Review Article

Antibiotics and antibiotic resistance race: a chronicle of antibiotic discovery against Gram-negative bacteria during 2001-2020: way forward

Abstract

The continuous evolutionary race between antibacterial innovation and antimicrobial resistance (AMR) has become one of the greatest challenges in the management of Gram-negative bacterial infections. Although numerous antibiotics and β-lactam–β-lactamase inhibitor combinations have been introduced since 2000, their clinical utility has been progressively eroded by the rapid emergence and global dissemination of resistance mechanisms, including carbapenemase production, reduced outer membrane permeability, multidrug efflux, target modification, and antibiotic-inactivating enzymes. This review provides a chronological and mechanistic overview of anti-Gram-negative antibiotic development over the past two decades while examining the parallel evolution of bacterial resistance that has limited the therapeutic lifespan of both established and newly approved agents. We critically discuss the mechanisms of action, antibacterial spectrum, pharmacological characteristics, clinical utility, and resistance determinants of recently approved antibiotics, with particular emphasis on therapeutic innovations that overcome conventional resistance barriers, including advanced β-lactam–β-lactamase inhibitor combinations, the siderophore cephalosporin cefiderocol, next-generation tetracyclines, aminoglycosides, and novel bacterial topoisomerase inhibitors. Emerging therapeutic strategies, including investigational antibacterial agents, artificial intelligence-assisted antibiotic discovery, bacteriophage therapy, and CRISPR-based antimicrobial approaches, are also reviewed as potential solutions to the growing challenge of multidrug-resistant Gram-negative pathogens. Collectively, these advances illustrate that successful antibiotic development increasingly depends on innovative target engagement, improved bacterial uptake, and resistance-informed drug design rather than incremental modification of existing scaffolds alone. Ultimately, preserving the clinical effectiveness of new antibiotics will require the integration of antimicrobial stewardship, rapid diagnostics, genomic surveillance, and mechanism-guided drug development to slow the continuing evolutionary arms race between bacterial adaptation and therapeutic innovation.

1. WHO (2019). New report calls for urgent action to avert antimicrobial resistance crisis [Internet]. [cited 2026 Aug 29]. Available from: https://www.who.int/news/item/29-04-2019-new-report-calls-for-urgent-action-to-avert-antimicrobial-resistance-crisis
2. Boucher HW, Talbot GH, Bradley JS, Edwards JE, Gilbert D, Rice LB, et al. Bad Bugs, No Drugs: No ESKAPE! An Update from the Infectious Diseases Society of America. Clin Infect Dis 2009; 48: 1-12.
3. Butler MS, Henderson IR, Capon RJ, Blaskovich MAT. Antibiotics in the clinical pipeline as of December 2022. J Antibiot (Tokyo) 2023; 76: 431-473.
4. Stokes JM, Yang K, Swanson K, Jin W, Cubillos-Ruiz A, Donghia NM, et al. A Deep Learning Approach to Antibiotic Discovery. Cell 2020; 180(4): 688-702.e13.
5. Livermore DM. The need for new antibiotics. Clin Microbiol Infect 2004;10 Suppl 4:1-9.
6. Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021; 372: n71.
7. Shi Z, Zhang J, Tian L, Xin L, Liang C, Ren X, et al. A Comprehensive Overview of the Antibiotics Approved in the Last Two Decades: Retrospects and Prospects. Molecules 2023; 28: 1762.
8. Guimarães T, Nouér SA, Martins RCR, Perdigão Neto LV, Martins WMBS, Narciso Barbosa AC, et al. Ceftazidime-Avibactam as Salvage Therapy for Infections Caused by Enterobacteriales Coresistant to Carbapenems and Polymyxins. Antimicrob Agents Chemother 2019; 63(10): e00528-19.
