Multicenter Retrospective Study of Vascular Infections and Endocarditis Caused by Campylobacter spp., France.

The incidence of campylobacteriosis has substantially increased over the past decade, notably in France. Secondary localizations complicating invasive infections are poorly described. We aimed to describe vascular infection or endocarditis caused by Campylobacter spp. We included 57 patients from a nationwide 5-year retrospective study on Campylobacter spp. bacteremia conducted in France; 44 patients had vascular infections, 12 had endocarditis, and 1 had both conditions. Campylobacter fetus was the most frequently involved species (83%). Antibiotic treatment involved a ß-lactam monotherapy (54%) or was combined with a fluoroquinolone or an aminoglycoside (44%). The mortality rate was 25%. Relapse occurred in 8% of cases and was associated with delayed initiation of an efficient antimicrobial therapy after the first symptoms, diabetes, and coexistence of an osteoarticular location. Cardiovascular Campylobacter spp. infections are associated with a high mortality rate. Systematically searching for those localizations in cases of C. fetus bacteremia may be warranted.

Retrospective Multicentric Study on Campylobacter spp. Bacteremia in France: The Campylobacteremia Study.

BACKGROUND: Campylobacter spp. bacteremia is a severe infection. A nationwide 5-year retrospective study was conducted to characterize its clinical features and prognostic factors. METHODS: The study included patients with Campylobacter spp. bacteremia diagnosed in 37 French hospitals participating in the surveillance network of the National Reference Center for Campylobacters and Helicobacters, from 1 January 2015 to 31 December 2019. The goal was to analyze the effects of a delay of appropriate antibiotic therapy and other risk factors on 30-day mortality rates, antibiotic resistance, patient characteristics, and prognosis according to the Campylobacter species. RESULTS: Among the 592 patients, Campylobacter jejuni and Campylobacter fetus were the most commonly identified species (in 42.9% and 42.6%, respectively). The patients were elderly (median age 68 years), and most had underlying conditions, mainly immunodepression (43.4%), hematologic cancers (25.9%), solid neoplasms (23%), and diabetes (22.3%). C. jejuni and Campylobacter coli were associated with gastrointestinal signs, and C. fetus was associated with secondary localizations. Among the 80 patients (13.5%) with secondary localizations, 12 had endocarditis, 38 vascular, 24 osteoarticular, and 9 ascitic fluid infections. The 30-day mortality rate was 11.7%, and an appropriate antibiotic treatment was independently associated with 30-day survival (odds ratio, 0.47 [95% confidence interval, .24-.93]; P = .03). The median efficient therapy initiation delay was quite short (2 days [interquartile range, 0-4 days]) but it had no significant impact on the 30-day mortality rate (P = .78). CONCLUSIONS: Campylobacter spp. bacteremia mainly occurred in elderly immunocompromised individuals with variable clinical presentations according to the species involved. Appropriate antimicrobial therapy was associated with improved 30-day survival.

Distribution of Achromobacter Species in 12 French Cystic Fibrosis Centers in 2020 by a Retrospective MALDI-TOF MS Spectrum Analysis.

Achromobacter spp. are nonfermenting Gram-negative bacilli mainly studied among cystic fibrosis (CF) patients. The identification of the 19 species within the genus is time-consuming (nrdA-sequencing), thus data concerning the distribution of the species are limited to specific studies. Recently, we built a database using MALDI-TOF mass spectrometry (MS) (Bruker) that allows rapid and accurate species identification and detection of the multiresistant epidemic clones: A. xylosoxidans ST137 spreading among CF patients in various French and Belgium centers, and A. ruhlandii DES in Denmark. Here, we first assessed whether species identification could be achieved with our database solely by analysis of MS spectra without availability of isolates. Then, we conducted a multicentric study describing the distribution of Achromobacter species and of the clone ST137 among French CF centers. We collected and analyzed with our local database the spectra of Achromobacter isolates from 193 patients (528 samples) from 12 centers during 2020. In total, our approach enabled to conclude for 502/528 samples (95.1%), corresponding to 181 patients. Eleven species were detected, only five being involved in chronic colonization, A. xylosoxidans (86.4%), A. insuavis (9.1%), A. mucicolens (2.3%), A. marplatensis (1.1%) and A. genogroup 3 (1.1%). This study confirmed the high prevalence of A. xylosoxidans in chronic colonizations and the circulation of the clone A. xylosoxidans ST137 in France: four patients in two centers. The present study is the first to report the distribution of Achromobacter species from CF patients samples using retrospective MALDI-TOF/MS data. This easy approach could enable future large-scale epidemiological studies.

