Bacteria can be refractory to antibiotics due to a sub-population of dormant cells, called persisters that are highly tolerant to antibiotic exposure. The low frequency and transience of the ...antibiotic tolerant "persister" trait has complicated elucidation of the mechanism that controls antibiotic tolerance. In this study, we show that 2' Amino-acetophenone (2-AA), a poorly studied but diagnostically important small, volatile molecule produced by the recalcitrant gram-negative human pathogen Pseudomonas aeruginosa, promotes antibiotic tolerance in response to quorum-sensing (QS) signaling. Our results show that 2-AA mediated persister cell accumulation occurs via alteration of the expression of genes involved in the translational capacity of the cell, including almost all ribosomal protein genes and other translation-related factors. That 2-AA promotes persisters formation also in other emerging multi-drug resistant pathogens, including the non 2-AA producer Acinetobacter baumannii implies that 2-AA may play an important role in the ability of gram-negative bacteria to tolerate antibiotic treatments in polymicrobial infections. Given that the synthesis, excretion and uptake of QS small molecules is a common hallmark of prokaryotes, together with the fact that the translational machinery is highly conserved, we posit that modulation of the translational capacity of the cell via QS molecules, may be a general, widely distributed mechanism that promotes antibiotic tolerance among prokaryotes.
Background
Prospective randomized controlled studies have demonstrated that addition of chlorhexidine (CHG) dressings reduces the rate of catheter (central venous and arterial)-associated bloodstream ...infections (CABSIs). However, studies confirming their impact in a real-world setting are lacking.
Methods
We conducted a real-world data study evaluating the impact of incrementally introducing chlorhexidine dressings (sponge or gel) in addition to an ongoing catheter bundle on the rates of CABSI, expressed as incidence density rates per 1000 catheter-days measured as part of a surveillance program. Poisson regression models were used to compare infection rates over time. Both dressings were used simultaneously during one of the five study periods.
Results
From 2006 to 2014, 18,286 patients were admitted (91,292 ICU-days and 155,242 catheter-days). We recorded 111 CABSIs. We observed a progressive but significant decrease of CABSI rates from 1.48 (95% CI 1.09–2.01) without CHG dressings to 0.69 (95% CI 0.43–1.09) and 0.23 (95% CI 0.11–0.48) episodes per 1000 catheter-days when CHG sponge and CHG gel dressings were used (
p
= 0.0007;
p
< 0.001). A non-significant lower rate of infections occurred with CHG gel compared with CHG sponge dressings. An identical low rate of allergic skin reactions (0.3/1000 device-days) was observed with both types of CHX dressings. Post-study data until 2018 confirmed a sustained decrease of infection rates over 11 years.
Conclusions
The addition of chlorhexidine dressings to all CVC and arterial lines to an ongoing catheter bundle was associated with a sustained 11-year reduction of all catheter-associated bloodstream infections. This large real-world data study further supports the current recommendations for the systematic use of CHG dressings on all catheters of ICU patients.
Background The potential of phage therapy for the treatment of endovascular
infections remains to be evaluated. Methods and Results The efficacy of a phage cocktail combining
phage vB_SauH_2002 and
...phage 66 was evaluated against a methicillin-sensitive
strain in vitro and in vivo in a rodent model of experimental endocarditis. Six hours after bacterial challenge, animals were treated with (1) the phage cocktail. (2) subtherapeutic flucloxacillin dosage, (3) combination of the phage cocktail and flucloxacillin, or (4) saline. Bacterial loads in cardiac vegetations at 30 hours were the primary outcome. Secondary outcomes were phage loads at 30 hours in cardiac vegetations, blood, spleen, liver, and kidneys. We evaluated phage resistance 30 hours post infection in vegetations of rats under combination treatment. In vitro, phages synergized against
planktonic cells and the cocktail synergized with flucloxacillin to eradicated biofilms. In infected animals, the phage cocktail achieved bacteriostatic effect. The addition of low-dose flucloxacillin elevated bacterial suppression (∆ of -5.25 log
colony forming unit/g CFU/g versus treatment onset,
<0.0001) and synergism was confirmed (∆ of -2.15 log
CFU/g versus low-dose flucloxacillin alone,
<0.01). Importantly, 9/12 rats given the combination treatment had sterile vegetations at 30 hours. In vivo phage replication was partially suppressed by the antibiotic and selection of resistance to the
component of the phage cocktail occurred. Plasma-mediated inhibition of phage killing activity was observed in vitro. Conclusions Combining phages with a low-dose standard of care antibiotic represents a promising strategy for the treatment of
infective endocarditis.
