| Objective: The polymerase chain reaction(PCR)method was used to detect the carrying status of the β-lactamase-resistant gene of imipenem resistant Acintebacter baumannii in the hospital.The prevalence and homology of drug-resistant Acinetobacter baumannii strains were also analyzed.Methods:1.A total of 50 CRAB strains were separated by using Vitek 2 Compact from August 2017 in December 2019,and PCR amplified for inherent gene OXA-51 was applied to identify Streptocytes.2.Amplify β-lactamase genes(OXA-23,OXA-24,OXA-51,OXA-58,OXA-143,PER,SHV,IMP,VIM,TEM,ADC)and insertion sequence(ISAbla-oxa-23,ISAbla-oxa-58)were detected by PCR and agarose gel electrophoresis.3.The homology of 50 clinically isolated CRABs was analzed by PFGE technology.Results:1.The 50 strains of CRAB bacillus was mainly isolated from sputum(72%),bronchoscopy alveolar lavage fluid(18%),blood(4%),urine(2%)anddrainage(2%).and most specimen were from Neurology Intensive Care Unit(NICU)(28%),Emergency Intensive Care Unit(EICU)(22%),and Intensive Care Unit 3(ICU3)(20%).2.Among the 50 CRAB strains,9 strains(18%)were confirmed to resistant to 11 antibiotics,which present 100% resistance rate to imipenem,ceftazidime,ceftriaxone,ampicillin/sulbactam,and ciprofloxacin,and 90% to the remaining,including cefepime,piperacillin/tazobactam,gentamicin,tobramycin,and resistance rate to levofloxacin was 44%.3.All 50 CRABs resistance gene were confirmed to contain OXA-51,ADC,ISAbal-OXA-23,90% of strains contain resistance gene OXA-23,and 46% of VIM,10% of SHV were also dectected.However,the resistance genes that OXA-24,OXA-58,OXA-143,IMP,PER,TEM,ISAbal-OXA-58 were not found.4.The homology analysis of 50 CRAB strains by pulsed gel electrophoresis technique(PFGE)showed that all strains could be assorted to five different clusters(A ~E)including 17 strains(34%)in clone A containing A1 and A2 subtypes,a total of,4strains(8%)in B clone,22 strains(44%)in C clone containing C1 and C2 subtypes,a total of 6 strains(12%)in D clone including D1,D2 subtypes,and 1 strain(2%)in group E.Specifically,specimen of group A1 were mainly from EICU,NICU,ICU3,group A2 and D2 were mainfrom ICU3,group B were mainfrom ICU1,group C1 and C2 were main from NICU,and group C2 were distributed in all departments except for 120 wards.Whereas,groups D1 and E were only from EICU and ward 120,respectively.Of all groups of CRAB,the type C2 have the most popular distribution in departments of the hospital,accounting for 30% of all clones.5.From August 2017 to December 2019,15 CRAB strains assorted to C2 clones were isolated from 6 wards of this hospital(neurology ICU,emergency ICU,ICU3 room,ICU1 room,neurosurgery and respiratory Internal medicine ward)with time spanning of 16 months.The genotype of the C2 subtype strain is consistent to drug-resistant phenotype.Among them,three C2 isolates were obtained within 1 week in the intraneural NICU ward,which were from adjacent beds or separated only by 1bed unit,indicating that C2 type clone strains have been popular among many departments in the hospital.Conlusion:1.Most of the 50 CRAB strains were isolated from sputum,and from the department of NICU,emergency ICU and ICU3.2.The CRAB stains carries the resistance genes that OXA-51,OXA-23,ADC and ISAbal-OXA-23 with high genotypes,which is the main cause of Carbapenems andβ-lactam resistance.4.Homology analysis of 50 CRAB strains by PFGE revealed that the strains were divided into 5 clusters,the C2 type is the most popular type.5.Between August 2017 and December 2019,an outbreak of CRAB C2 stubtype occurred in 6 wards of this hospital. |
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