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Aims To determine the prognosis of patients treated for infective endocarditis (IE) according to their healthcare pathway. To assess how the ESC guidelines are implemented concerning the performance of transoesophageal echocardiography, the use of antibiotic therapy, and the performance of valve surgery; and to compare the epidemiological profile of IE according to the type of centres in which the patients are hospitalized. Methods and results In a prospective multicentric study including 22 hospitals in the South-East of France, 342 patients were classified into three groups according to their healthcare pathway: 119 patients diagnosed and taken care entirely in a reference centre or hospital with cardiac surgery [Referral Center (RC) group], 111 patients diagnosed and initially taken care in a non-RC (NRC), then referred in a centre including cardiac surgery [transferred to the Referral Center (TRC) group] and 112 patients totally taken care in the NRC (NRC group). One-year mortality was 26% (88 deaths) and was not significantly different between Groups 1 and 2 (20 vs. 21%, P = 0.83). Patients in the NRC group had a higher mortality (37%) compared with patients in the RC and TRC groups (P Conclusion Prognosis of patients with IE is influenced by their healthcare pathway. Patients treated exclusively in NRC have a worse prognosis than patients treated in referral or surgical centres.

International audience; Purpose: Duration of antibiotic therapy for ventilator-associated pneumonia (VAP) due to non-fermenting Gram-negative bacilli (NF-GNB), including Pseudomonas aeruginosa (PA) remains uncertain. We aimed to assess the non-inferiority of a short duration of antibiotics (8 days) vs. prolonged antibiotic therapy (15 days) in VAP due to PA (PA-VAP).Methods: We conducted a nationwide, randomized, open-labeled, multicenter, non-inferiority trial to evaluate optimal duration of antibiotic treatment in PA-VAP. Eligible patients were adults with diagnosis of PA-VAP and randomly assigned in 1:1 ratio to receive a short-duration treatment (8 days) or a long-duration treatment (15 days). A pre-specified analysis was used to assess a composite endpoint combining mortality and PA-VAP recurrence rate during hospitalization in the intensive care unit (ICU) within 90 days.Results: The study was stopped after 24 months due to slow inclusion rate. In intention-to-treat population (n = 186), the percentage of patients who reached the composite endpoint was 25.5% (N = 25/98) in the 15-day group versus 35.2% (N = 31/88) in the 8-day group (difference 9.7%, 90% confidence interval (CI) -1.9%-21.2%). The percentage of recurrence of PA-VAP during the ICU stay was 9.2% in the 15-day group versus 17% in the 8-day group. The two groups had similar median days of mechanical ventilation, of ICU stay, number of extra pulmonary infections and acquisition of multidrug-resistant (MDR) pathogens during ICU stay.Conclusions: Our study failed to show the non-inferiority of a short duration of antibiotics in the treatment of PA-VAP, compared to a long duration. The short duration strategy may be associated to an increase of PA-VAP recurrence. However, the lack of power limits the interpretation of this study.

Pseudomonas aeruginosa, an opportunistic Gram-negative pathogen, is a leading cause of bacteremia with a high mortality rate. We recently reported that P. aeruginosa forms a persister-like sub-population of evaders in human plasma. Here, using a gain-of-function transposon sequencing (Tn-seq) screen in plasma, we identified and validated previously unknown factors affecting bacterial persistence in plasma. Among them, we identified a small periplasmic protein, named SrgA, whose expression leads to up to a 100-fold increase in resistance to killing. Additionally, mutants in pur and bio genes displayed higher tolerance and persistence, respectively. Analysis of several steps of the complement cascade and exposure to an outer-membrane-impermeable drug, nisin, suggested that the mutants impede membrane attack complex (MAC) activity per se. Electron microscopy combined with energy-dispersive X-ray spectroscopy (EDX) revealed the formation of polyphosphate (polyP) granules upon incubation in plasma of different size in purD and wild-type strains, implying the bacterial response to a stress signal. Indeed, inactivation of ppk genes encoding polyP-generating enzymes lead to significant elimination of persisting bacteria from plasma. Through this study, we shed light on a complex P. aeruginosa response to the plasma conditions and discovered the multifactorial origin of bacterial resilience to MAC-induced killing.