Antibiotic resistance and its rapid dissemination around the world threaten the efficacy of currently-used medical treatments and call for novel, innovative approaches to manage multi-drug resistant ...infections. Phage therapy, i.e., the use of viruses (phages) to specifically infect and kill bacteria during their life cycle, is one of the most promising alternatives to antibiotics. It is based on the correct matching between a target pathogenic bacteria and the therapeutic phage. Nevertheless, correctly matching them is a major challenge. Currently, there is no systematic method to efficiently predict whether phage-bacterium interactions exist and these pairs must be empirically tested in laboratory. Herein, we present our approach for developing a computational model able to predict whether a given phage-bacterium pair can interact based on their genome.
Based on public data from GenBank and phagesDB.org, we collected more than a thousand positive phage-bacterium interactions with their complete genomes. In addition, we generated putative negative (i.e., non-interacting) pairs. We extracted, from the collected genomes, a set of informative features based on the distribution of predictive protein-protein interactions and on their primary structure (e.g. amino-acid frequency, molecular weight and chemical composition of each protein). With these features, we generated multiple candidate datasets to train our algorithms. On this base, we built predictive models exhibiting predictive performance of around 90% in terms of F1-score, sensitivity, specificity, and accuracy, obtained on the test set with 10-fold cross-validation.
These promising results reinforce the hypothesis that machine learning techniques may produce highly-predictive models accelerating the search of interacting phage-bacteria pairs.
Background. Recurrent therapeutic failures reported for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infective endocarditis (IE) with vancomycin may be due to poor bactericidal ...activity. Alternative antibacterial approaches using bacteriophages may overcome this limitation. Objectives. An experimental rat model of MRSA IE (EE) was used to examine the efficacy of vancomycin combined with a 1:1 bacteriophage (phage) cocktail composed of Herelleviridae vB_SauH_2002 and Routreeviridae 66. Methods. Six hours after inoculation with ca. 5 log10 colony forming units (CFU) of MRSA strain AW7, animals were treated with either: (i) saline, (ii) an equimolar two-phage cocktail (bolus of 1 mL followed by a 0.3 mL/h continuous infusion of 10 log10 plaque forming units (PFU)/mL phage suspension), (iii) vancomycin (at a dose mimicking the kinetics in humans of 0.5 g b.i.d.), or (iv) a combination of both. Bacterial loads in vegetations, and phage loads in vegetations, liver, kidney, spleen, and blood, were measured outcomes. Results. Phage cocktail alone was unable to control the growth of strain AW7 in cardiac vegetations. However, when combined with subtherapeutic doses of vancomycin, a statistically significant decrease of ∆4.05 ± 0.94 log10 CFU/g at 24 h compared to placebo was detected (p < 0.001). The administration of vancomycin was found to significantly impact on the local concentrations of phages in the vegetations and in the organs examined. Conclusions. Lytic bacteriophages as an adjunct treatment to the standard of care antibiotics could potentially improve the management of MRSA IE. Further studies are needed to investigate the impact of antibiotics on phage replication in vivo.
Abstract
Background
Accurate biomarkers to diagnose infection are lacking. Studies reported good performance of pancreatic stone protein (PSP) to detect infection. The objective of the study was to ...determine the performance of PSP in diagnosing infection across hospitalized patients and calculate a threshold value for that purpose.
