| BackgroundAcinetobacter baumannii(Ab)is a non-fermenting gram negative bacilli.The catalase test is positive and oxidase negative.As an opportunistic pathogen,Ab exists widely in the external environment and the surface of human skin and mucosa.In the past,Ab often caused hospital acquired pneumonia.However,in recent years,due to the progress of medical technology,various kinds of medical operations have led to the increase of Ab infection and colonization in other systems of the human body.In addition,the widespread use of antimicrobial agents,the drug resistance of Ab is becoming more and more severe,which seriously threatens the life safety of patients in hospital,especially in ICU ward,and brings challenges to medical staff.Monitoring the susceptibility of Ab to commonly used drugs is valuable for guiding the treatment of drugs.It is very important for making preventive measures and cutting off the transmission routes of drug-resistant bacteria to investigate the epidemic characteristics of Ab,and to study the growth ability in different genotypes ofXDRAB.ObjectiveTo investigate the antimicrobial resistance of Acinetobacter baumannii isolated from ICU patients in 2016 for different commonly used antibiotics,and to study the epidemic characteristics of XDR in our hospital,finding out the main epidemic clones and measure their growth ability.MethodsThe agar dilution method was used to determine the minimum inhibitory concentration(MIC)of clinical isolates.The determination of the drug susceptibility test results was determined by CLSI2016.Chessboard method was used to carry out combined drug susceptibility test for Ab and calculate partial inhibitory concentration index(FICI).ST typing and eBURST analysis of XDR epidemic strains were carried out by MLST.According to the MLST results,the growth curve of bacteria was drawn by MTT method,and the in vitro growth ability of the main popular clone was compared with that of the standard strain ATCC19606.Results126 strains of Ab isolated from the ICU ward of our hospital in 2016 were sensitive to polymyxin and tigocycline,with high drug resistance to cephalosporins,cephalosporins and carbapenems,and low resistance to minocycline.The combination of polymyxin and linezolid could reduce the minimal inhibitory concentration of drugs on XDRAB.The results of MLST typing showed that ST 195 was the main clones in the ICU ward of our hospital,followed by ST208 and ST369,and a few other ST types belonging to CC92 clones were isolated.The growth curves were plotted with the change of culture time of 3 main popular ST types and standard strains.Through repeated measurements of variance analysis,there was significant difference between the differentdifference time periods of the bacteria(P<0.001),and there was a significant between ST195 and ST369(P<0.001),but there was no significant difference between ST208 and ATCC19606(P<0.001).P=0.691).ConclusionIn the ICU ward of our hospital,Acinetobacter Bauman had high resistance to most of the commonly used antibiotics.The resistance rate to minocycline was not high so it could be considered as an empirical drug.tigocycline or polymyxin can be selected,which was effective for XDR caused infectious diseases.Meanwhile,there was outbreak of XDRAB in ICU ward.The main epidemic STs were consistent with STs in some parts of China.The growth ability of ST 195 and ST369 was stronger than that of standard strain ATCC19606.It may be one of the factors which are prevalent in the ward,and the mechanism of this phenomenon needs to be further studied. |
PDF Full Text Request