College of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.
Key Laboratory of Marine Ecosystem and Biogeochemistry, Second Institute of Oceanography, State Oceanic Administration, Hangzhou, China.
Sci Rep. 2018 Jan 16;8(1):803. doi: 10.1038/s41598-018-19279-0.
Metallo-β-lactamases (MBLs) are a group of enzymes that can inactivate most commonly used β-lactam-based antibiotics. Among MBLs, New Delhi metallo-β-lactamase-1 (NDM-1) constitutes an urgent threat to public health as evidenced by its success in rapidly disseminating worldwide since its first discovery. Here we report the biochemical and genetic characteristics of a novel MBL, ElBla2, from the marine bacterium Erythrobacter litoralis HTCC 2594. This enzyme has a higher amino acid sequence similarity to NDM-1 (56%) than any previously reported MBL. Enzymatic assays and secondary structure alignment also confirmed the high similarity between these two enzymes. Whole genome comparison of four Erythrobacter species showed that genes located upstream and downstream of elbla2 were highly conserved, which may indicate that elbla2 was lost during evolution. Furthermore, we predicted two prophages, 13 genomic islands and 25 open reading frames related to insertion sequences in the genome of E. litoralis HTCC 2594. However, unlike NDM-1, the chromosome encoded ElBla2 did not locate in or near these mobile genetic elements, indicating that it cannot transfer between strains. Finally, following our phylogenetic analysis, we suggest a reclassification of E. litoralis HTCC 2594 as a novel species: Erythrobacter sp. HTCC 2594.
金属β-内酰胺酶（MBLs）是一组能够使大多数常用的β-内酰胺类抗生素失活的酶。在 MBLs 中，新德里金属β-内酰胺酶-1（NDM-1）构成了对公共卫生的紧迫威胁，因为自首次发现以来，它在全球迅速传播的成功证明了这一点。在这里，我们报告了海洋细菌Erythrobacter litoralis HTCC 2594 中一种新型 MBL ElBla2 的生化和遗传特征。该酶与 NDM-1（56%）的氨基酸序列相似度高于以前报道的任何 MBL。酶促测定和二级结构比对也证实了这两种酶之间的高度相似性。对四种 Erythrobacter 物种的全基因组比较表明，elbla2 上下游的基因高度保守，这可能表明 elbla2 在进化过程中丢失了。此外，我们预测了两个噬菌体、13 个基因组岛和 25 个与插入序列相关的开放阅读框在 E. litoralis HTCC 2594 的基因组中。然而，与 NDM-1 不同，染色体编码的 ElBla2 并不位于或靠近这些移动遗传元件中，表明它不能在菌株之间转移。最后，根据我们的系统发育分析，我们建议将 E. litoralis HTCC 2594 重新分类为一个新种：Erythrobacter sp. HTCC 2594。
