Molecularly imprinted polymers for per- and polyfluoroalkyl substances enrichment and detection.

Per- and polyfluoroalkyl substances (PFAS) are highly toxic pollutants of significant concern as they are being detected in water, air, fish and soil. They are extremely persistent and accumulate in plant and animal tissues. Traditional methods of detection and removal of these substances use specialised instrumentation and require a trained technical resource for operation. Molecularly imprinted polymers (MIPs), polymeric materials with predetermined selectivity for a target molecule, have recently begun to be exploited in technologies for the selective removal and monitoring of PFAS in environmental waters. This review offers a comprehensive overview of recent developments in MIPs, both as adsorbents for PFAS removal and sensors that selectively detect PFAS at environmentally-relevant concentrations. PFAS-MIP adsorbents are classified according to their method of preparation (e.g., bulk or precipitation polymerization, surface imprinting), while PFAS-MIP sensing materials are described and discussed according to the transduction methods used (e.g., electrochemical, optical). This review aims to comprehensively discuss the PFAS-MIP research field. The efficacy and challenges facing the different applications of these materials in environmental water applications are discussed, as well as a perspective on challenges for this field that need to be overcome before exploitation of the technology can be fully realised.

Modified 3D-printed device for mercury determination in waters.

3D printing technology is increasingly used in flow analysis, to develop low cost and tailor-made devices. The possibility of grafting specific molecules onto 3D printed parts offers new perspectives for the development of flow systems. In this study, a MPFS system including a dicarboxylate 1,5-diphenyl-3-thiocarbazone grafted 3D-printed device has been developed for mercury determination. For this purpose, the surface of 3D-printed cuboids was first modified with amine functional groups and then grafted with dicarboxylate 1,5-diphenyl-3-thiocarbazone. This new grafted device resulted in selective mercury preconcentration with extraction and elution yields higher than 90% even at high sampling flow rates. The detection can then be carried out in two ways: a direct detection of mercury extracted onto 3D-printed grafted cuboids by atomic absorption spectrophotometry after amalgam on gold or a detection of mercury in solution after elution with l-cysteine by spectrophotometry or cold vapour atomic absorption spectrometry.

Specialization of small non-conjugative plasmids in Escherichia coli according to their family types.

We undertook a comprehensive comparative analysis of a collection of 30 small (<25 kb) non-conjugative Escherichia coli plasmids previously classified by the gene sharing approach into 10 families, as well as plasmids found in the National Center for Biotechnology Information (NCBI) nucleotide database sharing similar genomic sequences. In total, 302 mobilizable (belonging to 2 MOBrep and 5 MOBRNA families) and 106 non-transferable/relaxase-negative (belonging to three ReLRNA families) plasmids were explored. The most striking feature was the specialization of the plasmid family types that was not related to their transmission mode and replication system. We observed a range of host strain specificity, from narrow E. coli host specificity to broad host range specificity, including a wide spectrum of Enterobacteriaceae. We found a wide variety of toxin/antitoxin systems and colicin operons in the plasmids, whose numbers and types varied according to the plasmid family type. The plasmids carried genes conferring resistance spanning almost all of the antibiotic classes, from those to which resistance developed early, such as sulphonamides, to those for which resistance has only developed recently, such as colistin. However, the prevalence of the resistance genes varied greatly according to the family type, ranging from 0 to 100 %. The evolutionary history of the plasmids based on the family type core genes showed variability within family nucleotide divergences in the range of E. coli chromosomal housekeeping genes, indicating long-term co-evolution between plasmids and host strains. In rare cases, a low evolutionary divergence suggested the massive spread of an epidemic plasmid. Overall, the importance of these small non-conjugative plasmids in bacterial adaptation varied greatly according to the type of family they belonged to, with each plasmid family having specific hosts and genetic traits.

Identifying the Stoichiometry of Metal/Ligand Complex by Coupling Spectroscopy and Modelling: a Comprehensive Study on Two Fluorescent Molecules Specific to Lead.

