Distribution and drug resistance of Acinetobacter baumannii in ICU of seven medical institutions in Shanghai
OBJECTIVE To study the distribution of Acinetobacter baumannii in the environment of intensive care unit(ICU)of medical institutions,and to analyze the correlation between drug resistant phenotypes and drug re-sistant genes,so as to provide data support for formulating infection control strategies.METHODS ICU environ-mental samples from 7 medical institutions were collected by cotton swab smear method from Jan 2019 to Dec 2019.The strains were identified by matter-assisted laser desorption ionization time-of-flight mass spectrometer.The drug susceptibility was tested by microbroth dilution method.Drug-resistant genes were obtained by whole genome sequencing.RESULTS A.baumannii widely existed on the enviromental surfaces of medical institutions.The total detection rate was 6.79％(114/1 680),with the highest proportion of 12.28％(14/114)on surfaces of the mattress directly touched by patients.The drug resistance rates of ceftazidime and ciprofloxacin were the high-est,both of which were 84.21％(96/114).The multi-drug resistance rate of 114 strains was 85.96％(98/114).The drug resistance rates to tigecycline and polymyxin B were 1.75％(2/114)and 0.88％(1/114),respectively.Whole genome sequencing results showed that 114 strains of A.baumannii carried 6 classes of 26 kinds of drug-resistant genes,and the highest carrying rate of β-lactam resistance genes was 99.12％(113/114),no quinolone resistance gene was carried.Multivariate logistic regression analysis showed that the resistant genes of bla OXA.23,blaOXA-66,aph(3")-Ib,aph(6)-Id,arm A,sul1,sul2 and blaTEM-1D were all positively correlated with their re-spective antibiotic resistance(P＜0.05).Tet(B)resistance gene had no significant correlation with tigecycline.CONCLUSION A.baumannenii is common in ICU environment of medical institutions,and the drug resistance sit-uation is severe.blaOXA-23,blaOXA-66,aph(3")-Ib,aph(6)-Id,armA,sul1,sul2 and blaTEM-1D are the main drug re-sistance genes.Tetracycline and quinolone antibiotic resistance phenotypes and genotypes are inconsistent,and the resistance mechanism is complex.
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