Abstract:Objective To investigate the drug resistance of clinically isolated Acinetobacter baumannii (AB) and distribution of biofilm-related genes and integrons, explore the relationship between extensively drug-resistant AB (XDR-AB) biofilm-related genes, integrons and drug resistance. Methods Minimum inhibitory concentration (MIC) of 17 kinds of antimicrobial agents against 59 AB strains isolated from clinical specimens of a hospital in Chengdu from 2019 to 2020 were performed by micro-broth method, 17 biofilm-related genes and class Ⅰ, Ⅱ and Ⅲ integrase genes were amplified by polymerase chain reaction (PCR), variable regions of class Ⅰ integrase positive strains were amplified and sequenced. Results Resistance rate of 59 AB strains to minocycline was 1.69%, to imipenem and meropenem were 67.80% and 71.19% respectively, and to other antimicrobial agents were 59.32%-84.75%. Among 59 AB strains, 40 strains (67.80%) were XDR-AB, 5 strains (8.47%) were multidrug-resis-tance AB (MDR-AB), and 14 strains (23.73%) were sensitive strains. Among 17 biofilm-related genes of 59 AB strains, detection rates of 6 biofilm-related genes bfmR, bfmS, csuC, csuD, csuE, and pgaD were 100%, detection rates of the other 11 biofilm-related genes were 74.58%-98.31%. Detection rates of 4 biofilm-related genes abaI, epsA, pglC, and ompA in XDR-AB were 100%, 95.00%, 87.50% and 100% respectively, which were higher than those in sensitive AB strains (64.29%, 7.14%, 42.86% and 50.00%, all P < 0.05). The detection rate of intI-1 integrase gene of AB and XDR-AB were 66.10% (39/59) and 90.00% (36/40) respectively, and sensitive AB strain was not found. Among 39 class Ⅰ integrase positive strains, 38 strains of class Ⅰ integron variable region were detected, including 35 XDR-AB strains and 3 MDR-AB strains. Conclusion Detection rate of XDR-AB among AB is high, it is speculated that the biofilm-related genes abaI, epsA, pglC, ompA and class Ⅰ integron carried by XDR-AB are closely related to drug resistance.