Role of AxyABM overexpression in acquired resistance in Achromobacter xylosoxidans.

BACKGROUND: Acquired antimicrobial resistance among Achromobacter isolates from cystic fibrosis (CF) patients is frequent. Data concerning the mechanisms involved are scarce. The role of the AxyXY-OprZ and AxyEF-OprN Resistance Nodulation Division (RND) efflux systems has been demonstrated, but not that of AxyABM. OBJECTIVES: To explore the role of efflux systems in the acquired multiresistance observed in a one-step mutant selected after ofloxacin exposure. METHODS: The in vitro resistant mutant NCF-39-Bo2 and its parental strain NCF-39 (MICs of meropenem of 8 and 0.19 mg/L, of ceftazidime of 12 and 3 mg/L, of cefiderocol of 0.094 and 0.032 mg/L and of ciprofloxacin of 8 and 1.5 mg/L, respectively) were investigated by RNA-seq and WGS. Gene inactivation and reverse transcription quantitative PCR (RT-qPCR) were used to explore the role of the efflux systems of interest. RESULTS: RNA-seq showed that the AxyABM efflux system was overproduced (about 40-fold) in the in vitro mutant NCF-39-Bo2 versus its parental strain NCF-39. A substitution in AxyR, the putative regulator of AxyABM, was detected in NCF-39-Bo2. Gene inactivation of axyB (encoding the transporter component) in NCF-39-Bo2 led to a decrease in MICs of ciprofloxacin (5-fold), meropenem (64-fold), ceftazidime (12-fold) and cefiderocol (24-fold). Inactivation of axyB in the clinical isolate AXX-H2 harbouring a phenotype of resistance close to that of NCF-39-Bo2 enhanced the activity of the same molecules, especially meropenem. CONCLUSIONS: AxyABM overproduction is involved in acquired resistance of Achromobacter to ciprofloxacin, meropenem and ceftazidime, antibiotics widely used in CF patients, and increases the MIC of the new promising antibiotic cefiderocol.

What is the best technic to dislodge Staphylococcus epidermidis biofilm on medical implants?

BACKGROUND: Bacterial biofilm can occur on all medical implanted devices and lead to infection and/or dysfunction of the device. In this study, artificial biofilm was formed on four different medical implants (silicone, piccline, peripheral venous catheter and endotracheal tube) of interest for our daily clinical and/or research practice. We investigated the best conventional technic to dislodge the biofilm on the implants and quantified the number of bacteria. Staphylococcus epidermidis previously isolated from a breast implant capsular contracture on a patient in the university hospital of Dijon was selected for its ability to produce biofilm on the implants. Different technics (sonication, Digest-EUR®, mechanized bead mill, combination of sonication plus Digest-EUR®) were tested and compared to detach the biofilm before quantifying viable bacteria by colony counting. RESULTS: For all treatments, the optical and scanning electron microscope images showed substantial less biofilm biomass remaining on the silicone implant compared to non-treated implant. This study demonstrated that the US procedure was statistically superior to the other physical treatment: beads, Digest-EUR® alone and Digest-EUR® + US (p < 0.001) for the flexible materials (picc-line, PIV, and silicone). The number of bacteria released by the US is significantly higher with a difference of 1 log on each material. The result for a rigid endotracheal tube were different with superiority for the chemical treatment dithiothreitol: Digest-EUR®. Surprisingly the combination of the US plus Digest-EUR® treatment was consistently inferior for the four materials. CONCLUSIONS: Depending on the materials used, the biofilm dislodging technique must be adapted. The US procedure was the best technic to dislodge S. epidermidis biofilm on silicone, piccline, peripheral venous catheter but not endotracheal tube. This suggested that scientists should compare themselves different methods before designing a protocol of biofilm study on a given material.