9. Pfaller MA, Bassetti M, Duncan LR, Castanheira M. Ceftolozane/tazobactam activity against drug-resistant Enterobacteriaceae and Pseudomonas aeruginosa causing urinary tract and intraabdominal infections in Europe: report from an antimicrobial surveillance programme (2012–15). J Antimicrob Chemother 2017; 72: 1386-1395.
10. Lob SH, Hackel MA, Kazmierczak KM, Hoban DJ, Young K, Motyl MR, et al. In vitro activity of imipenem-relebactam against gram-negative bacilli isolated from patients with lower respiratory tract infections in the United States in 2015 – Results from the SMART global surveillance program. Diagn Microbiol Infect Dis 2017; 88: 171-176.
11. Bhowmick T, Weinstein MP. Microbiology of Meropenem-Vaborbactam: A Novel Carbapenem Beta-Lactamase Inhibitor Combination for Carbapenem-Resistant Enterobacterales Infections. Infect Dis Ther 2020; 9: 757-767.
12. Berrazeg M, Jeannot K, Ntsogo Enguéné VY, Broutin I, Loeffert S, Fournier D, et al. Mutations in β-Lactamase AmpC Increase Resistance of Pseudomonas aeruginosa Isolates to Antipseudomonal Cephalosporins. Antimicrob Agents Chemother 2015; 59: 6248-6255.
13. Deroche L, Aranzana-Climent V, Rozenholc A, Prouvensier L, Darnaud L, Grégoire N, et al. Characterization of Pseudomonas aeruginosa resistance to ceftolozane-tazobactam due to ampC and/or ampD mutations observed during treatment using semi-mechanistic PKPD modeling. Antimicrob Agents Chemother 2023; 67(10): e0048023.
14. Shields RK, Chen L, Cheng S, Chavda KD, Press EG, Snyder A, et al. Emergence of Ceftazidime-Avibactam Resistance Due to Plasmid-Borne blaKPC-3 Mutations during Treatment of Carbapenem-Resistant Klebsiella pneumoniae Infections. Antimicrob Agents Chemother 2017; 61(3): e02097-16.
15. Fröhlich C, Sørum V, Thomassen AM, Johnsen PJ, Leiros HKS, Samuelsen Ø. OXA-48-Mediated Ceftazidime-Avibactam Resistance Is Associated with Evolutionary Trade-Offs. Gales AC, editor. mSphere 2019; 4(2): e00024-19.
16. Gaibani P, Giani T, Bovo F, Lombardo D, Amadesi S, Lazzarotto T, et al. Resistance to Ceftazidime/Avibactam, Meropenem/Vaborbactam and Imipenem/Relebactam in Gram-Negative MDR Bacilli: Molecular Mechanisms and Susceptibility Testing. Antibiotics (Basal) 2022; 11: 628.
17. Fraile-Ribot PA, Zamorano L, Orellana R, Del Barrio-Tofiño E, Sánchez-Diener I, Cortes-Lara S, et al. Activity of Imipenem-Relebactam against a Large Collection of Pseudomonas aeruginosa Clinical Isolates and Isogenic β-Lactam-Resistant Mutants. Antimicrob Agents Chemother 2020; 64(2): e02165-19.
18. Rogers TM, Kline EG, Griffith MP, Jones CE, Rubio AM, Squires KM, et al. Mutations in ompK36 differentially impact in vitro synergy of meropenem/vaborbactam and ceftazidime/avibactam in combination with other antibiotics against KPC-producing Klebsiella pneumoniae. JAC Antimicrob Resist 2023; 5(5): dlad113.
19. Gaibani P, Lombardo D, Bussini L, Bovo F, Munari B, Giannella M, et al. Epidemiology of Meropenem/Vaborbactam Resistance in KPC-Producing Klebsiella pneumoniae Causing Bloodstream Infections in Northern Italy, 2018. Antibiotics (Basal) 2021; 10: 536.
20. Ehmann DE, Jahić H, Ross PL, Gu RF, Hu J, Durand-Réville TF, et al. Kinetics of Avibactam Inhibition against Class A, C, and D β-Lactamases. J Biol Chem 2013; 288: 27960-27971.
