DiagnoSwiss (Switzerland)

Abstract Background Zosurabalpin (RG6006) is the first representative of a novel class of tethered macrocyclic peptide antibiotics active against Acinetobacter spp., including carbapenem-resistant Acinetobacter baumannii-calcoaceticus complex (ABC) organisms. In this study, the susceptibility testing of zosurabalpin was carried out against a panel of 150 randomly selected Acinetobacter spp. isolates (100 A. baumannii & 50 non-A. baumannii) representing 11 sites in China and a broad susceptibility profile (65% of which were multi-drug resistant [MDR]) collected in 2021. Methods MICs were performed using the Clinical Laboratory Standards Institute (CLSI) broth dilution method cation-adjusted Mueller Hinton broth (CA-MHB) supplemented with either 20% of human serum (HS) or 20% of horse serum (HoS). For a fraction of isolates (10-25%), MIC determination for zosurabalpin is affected by aberrant readings (trailing, multiple skipped wells) in CA-MHB. This effect complicates routine susceptibility testing. Supplementation of CAMHB with serum allows accurate MIC determinations without any major effects on the MIC distribution. Results Summary data from the study are shown in Table 1. Zosurabalpin was active against all Acinetobacter spp., with an MIC50/90 of 0.12/0.5 μg/mL and 0.25/1 μg/mL in CA-MHB supplemented with HoS and HS, respectively (MIC range of 0.015/0.03 to 8 μg/mL). Against ABC isolates (n=133), the MIC50/90 for zosurabalpin was 0.12/0.25 μg/mL and 0.25/0.5 μg/mL, in HoS and HS, respectively (MIC range of 0.015/0.03 to 1 μg/mL). A similar activity was observed against carbapenem-resistant ABC isolates. Conclusion In addition to the potent activity observed against isolates from USA and Europe, zosurabalpin exhibited potent in vitro antibacterial activity against Acinetobacter clinical isolates circulating in China. These data support the continued clinical development of zosurabalpin for infections caused by ABC isolates, including difficult to treat carbapenem-resistant isolates. Disclosures Stephen Hawser, PhD, Allecra: study funding|Innoviva Specialty Therapeutics, Inc.: Honoraria|Roche: Honoraria|Roche: This project has been funded by BARDA (HHSO100201600038C). Nimmi Kothari, PhD, Allecra: Allecra (study funding)|Innoviva Specialty Therapeutics, Inc.: Honoraria|Roche: Honoraria|Roche: This project has been funded by BARDA (HHSO100201600038C). Thomas Valmont, BS, Roche: Honoraria|Roche: This project has been funded by BARDA (HHSO100201600038C). Séverine Louvel, PhD, F. Hoffmann-La Roche Ltd: employee of the company Claudia Zampaloni, n/a, F. Hoffmann-La Roche Ltd.: Full time employee of Roche

BackgroundMecillinam is a unique amidinopenicillin antibiotic, being the first and the only compound in its class. In contrast to other beta-lactams, it has a unique mechanism of action whereby it exerts its antibacterial activity through binding to penicillin binding protein 2. Pivmecillinam is the oral-prodrug of mecillinam and recommended as a first line therapy in the IDSA guidelines for uncomplicated urinary tract infections (uUTI), despite not yet being available in the USA. To support the clinical development of mecillinam and pivmecillinam in the USA for the treatment of both complicated UTI and uUTI this study investigated the activity of mecillinam against Enterobacterales isolates from the USA during 2018.MethodsA total of 1,090 isolates from urinary tract infections from patients in the USA were tested. Activity of antibiotics was tested by CLSI methodology and susceptibility interpreted according to CLSI guidelines.ResultsSusceptibility and activity of each antibiotic are shown in the Table. Mecillinam MIC50 and MIC90 were 0.25 and 4 µg/mL, respectively and 94.5% of isolates were susceptible. Fosfomycin MIC50 and MIC90 were 2 and 32 µg/mL, respectively and 95.7% of isolates were susceptible. The other four comparator antibiotics showed MIC90 values >8 µg/mL and a 70.5 – 79.9% susceptible isolates. The highest MIC90 against all isolates combined was 64 µg/mL for nitrofurantoin and the highest percentage of resistance was obtained with trimethoprim-sulfamethoxazole with 29.5%. Resistance towards ceftriaxone and ciprofloxacin was 19.6% and 26.1%, respectively.TableConclusionOverall, mecillinam showed the lowest MIC90 and a comparable susceptibility profile (94.5 % susceptible and 4.0 % resistant) to fosfomycin (i.e. 95.7% and 2.0% resistant) susceptible isolates). Resistance to ceftriaxone, ciprofloxacin and trimethoprim/sulfamethoxazole around or above 20% is concerning for their clinical usage to treat urinary tract infections. These encouraging susceptibility data warrant further studies to support the clinical development of mecillinam/pivmecillinam for the treatment of UTI in the USA.DisclosuresStephen Hawser, PhD, Tetraphase Pharmaceuticals (Scientific Research Study Investigator) Cedric Charrier, PhD, IHMA (Employee)Utility Therapeutics (Independent Contractor) Cyntia De Piano, PhD, IHMA (Employee)Utility Therapeutics (Independent Contractor) Morton Alexander, PhD, Utility Therapeutics (Employee, Shareholder) Anne Santerre Henriksen, MS, Maxel Consulting ApS (Employee)Utility Therapeutics (Independent Contractor)

