Courtney Colleen M, Chatterjee Anushree
Department of Chemical and Biological Engineering and ‡BioFrontiers Institute, 596 UCB, University of Colorado , Boulder, Colorado 80303, United States.
ACS Infect Dis. 2015 Jun 12;1(6):253-63. doi: 10.1021/acsinfecdis.5b00042. Epub 2015 May 26.
The recent surge of drug-resistant superbugs and shrinking antibiotic pipeline are serious challenges to global health. In particular, the emergence of β-lactamases has caused extensive resistance against the most frequently prescribed class of β-lactam antibiotics. Here, we develop novel synthetic peptide nucleic acid-based antisense inhibitors that target the start codon and ribosomal binding site of the TEM-1 β-lactamase transcript and act via translation inhibition mechanism. We show that these antisense inhibitors are capable of resensitizing drug-resistant Escherichia coli to β-lactam antibiotics exhibiting 10-fold reduction in the minimum inhibitory concentration (MIC). To study the mechanism of resistance, we adapted E. coli at MIC levels of the β-lactam/antisense inhibitor combination and observed a nonmutational, bet-hedging based adaptive antibiotic resistance response as evidenced by phenotypic heterogeneity as well as heterogeneous expression of key stress response genes. Our data show that both the development of new antimicrobials and an understanding of cellular response during the development of tolerance could aid in mitigating the impending antibiotic crisis.
近期耐药超级细菌的激增以及抗生素研发管道的萎缩，是对全球健康的严峻挑战。特别是β-内酰胺酶的出现，已导致对最常处方的β-内酰胺类抗生素产生广泛耐药性。在此，我们开发了基于新型合成肽核酸的反义抑制剂，其靶向TEM-1β-内酰胺酶转录本的起始密码子和核糖体结合位点，并通过翻译抑制机制发挥作用。我们表明，这些反义抑制剂能够使耐药大肠杆菌对β-内酰胺类抗生素重新敏感，最低抑菌浓度（MIC）降低10倍。为了研究耐药机制，我们在β-内酰胺/反义抑制剂组合的MIC水平下对大肠杆菌进行适应性培养，并观察到一种基于非突变、风险对冲的适应性抗生素耐药反应，表现为表型异质性以及关键应激反应基因的异质表达。我们的数据表明，开发新的抗菌药物以及了解耐受性形成过程中的细胞反应，都有助于缓解即将到来的抗生素危机。