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Rapid Detection of Isolates Belonging to the Epidemic Clones Achromobacter xylosoxidans ST137 and Achromobacter ruhlandii DES from Cystic Fibrosis Patients.

Achromobacter spp. are increasingly reported among cystic fibrosis patients. Genotyping requires time-consuming methods such as multilocus sequence typing or pulsed-field gel electrophoresis. Therefore, data on the prevalence of multiresistant epidemic clones, especially A. xylosoxidans ST137 (AxST137) and the Danish epidemic strain A. ruhlandii (DES), are lacking. We recently developed and published a database for Achromobacter species identification by matrix-assisted laser desorption-ionization-time of flight mass spectrometry (MALDI-TOF MS; Bruker Daltonics). The aim of this study was to evaluate the ability of the MALDI-TOF MS to distinguish these multiresistant epidemic clones within Achromobacter species. All the spectra of A. xylosoxidans (n = 1,571) and A. ruhlandii (n = 174) used to build the local database were analyzed by ClinProTools, MALDI Biotyper PCA, MALDI Biotyper dendrogram, and flexAnalysis software for biomarker peak detection. Two hundred two isolates (including 48 isolates of AxST137 and 7 of DES) were tested. Specific biomarker peaks were identified: absent peak at m/z 6,651 for AxST137 isolates and present peak at m/z 9,438 for DES isolates. All tested isolates were well typed by our local database and clustered within distinct groups (ST137 or non-ST137 and DES or non-DES) no matter the MALDI-TOF software or only by simple visual inspection of the spectra by any user. The use of MALDI-TOF MS allowed us to identify isolates of A. xylosoxidans belonging to the AxST137 clone that spread in France and Belgium (the Belgian epidemic clone) and of A. ruhlandii belonging to the DES clone. This tool will help the implementation of segregation measures to avoid interpatient transmission of these resistant clones.

Fluoroquinolone resistance in Achromobacter spp.: substitutions in QRDRs of GyrA, GyrB, ParC and ParE and implication of the RND efflux system AxyEF-OprN.

BACKGROUND: Achromobacter are emerging pathogens in cystic fibrosis patients. Mechanisms of resistance to fluoroquinolones are unknown in clinical isolates. Among non-fermenting Gram-negative bacilli, fluoroquinolone resistance is mostly due to amino acid substitutions in localized regions of the targets (GyrA, GyrB, ParC and ParE) named QRDRs, but also to efflux. OBJECTIVES: To explore quinolone resistance mechanisms in Achromobacter. METHODS: The putative QRDRs of GyrA, GyrB, ParC and ParE were sequenced in 62 clinical isolates, and in vitro one-step mutants obtained after exposure to fluoroquinolones. An in vitro mutant and its parental isolate were investigated by RNASeq and WGS. RT-qPCR and gene inactivation were used to explore the role of efflux systems overexpression. RESULTS: We detected seven substitutions in QRDRs (Q83L/S84P/D87N/D87G for GyrA, Q480P for GyrB, T395A/K525Q for ParE), all in nine of the 27 clinical isolates with ciprofloxacin MIC ≥16 mg/L, whereas none among the in vitro mutants. The RND efflux system AxyEF-OprN was overproduced (about 150-fold) in the in vitro mutant NCF-39-Bl6 versus its parental strain NCF-39 (ciprofloxacin MICs 64 and 1.5 mg/L, respectively). A substitution in AxyT (putative regulator of AxyEF-OprN) was detected in NCF-39-Bl6. Ciprofloxacin MIC in NCF-39-Bl6 dropped from 64 to 1.5 mg/L following gene inactivation of either axyT or axyF. Substitutions in AxyT associated with overexpression of AxyEF-OprN were also detected in seven clinical strains with ciprofloxacin MIC ≥16 mg/L. CONCLUSIONS: Target alteration is not the primary mechanism involved in fluoroquinolone resistance in Achromobacter. The role of AxyEF-OprN overproduction was demonstrated in one in vitro mutant.