21. García-Castillo M, García-Fernández S, Gómez-Gil R, Pitart C, Oviaño M, Gracia-Ahufinger I, et al. Activity of ceftazidime-avibactam against carbapenemase-producing Enterobacteriaceae from urine specimens obtained during the infection-carbapenem resistance evaluation surveillance trial (iCREST) in Spain. Int J Antimicrob Agents 2018; 51: 511-555.
22. Ortiz de la Rosa JM, Nordmann P, Poirel L. ESBLs and resistance to ceftazidime/avibactam and ceftolozane/tazobactam combinations in Escherichia coli and Pseudomonas aeruginosa. J Antimicrob Chemother 2019; 74: 1934-1939.
23. Gaibani P, Bianco G, Amadesi S, Boattini M, Ambretti S, Costa C. Increased blaKPC Copy Number and OmpK35 and OmpK36 Porins Disruption Mediated Resistance to Imipenem/Relebactam and Meropenem/Vaborbactam in a KPC-Producing Klebsiella pneumoniae Clinical Isolate. Antimicrob Agents Chemother 2022; 66(5): e0019122.
24. Arca-Suárez J, Vázquez-Ucha JC, Fraile-Ribot PA, Lence E, Cabot G, Martínez-Guitián M, et al. Molecular and biochemical insights into the in vivo evolution of AmpC-mediated resistance to ceftolozane/tazobactam during treatment of an MDR Pseudomonas aeruginosa infection. J Antimicrob Chemother 2020; 75: 3209-3217.
25. Alonso-García I, Vázquez-Ucha JC, Lasarte-Monterrubio C, González-Mayo E, Lada-Salvador P, Vela-Fernández R, et al. Simultaneous and divergent evolution of resistance to cephalosporin/β-lactamase inhibitor combinations and imipenem/relebactam following ceftazidime/avibactam treatment of MDR Pseudomonas aeruginosa infections. J Antimicrob Chemother 2023; 78: 1195-1200.
26. Chalhoub H, Sáenz Y, Nichols WW, Tulkens PM, Van Bambeke F. Loss of activity of ceftazidime-avibactam due to MexAB-OprM efflux and overproduction of AmpC cephalosporinase in Pseudomonas aeruginosa isolated from patients suffering from cystic fibrosis. Int J Antimicrob Agents 2018; 52: 697-701.
27. Tamma PD, Heil EL, Justo JA, Mathers AJ, Satlin MJ, Bonomo RA. Infectious Diseases Society of America 2024 Guidance on the Treatment of Antimicrobial-Resistant Gram-Negative Infections. Clin Infect Dis 2024; ciae403. doi: 10.1093/cid/ciae403
28. Ackley R, Roshdy D, Meredith J, Minor S, Anderson WE, Capraro GA, et al. Meropenem-Vaborbactam versus Ceftazidime-Avibactam for Treatment of Carbapenem-Resistant Enterobacteriaceae Infections. Antimicrob Agents Chemother 2020; 64(5): e02313-19.
29. Krajnc A, Brem J, Hinchliffe P, Calvopiña K, Panduwawala TD, Lang PA, et al. Bicyclic Boronate VNRX-5133 Inhibits Metallo- and Serine-β-Lactamases. J Med Chem 2019; 62: 8544-8556.
30. Bush K, Bradford PA. Interplay between β-lactamases and new β-lactamase inhibitors. Nat Rev Microbiol 2019; 17: 295-306.
31. Hamrick JC, Docquier JD, Uehara T, Myers CL, Six DA, Chatwin CL, et al. VNRX-5133 (Taniborbactam), a Broad-Spectrum Inhibitor of Serine- and Metallo-β-Lactamases, Restores Activity of Cefepime in Enterobacterales and Pseudomonas aeruginosa. Antimicrob Agents Chemother 2020; 64(3): e01963-19.