Methods
A systematic search across Cochrane Central Register of Controlled Trials and MEDLINE databases (1966–March 2019) for studies on PSP published in English using ‘pancreatic stone protein’, ‘PSP’, ‘regenerative protein’, ‘lithostatin’ combined with ‘infection’ and ‘sepsis’ found 44 records. The search was restricted to the five trials that evaluated PSP for the initial detection of infection in hospitalized adults. Individual patient data were obtained from the investigators of all eligible trials. Data quality and validity was assessed according to PRISMA guidelines. We choose a fixed-effect model to calculate the PSP cut-off value that best discriminates infected from non-infected patients.
Results
Infection was confirmed in 371 of 631 patients. The median (IQR) PSP value of infected versus uninfected patients was 81.5 (30.0–237.5) versus 19.2 (12.6–33.57) ng/ml, compared to 150 (82.70–229.55) versus 58.25 (15.85–120) mg/l for C-reactive protein (CRP) and 0.9 (0.29–4.4) versus 0.15 (0.08–0.5) ng/ml for procalcitonin (PCT). Using a PSP cut-off of 44.18 ng/ml, the ROC AUC to detect infection was 0.81 (0.78–0.85) with a sensitivity of 0.66 (0.61–0.71), specificity of 0.83 (0.78–0.88), PPV of 0.85 (0.81–0.89) and NPV of 0.63 (0.58–0.68). When a model combining PSP and CRP was used, the ROC AUC improved to 0.90 (0.87–0.92) with higher sensitivity 0.81 (0.77–0.85) and specificity 0.84 (0.79–0.90) for discriminating infection from non-infection. Adding PCT did not improve the performance further.
Conclusions
PSP is a promising biomarker to diagnose infections in hospitalized patients. Using a cut-off value of 44.18 ng/ml, PSP performs better than CRP or PCT across the considered studies. The combination of PSP with CRP further enhances its accuracy.
Infections caused by multidrug-resistant bacteria are a major clinical challenge. Phage therapy is a promising alternative antibacterial strategy.
To evaluate the efficacy of intravenous phage ...therapy for the treatment of ventilator-associated pneumonia due to methicillin-resistant
in rats.
In a randomized, blinded, controlled experimental study, we compared intravenous teicoplanin (3 mg/kg,
= 12), a cocktail of four phages (2-3 × 10
plaque-forming units/ml of 2003, 2002, 3A, and K;
= 12), and a combination of both (
= 11) given 2, 12, and 24 hours after induction of pneumonia, and then once daily for 4 days. The primary outcome was survival at Day 4. Secondary outcomes were bacterial and phage densities in lungs and spleen, histopathological scoring of infection within the lungs, and inflammatory biomarkers in blood.
Treatment with either phages or teicoplanin increased survival from 0% to 58% and 50%, respectively (
< 0.005). The combination of phages and antibiotics did not further improve outcomes (45% survival). Animal survival correlated with reduced bacterial burdens in the lung (1.2 × 10
cfu/g of tissue for survivors vs. 1.2 × 10
cfu/g for nonsurviving animals;
< 0.0001), as well as improved histopathological outcomes. Phage multiplication within the lung occurred during treatment. IL-1β increased in all treatment groups over the course of therapy.
Phage therapy was as effective as teicoplanin in improving survival and decreasing bacterial load within the lungs of rats infected with methicillin-resistant
. Combining antibiotics with phage therapy did not further improve outcomes.
The early recognition and management of sepsis improves outcomes. Biomarkers may help in identifying earlier sub-clinical signs of sepsis. We explored the potential of serial measurements of ...C-reactive protein (CRP), procalcitonin (PCT) and pancreatic stone protein (PSP) for the early recognition of sepsis in patients hospitalized in the intensive care unit (ICU).
