Publications by authors named "Spyros Pournaras"

Article Synopsis
  • The study developed a microbroth assay to evaluate the host range and lytic activity of phages against carbapenemase-producing K. pneumoniae isolates, addressing limitations of the traditional agar overlay method.
  • The host range was tested on 11 specific phages using various concentrations and bacterial inocula, with analysis of growth inhibition over 6 and 24 hours.
  • Results showed significant differences in growth inhibition among phages and identified specific cutoffs for lysis detection, demonstrating the microbroth assay's effectiveness and reliability.
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Background: Studies link multidrug-resistant organism (MDRO) rectal colonization to increased infection risk, data from Greece, a country with high rates of MDRO, are limited.

Methods: We assessed bloodstream infection (BSI) risk following rectal colonization by MDROs across three Greek hospitals (2019-2022).

Results: Of 4,370 inpatients, 31.

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Article Synopsis
  • - After COVID-19 began, there was a significant increase in invasive fungal infections globally, but the specific situation in Greece regarding fungaemias remains unclear.
  • - An ongoing outbreak in a Greek hospital has led to 89 episodes of bloodstream infections over nearly three years, with these episodes occurring in waves linked to previous colonization peaks.
  • - Most fungal isolates were found to be resistant to fluconazole but sensitive to other antifungals, highlighting the importance of infection control and careful use of antifungal treatments to prevent resistance.
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  • Bacteriophage therapy shows promise against multidrug-resistant (MDR) pathogens, but its adoption in clinical practice is slowed due to a lack of familiarity with its pharmacokinetic (PK) and pharmacodynamic (PD) properties.
  • The unique characteristics of bacteriophages, such as their ability to replicate in host bacteria and their interaction with the immune system, make conventional PK/PD estimation methods inadequate.
  • Challenges in optimizing bacteriophage therapy include understanding diverse bacteriophage types and resistance development among MDR pathogens, necessitating further research for better application against infections.
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  • The Double-layer agar (DLA) overlay plaque assay is the traditional method for counting phages but is challenging and slow to conduct.
  • Researchers tested a new single-layer agar (SLA) assay with various phages and host isolates, comparing it to the standard DLA method.
  • The SLA-spot assay produced similar results to the DLA assay while requiring less media, costing less, and being ten times faster, making it a more efficient option for phage quantitation.
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  • The study analyzed the trends of candidaemia cases in a Greek hospital before and during the COVID-19 pandemic, revealing a significant increase in infection rates.
  • The incidence of candidaemia rose from 2.0 episodes per 10,000 hospital bed days before the pandemic to 5.1 during the late COVID-19 period, alongside a rise in fluconazole-resistant strains.
  • The findings suggest a concerning trend in antifungal resistance, highlighting the need for heightened awareness and improved infection control strategies in healthcare settings.
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  • The study investigated the pharmacodynamics of liposomal amphotericin B (L-AMB) against various species, as there is a lack of comparative pharmacokinetic/pharmacodynamic (PK/PD) studies in this area.
  • *The PK/PD model tested different concentrations of L-AMB and identified that a dose of 8 mg/L was effective against certain susceptible isolates, while higher doses (≥ 32 mg/L) were needed for resistant isolates.
  • *Results showed that a standard dose of 3 mg/kg is adequate for treating some species, while a higher dose of 5 mg/kg may be necessary for effective treatment against other, less susceptible species.*
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  • Candida auris cases in Greece rose significantly after 2019, leading to active surveillance from November 2019 to September 2021 in 11 hospitals, focusing on confirmed infections and outbreaks.
  • A study identified 20 invasive infections and 25 colonized cases, with high mortality (53%) and common risk factors such as the use of indwelling devices and previous antibiotic treatments.
  • The fungus showed resistance to fluconazole in all isolates and was mostly linked to a specific South Asian strain, highlighting the need for improved infection control measures in healthcare settings.
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From 2019 (pre-COVID-19) to 2022 (COVID-19 years), three tertiary Greek hospitals monitored MDRO bloodstream infection (BSI) and hospital acquisition relying on laboratory data. Surveillance covered carbapenem-resistant Enterobacterales (CRE), Acinetobacter baumannii (CRAB), Pseudomonas aeruginosa (CRPA), vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA), in intensive care units (ICUs) and non-ICUs. Non-ICUs experienced significant increases in CRE, CRAB and VRE during the pandemic.

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Article Synopsis
  • * The Vitek 2 system showed poor agreement for certain antifungals like 5-flucytosine, fluconazole, and amphotericin B, but achieved moderate to high agreement for echinocandin drugs like micafungin and caspofungin.
  • * Resistance was often misclassified, with the Vitek 2 underestimating fluconazole resistance and overestimating amphotericin B resistance, though using specific Vitek 2 values improved agreement rates
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Objectives: A multicentre study evaluating NG-Test DetecTool OXA-23 for the detection of OXA-23 carbapenemase directly from positive blood cultures (PBCs).

Methods: The NG-Test DetecTool OXA-23 is an immunoassay that integrates a sample preparation device. We evaluated NG-Test DetecTool OXA-23 on 189 spiked and 126 clinical PBCs.

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Scope: Pseudomonas aeruginosa, a ubiquitous opportunistic pathogen considered one of the paradigms of antimicrobial resistance, is among the main causes of hospital-acquired and chronic infections associated with significant morbidity and mortality. This growing threat results from the extraordinary capacity of P. aeruginosa to develop antimicrobial resistance through chromosomal mutations, the increasing prevalence of transferable resistance determinants (such as the carbapenemases and the extended-spectrum β-lactamases), and the global expansion of epidemic lineages.

