Investigation of ?-lactamase genotypes of Chryseobacterium/Flavobacterium spp / 中华检验医学杂志

ABSTRACT

Objective To understand the distribution of the genotypes of ?-lactamases in Chryseobacterium/Flavobacterium spp.Methods Minimum inhibitory concentrations (MICs) of 43 Chryseobacterium meningosepticum strains,22 Chryseobacterium indologenes strains and 10 Chryseobacterium gleum strains against 15 antibiotics were determined by agar dilution method.3-D test and modified 3-D test were used to identify carbapenamase.2-mercaptopropionic acid inhibitory test was used to confirm metallo-?-lactamases (MBL).Genes of ?-lactamases were amplified with 6 pairs of primers special for Chryseobacterium/Flavobacterium spp.and the amplified genes were sequenced.Results MIC_(50) and MIC_(90) of quinolones were lower comparing to other antibiotics.MICs of C.gleum against 15 antibiotics were lower than other Chryseobacterium/Flavobacterium spp.Among 43 C.meningosepticum strains,26 strains (60.5%) produce MBL,but all strains (100%) produced extended-spectrum ?-lactamases (ESBLs);12 C.indologenes strains (68.8%) produced MBL;6 (60%) C.gleum strains had MBL.Genotypes of MBL in C.meningosepticum strains were Bla-B 1,2,3,5 and 11,and Bla-GOB 2,4,6 and 8,respectively.Only one genotype,namely CME-1,was identified for ESBL in C.meningosepticum.The genotype of MBL in 3 C.indolgenes strains was IND-1,and the 6 C.gleum strains contained CGB genotype.Meanwhile,there were 8 C.indolgenes strains and 3 C.gleum strains were confirmed to produce ?-lactamase,but their genotypes were unable to be detected using the current primers,implying that there were possible novel genotypes.Conclusions Investigation of genotypes distribution of ?-lactamase in Chryseobacterium/ Flavobacterium spp.can provide theoretical evidences and rational in the selection of antibiotics,control of noscomical infection and development of novel antibiotics.