Two new chemosensors for lead (II) were synthesized based on 5-((anthracen-9-ylmethylene) amino)quinolin-10-ol (ANQ). ANQ was modified in the para position of the imine group via a methoxy link either with methylmethacrylate (ANQ-MMA) or styrene (ANQ-ST). Complexation of those molecules with Pb2+ was studied at room temperature using UV-Visible absorption and fluorescence spectroscopies. Thanks to the UV-visible absorption spectroscopy, it appeared that ANQ-MMA formed 1:1 and 1:2 complexes with lead (II) and ANQ-ST only 1:1 complex. For both molecules, the fluorescence excitation-emission matrices (EEM) signal intensity increased from 0 to 100 µmol.L-1 of lead (II) followed by a saturation for higher concentrations. The decomposition of the obtained EEMs gave a set of empiric fluorescent components that have been directly linked to the distribution of lead complexes obtained with the UV-visible absorption spectroscopy study. This correlation allowed to evidence metal/ligand complex stoichiometry and emerge as a new method to identify empiric components. Moreover, the two ligands showed a promising selectivity for Pb2+, turning them interesting probes for this hazardous metal.

Advantage of the F2:A1:B- IncF Pandemic Plasmid over IncC Plasmids in In Vitro Acquisition and Evolution of blaCTX-M Gene-Bearing Plasmids in Escherichia coli.

Despite a fitness cost imposed on bacterial hosts, large conjugative plasmids play a key role in the diffusion of resistance determinants, such as CTX-M extended-spectrum ß-lactamases. Among the large conjugative plasmids, IncF plasmids are the most predominant group, and an F2:A1:B- IncF-type plasmid encoding a CTX-M-15 variant was recently described as being strongly associated with the emerging worldwide Escherichia coli sequence type 131 (ST131)-O25b:H4 H30Rx/C2 sublineage. In this context, we investigated the fitness cost of narrow-range F-type plasmids, including the F2:A1:B- IncF-type CTX-M-15 plasmid, and of broad-range C-type plasmids in the K-12-like J53-2 E. coli strain. Although all plasmids imposed a significant fitness cost to the bacterial host immediately after conjugation, we show, using an experimental-evolution approach, that a negative impact on the fitness of the host strain was maintained throughout 1,120 generations with the IncC-IncR plasmid, regardless of the presence or absence of cefotaxime, in contrast to the F2:A1:B- IncF plasmid, whose cost was alleviated. Many chromosomal and plasmid rearrangements were detected after conjugation in transconjugants carrying the IncC plasmids but not in transconjugants carrying the F2:A1:B- IncF plasmid, except for insertion sequence (IS) mobilization from the fliM gene leading to the restoration of motility of the recipient strains. Only a few mutations occurred on the chromosome of each transconjugant throughout the experimental-evolution assay. Our findings indicate that the F2:A1:B- IncF CTX-M-15 plasmid is well adapted to the E. coli strain studied, contrary to the IncC-IncR CTX-M-15 plasmid, and that such plasmid-host adaptation could participate in the evolutionary success of the CTX-M-15-producing pandemic E. coli ST131-O25b:H4 lineage.

The Arginine Deiminase Operon Is Responsible for a Fitness Trade-Off in Extended-Spectrum-ß-Lactamase-Producing Strains of Escherichia coli.

We previously identified an operon involved in an arginine deiminase (ADI) pathway (arc operon) on a CTX-M-producing plasmid from an O102-ST405 strain of Escherichia coli As the ADI pathway was shown to be involved in the virulence of various Gram-positive bacteria, we tested whether the ADI pathway could be involved in the epidemiological success of extended-spectrum-ß-lactamase (ESBL)-producing E. coli strains. We studied two collections of human E. coli isolated in France (n = 493) and England (n = 1,509) and show that the prevalence of the arc operon (i) is higher in ESBL-producing strains (12.1%) than in nonproducers (2.5%), (ii) is higher in CTX-M-producing strains (16%) than in other ESBL producers (3.5%), and (iii) increased over time in ESBL-producing strains from 0% before 2000 to 43.3% in 2011 to 2012. The arc operon, found in strains from various phylogenetic backgrounds, is carried by IncF plasmids (85%) or chromosomes (15%) in regions framed by numerous insertion sequences, indicating multiple arrivals. Competition experiments showed that the arc operon enhances fitness of the strain in vitro in lysogeny broth with arginine. In vivo competition experiments showed that the arc operon is advantageous for the strain in a mouse model of urinary tract infection (UTI), whereas it is a burden in a mouse model of intestinal colonization. In summary, we have identified a trait linked to CTX-M-producing strains that is responsible for a trade-off between two main E. coli lifestyles, UTI and gut commensalism. This trait alone cannot explain the wide spread of ESBLs in E. coli but merits epidemiological surveillance.

