An Update on the Clinical Pipelines of New Antibacterial Drugs Developed in China

Antibacterial resistance is a global health threat that requires further concrete action on the part of all countries.In this context,one of the biggest concerns is whether enough new antibacterial drugs are being discovered and developed.Although several high-quality reviews on clinical antibacterial drug pipelines from a global perspective were published recently,none provides comprehensive information on original antibacterial drugs at clinical stages in China.In this review,we summarize the latest progress of novel antibacterial drugs approved for marketing and under clinical evaluation in China since 2019.Information was obtained by consulting official websites,searching commercial databases,retrieving literature,asking personnel from institutions or companies,and other means,and a considerable part of the data covered here has not been included in other reviews.As of June 30,2023,a total of 20 antibacterial projects from 17 Chinese pharmaceutical companies or developers were identified and updated.Among them,two new antibacterial drugs that belong to traditional antibiotic classes were approved by the National Medical Products Administration(NMPA)in China in 2019 and 2021,respectively,and 18 antibacterial agents are in clinical development,with one under regulatory evaluation,five in phase-3,six in phase-2,and six in phase-1.Most of the clinical candidates are new analogs or monocomponents of traditional antibacterial pharmacophore types,including two dual-acting hybrid antibiotics and a recombinant antibacterial protein.Overall,despite there being 17 antibacterial clinical candidates,our analysis indicates that there are still relatively few clinically differentiated antibacterial agents in stages of clinical development in China.Hopefully,Chinese pharmaceutical companies and institutions will develop more innovative and clinically differentiated candidates with good market potential in the future research and development(R&D)of original antibacterial drugs.

Gas sorption and non-Darcy flow in shale reservoirs

Gas sorption and non-Darcy flow are two important issues for shale gas reservoirs. The sorption consists of dissolution and adsorption. Dissolved gas and adsorbed gas are different. The former is dissolved in the shale matrix, while the latter is concentrated near the solid walls of pores. In this paper, the Langmuir equation is used to describe adsorption and Henry’s law is used to describe dissolution. The K coefficient in Henry’s law of 0.052 mmol/(MPa g TOC) is obtained by matching experimental data. The amount of dissolved gas increases linearly when pressure increases. Using only the Langmuir equation without considering dissolution can lead to a significant underestimation of the amount of sorbed gas in shales. For non-Darcy gas flow, the apparent permeability model for free gas is established by combining slip flow and Knudsen flow. For adsorbed gas, the surface diffusion effect is also considered in this model. The surface diffu- sion coefficient is suggested to be of the same scale as the gas self-diffusion coefficient, and the corresponding effective permeability is derived. When 1/ increases,k/ kincreases, but the relationship is not linear as the Klinkenberg effect suggests. The effect of adsorption on the gas flow is significant in nanopores (r≤2 nm). Adsorption increases apparent permeability in shales at low pressures and decreases it at high pressures.

New method for discretization of continuous attributes in rough set theory

A new method for discretization of continuous attributes is put forward to overcome the limitation of the traditional rough sets, which cannot deal with continuous attributes.The method is based on an improved algorithm to produce candidate cut points and an algorithm of reduction based on variable precision rough information entropy. With the guarantee of consistency of decision system, the method can reduce the number of cut points and im- prove efficiency of reduction. Adopting variable precision rough information entropy as measure criterion, it has a good tolerance to noise. Experiments show that the algorithm yields satisfying reduction results.

Endorepellin和neurexin互作促进神经上皮细胞自噬并维持正常神经管发育

Heparan sulfate proteoglycan 2(HSPG2)gene encodes the matrix protein Perlecan,and genetic inactivation of this gene creates mice that are embryonic lethal with severe neural tube defects(NTDs).We discovered rare genetic variants of HSPG2 in 10%cases compared to only 4%in controls among a cohort of 369 NTDs.Endorepellin,a peptide cleaved from the domain V of Perlecan,is known to promote angiogenesis and autophagy in endothelial cells.The roles of enderepellin in neurodevelopment remain unclear so far.Our study revealed that endorepellin can migrate to the neuroepithelial cells and then be recognized and bind with the neuroepithelia receptor neurexin in vivo.Through the endocytic pathway,the interaction of endorepellin and neurexin physiologically triggers autophagy and appropriately modulates the differentiation of neural stem cells into neurons as a blocker,which is necessary for normal neural tube closure.We created knock-in(KI)mouse models with human-derived HSPG2 variants,using sperm-like stem cells that had been genetically edited by CRISPR/Cas9.We realized that any HSPG2 variants that affected the function of endorepellin were considered pathogenic causal variants for human NTDs given that the severe NTD phenotypes exhibited by these KI embryos occurred in a significantly higher response frequency compared to wildtype embryos.Our study provides a paradigm for effectively confirming pathogenic mutations in other genetic diseases.Furthermore,we demonstrated that using autophagy inhibitors at a cellular level can repress neuronal differentiation.Therefore,autophagy agonists may prevent NTDs resulting from failed autophagy maintenance and neuronal over-differentiation caused by deleterious endorepellin variants.