32. Lomovskaya O, Tsivkovski R, Sun D, Reddy R, Totrov M, Hecker S, et al. QPX7728, An Ultra-Broad-Spectrum B-Lactamase Inhibitor for Intravenous and Oral Therapy: Overview of Biochemical and Microbiological Characteristics. Front Microbiol 2021; 12: 697180.
33. Moya B, Barcelo IM, Bhagwat S, Patel M, Bou G, Papp-Wallace KM, et al. WCK 5107 (Zidebactam) and WCK 5153 Are Novel Inhibitors of PBP2 Showing Potent “β-Lactam Enhancer” Activity against Pseudomonas aeruginosa, Including Multidrug-Resistant Metallo-β-Lactamase-Producing High-Risk Clones. Antimicrob Agents Chemother 2017; 61(6): e02529-16.
34. Sader HS, Mendes RE, Duncan LR, Carvalhaes CG, Castanheria M. Antimicrobial activity of cefepime/zidebactam (WCK 5222), a β-lactam/β-lactam enhancer combination, against clinical isolates of Gram-negative bacteria collected worldwide (2018–19). J Antimicrob Chemother 2022; 77: 2642-2649.
35. Zhanel GG, Golden AR, Zelenitsky S, Wiebe K, Lawrence CK, Adam HJ, et al. Cefiderocol: A Siderophore Cephalosporin with Activity Against Carbapenem-Resistant and Multidrug-Resistant Gram-Negative Bacilli. Drugs 2019; 79: 271-289.
36. Jean SS, Hsueh SC, Lee WS, Hsueh PR. Cefiderocol: a promising antibiotic against multidrug-resistant Gram-negative bacteria. Expert Rev Anti Infect Ther 2019; 17: 307-309.
37. Soriano A, Mensa J. Mechanism of action of cefiderocol. Rev Esp Quimioter 2022; 35 Suppl 2(Suppl 2): 16-19.
38. Sato T, Yamawaki K. Cefiderocol: Discovery, Chemistry, and In Vivo Profiles of a Novel Siderophore Cephalosporin. Clin Infect Dis 2019; 69 (Suppl 7): S538-S543.
39. Nakamura R, Oota M, Matsumoto S, Sato T, Yamano Y. In Vitro Activity and In Vivo Efficacy of Cefiderocol against Stenotrophomonas maltophilia. Antimicrob Agents Chemother 2021; 65(4): e01436-20.
40. Takemura M, Nakamura R, Ota M, Nakai R, Sahm DF, Hackel MA, et al. In vitro and in vivo activity of cefiderocol against Achromobacter spp. and Burkholderia cepacia complex, including carbapenem-non-susceptible isolates. Uhlemann AC, editor. Antimicrob Agents Chemother 2023; 67(12): e0034623.
41. Wunderink RG, Matsunaga Y, Ariyasu M, Clevenbergh P, Echols R, Kaye KS, et al. Cefiderocol versus high-dose, extended-infusion meropenem for the treatment of Gram-negative nosocomial pneumonia (APEKS-NP): a randomised, double-blind, phase 3, non-inferiority trial. Lancet Infect Dis 2021; 21: 213-225.
42. Portsmouth S, Echols R, Toyoizumi K, Tillotson G, Nagata TD. Structured patient interview to assess clinical outcomes in complicated urinary tract infections in the APEKS-cUTI study: pilot investigation. Ther Adv Infect Dis 2021; 8: 20499361211058257.
43. Bassetti M, Echols R, Matsunaga Y, Ariyasu M, Doi Y, Ferrer R, et al. Efficacy and safety of cefiderocol or best available therapy for the treatment of serious infections caused by carbapenem-resistant Gram-negative bacteria (CREDIBLE-CR): a randomised, open-label, multicentre, pathogen-focused, descriptive, phase 3 trial. Lancet Infect Dis 2021; 21: 226-240.