Genomic islands related to Salmonella genomic island 1; integrative mobilisable elements in trmE mobilised in trans by A/C plasmids.

Salmonella genomic island 1 (SGI1), an integrative mobilisable element (IME), was first reported 20 years ago, in the multidrug resistant Salmonella Typhimurium DT104 clone. Since this first report, many variants and relatives have been found in Salmonella enterica and Proteus mirabilis. Thanks to whole genome sequencing, more and more complete sequences of SGI1-related elements (SGI1-REs) have been reported in these last few years among Gammaproteobacteria. Here, the genetic organisation and main features common to SGI1-REs are summarised to help to classify them. Their integrases belong to the tyrosine-recombinase family and target the 3'-end of the trmE gene. They share the same genetic organisation (integrase and excisionase genes, replicase module, SgaCD-like transcriptional activator genes, traN, traG, mpsB/mpsA genes) and they harbour AcaCD binding sites promoting their excision, replication and mobilisation in presence of A/C plasmid. SGI1-REs are mosaic structures suggesting that recombination events occurred between them. Most of them harbour a multiple antibiotic resistance (MAR) region and the plasticity of their MAR region show that SGI1-REs play a key role in antibiotic resistance and might help multiple antibiotic resistant bacteria to adapt to their environment. This might explain the emergence of clones with SGI1-REs.

SGI0, a relative of Salmonella genomic islands SGI1 and SGI2, lacking a class 1 integron, found in Proteus mirabilis.

Several groups of integrative mobilizable elements (IMEs) that harbour a class 1 integron carrying antibiotic resistance genes have been found at the 3'-end of the chromosomal trmE gene. Here, a new IME, designated SGI0, was found in trmE in the sequenced and assembled genome of a French clinical, multiply antibiotic resistant Proteus mirabilis strain, Pm1LENAR. SGI0 shares the same gene content as the backbones of SGI1 and SGI2 (overall 97.6% and 97.7% nucleotide identity, respectively) but it lacks a class 1 integron. However, SGI0 is a mosaic made up of segments with >98.5% identity to SGI1 and SGI2 interspersed with segments sharing 74-95% identity indicating that further diverged backbone types exist and that recombination between them is occurring. The structure of SGI1-V, here re-named SGI-V, which lacks two SGI1 (S023 and S024) backbone genes and includes a group of additional genes in the backbone, was re-examined. In regions shared with SGI1, the backbones shared 97.3% overall identity with the differences distributed in patches with various levels of identity. The class 1 integron is also in a slightly different position with the target site duplication AAATT instead of ACTTG for SGI1 and variants, indicating that it was acquired independently. The Pm1LENAR resistance genes are in the chromosome, in Tn7 and an ISEcp1-mobilised segment.

Carriage of a Single Strain of Nontoxigenic Corynebacterium diphtheriae bv. Belfanti (Corynebacterium belfantii) in Four Patients with Cystic Fibrosis.

Cystic fibrosis (CF) patients are commonly colonized by bacterial pathogens, which can induce persistent lung inflammation and may contribute to clinical deterioration. Colonization of CF patients and cross-transmission by Corynebacterium diphtheriae have not been reported so far. The aim of this article was to investigate the possibility of a cross-transmission of C. diphtheriae biovar Belfanti between four patients of a CF center. C. diphtheriae biovar Belfanti (now formally called C. belfantii) isolates were collected from four patients in a single CF care center over a period of 6 years and analyzed by microbiological methods and whole-genome sequencing. Epidemiological links among patients were investigated. Ten isolates were collected from 4 patients. Whole-genome sequencing of one isolate from each patient showed that a single strain was shared among them. In addition, one patient was found to have the same strain in two consecutive samplings performed 9 months apart. The strain was nontoxigenic and was susceptible to most antimicrobial agents. Ciprofloxacin resistance was observed in one patient. The idea of transmission of the strain among patients was supported by the occurrence of same-day visits to the CF center. This study demonstrated colonization of CF patients by C. diphtheriae biovar Belfanti (C. belfantii), and the data suggest persistence and transmission of a unique strain during at least 6 years in a single CF patient care center.

