Detection of extended-spectrum β-lactamase and carbapenemase activity in Gram-negative bacilli using liquid chromatography - tandem mass spectrometry

PURPOSE: Several mass spectrometry-based methods for antimicrobial sensitivity testing have been described in recent years. They offer an alternative to commercially available testing systems which were considered to have disadvantages in terms of cost- and time-efficiency. The aim of this study was to develop a LC-MS/MS-based antibiotic hydrolysis assay for evaluating antimicrobial resistance of Gram-negative bacteria. METHODS: Four species of Gram-negative bacilli (Klebsiella pneumoniae, Escherichia coli, Providencia stuartii and Acinetobacter baumannii) were tested against six antibiotics from three different classes: ampicillin, meropenem, imipenem, ceftazidime, ceftriaxone and cefepime. Bacterial suspensions from each species were incubated with a mixture of the six antibiotics. Any remaining antibiotic following incubation were measured using LC-MS/MS. The results were interpreted using measurements obtained for an E. coli strain sensitive to all antibiotics and expressed as percentage of hydrolyzed antibiotic. These were subsequently compared to commercially-available system for the bacteria identification and susceptibility testing. RESULTS: Overall, LC-MS/MS assay and commercial antimicrobial susceptibility platform results showed good agreement in terms of an organism being resistant/sensitive to an antibiotic. The time required to complete the LC-MS/MS-based hydrolysis test was under 5 h, significantly shorter that commercially available susceptibility testing platforms. CONCLUSION: By using a sensitive strain for results interpretation and simultaneous use of multiple antibiotics, the proposed protocol offers improved robustness and multiplexing over previously described methods for antibiotic sensitivity testing. Nevertheless, further research is needed before routine assimilation of the method, especially for strains with intermediate resistance

Exploring behaviors of stochastic differential equation models of biological systems using change of measures

Stochastic Differential Equations (SDE) are often used to model the stochastic dynamics of biological systems. Unfortunately, rare but biologically interesting behaviors (e.g., oncogenesis) can be difficult to observe in stochastic models. Consequently, the analysis of behaviors of SDE models using numerical simulations can be challenging. We introduce a method for solving the following problem: given a SDE model and a high-level behavioral specification about the dynamics of the model, algorithmically decide whether the model satisfies the specification. While there are a number of techniques for addressing this problem for discrete-state stochastic models, the analysis of SDE and other continuous-state models has received less attention. Our proposed solution uses a combination of Bayesian sequential hypothesis testing, non-identically distributed samples, and Girsanov's theorem for change of measures to examine rare behaviors. We use our algorithm to analyze two SDE models of tumor dynamics. Our use of non-identically distributed samples sampling contributes to the state of the art in statistical verification and model checking of stochastic models by providing an effective means for exposing rare events in SDEs, while retaining the ability to compute bounds on the probability that those events occur

Multinational prospective cohort study of rates and risk factors for ventilator-associated pneumonia over 24 years in 42 countries of Asia, Africa, Eastern Europe, Latin America, and the Middle East: Findings of the International Nosocomial Infection Control Consortium (INICC)

Objective: Rates of ventilator-associated pneumonia (VAP) in low- and middle-income countries (LMIC) are several times above those of high-income countries. The objective of this study was to identify risk factors (RFs) for VAP cases in ICUs of LMICs. Design: Prospective cohort study. Setting: This study was conducted across 743 ICUs of 282 hospitals in 144 cities in 42 Asian, African, European, Latin American, and Middle Eastern countries. Participants: The study included patients admitted to ICUs across 24 years. Results: In total, 289,643 patients were followed during 1,951,405 patient days and acquired 8,236 VAPs. We analyzed 10 independent variables. Multiple logistic regression identified the following independent VAP RFs: male sex (adjusted odds ratio [aOR], 1.22; 95% confidence interval [CI], 1.16-1.28; P <.0001); longer length of stay (LOS), which increased the risk 7% per day (aOR, 1.07; 95% CI, 1.07-1.08; P <.0001); mechanical ventilation (MV) utilization ratio (aOR, 1.27; 95% CI, 1.23-1.31; P <.0001); continuous positive airway pressure (CPAP), which was associated with the highest risk (aOR, 13.38; 95% CI, 11.57-15.48; P <.0001)Revisión por pare

International Nosocomial Infection Control Consortium report, datasummary of 50 countries for 2010-2015 : Device-associated module

