Ogawara Hiroshi
HO Bio Institute, 33-9, Yushima-2, Bunkyo-ku, Tokyo 113-0034, Japan.
Department of Biochemistry, Meiji Pharmaceutical University, 522-1, Noshio-2, Kiyose, Tokyo 204-8588, Japan.
Molecules. 2016 May 10;21(5):605. doi: 10.3390/molecules21050605.
Antibiotic resistance is one of the most serious public health problems. Among bacterial resistance, β-lactam antibiotic resistance is the most prevailing and threatening area. Antibiotic resistance is thought to originate in antibiotic-producing bacteria such as Streptomyces. In this review, β-lactamases and penicillin-binding proteins (PBPs) in Streptomyces are explored mainly by phylogenetic analyses from the viewpoint of self-resistance. Although PBPs are more important than β-lactamases in self-resistance, phylogenetically diverse β-lactamases exist in Streptomyces. While class A β-lactamases are mostly detected in their enzyme activity, over two to five times more classes B and C β-lactamase genes are identified at the whole genomic level. These genes can subsequently be transferred to pathogenic bacteria. As for PBPs, two pairs of low affinity PBPs protect Streptomyces from the attack of self-producing and other environmental β-lactam antibiotics. PBPs with PASTA domains are detectable only in class A PBPs in Actinobacteria with the exception of Streptomyces. None of the Streptomyces has PBPs with PASTA domains. However, one of class B PBPs without PASTA domain and a serine/threonine protein kinase with four PASTA domains are located in adjacent positions in most Streptomyces. These class B type PBPs are involved in the spore wall synthesizing complex and probably in self-resistance. Lastly, this paper emphasizes that the resistance mechanisms in Streptomyces are very hard to deal with, despite great efforts in finding new antibiotics.
抗生素耐药性是最严重的公共卫生问题之一。在细菌耐药性中,β-内酰胺类抗生素耐药性是最普遍且最具威胁的领域。抗生素耐药性被认为起源于产抗生素的细菌,如链霉菌属。在本综述中,主要从自我耐药性的角度通过系统发育分析来探究链霉菌属中的β-内酰胺酶和青霉素结合蛋白(PBPs)。尽管在自我耐药性方面PBPs比β-内酰胺酶更重要,但链霉菌属中存在系统发育多样的β-内酰胺酶。虽然A类β-内酰胺酶大多通过其酶活性检测到,但在全基因组水平上鉴定出的B类和C类β-内酰胺酶基因数量是其两倍到五倍多。这些基因随后可转移至病原菌。至于PBPs,两对低亲和力PBPs可保护链霉菌属免受自身产生的和其他环境β-内酰胺抗生素的攻击。除链霉菌属外,具有PASTA结构域的PBPs仅在放线菌的A类PBPs中可检测到。链霉菌属均不具有带有PASTA结构域的PBPs。然而,在大多数链霉菌属中,一个没有PASTA结构域的B类PBPs和一个带有四个PASTA结构域的丝氨酸/苏氨酸蛋白激酶位于相邻位置。这些B类PBPs参与孢子壁合成复合体,可能也参与自我耐药性。最后,本文强调,尽管在寻找新抗生素方面付出了巨大努力,但链霉菌属中的耐药机制仍极难应对。