Urinary concentrations and antibacterial activities of nitroxoline at 250 milligrams versus trimethoprim at 200 milligrams against uropathogens in healthy volunteers

Combinatory Effect of Nitroxoline and Gentamicin in the Control of Uropathogenic Enterococci Infections

Enterococcus faecalis, responsible for a majority of human and nosocomial enterococcal infections, is intrinsically resistant to aminoglycoside antibiotics (such as gentamicin, GEN), which must be used in a combined therapy to be effective. Nitroxoline (NTX) is an old antibiotic, underused for decades, but rediscovered now in an era of growing antibiotic resistance. In this in vitro study, the types of interactions between NTX and GEN on 29 E. faecalis strains were analyzed with an aim to find synergistic antimicrobial and antiadhesion combinations. Transmission electron microscopy (TEM) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used to analyze changes in cell morphology and bacterial proteome after monotreatments and combined treatments. The results showed the synergistic effect for six combinations on eight strains, including the ATCC29212, and an additive effect for most strains. Combinations causing a complete inhibition of adhesion were established. Cell membrane integrity was affected by NTX, while combined NTX/GEN treatment caused dramatic changes in cell morphology. Upregulation of the expression of many proteins was established, with some emerging only after combined treatment. The results strongly imply that NTX has the potential for use in combined therapy with GEN against enterococci and it could further provide a substantial contribution to an ongoing fight against antimicrobial resistance and nosocomial infections.

Nitroxoline: treatment and prevention of urinary tract infections from the urologist's perspective

Introduction

Nitroxoline is an old antimicrobial agent with a broad spectrum of pharmacological applications and a unique mechanism of action. However, its use in the treatment and prevention of urinary tract infections (UTIs) has not been popular in the recent past. Recently, nitroxoline is gaining interest, due to frequent drug-resistance in uropathogens. Unfortunately, there are few modern clinical trials assessing this antibiotic. Also, older researchers often do not meet current scientific standards. This review seeks to provide a comprehensive overview of nitroxoline as a viable option in treating uncomplicated lower UTIs.

Material and methods

A comprehensive literature search regarding the use of nitroxoline in UTIs was conducted using Pubmed, Cochrane Library and Embase databases. A cross-reference search was also performed. Case reports, editorials and non-peer-reviewed literature were excluded from further analysis. As a result, 21 publications were included in this review.

Results

The available literature on nitroxoline's mechanism of action, pharmacokinetics, minimum inhibitory concentrations, in vitro activity and resistance rates strongly suggests that nitroxoline is a potent broad-spectrum antimicrobial agent. Moreover, clinical efficacy of the drug was analyzed - 2 articles proved high eradication rates in women with uncomplicated lower UTIs and 1 reported unsuccessful treatment in geriatric patients with lower complicated and uncomplicated UTIs. Finally, the present data on adverse effects indicate that nitroxoline is well-tolerated.

Conclusions

Nitroxoline is an obscure, yet potentially effective and safe antimicrobial agent in uncomplicated lower UTIs. Unfortunately, it is available only in a few countries. Nonetheless, nitroxoline can be useful in urological practice.

Nitroxoline resistance is associated with significant fitness loss and diminishes in vivo virulence of Escherichia coli

IMPORTANCE

Antimicrobial resistance (AMR) poses a global threat and requires the exploration of underestimated treatment options. Nitroxoline, an effective broad-spectrum antibiotic, does not suffer from high resistance rates in the clinics but surprisingly, it is not heavily used yet. Our findings provide compelling evidence that Nitroxoline resistance renders bacteria unable to cause an infection in vivo, thereby reinvigorating the potential of Nitroxoline in combating AMR.

Urinary pH and antibiotics, choose carefully. A systematic review

Uncomplicated urinary tract infection (UTI) is the most common bacterial infection in women. Since 1948, the relationship between urinary pH and antibiotics (ABs) has been established. We aimed to search for the best urinary pH for each family of antibiotics and to assess whether pH changes bacterial susceptibility to them. We included in vitro research and in vivo studies including one or more bacterial species and tested the effect of one or more ABs at different pH values. We also included randomized controlled clinical trials (RCTs) in uncomplicated UTI (EAU guidelines 2019 definition), choosing the ABs based on urinary pH or using an antibiotic plus urinary pH modifiers (L-methionine, vitamin C…) vs. an antibiotic and a placebo. Quadas-2 tool was used as a quality assessment of the studies and PRISMA set of items for systematic reviews. Two authors independently screened and evaluated the papers, while two additional authors individually repeated the search. A fifth researcher acted as an arbiter, and another author collaborated as a hospital pharmaceutical consultant. Alkaline-friendly antibiotics are most fluoroquinolones, aminoglycosides, trimethoprim. Acidic-friendly antibiotics are fosfomycin, tetracycline, nitrofurantoin and some β-lactams. We suggest performing urine cultures with antibiogram tests, in both acidic and alkaline media, to define the bacterial susceptibility profile. There is insufficient in vivo evidence to support whether choosing an antibiotic based on a patient's urinary pH or adding urinary pH modifiers will lead to a higher cure rate.

Cathepsin inhibitors nitroxoline and its derivatives inhibit SARS-CoV-2 infection

The severity of the SARS-CoV-2 pandemic and the recurring (re)emergence of viruses prompted the development of new therapeutic approaches that target viral and host factors crucial for viral infection. Among them, host peptidases cathepsins B and L have been described as essential enzymes during SARS-CoV-2 entry. In this study, we evaluated the effect of potent selective cathepsin inhibitors as antiviral agents. We demonstrated that selective cathepsin B inhibitors, such as the antimicrobial agent nitroxoline and its derivatives, impair SARS-CoV-2 infection in vitro. Antiviral activity observed at early stage of virus entry was cell-type dependent and correlated well with the intracellular content and enzymatic function of cathepsins B or L. Furthermore, tested inhibitors were effective against the ancestral SARS-CoV-2 D614 as well as against the more recent BA.1_4 (Omicron). Taken together, our results highlight the important role of host cysteine cathepsin B in SARS-CoV-2 virus entry and show that cathepsin-specific inhibitors, such as nitroxoline and its derivatives, could be used to treat COVID-19. Finally, these results also suggest that nitroxoline has potential to be further explored as repurposed drug in antiviral therapy.