Risk Factors for Infant Colonization by Hypervirulent CC17 Group B Streptococcus: Toward the Understanding of Late-onset Disease.

BACKGROUND: In infants, the mode of acquisition of CC17 group B Streptococcus (GBS), the hypervirulent clone responsible for late-onset disease (LOD), remains elusive. METHODS: In a prospective multicenter study in France, we evaluated GBS colonization in mother-baby pairs with 2 months of follow-up between 2012 and 2015. Criteria included positivity for GBS colonization at antenatal screening or at delivery. Maternal vaginal samples and infant oral cavity and stool samples were analyzed at delivery, 21 ± 7 days (D21), and 60 ± 7 days (D60) post-delivery. RESULTS: A total of 890 mother-baby pairs were analyzed. GBS colonized 7%, 21%, and 23% of the infants at birth, D21, and D60, respectively, of which 10%, 11%, and 13% were identified as CC17 GBS. Concordance between maternal and infant GBS type was 96%. At D21, the main risk factors for infant colonization by GBS were simultaneous maternal colonization of the vagina (odds ratio [OR], 4.50; 95% confidence interval [CI], 1.69-15.61) and breast milk (OR, 7.93; 95% CI, 3.81-17.14). Importantly, 38% (95% CI, 23%-56%) of infants colonized by CC17 GBS appeared colonized for the first time at D60 vs 18% (95% CI, 14%-24%; P < .049) of infants colonized by non-CC17 GBS. Multivariate analysis showed a higher risk for de novo infant colonization by CC17 at D60 than by other GBS (OR, 2.45; 95% CI, 1.02-5.88). CONCLUSIONS: The high incidence of CC17 GBS in LOD is likely due to an enhanced post-delivery mother-to-infant transmission.

Oropharyngeal Bacterial Colonization after Chlorhexidine Mouthwash in Mechanically Ventilated Critically Ill Patients.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Oropharyngeal care with chlorhexidine to prevent ventilator-associated pneumonia is currently questioned, and exhaustive microbiologic data assessing its efficacy are lacking. The authors therefore aimed to study the effect of chlorhexidine mouthwash on oropharyngeal bacterial growth, to determine chlorhexidine susceptibility of these bacteria, and to measure chlorhexidine salivary concentration after an oropharyngeal care. METHODS: This observational, prospective, single-center study enrolled 30 critically ill patients under mechanical ventilation for over 48 h. Oropharyngeal contamination was assessed by swabbing the gingivobuccal sulcus immediately before applying 0.12% chlorhexidine with soaked swabs, and subsequently at 15, 60, 120, 240, and 360 min after. Bacterial growth and identification were performed, and chlorhexidine minimal inhibitory concentration of recovered pathogens was determined. Saliva was collected in 10 patients, at every timepoint, with an additional timepoint after 30 min, to measure chlorhexidine concentration. RESULTS: Two hundred fifty bacterial samples were analyzed and identified 48 pathogens including Streptococci (27.1%) and Enterobacteriaceae (20.8%). Oropharyngeal contamination before chlorhexidine mouthwash ranged from 10 to 10 colony-forming units (CFU)/ml in the 30 patients (median contamination level: 2.5·10 CFU/ml), and remained between 8·10 (lowest) and 3·10 CFU/ml (highest count) after chlorhexidine exposure. These bacterial counts did not decrease overtime after chlorhexidine mouthwash (each minute increase in time resulted in a multiplication of bacterial count by a coefficient of 1.001, P = 0.83). Viridans group streptococci isolates had the lowest chlorhexidine minimal inhibitory concentration (4 [4 to 8] mg/l); Enterobacteriaceae isolates had the highest ones (32 [16 to 32] mg/l). Chlorhexidine salivary concentration rapidly decreased, reaching 7.6 [1.8 to 31] mg/l as early as 60 min after mouthwash. CONCLUSIONS: Chlorhexidine oropharyngeal care does not seem to reduce bacterial oropharyngeal colonization in critically ill ventilated patients. Variable chlorhexidine minimal inhibitory concentrations along with low chlorhexidine salivary concentrations after mouthwash could explain this ineffectiveness, and thus question the use of chlorhexidine for ventilator-associated pneumonia prevention.

Extended-spectrum ß-lactamase-encoding genes are spreading on a wide range of Escherichia coli plasmids existing prior to the use of third-generation cephalosporins.

