Eliane Siebor

Epidemiology and resistance of Achromobacter xylosoxidans from cystic fibrosis patients in Dijon, Burgundy: First French data

BACKGROUND Achromobacter xylosoxidans is an emerging pathogen in cystic fibrosis (CF) patients recognised as causal agent of inflammation. The prevalence of infection or colonisation is variable among CF centres. We report here the first epidemiological data about A. xylosoxidans in a French CF centre: Dijon, Burgundy. METHODS All isolates recovered from the patients affiliated with our centre in 2010 since their first visit were included. Antimicrobial susceptibility was determined by disk diffusion method and E-test. Molecular epidemiology was performed by Pulsed Field Gel Electrophoresis (PFGE) and compared with repetitive sequence-based PCR (rep-PCR, DiversiLab®). We also sequenced the constitutive bla-oxa-114 gene. RESULTS Out of 120 patients, 21 (17.5%) had at least one positive culture with A. xylosoxidans since they started to receive routine care in our CF centre (447 isolates). Median age at first positive culture was 16 years (range 3-34 years). Most patients were colonised by their own strain, cross-contamination was very rare. We observed two cases of intra-family spread. DiversiLab® is a useful tool as efficient as PFGE to compare isolates recovered simultaneously from different patients when an outbreak is suspected. However, PFGE remains the reference method for long-term survey of chronically colonised patients. We detected new OXA-114 variants and the new oxacillinase OXA-243 (88% amino acid identity with OXA-114). Acquired resistance to ciprofloxacin, ceftazidime and carbapenems was frequent. In 2010, 7 patients harboured strains resistant to ceftazidime, 6 patients strains with decreased susceptibility to carbapenems (especially meropenem) and 12 patients strains resistant to ciprofloxacin. CONCLUSIONS In our centre, the high prevalence of colonisation is not due to cross-contamination. Our main concern is the high rate of antimicrobial resistance.

First Description of an RND-Type Multidrug Efflux Pump in Achromobacter xylosoxidans, AxyABM

ABSTRACT Achromobacter xylosoxidans is an emerging pathogen in cystic fibrosis patients. The multidrug resistance of these bacteria remains poorly understood. We have characterized in a clinical strain the first resistance-nodulation-cell division (RND)-type multidrug efflux pump in this species: AxyABM. The inactivation of the transporter component axyB gene led to decreased MICs of cephalosporins (except cefepime), aztreonam, nalidixic acid, fluoroquinolones, and chloramphenicol.

First Occurrence of an IMP Metallo-β-Lactamase in Aeromonas caviae: IMP-19 in an Isolate from France

ABSTRACT We describe the first IMP metallo-β-lactamase in Aeromonas caviae: IMP-19, which differed from IMP-2 by a single amino acid change (Arg to Ala at position 38). blaIMP-19 was found within a class 1 integron located on a 35-kb plasmid. This is also the first description of an IMP producer in France.

Emergence of Salmonella genomic island 1 (SGI1) among Proteus mirabilis clinical isolates in Dijon, France

OBJECTIVES Salmonella genomic island 1 (SGI1) is often encountered in antibiotic-resistant Salmonella enterica and exceptionally in Proteus mirabilis. We investigated the prevalence of SGI1-producing clinical isolates of P. mirabilis in our hospital (Dijon, France). METHODS A total of 57 strains of P. mirabilis resistant to amoxicillin and/or gentamicin and/or trimethoprim/sulfamethoxazole isolated from August 2011 to February 2012 as well as 9 extended-spectrum β-lactamase (ESBL)-producing P. mirabilis from our collection were tested for the presence of SGI1 by PCR. The complete SGI1 structure from positive isolates [backbone and multidrug resistance (MDR) region] was sequenced. RESULTS SGI1 was detected in 7 isolates; 5 out of the 57 isolates collected during the study period (9%) and 2 out of the 9 ESBL-producing strains of our collection. The structures of the seven SGI1s were distinct. Three different backbones were identified: one identical to the SGI1 backbone from the epidemic Salmonella Typhimurium DT104, one with variations already described in SGI1-K from Salmonella Kentucky (deletion and insertion of IS1359 in the region spanning from S005 to S009) and one with a variation never detected before (deletion from S005 to S009). Six different MDR regions were identified: four simple variants containing resistance genes already described and two variants harbouring a very complex structure including regions derived from several transposons and IS26 elements with aphA1a never reported to date in SGI1. CONCLUSIONS SGI1 variants are widely distributed among P. mirabilis clinical strains and might spread to other commensal Enterobacteriaceae. This would become a serious public health problem.

