Table 6.
Main findings pertinent to the antibacterial activity studies of nitroxoline
| Antibacterial nitroxoline | |||
|---|---|---|---|
| References | Species | Methodology | Findings |
| Kudera et al. (2020) |
Bacillus cereus Clostridium difficile Clostridium perfringens Enterococcus faecalis Salmonella Enteritidis Salmonella Typhimurium Vibrio parahaemolyticus Yersinia enterocolitica Bacteroides fragilis Bifidobacterium adolescentis Bifidobacterium animalis spp. lactis Bifidobacterium bifidum Bifidobacterium breve Bifidobacterium longum Lactobacillus casei Lactobacillus reuteri Lactobacillus rhamnosus |
a) The MICs of nitroxoline and the other test compounds were evaluated against representative strains of the bacteria previously mentioned by the broth microdilution method b) A cytotoxicity assay was carried out to analyze the antiproliferative activity of nitroxoline and the other substances studied against normal and cancerous human intestinal cell lines, using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method c) The selective toxicity calculation was performed to determine which substances would be selective against diarrheagenic and probiotic bacteria strains d) Finally, the correlation between the tested compounds' biological activities and their chemical structures was ascertained via the Principal Component Analysis (PCA) method |
(a) Nitroxoline exhibited moderate to intense inhibitory activity against all diarrheagenic bacteria (-MIC = 12 ± 10 μg/mL). The compound also exhibited intense inhibitory activity against B. cereus, Clostridium species, E. coli, and S. flexneri (MICs = 2–4 µg/mL) |
| Principe et al. (2020) |
Klebsiella pneumoniae Stenotrophomonas maltophilia Chryseobacterium indologenes Elizabethkingia meningoseptica |
a) MICs were determined for nitroxoline and other zinc chelators evaluated, against the bacterial species mentioned, using the broth microdilution method b) The interaction between meropenem and the tested zinc chelators (among them nitroxoline) was evaluated using the double qualitative diffusion-disc method c) Positive interactions, indicated by the diffusion-disc method, were investigated in detail via the checkerboard assay d) A time-kill assay was performed in Cation-Adjusted Müller-Hinton Broth (CAMHB) e) Galleria mellonella larvae were inoculated by injecting bacterial suspensions with an insulin syringe in the left pro-leg region f) Similarly, the toxicity of the test compounds against G. mellonella larvae was determined by injecting specific concentrations of the substances into the animals g) Finally, the ability of the zinc chelating substances to eradicate bacterial infections induced in G. mellonella larvae was evaluated, determining the viability of the larvae 120 h after the experiment |
a) Nitroxoline showed MIC values from 1 to 4 mg/L for all bacterial species, except for K. pneumoniae, against which the disk-diffusion test showed inactivity b) Inoculated in G. mellonella larvae at 128 mg/L, nitroxoline did not increase hemocyte density compared to the larval control c) Nitroxoline showed intrinsic antibacterial activity in vivo, increasing larval survival time (except when infected with K. pneumoniae) beyond 120 h |
| Cherdtrakulkiat et al. (2019) |
Escherichia. coli Klebsiella pneumoniae Providencia rettgeri |
a) The antimicrobial activity of nitroxoline and two analogs of 8-hydroxyquinoline was determined against 56 isolates of the mentioned bacterial species by the microdilution method, recommended by the Clinical Laboratory Standards Institute (CLSI) b) By the same method, the minimum bactericidal concentration (MBC) was determined for nitroxoline and 8-hydroxyquinoline derivatives against representative strains of the mentioned bacterial species c) Also, by the microdilution method recommended by the CLSI, the activity of nitroxoline and the other compounds evaluated was determined in the presence of metal ions (Ca2+, Mg2+, Mn2+, Zn2+, Cu2+, and Fe3+) |
a) Nitroxoline, among all the compounds tested, was the one that presented the highest antibacterial activity against the species of bacteria in the experiment, presenting MICs in the range of 21.03–84.14 µM) |
| Fuchs et al. (2019) | Neisseria gonorrhoeae |
a) Clinical isolates of N. gonorrhoeae were collected between 2015 and 2018 from two German medical centers, Cologne and Bonn. Among these isolates, those with high MICs for penicillin (MIC 0.125 mg/L) were selected, resulting in 27 selected isolates b) The MICs for penicillin and cefotaxime against clinical isolates were determined by agar diffusion gradient (chocolate agar). The susceptibility of N. gonorrhoeae isolates to antimicrobials was interpreted based on EUCAST clinical cut-off points c) The activity of nitroxoline against N. gonorrhoeae was determined by agar dilution and agar disk-diffusion methods |
a) The MICs of nitroxoline against different N. gonorrhoeae strains ranged from 0.125–4 mg/L |
| Fuchs and Hamprecht (2019) |