To understand the evolutionary dynamics of extended-spectrum ß-lactamase (ESBL)-encoding genes in Escherichia coli, we undertook a comparative genomic analysis of 116 whole plasmid sequences of human or animal origin isolated over a period spanning before and after the use of third-generation cephalosporins (3GCs) using a gene-sharing network approach. The plasmids included 82 conjugative, 22 mobilizable and 9 non-transferable plasmids and 3 P-like bacteriophages. ESBL-encoding genes were found on 64 conjugative, 6 mobilizable, 2 non-transferable plasmids and 2 P1-like bacteriophages, indicating that these last three types of mobile elements also play a role, albeit modest, in the diffusion of the ESBLs. The network analysis showed that the plasmids clustered according to their genome backbone type, but not by origin or period of isolation or by antibiotic-resistance type, including type of ESBL-encoding gene. There was no association between the type of plasmid and the phylogenetic history of the parental strains. Finer scale analysis of the more abundant clusters IncF and IncI1 showed that ESBL-encoding plasmids and plasmids isolated before the use of 3GCs had the same diversity and phylogenetic history, and that acquisition of ESBL-encoding genes had occurred during multiple independent events. Moreover, the blaCTX-M-15 gene, unlike other CTX-M genes, was inserted at a hot spot in a blaTEM-1-Tn2 transposon. These findings showed that ESBL-encoding genes have arrived on wide range of pre-existing plasmids and that the successful spread of blaCTX-M-15 seems to be favoured by the presence of well-adapted IncF plasmids that carry a Tn2-blaTEM-1 transposon.

Hypervirulent Klebsiella pneumoniae, a 5-year study in a French ICU.

PURPOSE: Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a leading cause of severe community-acquired pneumonia, liver abscess and disseminated infection in the Far East. Data regarding the incidence, clinical features and microbiological characteristics related to hvKp infections in the Western world are scarce. METHODOLOGY: The incidence, clinical features and microbiological characteristics of hvKp infections were investigated through a 5-year survey conducted in a single French intensive care unit. K. pneumoniae strains were screened for hypermucoviscosity based on a string test. Multilocus sequence typing and multiplex PCR analysis targeting virulence genes were performed on string test-positive strains. RESULTS: Over a 53-month period, a total of 59 infections due to K. pneumoniae were identified including 26 community-onset infections. Twelve hvKp infections were documented, accounting for 46.1 % of community-acquired K. pneumoniae. Community-acquired pneumonia (n=6), aspiration pneumonia (n=4) and liver abscess (n=2) represented initial sites and mode of infection. Compared to non-hvKp infections, patients with hvKp infections displayed higher rates of multi-organ failure (83.3 % vs 35.7 %; P=0.04), but mortality rates were not different (50 % vs 35 %; P=0.71). Strains K1/ST23 (n=5) and K2/ST86 (n=5) predominated. All hvKp strains displayed wild-type susceptibility. CONCLUSION: hvKp represent a potentially underestimated cause of fatal infections in the Western world.

Detection of Bisphenol A in aqueous medium by screen printed carbon electrodes incorporating electrochemical molecularly imprinted polymers.

Electrochemical molecularly imprinted polymers (e-MIPs) were for the first time introduced in screen-printed carbon electrodes (SPCE) as the sensing element for the detection of an organic pollutant. To play this sensing role, a redox tracer was incorporated inside the binding cavities of a cross-linked MIP, as a functional monomer during the synthesis step. Ferrocenylmethyl methacrylate was used for this purpose. It was associated with 4-vinylpyridine as a co-functional monomer and ethylene glycol dimethacrylate as cross-linker for the recognition of the endocrine disruptor, Bisphenol A (BPA), as a target. Microbeads of e-MIP and e-NIP (corresponding non-imprinted polymer) were obtained via precipitation polymerization in acetonitrile. The presence of ferrocene inside the polymers was assessed via FTIR and elemental analysis and the polymers microstructure was characterized by SEM and nitrogen adsorption/desorption experiments. Binding isotherms and batch selectivity experiments evidenced the presence of binding cavities inside the e-MIP and its high affinity for BPA compared to carbamazepine and ketoprofen. e-MIP (and e-NIP) microbeads were then incorporated in a graphite-hydroxyethylcellulose composite paste to prepare SPCE. Electrochemical properties of e-MIP-SPCE revealed a high sensitivity in the presence of BPA in aqueous medium compared to e-NIP-SPCE with a limit of detection (LOD) of 0.06 nM. Selectivity towards carbamazepine and ketoprofen was also observed with the e-MIP-SPCE.

