ABSTRACT
BACKGROUND: Ceftolozane/tazobactam (C-T) is a novel beta-lactam/beta-lactamase inhibitor combination approved for the treatment of various infections caused by difficult-to-treat Pseudomonas aeruginosa. In critically ill patients, C-T may exhibit significant pharmacokinetic variability, both between individuals and within individuals, warranting therapeutic drug monitoring for clinical purposes. We aim to develop and validate a novel and sensitive analytical method for concurrently determining C and T in human plasma microsamples (3 µL). METHODS: The method was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with positive electrospray ionization and multiple reaction monitoring (MRM) detection modes, employing specific mass transitions for both drugs. Sample preparation was simple, and the chromatographic run lasted only 4 minutes. Validation was conducted according to European Medicines Agency (EMA) guidelines, encompassing specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, limit of quantification, and drug stability. The validated method was applied to measure C and T in 32 plasma samples collected from critically ill patients with multidrug-resistant, gram-negative, bacterial infections. RESULTS: The method ensured accurate (BIAS% 2.1-9.6 for C and -2.2 to 15.2 for T) and precise intraday CV% for C: 6.7-5.5; for T: 1.3-8.9; interday CV% for C 6.0-10.8; for T 4.1-10.2) measurements of C-T over a wide concentration range (0.2-200.0 mg/L for C and 0.1-100.0 mg/L for T). Overall, the recovery at quality control concentration levels was high for both C and T (mean values: 90-91 for C and 89-92 for T). Analyte stability was satisfactory in both human plasma and extracts under various storage conditions. The clinical applicability of the assay was confirmed by the reliably quantifying C and T in clinical plasma samples. CONCLUSIONS: The developed and validated LC-MS/MS method is sensitive and suitable for monitoring C and T in human plasma microsamples.
ABSTRACT
The aim of this study was to develop and validate a fast and sensitive bioanalytical method for the accurate quantification of fosfomycin concentrations in human prostatic tissue. The sample preparation method only required milligrams of tissue sample. Each sample was mixed with two times its weight of water and homogenized. A methanol solution that was three times the volume of the internal standard (fosfomycin-13C3) was added, followed by vortex mixing and centrifugation. After its extraction from the homogenized prostatic tissue, fosfomycin was quantified by means of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) triple quadrupole system operating in negative electrospray ionization and multiple reaction monitoring detection mode. The analytical procedure was successfully validated in terms of specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, limit of quantification, and stability, according to EMA guidelines. The validation results, relative to three QC levels, were 9.9% for both the within-day and inter-day accuracy (BIAS%); 9.8% for within-day precision; and 9.9 for between-day precision. A marked matrix effect was observed in the measurements but was corrected by normalization with the internal standard. The average total recovery was high (approximatively 97% at the three control levels). The dynamic range of the method was 0.1-20 µg/g (R2 of 0.999). Negligible carry-over was observed after the injection of highly concentrated samples. F in the sample homogenate extracts was stable at 10 °C and 4 °C for at least 24 h. In the tissue sample freeze-thaw experiments, a significant decrease in F concentrations was observed after only two cycles from -80 °C to room temperature. The novel method was successfully applied to measure fosfomycin in prostatic tissue samples collected from 105 patients undergoing prostatectomy.
ABSTRACT
BACKGROUND: Fosfomycin is an antibiotic recently repurposed as a potential combination treatment for difficult-to-treat Gram-negative bacterial infections. The pharmacokinetic features of fosfomycin have demonstrated that different pathophysiologic alterations may affect its exposure. Therapeutic drug monitoring may improve real-time management of fosfomycin therapy in different clinical scenarios. OBJECTIVES: To develop and validate a fast and sensitive liquid chromatography - tandem mass spectrometry method for measuring fosfomycin in human plasma microsamples (3 µL). METHODS: Analysis was preceded by a user-friendly pre-analytical single-step process performed via a rapid chromatographic run of 2.5 minutes, followed by negative electrospray ionization and detection on a high-sensitivity triple quadrupole tandem mass spectrometer operated in the multiple reaction monitoring mode. European Medicines Agency guidelines were used to validate the specificity, sensitivity, linearity, precision, accuracy, matrix effects, extraction recovery, limits of quantification, and stability of the analytical method. RESULTS: The new assay produced accurate (BIAS%: 0.9-9.1) and precise (coefficient of variation [CV]%: 8.1-9.5) measurements of fosfomycin over a concentration range of 1-1000 mg/L. Overall, analyte recovery was consistent (mean values: 91.2%-97.2%) at all tested concentration levels. The analyte was also stable in human plasma and the final extract under various storage conditions. The clinical applicability of the assay was confirmed through quantitation of plasma samples obtained from patients. CONCLUSIONS: A sensitive liquid chromatography - tandem mass spectrometry method for measuring fosfomycin in plasma was developed and validated according to the European Medicines Agency criteria. Quantitation of fosfomycin in clinical plasma samples confirmed that the assay is suitable for therapeutic drug monitoring in clinical scenarios.
ABSTRACT
Airborne-mediated microbial diseases represent one of the major challenges to public health. Ultraviolet C radiation (UVC) is among the different sanitation techniques useful to reduce the risk of infection in healthcare facilities. Previous studies about the germicidal activity of UVC were mainly performed in artificial settings or in vitro models. This study aimed to assess the sanitizing effectiveness of a UVC device (SanificaAria 200, Beghelli, Valsamoggia, Bologna, Italy) in 'real-life' conditions by evaluating its ability to reduce microbial loads in several hospital settings during routine daily activities. The efficacy of the UVC lamp in reducing the bacterial component was evaluated by microbial culture through the collection of air samples in different healthcare settings at different times (30 min-24 h) after turning on the device. To assess the anti-viral activity, air samplings were carried out in a room where a SARS-CoV-2-positive subject was present. The UVC device showed good antibacterial properties against a wide range of microbial species after 6 h of activity. It was effective against possible multi-drug resistant microorganisms (e.g., Pseudomonas spp., Acinetobacter spp.) and spore-forming bacteria (e.g., Bacillus spp.). In addition, the UVC lamp was able to inactivate SARS-CoV-2 in just one hour. Thanks to its effectiveness and safety, SanificaAria 200 could be useful to inactivate airborne pathogens and reduce health risks.
ABSTRACT
Meropenem (MRP)-Vaborbactam (VBR) is a novel beta-lactam/beta-lactamase inhibitor used for the management of difficult-to-treat Gram-negative infections. Among critically ill patients, MRP-VBR shows remarkable inter-individual variability in pharmacokinetic behavior, thus justifying the implementation of therapeutic drug monitoring (TDM) for improving real-time management in different challenging scenarios. In this study, we developed and validated a fast and sensitive Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) method for the simultaneous quantification of MRP and VBR in human plasma microsamples of 3 microliters. The analysis required only a single-step sample preparation and was performed by means of a fast chromatographic run of 4 min, followed by positive electrospray ionization and detection on a high-sensitivity triple quadrupole tandem mass spectrometer operated in multiple reaction monitoring modes. The straightforward analytical procedure was successfully validated, based on the EMA guidelines, in terms of specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, the limit of quantification, and stability. The novel method was successfully applied for simultaneously measuring MRP and VBR concentrations in more than 42 plasma samples collected from critically ill patients affected by carbapenem-resistant Gram-negative bacteria infections.