ABSTRACT
Boronic acid transition state inhibitors (BATSIs) are competitive, reversible β-lactamase inhibitors (BLIs). In this study, a series of BATSIs with selectively modified regions (R1, R2, and amide group) were strategically designed and tested against representative class A β-lactamases of
Klebsiella pneumoniae
, KPC-2 and SHV-1. Firstly, the R1 group of compounds 1a to 1c and 2a to 2e mimicked the side chain of cephalothin, whereas for compounds 3a to 3c, 4a, and 4b, the thiophene ring was replaced by a phenyl, typical of benzylpenicillin. Secondly, variations in the R2 groups which included substituted aryl side chains (compounds 1a, 1b, 1c, 3a, 3b, and 3c) and triazole groups (compounds 2a to 2e) were chosen to mimic the thiazolidine and dihydrothiazine ring of penicillins and cephalosporins, respectively. Thirdly, the amide backbone of the BATSI, which corresponds to the amide at C-6 or C-7 of β-lactams, was also changed to the following bioisosteric groups: urea (compound 3b), thiourea (compound 3c), and sulfonamide (compounds 4a and 4b). Among the compounds that inhibited KPC-2 and SHV-1 β-lactamases, nine possessed 50% inhibitory concentrations (IC
50
s) of ≤600 nM. The most active compounds contained the thiopheneacetyl group at R1 and for the chiral BATSIs, a carboxy- or hydroxy-substituted aryl group at R2. The most active sulfonamido derivative, compound 4b, lacked an R2 group. Compound 2b (S02030) was the most active, with acylation rates (
k
2
/
K
) of 1.2 ± 0.2 × 10
4
M
−1
s
−1
for KPC-2 and 4.7 ± 0.6 × 10
3
M
−1
s
−1
for SHV-1, and demonstrated antimicrobial activity against
Escherichia coli
DH10B carrying
bla
SHV
variants and
bla
KPC-2
or
bla
KPC-3
and against clinical strains of
Klebsiella pneumoniae
and
E. coli
producing different class A β-lactamase genes. At most, MICs decreased from 16 to 0.5 mg/liter.
摘要
硼酸过渡态抑制剂(BATSIs)是一种竞争性、可逆的β-内酰胺酶抑制剂(BLIs)。本研究战略性地设计了一系列具有选择性修饰区域(R1、R2 和酰胺基)的 BATSIs,并针对肺炎克雷伯氏菌的代表性 A 类 β-内酰胺酶进行了测试。
肺炎克雷伯菌
KPC-2 和 SHV-1。首先,化合物 1a 至 1c 和 2a 至 2e 的 R1 基团模仿了头孢菌素的侧链,而化合物 3a 至 3c、4a 和 4b 的噻吩环则被苯基取代,这是典型的苄青霉素。其次,R2 基团的变化包括取代的芳基侧链(化合物 1a、1b、1c、3a、3b 和 3c)和三唑基团(化合物 2a 至 2e),以分别模拟青霉素类和头孢菌素类的噻唑烷环和二氢噻嗪环。第三,BATSI 的酰胺骨架(对应于 β-内酰胺的 C-6 或 C-7 处的酰胺)也被改为以下生物异构基团:脲(化合物 3b)、硫脲(化合物 3c)和磺酰胺(化合物 4a 和 4b)。在抑制 KPC-2 和 SHV-1 β-内酰胺酶的化合物中,有九种化合物具有 50%的抑制浓度(IC
50
s)≤600 nM。最有效的化合物在 R1 位含有噻吩乙酰基,而对于手性 BATSIs,在 R2 位含有羧基或羟基取代的芳基。活性最高的磺酰胺衍生物化合物 4b 缺少 R2 基团。化合物 2b (S02030) 的活性最高,其酰化率 (
k
2
/
K
)为 1.2 ± 0.2 × 10
4
M
-1
s
-1
和 4.7 ± 0.6 × 10
3
M
-1
s
-1
SHV-1 的抗菌活性。
大肠杆菌
携带
bla
SHV
变体和
bla
KPC-2
或
bla
KPC-3
和临床菌株
肺炎克雷伯菌
和
大肠杆菌
产生不同 A 类 β-内酰胺酶基因的临床菌株。MICs 最多可从 16 毫克/升降至 0.5 毫克/升。