Search results for "beta-Lactamases"

Is the monoclonal spread of the ST258, KPC-3-producing clone being replaced in southern Italy by the dissemination of multiple clones of carbapenem-n…

2015

D. M. Geraci, C. Bonura, M. Giuffre, L. Saporito, G. Graziano, A. Aleo, T. Fasciana, F. Di Bernardo, T. Stampone, D. M. Palma and C. Mammina 1) Department of Sciences for Health Promotion and Mother-Child Care ‘G. D’Alessandro’, University of Palermo, 2) Postgraduate Specialty School in Hygiene and Preventive Medicine, University of Palermo, 3) Laboratory of Microbiology, General Hospital ARNAS ‘Civico, Di Cristina & Benfratelli’, 4) Laboratory of Microbiology, General Hospital Azienda Ospedaliera ‘Villa Sofia-V, Cervello’ and 5) II Intensive Care Unit, General Hospital ARNAS ‘Civico, Di Cristina & Benfratelli’, Palermo, Italy

Influence of Haemophilus influenzae β-lactamase production and/or ftsI gene mutations on in vitro activity of and susceptibility rates to aminopenici…

2007

Multidrug and broad-spectrum cephalosporin resistance among Salmonella enterica serotype enteritidis clinical isolates in southern Italy.

2002

ABSTRACT From 1992 to 1997, only six sporadic isolates of Salmonella enterica serotype Enteritidis from patients with cases of gastroenteritis in southern Italy exhibited resistance to broad-spectrum cephalosporins. Five isolates produced SHV-12, and one isolate encoded a class C β-lactamase. The bla SHV-12 gene was located in at least two different self-transferable plasmids, one of which also carried a novel class 1 integron.

Multiclonal emergence of carbapenem-resistant Klebsiella pneumoniae in Tuscany, Italy

2010

Populations of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae are different in human-polluted environment and foo…

2021

Abstract Objectives To assess the extent to which food items are a source of extended-spectrum β-lactamase (ESBL) -producing Escherichia coli (ESBL-Ec) and ESBL-producing Klebsiella pneumoniae (ESBL-Kp) for humans in five European cities. Methods We sampled 122 human polluted (hp)-environments (sewers and polluted rivers, as a proxy of human contamination) and 714 food items in Besancon (France), Geneva (Switzerland), Sevilla (Spain), Tubingen (Germany) and Utrecht (The Netherlands). A total of 254 ESBL-Ec and 39 ESBL-Kp isolates were cultured. All genomes were fully sequenced to compare their sequence types (ST) and core genomes, along with the distribution of blaESBL genes and their genet…

Targeting the Class A Carbapenemase GES-5 via Virtual Screening

2020

The worldwide spread of &beta

Role of Protein Flexibility in Enzymatic Catalysis:  Quantum Mechanical−Molecular Mechanical Study of the Deacylation Reaction in Class A β-Lactamases

2002

We present a theoretical study of a mechanism for the hydrolysis of the acyl-enzyme complex formed by a class A beta-lactamase (TEM1) and an antibiotic (penicillanate), as a part of the process of antibiotic's inactivation by this type of enzymes. In the presented mechanism the carboxylate group of a particular residue (Glu166) activates a water molecule, accepting one of its protons, and afterward transfers this proton directly to the acylated serine residue (Ser70). In our study we employed a quantum mechanics (AM1)-molecular mechanics partition scheme (QM/MM) where all the atoms of the system were allowed to relax. For this purpose we used the GRACE procedure in which part of the system …

Computational study on hydrolysis of cefotaxime in gas phase and in aqueous solution

2012

We are presenting a theoretical study of the hydrolysis of a β-lactam antibiotic in gas phase and in aqueous solution by means of hybrid quantum mechanics/molecular mechanics potentials. After exploring the potential energy surfaces at semiempirical and density functional theory (DFT) level, potentials of mean force have been computed for the reaction in solution with hybrid PM3/TIP3P calculations and corrections with the B3LYP and M06-2X functionals. Inclusion of the full molecule of the antibiotic, Cefotaxime, in the gas phase molecular model has been demonstrated to be crucial since its carboxylate group can activate a nucleophilic water molecule. Moreover, the flexibility of the substra…

An international perspective on hospitalized patients with viral community-acquired pneumonia

2019

Background Who should be tested for viruses in patients with community acquired pneumonia (CAP), prevalence and risk factors for viral CAP are still debated. We evaluated the frequency of viral testing, virus prevalence, risk factors and treatment coverage with oseltamivir in patients admitted for CAP. Methods Secondary analysis of GLIMP, an international, multicenter, point-prevalence study of hospitalized adults with CAP. Testing frequency, prevalence of viral CAP and treatment with oseltamivir were assessed among patients who underwent a viral swab. Univariate and multivariate analysis was used to evaluate risk factors. Results 553 (14.9%) patients with CAP underwent nasal swab. Viral CA…

Characterization of the first extended-spectrum beta-lactamase-producing nontyphoidal Salmonella strains isolated in Tehran, Iran.

2009

The infections caused by Salmonella remain a significant public health problem throughout the world. beta-Lactams and fluoroquinolones are generally used to treat invasive Salmonella infections, but emergence and spread of antibiotic-resistant strains are being increasingly notified in many countries. In particular, detection of extended-spectrum beta-lactamases (ESBLs) in Salmonella spp. is a newly emerging threat worldwide. This study was carried out to characterize beta-lactamase-producing Salmonella strains identified in Tehran, Iran. Over the 2-year period from 2007 to 2008, 6 of 136 Salmonella isolates recovered from pediatrics patients, including three Salmonella enterica serotypes E…