Cell Milestones . . . Breaking the bottleneck of a century-old research and discovering new Gram-negative antibiotics are expected to overcome global resistance problems.

The rise of inature antibiotic resistance and the decline in the number of new antibiotics have caused a global health crisis.of particular concern is that no new antibiotic class has been approved for the treatment of Gram-negative pathogens for decades.on June 3, 2020, the team of zimer Gitai of Princeton University published the title "a dual mechanism antibacterial kills gram negative bacterium and avoides drug" online in cell This study characterized a compound sch-79797, which killed Gram-negative and Gram-positive bacteria through a unique dual targeting mechanism (MOA), with a very low frequency of drug resistance.in order to characterize its MOA, this study combines quantitative imaging, proteomics, genetics, metabonomics and cell-based detection methods.this study shows that sch-79797 has two independent cell targets, folate metabolism and bacterial membrane integrity, and is superior to combination therapy in killing methicillin-resistant Staphylococcus aureus (MRSA) persistence agents.based on the molecular core of sch-79797, we developed a derivative of irestin-16 with enhanced efficacy, and showed its efficacy against Neisseria gonorrhoeae in a mouse vaginal infection model. Br / > the possibility that this combination of antibiotics on a single pathogen is not fully recognized.in the 30 years after the discovery of penicillin in 1929, more than 20 unique antibiotics were characterized.however, the combination of scientific and economic factors has slowed down the discovery and development of these life-saving molecules, so that only six new classes of antibiotics have been approved in the past 20 years, none of which is active against Gram-negative bacteria.the decline in the discovery of new antibiotic categories, coupled with the evolution of multidrug-resistant bacteria and the horizontal shift of drug-resistant mechanisms, has created a public health crisis that is expected to escalate only in the next few years.recent efforts have begun to re energize antibiotic research, but most new antibiotics work through mechanisms similar to those of traditional antibiotics.for example, flunafloxacin, a fluoroquinolone antibiotic, has recently been approved for the treatment of ear infections caused by Pseudomonas aeruginosa and is more effective than other fluoroquinolones because it can maintain its potency in acidic environments.the latest discovery of teixoactin, a natural product, suggests that it is possible to find compounds that selectively kill bacteria but are not susceptible to drug resistance. However, teixobactin only affected Gram-positive bacteria.recently, another natural product, darobactin, has been found specifically for Gram-negative bacteria, but it is relatively easy to achieve resistance to darobactin through Bama mutation.therefore, there is still an urgent need to characterize novel antibiotics with different mechanisms of action (MOA), especially for Gram-negative bacteria with low resistance frequency.the ideal antibiotics are difficult to produce resistance, can kill Gram-positive and Gram-negative bacteria, and are easy to obtain.it is important to note that although antibiotics that are not easily resistant to antibiotics are clinically attractive, the selection of resistant mutants is the most commonly used method to characterize MOA, which makes the characterization of new antibiotics without resistant mutants a major challenge.therefore, a drug-free method for de novo characterization of antibiotic MOA is also needed. here, the study describes a compound sch-79797, which has bactericidal effects on both Gram-negative and Gram-positive bacteria, including clinically important bacterial pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Neisseria gonorrhoeae and Acinetobacter baumannii, showing no signs of resistance. in animal host model, sch-79797 blocked the low toxicity of Acinetobacter baumannii to the host at the dose required for effective antibiotic activity. in order to quickly and effectively classify the MOA of sch-79797, a variant of the recently described quantitative imaging based method called bacterial cytology analysis (BCP) was used. this work shows that sch-79797 works through a mechanism different from that of most known antibiotics. in the case that the resistant mutants could not be evolved, thermal proteome analysis, crispri genetic sensitivity analysis and metabonomics analysis were used to characterize the MOA of sch-7979797. using this multidimensional systematic approach, the target of sch-79797 was determined as dihydrofolate reductase and bacterial membrane. Classic enzymology, membrane permeability and polarization analysis confirmed the target identified by high-throughput method. by analyzing the derivatives of sch-79797 structure, it is proved that the two active groups of the compound can be distinguished. finally, the study described iresistin-16 (irs-16), a derivative of sch-79797, with enhanced potency and showed efficacy in a mouse model of Neisseria gonorrhoeae. therefore, the findings identify and characterize promising antibiotic candidates and provide a potential roadmap for future antibiotic discovery. reference message: