Genetic Supports of blaOXA-23 in Acinetobacter baumannii and Their Clinical Significance / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To study the genetic supports of OXA-23 in Acinetobacter baumannii isolates and investigate the relationship between imipenem resistance acquiring and use of antibiotics.METHODS Consecutive selection of the 24 highly susceptive A.baumannii clinical isolates by imipenem was carried out.Genes of carbapenemases were detected by PCR and the colonial relationship of these isolates was evaluated by ERIC-PCR.Plasmids conjugation experiments and blaOXA-23 hybridization were performed to explore the gene location of blaOXA-23.RESULTS From all 24 susceptible A.baumannii isolates 10 were selected,including 6 multi-colonial blaOXA23 harboring strains.Plasmid conjugation experiments and Southern blotting experiments demonstrated that blaOXA-23 was not associated with integrons.CONCLUSIONS BlaOXA-23 may exist in a certain subset of apparently carbapenem sensitive Acinetobacter strains.When under consecutive selective pressure,bacteria harboring blaOXA-23 become the predominant group and subsequently the antibiotics resistance properties appear.It highlights the reasonable use of this category of antibiotics.