| ObjectiveTo analyze the epidemic trend and risk factors of the infection of carbapenem-resistant Acinetobacter baumannii in hospital,and provide basis for controlling hospital infection.Methods(1)A total of 94 strains of Acinetobacter nosocomial were collected in hospital during 2014 to 2016.Data for each isolate and each patient were obtained through review of microbiology lab results and medical records.(2)Drug susceptibility test for 94 strains of Acinetobacter baumannii were determined by the VITEK 2 compact system.(3)Detect the number of Acinetobacter baumannii.The drug resistant genes were detected through Multiplex PCR assay.The presence of blaOXA-23-like,blaOxA-24-like,blaOXA-51-like,and blaOXA-58-like genes were detected through Multiplex PCR assay.Metallo-b-lactamase encoding genes,blaNDM-like,blaIMP-like and blaVIP-like,were detected with PCR conditions and primers as previously described.The blaOXA-24-like variant was further identified through PCR and DNA sequencing as described.(4)REP-PCR was used for genotyping of all the Acinetobacter baumannii isolates.Chose some isolates from each different REP-PCR types were randomly chosen for multilocus sequence typing(MLST)analysis according to 'Pasteur' scheme.(5)Refer the literatures of Acinetobacter baumannii,based on the results of MLST,the ST and geographical location of blaOXA-24-like gene were analyzed by using eBURST software.(6)According to the results of the drug sensitivity test,these 94 patients were divided into the carbapenem-resistant group and non-carbapenem-resistant group.The risk factors of the infection of carbapenem-resistant Acinetobacter baumannii were by Logistic regression analysis.Results(1)Basic information analysis the research object,according to the results of 94 patients with predominantly male(71.3%),52.1%of 94 patients were 75?89 years old,mainly from ICU(46.8%),94 patients of acinetobacter infection is most isolated from sputum specimens(80.9%).(2)Among the 94 A.baumannii isolates,70 isolates(74.5%)were resistant to carbapenems(meropenem or imipenem).The rates of resistance to imipenem and meropenem was 66.0%and 74.5%.The rates of resistance to levofloxacin,ciprofloxacin,amikacin,gentamicin,ceftazidime,ampicillin/sulbactam,and piperacilin/tazobactam in A.baumannii were all above 50%.The rates of resistance to cefepime,minocycline and polymyxin was 30.4%,0 and 3.2%.(3)Of the 94 Acinetobacter isolates,89 isolates and 5 isolates were identified as A.baumannii and A.pittii,respectively.The detection of carbapenemase genes showed that 31(34.8%)of the 89 A.baumannii were positive for the blaOXA-23-like gene,while the leaving 39 isolates(43.8%)were positive for the blaOXA-24-like gene.All these isolates harboured blaOXA-51-like gene.The blaOXA-58-like gene was detected in only one A.baumannii isolate.DNA sequencing showed that all the blaOXA-24-like amplicons belonged to blaOXA-72.None of these Acinetobacter isolates were positive for blaIMP-like,blaVIM-like or blaNDM-1 genes.(4)The results of REP-PCR shown that these strains were clustered into 10 major types(type A-J)according to the cutoff value of 80%similarity.MLST analysis showed that all the isolates belong to ST2.(5)The main ST of blaOXA-24-like gene in A.baumannii was ST 2,this the ST type mainly from Croatia,France,Sweden,Poland,Algeria,Libya,Germany,Israel,Spain and China,the most of Europe countries,followed by Asia and Africa.The blaOXA-24-like gene found in this study belongs to the ST 2 type,which is the main popular type in the world.(6)The results of univariate logistic analysis showed that stay in ICU,mechanical ventilation,center venipuncture,nasogastric intubation,Carbapenems antibiotics,Penicillin antibiotics and the number of antibiotics were the risk factors of carbapenem-resistant Acinetobacter baumannii.In multivarite analysis,it was associated with nasogastric intubation(OR=10.321,CI:1.690?63.034,P=0.011),Carbapenems antibiotics(OR=21.613,CI:2.249?207.674,P=0.008)and Penicillin antibiotics(OR=15.267,CI:2.481?93.944,P=0.003).ConclusionsThe rate of resistance rate of antibiotics in Acinetobacter baumannii was higher in this hospital,and the risk factors of carbapenem-resistant Acinetobacter baumannii in the hospital were nasogastric intubation,carbapenenes antibiotics and penicillin antibiotics.The rate of blaOXA-24-like gene and blaOXA-23-like gene in the Acinetobacter baumannii was higher,and it was the same clone,and the Acinetobacter baumannii was cloned in the hospital.Enhanced infection control measures are needed to reduce the ongoing dissemination of this high risk clone. |
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