3D-printed lab-on-valve for fluorescent determination of cadmium and lead in water.

In recent years, the development of 3D printing in flow analysis has allowed the creation of new systems with various applications. Up to now, 3D printing was mainly used for the manufacture of small units such as flow detection cells, preconcentration units or mixing systems. In the present study, a new 3D printed lab-on-valve system was developed to selectively quantify lead and cadmium in water. Different technologies were compared for lab-on-valve 3D printing. Printed test units have shown that stereolithography or digital light processing are satisfactory techniques for creating complex lab-on-valve units. The lab-on-valve system was composed of two columns, eight peripheral ports and a central port, and a coil integrating baffles to increase mixing possibilities. A selective extraction of lead was first carried out by TrisKem Pb™ Resin column. Then, cadmium not retained on the first column was extracted on a second column of Amberlite® IR 120 resin. In a following step, lead and cadmium were eluted with ammonium oxalate and potassium iodide, respectively. Finally, the two metals were sequentially detected by the same Rhod-5N™ fluorescent reagent. This 3D printed lab-on-valve flow system allowed us to quantify lead and cadmium with a linear response from 0.2 to 15 µg L-1 and detection limits of 0.17 and 0.20 µg L-1 for lead and cadmium, respectively, which seems adapted for natural water analysis.

3D-printed flow system for determination of lead in natural waters.

The development of 3D printing in recent years opens up a vast array of possibilities in the field of flow analysis. In the present study, a new 3D-printed flow system has been developed for the selective spectrophotometric determination of lead in natural waters. This system was composed of three 3D-printed units (sample treatment, mixing coil and detection) that might have been assembled without any tubing to form a complete flow system. Lead was determined in a two-step procedure. A preconcentration of lead was first carried out on TrisKem Pb Resin located in a 3D-printed column reservoir closed by a tapped screw. This resin showed a high extraction selectivity for lead over many tested potential interfering metals. In a second step, lead was eluted by ammonium oxalate in presence of 4-(2-pyridylazo)-resorcinol (PAR), and spectrophotometrically detected at 520nm. The optimized flow system has exhibited a linear response from 3 to 120µgL-1. Detection limit, coefficient of variation and sampling rate were evaluated at 2.7µgL-1, 5.4% (n=6) and 4 sampleh-1, respectively. This flow system stands out by its fully 3D design, portability and simplicity for low cost analysis of lead in natural waters.

Structural Alteration of OmpR as a Source of Ertapenem Resistance in a CTX-M-15-Producing Escherichia coli O25b:H4 Sequence Type 131 Clinical Isolate.

In this study, an ertapenem-nonsusceptible Escherichia coli isolate was investigated to determine the genetic basis for its carbapenem resistance phenotype. This clinical strain was recovered from a patient that received, 1 year previously, ertapenem to treat a cholangitis due to a carbapenem-susceptible extended-spectrum-ß-lactamase (ESBL)-producing E. coli isolate. Whole-genome sequencing of these strains was performed using Illumina and single-molecule real-time sequencing technologies. It revealed that they belonged to the ST131 clonal group, had the predicted O25b:H4 serotype, and produced the CTX-M-15 and TEM-1 ß-lactamases. One nucleotide substitution was identified between these strains. It affected the ompR gene, which codes for a regulatory protein involved in the control of OmpC/OmpF porin expression, creating a Gly-63-Val substitution. The role of OmpR alteration was confirmed by a complementation experiment that fully restored the susceptibility to ertapenem of the clinical isolate. A modeling study showed that the Gly-63-Val change displaced the histidine-kinase phosphorylation site. SDS-PAGE analysis revealed that the ertapenem-nonsusceptible E. coli strain had a decreased expression of OmpC/OmpF porins. No significant defect in the growth rate or in the resistance to Dictyostelium discoideum amoeba phagocytosis was found in the ertapenem-nonsusceptible E. coli isolate compared to its susceptible parental strain. Our report demonstrates for the first time that ertapenem resistance may emerge clinically from ESBL-producing E. coli due to mutations that modulate the OmpR activity.

Phylogenetic, virulence and antibiotic resistance characteristics of commensal strain populations of Escherichia coli from community subjects in the Paris area in 2010 and evolution over 30 years.

