0000000001275389
AUTHOR
Catherine Neuwirth
Development of a database for the rapid and accurate routine identification of Achromobacter species by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS).
International audience; Objectives: Achromobacter spp. are emerging pathogens in respiratory samples from cystic fibrosis patients. The current reference methods (nrdA-sequencing or multilocus sequence typing) can identify 18 species which are often misidentified by conventional techniques as A. xylosoxidans. A few studies have suggested that matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF/MS) provides accurate identification of the genus but not of species. The aims of this study were (a) to generate a database for MALDI-TOF/MS Bruker including the 18 species, (b) to evaluate the suitability of the database for routine laboratory identification, and …
Relation trophique et prévalence de gènes de résistances aux antibiotiques dans les communautés bactériennes de poissons
National audience
Détection de sources animales et environnementales de souches d’E. coli productrices de betalactamases à spectre élargi (BLSE) à l’échelle d’une région française (Bourgogne)
National audience
Role of AxyZ Transcriptional Regulator in Overproduction of AxyXY-OprZ Multidrug Efflux System in Achromobacter Species Mutants Selected by Tobramycin
ABSTRACT AxyXY-OprZ is an RND-type efflux system that confers innate aminoglycoside resistance to Achromobacter spp. We investigated here a putative TetR family transcriptional regulator encoded by the axyZ gene located upstream of axyXY-oprZ . An in-frame axyZ gene deletion assay led to increased MICs of antibiotic substrates of the efflux system, including aminoglycosides, cefepime, fluoroquinolones, tetracyclines, and erythromycin, indicating that the product of axyZ negatively regulates expression of axyXY-oprZ . Moreover, we identified an amino acid substitution at position 29 of AxyZ (V29G) in a clinical Achromobacter strain that occurred during the course of chronic respiratory tract…
Two new Salmonella genomic islands 1 from Proteus mirabilis and description of blaCTX-M-15 on a variant (SGI1-K7)
Objectives To characterize the structure of Salmonella genomic islands 1 (SGI1s) from two clinical Proteus mirabilis isolates: one producing an ESBL and the other a penicillinase. Methods WGS completed by PCR and Sanger sequencing was performed to determine sequences of SGI1s from Pm2CHAMA and Pm37THOMI strains. Results Two new variants of SGI1 named SGI1-Pm2CHAMA (53.6 kb) and SGI1-K7 (55.1 kb) were identified. The backbone of SGI1-Pm2CHAMA shared 99.9% identity with that of SGI1. Its MDR region (26.3 kb) harboured two class 1 integrons (an In2-type integron and an In4-type integron) containing in particular a qacH cassette (encoding a quaternary ammonium compound efflux pump). These two i…
Occurrence of CTX-M Producing Escherichia coli in Soils, Cattle, and Farm Environment in France (Burgundy Region).
Article en open access; International audience; CTX-M [a major type of extended-spectrum beta-lactamase (ESBU] producing Escherichia coli are increasingly involved in human infections worldwide. The aim of this study was to investigate potential reservoirs for such strains: soils, cattle, and farm environment. The prevalence of bla(CTX-M) genes was determined directly from soil DNA extracts obtained from 120 sites in Burgundy (France) using real-time PCR. bla(CTX-M) targets were found in 20% of the DNA extracts tested. Samples of cattle feces (n = 271) were collected from 182 farms in Burgundy. Thirteen ESBL-producing isolates were obtained from 12 farms and further characterized for the pr…
Successful control of a Methicillin-resistant Staphylococcus aureus outbreak in a neonatal intensive care unit: a retrospective, before-after study
International audience; Background : Aim of this study was to provide a detailed description of a Methicillin-resistant Staphylococcus aureus (MRSA) outbreak management strategy in the neonatal intensive care unit of a university hospital.MethodsThis was a retrospective, “before-after” study, over two consecutive 18-month periods. The outbreak management strategy was performed by a multidisciplinary team and included: extensive healthcare workers (HCW) involvement, education, continuous hand-hygiene training and active MRSA colonization surveillance. The actions implemented were identified based on an anonymous, voluntary, reporting system, carried out among all the HCW, and regular audit a…
Factors associated with 12 week case-fatality in Staphylococcus aureus bacteraemia: a prospective cohort study
International audience; Staphylococcus aureus bacteraemia (SAB) is a frequent and deadly disease. Given the lack of a randomized trial, optimal first-line antibiotic treatment is still debated. Our aim was to identify prognostic factors in SAB patients and to analyse the impact of first-line antibiotics. The VIRSTA prospective cohort study was conducted in eight tertiary care centres in France. Consecutive incident adults in whom a blood culture drawn in participating centres grew S. aureus between April 2009 and October 2011 were prospectively followed for 12 weeks. Factors associated with 12-week case-fatality were identified by multivariate logistic regression. We enrolled 2091 patients …
New insights regarding Acinetobacter genomic island-related elements
