Study Of ESB Ls-producing Escherichia Coli's Porin And Antibiotic Application In Children

Objective: Escherichia coli is the main pathogen causing abdominal infection in children.In recent years,with the extensive application of antibiotics,the production of extended-spectrum ?-lactamase(ESBLs)Escherichia coli's detection rate is rising.It has been shown that the decrease in membrane protein expression is associated with drug resistance in Escherichia coli,but there has no research between the concrete expression quantity of membrane porin and the occurrence of drug resistance.In this study,we retrospectively analyzed the detection rate of ESBLs Escherichia coli and its resistance to common antibiotics in children with abdominal infection from Tianjin Children's Hospital from 2010 to 2016.Beyond that,we also analyzed the effects of different concentrations of ceftriaxone,oxytocin and imipenem on the growth and reproduction of ESBLs-positive Escherichia coli which were sensitive to oxygen cephalosporins.At last,we measured the expression levels of membrane protein Omp F and Omp C in ESBLs-positive Escherichia coli under different concentrations of oxygen cephalosporium,in order to investigate the correlation between membrane protein expression and drug resistance.Methods: We examined the specimens from abdominal infection of children which came from Tianjin Children's Hospital from 2010 to 2016.VITEK 2 COMPACT60 Automatic Microbiological Apparatus was used to identificate the strain and test the drug sensitivity.We chose 30 ESBLs-sensitive Escherichia coli,which were sensitive to oxygen cephalosporium,using ceftriaxone,oxytocin and imipenem at different concentrations(MIC value,1 / 2MIC value,1 / 4MIC value,1/8MIC value)and different times(0h,12 h,24h,36 h,48h,60h)on these Escherichia colis,and then counted the live bacteria,determinated the MIC value and draw the bacterial growth curve;using oxytocin of different concentrations(MIC values,1 / 2MIC value,1 / 4MIC value,1/8MIC value)on the 30 strains of Escherichia coli,then detected the expression levels of membrane protein Omp F m RNA and Omp C m RNA at 6h,12 h,24h,36 h,48h and 60 h by RT-PCR.Results: 1.There was a total of 1349 Escherichia coli were isolated and cultured from Tianjin Children's Hospital(2010-2016)of children with abdominal infection in clinical.The compositional ratio of ESBLs-positive Escherichia coli is as follows: 25.10%,21.01%,20.00%,29.89%,31.03%,33.04%,32.33%.After the line × column chi-square test,the results suggest: there were significant differences in the detection rate of ESBLs-positive Escherichia coli in children with abdominal infection from 2010 to 2012 and 2013 to 2016(P <0.05),and the detection rate showed a rising trend;From 2010 to 2016,the resistance rates of ESBLs-positive Escherichia coli to ampicillin,ceftriaxone,cefazolin,cefotaxime and cefuroxime were greater than 90%,the resistant rates of amikacin,levofloxacin,nitrofurantoin,imipenem,meropenem and piperacillin / tazobactam were 0% to 5%,while the resistance rate of other antimicrobial agents was 9% ~ 86.6%;there was a significant difference in the resistance rate of ESBLs-positive Escherichia coli to cephalosporin from 2010 to 2012 compared with the resistance rate from 2013 to 2016(P <0.05),and the detection rate showed a rising trend;The resistant rate of ESBLs-negative Escherichia coli to ampicillin,gentamicin and cotrimoxazole was 36.1% ~ 78.4%,and the resistance to other antimicrobial agents was 0% to 25.9%.2.High concentrations(MIC value,1 / 2MIC value)of ceftriaxone in the first 36 hours on the Escherichia coli have a certain antibacterial effect,but after 36 hours,the growth rate of Escherichia coli increased significantly while the low concentrations(1 / 4MIC value,1 / 8MIC value)of ceftriaxone on Escherichia coli antibacterial effect is not obvious;About 83% of Escherichia coli in different concentrations of oxygen,high concentration of oxygen cephalosporins has the obviously antibacterial effect,while in the remaining 17% of Escherichia coli,the high concentrations(MIC value,1 / 2MIC value)of the action group's antibacterial effect was lower than the low concentrations group after 48 hours,and the growth rate of Escherichia coli was even faster than that of the control group without antibiotics;The concentration of imipenem has a significant antibacterial effect,and with the concentration of imipenem increased,antibacterial effect is more obvious.3.The expression of Omp F m RNA and Omp C m RNA in 83% of Escherichia coli did not change significantly;The expression of Omp F m RNA and Omp C m RNA in other 17% Escherichia coli was reduced at high concentrations(MIC value,1 / 2MIC value)after 48 h,but the expression of Omp F m RNA and Omp C m RNA did not change significantly at the low concentrations(1 / 4MIC value,1/8MIC value).Conclusion: 1.The detection rate of ESBLs-positive Escherichia coli is increased,and showed a high resistance rate to commonly used antibiotics.For children with ESBLs-positive strains,the antibiotics available were only cephalosporin and carbapenem antibiotics,but the resistance rate of ESBLs-positive Escherichia coli to cephalosporins was also increasing.Clinical work should be based on drug susceptibility test results to reduce the production of resistant strains.2.The clinically isolated ESBLs-positive Escherichia coli is generally resistant to cephalosporin antibiotics,cephalosporin can be used as first-line drugs.But some of the ESBLs-positive Escherichia coli(about 17%)had a decrease in the antibacterial activity at a certain concentration(MIC value,1 / 2MIC value)after 48 h,then Escherichia coli produce resistance.So in the course of clinical medication,we should strengthen the detection of drug-resistant strains,and replace the antibiotic timely.3.Some of the ESBLs-positive Escherichia coli(about 17%),which were sensitive to cephalosporins,had a resistance to cephalosporins at a certain concentration(MIC value,1 / 2MIC value)after 48 h,and it is relatedto Omp F and Omp C's low expression.When the Omp F and Omp C expression levels were reduced to 0.592 and 0.232,we should replace the antibiotics.Replace carbapenem antibiotics as soon as possible can reduce the suffering of children and shorten the hospital stay,more importantly,it can reduce the variation of drug-resistant bacteria.