| Objective:Pseudomonas aeruginosa(PA)is an important pathogen of nosocomial infection,which often caused severe infection including lung and postoperative wound etc.Because of its powerful bactericidal effect,aminoglycoside antibiotics are often used as beta-caprolactam antibiotics to treat severe gram-negative bacterial infections in the clinic.In recent years,PA has the trend of multi-drug resistance,so the study of its the characteristics and mechanisms of drug resistance is particularly critical.In this paper the clinical drug-resistance characteristics of PA strains was reviewed from 2014 to2016 in some hospital in northern Anhui province,and the drug resistance genes of aminoglycoside antibiotics was determined.To further explore the mechanism of the external pump of aminoglycoside PA,the homologous analysis was carried out by ERIC-PCR to provide the theoretical basis for the rational use of antibiotics and the prevention of the epidemic and spread of clonal strains.Method:1.813 strains of Pseudomonas aeruginosa were collected from Jan 2014 to Dec 2016 in a comprehensive hospital.According to the national clinical practice and CLSI 2016drug sensitive implementation standards,the strains were identified by French biomerieux company’s Vitek 2 Compact automatic Microbiological Analyzer and drug susceptibility test was performed.The drug sensitive result was conducted by the paper diffusion method(K-B method).Statistical analysis was performed by WHONET 5.6software with Chi-Square(χ~2)test.The distribution of the clinical infection and drug resistance of PA strains in this area were explored.2.54 strains of aminoglycoside-resistant PA strains were screened,and 16aminoglycoside-Modified enzymes(AMEs)and five 16S rRNA methylation genes were detected by PCR method.The gene types of aminoglycoside-resistant PA strains in local area was studied.3.The external pump phenotype of 54 strains of aminoglycoside-resistant PA strains were screened by synergistic test of MC207110 Paβn combined with gentamicin and amitriptyline amikacin.4.The homologous genotype of 54 aminoglycoside-resistant PA strains was analyzed by ERIC-PCR technique,and the corresponding clinical data were used to analyze the disease.Results:1.From 2014 to 2016,the proportion of PA isolates in a hospital was 9.2%,8.1%and8.9%,respectively.The multiple drug-resistant strains(MDR)were the main clinical isolates of PA,and there was no significant increase in the drug-resistant strains(XDR).The main source of the specimen was sputum,and the clinical distribution was mainly in ICU.The results of drug susceptibility showed that PA was significant in the change of drug resistance rate of 11 kinds of drugs(P are all<0.05),The drug resistance rate of most antibiotics decreased markedly in 2015 compared with 2014,but there was another fluctuation between 2015 and 2016.The preferred drug for PA is piperidine piperacillin/tazobactam,ceftazidime,gentamicin and tobramycin.The drug resistance rate in 2016 was between 12.2%~28.5%.PA’s secondary drug’s resistance rate range is10.9%~32.1%.Aminoglycoside-resistant PA is resistant to beta-caprolactam,carbon-penicillium and quinolone antibiotics,but it is sensitive to the third and fourth-generation cephalosporins.2.The main genes of PA resistance to aminoglycoside antibiotics are 5 kinds of AMEs genes and 2 kinds of 16S rRNA methylation enzyme genes.The 5 kinds of AMEs genes including ant(3’’)-I、aac(3)-IIc、ant(4’)-Ia、aac(6’)-Ib and ant(2’’)-Ia,and then,2 16S rRNA methylation enzyme gene including rmtB and armA.3.The synergistic trials of 54 strains of aminoglycoside-resistant PA with one external pump inhibitors combined with gentamicin and amikacin was positive.4.54 strains of aminoglycoside-resistant PA ERIC-PCR showed 14 types of clones,among them,type 1 has 13 strains,type2 and type11 each have 9 strains,which mainly occurred in ICU Ward.Conclusion1.From 2014 to 2016,the detection rate of MDR-PA in a hospital was significantly elevated,and the resistance of aminoglycoside-type PA was serious,so the rational use of antibiotics should be strengthened.2.AMEs and 16S rRNA methylation is one of the main reasons for the high drug resistance of PA to aminoglycoside antibiotics in the region,and the mechanism of the drug resistance has the outer drain pump system.3.In this experiment,some strains of aminoglycoside PA were highly homologous,and the possibility of cloning spread occurred in individual departments.Therefore,it is necessary to control the spread of MDR to prevent nosocomial infection. |
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