Activity of the old antimicrobial nitroxoline against Mycobacterium abscessus complex isolates

OBJECTIVES

The old antimicrobial nitroxoline is approved to treat urinary tract infection (UTI) and is currently rediscovered for treatment of drug resistant pathogens. Mycobacteria of the Mycobacterium abscessus complex (MYABS) are rapid-growing nontuberculous mycobacteria that are associated with difficult to treat infections of the lungs in patients with pulmonary disorders such as cystic fibrosis. In this study we assessed the in vitro activity of nitroxoline against molecularly characterized drug-resistant MYABS isolates from clinical samples to address potential repurposing of nitroxoline in difficult-to-treat MYABS infection.

METHODS

The isolates originated from clinical samples collected between 2010 and 2019 at the University Hospital of Cologne, Germany (N=16; 10/16 M. abscessus Spp. abscessus, 4/16 M. abscessus Spp. massiliense, 2/16 M. abscessus Spp. bolletii). Nitroxoline activity was compared to standard antimicrobials recommended for treatment of MYABS infection. For drug susceptibility testing of nitroxoline and comparators broth microdilution was performed based on current Clinical and Laboratory Standards Institute (CLSI) guidelines.

RESULTS

Nitroxoline yielded a MIC₉₀ of 4 mg/L (range 2-4 mg/L), which is two twofold dilutions below the current EUCAST susceptibility breakpoint of ≤ 16 mg/L (limited to uncomplicated UTI and Escherichia coli). Resistance to other antimicrobials was common in our cohort (16/16 isolates resistant to ciprofloxacin, imipenem and doxycycline; 12/16 isolates resistant to tobramycin; 9/16 isolates resistant to cefoxitin; 7/16 isolates resistant to clarithromycin; 2/16 isolates resistant to amikacin).

CONCLUSION

Nitroxoline has a promising in vitro activity against drug-resistant MYABS isolates. Future studies should investigate this finding with macrophage and in vivo models.

Antimicrobial activity of clioquinol and nitroxoline: a scoping review

Clioquinol and nitroxoline, two drugs with numerous pharmacological properties fallen into disuse for many decades. The first was considered dangerous due to contraindications and the second mainly because was taken as ineffective, despite its known antibacterial activity. In the last decades, the advances in pharmaceutical chemistry, molecular biology, toxicology and genetics allowed to better understand the cellular action of these compounds, some toxicological issues and/or activity scopes. Thus, a new opportunity for these drugs to be considered as potential antimicrobial agents has arisen. This review contemplates the trajectory of clioquinol and nitroxoline from their emergence to the present day, emphasizing the new studies that indicate the possibility of reintroduction for specific cases.

In vitro Activity of Repurposed Nitroxoline Against Clinically Isolated Mycobacteria Including Multidrug-Resistant Mycobacterium tuberculosis

Antimicrobial treatment options for mycobacterial infections are limited due to intrinsic resistance and the emergence of acquired resistance in Mycobacterium tuberculosis. Isolates resisting first- and second line drugs are raising concerns about untreatable infections and make the development of new therapeutic strategies more pressing. Nitroxoline is an old oral antimicrobial that is currently repurposed for the treatment of urinary tract infection (UTI). In this study, we report the in vitro activity of nitroxoline against 18 clinical isolates of M. tuberculosis complex (MTBC) (M. tuberculosis N = 16, M. bovis BCG N = 1, M. bovis sp. bovis N = 1). Since nitroxoline achieves high concentrations in the urinary tract, we included all MTBC-isolates from urinary samples sent to our laboratory between 2008 and 2021 (University Hospital of Cologne, Germany). Isolates from other sources (N = 7/18) were added for higher sample size and for inclusion of drug-resistant M. tuberculosis isolates (N = 4/18). Based on our clinical routine the fluorescence-based liquid media system BACTEC MGIT 960 was used for susceptibility testing of nitroxoline and mainstay antitubercular drugs. Nitroxoline yielded a MIC₉₀ of 4 mg/L for MTBC. In all M. tuberculosis isolates nitroxoline MICs were at least two twofold dilutions below the current EUCAST susceptibility breakpoint of ≤16 mg/L (limited to E. coli and uncomplicated UTI). In vitro activity of nitroxoline can be considered excellent, even in multidrug-resistant isolates. Future studies with in vivo models should evaluate a potential role of nitroxoline in the treatment of tuberculosis in the era of drug resistance.

In Vitro Activity of Nitroxoline in Antifungal-Resistant Candida Species Isolated from the Urinary Tract

Infections by drug-resistant fungi are increasingly reported worldwide; however, only few novel antifungals are being developed. The old antimicrobial nitroxoline is currently repurposed for oral treatment of bacterial urinary tract infections (UTI). Previously, antifungal activity has been demonstrated and in contrast to many antifungals nitroxoline reaches high urinary concentrations. In this study, the activity of nitroxoline was assessed in vitro in a collection of yeasts from the German National Reference Centre for Invasive Fungal Infections. Susceptibility was determined by broth microdilution (BMD) and disk diffusion (DD). The collection comprised 45 Candida isolates originating from the urinary tract. MICs of amphotericin, anidulafungin and azoles were analyzed using EUCAST BMD. Among the collection isolates, resistance to antifungals was common, e.g., for fluconazole the MIC_50/90 was 16/>64 mg/L; in contrast MIC_50/90 of nitroxoline was 2/2 mg/L (MIC range 0.25-4 mg/L), which is at least two dilutions below the EUCAST breakpoint for uncomplicated UTI defined for E. coli (susceptible ≤ 16mg/L). Activity of nitroxoline was high irrespective of resistance to other agents. As BMD is labor-intensive, DD was investigated as an alternative method using three different agars. Nitroxoline disks produced large inhibition zones on all agars (≥19mm), but the correlation of MICs and zone diameters was low, with the highest correlation recorded for the CLSI recommended agar for antifungal DD (Pearson's r = -0,52). In conclusion, isolates of different Candida species are highly susceptible to nitroxoline, which could be a promising antimicrobial to treat candiduria caused by multidrug resistant yeasts.

OUP accepted manuscript

Background

With increasing resistance to common antibiotics the treatment of urinary tract infections has become challenging and alternative therapeutic options are needed. In the present study, we evaluate the activity of three older and less frequently used antibiotics against MDR Enterobacterales.

Methods

Susceptibility of mecillinam, temocillin and nitroxoline was assessed in Enterobacterales isolated from urinary specimens with elevated MICs of third-generation cephalosporins. Susceptibility was determined by the recommended reference MIC methods and additionally by disc diffusion. All isolates were characterized for common β-lactamases by phenotypic and molecular assays.