Identification of AGI1-A, a variant of Acinetobacter genomic island 1 (AGI1), in a French clinical isolate belonging to the Enterobacter cloacae complex.

Objectives: To characterize the structure of a variant of Acinetobacter genomic island 1 (AGI1) in the Enterobacter cloacae clinical isolate EclC2185 responsible for an 8 year outbreak in Dijon University Hospital. Methods: The genome was sequenced (Miseq) and de novo assembled (Velvet). PCR and Sanger sequencing were performed to determine the sequence of the genomic island. Results: The new variant of AGI1 named AGI1-A (41.7 kb), located at the 3' end of the chromosomal trmE, was detected in an E. cloacae complex isolate identified as Enterobacter hormaechei subsp. oharae. The backbone of AGI1-A lacked A008, part of A025, A026 and the resolvase gene. Its MDR region (19.7 kb) contained two integrons followed by a hybrid transposon Tn502/Tn5053. The former integron was a typical In4-type class 1 integron carrying aadA1 and the latter integron carrying dfrA1 did not belong to a class described to date. The nucleotide sequence intI-dfrA1 was surrounded by a 78 bp imperfect repeat sequence in inverse orientation. An external circular form of AGI1-A was detected, suggesting potential mobility. AGI1-A was also detected in 15 isolates from the outbreak selected at random. They belonged to the ST114 high-risk clone. Conclusions: AGI1-A, a variant of AGI1 described in Acinetobacter baumannii, is the first genomic resistance island belonging to the Salmonella genomic island/Proteus genomic island/Acinetobacter genomic island family detected in E. cloacae. One might, therefore, fear for interspecies dissemination of genomic islands from this family.

Genomic context of resistance genes within a French clinical MDR Proteus mirabilis: identification of the novel genomic resistance island GIPmi1.

Objectives: To determine the location of the antibiotic resistance genes in the MDR Proteus mirabilis PmPHI clinical isolate. Methods: WGS and de novo assembly were performed. BLAST searches were used to identify relevant contigs. PCR and Sanger sequencing were used to link the fragments of interest and fill the gaps. Results: P. mirabilis PmPHI was resistant to six classes of antibiotics: penicillins, aminoglycosides, phenicols, tetracyclines, folate inhibitors and fluoroquinolones. A novel genomic resistance island (GIPmi1) of 55.8 kb was located at the 3' end of trmE. The backbone shared 93% identity with a genomic sequence of Enterobacter cloacae DSM 16690. The MDR region was composed of two class 1 integrons [one Tn402-type (estX-qacE) and one In5-type (aadB-aadA2)], separated by a region containing many parts of transposons. An external circular form of GIPmi1 was detected; however, mobilization by an A/C plasmid failed. In addition, an SXT/R391 integrative and conjugative element (ICEPmiFra1) was inserted into prfC. It carried floR, the sul2-strA-strB cluster and a composite transposon flanked by two copies of a tISPpu12 element that contains a class 1 integron (dfrA32-ereA1-aadA2), Tn4352 (aphA1a) and tetA(C). A class 2 integron (dfrA1-sat2-aadA1) was also identified on Tn7 as well as point mutations in gyrA and parC accounting for quinolone resistance. Conclusions: The finding of the new genomic island GIPmi1 belonging to the same superfamily of genomic islands as SGI1/SGI2/PGI1/AGI1 and of the integrative conjugative element ICEPmiFra1 (SXT/R391 family) suggested that these genetic elements might be key mediators of resistance gene acquisition in P. mirabilis.

