| Objectives To investigate the epidemic distribution of AB in Chengde in the years of 2011 and 2016,so do the susceptibilities of AB to 15 antibiotics.The transition of susceptibilities were analysed during the 5 years.β-lactamase gene and efflux pump gene were detected,so to discover the mechanism of drug resistance,and set experimental basis for the prevention and therapy of AB infection in Chengde.Methods 104 AB strains and 348 strains were isolated in 2011 and 2016 respectively from 3 hospitals in the city of Chengde.The isolates were classified with VITEK-2 COMPACT auto-micro biological instrument,and the distribution of AB was described according to epidemic terms.The susceptibilities of AB to 15 antibiotics were detected by agar dilution method.PCR was performed to detected β-lactamase gene included OXA-23,OXA-24,OXA-58,VIM and IMP.In additional,efflux pump gene as the followings adeA,adeB,adeC,adeR and adeS was also determined with the same technique.Other than that,PFGE was performed for the homology analysis of isolates.Results 1 Epidemic distribution of AB The incidences of AB infection in 2011 and 2016 were 5.1% and 9.7% respectively,and the difference was statistic significant(P<0.05).The major resource of specimen was sputum both in 2011 and 2016 in Chengde,and the department of ICU was the preponderance Clinic Unit,while people more than 61 year old was inclined to be infected by AB.The positive rates of AB infection in blood increased from 4.8% in 2011 to 8.0% in 2016,and the difference was statistic significant(P <0.05).The positive rates of AB infection in pediatric department from11.5% in 2011 to 15.2% in 2016,and the difference was statistic significant(P<0.05).The positive rates in the population less than 1 year old increased from 5.8% in 2011 to 9.8% in 2016,and the difference was statistic significant(P<0.05).The difference of sex ratio was not statistic significant between the two years(P>0.05).2 Comparisons of susceptibilities of AB to antibiotics Compared to 2011,the drug resistance rates of AB to Polymyxin B and Cefoperazone/sulbatan were not statistic significant in 2016(P>0.05),while the resistance rates of AB to the remain 13 antibiotics were increased from 2011 to 2016 statistic significant(P<0.05).3 The incidences of CRAB,MDR-AB and PDR-AB The incidences of CRAB,MDR-AB and PDR-AB infection were 38.5%,39.4% and 19.2% in 2011 respectively,while their 79.0%,80.7% and 39.1% in 2016 respectively,and the differences between the two years were statistic significant(P<0.05).4 Results of β-lactamase genes detection The most common gene detected was OXA-23 both in 2011 and 2016,it was 90.5% in 2011 and 100% in 2016 respectively,and the difference was statistic significant(P<0.05).The positive rates of VIM were 14.3% and 92.5% in 2011 and 2016 respectively,and the difference was statistic significant(P<0.01).About OXA-58,the data were 0% in 2011 and 28.3% in 2016 respectively,and the difference was statistic significant(P<0.01).OXA-24 and IMP were not detected both in 2011 and 2016.5 Results of MIC reversed by CCCP After treated with pump inhibitor CCCP,the phene positive rates in 2011 were as the follows in order from high to low,Meropenem 95.2%,Imipenem 66.7%,Cefotaxime 61.9%,Gentamycin 28.6%,Levofloxacin 16.7%.While they were Meropenem 95.3%,Imipenem 66.0%,Cefotaxime 61.3%,Gentamycin 29.2%,Levofloxacin 16.0%,respectively in 2016.The differences of reversed MIC were not statistic significant between the two years(P>0.05).6 Results of the efflux pump genes detection The positive rates of the flux pump genes in 2011 were as the follows in order of high to low,adeB52.4%,adeA50.0%,adeS45.2%,adeC42.9% and adeR42.9% in 2011 years.While they were adeB100%、adeA92.5%,adeS86.8%,adeR85.8% and adeC83.0% respectively in 2016,and the difference was statistic significant(P<0.01).7 Results of homology analysis by PFGE The ratios of typeA,typeB and typeC of CRAB in 2011 were 73.8%,21.4% and 4.8% respectively,while the ratios of typeA,typeB,typeC,typeD and typeE of CRAB in 2016 were 41.5%,50.9%,4.7%,1.9%,0.9% respectively.The difference of ratios of typeA and typeB between the two years were statistic significant(P<0.01),while the ratios of typeC and typeD and typeE demonstrated no significant differences between the two years(P>0.05).Conclusions 1 The incidences of AB was observed to be in an increment trendy in Chengde from 2011 to 2016.The major resource of specimen was sputum,and the department of ICU was the preponderance Clinic Unit,while people more than 61 year old was inclined to be infected by AB.2 The drug resistance rates of AB to antibiotics except Polymyxin B and Cefo perazone/sulbatan increasing from 2011 to 2016 in Chengde.3 The incidences of CRAB,MDR-AB and PDR-AB inclined to increase from 2011 to 2016 in Chengde.4 OXA-23,VIM,OXA-58 and flux pump genes might contribute to the increasement of drug resistance in Chengde.5 The prepotent strain of CRAB infection were typeA and typeB during the 5 years.Infections caused by new occurrence typeD,typeE and subtypeB were observed in 2016. |
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