Results

In total 394 Enterobacterales were included. The most common resistance mechanisms were ESBLs (n = 273), AmpC (n = 132), carbapenemases [n = 12, including OXA-48-like (n = 8), VIM (n = 2), KPC (n = 1) and NDM (n = 1)] or others (n = 2). Resistance was observed in 59% of isolates to ceftazidime, in 41% to piperacillin/tazobactam and in 54% to ciprofloxacin. In comparison, resistance was less frequent against mecillinam (15%), temocillin (13%) or nitroxoline (2%). Mecillinam showed higher activity in Enterobacter spp., Escherichia coli and in OXA-48-like-producing isolates compared with temocillin, which was more active in Proteus mirabilis and in ESBL-producing isolates. Activity of nitroxoline was high against all isolates, including carbapenemase-producing isolates. Correlation between disc diffusion and MIC methods was good for mecillinam and moderate for temocillin and nitroxoline.

Conclusions

Mecillinam, temocillin and nitroxoline show good to excellent in vitro activity in MDR Enterobacterales. The activity of mecillinam and temocillin was higher in certain species and restricted depending on β-lactamase production while nitroxoline showed universally high activity irrespective of species or β-lactamase present.

Uropathogenic Escherichia coli Shows Antibiotic Tolerance and Growth Heterogeneity in an In Vitro Model of Intracellular Infection

Uropathogenic Escherichia coli (UPEC), the major causative agent of urinary tract infections, can invade different types of host cells. To compare the pharmacodynamic properties of antibiotics against intra- and extracellular UPEC, an in vitro model of intracellular infection was established in J774 mouse macrophages infected by the UPEC strain CFT073. We tested antibiotics commonly prescribed against urinary tract infections (gentamicin, ampicillin, nitrofurantoin, trimethoprim, sulfamethoxazole, and ciprofloxacin) and the investigational fluoroquinolone finafloxacin. The metabolic activity of individual bacteria was assessed by expressing the fluorescent reporter protein TIMERbac within CFT073. Concentration-response experiments revealed that all tested antibiotics were much less effective against intracellular bacteria than extracellular ones. Most antibiotics, except fluoroquinolones, were unable to reach a bactericidal effect intracellularly at clinically achievable concentrations. Ciprofloxacin and finafloxacin killed 99.9% of extracellular bacteria at concentrations around the MIC, while for intracellular bacteria, concentrations more than 100× over the MIC were required to achieve a bactericidal effect. Time-kill curves showed that finafloxacin was more rapidly bactericidal in acidic medium than at neutral pH, while the reverse observation was made for ciprofloxacin. Intracellularly, kill curves showed biphasic kinetics for both fluoroquinolones, suggesting the presence of drug-tolerant subpopulations. Flow cytometry analysis of TIMERbac fluorescence revealed a marked heterogeneity in intracellular growth of individual bacteria, suggesting that the presence of subpopulations reaching a state of metabolic dormancy was the main reason for increased antibiotic tolerance of intracellular UPEC.

Discovery and Validation of Nitroxoline as a Novel STAT3 Inhibitor in Drug-resistant Urothelial Bladder Cancer

Repeated cycles of first-line chemotherapy drugs such as doxorubicin (DOX) and cisplatin (CIS) trigger frequent chemoresistance in recurrent urothelial bladder cancer (UBC). Nitroxoline (NTX), an antibiotic to treat urinary tract infections, has been recently repurposed for cancer treatment. Here we aimed to investigate whether NTX suppresses drug-resistant UBC and its molecular mechanism. The drug-resistant cell lines T24/DOX and T24/CIS were established by continual exposure of parental cell line T24 to DOX and CIS, respectively. T24/DOX and T24/CIS cells were resistant to DOX and CIS, respectively, but they were sensitive to NTX time- and dose-dependently. Overexpressions of STAT3 and P-glycoprotein (P-gp) were identified in T24/DOX and T24/CIS, which could be reversed by NTX. Western blot revealed that NTX downregulated p-STAT3, c-Myc, Cyclin D1, CDK4, CDK6, Bcl-xL, Mcl-1, and Survivin, which were further confirmed by Stattic, a selective STAT3 inhibitor. In vivo, NTX exhibited the significant anti-tumor effect in T24/DOX and T24/CIS tumor-bearing mice. These results suggested that NTX-induced P-gp reversal, G0/G1 arrest, and apoptosis in drug-resistant UBC were mediated by inhibition of STAT3 signaling. Our findings repurpose NTX as a novel STAT3 inhibitor to induce P-gp reversal, G0/G1 arrest, and apoptosis in drug-resistant UBC.

Compared with Cotrimoxazole Nitroxoline Seems to Be a Better Option for the Treatment and Prophylaxis of Urinary Tract Infections Caused by Multidrug-Resistant Uropathogens: An In Vitro Study

The resistance of uropathogens to various antibiotics is increasing, but nitroxoline remains active in vitro against some relevant multidrug resistant uropathogenic bacteria. E. coli strains, which are among the most common uropathogens, are unanimously susceptible. Thus, nitroxoline is an option for the therapy of urinary tract infections caused by multiresistant bacteria. Since nitroxoline is active against bacteria in biofilms, it will also be effective in patients with indwelling catheters or foreign bodies in the urinary tract. Cotrimoxazole, on the other hand, which, in principle, can also act on bacteria in biofilms, is frequently inactive against multiresistant uropathogens. Based on phenotypic resistance data from a large number of urine isolates, structural characterisation of an MDR plasmid of a recent ST131 uropathogenic E. coli isolate, and publicly available genomic data of resistant enterobacteria, we show that nitroxoline could be used instead of cotrimoxazole for intervention against MDR uropathogens. Particularly in uropathogenic E. coli, but also in other enterobacterial uropathogens, the frequent parallel resistance to different antibiotics due to the accumulation of multiple antibiotic resistance determinants on mobile genetic elements argues for greater consideration of nitroxoline in the treatment of uncomplicated urinary tract infections.

Synthesis of Novel Nitroxoline Analogs with Potent Cathepsin B Exopeptidase Inhibitory Activity

Nitroxoline, a well-known antimicrobial agent, has been identified in several independent studies, and on different molecular targets, as a promising candidate to be repurposed for cancer treatment. One specific target of interest concerns cathepsin B, a lysosomal peptidase involved in the degradation of the extracellular matrix (ECM), leading to tumor invasion, metastasis and angiogenesis. However, dedicated optimization of the nitroxoline core is needed to actually deliver a nitroxoline-based antitumor drug candidate. Within that context, 34 novel nitroxoline analogs were synthesized and evaluated for their relative cathepsin B inhibitory activity, their antiproliferative properties and their antimicrobial activity. More than twenty analogs were shown to exert a similar or even slightly higher cathepsin B inhibitory activity compared to nitroxoline. The implemented modifications of the nitroxoline scaffold and the resulting SAR information can form an eligible basis for further optimization toward more potent cathepsin B inhibitors in the quest for a clinical nitroxoline-based antitumor agent.