Klebsiella pneumoniae Escherichia coli Enterobacter cloacae Citrobacter freundii Proteus mirabilis Klebsiella oxytoca Klebsiella aerogenes Raoultella ornithinolytica |
a) The MICs of meropenem, imipenem, and ertapenem were determined against the addressed bacterial species by agar diffusion gradient using MIC test strips b) Finally, the MIC of nitroxoline against representative strains of the bacteria mentioned was determined by agar dilution method |
a) Because the work involves several species of bacteria, it provides a broad notion of the spectrum of action of the substance tested c) Nitroxoline presented MIC values of 1–32 mg/L against representative strains of the bacterial species tested, which denotes optimal broad-spectrum antibacterial activity |
| Li et al. (2019) | Bartonella henselae |
a) The growth curve of B. henselae was determined in a consistent stationary phase of modified Schneider medium, using the SYBR Green method b) The drug exposure assay was performed by resuspending the B. henselae stationary phase (5 days after the viability assay) in Eppendorf and recovering viable cells by centrifugation. Afterward, the resulting cells were seeded on blood agar plates for counting |
a) After exposure of B. henselae stationary phase to nitroxoline, 6% viable cells remained b) The MIC in the range 0.31–0.63 µg/mL confirms that nitroxoline has high potency against B. henselae |
| Valentine-King et al. (2019) |
Ureaplasma parvum Ureaplasma urealyticum Mycoplasma hominis Mycoplasma pneumoniae Mycoplasma genitalium |
a) The MIC for nitroxoline and the other test compounds were determined against the bacterial species previously mentioned, using the broth microdilution method and the agar dilution method b) Similarly, the minimum bactericidal concentration (MBC) was evaluated for nitroxoline and other test compounds against the bacterial species employed, using culture tubes |
a) Nitroxoline proved to be more efficient against species of Ureaplasma spp., against which it presented MIC50 = 3.13 µM and MIC90 = 6.25 µM. Considering Mycoplasma species, nitroxoline presented MIC values of 12.5–50 µM b) Nitroxoline showed bactericidal effect against U. parvum, while it showed bacteriostatic effect for U. urealyticum |
| Hof and Juretschke (2019) |
Klebsiella pneumoniae Proteus mirabilis |
a) Case report: a 68-year-old patient with multi-morbidities contracted rectal colonization by multidrug-resistant bacteria b) After a coughing fit, the patient developed difficulty swallowing and was admitted to the hospital's pulmonology department. On X-ray imaging, however, there were no signs of aspiration pneumonia c) Clinical evaluation provided evidence of symptomatic urinary tract infection, supported by signs of urine turbidity, proteinuria, and massive leukocytosis triggered by an indwelling catheter d) Microbiological examination of midstream urine revealed the presence of two bacteria: Klebsiella pneumoniae and Proteus mirabilis. Susceptibility to both microorganisms was determined by the disc-diffusion test |
a) Performance of the evaluated substances (among which nitroxoline) directly in clinical practice, in their pharmacological parameters b) The antibiogram showed that nitroxoline was the only substance active against both pathogens |
| Sobke et al. (2018) |
Klebsiella pneumoniae Enterococcus faecium Staphylococcus aureus Escherichia coli Proteus mirabilis Enterococcus faecalis |
a) The susceptibility test to nitroxoline (and other studied compounds) was performed against representative strains of the mentioned bacterial species, combining the VITEK®2 system methodology with double disk diffusion b) The susceptibility of the bacterial species to nitroxoline and nitrofurantoin was also tested utilizing disk diffusion c) The MIC for nitroxoline and nitrofurantoin was determined against the mentioned bacterial species by broth microdilution method, as recommended by EUCAST d) Also the researchers evaluated the minimum bactericidal concentration (MBC) for nitrofurantoin and nitroxoline against E. coli, P. mirabilis, and E. faecalis e) Time-kill test was performed for nitrofurantoin and nitroxoline against E. coli, P. mirabilis, and E. faecalis, using concentrations of 10, 50, and 200 mg/L of the compounds for each bacterial species |
a) Among susceptible strains of bacteria, nitroxoline presented MICs in the range of ≤16 mg/L, while this value varied from 16–64 mg/L for resistant strains b) In the time-kill assay, nitroxoline reduced the number of viable cells of representative strains of the different bacterial species by magnitude of ≤ 2 log at a concentration of 10 mg/L c) In artificial urine, the MICs of nitroxoline varied from 0.25–2 mg/L in pH ranges from 5.5 to 7.5 against E. coli |
| Abouelhassan et al. (2017) |
Acinetobacter baumannii Pseudomonas aeruginosa Staphylococcus aureus Staphylococcus epidermidis Enterococcus faecium Escherichia coli |