This was a multicentric international prospective observational clinical study conducted in 14 ICUs in France, Switzerland, Italy, and the United Kingdom. Adult ICU patients at risk of nosocomial sepsis were included. A biomarker-blinded adjudication committee identified sepsis events and the days on which they began. The association of clinical sepsis diagnoses with the trajectories of PSP, CRP, and PCT in the 3 days preceding these diagnoses of sepsis were tested for markers of early sepsis detection. The performance of the biomarkers in sepsis diagnosis was assessed by receiver operating characteristic (ROC) analysis.
Of the 243 patients included, 53 developed nosocomial sepsis after a median of 6 days (interquartile range, 3-8 days). Clinical sepsis diagnosis was associated with an increase in biomarkers value over the 3 days preceding this diagnosis PSP (p = 0.003), PCT (p = 0.025) and CRP (p = 0.009). PSP started to increase 5 days before the clinical diagnosis of sepsis, PCT 3 and CRP 2 days, respectively. The area under the ROC curve at the time of clinical sepsis was similar for all markers (PSP, 0.75; CRP, 0.77; PCT, 0.75).
While the diagnostic accuracy of PSP, CRP and PCT for sepsis were similar in this cohort, serial PSP measurement demonstrated an increase of this marker the days preceding the onset of signs necessary to clinical diagnose sepsis. This observation justifies further evaluation of the potential clinical benefit of serial PSP measurement in the management of critically ill patients developing nosocomial sepsis. Trial registration The study has been registered at ClinicalTrials.gov (no. NCT03474809), on March 16, 2018. https://www.clinicaltrials.gov/ct2/show/NCT03474809?term=NCT03474809&draw=2&rank=1 .
Excessive duration of antibiotic treatment is a major factor for inappropriate antibiotic consumption. Although in some instances shorter antibiotic courses are as efficient as longer ones, no ...specific recommendations as to the duration of antimicrobial treatment for bloodstream infections currently exist. In the present study, we investigated the effect of antibiotic treatment duration on in-hospital mortality using retrospective data from two cohorts that included patients with bacteremia at two Swiss tertiary Intensive Care Units (ICUs).
Overall 8227 consecutive patients requiring ICU admission were screened for bacteremia between 01/2012–12/2013 in Lausanne and between 07/2016–05/2017 in Bern. Patients with an infection known to require prolonged treatment or having single positive blood culture with common contaminant pathogens were excluded. The primary outcome of interest was the time from start of antimicrobial treatment to in-hospital death or hospital discharge, whichever comes first. The predictor of interest was adequate antimicrobial treatment duration, further divided into shorter (≤10 days) and longer (>10 days) durations. A time-dependent Cox model and a cloning approach were used to address immortality bias. The secondary outcomes were the median duration of antimicrobial treatment for patients with bacteremia overall and stratified by underlying infectious syndrome and pathogens in the case of secondary bacteremia.
Out of the 707 patients with positive blood cultures, 382 were included into the primary analysis. Median duration of antibiotic therapy was 14 days (IQR, 7–20). Most bacteremia (84%) were monomicrobial; 18% of all episodes were primary bacteremia. Respiratory (28%), intra-abdominal (23%) and catheter infections (17%) were the most common sources of secondary bacteremia. Using methods to mitigate the risk of confounding associated with antibiotic treatment durations, shorter versus longer treatment groups showed no differences in in-hospital survival (time-dependent Cox-model: HR 1.5, 95% CI (0.8, 2.7), p = 0.20; Cloning approach: HR 1.0, 95% CI (0.7,1.5) p = 0.83). Sensitivity analyses showed that the interpretation did not change when using a 7 days cut-off.
In this restrospective study, we found no evidence for a survival benefit of longer (>10 days) versus shorter treatment course in ICU patients with bacteremia.
The study was retrospectively registered on clinicatrials.gov (NCT05236283), 11 February 2022. The respective cantonal ethics commission (KEK Bern # 2021–02302) has approved the study.
•No specific recommendations as to the duration of antimicrobial treatment for bloodstream infections currently exist•Using an RCT emulating cloning approach we analyzed the effect on mortality for adequate antibiotic treatment duration•We found no survival benefit of longer (>10 days) versus shorter treatment course in ICU patients with bacteremia
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