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 integrons framed a complex region (harbouring among others blaCARB-4) resulting from transposon insertions mediated by IS26 and successive transposition events of ISs (ISAba14 isoform and the new ISPmi2). The second variant (SGI1-K7) had the same backbone as SGI1-K. Its MDR region (29.7 kb) was derived from that of SGI1-K and was generated by three events. The two main events were mediated by IS26: inversion of a large portion of the MDR region of SGI1-K and insertion of a structure previously reported on plasmids carried by prevalent and successful MDR clones of Enterobacteriaceae. This last event led to the insertion of the blaCTX-M-15 gene into SGI1-K7. Conclusions: This study confirmed the great plasticity of the MDR region of SGI1 and its potential key role for the dissemination of clinically significant antibiotic resistance among Enterobacteriaceae.

Nosocomial Infections with IMP-19-Producing Pseudomonas aeruginosa Linked to Contaminated Sinks, France.

We isolated IMP-19-producing Pseudomonas aeruginosa from 7 patients with nosocomial infections linked to contaminated sinks in France. We showed that blaIMP-19 was located on various class 1 integrons among 8 species of gram-negative bacilli detected in sinks: P. aeruginosa, Achromobacter xylosoxidans, A. aegrifaciens, P. putida, Stenotrophomonas maltophilia, P. mendocina, Comamonas testosteroni, and Sphingomonas sp.

Role of AxyZ Transcriptional Regulator in Overproduction of AxyXY-OprZ Multidrug Efflux System in Achromobacter Species Mutants Selected by Tobramycin.

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 colonization in a cystic fibrosis (CF) patient. This substitution, also detected in three other strains exposed in vitro to tobramycin, led to an increase in the axyY transcription level (5- to 17-fold) together with an increase in antibiotic resistance level. This overproduction of AxyXY-OprZ is the first description of antibiotic resistance acquisition due to modification of a chromosomally encoded mechanism in Achromobacter and might have an impact on the management of infected CF patients. Indeed, tobramycin is widely used for aerosol therapy within this population, and we have demonstrated that it easily selects mutants with increased MICs of not only aminoglycosides but also fluoroquinolones, cefepime, and tetracyclines.

Streptococcus pyogenes: an unusual cause of salpingitis. Case report and review of the literature.

BACKGROUND: Streptococcus pyogenes can colonize genitourinary tract, but it is a rare cause of salpingitis. CASE REPORT: We report a case of bilateral salpingitis due to Streptococcus pyogenes in a 34-year-old woman using an intra-uterine device and which occurred following a family history of recurrent S. pyogenes infections. We review 12 other cases reported in the literature, and discuss the pathophysiological mechanisms of this potentially life-threatening disease. CONCLUSION: It is important to take into account consider Streptococcus pyogenes as a cause of acute salpingitis in the context of recent intra-familial Streptococcus pyogenes infections.

"Does the Salmonella Genomic Island 1 (SGI1) confer invasiveness properties to human isolates?"

BACKGROUND: In the eighties, a multidrug resistant clone of Salmonella Typhimurium DT104 emerged in UK and disseminated worldwide. This clone harbored a Salmonella genomic island 1 (SGI1) that consists of a backbone and a multidrug resistant region encoding for penta-resistance (ampicillin, chloramphenicol/florfenicol, streptomycin/spectinomycin, sulphonamides and tetracycline (ACSSuT)). Several authors suggested that SGI1 might have a potential role in enhancement of virulence properties of Salmonella enterica. The aim of this study was to investigate whether nontyphoidal S. enterica isolates carrying SGI1 cause more severe illness than SGI1 free ones in humans. METHODS: From 2011 to 2016, all patients infected with nontyphoidal S. enterica in our hospital were retrospectively included. All nontyphoidal S. enterica isolates preserved in our University Hospital (Dijon, France) were screened for the presence of SGI1. Clinical and biological data of patients were retrospectively collected to evaluate illness severity. Statistical analysis of data was performed by Kruskal-Wallis test or Fisher's exact test for univariate analysis, and by logistic regression for multivariate analysis. RESULTS: A total of 100 isolates of S. enterica (22 serovars) were collected. Twelve isolates (12%) belonging to 4 serovars harbored SGI1: S. Typhimurium, S. Infantis, S. Kentucky, S. St Paul. The severity of the disease was age-related (for invasive infection, sepsis and inflammatory response) and was associated with immunosuppression (for invasive infection, sepsis and bacteremia) but not with the presence of SGI1 or with antimicrobial resistance. CONCLUSION: A rather high proportion (12%) of human clinical isolates belonging to various serovars (for the first time serovar St Paul) and harboring various antimicrobial resistance profile carried SGI1. Diseases due to SGI1-positive S. enterica or to antimicrobial resistant isolates were not more severe than the others. This first clinical observation should be confirmed by a multicenter and prospective study.