a) The minimum inhibitory concentration (MIC) for nitroxoline was determined against the different strains of pathogenic bacteria studied using the broth microdilution method b) Using the Calgary device, the minimum concentration for biofilm eradication (MBEC) of nitroxoline was measured against the previously mentioned bacterial species c) The capacity of nitroxoline to remove biofilms of the different bacterial species studied, formed on fragments of pigskin (ex vivo model), was investigated d) MRSA-2 stationary cell death kinetics assay was performed for nitroxoline, against the bacterial species mentioned before e) The minimum biofilm inhibitory concentration (MBIC) for nitroxoline was measured against the different bacterial species |
a) Nitroxoline demonstrated broad-spectrum antibacterial activity, showing MICs of 4.69–6.25 µM for A. baumannii, 12.5 µM for E.coli, 9.38–25 µM for S. aureus, 18.8 µM for S. epidermidis b) Regarding biofilm eradication, nitroxoline was more active against biofilms of A. baumannii (MBEC = 46.9–62.5 µM) and E. coli (MBEC = 62.5 µM) than for biofilms formed by the other bacterial species c) In an ex vivo model of wound infection by bacterial biofilms (with pigskin fragments), nitroxoline reduced the viability of biofilms formed by A. baumannii, E. coli, S. aureus, and S. epidermidis, with a 99% kill rate of viable biofilm cells |
| Cherdtrakulkiat et al. (2016) |
Escherichia coli Klebsiella pneumoniae Serratia marcescens Salmonella Typhimurium Salmonella Choleraesuis Salmonella Enteritidis Shigella dysenteriae Morganella morganii Citrobacter freundii Plesiomonas shigelloides Aeromonas hydrophila Pseudomonas aeruginosa Pseudomonas stutzeri Shewanella putrefaciens Achromobacter xylosoxidans Staphylococcus aureus Staphylococcus epidermidis Micrococcus luteus Enterococcus faecalis Corynebacterium diphtheriae Bacillus subtilis Listeria monocytogenes Bacillus cereus |
a) The antimicrobial activity of nitroxoline and eight derivatives of 8-hydroxyquinoline was determined against the previously mentioned microorganisms using the agar dilution method b) The 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay was performed to determine the antioxidant activity of nitroxoline and other compounds tested c) A cytotoxicity assay was carried out for nitroxoline and other studied substances using the MTT reduction method (3–4,5-dimethyl-thiazol-2-yl-2,5-diphenyltetrazolium bromide) |
a) Nitroxoline exhibited promising antimicrobial activity, evidenced by MIC values between 5.26–84.14 µM, these values being dependent on the species and strain of microorganism tested b) Nitroxoline exhibited low cytotoxicity, which is reflected in the value of CC50 = 88.14 ± 2.11 µM |
| Ancuta et al. (2016) | Staphylococcus aureus |
a) Ceramic disks were prepared and then characterized using air and water weight method b) The ceramic disks were impregnated with nitroxoline and silver ions c) The ceramic discs were incubated with Staphylococcus aureus cultures at 37 °C for 24 h to evaluate the impregnated compounds' antibacterial activity by measuring the resulting halo of inhibition (disc diffusion method) |
a) The nitroxoline-impregnated discs caused a halo of inhibition > 30 mm, an effect that remained even 24 h after removal of the discs from the Petri dish containing S. aureus, demonstrating strong antimicrobial activity |
| Kresken and Körber-Irrgang (2014) | Escherichia coli |
a) The in vitro activity of nitroxoline was determined against 499 E. coli isolates from urine samples from different German laboratories b) MALDI Biotyper (for species confirmation) and susceptibility testing were performed at a central laboratory (Antiinfectives Intelligence) c) MICs for nitroxoline and other tested compounds were determined by the broth microdilution method as recommended by the International Organization for Standardization (ISO) |
a) Nitroxoline showed a constant activity profile among the different isolated strains of E. coli, evidenced by MIC50 = 2 mg/L and MIC90 = 4 mg/L |
| Wagenlehner et al. (2014) |
Escherichia coli Klebsiella pneumoniae Proteus mirabilis Staphylococcus saprophyticus |
a) Six volunteers received 250 mg single dose nitroxoline, or 200 mg trimethoprim, in order to have their urinary inhibitory titers (UITs) and their urinary bactericidal titers (UBT) determined. Three healthy volunteers received 250 mg of nitroxoline three times a day to determine their urinary bactericidal kinetics (UBK) b) The MICs of nitroxoline and trimethoprim were determined by the broth microdilution method against representative strains of the aforementioned bacterial species c)The UIT and UBT of the volunteers were determined via the microdilution method. UBK was determined by bacterial counting at different times d) Finally, urinary concentrations and analyses of metabolites were performed by liquid chromatography and mass spectrometry |
a) Nitroxoline presented MIC value between 2 and 8 mg/L against representative strains of the different species of bacteria mentioned, which denotes high antibacterial activity b) The authors mentioned no serious adverse events related to the drugs administered to the study volunteers |