Clinical Distribution Of CTX-M Type ESBLs Multi-drug Resistant Escherichia Coli.

Objective Toinvestigate the susceptibility of extended-spectrum β-lactamase-producing Escherichia coli(E.coli)to common antibiotics.To discuss the distribution of CTX-M multi-drug resistant ESBLs positiveE.coli.Method: 1.The Kerby-Bauer disk diffusion:Determinating the resistance of 153 strains to β-lactam,aminoglycosides and fluoroquinolones.The National Committee for clinical Laboratory Standards was standard.ESBLs-positive E.coli were selected.2.PCR technique: The total volume of the PCR reaction was 25ul: 10 ul of Template,1ul of primer 1,1ul of primer 2,12.5ul of 2 x Taq PCR MasterMix,0.5ul of ddH2 O.Amplification was carried out as follows : initial denaturation at 94℃ for 3min and denaturation at 94℃ for 30 s,annealing at 55 ℃ for 30 s and extension at 72 ℃ for 30 s,amount to 30 cycles,and a final step of 72℃ extension again for 5min.PCR reaction products were sent to Sangon for sequencing.Results: 1.The results of susceptibility test: The isolated E.coli had a different degree of resistance to β-lactamases,aminoglycosides,and fluoroquinolones.Sensitive strains were 12(7.84%),single resistant strains were 32(20.92%),double resistant strains were 43(28.10%),multi-drug resistant strains were 66(43.14%).ESBLs positive strains were 92 strains(60.13%),Single resistance strainswere 3(3.26%),double resistance strains were 30(32.61%),multi-drug resistant strains were 59(64.13%).2.BlaCTX-M results: 86 strains were detected blaCTX-M.BlaCTX-M-1 was detected in 57 strains(61.91%),blaCTX-M-9 was detected in 54 strains(58.70%),blaCTX-M-8was detected in 9strains(9.78%),blaCTX-M-2 and the blaCTX-M-25 were not detected.The detection rates of blaCTX-M-1,blaCTX-M-9 and blaCTX-M-8 were 58.82%,41.18% and 5.88% in multi-drug resistant strains of urinary system.The detection ratesof blaCTX-M-1,blaCTX-M-9 and blaCTX-M-8 were 55.56%,66.67% and 22.22% in multi-drug resistant strains of respiratory system.The detection rates of blaCTX-M-1,blaCTX-M-9 and blaCTX-M-8 were 85.71%,42.86% and 14.29% in multi-resistant strains of pleural effusion.The detection rates of blaCTX-M-1,blaCTX-M-9 and blaCTX-M-8 were 73.07%,50% and 7.69% in multi–drug resistant strains of other types.Conclusion:1.ESBLs positive strains of isolated E.coli arecommon,multiple-drug resistantESBLs positive strains account for 64.13%.2.The detection rate of blaCTX-M in ESBLs positive strainswas 93.48%.BlaCTX-M-1 is the mostfrequent type,followed by blaCTX-M-9.BlaCTX-M-8 is found with blaCTX-M-1 and / or blaCTX-M-9.BlaCTX-M-2 and blaCTX-M-25 are not detected.3.The frequent CTX-M genotypes of the multi-drug resistant ESBLs positive strains are blaCTX-M-1 and blaCTX-M-9.4.The detection rate of blaCTX-M-1 in the General Surgery ward,hepatobiliary surgery ward,gastrointestinal surgery ward,nephrotic ward,respiratory ward is high.The detection rate of blaCTX-M-9 gene in urology Surgery ward and blood ward is also high.