Title: A Novel Metallo-beta-Lactamase Involved in the Ampicillin Resistance of Streptococcus pneumoniae ATCC 49136 Strain
Authors: Chang, Chia-Yu
Lin, Hui-Jen
Li, Bor-Ran
Li, Yaw-Kuen
分子醫學與生物工程研究所
應用化學系
前瞻跨領域基礎科學中心
技術發展組
Institute of Molecular Medicine and Bioengineering
Department of Applied Chemistry
Center for Interdisciplinary Science
Technology Development Division
Issue Date: 23-May-2016
Abstract: Streptococcus pneumoniae, a penicillin-sensitive bacterium, is recognized as a major cause of pneumonia and is treated clinically with penicillin-based antibiotics. The rapid increase in resistance to penicillin and other antibiotics affects 450 million people globally and results in 4 million deaths every year. To unveil the mechanism of resistance of S. pneumoniae is thus an important issue to treat streptococcal disease that might consequently save millions of lives around the world. In this work, we isolated a streptococci-conserved L-ascorbate 6-phosphate lactonase, from S. pneumoniae ATCC 49136. This protein reveals a metallo-beta-lactamase activity in vitro, which is able to deactivate an ampicillin-based antibiotic by hydrolyzing the amide bond of the beta-lactam ring. The Michaelis parameter (K-m) = 25 mu M and turnover number (k(cat)) = 2 s(-1) were obtained when nitrocefin was utilized as an optically measurable substrate. Through confocal images and western blot analyses with a specific antibody, the indigenous protein was recognized in S. pneumoniae ATCC 49136. The protein-overexpressed S. pneumonia exhibits a high ampicillin-tolerance ability in vivo. In contrast, the protein-knockout S. pneumonia reveals the ampicillin-sensitive feature relative to the wild type strain. Based on these results, we propose that this protein is a membrane-associated metallo-beta-lactamase (MBL) involved in the antibiotic-resistant property of S. pneumoniae.
URI: http://dx.doi.org/10.1371/journal.pone.0155905
http://hdl.handle.net/11536/133764
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0155905
Journal: PLOS ONE
Volume: 11
Issue: 5
Appears in Collections:Articles