Hypericin enhances β-lactam antibiotics activity by inhibiting sarA expression in methicillinresistant Staphylococcus aureus

Bacteremia is a life-threating syndrome often caused by methicillin-resistant Staphylococcus aureus(MRSA).Thus,there is an urgent need to develop novel approaches to successfully treat this infection.Staphylococcal accessory regulator A(SarA),a global virulence regulator,plays a critical role in pathogenesis andβ-lactam antibiotic resistance in Staphylococcus aureus.Hypericin is believed to act as an antibiotic,antidepressant,antiviral and non-specific kinase inhibitor.In the current study,we investigated the impact of hypericin onβ-lactam antibiotics susceptibility and mechanism(s)of its activity.We demonstrated that hypericin significantly decreased the minimum inhibitory concentrations ofβ-lactam antibiotics(e.g.,oxacillin,cefazolin and nafcillin),biofilm formation and fibronectin binding in MRSA strain JE2.In addition,hypericin significantly reduced sarA expression,and subsequently decreased mecAy and virulence-related regulators(e.g.,agr RNAIII)and genes(e.g.,fnbA and hla)expression in the studied MRSA strain.Importantly,the in vitro synergistic effect of hypericin withβ-lactam antibiotic(e.g.,oxacillin)translated into in vivo therapeutic outcome in a murine MRSA bacteremia model.These findings suggest that hypericin plays an important role in abrogation ofβ-lactam resistance againstMRSA through sarA inhibition,and may allow us to repurpose the use ofβ-lactam antibiotics,which are normally ineffective in the treatment of MRSA infections(e.g.,oxacillin).

In vitro and in vivo activity of D-serine in combination with β-lactam antibiotics against methicillin-resistant Staphylococcus aureus

As D-amino acids play important roles in the physiological metabolism of bacteria,combination of D-amino acids with antibiotics may provide synergistic antibacterial activity. The aim of the study was to evaluate in vitro and in vivo activity of D-serine alone and in combination withβ-lactams against methicillin-resistant Staphylococcus aureus(MRSA) strains, and to explore the possible sensitization mechanisms. The activity of D-serine, β-lactams alone and in combinations was evaluated both in vitro by standard MICs, time–kill curves and checkerboard assays, and in vivo by murine systemic infection model as well as neutropenic thigh infection model. An in vitro synergistic effect was demonstrated with the combination of D-serine and β-lactams against MRSA standard and clinical strains.Importantly, the combinations enhanced the therapeutic efficacy in the animal models as compared toβ-lactam alone groups. Initial mechanism study suggested possible revision of D-alanine-D-alanine residue to D-alanine-D-serine in peptidoglycan by adding of D-alanine in the medium, which may cause decreased affinity to PBPs during transpeptidation. In conclusion, D-serine had synergistic activity in combination with β-lactams against MRSA strains both in vitro and in vivo. Considering the relatively good safety of D-serine alone or in combination with β-lactams, D-serine is worth following up as new anti-MRSA infection strategies.

Efficient generation of the mouse model with a defined point mutation through haploid cell-mediated gene editing

Generation of mouse models carrying a defined point mutation,especially disease-related point mutations,is of considerable interest for research in biology and medicine.The standard method based on embryonic stem cell（ESC）-mediated homologous recombination（HR）is time-and labor-consuming.

