广州地区肺炎克雷伯菌产TEM型及SHV型β-内酰胺酶基因表型的研究

目的对广州地区产β-内酰胺酶肺炎克雷伯菌TEM型和SHV型基因型及其分子流行病学进行研究。方法对57株产β-内酰胺酶肺炎克雷伯菌进行blaTEM和blaSHV基因扩增,分别采用变性高效液相色谱技术和测序法对扩增产物进行分析,以明确基因类型。结果57株肺炎克雷伯菌均扩增出blaTEM和blaSHV基因。测序结果表明,TEM-116 ESBL32株,占54．2％;SHV型以SHV-12为主,占33．3％,其次为SHV-11和SHV-2a等,还发现5种新的SHV基因亚型。54株菌株同产TEM和SHV型β-内酰胺酶,占94．7％;其中13．0％同产TEM-116和SHV-12ESBL。结论TEM-116和SHV-12分别是广州地区产β-内酰胺酶肺炎克雷伯菌TEM型及SHV型耐药质粒主要的基因亚型,blawTEM和blaSHV在肺炎克雷伯菌中同产的比例很高,这提示本地区即将或已经面临肺炎克雷伯菌新耐药机制的抵抗和流行,必须加强对产ESBL肺炎克雷伯菌的分子流行病学监测。

Genotype of TEM- and SHV-type beta-lactamase producing Klebsiella pneumoniae in Guangzhou area

Objective To determine the prevalence and genotypes of TEM- and SHV-type beta-lactamase-producing Klebsiella pneumoniae in Guangzhou area. Methods Genotype determination of TEM- and SHV-type beta-lactamases were performed by PCR amplification followed by denaturing high-performance liquid chromatography (DHPLC) and DNA sequencing among 57 straine of klebsiella pneumonial obtained from the hospitals in Guangzhou. Results The genes bla_ TEM and bla_ SHV were amplified from all strains. TEM-116 type ESBLs were found in 56.14% (32/57) of the isolates. SHV-12 (n=19), -11(n=11), -2a (n=6),-28 (n=4), -26 (n=1), -33(n=1) and five novel SHV-type beta-lactamases were identified among the SHV-type beta-lactamases. These novel enzymes were designated from SHV-64, -65, -66, -67 and SHV-69, which derived from SHV-1 beta-lactamase or SHV-12 ESBL. A total of 94.74% of the isolates (54/57) produced both TEM- and SHV-type beta-lactamases simultaneously, in which 13.0% were TEM-116 and SHV-12 (n=12). Conclusion TEM-116 and SHV-12 are the predominant TEM- and SHV-type genotypes of Klebsiella pneumoniae producing beta-lactamases in Guangzhou. This area is confronted with the prevalence of the phenotypes of Klebsiella pneumoniae that simultaneously produce TEM- and SHV-type beta-lactamases.