Novel carbapenem-hydrolyzing β-lactamase, KPC-1, from a carbapenem-resistant strain of Klebsiella pneumoniae
Novel carbapenem-hydrolyzing β-lactamase, KPC-1, from a carbapenem-resistant strain of Klebsiella pneumoniae
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DOI：
10.1128/aac.45.4.1151-1161.2001
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发表时间：
2001-04-01
影响因子：
4.9
通讯作者：
Tenover, FC
中科院分区：
文献类型：
--
作者：
Yigit, H;Queenan, AM;Tenover, FC
对显示出中度至高水平亚胺培南和美罗培南耐药性的肺炎克雷伯菌分离株进行了研究。两种药物的 MIC 均为 16 μg/ml。在克拉维酸存在下，针对亚胺培南和美罗培南的β-内酰胺酶活性受到抑制。该菌株还对广谱头孢菌素和氨曲南具有耐药性，等电聚焦研究证明了三种 β-内酰胺酶，pIs 分别为 7.2 (SHV-29)、6.7 (KPC-L) 和 5.4 (TEM-1)。通过特异性 PCR 和 DNA 序列分析证实了 bla(SHV) 和 bla(TEM) 基因的存在。大肠杆菌的转化和接合研究表明，pI 为 6,7 的 β-内酰胺酶 KPC-1（X，肺炎碳青霉烯酶-1）在大约 50 kb 的非接合质粒上编码。基因 bla(KPC-1) 被克隆到大肠杆菌中，并显示出对亚胺培南、美罗培南、广谱抗性。新型碳青霉烯类水解 β-内酰胺酶 KPC -1 的氨基酸序列与来自粘质沙雷菌 S6 的 pI 9.7 碳青霉烯类水解 β-内酰胺酶 Sme-1 的氨基酸序列有 45% 的同一性，水解研究表明纯化的 KPC-1 不仅可以水解碳青霉烯类，还可以水解青霉素，头孢菌素类和单菌素类。 KPC-1 对美罗培南具有最高的亲和力。动力学研究还表明，克拉维酸和他唑巴坦抑制 KPC-1。对肺炎克雷伯菌亲本菌株外膜蛋白的检查表明，尽管存在 OmpK36，但该菌株不表达可检测水平的 OmpK35 和 OmpK37。我们得出的结论是，肺炎克雷伯菌菌株 1534 的碳青霉烯耐药性主要是由于产生了新的 Bush 组 2f、A 类碳青霉烯水解 β-内酰胺酶 KPC -1，尽管孔蛋白表达的改变也可能发挥作用。
A Klebsiella pneumoniae isolate showing moderate to high-level imipenem and meropenem resistance was investigated. The MICs of both drugs were 16 mug/ml. The beta -lactamase activity against imipenem and meropenem was inhibited in the presence of clavulanic acid. The strain was also resistant to extended-spectrum cephalosporins and aztreonam, Isoelectric focusing studies demonstrated three beta -lactamases, with pIs of 7.2 (SHV-29), 6.7 (KPC-L), and 5.4 (TEM-1). The presence of bla(SHV) and bla(TEM) genes was confirmed by specific PCRs and DNA sequence analysis. Transformation and conjugation studies with Escherichia coli showed that the beta -lactamase with a pI of 6,7, KPC-1 (X, pneumoniae carbapenemase-l), was encoded on an approximately 50-kb nonconjugative plasmid, The gene, bla(KPC-1), was cloned in E. coli and shown to confer resistance to imipenem, meropenem, extended-spectrum cephalosporins, and aztreonam, The amino acid sequence of the novel carbapenem-hydrolyzing beta -lactamase, KPC -1, showed 45% identity to the pI 9.7 carbapenem-hydrolyzing beta -lactamase, Sme-l, from Serratia marcescens S6, Hydrolysis studies showed that purified KPC-1 hydrolyzed not only carbapenems but also penicillins, cephalosporins, and monobactams. KPC-1 had the highest affinity for meropenem, The kinetic studies also revealed that clavulanic acid and tazobactam inhibited KPC-1, An examination of the outer membrane proteins of the parent K, pneumoniae strain demonstrated that the strain does not express detectable levels of OmpK35 and OmpK37, although OmpK36 is present. We concluded that carbapenem resistance in K, pneumoniae strain 1534 is mainly due to production of a novel Bush group 2f, class A, carbapenem- hydrolyzing beta -lactamase, KPC -1, although alterations in porin expression may also play a role.