Q3Artículo original1495-1504Background: We report the results of International Nosocomial Infection Control Consortium (INICC) sur-veillance study from January 2010-December 2015 in 703 intensive care units (ICUs) in Latin America,Europe, Eastern Mediterranean, Southeast Asia, and Western Pacific.Methods:During the 6-year study period, using Centers for Disease Control and Prevention National Health-care Safety Network (CDC-NHSN) definitions for device-associated health care-associated infection (DA-HAI), we collected prospective data from 861,284 patients hospitalized in INICC hospital ICUs for an aggregateof 3,506,562 days.Results:Although device use in INICC ICUs was similar to that reported from CDC-NHSN ICUs, DA-HAIrates were higher in the INICC ICUs: in the INICC medical-surgical ICUs, the pooled rate of central line-associated bloodstream infection, 4.1 per 1,000 central line-days, was nearly 5-fold higher than the 0.8per 1,000 central line-days reported from comparable US ICUs, the overall rate of ventilator-associatedpneumonia was also higher, 13.1 versus 0.9 per 1,000 ventilator-days, as was the rate of catheter-associated urinary tract infection, 5.07 versus 1.7 per 1,000 catheter-days. From blood cultures samples,frequencies of resistance ofPseudomonasisolates to amikacin (29.87% vs 10%) and to imipenem (44.3%vs 26.1%), and ofKlebsiella pneumoniaeisolates to ceftazidime (73.2% vs 28.8%) and to imipenem (43.27%vs 12.8%) were also higher in the INICC ICUs compared with CDC-NHSN ICUs.Conclusions:Although DA-HAIs in INICC ICU patients continue to be higher than the rates reported inCDC-NSHN ICUs representing the developed world, we have observed a significant trend toward the re-duction of DA-HAI rates in INICC ICUs as shown in each international report. It is INICC’s main goal tocontinue facilitating education, training, and basic and cost-effective tools and resources, such as stan-dardized forms and an online platform, to tackle this problem effectively and systematically

SEGNALI DI VITA

Cosa significa innamorarsi in giardino? uno stato d’animo che facilita le relazioni? una percezione alterata della realtà che ci circonda? una ricerca dell’equilibrio interiore o esteriore? oppure significa trovare un equilibrio tra il dentro e il fuori, un’intesa tra natura e artificio? Durante la ricerca di questo equilibrio il più delle volte siamo noi a cercare una relazione con la natura, senza accorgerci che ogni giorno è la natura che entra in relazione con noi senza chiedercelo. Cerchiamo di riproporre il fenomeno dell’amore per la vita, che riesce a vincere le barriere poste dal’uomo, attraverso l’immagine della vegetazione spontanea che riesce sempre a trovare il proprio spazio per crescere forte, rigogliosa e bella. Questa sua forza di solito ci sfugge. Le barriere fisiche esistono ma la vegetazione riesce a valicarle mentre le barriere mentali sono ancora difficili da superare. Di solito la vegetazione spontanea viene combattuta e vista come un nemico invece di capirne le potenzialità date dalla biodiversita, dall’estetica e dal carattere autoctono e purtroppo non è mai oggetto di progetto. Per noi diventa invece il cuore pulsante del nostro giardino, un inno alla vita, all’amore per la vita che la natura c’insegna

Multidrug-Resistant Gram-Negative Bacilli: A Retrospective Study of Trends in a Tertiary Healthcare Unit

Background and objective: Bacterial multidrug resistance is particularly common in Gram-negative bacilli (GNB), with important clinical consequences regarding their spread and treatment options. The aim of this study was to investigate the trend of multidrug-resistant GNB (MDR-GNB) in high-risk hospital departments, between 2000&#8315;2015, in intervals of five years, with the intention of improving antibiotic therapy policies and optimising preventive and control practices. Materials and methods: This is an observational, retrospective study performed in three departments of the most important tertiary healthcare unit in the southwestern part of Romania: the Intensive Care Unit (ICU), the General Surgery Department (GSD), and the Nutrition and Metabolic Diseases Department (NMDD). MDR was defined as acquired resistance to at least one agent in three or more antimicrobial categories. Trends over time were determined by the Cochran&#8315;Armitage trend test and linear regression. Results: During the study period, a total of 2531 strains of MDR-GNB were isolated in 1999 patients: 9.20% in 2000, 18.61% in 2005, 37.02% in 2010, and 35.17% in 2015. The most significant increasing trend was recorded in the ICU (gradient = 7.63, R&#178; = 0.842, p &lt; 0.001). The most common MDR-GNB in the ICU was isolated from bronchoalveolar aspiration samples. Concerning the proportion of different species, most of the changes were recorded in the ICU, where a statistically significant increasing trend was observed for Proteus mirabilis (gradient = 2.62, R2 = 0.558, p &lt; 0.001) and Acinetobacter baumannii (gradient = 2.25, R2 = 0.491, p &lt; 0.001). Analysis of the incidence of the main resistance phenotypes proportion identified a statistically significant increase in carbapenem resistance in the ICU (Gradient = 8.27, R&#178; = 0.866, p &lt; 0.001), and an increased proportion of aminoglycoside-resistant strains in all three departments, but more importantly in the ICU and GSD. Conclusion: A statistically significant increasing trend was observed in all three departments; the most significant one was recorded in the ICU, where after 2010, carbapenem-resistant strains were isolated