Antimicrobial pharmacokinetics and preclinical in vitro models to support optimized treatment approaches for uncomplicated lower urinary tract infections

INTRODUCTION

Urinary tract infections (UTIs) are extremely common. Millions of people, particularly healthy women, are affected worldwide every year. One-in-two women will have a recurrence within 12-months of an initial UTI. Inadequate treatment risks worsening infection leading to acute pyelonephritis, bacteremia and sepsis. In an era of increasing antimicrobial resistance, it is critical to provide optimized antimicrobial treatment.

AREAS COVERED

Literature was searched using PubMed and Google Scholar (up to 06/2020), examining the etiology, diagnosis and oral antimicrobial therapy for uncomplicated UTIs, with emphasis on urinary antimicrobial pharmacokinetics (PK) and the application of dynamic in vitro models for the pharmacodynamic (PD) profiling of pathogen response.

EXPERT OPINION

The majority of antimicrobial agents included in international guidelines were developed decades ago without well-described dose-response relationships. Microbiology laboratories still apply standard diagnostic methodology that has essentially remained unchanged for decades. Furthermore, it is uncertain how relevant standard in vitro susceptibility is for predicting antimicrobial efficacy in urine. In order to optimize UTI treatments, clinicians must exploit the urine-specific PK of antimicrobial agents. Dynamic in vitro models are valuable tools to examine the PK/PD and urodynamic variables associated with UTIs, while informing uropathogen susceptibility reporting, optimized dosing schedules, clinical trials and treatment guidelines.

Analogs of nitrofuran antibiotics are potent GroEL/ES inhibitor pro-drugs

In two previous studies, we identified compound 1 as a moderate GroEL/ES inhibitor with weak to moderate antibacterial activity against Gram-positive and Gram-negative bacteria including Bacillus subtilis, methicillin-resistant Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, and SM101 Escherichia coli (which has a compromised lipopolysaccharide biosynthetic pathway making bacteria more permeable to drugs). Extending from those studies, we developed two series of analogs with key substructures resembling those of known antibacterials, nitroxoline (hydroxyquinoline moiety) and nifuroxazide/nitrofurantoin (bis-cyclic-N-acylhydrazone scaffolds). Through biochemical and cell-based assays, we identified potent GroEL/ES inhibitors that selectively blocked E. faecium, S. aureus, and E. coli proliferation with low cytotoxicity to human colon and intestine cells in vitro. Initially, only the hydroxyquinoline-bearing analogs were found to be potent inhibitors in our GroEL/ES-mediated substrate refolding assays; however, subsequent testing in the presence of an E. coli nitroreductase (NfsB) in situ indicated that metabolites of the nitrofuran-bearing analogs were potent GroEL/ES inhibitor pro-drugs. Consequently, this study has identified a new target of nitrofuran-containing drugs, and is the first reported instance of such a unique class of GroEL/ES chaperonin inhibitors. The intriguing results presented herein provide impetus for expanded studies to validate inhibitor mechanisms and optimize this antibacterial class using the respective GroEL/ES chaperonin systems and nitroreductases from E. coli and the ESKAPE bacteria.

Discovering Cross-Reactivity in Urine Drug Screening Immunoassays through Large-Scale Analysis of Electronic Health Records

BACKGROUND

Exposure to drugs of abuse is frequently assessed using urine drug screening (UDS) immunoassays. Although fast and relatively inexpensive, UDS assays often cross-react with unrelated compounds, which can lead to false-positive results and impair patient care. The current process of identifying cross-reactivity relies largely on case reports, making it sporadic and inefficient, and rendering knowledge of cross-reactivity incomplete. Here, we present a systematic approach to discover cross-reactive substances using data from electronic health records (EHRs).

METHODS

Using our institution's EHR data, we assembled a data set of 698651 UDS results across 10 assays and linked each UDS result to the corresponding individual's previous medication exposures. We hypothesized that exposure to a cross-reactive ingredient would increase the odds of a false-positive screen. For 2201 assay-ingredient pairs, we quantified potential cross-reactivity as an odds ratio from logistic regression. We then evaluated cross-reactivity experimentally by spiking the ingredient or its metabolite into drug-free urine and testing the spiked samples on each assay.

RESULTS

Our approach recovered multiple known cross-reactivities. After accounting for concurrent exposures to multiple ingredients, we selected 18 compounds (13 parent drugs and 5 metabolites) to evaluate experimentally. We validated 12 of 13 tested assay-ingredient pairs expected to show cross-reactivity by our analysis, discovering previously unknown cross-reactivities affecting assays for amphetamines, buprenorphine, cannabinoids, and methadone.

CONCLUSIONS

Our findings can help laboratorians and providers interpret presumptive positive UDS results. Our data-driven approach can serve as a model for high-throughput discovery of substances that interfere with laboratory tests.

Identification of plicamycin, TG02, panobinostat, lestaurtinib, and GDC-0084 as promising compounds for the treatment of central nervous system infections caused by the free-living amebae Naegleria, Acanthamoeba and Balamuthia

The free-living amebae Naegleria, Acanthamoeba, and Balamuthia cause rare but life-threatening infections. All three parasites can cause meningoencephalitis. Acanthamoeba can also cause chronic keratitis and both Balamuthia and Acanthamoeba can cause skin and systemic infections. There are minimal drug development pipelines for these pathogens despite a lack of available treatment regimens and high fatality rates. To identify anti-amebic drugs, we screened 159 compounds from a high-value repurposed library against trophozoites of the three amebae. Our efforts identified 38 compounds with activity against at least one ameba. Multiple drugs that bind the ATP-binding pocket of mTOR and PI3K are active, highlighting these compounds as important inhibitors of these parasites. Importantly, 24 active compounds have progressed at least to phase II clinical studies and overall 15 compounds were active against all three amebae. Based on central nervous system (CNS) penetration or exceptional potency against one amebic species, we identified sixteen priority compounds for the treatment of meningoencephalitis caused by these pathogens. The top five compounds are (i) plicamycin, active against all three free-living amebae and previously U.S. Food and Drug Administration (FDA) approved, (ii) TG02, active against all three amebae, (iii and iv) FDA-approved panobinostat and FDA orphan drug lestaurtinib, both highly potent against Naegleria, and (v) GDC-0084, a CNS penetrant mTOR inhibitor, active against at least two of the three amebae. These results set the stage for further investigation of these clinically advanced compounds for treatment of infections caused by the free-living amebae, including treatment of the highly fatal meningoencephalitis.

