Study On Antibiotic Resistance And Carbapenem Resistance Encoded By CfiA Gene Of Bacteroides From The Intestinal Tract Of Children

Objective : The objective is to explore the antibiotic resistance of Bacteroides from the intestinal tract of children isolates in Hohhot.Furthermore,the correlation between the cfiA gene as well as the insertion sequence(IS),and the carbapenem resistance of Bacteroides isolates,is studied.Methods: The fecal samples and clinical data of hospitalized children in the pediatric department of the hospital are collected between March 2021 and September 2022.The samples are tested for purity and oxygen tolerance.Both Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry and VITEK-2 Compact automated microbiology system with anaerobes and corynebacterium(ANC)cards are used to identify and isolate the Bacteroides.Susceptibility of multiple antibiotics against Bacteroides and the minimum inhibitory concentration of imipenem are determined using the agar dilution method and the broth microdilution method.For Bacteroides with reduced carbapenem sensitivity,the production of metallo-beta-lactamase is measured by EDTA inhibition assay.The whole DNA of Bacteroides is extracted.The cfiA gene and its insertion sequence(IS)are amplified by polymerase chain reaction,and analyzed by imaging system after electrophoresis.SPSS 21.0 software is used for statistical analysis.The Chi-square test and Fisher’s exact test are used for comparison between groups for the enumeration data.Results: 1.In this study,219 Bacteroides isolates are collected from 711 fecal samples,with a detection rate of 30.80%,and Bacteroides fragilis are most common among these Bacteroides.2.The resistance rate of Bacteroides to imipenem is 12.3%(27/219).The 219 Bacteroides are highly resistant to penicillin(100%),amoxicillin(97.7%),clindamycin(97.3%),ticacillin(70.3%)and piperacillin(68.1%),moderate resistance to cefotetan(48.4%),cefoxitin(36.1%),amoxicillin-clavulanicacid(17.6%),imipenem(12.3%),and mild resistance to metronidazole(9.1%),ticarcillin-clavulnic acid(5.5%),piperacillin-tazobactam(4.4%)and chloramphenicol(1.1%).3.The resistance rate of Bacteroides to imipenem in this study is significantly higher than that in the United States(0.8%),9 European countries(0.6%),Poland(0%),Spain(1.8%),Argentina(1.5%),Slovenia(1.3%),Canada(0.9%),Italy(1.35%),and India(0%),and lower than that of other regions(25.1%)in China(P<0.05).It is slightly lower than that in adult departments of this hospital(13.73%),and the difference is not statistically significant(P >0.05).4.A total of 36 Bacteroides carrying cfiA gene are isolated in this study,accounting for 16.4%,among which 27 isolates are resistant to imipenem,8 are sensitive,and 1 is intermediate.5.The carrying rate of cfiA gene in this study is significantly higher than that in the United States(1.27%),9 European countries(7.45%),Poland(1.8%),Spain(0.72%),Argentina(4.04%)and Slovenia(8.2%),lower than China(2009-2019)(36.4%),(2017-2019)(38.9%),Turkey(27%),India(52%),etc.(P<0.05).It was slightly lower than that in adult departments of this hospital(22.2%),and the difference was not statistically significant(P > 0.05).6.In cfiA gene positive isolates,the detection rate of insertion sequence(IS)is 69.4%(25/36).7.32 Bacteroides with decreased sensitivity or resistance to imipenem show positive EDTA inhibition assay.Conclusions: 1.Bacteroides fragile is most common among the Bacteroides in children’s intestinal tract in Hohhot.2.The resistance rate of Bacteroides to imipenem is 12.3% in Hohhot,and the resistance rate to penicillin,ticacillin and piperacillin are 100%,70.3% and 68.1%,respectively.The resistance rates of cefotetan and amoxicillin clavulanic acid are 48.4% and 17.6%,respectively.The resistance rates of metronidazole,ticacillin clavulanic acid,piperacillin tazobactam and chloramphenicol are 9.1%,5.5%,4.4% and 1.1%,respectively.3.The resistance rate of Bacteroides to imipenem in Hohhot is significantly higher than that reported in some foreign studies,lower than the study in other area of China,and slightly lower than that reported in adult departments of this hospital.4.The cfiA gene carrying rate of children in Hohhot is 16.4%,and the insertion sequence(IS)detection rate of cfiA gene positive isolates is 69.4%.All 27 imipenem resistant isolates carry cfiA gene.5.The cfiA gene carrying rate in Hohhot is significantly higher than some foreign studies,and slightly lower than related studies in adult departments of this hospital.6.The increased resistance of Bacteroides to carbapenems from the intestinal tract of children in Hohhot is correlated with cfiA gene and its insertion sequence(IS).