OBJECTIVE To investigate the distribution characteristics and drug resistance of multidrug-resistant Acinetobacter baumannii(MDRAB)detected clinically in the Army 73rd Group Military Hospital in Xiamen,and to study the carrying conditions of drug-resistant gene-related insertion sequence elements(IS)and transposons(Tn)in the isolated strains of MDRAB.METHODS A total of 300 strains of Acinetobacter baumannii detected from inpatients admitted to the Army 73rd Group Military Hospital from Jan.2016 to Feb.2024 were collected.Automatic bacterial identification instruments and drug susceptibility tests were used for bacterial identi-fication and drug resistance analysis.Polymerase chain reaction(PCR)was employed to detect 6 Tn genetic mark-ers(merA,TnpU,TnpM,TnpR,TnpA21,TnpA7)and 3 IS genes(ISEcp1,ISCR1,IS26)in MDRAB strains.The detected IS and Tn-positive genes were subjected to sequencing and alignment verification.RESULTS Among 300 Acinetobacter baumannii strains,49(16.33％)were MDRAB.Most MDRAB strains were found in patients aged 75 and above(44.90％),mainly isolated from the brain center ICU(34.69％),critical care medi-cine ICU(20.41％),and respiratory medicine department(16.33％),sputum specimens accounted for the ma-jority(77.55％).MDRAB strains exhibited high drug resistance rates(≥97％)to cefpodoxime,nitrofurantoin,and aztreonam.MDRAB strains showed drug resistance rates＞80％to most antimicrobial agents,but were sensi-tive to polymyxin(12.24％)and tigecycline(28.57％).Compared with non-MDRAB strains,there were statisti-cally significant differences in drug resistance to common antimicrobial agents(P＜0.05).Among MDRAB strains,ISCR1,IS26,TnpU and TnpM genes were detected in IS and Tn,with detection rates of 51.02％,48.98％,51.02％and 22.45％,respectively.merA,TnpR,TnpA21,TnpA7 and ISEcp1 were not detected.CONCLUSIONS The drug resistance of Acinetobacter baumannii is severe,especially in elderly and criti-cally ill patients.The transmission of MDRAB strains may be associated with the genes ISCR1,IS26,TnpM and TnpU.

OBJECTIVE To investigate the distribution characteristics and drug resistance of multidrug-resistant Acinetobacter baumannii(MDRAB)detected clinically in the Army 73rd Group Military Hospital in Xiamen,and to study the carrying conditions of drug-resistant gene-related insertion sequence elements(IS)and transposons(Tn)in the isolated strains of MDRAB.METHODS A total of 300 strains of Acinetobacter baumannii detected from inpatients admitted to the Army 73rd Group Military Hospital from Jan.2016 to Feb.2024 were collected.Automatic bacterial identification instruments and drug susceptibility tests were used for bacterial identi-fication and drug resistance analysis.Polymerase chain reaction(PCR)was employed to detect 6 Tn genetic mark-ers(merA,TnpU,TnpM,TnpR,TnpA21,TnpA7)and 3 IS genes(ISEcp1,ISCR1,IS26)in MDRAB strains.The detected IS and Tn-positive genes were subjected to sequencing and alignment verification.RESULTS Among 300 Acinetobacter baumannii strains,49(16.33％)were MDRAB.Most MDRAB strains were found in patients aged 75 and above(44.90％),mainly isolated from the brain center ICU(34.69％),critical care medi-cine ICU(20.41％),and respiratory medicine department(16.33％),sputum specimens accounted for the ma-jority(77.55％).MDRAB strains exhibited high drug resistance rates(≥97％)to cefpodoxime,nitrofurantoin,and aztreonam.MDRAB strains showed drug resistance rates＞80％to most antimicrobial agents,but were sensi-tive to polymyxin(12.24％)and tigecycline(28.57％).Compared with non-MDRAB strains,there were statisti-cally significant differences in drug resistance to common antimicrobial agents(P＜0.05).Among MDRAB strains,ISCR1,IS26,TnpU and TnpM genes were detected in IS and Tn,with detection rates of 51.02％,48.98％,51.02％and 22.45％,respectively.merA,TnpR,TnpA21,TnpA7 and ISEcp1 were not detected.CONCLUSIONS The drug resistance of Acinetobacter baumannii is severe,especially in elderly and criti-cally ill patients.The transmission of MDRAB strains may be associated with the genes ISCR1,IS26,TnpM and TnpU.