44. Wang Q, Jin L, Sun S, Yin Y, Wang R, Chen F, et al. Occurrence of High Levels of Cefiderocol Resistance in Carbapenem-Resistant Escherichia coli before its Approval in China: a Report from China CRE-Network. Microbiol Spectr 2022; 10(3): e0267021.
45. Nurjadi D, Kocer K, Chanthalangsy Q, Klein S, Heeg K, Boutin S. New Delhi Metallo-beta-Lactamase Facilitates the Emergence of Cefiderocol Resistance in Enterobacter cloacae. Antimicrob Agents Chemother 2022; 66(2): e0201121.
46. Pu D, Zhuo X, Song R, Wang C, Zhao J, Cao B. EnvZ mutation–driven downregulation of catecholate siderophore receptors and concurrent TonB complex repression confer cefiderocol resistance in a KPC-producing ST11-KL64 hypervirulent Klebsiella pneumoniae. Int J Antimicrob Agents 2026; 67: 107693.
47. Bao J, Xie L, Ma Y, An R, Gu B, Wang C. Proteomic and Transcriptomic Analyses Indicate Reduced Biofilm-Forming Abilities in Cefiderocol-Resistant Klebsiella pneumoniae. Front Microbiol 2022; 12: 778190.
48. Huang E, Thompson RN, Moon SH, Keck JM, Lowry MS, Melero J, et al. Treatment-emergent cefiderocol resistance in carbapenem-resistant Acinetobacter baumannii is associated with insertion sequence IS Aba36 in the siderophore receptor pirA. Antimicrob Agents Chemother 2024; 68(7): e0029024.
49. Polani R, De Francesco A, Tomolillo D, Artuso I, Equestre M, Trirocco R, et al. Cefiderocol Resistance Conferred by Plasmid-Located Ferric Citrate Transport System in Klebsiella pneumoniae Carbapenemase – Producing K. pneumoniae. Emerg Infect Dis 2025; 31: 123-124.
50. Poirel L, Sadek M, Kusaksizoglu A, Nordmann P. Co-resistance to ceftazidime-avibactam and cefiderocol in clinical isolates producing KPC variants. Eur J Clin Microbiol Infect Dis 2022; 41: 677-680.
51. Desmoulin A, Sababadichetty L, Kamus L, Daniel M, Feletti L, Allou N, et al. Adaptive resistance to cefiderocol in carbapenem-resistant Acinetobacter baumannii (CRAB): microbiological and clinical issues. Heliyon 2024; 10(9): e30365.
52. Fröhlich C, Sørum V, Tokuriki N, Johnsen PJ, Samuelsen Ø. Evolution of β-lactamase-mediated cefiderocol resistance. J Antimicrob Chemother 2022; 77: 2429-2436.
53. Poirel L, Sadek M, Nordmann P. Contribution of PER-Type and NDM-Type β-Lactamases to Cefiderocol Resistance in Acinetobacter baumannii. Antimicrob Agents Chemother 2021; 65(10): e0087721.
54. Jacob AS, Chong GL, Lagrou K, Depypere M, Desmet S. No in vitro activity of cefiderocol against OXA-427-producing Enterobacterales. J Antimicrob Chemother 2021; 76: 3317-3318.
55. López-Causapé C, Maruri-Aransolo A, Gomis-Font MA, Penev I, Castillo MG, Mulet X, et al. Cefiderocol resistance genomics in sequential chronic Pseudomonas aeruginosa isolates from cystic fibrosis patients. Clin Microbiol Infect 2023; 29(4): 538.e7-538.e13.
56. Teran N, Egge SL, Phe K, Baptista RP, Tam VH, Miller WR. The emergence of cefiderocol resistance in Pseudomonas aeruginosa from a heteroresistant isolate during prolonged therapy. Silverman JA, editor. Antimicrob Agents Chemother 2024; 68(1): e0100923.