Genetic basis of high level aminoglycoside resistance in Acinetobacter baumannii from Beijing,China

The objective of this study was to investigate the genetic basis of high level aminoglycoside resistance in Acinetobacter baumannii clinical isolates from Beijing,China.173 A.baumannii clinical isolates from hospitals in Beijing from 2006 to 2009 were first subjected to high level aminoglycoside resistance(HLAR,MIC to gentamicin and amikacin>512 mg/mL)phenotype selection by broth microdilution method.The strains were then subjected to genetic basis analysis by PCR detection of the aminoglycoside modifying enzyme genes(aac(3)-Ⅰ,aac(3)-Ⅱc,aac(60)-Ⅰb,aac(60)-Ⅱ,aph(4)-Ⅰa,aph(30)-Ⅰ,aph(30)-Ⅱb,aph(30)-Ⅲa,aph(30)-Ⅵa,aph(2″)-Ⅰb,aph(2″)-Ⅰc,aph(2″)-Ⅰd,ant(2″)-Ⅰa,ant(3″)-Ⅰand ant(40)-Ⅰa)and the 16S rRNA methylase genes(armA,rmtB and rmtC).Correlation analysis between the presence of aminoglycoside resistance gene and HLAR phenotype were performed by SPSS.Totally 102(58.96%)HLAR isolates were selected.The HLAR rates for year 2006,2007,2008 and 2009 were 52.63%,65.22%,51.11%and 70.83%,respectively.Five modifying enzyme genes(aac(3)-Ⅰ,detection rate of 65.69%;aac(60)-Ⅰb,detection rate of 45.10%;aph(30)-Ⅰ,detection rate of 47.06%;aph(30)-Ⅱb,detection rate of 0.98%;ant(3″)-Ⅰ,detection rate of 95.10%)and one methylase gene(armA,detection rate of 98.04%)were detected in the 102 A.baumannii with aac(3)-Ⅰ+aac(60)-Ⅰ+þant(3″)-Ⅰ+armA(detection rate of 25.49%),aac(3)-Ⅰ+aph(30)-Ⅰ+ant(3″)-Ⅰ+armA(detection rate of 21.57%)and ant(3″)-Ⅰ+armA(detection rate of 12.75%)being the most prevalent gene profiles.The values of chi-square tests showed correlation of armA,ant(3″)-Ⅰ,aac(3)-Ⅰ,aph(30)-Ⅰand aac(60)-Ⅰb with HLAR.armA had significant correlation(contingency coefficient 0.685)and good contingency with HLAR(kappa 0.940).The high rates of HLAR may cause a serious problem for combination therapy of aminoglycoside with β-lactams against A.baumannii infections.As armA was reported to be able to cause high level aminoglycoside resistance to most of the clinical important aminoglycosides(gentamicin,amikacin,tobramycin,etc),the function of aminoglycoside modifying enzyme gene(s)in A.baumannii carrying armA deserves further investigation.

Polymyxin resistance caused by large-scale genomic inversion due to IS26 intramolecular translocation in Klebsiella pneumoniae

Polymyxin B and polymyxin E(colistin)are presently considered the last line of defense against human infections caused by multidrug-resistant Gram-negative organisms such as carbapenemase-producer Enterobacterales,Acinetobacter baumannii,and Klebsiella pneumoniae.Yet resistance to this last-line drugs is a major public health threat and is rapidly increasing.Polymyxin S2(S2)is a polymyxin B analogue previously synthesized in our institute with obviously high antibacterial activity and lower toxicity than polymyxin B and colistin.To predict the possible resistant mechanism of S2for wide clinical application,we experimentally induced bacterial resistant mutants and studied the preliminary resistance mechanisms.Mut-S,a resistant mutant of K.pneumoniae ATCC BAA-2146(Kpn2146)induced by S2,was analyzed by whole genome sequencing,transcriptomics,mass spectrometry and complementation experiment.Surprisingly,large-scale genomic inversion(LSGI)of approximately 1.1 Mbp in the chromosome caused by IS26mediated intramolecular transposition was found in Mut-S,which led to mgrB truncation,lipid A modification and hence S2resistance.The resistance can be complemented by plasmid carrying intact mgrB.The same mechanism was also found in polymyxin B and colistin induced drug-resistant mutants of Kpn2146(Mut-B and Mut-E,respectively).This is the first report of polymyxin resistance caused by IS26 intramolecular transposition mediated mgrB truncation in chromosome in K.pneumoniae.The findings broaden our scope of knowledge for polymyxin resistance and enriched our understanding of how bacteria can manage to survive in the presence of antibiotics.