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  • Carbapenem-resistant Acinetobacter baumannii (CRAB) infections pose a serious treatment challenge due to limited options, but new drugs like cefiderocol and sulbactam-durlobactam offer hope.
  • The review evaluates how these drugs work, their resistance mechanisms, and their effectiveness against CRAB, showing they both show excellent antimicrobial activity.
  • Cefiderocol has comparable efficacy to existing treatments like colistin, with fewer safety concerns, while sulbactam-durlobactam appears particularly useful for critically ill patients when other antibiotics fail.
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Article Synopsis
  • Candida auris isolates show higher resistance to amphotericin B (AMB), prompting research into the effectiveness of liposomal AMB (L-AMB) against these isolates.
  • An in vitro study tested four C. auris isolates using a pharmacokinetic/pharmacodynamic (PK/PD) model, revealing that L-AMB's effectiveness is dose-dependent, with higher doses needed for resistant strains.
  • Results indicated that L-AMB was significantly less effective against C. auris compared to C. albicans, necessitating higher doses for treatment of more resistant C. auris strains.
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Article Synopsis
  • Research showed that current PK/PD targets for echinocandins do not align with clinical breakpoints for Candida parapsilosis, despite their effective treatment results.
  • An in vitro study investigated micafungin's effects against various C. parapsilosis isolates in conditions simulating human serum, revealing low probabilities of target attainment (PTA) for susceptible strains.
  • A new PK/PD target was identified that enhances the understanding of micafungin’s efficacy and could aid in evaluating treatment strategies for C. parapsilosis infections.
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In this study, we aimed to determine the antibiotic resistance status of spp. isolated from human infections in our region, including the role of mechanisms involved in erythromycin resistance. Standard methods were used for the isolation, identification and antibiotic susceptibility testing of spp.

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Article Synopsis
  • * Researchers tested 10 wild-type and 4 non-wild-type Aspergillus fumigatus isolates with varying inocula (102-105 cfu/mL) and evaluated the MEC through several methods, finding better agreement and clearer results with lower inocula (102 and 103 cfu/mL).
  • * Results indicated that using a 103 cfu/mL inoculum for 48 hours led to improved reliability in MEC determination and suggested that a colorimet
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Objectives: B-cell depleting monoclonal antibodies are associated with increased COVID-19 severity and impaired immune response to vaccination. We aimed to assess the humoral and cell mediated (CMI) immune response after SARS-CoV-2 vaccination in rituximab (RTX)-treated rheumatic patients.

Methods: Serum and whole blood samples were collected from RTX-treated rheumatic patients 3-6 months after last vaccination against SARS-CoV-2.

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Diagnostic tools that can rapidly identify and characterize microbes growing in blood cultures are important components of clinical microbiology practice because they help to provide timely information that can be used to optimize patient management. This publication describes the bioMérieux BIOFIRE Blood Culture Identification 2 (BCID2) Panel clinical study that was submitted to the U.S.

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  • The study aimed to correlate in vitro tests of posaconazole (POS) and amphotericin B (AMB) with in vivo treatment outcomes in a mouse model of candidiasis, exploring the effectiveness of the drug combination.* -
  • In vitro results showed both synergistic and antagonistic interactions depending on the drug concentrations, with synergy observed at low doses and antagonism at higher doses.* -
  • In vivo findings further confirmed these interactions, illustrating how POS could enhance the effects of low AMB doses while diminishing the efficacy of high AMB doses, indicating a complex relationship between drug concentrations and treatment outcomes.*
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Significant variation in minimal inhibitory concentrations (MIC) has been reported for amphotericin B (AMB) and C. auris, depending on the antifungal susceptibility testing (AFST) method. Although the Sensititre YeastOne (SYO) is widely used in routine laboratory testing, data regarding its performance for the AFST of C.

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In the light of increasing antimicrobial resistance among gram-negative bacteria and the lack of new more potent antimicrobial agents, new strategies have been explored. Old antibiotics, such as colistin, temocillin, fosfomycin, mecillinam, nitrofurantoin, minocycline, and chloramphenicol, have attracted the attention since they often exhibit in vitro activity against multi-drug-resistant (MDR) gram-negative bacteria, such as Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. The current review provides a summary of the in vitro activity, pharmacokinetics and PK/PD characteristics of old antibiotics.

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Aspergillus spp. isolated from non-BAL cultures of coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) patients may reflect colonization rather than infection. Sera (n = 181) from 49 adult ICU CAPA patients (24 probable and 25 possible CAPA) with bronchial secretions (BS) culture positive for Aspergillus spp.

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The presence of heteroresistant subpopulations and the development of resistance during drug exposure (adaptive resistance) limits colistin's efficacy against carbapenemase-producing (CP-Kp) isolates.. The pharmacokinetic/pharmacodynamic (PK/PD) characteristics of both types of colistin resistance against CP-Kp are unknown.

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The isolation of a pan-echinocandin-resistant Candida parapsilosis strain (anidulafungin, caspofungin, micafungin and rezafungin EUCAST MICs > 8 mg/L) from urine of a patient following prolonged exposure to echinocandins (38 days of micafungin followed by 16 days of anidulafungin) is described. The isolate harbored the novel alteration F652S in the hotspot 1 region of fks1. Isogenic C.

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