The objective of this study was to mobilize the Acinetobacter genomic island 1-A (AGI1-A) from Enterobacter hormaechei EclCSP2185 (E. cloacae complex) and to search for the distribution and structure of AGI1-related elements in the NCBI database. AGI1-A was transferred to Escherichia coli. Analysis of the attachment (att) sites could locate the possible recombination crossover in the att sequences at position 10-11 (GG) in the last 18 bp of trmE. In silico detection of AGI backbones in the wgs database identified AGI variants in Salmonella enterica (83 strains), Vibrio cholerae (33), E. hormaechei (12), Acinetobacter baumannii (2), most belonging to prevalent clones (ST40, ST69, ST114 and S…
Dissemination of CTX-M-Producing Escherichia coli in Freshwater Fishes From a French Watershed (Burgundy)
International audience; The burden of extended-spectrum beta-lactamases producing Escherichia coli (ESBL-Ec), has increased over several decades. Freshwater ecosystems are suspected to play an important ecological and evolutionary role in driving the dissemination of antimicrobial resistance. The aim of our study was to decipher the occurrence of ESBL-Ec in a small watershed (Ouche river, Burgundy, France), targeting environmental matrices and fishes. Among cefotaxime resistant E. coli (ctxR Ec) isolates, we detected and characterized 36 ESBL-Ec from water, biofilm and fish guts. ctxR Ec and ESBL-Ec were found in samples from sites near the first small town, located downstream from the wate…
Prevalence of CTX-M producing E. coli in cattle and soil environment in the Burgundy region
National audience
Mobilisation of plasmid-mediated blaVEB-1 gene cassette into distinct genomic islands of Proteus mirabilis after ceftazidime exposure
ABSTRACT Objectives We sought to integrate a VEB-1-encoding gene cassette into the integron of the MDR region of genomic islands (GIs) harboured by Proteus mirabilis strains after antibiotic exposure. Methods An IncP1 plasmid from Achromobacter xylosoxidans carrying the cassette array dfrA14–blaVEB-1–aadB was introduced by conjugation into five strains of P. mirabilis: PmBRI, PmABB, PmSCO and Pm2CHAMA harbouring Salmonella GI 1 and PmESC harbouring Proteus GI 1. Circular intermediates of the cassettes were amplified by PCR. blaVEB-harbouring P. mirabilis were exposed to increasing concentrations of ceftazidime each day. Presence of blaVEB-1 in the GI was assessed by PCR. The complete MDR re…
Amperometric detection of extended-spectrum β-lactamase activity : application to the characterization of resistant E.coli strains
EA MERS CT3; International audience; The amperometric detection of extended-spectrum β-lactamase (ESBL) with carbon screen-printed sensors was investigated in the presence of the Nitrocefin, a commercially-available β-lactamase chromogenic cephalosporin substrate. Using an ESBL isolated from a clinical sample, it was shown for the first time that the intensity of a specific anodic pic current (EP = [similar]+0.3 V vs. Ag/AgCl) resulting from the catalytic hydrolysis of the β-lactam ring was proportional to the amount of ESBL. The proof-of-principle of a novel susceptibility assay for the rapid and accurate identification of ESBL- producing bacteria was then demonstrated. The detection schem…
VEB-1 in Achromobacter xylosoxidans from Cystic Fibrosis Patient, France
Multidrug-resistant Achromobacter xylosoxidans was recovered from the sputum of a patient with cystic fibrosis. The VEB-1 extended-spectrum β-lactamase was detected on a class 1 integron. This first report of a VEB-1–producing isolate in this population requires further investigation to determine its distribution.
Détection et caractérisation moléculaire de souches d’Escherichia coli porteuses de gènes de résistance CTX-M (betalactamases à spectre élargi ou BLSE) et de gènes de virulence dans deux exploitations agricoles
National audience
Time to blood culture positivity: An independent predictor of infective endocarditis and mortality in patients with Staphylococcus aureus bacteraemia
International audience; Objectives - Time to blood culture positivity (TTP), a routinely available parameter in automated blood culture systems, may be a proxy for infectious burden in patients with bloodstream infections. We aimed to study the association between TTP and infective endocarditis (IE), or death, in patients with Staphylococcus aureus bacteraemia. Methods - VIRSTA is a multicenter prospective cohort study that included all adult patients with S. aureus bacteraemia in eight university hospitals in France (2009-2011). We analyzed data from four centers which collected data on TTP. Regression models were used to study the association between TTP and definite IE (Duke-Li criteria)…
Evolving epidemiology and antimicrobial resistance in spontaneous bacterial peritonitis: a two-year observational study.
Background Current recommendations for empirical antimicrobial therapy in spontaneous bacterial peritonitis (SBP) are based on quite old trials. Since microbial epidemiology and the management of patients have changed, whether these recommendations are still appropriate must be confirmed. Methods An observational study that exhaustively collected the clinical and biological data associated with positive ascitic fluid cultures was conducted in four French university hospitals in 2010–2011. Results Two hundred and sixty-eight documented positive cultures were observed in 190 cirrhotic patients (median age 61.5 years, 58.5% Child score C). Of these, 57 were classified as confirmed SBP and 140 …