Objectives: To identifyHaemophilus species and characterise the antimicrobial susceptibility of isolates from patients with respiratory tract infections (RTIs) in Cameroon. Methods: Isolates (n = 95) were from patients with RTIs obtained from two hospitals in Yaoundé, Cameroon. Isolates were identified by biochemical assay, a polymerase chain reaction (PCR)-based method, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF), and whole genome sequencing. Antibiotic minimum inhibitory concentrations were determined by E-test. Results: Haemophilus influenzae (H. influenzae) was the most prevalent species, varying from 76.8 to 84.2% according to the different methods. The isolates were mainly non-typeable (n = 70, 96%). Three H. influenzae isolates were capsulated (b, e and f). The isolates were genetically diverse and 40 unique sequence types were identified, including 11 new ones. Resistance to ampicillin was observed among 52 of 94 (55.3%), and 14 of the 52 (26.9%) produced TEM-1 β-lactamase. PBP3 mutations occurred in 40 of 52 (76.9%) ampicillin-resistant isolates. Eleven isolates were chloramphenicol-resistant, with eight of 10 (80%) producing chloramphenicol acetyltransferase. Four Haemophilus isolates were rifampicin-resistant, with two mutations in rpoB gene. Five isolates were ciprofloxacin-resistant and harboured mutations in the quinolone-resistance-determining regions of gyrA and parC genes. Conclusion: TheH. influenzae isolates were highly diverse and showed high levels of antibiotic resistance. H. influenzae serotype b is still circulating in the post-vaccination era.

International audience; A local outbreak caused by Neisseria meningitidis occurred in the migration camp in the Greek island of Lesbos during January-February 2020 (4 of 5 cases). In total, 5 samples positive for N. meningitidis were further investigated for sero-/genogroup, PorA, and WGS analysis. MenB was found among 3 cases, while in two cases, MenY was identified. WGS analysis and antibiotic susceptibility testing on the 2 culture positive MenB samples showed the new ST-3129, ciprofloxacin-resistant clone was circulating among the immigrants in the aforementioned camp. This is the first report of ciprofloxacin resistance in Greece.

Background There is a level-1 evidence indicating that postoperative antibiotics are unnecessary following cholecystectomy for grade I or II acute calculous cholecystitis (ACC). We wanted to evaluate the applications of this recommendation in clinical practice four years after the original publication in ABCAL-participating centers. Methods A retrospective analysis of patients operated for grade I or II ACC from January to December 2016 in ABCAL-participating centers was performed. Inclusion criteria were the same as for the ABCAL-study. The primary endpoint was the postoperative antibiotic administration rate. The secondary endpoints were postoperative outcomes. Results Of the 283 patients included, 64% received postoperative antibiotics. Only 19% received antibiotics after POD1. The perioperative outcomes were similar between those that did or did not receive antibiotics after POD1. The median [range] length of stay was significantly shorter in patients who did not receive postoperative antibiotics (4 days [1–20]) compared to the others (6 days [1–50], p > 0.001). Conclusion Despite strong recommendations included in the Tokyo 2018 guidelines, the results of the ABCAL-study are poorly applied even if the absence of postoperative antibiotics has no impact on morbidity. It is important to stress that postoperative antibiotics are not necessary after cholecystectomy for grade I or II ACC.

Improvements in cost and speed of next generation sequencing (NGS) have provided a new pathway for delivering disease diagnosis, molecular typing, and detection of antimicrobial resistance (AMR). Numerous published methods and protocols exist, but a lack of harmonisation has hampered meaningful comparisons between results produced by different methods/protocols vital for global genomic diagnostics and surveillance. As an exemplar, this study evaluated the sensitivity and specificity of five well-established in-silico AMR detection software where the genotype results produced from running a panel of 436 Escherichia coli were compared to their AMR phenotypes, with the latter used as gold-standard. The pipelines exploited previously known genotype–phenotype associations. No significant differences in software performance were observed. As a consequence, efforts to harmonise AMR predictions from sequence data should focus on: (1) establishing universal minimum to assess performance thresholds (e.g. a control isolate panel, minimum sensitivity/specificity thresholds); (2) standardising AMR gene identifiers in reference databases and gene nomenclature; (3) producing consistent genotype/phenotype correlations. The study also revealed limitations of in-silico technology on detecting resistance to certain antimicrobials due to lack of specific fine-tuning options in bioinformatics tool or a lack of representation of resistance mechanisms in reference databases. Lastly, we noted user friendliness of tools was also an important consideration. Therefore, our recommendations are timely for widespread standardisation of bioinformatics for genomic diagnostics and surveillance globally.

