金黄杆菌属β内酰胺酶基因型研究

Investigation of β-lactamase genotypes of Chryseobacterium/Flavobacterium spp.

目的了解金黄杆菌属β内酰胺酶基因型的分布。方法采用琼脂稀释法检测43株脑膜炎败血金黄杆菌、16株产吲哚金黄杆菌和10株黏金黄杆菌对15种抗生素的最低抑菌浓度;用三维试验和改良三维试验检测碳青霉烯酶;用2-巯基丙酸协同试验检测金属酶;用6对针对金黄杆菌属的特异性引物扩增金黄杆菌的β内酰胺酶基因并测序。结果喹诺酮类抗生素的 MIC_(50)和 MIC_(90)较低,其余的抗生素的 MIC 值均很高,黏金黄杆菌的 MIC 值要低于其他两种金黄杆菌。表型筛选试验脑膜炎败血金黄杆菌中共检测到26株产金属酶,阳性率为60.5%,43株全部产超广谱β内酰胺酶,阳性率为100%;产吲哚金黄杆菌和黏金黄杆菌均未检出超广谱β内酰胺酶,产吲哚金黄杆菌检出11株金属酶,阳性率为68.8%;黏金黄杆菌检出6株金属酶,阳性率为60%。脑膜炎败血金黄杆菌检出金属酶基因型 Bla-B1、B2、B3、B5、B11共5种,Bla-GOB2、GOB4、GOB6、GOB8共4种;检出超广谱β内酰胺酶 CME-1型1种。产吲哚金黄杆菌3株均为 IND-1型金属酶基因型。黏金黄杆菌检出6株 CGB 金属酶基因型。同时发现产吲哚金黄杆菌有8株,黏金黄杆菌有3株没有检测到目前国内外所报道的基因型。结论金黄杆菌属基因型的研究为临床抗生素的合理应用,降低医院感染以及新型抗生素的开发提供重要的指导意义。

Objective To understand the distribution of the genotypes of β-lactamases in Chryseobacterium/Flavobacterium spp. Methods Minimum inhibitory concentrations （MICs） of 43 Chryseobaclerium 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-β-lactamases （MBL）. Genes of β-1actamases were amplified with 6 pairs of primers special for Chryseobacterium/Flavobacterium spp. and the amplified genes were sequenced. Results MIC50 and MIC50 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 β-lactamases （ESBLs） ; 12 C. indolagenes strains （68. 8% ） produced MBL; 6 （60%） C. gleum strains had MBL Genotypes of MBL in C. meningesepticum 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 β-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 β-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.