Mobilization of the Salmonella genomic island SGI1 and the Proteus genomic island PGI1 by the A/C2 plasmid carrying blaTEM-24 harboured by various clinical species of Enterobacteriaceae.

OBJECTIVES: The objective of this study was to transfer the Salmonella genomic islands (GIs) SGI1 and SGI1-V and the Proteus GI PGI1-PmESC to clinical isolates of Enterobacteriaceae harbouring an A/C2 plasmid. METHODS: The entire genetic structures of SGI1 and PGI1-PmESC from Salmonella Typhimurium and Proteus mirabilis, respectively, were characterized by PCR and DNA sequencing. Ten enterobacterial isolates from different species carrying blaTEM-24 on an A/C2 plasmid were used for the mobilization of SGI1: Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter aerogenes, Citrobacter freundii, Klebsiella oxytoca, Proteus vulgaris, Providencia stuartii and Serratia marcescens. SGI1-V and PGI1-PmESC were transferred to E. aerogenes. Conjugation attempts were also performed using the wild strain E. aerogenes BOL and E. coli K-12 with or without pA/C2. Detection and location of the GI in the transconjugants were assessed by PCR targeting their junctions. RESULTS: The multidrug resistance region of PGI1-PmESC contained a class 1 integron (aadB and aadA2) and regions deriving from transposon Tn501 and a hybrid Tn502/Tn5053 transposon, whereas SGI1 harboured the known determinants responsible for the pentaresistance. The transfer of SGI1 occurred from Salmonella Typhimurium to the 10 enterobacterial isolates, and transfer of SGI1-V and PGI1-PmESC occurred from P. mirabilis to E. aerogenes. In all transconjugants the GI was located at the 3'-end of trmE. SGI1 was also transferred to E. aerogenes BOL (pA/C2) and E. coli K-12 (pA/C2), but not to E. aerogenes BOL and E. coli K-12. CONCLUSIONS: This is the first known description of SGI1 mobilization into a broad range of enterobacterial species harbouring an A/C2 plasmid and the first demonstration of PGI1 movement. The A/C2 plasmid is responsible for the GI mobilization.

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.

Amperometric detection of extended-spectrum ß-lactamase activity: application to the characterization of resistant E. coli strains.

The amperometric detection of extended-spectrum ß-lactamase (ESBL) with carbon screen-printed sensors was investigated in the presence of the Nitrocefin, a commercially-available ß-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 = ∼+0.3 V vs. Ag/AgCl) resulting from the catalytic hydrolysis of the ß-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 scheme relied on (i) the culture of the sample in a medium containing the cefotaxime supplemented or not with the clavulanic acid inhibitor to allow the specific determination of ESBL producers (ii) followed by the incubation of the bacteria with the Nitrocefin and (iii) the measurement of the enzyme product by cyclic voltammetry. The amperometric assay was further applied to the characterization of E. coli strains and to the quantification of the ESBL producers. A detection limit of 5 × 10(4) cfu mL(-1) ESBL-producing E. coli was achieved after a 10 min incubation time. In contrast to the approved routine assays, the electrochemical approach, which did not require isolated colonies to be performed, provided quantified results regarding ESBL activity within a few hours. Finally, owing to its cost-effectiveness, portability and simplicity, this test holds great promise for clinical and environmental applications.