Publications by authors named "Silvia D'Arezzo"

: Enterococci, particularly and , are Gram-positive cocci that can cause severe infections in hospitalized patients. The rise of vancomycin-resistant enterococci (VRE) and vancomycin-variable enterococci (VVE) poses significant challenges in healthcare settings due to their resistance to multiple antibiotics. : We conducted a point prevalence survey (PPS) to assess the prevalence of VRE and VVE colonization in hospitalized patients.

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Between December 2023 and February 2025, six cases of malaria were reported in travellers returning to Italy from Zanzibar, a popular tourist destination often perceived as low risk. None had taken prophylaxis, five had severe malaria and two died. Diagnostic delays revealed a lack of clinical suspicion of malaria and awareness among travellers and healthcare professionals.

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: Vancomycin-resistant enterococci (VRE) rectal colonization represents a critical risk factor for subsequent bloodstream infections (BSIs), posing a serious concern in healthcare settings. This study aims to investigate the association between the presence of VRE in rectal swabs and the occurrence of BSIs, highlighting the challenges of rapid detection and patient care implications in an infectious disease hospital setting. : We performed a retrospective analysis of cultural rectal swab screening and molecular assays (MAs) for VRE detection between January 2020 and December 2023.

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: Multi-drug-resistant Gram-negative bacteria producing metallo-β-lactamase are an increasing concern. Here, we described three cases of infection due to difficult-to-treat and drug-resistant producing metallo-β-lactamases, which were successfully treated with antibiotic combination of cefiderocol plus imipenem-relebactam, and reported on the molecular and epidemiological features of the isolates and the in vitro synergistic effects of different antibiotic combinations guiding antibiotic treatment. : Three strains were isolated from respiratory or blood cultures of three different patients.

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Background/objectives: Antimicrobial resistance represents a challenge to public health systems because of the array of resistance and virulence mechanisms that lead to treatment failure and increased mortality rates. Although for years the main driver of carbapenem resistance in Italy has been the KPC carbapenemase, recent years have seen an increase in VIM and NDM metallo-beta-lactamases (MBLs). We conducted a five-year survey of New Delhi Metallo-beta-Lactamase (NDM)-producing (NDM-Kpn) clinical isolates from the Lazio region, Italy; the study aimed to elucidate the molecular mechanisms underpinning their resistant and virulent phenotype.

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strains that are resistant to multiple drugs (KPMDRs), which are often acquired in hospital settings and lead to healthcare-associated infections, pose a serious public health threat, as does hypervirulent (hvKp), which can also cause serious infections in otherwise healthy individuals. The widespread and often unnecessary use of antibiotics seen during the recent COVID-19 pandemic has exacerbated the challenges posed by antibiotic resistance in clinical settings. There is growing concern that hypervirulent (hvKp) strains may acquire genes that confer antimicrobial resistance, thus combining an MDR profile with their increased ability to spread to multiple body sites, causing difficult-to-treat infections.

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Neisseria meningitidis represents an uncommon pathogen of acute bacterial conjunctivitis. In this brief report, we describe a case of meningococcal conjunctivitis in an immunocompetent adult male, with a review of the literature. The patient went to the outpatient ophthalmology clinic complaining of severe ocular discomfort, burning, and redness for more than 2 weeks and, at slit lamp examination, he was diagnosed with a mild conjunctivitis.

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Equine pulmonary aspergillosis is a rare deep mycosis often due to the hematogenous spread of hyphae after gastrointestinal tract disease. We describe herein the main clinic-pathological findings observed in a foal, which spontaneously died after showing diarrhea and respiratory distress. Necropsy and histopathological investigations allowed to diagnose pulmonary aspergillosis, which likely developed after necrotic typhlitis-colitis.

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Objectives: Clostridioides difficile infection (CDI) represents a challenging issue, with an evolving epidemiology. Main objectives of our study were: to assess the frequency of diarrhea of overall etiology, including CDI, as a cause of hospital admission or occurring during hospital stay;- to determine the rate of underdiagnosis of community-acquired (CA-), health care associated (HCA)- and hospital onset (HO-) CDI, and explore factors associated with its clinical suspicion by physicians.

Methods: A prospective cohort study included all hospitalized patients with diarrhea at two acute-care hospitals.

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Objectives: To analyse the strains collected during a 1-year survey of ceftazidime-avibactam-resistant KPC-producing Klebsiella pneumoniae, in order to investigate the molecular mechanisms potentially responsible for their resistant phenotype.

Methods: Clinical KPC-producing K. pneumoniae isolates were collected from 31 patients in six different hospitals in Rome.

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For years, carbapenemase (KPC)-producing have represented a serious health problem in hospitals worldwide. Since its approval in 2015, ceftazidime-avibactam (CAZ-AVI) had been successfully used for treating complicated KPC-K. infections, until increasing reports of resistance began to emerge.

