meropenem and nitroxoline

Carbapenemases such as metallo-β-lactamases (MBLs) are spreading among Gram-negative bacterial pathogens. Infections due to these multidrug-resistant bacteria constitute a major global health challenge. Therapeutic strategies against carbapenemase producing bacteria include β-lactamase inhibitor combinations. Nitroxoline is a broad-spectrum antibiotic with restricted indication for urinary tract infections. In this study, we report on nitroxoline as an inhibitor of MBLs. We investigate the structure-activity relationships of nitroxoline derivatives considering in vitro MBL inhibitory potency in a fluorescence based assay using purified recombinant MBLs, NDM-1 and VIM-1. We investigated the most potent nitroxoline derivative in combination with imipenem against clinical isolates as well as transformants producing MBL by broth microdilution and time-kill kinetics. Our findings demonstrate that nitroxoline derivatives are potent MBL inhibitors and in combination with imipenem overcome MBL-mediated carbapenem resistance.

Topics: Anti-Bacterial Agents; beta-Lactamase Inhibitors; beta-Lactamases; Cell Survival; Cells, Cultured; Dose-Response Relationship, Drug; Gram-Negative Bacteria; Humans; Microbial Sensitivity Tests; Molecular Structure; Nitroquinolines; Recombinant Proteins; Structure-Activity Relationship

The old antimicrobial nitroxoline is currently repurposed for oral treatment of uncomplicated urinary tract infections (UTIs).. To investigate the in vitro activity of nitroxoline against carbapenem-resistant Acinetobacter baumannii (CRAb).. From an international collection of previously well-characterized clinical A. baumannii isolates, 34 isolates from urinary tract sources with different carbapenem-resistance mechanisms were selected. Nitroxoline activity was analysed with broth microdilution (BMD), disc diffusion (DD) and within an in vitro biofilm model. MICs of meropenem and imipenem were assessed with BMD. Susceptibility to ciprofloxacin and trimethoprim/sulfamethoxazole was investigated using DD. Escherichia coli ATCC 25922 and A. baumannii NCTC 13304 were used for quality control.. All isolates were carbapenem resistant (MIC90 >32 mg/L for meropenem and imipenem) and most isolates were resistant to ciprofloxacin (33/34) and trimethoprim/sulfamethoxazole (31/34). Nitroxoline yielded MIC50/90 values of 2/2 mg/L (MIC range 1-2 mg/L) and inhibition zone diameters ranging from 20 to 26 mm. In contrast, for definite eradication of biofilm-associated CRAb in vitro, higher nitroxoline concentrations (≥16 to ≥128 mg/L) were necessary for all isolates.. Nitroxoline showed excellent in vitro activity against a collection of CRAb despite high resistance rates to other antimicrobials for parental and oral therapy of A. baumannii UTI. Currently, nitroxoline is recommended for the treatment of uncomplicated UTI in Germany with a EUCAST breakpoint limited to uncomplicated UTI and E. coli (S ≤16 mg/L). Nitroxoline could be a promising drug for oral treatment of lower UTI caused by CRAb. More data are warranted to correlate these findings with in vivo success rates.

Topics: Acinetobacter baumannii; Acinetobacter Infections; Anti-Bacterial Agents; Carbapenems; Ciprofloxacin; Escherichia coli; Humans; Imipenem; Meropenem; Microbial Sensitivity Tests; Nitroquinolines; Sulfamethoxazole; Trimethoprim; Urinary Tract; Urinary Tract Infections

Infections caused by carbapenemase-producing Enterobacterales (CPE) constitute a major global health concern and are associated with increased morbidity and mortality. Nitroxoline is an old antibiotic, which has recently been re-launched for the treatment of uncomplicated urinary tract infection. Because of low resistance rates it could be an interesting option for treatment of MDR isolates, yet data on CPE susceptibility are scarce.. To analyse the in vitro activity of nitroxoline against CPE.. MICs of nitroxoline were determined by agar dilution for a collection of well-characterized carbapenemase producers (n = 105), producing OXA-48-like (n = 36), VIM (n = 21), IMI (n = 9), IMP (n = 6), NDM (n = 22), KPC (n = 11), OXA-58 (n = 2) and GES (n = 2). For comparison, MICs of ertapenem, imipenem and meropenem were determined by agar gradient diffusion.. For all 105 isolates, the MIC50/90 of nitroxoline was 8/16 mg/L. All Escherichia coli isolates (30/30, 100%) showed low MICs of 2-8 mg/L and were susceptible to nitroxoline. MICs of 32 mg/L were recorded for five isolates of VIM- and IMI-producing Enterobacter cloacae (n = 3) and OXA- and VIM-producing Klebsiella pneumoniae (n = 2).. Nitroxoline exhibited excellent in vitro activity against most isolates producing common and rare carbapenemases. If the current EUCAST susceptibility breakpoint of ≤16 mg/L for E. coli in uncomplicated urinary tract infections was applied, 95.2% (100/105) of isolates would be classified as susceptible. Nitroxoline could therefore be an alternative oral option for treatment of uncomplicated urinary tract infections caused by CPE.

Topics: Anti-Infective Agents, Urinary; Carbapenem-Resistant Enterobacteriaceae; Enterobacter cloacae; Escherichia coli; Humans; Imipenem; Klebsiella pneumoniae; Meropenem; Microbial Sensitivity Tests; Nitroquinolines