Detection of microbial colonization of the urinary tract of patients prior to secondary ureterorenoscopy is highly variable between different types of assessment: results of a prospective observational study

This study compares the findings of different detection methods for microorganisms in patients with ureteral stents undergoing secondary ureterorenoscopy including the use of a novel validated examination pipeline for biofilms on ureteral stents. Of the included 94 patients, 21.3% showed bacteriuria in preoperative urine cultures. Intraoperative urine culture showed bacteriuria in four (4.3%) of the patients. Stent biofilm cultures were positive in 12.9% and qPCR detected bacterial DNA in 18.1%. The findings of the different examinations were poorly correlated with each other. Detection of microorganisms in the urinary tract of patients with indwelling ureteral stents is highly dependent on timing (i.e. pre- vs intraoperative) and method of assessment. Preoperative routine urine cultures are not predictive for intraoperative urine- and stent culture. These results cast doubt on the clinical relevance of enterococcal species, staphylococci, and streptococci if identified preoperatively prior to stent removal. The timing of oral preoperative antibiotic prophylaxis might need to be reconsidered.

Mutations that increase expression of the EmrAB-TolC efflux pump confer increased resistance to nitroxoline in Escherichia coli

Objectives

To determine the mechanism of resistance to the antibiotic nitroxoline in Escherichia coli.

Methods

Spontaneous nitroxoline-resistant mutants were selected at different concentrations of nitroxoline. WGS and strain reconstruction were used to define the genetic basis for the resistance. The mechanistic basis of resistance was determined by quantitative PCR (qPCR) and by overexpression of target genes. Fitness costs of the resistance mutations and cross-resistance to other antibiotics were also determined.

Results

Mutations in the transcriptional repressor emrR conferred low-level resistance to nitroxoline [nitroxoline MIC (MICNOX) = 16 mg/L] by increasing the expression of the emrA and emrB genes of the EmrAB-TolC efflux pump. These resistant mutants showed no fitness reduction and displayed cross-resistance to nalidixic acid. Second-step mutants with higher-level resistance (MICNOX = 32–64 mg/L) had mutations in the emrR gene, together with either a 50 kb amplification, a mutation in the gene marA, or an IS upstream of the lon gene. The latter mutations resulted in higher-level nitroxoline resistance due to increased expression of the tolC gene, which was confirmed by overexpressing tolC from an inducible plasmid in a low-level resistance mutant. Furthermore, the emrR mutations conferred a small increase in resistance to nitrofurantoin only when combined with an nfsAB double-knockout mutation. However, nitrofurantoin-resistant nfsAB mutants showed no cross-resistance to nitroxoline.

Conclusions

Mutations in different genes causing increased expression of the EmrAB-TolC pump lead to an increased resistance to nitroxoline. The structurally similar antibiotics nitroxoline and nitrofurantoin appear to have different modes of action and resistance mechanisms.

Review of the pharmacokinetic properties of nitrofurantoin and nitroxoline

Nitrofurantoin and nitroxoline are oral antibiotics for the treatment or prophylaxis of acute urinary tract infections. New interest in both these drugs is increasing because of the emergence of resistance to other antibiotics, but knowledge of their pharmacokinetics (PK) is lacking since they were developed before the advent of standardized research for drug approval. The aims of this review were to (i) summarize the PK data reported in the literature and (ii) to identify PK knowledge gaps. The current body of PK knowledge of both drugs appears to be poor and mainly based on old studies. Nitrofurantoin PK values were obtained from studies using many variables, e.g. formulations, crystal sizes and analytical methods, resulting in high interindividual variability in PK parameters and no uniform PK profile. Clinical experience and PK data for nitroxoline are even more limited since the drug is registered in only Germany and a few (Eastern European) countries. Clinical studies in relevant patient populations are needed with commercially available nitrofurantoin and nitroxoline formulations at approved dosing regimens to more fully characterize their PK profiles, and to investigate the influence of patient characteristics on these profiles in order to optimize efficacy and avoid toxicity and emergence of resistance. Only with this updated knowledge and efficacy data from well-structured trials can both drugs maintain their antimicrobial activity against uropathogens.

Nitroxoline: a potent antimicrobial agent against multidrug resistant Enterobacteriaceae

Antimicrobial resistance has become a prime global concern. An ability of the microbes to produce enzymes to destroy antimicrobial drugs is one of the well-known mechanisms underlying the resistance. 8-Hydroxyquinoline (8HQ) and derivatives were reported to exert diverse biological effects such as antimicrobial, antioxidant and antineurodegenerative activities. Herein, 8HQ (1), nitroxoline (NQ, 2) and 7-Br-8HQ (3) were investigated for antimicrobial activity against Enterobacteriaceae including extended spectrum β-lactamase (ESBL)-producing and carbapenemase-producing strains as well as the effect of metal ions. These compounds (1-3) displayed the great antimicrobial activity against fifty-eight bacterial isolates of Escherichiacoli, Providenciarettgeri and Klebsiellapneumoniae, in which NQ (2) exerted the highest antimicrobial activity with a MIC₅₀ of 42.04 μM (8 µg/mL) and MBC₅₀ of 168.28 μM (32 µg/mL). The MIC values of NQ (2) and 7-Br-8HQ (3) were significantly increased in the presence of Cu²⁺ and Fe³⁺. This finding reveals that NQ could be an effective compound to be further developed as an antimicrobial agent for combating Enterobacteriaceae infections.