57. Stracquadanio S, Nicolosi A, Marino A, Calvo M, Stefani S. Issues with Cefiderocol Testing: Comparing Commercial Methods to Broth Microdilution in Iron-Depleted Medium—Analyses of the Performances, ATU, and Trailing Effect According to EUCAST Initial and Revised Interpretation Criteria. Diagnostics (Basel) 2024; 14: 2318.
58. Tsakri D, Ferous S, Baltas I, Grandjean L, Anastassopoulou C, Tsakris A. The Achilles’ heel of the Trojan Horse? A systematic evaluation of cefiderocol susceptibility testing. J Antimicrob Chemother 2025; 80: 3194-3207.
59. Simner PJ, Palavecino EL, Satlin MJ, Mathers AJ, Weinstein MP, Lewis JS 2nd, et al. Potential of Inaccurate Cefiderocol Susceptibility Results: a CLSI AST Subcommittee Advisory. Richter SS, editor. J Clin Microbiol 2023; 61(4): e0160022.
60. Morris CP, Bergman Y, Tekle T, Fissel JA, Tamma PD, Simner PJ. Cefiderocol Antimicrobial Susceptibility Testing against Multidrug-Resistant Gram-Negative Bacilli: a Comparison of Disk Diffusion to Broth Microdilution. J Clin Microbiol 2020; 59(1): e01649-20.
61. McCreary EK, Heil EL, Tamma PD. New Perspectives on Antimicrobial Agents: Cefiderocol. Antimicrob Agents Chemother 2021; 65(8): e0217120.
62. Lartigue MF, Poirel L, Poyart C, Réglier-Poupet H, Nordmann P. Ertapenem Resistance of Escherichia coli. Emerg Infect Dis 2007; 13: 315–317.
63. Wang X, Zhang X, Zong Z, Yu R, Lv X, Xin J, et al. Biapenem versus meropenem in the treatment of bacterial infections: a multicenter, randomized, controlled clinical trial. Indian J Med Res 2013; 138: 995-1002.
64. Jean SS, Harnod D, Hsueh PR. Global Threat of Carbapenem-Resistant Gram-Negative Bacteria. Front Cell Infect Microbiol 2022; 12: 823684.
65. Terzi HA, Atasoy AR, Aykan SB, Karakece E, Asık G, Ciftci IH. Association of doripenem resistance with OXA-type carbapenemases in Acinetobacter baumannii isolates. Saudi Med J 2016; 37: 43-47.
66. Principe L, D’Arezzo S, Capone A, Petrosillo N, Visca P. In vitro activity of tigecycline in combination with various antimicrobials against multidrug resistant Acinetobacter baumannii. Ann Clin Microbiol Antimicrob 2009; 8: 18.
67. Chen D, Lan H, Yang W, Tian D, Liu Y, Ju L, et al. Comparative in vitro Activity and Clinical Outcomes of Eravacycline, Tigecycline, and Omadacycline Against Carbapenem-Resistant Acinetobacter baumannii and Klebsiella pneumoniae. Infect Drug Resist 2026; 19: 583973.
68. Moore AY, Del Rosso J, Johnson JL, Grada A. Sarecycline: A Review of Preclinical and Clinical Evidence. Clin Cosmet Investig Dermatol 2020; 13: 553-560.
69. Rodvold KA, Pai MP. Pharmacokinetics and Pharmacodynamics of Oral and Intravenous Omadacycline. Clin Infect Dis 2019; 69(Suppl 1): S16–S22.
70. Seifert H, Stefanik D, Sutcliffe JA, Higgins PG. In-vitro activity of the novel fluorocycline eravacycline against carbapenem non-susceptible Acinetobacter baumannii. Int J Antimicrob Agents 2018; 51: 62-64.
71. García P, Guijarro-Sánchez P, Lasarte-Monterrubio C, Muras A, Alonso-García I, Outeda-García M, et al. Activity and resistance mechanisms of the third generation tetracyclines tigecycline, eravacycline and omadacycline against nationwide Spanish collections of carbapenemase-producing Enterobacterales and Acinetobacter baumannii. Biomed Pharmacother 2024; 181: 117666.