International audience; In 2016, the Austrian Agency for Health and Food Safety started a pilot project to investigate antimicrobial resistance in surface water. Here we report on the characterisation of carbapenem resistant and ESBL-producing K. pneumoniae isolates from Austrian river water samples compared to 95 clinical isolates recently obtained in Austrian hospitals. Ten water samples were taken from four main rivers, collected upstream and downstream of major cities in 2016. For subtyping and comparison, public core genome multi locus sequence typing (cgMLST) schemes were used. The presence of AMR genes, virulence genes and plasmids was extracted from whole genome sequence (WGS) data. In total three ESBL-producing strains and two carbapenem resistant strains were isolated. WGS based comparison of these five water isolates to 95 clinical isolates identified three clusters. Cluster 1 (ST11) and cluster 2 (ST985) consisted of doublets of carbapenem resistant strains (one water and one clinical isolate each). Cluster 3 (ST405) consisted of three ESBL-producing strains isolated from one water sample and two clinical specimens. The cities, in which patient isolates of cluster 2 and 3 were collected, were in concordance with the water sampling locations downstream from these cities. The genetic concordance between isolates from river water samples and patient isolates raises concerns regarding the release of wastewater treatment plant effluents into surface water. From a public health perspective these findings demand attention and strategies are required to minimize the spread of multiresistant strains to the environment.

Digestate produced by agricultural biogas plants (BGPs) may contain pathogenic bacteria. Among them, Clostridium perfringens deserves particular attention due to its ability to grow under anaerobic conditions and persist in amended soil. The aim of this study was to examine the potential pathogenicity and the antimicrobial resistance of C. perfringens in manure and digestate collected from three agricultural biogas plants (BGPs). A total of 157 isolates (92 from manure, 65 from digestate) were screened for genes encoding seven toxins (cpa, cpb, etx, iapcpe, netB, and cpb2). The 138 cpa positive isolates were then screened for tetA(P), tetB(P), tet(M), and erm(Q) genes and tested for antimicrobial susceptibility. The toxinotypes identified in both manure and digestate were type A (78.3% of the isolates), type G (16.7%), type C (3.6%), and type D (1.4%), whereas none of the isolates were type F. Moreover, half of the isolates carried the cpb2 gene. The overall prevalence of tetA(P) gene alone, tetA(P)-tetB(P) genes, and erm(Q) gene was 31.9, 34.8, and 6.5%, respectively. None of the isolates harbored the tet(M) gene. Multiple antimicrobial resistant isolates were found in samples that were collected from all the manure and digestates. Among them, 12.3% were highly resistant to some of the antibiotics tested, especially to clindamycin (MIC &ge, 16 &micro, g/mL) and tilmicosin (MIC &gt, 64 &micro, g/mL). Some isolates were highly resistant to antibiotics used in human medicine, including vancomycin (MIC &gt, 8 &micro, g/mL) and imipenem (MIC &gt, g/mL). These results suggest that digestate may be a carrier of the virulent and multidrug resistant C. perfringens.

International audience; The aim of this paper is to propose an approach based on preference learning for building a model that represents the closest possible experts reasoning to provide recommendations. We apply this method to antibiotherapy in primary care. The preference model was learned from the recommendations and from a database describing the domain.

International audience; Background. Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-Kp) has emerged globally over the last decade as a major nosocomial pathogen that threatens patient care. These highly resistant bacteria are mostly associated with a single Kp clonal group, CG258, but the reasons for its host and hospital adaptation remain largely unknown. Methods. We analyzed the in vivo evolution of a colistin-resistant KPC-Kp CG258 strain that contaminated a patient following an endoscopy and was responsible for a fatal bacteremia 4.5 years later. Whole-genome sequencing was performed on 17 KPC-Kp isolates from this patient; single-nucleotide polymorphisms were analyzed and their implication in antimicrobial resistance and bacterial host adaptation investigated. Results. The patient KPC-Kp strain diversified over 4.5 years at a rate of 7.5 substitutions per genome per year, resulting in broad phenotypic modifications. After 2 years of carriage, all isolates restored susceptibility to colistin. Higher expression of the fimbriae conferred the ability to produce more biofilm, and the isolate responsible for a bacteremia grew in human serum. The convergent mutations occurring in specific pathways, such as the respiratory chain and the cell envelope, revealed a complex long-term adaptation of KPC-Kp. Conclusions. Broad genomic and phenotypic diversification and the parallel selection of pathoadaptive mutations might contribute to long-term carriage and virulence of KPC-Kp CG258 strains and to the dissemination of this clone.