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On 31 August, a veterinarian and a farmworker were hospitalised for skin lesions. Both had been exposed to a dead cow on 19 August on a farm near Rome, where eight further cattle died of confirmed anthrax later the same month. At admission, the first case showed a black depressed eschar and another smaller lesion on one hand.

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Objectives: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a serious nosocomial pathogen that causes a variety of serious, often life-threatening, infections and outbreaks. This study aimed to investigate the molecular epidemiology of clinical CRAB isolates from an outbreak that occurred in the intensive care unit (ICU) of an Italian hospital.

Methods: From December 2016 to April 2017, 13 CRAB isolates were collected from seven patients treated in the ICU at 'L.

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Colonizations due to carbapenem-resistant (CRE) are a source of antimicrobial resistance transmission in health care settings. Eleven strains producing KPC-3 carbapenemase were isolated from rectal swabs during a 3-year surveillance program. -carrying plasmids were found to belong to the IncX3 group in 9 of the 11 strains, and complete nucleotide sequences were obtained for 2 of them.

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In an era of increasing drug resistance and limited numbers of antimicrobials in the drug production pipeline, healthcare-associated infections represent a growing public health threat. When therapeutic options are limited, clinicians often resort to using antimicrobial combinations that produce a synergistic effect on the target pathogen. Novel antibiotics are therefore welcome in the daily practice of medicine.

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We describe the interspecies transmission of the plasmid-mediated blaKPC-3 gene, which confers carbapenem resistance, between clinically relevant gram-negative bacteria in a single patient. A KPC-3 producing Enterobacter aerogenes was isolated from a hospitalized patient previously colonized and then infected by a Klebsiella pneumoniae ST101 carrying the blaKPC-3 gene. The strains showed identical plasmids.

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We recently identified a novel family of macrocyclic amidinoureas showing potent antifungal activity against Candida spp. In this study, we demonstrate the fungicidal effect of these compounds as well as their killing activity in a dose-dependent manner. Transcriptional analysis data indicate that our molecules induce a significant change in the transcriptome involving ATP binding cassette (ABC) transporter genes.

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Background: HIV infection is a risk factor for Clostridium difficile infection (CDI) yet the immune deficiency predisposing to CDI is not well understood, despite an increasing incidence of CDI among such individuals. We aimed to estimate the incidence and to evaluate the risk factors of CDI among an HIV cohort in Italy.

Methods: We conducted a retrospective case-control (1:2) study.

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Aims: The aim of this study was to evaluate the in vitro activity of doripenem (DOR) alone and in combination with a variety of commonly used anti-Acinetobacter chemotherapeutic agents against 22 primary multidrug-resistant (MDR) Acinetobacter baumannii isolates (including 17 isolates that were resistant to DOR) from Intensive Care Unit patients. Antibiotic interactions were evaluated using the chequerboard method and the time-kill assay.

Results: Considering all antimicrobials in combination with DOR, chequerboard analysis showed synergy in 13 A.

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Article Synopsis
  • Pseudomonas aeruginosa poses a significant risk to immunocompromised patients, as shown by a fatal outbreak linked to a contaminated triclosan disinfectant.
  • The study found that the epidemic strain of P. aeruginosa was highly resistant to triclosan but susceptible to chlorhexidine digluconate, and exposure to triclosan increased the strain’s resistance to various antibiotics.
  • The findings suggest that using triclosan-based disinfectants in healthcare settings should be avoided to prevent further complications with antibiotic-resistant infections.
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Candida albicans is among the major agents of mucous membrane mycosis in humans and animals, with systemic and deep infections observed in immunocompromised hosts. We describe a case of fatal granulomatous myocarditis caused by C albicans in a 20-day-old canary (Serinus canaria). The etiologic diagnosis was confirmed by identifying characteristic morphologic features of the organism, combined with histochemical staining, and followed by the use of ad hoc biomolecular analysis.

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Carbapenem-resistant Acinetobacter baumannii strains belonging to international clonal lineage II (ICL-II) have become predominant in intensive care units (ICUs) throughout Italy. Between 2005 and 2009, the carbapenem-hydrolyzing class D β-lactamase (CHDL) bla(OXA-23) gene became more prevalent than bla(OXA-58) among epidemic ICL-II strains showing extensive genetic similarity. These findings posed the question of whether CHDL gene replacement occurred in the homogeneous ICL-II population or a new OXA-23 clone(s) emerged and spread in ICUs.

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The population structure of the species Legionella pneumophila was investigated by multilocus variable number of tandem repeats (VNTR) analysis (MLVA) and sequencing of three VNTRs (Lpms01, Lpms04 and Lpms13) in selected strains. Of 150 isolates of diverse origins, 136 (86 %) were distributed into eight large MLVA clonal complexes (VACCs) and the rest were either unique or formed small clusters of up to two MLVA genotypes. In spite of the lower degree of genome-wide linkage disequilibrium of the MLVA loci compared with sequence-based typing, the clustering achieved by the two methods was highly congruent.

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