It is important to study commensal populations of Escherichia coli because they appear to be the reservoir of both extra-intestinal pathogenic E. coli and antibiotic resistant strains of E. coli. We studied 279 dominant faecal strains of E. coli from 243 adults living in the community in the Paris area in 2010. The phylogenetic group and subgroup [sequence type complex (STc)] of the isolates and the presence of 20 virulence genes were determined by PCR assays. The O-types and resistance to 18 antibiotics were assessed phenotypically. The B2 group was the most frequently recovered (34.0 %), followed by the A group (28.7 %), and other groups were more rare. The most prevalent B2 subgroups were II (STc73), IV (STc141), IX (STc95) and I (STc131), with 22.1, 21.1, 16.8 and 13.7 %, respectively, of the B2 group strains. Virulence factors (VFs) were more common in B2 group than other strains. One or more resistances were found in 125 strains (44.8 % of the collection) but only six (2.2 % of the collection) were multiresistant; no extended-spectrum beta-lactamase-producing strain was isolated. The C phylogroup and clonal group A strains were the most resistant. No trade-off between virulence and resistance was evidenced. We compared these strains with collections of strains gathered under the same conditions 30 and 10 years ago. There has been a parallel and linked increase in the frequency of B2 group strains (from 9.4 % in 1980, to 22.7 % in 2000 and 34.0 % in 2010) and of VFs. Antibiotic resistance also increased, from 22.6 % of strains resistant to at least one antibiotic in 1980, to 31.8 % in 2000 and 44.8 % in 2010; resistance to streptomycin, however, remained stable. Commensal human E. coli populations have clearly evolved substantially over time, presumably reflecting changes in human practices, and particularly increasing antibiotic use.

An innovative approach to prepare hypericin molecularly imprinted pearls using a "phyto-template".

In this paper, an innovative method that uses hypericin "phyto-template" molecules is being applied herein for the first time to produce molecularly imprinted polymer (MIP) pearls able to selectively retain hypericin from Hypericum Perforatum L primary extracts. For this purpose, the wet phase inversion method was preferred for preparing the hypericin-MIP pearls for several reasons referring to economical benefits but also due to the fact that hypericin "phyto-template" molecules can be generated along with the phase inversion of the copolymer. Practically, the precursor poly(acrylonitrile-co-methacrylic acid) solution was mixed with a purified and concentrated naphtodianthrone phyto-extract (consisting only of hypericin and pseudo-hypericin). In the subsequent phase inversion step hypericin was trapped in the copolymer droplets, as a result to its poor solubility in the inversion water bath, and further served as "phyto-template" in the imprinting step. This in situ repartition of hypericin and pseudo-hypericin was sustained by HPLC-DAD chromatograms which recorded only the presence of hypericin during the extraction stage of imprinted pearls. Batch rebinding measurements, all together, validated the efficiency of this innovative imprinting procedure. The hypericin rebinding of imprinted pearls was quantitative (up to 318 µg/L) and approximately 5 times more specific relative to the blank pearls. Competitive re-binding revealed a more selective behaviour of imprinted pearls for hypericin when the up-take was measured against pseudohypericin (selectivity coefficient above 4.50).

Five-year trends for ventilator-associated pneumonia: Correlation between microbiological findings and antimicrobial drug consumption.

The epidemiology of multidrug-resistant bacteria (MDRB) has changed significantly in European healthcare settings, with a decrease in frequency of meticillin-resistant Staphylococcus aureus and an increase in extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae. Little is known about the effects of these changes on ventilator-associated pneumonia (VAP). A retrospective 5-year trend analysis of ICU antibiotic consumption and resistance in bacteria causing VAP was undertaken. Poisson regression analysis between complete microbiological data and antibiotic consumption was performed. In total, 252 episodes of VAP in 184 patients were identified between 2007 and 2011, from which 364 causal bacteria were isolated. Enterobacteriaceae isolation rates increased significantly over this period [from 6.64 to 10.52 isolates/1000 patient-days; P=0.006], mostly due to an increase in AmpC-producing Enterobacteriaceae (APE) (2.85-4.51 isolates/1000 patient-days; P=0.013), whereas the number of episodes due to S. aureus and Pseudomonas aeruginosa remained stable. A positive association was found between the increase in APE infections and an increase in past-year antibiotic consumption: amoxicillin/clavulanic acid (P=0.003), ceftazidime and cefepime (P=0.007), carbapenems (P=0.002), fluoroquinolones (P=0.012), macrolides (P=0.002) and imidazoles (P=0.004). No such association was found for the emergence of resistance in P. aeruginosa. These results indicate a change in the epidemiology of VAP, with Enterobacteriaceae exceeding P. aeruginosa and S. aureus. Moreover, a positive correlation was observed between antibiotic consumption and the incidence of potentially MDRB such as APE. No such correlation was found for ESBL-producing Escherichia coli and antibiotic-resistant P. aeruginosa.