BackgroundThe incidence of infections caused by multidrug-resistant Acinetobacter baumannii is increasing at an alarming rate in Southeast Asia and other parts of the world. Sulbactam (SUL) has intrinsic antibacterial activity against A. baumannii; however, the prevalence of β-lactamases in this species has limited its therapeutic use. Durlobactam (ETX2514, DUR) is a novel β-lactamase inhibitor with broad-spectrum activity against Ambler class A, C and D β-lactamases. DUR restores SUL in vitro activity against multidrug-resistant A. baumannii. Against >3,600 globally diverse, clinical isolates from 2012–2017, addition of 4 mg/L DUR reduced the SUL MIC90 from >32 to 2 mg/L. SUL-DUR is currently in Phase 3 clinical development for the treatment of infections caused by carbapenem-resistant Acinetobacter spp.The goal of this study was to determine the activity of SUL-DUR and comparator antibiotics (amikacin (AMK), ampicillin-sulbactam (AMP-SUL), cefoperazone-sulbactam (CFP-SUL) and meropenem (MEM)) against A. baumannii isolated from hospitalized patients in India.MethodsA total of 121 clinical A. baumannii isolates from multiple hospital settings and infection sources were collected between 2016–2019 from six geographically diverse hospitals in India. Species identification was performed by MALDI-TOF. Susceptibility of these isolates to SUL-DUR (10µg/10µg) and comparator antibiotics was determined by disk diffusion using CLSI methodology and interpretive criteria, except for CFP-SUL, for which resistance was defined using breakpoints from the CFP-SUL package insert.ResultsAs shown in Table 1, resistance of this collection of isolates to marketed agents was extremely high. In contrast, based on preliminary breakpoint criteria, only 11.5% of isolates were resistant to SUL-DUR.ConclusionThe in vitro antibacterial activity of SUL-DUR was significantly more potent than comparator agents against multidrug-resistant A. baumannii isolates collected from diverse sites in India. These data support the continued development of SUL-DUR for the treatment of antibiotic-resistant infections caused by A. baumannii.DisclosuresAll authors: No reported disclosures.

BackgroundThe development of new anti-infectives has increased rapidly over the past ten years. The need to support these important, life-saving products has increased as well. The STAR program was developed in 2018 to provide a repository of recent clinical fungal isolates with known susceptibility profiles and to monitor resistance trends over time. STAR reports the susceptibility patterns of the earliest STAR data concerning echinocandins, second-generation triazoles, and fluconazole against clinical Candida albicans and non-albicans strains including C. auris from worldwide sources.MethodsClinical isolates of Candida spp. (n = 203, from 2017–2018) from culture KOL investigator sites in the United States, Asia and the EU, were tested. Of these, 203 were isolated from blood or body tissues, and the remaining 11 from miscellaneous sources. Species distribution included mainly C. albicans, C. glabrata, C. krusei, C. lusitaniae, C. parapsilosis, C. tropicalis, and the emerging pathogen C. auris. Antifungals tested were amphotericin B (AMB), anidulafungin (ANID), fluconazole (FLU), isavuconazole (ISA), posaconazole (POS), and voriconazole (VOR). All testing was performed according to CLSI M27-A4 methodology.ResultsOverall, MIC50, MIC90, MIC range and percent susceptibility for each drug are listed in Table 1. Our data showed that for ANID, ISA and POS ≥ 93% of isolates were susceptible. While 84 and 88% were susceptible to FLU and VOR, respectively. Moreover, only 78% of isolates were susceptible to AMB. Interestingly, our data show that C. auris isolates were resistant to at least 1 antifungal with 15% of the C. auris strains (n = 40) showing multidrug resistance.ConclusionOngoing antifungal resistance surveillance like STAR is of utmost importance in order to monitor the efficacy of traditional empirical therapy and for the development of novel antifungal agents. This repository and ongoing STAR study will provide a resource to better support the biopharmaceutical industry’s goals to develop new and more potent antifungal agents. STAR will continue to monitor yeasts and will also include more unusual fungi including Mucor, Rhizopus amongst others.DisclosuresAll authors: No reported disclosures.