TEM-89 β-Lactamase Produced by a Proteus mirabilis Clinical Isolate: New Complex Mutant (CMT 3) with Mutations in both TEM-59 (IRT-17) and TEM-3

ABSTRACT TEM-89 (CMT-3) is the first complex mutant β-lactamase produced by a clinical strain of Proteus mirabilis (strain Pm 631). This new enzyme, which has a pI of 6.28, is derived from TEM-3 and has a single amino acid substitution also encountered in TEM-59 (inhibitor-resistant TEM β-lactamase IRT-17): Ser-130 to Gly. TEM-89 hydrolyzed penicillins to the same extent that TEM-3 did but lost almost all hydrolytic activity for cephalosporins and, like TEM-59, was highly resistant to inhibitors.

EVIDENCE OF IN VIVO TRANSFER OF A PLASMID ENCODING THE EXTENDED-SPECTRUM BETA-LACTAMASE TEM-24 AND OTHER RESISTANCE FACTORS AMONG DIFFERENT MEMBERS OF THE FAMILY ENTEROBACTERIACEAE

ABSTRACT The epidemiological study of several multidrug-resistantEnterobacteriaceae isolated from five patients demonstrated in vivo dissemination of a 100-kb plasmid encoding the extended-spectrum β-lactamase TEM-24 from a clonal strain ofEnterobacter aerogenes to different strains ofKlebsiella pneumoniae, Escherichia coli, Proteus vulgaris, Proteus mirabilis, and Serratia marcescens.

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.

Survey of Enterobacteriaceae Producing Extended-Spectrum β-Lactamases in a Slovak Hospital: Dominance of SHV-2a and Characterization of TEM-132

ABSTRACT Eighty-five extended-spectrum β-lactamase-producing Enterobacteriaceae from a Slovak hospital have been studied. SHV-2a was predominant, but other variants have been detected, namely, SHV-5, SHV-12, TEM-12, TEM-15, and TEM-132, which differed from TEM-1 by amino acid substitutions R164H, E240K, and I173V and had kinetic properties similar to those of TEM-28.

Survey of multidrug resistance integrative mobilizable elements SGI1 and PGI1 in Proteus mirabilis in humans and dogs in France, 2010–13

OBJECTIVES To characterize MDR genomic islands related to Salmonella genomic island 1 (SGI1) and Proteus genomic island 1 (PGI1) in Proteus mirabilis from human and animal sources in France in light of the previously reported cases. METHODS A total of 52 and 46 P. mirabilis clinical strains from human and animal sources, respectively, were studied for the period 2010-13. MDR was assessed by antimicrobial susceptibility testing, PCR detection of SGI1 and PGI1 and PCR mapping of the MDR regions. The diversity of the SGI1/PGI1-positive P. mirabilis strains was assessed by PFGE. RESULTS Twelve P. mirabilis strains (5 humans and 7 dogs) were found to harbour an MDR island related to SGI1 or PGI1. Among them, several SGI1 variants were identified in diverse P. mirabilis genetic backgrounds. The variant SGI1-V, which harbours the ESBL bla VEB-6 gene, was found in closely genetically related human and dog P. mirabilis strains. The recently described PGI1 element was also identified in human and dog strains. Finally, one strain harboured a novel SGI genomic island closely related to SGI1 and SGI2 without an insertion of the MDR region. CONCLUSION This study reports for the first time, to our knowledge, SGI1-positive and PGI1-positive P. mirabilis strains from dogs in France. The genetic diversity of the strains suggests several independent horizontal acquisitions of these MDR elements. The potential transmission of SGI1/PGI1-positive P. mirabilis strains between animals and humans is of public health concern, notably with regard to the spread of ESBL and carbapenemase genes, i.e. bla VEB-6 and bla NDM-1.

Characterization of TEM-56, a Novel β-Lactamase Produced by a Klebsiella pneumoniae Clinical Isolate

ABSTRACT TEM-56 produced by a Klebsiella pneumoniae clinical isolate is a novel β-lactamase of isoelectric point 6.4 that confers a moderate resistance level to expanded-spectrum cephalosporins. The amino acid sequence deduced from the corresponding bla gene showed two amino acid replacements with respect to the TEM-2 sequence: Glu-104 to Lys and His-153 to Arg. This enzyme showed catalytic properties close to those of TEM-18. Thus, TEM-56 appears as a new TEM mutant, an intermediary between TEM-18 and the extended-spectrum β-lactamase TEM-21.