Assessment and modelling of Ni(II) retention by an ion-imprinted polymer: application in natural samples.

Three novel Ni(II)-Ion-Imprinted Polymer (IIP) were synthesized by precipitation polymerization of ethylene glycol dimethacrylate (crosslinker) with a complex of nickel(II) and vinylbenzyl iminodiacetic acid (VbIDA). The three IIPs were prepared with various mixtures of porogen solvents: methanol, methanol/2-methoxyethanol and methanol/acetonitrile (IIP1, IIP2 and IIP3, respectively). Non-Imprinted Polymers (NIP1, NIP2 and NIP3) were prepared as control polymers in similar conditions but with pure VbIDA instead of VbIDA-Ni. These polymers were characterized by FTIR, BET, SEM and tested for their efficiency and selectivity in Ni(II) retention. The most efficient (IIP1, around 12 mg g(-1) of nickel) was then positively checked for Ni(II) retention in presence of some competing species over a wide range of concentration. Finally Ni(II) retention by IIP1 was successfully demonstrated in natural samples. The modelling of the different experiments (Langmuir, Freundlich but also PROSECE and WHAM VII, frequently used in environmental studies) allowed demonstrating the presence of completely different binding sites when considering the ion-imprinted polymer and the non-imprinted one, and therefore led to a better understanding of what the imprinting effect is.

Effects of Proanthocyanidins on Adhesion, Growth, and Virulence of Highly Virulent Extraintestinal Pathogenic Escherichia coli Argue for Its Use to Treat Oropharyngeal Colonization and Prevent Ventilator-Associated Pneumonia.

OBJECTIVE: In the context of increasing microbial resistance and limited new antimicrobials, we aimed to study the antimicrobial effects of cranberry proanthocyanidin extracts on Escherichia coli growth, adhesion to epithelial cells, and lung infection. DESIGN: Experimental in vitro and in vivo investigation. SETTING: University research laboratory. SUBJECTS: Seventy-eight 6- to 8-week-old male Balb/C mice. INTERVENTIONS: In vitro, the effect of increasing concentrations of cranberry proanthocyanidin on bacterial growth of different clinical E. coli isolates was evaluated. Ex vivo, adhesion of E. coli to fresh human buccal epithelial cells was measured in the presence or absence of cranberry proanthocyanidin using microscopy. In vivo, lung bacterial count, pulmonary immune response (neutrophil murine chemokine keratinocyte-derived cytokine measurement and polymorphonuclear recruitment in bronchoalveolar lavage fluid), and lethality were evaluated in a pneumonia mouse model with E. coli precultured with or without cranberry proanthocyanidin. E. coli isolates originated from ventilated ICU patients with respiratory tract colonization or ventilator- associated pneumonia. They differed in number of virulence genes. MEASUREMENTS AND MAIN RESULTS: A significant inhibition of bacterial growth was observed with increasing concentration of cranberry proanthocyanidin, affecting both time to maximal growth and maximal growth rate (p<0.0001 for both). The minimal concentration at which this effect occurred was 250 µg/mL. Cranberry proanthocyanidin significantly reduced E. coli adhesion to fresh buccal epithelial cells by up to 80% (p<0.001). Bacterial counts in homogenized lungs and bronchoalveolar lavage fluid were decreased after cranberry proanthocyanidin exposition (p<0.05 and p<0.01, respectively). Cranberry proanthocyanidin also decreased KC concentrations and polymorphonuclear cell recruitment in bronchoalveolar lavage fluid (p<0.05 for both). At identical inoculum, mortality was reduced by more than half in mice inoculated with E. coli exposed to cranberry proanthocyanidin (p<0.01). CONCLUSION: Cranberry proanthocyanidins exhibit potent effects on growth, adhesion, and virulence of oropharyngeal and lung isolates of E. coli, suggesting that cranberry proanthocyanidin could be of clinical interest to reduce oropharyngeal colonization and prevent lung infection.