Infections caused by carbapenem-resistant Enterobacteriaceae (CRE) are increasingly prevalent and have become a major worldwide threat to human health. Carbapenem resistance is driven primarily by the acquisition of β-lactamase enzymes, which are able to degrade carbapenem antibiotics (hence termed carbapenemases) and result in high levels of resistance and treatment failure. Clinically relevant carbapenemases include both serine β-lactamases (SBLs; e.g., KPC-2 and OXA-48) and metallo-β-lactamases (MBLs), such as NDM-1. MBL-producing strains are endemic within the community in many Asian countries, have successfully spread worldwide, and account for many significant CRE outbreaks. Recently approved combinations of β-lactam antibiotics with β-lactamase inhibitors are active only against SBL-producing pathogens. Therefore, new drugs that specifically target MBLs and which restore carbapenem efficacy against MBL-producing CRE pathogens are urgently needed. Here we report the discovery of a novel MBL inhibitor, ANT431, that can potentiate the activity of meropenem (MEM) against a broad range of MBL-producing CRE and restore its efficacy against an Escherichia coli NDM-1-producing strain in a murine thigh infection model. This is a strong starting point for a chemistry lead optimization program that could deliver a first-in-class MBL inhibitor-carbapenem combination. This would complement the existing weaponry against CRE and address an important and growing unmet medical need.

This article describes the preparation of tosyl-activated nonmagnetic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) [P(HEMA-GMA)] microspheres by dispersion polymerization and tosyl-activated magnetic poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) [P(HEMA-EDMA)] microspheres by multistep swelling polymerization method and precipitation of iron oxide inside the pores. These new approaches show that monodisperse microspheres, 2.3 µm, respectively 4.1 µm, in diameter can be produced in high yields avoiding aggregation and with the advantage of being free of aromatic moieties. To demonstrate their potential for diagnostic applications, both types of microparticles have been coated with capture and detection antibodies (DAs), respectively. Immunoassay protocols have then been developed for the dosage of ferritin using an automated affinity platform combining microchannel chips and electrochemical detection. The assay performance using the above magnetic microspheres has been compared with that obtained with commercial tosyl-activated beads. Finally, the possibility to combine functionalized magnetic and nonmagnetic microspheres has been evaluated in view of amplifying the number of enzymatic labels in the immuno-complex. At a ferritin concentration of 119.6 ng/mL, a signal-to-noise ratio of 150.5 is obtained using 0.2 mg/mL of anti-ferritin-coated P(HEMA-GMA)-DA microspheres against a value of 158.8 using free DA in solution.

Disposable plastic electrospray chips are particularly attractive for the automated analysis of organic compounds and organometallic compounds. Automated multi-track chip-based infusion electrospray mass spectrometry of low molecular weight compounds using an eight-channel plastic chip is presented. For that purpose, the commercial interface of a triple quadrupole linear ion trap was modified. A dual-channel plastic microchip, where two physically separated channels arrive very close to each other at the chip tip, was used to perform lock-mass accurate mass measurements on a quadrupole-time-of-flight instrument. The same chip was used to demonstrate the formation of an organometallic complex in solution on the chip tip. Furthermore, the potential to control the flow rate of each channel individually, which opens new possibilities in the study of supramolecular complexes, is discussed.

Protein oxidation mechanisms result in a wide array of modifications, from backbone cleavage or protein crosslinking to more subtle modifications such as side chain oxidations. Protein oxidation occurs as part of normal regulatory processes, as a defence mechanism against oxidative stress, or as a deleterious processes when antioxidant defences are overcome. Because blood is continually exposed to reactive oxygen and nitrogen species, blood proteomics should inherently adopt redox proteomic strategies. In this review, we recall the biochemical basis of protein oxidation, review the proteomic methodologies applied to analyse redox modifications, and highlight some physiological and in vitro responses to oxidative stress of various blood components.

We present the state-of-the-art in miniaturized sample preparation, immunoassays, one-dimensional and multidimensional analyte separations, and coupling of microdevices with electrospray ionization-mass spectrometry. Hyphenation of these different techniques and their relevance to proteomics will be discussed. In particular, we will show that analytical performances of microfluidic analytical systems are already close to fulfill the requirements for proteomics, and that miniaturization results at the same time in a dramatic increase in analysis throughput. Throughout this review, some examples of analytical operations that cannot be achieved without microfluidics will be emphasized. Finally, conditions for the spreading of microanalytical systems in routine proteomic labs will be discussed.

From February 1989 to January 1990, the Swiss Contact Dermatitis Research Group conducted a 1-year study to examine the frequency of sensitization to a series of 13 common preservatives. A group of 2295 consecutive outpatients with suspected allergic contact dermatitis (age range 7-90 years, with a mean age of 42; 911 males, 1384 females) was tested. The %s of positive reactions to the preservatives studied are as follows, in descending order: formaldehyde 5.7%, benzalkonium chloride 5.5%, Kathon CG 5.5%, thimerosal 4.2%, chlorhexidine digluconate 2.0%, DMDM hydantoin 1.7%, paraben mix 1.7%, chloroacetamide 1.5%, Bronopol 1.2%, imidazolidinyl urea 1.0%, quaternium 15 1.0%, triclosan 0.8%, 2,4-dichlorobenzyl alcohol 0.4%. These relatively high values suggest a heavy exposure of the Swiss population to topical preservatives. Compared to previous studies, the sensitization rate to Kathon CG has stabilized in Switzerland over the last 2 years. Sensitization to formaldehyde portrayed impressive geographical variation, with sensitization rates up to 9% in western and only 3% in eastern Switzerland. The low sensitization rate to parabens argues for their inclusion in a medicament or preservative series, rather than in the standard series.