72. Lee YT, Chen HY, Yang YS, Chou YC, Chang TY, Hsu WJ, et al. AdeABC Efflux Pump Controlled by AdeRS Two Component System Conferring Resistance to Tigecycline, Omadacycline and Eravacycline in Clinical Carbapenem Resistant Acinetobacter nosocomialis. Front Microbiol 2020; 11: 584789.
73. Demirbas Z, Ozger H, Suzuk-Yildiz S, Bakkaloglu Z, Dizbay M. In Vitro Activity of Plazomicin Against Carbapenem Resistant Klebsiella pneumoniae Strains. Clin Lab 2022; 68. doi:10.7754/Clin.Lab.2021.210936
74. Cox G, Ejim L, Stogios PJ, Koteva K, Bordeleau E, Evdokimova E, et al. Plazomicin retains antibiotic activity against most aminoglycoside modifying enzymes. ACS Infect Dis 2018; 4: 980-987.
75. Golkar T, Bassenden AV, Maiti K, Arya DP, Schmeing TM, Berghuis AM. Structural basis for plazomicin antibiotic action and resistance. Commun Biol 2021; 4: 729.
76. Bradford PA, Miller AA, O’Donnell J, Mueller JP. Zoliflodacin: An Oral Spiropyrimidinetrione Antibiotic for the Treatment of Neisseria gonorrheae, Including multi-drug-resistant isolates. ACS Infect Dis 2020; 6: 1332-1345.
77. Golparian D, Jacobsson S, Sánchez-Busó L, Bazzo ML, Lan PT, Galarza P, et al. GyrB in silico mining in 27 151 global gonococcal genomes from 1928–2021 combined with zoliflodacin in vitro testing of 71 international gonococcal isolates with different GyrB, ParC and ParE substitutions confirms high susceptibility. J Antimicrob Chemother 2023; 78: 150-154.
78. McGuigan A. Zoliflodacin: First approval. Drugs 2026; 86: 963-970.
79. Hackel MA, Karlowsky JA, Sahm DF, West JM, Scangarella-Oman NE. In vitro activity of gepotidacin against urinary tract infection isolates of Enterobacterales, Enterococcus faecalis, and Staphylococcus saprophyticus. Antimicrob Agents Chemother 2025; 69(6): e0029625.
80. Ross JDC, Wilson J, Workowski KA, Taylor SN, Lewis DA, Gatsi S, et al. Oral gepotidacin for the treatment of uncomplicated urogenital gonorrhoea (EAGLE-1): a phase 3 randomised, open-label, non-inferiority, multicentre study. Lancet 2025; 405: 1608-1620.
81. Taylor SN, Morris DH, Avery AK, Workowski KA, Batteiger BE, Tiffany CA, et al. Gepotidacin for the Treatment of Uncomplicated Urogenital Gonorrhea: A Phase 2, Randomized, Dose-Ranging, Single-Oral Dose Evaluation. Clin Infect Dis 2018; 67: 504-512.
82. Zurawski DV, Reinhart AA, Alamneh YA, Pucci MJ, Si Y, Abu-Taleb R, et al. SPR741, an Antibiotic Adjuvant, Potentiates the In Vitro and In Vivo Activity of Rifampin against Clinically Relevant Extensively Drug-Resistant Acinetobacter baumannii. Antimicrob Agents Chemother 2017; 61(12): e01239-17.
83. Zhao CY, Lv Y, Zhu Y, Wei MJ, Liu MY, Ji XW, et al. A First-in-Human Safety, Tolerability, and Pharmacokinetics Study of Benapenem in Healthy Chinese Volunteers. Antimicrob Agents Chemother 2019; 63(3): e02188-18.