Urinary antibacterial activity of fosfomycin and nitrofurantoin at registered dosages in healthy volunteers

Given emerging uropathogen resistance to more recent antibiotics, old antibiotics used for uncomplicated urinary tract infection (UTI) warrant re-examination. In this study, the urinary antibacterial activities of fosfomycin and nitrofurantoin were investigated by determining the urinary inhibitory titre and urinary bactericidal titre against uropathogens in urine samples from female volunteers following administration of single-dose fosfomycin (3 g) or nitrofurantoin (50 mg q6h or 100 mg q8h). Urine samples were collected over 48 h (fosfomycin) or 6 or 8 h (nitrofurantoin), with drug levels quantified with every void. Fosfomycin concentrations ranged from <0.75 mg/L [lower limit of quantification (LLOQ)] to 5729.9 mg/L and nitrofurantoin concentrations ranged from <4 mg/L (LLOQ) to 176.3 mg/L (50 mg q6h) or 209.4 mg/L (100 mg q8h). There was discrepancy in the response to fosfomycin between Escherichia coli and Klebsiella pneumoniae, with fosfomycin displaying strong bactericidal activity for 48 h against E. coli but moderate bactericidal activity for 18 h against K. pneumoniae. This effect was not related to the strain's baseline minimum inhibitory concentration but rather to the presence of a resistant subpopulation. Maximum titres of nitrofurantoin were obtained during the first 2 h, but no antibacterial effect was found in most samples regardless of the dose. In the rare samples in which antibacterial activity was detectable, titres were comparable for both species tested. These findings confirm doubts regarding fosfomycin administration in UTIs caused by K. pneumoniae and reveal a discrepancy between nitrofurantoin's measurable ex vivo activity and its clinical effect over multiple dosing intervals.

In vitro activity of mecillinam and nitroxoline against Neisseria gonorrhoeae - re-purposing old antibiotics in the multi-drug resistance era

In 2018, the European Centre for Disease Prevention and Control reported the first cases of extensively drug-resistant Neisseria gonorrhoeae infections in Europe. Seeking new options for antimicrobial therapy we investigated the susceptibility of N. gonorrhoeae to nitroxoline (NIT) and mecillinam (MCM), both of which are currently only indicated to treat uncomplicated urinary tract infections. Clinical N. gonorrhoeae isolates with non-susceptibility to penicillin from two German medical centres were included (n =27). Most isolates were also non-susceptible to a range of other anti-gonococcal antimicrobials (cefotaxime, ciprofloxacin, azithromycin, tetracycline). All isolates were further characterized by multi-locus sequence typing. MICs of penicillin and cefotaxime were determined by agar gradient diffusion. Production of penicillinase was tested by cefinase disk test. Susceptibility of MCM was investigated by agar dilution, NIT by agar dilution and disk diffusion. Penicillin MICs ranged from 0.125 to 64 mg l^-1 and MICs of cefotaxime ranged from < 0.016 to 1 mg l^-1 . Five isolates were penicillinase-producers. MICs of MCM ranged from 16 to > 128 mg l^-1 whereas MICs of NIT ranged from 0.125 to 2 mg l^-1 . NIT disk diffusion (median zone diameter 32 mm) correlated well with results from agar dilution. We demonstrated excellent in vitro activity of NIT against clinical N. gonorrhoeae isolates with non-susceptibility to standard anti-gonococcal antibiotics. MCM activity was unsatisfactory. Correlation of agar dilution and disk diffusion in NIT susceptibility testing is an important aspect with potential clinical implications.

Optimizing dosing of nitrofurantoin from a PK/PD point of view: What do we need to know?

Nitrofurantoin is an old antibiotic and an important first-line oral antibiotic for the treatment of uncomplicated urinary tract infections. However despite its long term use for over 60 years, little information is available with respect to its dose justification and this may be the reason of highly variable recommended doses and dosing schedules. Furthermore, nitrofurantoin is not a uniform product -crystal sizes of nitrofurantoin, and therefore pharmacokinetic properties, differ significantly by product. Moreover, pharmacokinetic profiling of some products is even lacking, or difficult to interpret because of its unstable chemical properties. Pharmacokinetic and pharmacodynamic data is now slowly becoming available. This review provides an overview of nitrofurantoins antibacterial, pharmacokinetic and pharmacodynamic properties. This shows that a clear rationale of current dosing regimens is scanty.

Repositioning of 8-hydroxyquinoline derivatives as a new promising candidate for combating multidrug resistant Neisseria gonorrhoeae

The multidrug resistance of Neisseria gonorrhoeae becomes a public health problem worldwide, especially the strain H041 that showed the decrease susceptibility to ceftriaxone which is the last resort for gonorrhea treatment. Therefore, the simultaneous discovery and development of a new compound to fight this pathogen is urgently required. In this study, 8-hydroxyquinoline (8HQ) and derivatives were evaluated for their antimicrobial activities against the gonococcal pathogen using spectinomycin as the reference drug. The results showed that 8HQ derivatives gave an excellent antimicrobial potency. Particularly, the dihalogenated 8HQ (iodoquinol, clioquinol and 5,7-diCl-8HQ) exerted the high activity with MIC range of 0.08-0.15 μM, 0.10-0.20 μM and 0.28-0.56 µM, respectively, compared with the reference drug (MIC = 16 μg/mL or 48.14 μM). Moreover, these compounds were also shown to be non-cytotoxic/very high safety index. The findings reveal that these three compounds could be further developed as a new antimicrobial agent for fighting the gonorrheal disease.

Empirical treatment of lower urinary tract infections in the face of spreading multidrug resistance: in vitro study on the effectiveness of nitroxoline

The spread of antimicrobial resistance challenges the empirical treatment of urinary tract infections (UTIs). Among others, nitrofurantoin is recommended for first-line treatment, but acceptance among clinicians is limited due to chronic nitrofurantoin-induced lung toxicity and insufficient coverage of Enterobacteriaceae other than Escherichia coli. Nitroxoline appears to be an alternative to nitrofurantoin owing to its favourable safety profile, however data on its current in vitro susceptibility are sparse. In this study, susceptibility to nitroxoline was tested against 3012 urinary clinical isolates (including multidrug-resistant bacteria and Candida spp.) by disk diffusion test and/or broth microdilution. At least 91% of all Gram-negatives (n = 2000), Gram-positives (n = 403) and yeasts (n = 132) had inhibition zone diameters for nitroxoline ≥18 mm. Except for Pseudomonas aeruginosa, nitroxoline MIC₉₀ values were ≤16 mg/L and were 2- to >16-fold lower compared with nitrofurantoin. In extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and methicillin-resistant Staphylococcus aureus (MRSA), MIC₉₀ values of nitroxoline were two-fold higher compared with non-ESBL-producing enterobacteria and methicillin-susceptible S. aureus (MSSA). The in vitro efficacies of nitroxoline and nitrofurantoin against ATCC strains of E. coli, Enterococcus faecalis and Proteus mirabilis were compared by time-kill curves in Mueller-Hinton broth and artificial urine. Nitroxoline was non-inferior against E. coli, P. mirabilis and E. faecalis in artificial urine. In conclusion, nitroxoline showed a broad antimicrobial spectrum, with inhibition zone diameters and MICs of nitroxoline well below the EUCAST breakpoint for E. coli for most organisms, and thus may also be a target for therapy of uncomplicated UTIs.

