Analysis Of Distribution And Drug Resistance Of Pathogenic Bacteria In Liver Transplant Recipients In A Third Class Hospital

Objective: To investigate the distribution,drug resistance and potential donor-derived infection of pathogenic bacteria in liver transplant recipients in a third class hospital,so as to provide scientific basis for the rational use of antibiotics,reduce the occurrence of drugresistant strains and control the prevalence of hospital infection.Methods: The distribution of pathogenic bacteria isolated from various specimens submitted by 904 liver transplant recipients in a third-class grade A hospital from March2014 to December 2021 in Qingdao and their drug sensitivity test results were analyzed retrospectively.The main drug-resistant bacteria in liver transplant recipients from January2022 to September 2022 were collected.The WHONET5.6 software was used to carry out statistical analysis for the list of strains and the rate of bacterial resistance,and all the original data were classified,summarized and charted by Excel.The strains were identified by the VITEK MS automatic rapid microbial mass spectrometry detection system and the VITEK 2 COMPACT system of the French Bio Mèrieux company,and the drug sensitivity test was performed by the VITEK 2 COMPACT system,the disk diffusion method and the broth microdilution method.The mechanism of drug resistance was analyzed by carbapenem enzyme inhibitor enhancement test,enzyme immuno-chromatography and the next-generation sequencing technology.Results: 1.A total of 2208 strains of pathogenic bacteria meeting the inclusion criteria were collected between 2014 and 2021,mainly from respiratory tract(31.25%),bile(22.28%),ascites(13.18%)and blood samples(8.38%).2.The infected rates of Gram-negative bacteria,Gram-positive bacteria,and fungi were 57.97%,38.50% and 3.53%,respectively,in liver transplant recipients.Gram-negative bacteria were mainly Klebsiella pneumoniae subspecies pneumoniae(10.69%),Escherichia coli(8.24%),Pseudomonas aeruginosa(8.24%),Acinetobacter baumannii(7.93%),Stenotrophomonas maltophilia(6.61%),and Gram-positive bacteria were mainly Enterococcus faecium(10.42%)and Staphylococcus epidermidis(8.06%),fungi were mainly Candida glabra(1.00%)and Candida glabra(0.77%).3.The detection rate of Klebsiella pneumoniae subspecies pneumoniae,the main Enterobacterales bacterium of infected liver transplant recipients from 2017 to 2020,showed an increasing trend year by year,accounting for more than Escherichia coli.Among the main non-fermentative bacteria,the detection rate of Pseudomonas aeruginosa increased year by year from 2016 to 2019,and decreased in 2020 and 2021.The detection rate of Acinetobacter baumannii showed a rapid growth trend from 2016 to 2018,and decreased rapidly from 2019 to 2021.The detection rate of Stenotrophomonas maltophilia is increasing year by year.4.The distribution of pathogenic bacteria from different specimens of liver transplant recipients is different.Pseudomonas aeruginosa,Stenotrophomonas maltophilia,Klebsiella pneumoniae subspecies pneumoniae and Acinetobacter baumannii were the main pathogenic bacteria isolated from respiratory tract specimens.Enterococcus faecium was the main pathogenic bacteria isolated from bile and ascites specimens.Escherichia coli,Staphylococcus epidermidis and Klebsiella pneumoniae pneumonia subspecies were the main pathogenic bacteria isolated from blood specimens.5.Drug sensitivity data showed that Enterobacterales bacteria had a high resistance rate to cephalosporins and fluoroquinolones,with no strains resistant to tegacyclin.Compared with Escherichia coli,Klebsiella pneumoniae subspecies pneumoniae had a higher resistance rate to meropenem(14.71% vs 5.66%)and imipenem(11.35% vs 6.29%).Non-fermentative bacteria had a relatively high resistance rate to carbapenems.Among gram-positive cocci,Enterococcus faecium had a resistance rates of6.17% to vancomycin and 2.44% to quinupristin/dalfopristin,with no strains resistant to tigecycline and linezolid.The drug resistance rates of Staphylococcus epidermidis to rifampin,linezolid and quinupristin/dalfopristin were 6.51%,3.92% and 1.18%,respectively.And there was no strains resistant to tigecycline and vancomycin.6.Among2208 strains of pathogenic bacteria,287 strains of drug-resistant bacteria were mainly monitored,accounting for 13%.There were 128 carbapenem-resistant Acinetobacter baumannii(44.60%),88 carbapenem-resistant Pseudomonas aeruginosa(30.66%),26carbapenem-resistant Klebsiella pneumoniae subspecies pneumoniae(9.06%),23methicillin-resistant Staphylococcus aureus(8.01%),11 carbapenem-resistant Escherichia coli(3.83%),and 11 vancomycin-resistant enterococci(3.83%).The detection rate of CRKPN was the highest in 2019(35.29%)and remained at about 11% in the past two years.The detection rate of CRAB remained at a high level(58.33% ~ 98.39%)from 2015 to2019,but the detection rate of CRAB decreased significantly in 2020 and increased again in 2021.Since 2017,the detection rate of CRPA remained at a high level of about 50%.The detection rate of MRSA remained at about 30% in the past three years.The detection rates of CRECO and VRE were low.7.Twenty-four carbapenem-resistant bacteria were collected,including 10 CRAB(41.67%),6 CRKPN(25.00%),4 CRPA and 4 CRECO(16.67%).The resistance genes carried by CRAB and CAPA were mainly bla OXA gene,enterobacterium producing metallo-β-lactamase mainly carried bla NDM-5 gene,and Klebsiella pneumoniae producing serine carbapenemase mainly carried bla KPC-2 gene.In addition to carbapenemase gene,these 24 drug-resistant bacteria also carried a variety of resistance genes.8.The results of multi-locus sequence typing showed that the MLST typing of S1 and S2 strains from donor specimens and S3 strains from recipient specimens were ST806,MLST typing of S4 and S5 strains from donor specimens and S6 strains from recipient specimens were ST540.And strains S8 and S9,S19 and S20,S22 and S23 from different recipients had the same MLST typing,which were ST938,ST20,and ST2237,respectively.Conclusions: 1.In this study,Gram-negative bacteria are the main pathogens of liver transplant recipients,and the main pathogens in different infection sites are different.2.In this study,CRAB and CAPA mainly carry bla OXA gene,enterobacterium producing metallo-β-lactamase mainly carries bla NDM-5 gene,and Klebsiella pneumoniae producing serine carbapenemase mainly carries bla KPC-2 gene.3.In this study,CRAB infection in liver transplant recipients is donor-derived infection,and there may be clones of Acinetobacter baumannii carrying bla OXA-66 and bla OXA-23 genes and Klebsiella pneumoniae carrying bla NDM-5 and bla KPC-2 genes among liver transplant recipients.