84. Bassetti M, Giacobbe DR, Robba C, Pelosi P, Vena A. Treatment of extended-spectrum β-lactamases infections: what is the current role of new β-lactams/β-lactamase inhibitors? Curr Opin Infect Dis 2020; 33: 474-481.
85. Kaye KS, Shorr AF, Wunderink RG, Du B, Poirier GE, Rana K, et al. Efficacy and safety of sulbactam–durlobactam versus colistin for the treatment of patients with serious infections caused by Acinetobacter baumannii–calcoaceticus complex: a multicentre, randomised, active-controlled, phase 3, non-inferiority clinical trial (ATTACK). Lancet Infect Dis 2023; 23: 1072-1084.
86. Le Terrier C, Nordmann P, Sadek M, Poirel L. In vitro activity of cefepime/zidebactam and cefepime/taniborbactam against aztreonam/avibactam-resistant NDM-like-producing Escherichia coli clinical isolates. J Antimicrob Chemother 2023; 78: 1191-1194.
87. Dubey D, Roy M, Shah TH, Bano N, Kulshrestha V, Mitra S, et al. Compassionate use of a novel β-lactam enhancer-based investigational antibiotic cefepime/zidebactam (WCK 5222) for the treatment of extensively-drug-resistant NDM-expressing Pseudomonas aeruginosa infection in an intra-abdominal infection-induced sepsis patient: a case report. Ann Clin Microbiol Antimicrob 2023; 22: 55.
88. Tsai S, Nigo M, Kang D, Baptista RP, Tamma PD, Jacobs E, et al. Cefepime-zidebactam therapy for extensively drug-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae infection as a bridge to liver transplantation. JAC Antimicrob Resist 2025; 7(4): dlaf129.
89. WHO (2020). Global Antimicrobial Resistance and Use Surveillance System (GLASS) Report: Early Implementation 2020. 1st ed. Geneva: World Health Organization [cited 2026 Aug 29]. Available from: https://www.who.int/publications/i/item/9789240005587
90. ICMR. AMR Surveillance Network, Indian Council of Medical Research, 2023 [Annual] [Internet]. India: Indian Council for Medical Research; 2024 Sep [cited 2026-08-29]. Available from: https://www.icmr.gov.in/reports
91. Jault P, Leclerc T, Jennes S, Pirnay JP, Que YA, Resch G, et al. Efficacy and tolerability of a cocktail of bacteriophages to treat burn wounds infected by Pseudomonas aeruginosa (PhagoBurn): a randomised, controlled, double-blind phase 1/2 trial. Lancet Infect Dis 2019; 19: 35-45.
92. Citorik RJ, Mimee M, Lu TK. Sequence-specific antimicrobials using efficiently delivered RNA-guided nucleases. Nat Biotechnol 2014; 32: 1141–1145.
93. Kiga K, Tan XE, Ibarra-Chávez R, Watanabe S, Aiba Y, Sato’o Y, et al. Development of CRISPR-Cas13a-based antimicrobials capable of sequence-specific killing of target bacteria. Nat Commun 2020; 11: 2934.
94. Hamilton TA, Pellegrino GM, Therrien JA, Ham DT, Bartlett PC, Karas BJ, et al. Efficient inter-species conjugative transfer of a CRISPR nuclease for targeted bacterial killing. Nat Commun 2019; 10: 4544.
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IssueVol 18 No 5 (2026) QRcode
SectionReview Article(s)
DOI https://doi.org/10.18502/ijm.v18i5.22853
Keywords
Anti-bacterial agents Gram-negative bacteria Antimicrobial stewardship Beta-lactamases Carbapenem resistance Multidrug resistance

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1.
Joshi P, Makwana N, Barot D, Kamble D, Yadav B, Kharat A. Antibiotics and antibiotic resistance race: a chronicle of antibiotic discovery against Gram-negative bacteria during 2001-2020: way forward. Iran J Microbiol. 2026;18(5):637-654.