Evolution and development of potent monobactam sulfonate candidate IMBZ18g as a dual inhibitor against MDR Gram-negative bacteria producing ESBLs

A series of new monobactam sulfonates is continuously synthesized and evaluated for their antimicrobial efficacies against Gram-negative bacteria.Compound 33a(IMBZ18G)is highly effective in vitro and in vivo against clinically intractable multi-drug-resistant(MDR)Gram-negative strains,with a highly druglike nature.The checkerboard assay reveals its significant synergistic effect withβ-lactamase inhibitor avibactam,and the MIC values against MDR enterobacteria were reduced up to 4—512folds.X-ray co-crystal and chemoproteomic assays indicate that the anti-MDR bacteria effect of 33a results from the dual inhibition of the common PBP3 and some class A and Cβ-lactamases.Accordingly,preclinical studies of 33a alone and 33a-avibactam combination as potential innovative candidates are actively going on,in the treatment ofβ-lactamase-producing MDR Gram-negative bacterial infections.

Discussion of liquid threshold pressure gradient

Some authors believe that a minimum pressure gradient(called threshold pressure gradient(TPG))is required before a liquid starts to flow in a porous medium.In a tight or shale oil formation,this TPG phenomenon becomes more important,as it is more difficult for a fluid to flow.In this paper,experimental data on TPG published in the literature are carefully reviewed.What we found is that a very low flow velocity corresponding to a very low pressure gradient cannot be measured in the experiments.Experiments can only be done above some measurable flow velocities.If these flow velocities and their corresponding pressure gradients are plotted in an XY plot and extrapolated to zero velocity,a non-zero pressure gradient corresponds to this zero velocity.This non-zero pressure gradient is called threshold pressure gradient in the literature.However,in the regime of very low velocity and very low pressure gradient,the data gradually approach to the origin of the plot,demonstrating a non-linear relationship between the pressure gradient and the velocity.But the data do not approach to a point of zero velocity and a threshold pressure gradient.Therefore,the concept of threshold pressure gradient is a result of data misinterpretation of available experimental data.The correct interpretation is that there are two flow regimes:nonlinear flow regime(non-Darcy flow regime)when the pressure gradients are low,and linear flow regime(Darcy flow regime)when the pressure gradient is intermediate or high.The nonlinear flow regime starts from the origin point.As the pressure gradient is increased,the curve becomes a straight line demonstrating the linear flow regime.We have verified our views by first analyzing the causes of non-Darcy flow,and then systematically analyzed typical experimental data and correlations in the literature.We conclude that TPG does not exist.We also use several counter examples to support our conclusion.

Pore scale numerical investigation of counter-current spontaneous imbibition in multi-scaled pore networks

The multi-scaled pore networks of shale or tight reservoirs are considerably different from the conventional sandstone reservoirs.After hydraulic fracturing treatment,the spontaneous imbibition process plays an important role in the productivity of the horizontal wells.Applying the color-gradient model of Lattice Boltzmann Method(LBM)accelerated with parallel computing,we studied the countercurrent spontaneous imbibition process in two kinds of pore structures with different interlacing distributions of large and small pores.The effect of geometry configuration of pore arrays with different pore-scale and the capillary number Ca on the mechanism of counter-current spontaneous imbibition as well as the corresponding oil recovery factor are studied.We found that the wetting phase tends to invade the small pore array under small Ca in both types of geometry configurations of different pore arrays of four pore arrays zones.The wetting phase also tends to invade the pore array near the inlet for injecting the wetting phase no matter if it is a large pore array or small pore array except for the situation when the Ca is large to a certain value.In this situation,the small pore arrays show resistance to the wetting phase,so the wetting phase doesn't invade the small pore near the inlet,but invades the large pore preferentially.Both the geometry configurations of different pore arrays and Ca have a significant effect on the oil recovery factor.This work will help to solve the doubt about the selectivity of the multi-scaled pores of the wetting phase and the role of pores with different sizes in imbibition and oil draining in countercurrent spontaneous imbibition processes.

Human embryos in a dish - modeling early embryonic development with pluripotent stem cells

Stem cell-based embryo models present new opportunities to study early embryonic development.In a recent study,Kagawa et al.identified an approach to create human pluripotent stem cell-based blastoids that resemble the human blastocysts.These blastoids efficiently generated analogs of the EPI,TE,PrE lineages with transcriptomes highly similar to those found in vivo.Furthermore,the formation of these lineages followed the same sequence and pace of blas-tocyst development,and was also dependent on the same pathways required for lineage specification.Finally,the blastoids were capable of attaching to stimulated endometrial cells to mimic the process of implantation.While more comprehensive analysis is needed to confirm its validity and usefulness,this new blastoid system presents the latest development in the attempt to model early human embryogenesis in vitro.