.q RT-PCR detection revealed that the m RNA levels of the above genes were all up-regulated.Overexpression of pst S,nfs A,kdg K and kdp E in wild-type strains produced certain resistance to Gen,and overexpression of tor R was more sensitive to Gen.In transcriptome and proteomics analysis,there are 11 genes down-regulated in expression of glt I,mdt I,yce K,din G,ybg S,aro G,ycf J,gad B,lys C,fru B and fru K.q RT-PCR technology detected the m RNA of these genes.The levels are all down.The one-step inactivation method was used to delete genes from the wild-type strains to construct deletion mutants.Analysis found that ?glt I,?yce K,?din G and ?mdt I had certain resistance to Gen,and ?ybg S was more sensitive to Amp,Cam and Gen.In summary,overexpression of pst S,nfs A,kdg K and kdp E genes and deletion of glt I,yce K,din G and mdt I genes can make wild-type strains resistant to Gen.The results showed that pst S,nfs A,kdg K,kdp E,glt I,yce K,din G and mdt I genes and their products are related to the resistance of E.coli.However,there is no research report on the relationship between the kdg K,mdt I,yce K,din G and ybg S genes and bacterial resistance,and the mechanism needs to be studied in depth. |
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