[Nitroxoline - an option for the antibiotic treatment of urinary tract infections]

BACKGROUND

Resistance of uropathogenic bacteria against the common antibiotics is considerable-especially in the elderly.

OBJECTIVES

In Germany nitroxoline is licensed for the treatment of acute urinary tract infections and for prophylaxis of recurrent infections. What is the actual resistance pattern of uropathogenic bacteria?

MATERIALS AND METHODS

The in vitro susceptibility of 477 uropathogenic bacteria from patients in 2015 was determined by means of the agar diffusion method.

RESULTS

Obviously, this agent is still active against the vast majority of uropathogenic bacteria and in particular against strains of Escherichia coli (E. coli). Pseudomonas aeruginosa and enterococci are not really within the spectrum of nitroxoline. One has to keep in mind, however, that even among E. coli and other enterobacteriaceae there are single resistant isolates. This applies in particular to problem strains resistant to many other antibiotics.

DISCUSSION

Nitroxoline is a reasonable alternative and a promising option for calculated treatment of urinary tract infections-especially of the elderly, although this drug is not recommended in the current guideline. Laboratory testing of clinical isolates should be requested-at least when treatment fails.

[Candiduria! What now? : Therapy of urinary tract infections with Candida]

BACKGROUND

Yeasts are found in urine specimens relatively often, especially in the elderly and patients under treatment with broad spectrum antibiotics, i. e. especially in intensive care unit (ICU) patients. In some cases, the number of pathogens is very high, i. e. >10⁵/ml. The clinical relevance of detecting Candida in urine is difficult to assess. In the German S3 guidelines it is apodictically stated that an ascending infection of the urinary tract by yeasts does not occur but this may undoubtedly happen in certain instances in patients at risk, for example in the elderly, in diabetic persons and in the case of foreign bodies in the urinary tract. A hematogenous spread of yeasts can lead to pyelonephritis, which accompanies candiduria. In rare cases this can be induced by prostatitis and epididymitis. Therapy is indicated in all cases when a urological manipulation is planned, particularly those with injury to the mucosal barrier, in order to prevent an intraoperative spread of pathogens.

AIM

The antimicrobial agents suitable for therapy of candiduria are limited, namely flucytosine, amphotericin B, which is also used for irrigation and fluconazole.

MATERIAL AND METHODS

The in vitro effect of nitroxoline on 100 isolates of yeasts from urine was tested by an agar diffusion test.

RESULTS

Nitroxoline exerted a good activity against all yeast isolates.

DISCUSSION

The antibiotic nitroxoline has a good antifungal activity. It achieves high concentrations in urine and in addition, it is effective at low pH as well as against pathogens in biofilms, which most antimycotics cannot achieve. Hence, nitroxoline is suitable for termination of candiduria. Foreign bodies in the urinary tract, on which biofilms are formed, should be removed whenever possible.

[Community acquired urinary tract infections - association with risk factors : Changes in causative organisms and resistance over time]

BACKGROUND

Published studies on community-acquired urinary tract infections (UTI) often do not link microbiological findings with clinical risk factors and patient data.

MATERIALS AND METHODS

We retrospectively correlated clinical findings of all patients with UTI of a urological outpatient clinic with the respective microbiological analysis of their urine samples over 2 periods of time: (A: 2005-2006 and B: 2011-2012). Patients were stratified to the following risk groups: uncomplicated cystitis, diabetes mellitus type 2, nursing home resident, prostatitis/epidydimitis, permanent catheter.

RESULTS

The incidence of Escherichia coli (p < 0.001) and proteus (p < 0.001) significantly decreased from period A to B, while enterococci (p = 0.003) and staphylococci (p < 0.001) significantly increased. Antibiotic sensitivity to fosfomycin (p < 0.001), doxycycline (p < 0.001), nitrofurantoin (p < 0.001), and nitroxoline increased (p < 0. 001) and sensitivity to amoxicillin (p < 0.001) and gentamicin decreased (p < 0.001). Patients with a permanent catheter had significantly poorer sensitivity rates (50% and less) for almost all antibiotics tested compared to the overall group. The risk of a UTI with 3MRGN or MRSA bacteria was significantly higher for catheter carriers and nursing home residents.

CONCLUSIONS

Empiric antibiotic first-line therapy with nitrofurantoin and fosfomycin for uncomplicated community acquired UTIs are well indicated in conformity with guidelines. The accumulation of multiresistant pathogens in patients with a permanent bladder catheter requires restrictive use of any permanent catheter drainage.

Lab-on-a-Chip-Surface Enhanced Raman Scattering Combined with the Standard Addition Method: Toward the Quantification of Nitroxoline in Spiked Human Urine Samples

The emergence of antibacterial resistance and the development of new drugs lead to a continuous change of guidelines for medical treatments. Hence, new analytical tools are required for the detection of drugs in biological fluids. In this study, the first surface enhanced Raman scattering (SERS) detection of nitroxoline (NTX) in purified water and in spiked human urine samples is reported. Insights concerning the nature of the molecule-metal interaction and its influence on the overall SERS signal are provided. Furthermore, three randomly collected urine samples originating from a healthy volunteer were spiked to assess the limit of detection (LOD), the limit of quantification (LOQ), and the linear dynamic range of the lab-on-a-chip SERS (LoC-SERS) method for NTX detection in human urine. The LOD is ∼3 μM (0.57 mg/L), LOQ ∼ 6.5 μM (1.23 mg/L) while the linear range is between 4.28 and 42.8 μM (0.81-8.13 mg/L). This covers the minimum inhibitory concentration (MIC) values of the most commonly encountered uropathogens. Finally, seven clinical samples having an "unknown" NTX concentration were simulated. The LoC-SERS technique combined with the standard addition method and statistical data analysis provided a good prediction of the unknown concentrations. Additionally, it is also demonstrated that the predictions carried out by multicurve resolution alternating least-squares (MCR-ALS) algorithm provides reliable results, and it is preferred to a univariate statistical approach.

