产超广谱β-内酰胺酶肺炎克雷伯菌CTX-M基因型和耐药性分析

Objective To investigate the distribution and subtypes of bla(subscript CTX-M) and antimicrobial resistance of extended-spectrum β-lactamase-producing Klebsiella pneumoniae. Methods Subgroups of CTX-M1, 2, 8 and 9 were detected by specific PCR in 74 non-replicated isolates of K. pneumoniae collected from four hospitals in Harbin. Antimicrobial susceptibilities to the clinical relevant broad-spectrum β-lactams and β-lactam/inhibitor combinations were assayed by disk diffusion method. Resistance against cefotaxime, ceftazidime and ceftriaxome in isolates carrying bla(subscript CTX-M) was compared with that in those without the gene. Results bla(subscript CTX-M1) and bla(subscript CTX-M9) were found in 25.7% and 39.2% of the ESBL-producing K. pneumoniae, respectively. Subtypes of bla(subscript CTX-M2) and bla(subscript CTX-M8) were not detected. No statistical differences were found about the resistance rates to cefotaxime, ceftazidime and ceftriaxome between strains with bla(subscript CTX-M) and those without the gene detected. Conclusion It is revealed that bla(subscript CTX-M1) and bla(subscript CTX-M9) were most prevalent among the ESBL-producing K. pneumoniae in Harbin. Isolates carrying genes belong to both subtypes were also found. Resistance patterns to cefotaxime, ceftazidime and ceftriaxome were not decided prominently by CTX-M-type ESBLs in this area.