The lack of effective first-line antibiotic treatments against Neisseria gonorrhoeae, and the worldwide dissemination of resistant strains, are the main drivers of a worsening global health crisis. β-lactam antibiotics have been the backbone of therapeutic armamentarium against gonococci. However, we are lacking critical insights to design rationally optimized therapies. In the present work, we generated the first PBP-binding data set on 18 currently available and clinically relevant β-lactams and 4 β-lactamase inhibitors in two N. gonorrhoeae ATCC type collection strains, 19424 and 49226 (PBP2 type XXII and A39T change in mtrR). PBP binding (IC50) was determined via the Bocillin FL binding assay in isolated membrane preparations. Three clusters of differential PBP IC50s were identified and were mostly consistent across both strains, but with quantitative differences. Carbapenems were coselective for PBP2 and PBP3 (0.01 to 0.03 mg/L). Third- and fourth-generation cephalosporins cefixime, cefotaxime, ceftazidime, cefepime, and ceftriaxone showed the lowest IC50 values for PBP2 (0.01 mg/L), whereas cefoxitin, ceftaroline, and ceftolozane required higher concentrations (0.04 to >2 mg/L). Aztreonam was selective for PBP2 in both strains (0.03 to 0.07 mg/L); amdinocillin bound this PBP at higher concentrations (1.33 to 2.94 mg/L). Penicillins specifically targeted PBP2 in strain ATCC 19424 (0.02 to 0.19 mg/L) and showed limited inhibition in strain ATCC 49226 (0.01 to >2 mg/L). Preferential PBP2 binding was observed by β-lactam-based β-lactamase inhibitors sulbactam and tazobactam (1.07 to 6.02 mg/L); meanwhile, diazabicyclooctane inhibitors relebactam and avibactam were selective for PBP3 (1.27 to 5.40 mg/L). This data set will set the bar for future studies that will help the rational use and translational development of antibiotics against multidrug-resistant (MDR) N. gonorrhoeae.

B.M. received funds from a RADIX17/3-1 fellowship and RADIX17/3-2 grant, programs within the FUTURMed project IdISBa Research Institute of Health Sciences of the Balearic Islands, Hospital Universitario Son Espases, Palma, Spain. Call funded by the 2017 annual plan of the sustainable tourism tax. Govern de les Illes Balears, by the Miguel Servet Research Contract Program CP20/00138 from the National Institutes of Health Carlos III (ISCIII) and by the Agencia Estatal de Investigación (AEI - State Research Agency), Spain, through the Plan Estatal de Investigación Científica PROYECTOS DE I+D+i PID2020-112654RB-I00 / AEI / 10.13039/501100011033. The assay development part of this work was supported by the award R01AI136803 to B.M. from the National Institute of Allergy and Infectious Diseases (NIAID). The content of this paper is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Allergy and Infectious Diseases or the National Institutes of Health (NIH). A.O. received funds from the Ministerio de Economía y Competitividad of Spain, Instituto de Salud Carlos III, cofinanced by European Regional Development Fund “A Way to Achieve Europe” ERDF, through the Spanish Network for the Research in Infectious Diseases (RD16/0016). A.O. has received fees as speaker and/or research grants from MSD, Pfizer, and Wockhardt.

Contains: Figures S1-S2 and Table S1.

Peer reviewed