Effect of 8-hydroxyquinoline and derivatives on human neuroblastoma SH-SY5Y cells under high glucose

8-Hydroxyquinoline and derivatives exhibit multifunctional properties, including antioxidant, antineurodegenerative, anticancer, anti-inflammatory and antidiabetic activities. In biological systems, elevation of intracellular calcium can cause calpain activation, leading to cell death. Here, the effect of 8-hydroxyquinoline and derivatives (5-chloro-7-iodo-8-hydroxyquinoline or clioquinol and 8-hydroxy-5-nitroquinoline or nitroxoline) on calpain-dependent (calpain-calpastatin) pathways in human neuroblastoma (SH-SY5Y) cells was investigated. 8-Hydroxyquinoline and derivatives ameliorated high glucose toxicity in SH-SY5Y cells. The investigated compounds, particularly clioquinol, attenuated the increased expression of calpain, even under high-glucose conditions. 8-Hydroxyquinoline and derivatives thus adversely affected the promotion of neuronal cell death by high glucose via the calpain-calpastatin signaling pathways. These findings support the beneficial effects of 8-hydroxyquinolines for further therapeutic development.

Preclinical pharmacodynamic evaluation of antibiotic nitroxoline for anticancer drug repurposing

The established urinary antibiotic nitroxoline has recently regained considerable attention, due to its potent activities in inhibiting angiogenesis, inducing apoptosis and blocking cancer cell invasion. These features make nitroxoline an excellent candidate for anticancer drug repurposing. To rapidly advance nitroxoline repurposing into clinical trials, the present study performed systemic preclinical pharmacodynamic evaluation of its anticancer activity, including a methyl thiazolyl tetrazolium assay in vitro and an orthotopic urological tumor assay in vivo. The current study determined that nitroxoline exhibits dose-dependent anti-cancer activity in vitro and in urological tumor orthotopic mouse models. In addition, it was demonstrated that the routine nitroxoline administration regimen used for urinary tract infections was effective and sufficient for urological cancer treatment, and 2 to 4-fold higher doses resulted in obvious enhancement of anticancer efficacy without corresponding increases in toxicity. Furthermore, nitroxoline sulfate, one of the most common metabolites of nitroxoline in the urine, effectively inhibited cancer cell proliferation. This finding increases the feasibility of nitroxoline repurposing for urological cancer treatment. Due to the excellent anticancer activity demonstrated in the present study, and its well-known safety profile and pharmacokinetic properties, nitroxoline has been approved to enter into a phase II clinical trial in China for non-muscle invasive bladder cancer treatment (registration no. CTR20131716).

The Transcriptome Sequence of Dientamoeba fragilis Offers New Biological Insights on its Metabolism, Kinome, Degradome and Potential Mechanisms of Pathogenicity

Dientamoeba fragilis is a human bowel parasite with a worldwide distribution. Dientamoeba was once described as a rare and harmless commensal though recent reports suggest it is common and potentially pathogenic. Molecular data on Dientamoeba is scarce which limits our understanding of this parasite. To address this, sequencing of the Dientamoeba transcriptome was performed. Messenger RNA was extracted from cultured Dientamoeba trophozoites originating from clinical stool specimens, and sequenced using Roche GS FLX and Illumina HiSeq technologies. In total 6,595 Dientamoeba transcripts were identified. These sequences were analysed using the BLAST2GO software suite and via BLAST comparisons to sequences available from TrichDB, GenBank, MEROPS and kinase.com. Several novel KEGG pathway maps were generated and gene ontology analysis was also performed. These results are thoroughly discussed guided by knowledge available for other related protozoa. Attention is paid to the novel biological insights afforded by this data including peptidases and kinases of Dientamoeba, as well as its metabolism, novel chemotherapeutics and possible mechanisms of pathogenicity. Currently, this work represents the largest contribution to our understanding of Dientamoeba molecular biology and also represents a major contribution to our understanding of the trichomonads generally, many of which are important pathogens of humans and animals.

Review of the literature and individual patients' data meta-analysis on efficacy and tolerance of nitroxoline in the treatment of uncomplicated urinary tract infections

BACKGROUND

Nitroxoline, a hydroxychinoline derivate, has been used for many years to treat urinary tract infections (UTI). Many uncontrolled, but only few controlled clinical studies have been published. Four so far unpublished, controlled clinical studies were meta-analysed.

METHODS

A narrative literature review was performed. In addition the individual patient data (IPD) of 466 females with uncomplicated UTI of four prospective, single blind, randomized, clinical studies with similar protocols using nitroxoline (250 mg tid) versus cotrimoxazole (960 mg bid) or norfloxacin (400 mg bid) as controls for 5 days (sporadic UTI) or 10 days (recurrent UTI) were meta-analysed. The primary aim was eradication of bacteriuria 7-13 days after end of therapy (test of cure). Clinical efficacy was determined by elimination of symptoms and safety by adverse events and laboratory tests.

RESULTS

Reviewing a total of 26 uncontrolled, 2 controlled and one postmarketing studies including more than 11,000 patients, good efficacy and safety of nitroxoline could be confirmed. In the four unpublished controlled studies a total of 234 patients were treated orally with nitroxoline and 232 with controls. The safety of nitroxoline was very good and comparable to the controls (adverse events 9.4% vs 7.8%; p = 0.360). In the mMITT set (at least one outcome result), in the PP set (test of cure outcome) and in the modified PP set (missing test of cure rated failure) more than 90% of the patients showed eradication of bacteriuria with nitroxoline, which also met statistical non-inferiority compared to the controls (10% non-inferiority margin) in all three evaluation sets. The clinical efficacy was similar between the two treatment groups.

CONCLUSION

The IPD meta-analysis using objective parameters (elimination of bacteriuria) demonstrated equivalent efficacy (non-inferiority) of nitroxoline with the controls tested (cotrimoxazole, norfloxacin) in the treatment of uncomplicated UTI. Considering the good safety and efficacy of nitroxoline as also shown in many uncontrolled and observational studies and the world wide increase of resistance of uropathogens against cotrimoxazole and fluoroquinolones, but not against nitroxoline within the last 20 years, nitroxoline should be reconsidered as one of the first line antibiotics for the treatment of uncomplicated UTI.

Discovery of quinoline small molecules with potent dispersal activity against methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis biofilms using a scaffold hopping strategy

Staphylococcus aureus and Staphylococcus epidermidis are recognized as the most frequent cause of biofilm-associated nosocomial and indwelling medical device infections. Biofilm-associated infections are known to be highly resistant to our current arsenal of clinically used antibiotics and antibacterial agents. To exacerbate this problem, no therapeutic option exists that targets biofilm-dependent machinery critical to Staphylococcal biofilm formation and maintenance. Here, we describe the discovery of a series of quinoline small molecules that demonstrate potent biofilm dispersal activity against methicillin-resistant S. aureus and S. epidermidis using a scaffold hopping strategy. This interesting class of quinolines also has select synthetic analogues that demonstrate potent antibacterial activity and biofilm inhibition against S. aureus and S. epidermidis.