International audience; The emergence of antibiotic-resistant Yersinia pestis strains represents a public health concern. Two antibiotic-resistant Y. pestis strains isolated from Madagascar have been previously identified and characterised. Both strains carried conjugative plasmids that conferred resistance to streptomycin or to multiple antibacterial drugs, respectively. Here we characterised a novel Y. pestis strain (IP2180H) that exhibited resistance to doxycycline. This strain was isolated from a rat in Antananarivo (Madagascar) in 1998. Resistance was carried by a conjugative plasmid (pIP2180H) homologous to pB71 from Salmonella enterica. The plasmid of the previously identified streptomycin-resistant Y. pestis strain was also sequenced and it was found that the three antibiotic resistance Y. pestis plasmids sequenced until now are genetically unrelated and are also unrelated to multidrug resistance plasmids from the phylogenetically close bacterial species Yersinia pseudotuberculosis. The fact that the three antibiotic-resistant Malagasy Y. pestis strains were isolated from different hosts, at different times, from distant locations, and carried unrelated plasmids indicates independent horizontal acquisition of genetic material and further demonstrates the capacity of Y. pestis to acquire antibiotic resistance plasmids under natural conditions. Since these resistance plasmids can frequently carry or easily trap antibiotic resistance cassettes, the emergence of new multidrug-resistant Y. pestis strains may be expected and would represent a major health threat.

International audience; In this study, we aimed to decipher the natural resistance mechanisms of mycobacteria against novel compounds isolated by whole-cell-based high-throughput screening (HTS). We identified active compounds using Mycobacterium aurum. Further analyses were performed to determine the resistance mechanism of M. smegmatis against one hit, 3-bromo-N-(5-nitrothiazol-2-yl)-4-propoxybenzamide (3), which turned out to be an analog of the drug nitazoxanide (1). We found that the repression of the gene nfnB coding for the nitroreductase NfnB was responsible for the natural resistance of M. smegmatis against 3. The overexpression of nfnB resulted in sensitivity of M. smegmatis to 3. This compound must be metabolized into hydroxylamine intermediate for exhibiting antibacterial activity. Thus, we describe, for the first time, the activity of a mycobacterial nitroreductase against 1 analogs, highlighting the differences in the metabolism of nitro compounds among mycobacterial species and emphasizing the potential of nitro drugs as antibacterials in various bacterial species.

bahar tokman, hrisi/0000-0002-2205-5120 WOS:000525325200020 PubMed ID: 31634565 Objectives: Studies on the antimicrobial susceptibility profile of anaerobic bacteria are underrepresented in the literature. Within this study we aim to give an extensive overview of the differences in antimicrobial susceptibility profiles between different European and surrounding countries. Methods: Minimal inhibitory concentration (MIC) data of different antibiotics were collected from 10 participating laboratories, representing an equal number of countries. All MIC's were determined using Etest, according to the protocol used by the participating laboratory. Anaerobic genera represented by at least 10 clinical isolates were included in the study. Results: Each country tested different antibiotics, sometimes depending on the kind of infection and/or the anaerobic species isolated. All countries tested clindamycin and metronidazole. Resistance rates differed remarkably between the different countries. Especially in Kuwait, resistance was high for all tested antibiotics. Unexpected metronidazole resistance was observed for Finegoldia magna isolates, Peptoniphilus isolates and Eggerthella lenta isolates. Conclusions: Due to the extensive differences in antimicrobial susceptibility profile of anaerobic bacteria isolated within different countries, we strongly recommend to perform this kind of study on a regular basis. (C) 2019 The Authors. Published by Elsevier Ltd.

International audience; OBJECTIVE:We aimed to assess medical practices of French infectious disease specialists or any other relevant physicians related to the management of non-necrotizing cellulitis (NNC).METHODS:We sent an online questionnaire to members of the French Infectious Diseases Society (SPILF) mailing list in September 2015.RESULTS:A total of 108 specialists took part in the survey and 10% (11/107) declared to always admit NNC patients to hospital. As for the others, 18% declared to admit patients in more than 80% of cases, 49% in 50-80% of cases, 26% in 20-50% of cases, and 7% in less than 20% of cases. The most frequent criteria for hospital admission were severe sepsis/septic shock (99%), poor social conditions (99%), rapid extension of skin lesions (93%), high level of pain (86%), and failure of first-line antibiotic therapy (84%). Participants mentioned similar criteria for reasons to initiate the intravenous (IV) antibiotic therapy. Fifty-three percent of respondents declared initiating antibiotic therapy using the IV route in more than 80% of cases. Physicians declared that the usual antibiotic therapy duration were 15 days (3%).CONCLUSION:Criteria for hospital admission and use of the IV route for antibiotic therapy as well as optimal treatment duration in patients presenting with NNC need to be detailed in guidelines and evaluated in prospective studies.

We surveyed European medical schools regarding teaching of prudent antibiotic prescribing in the undergraduate curriculum. We performed a cross-sectional survey in 13 European countries (Belgium, Croatia, Denmark, France, Germany, Italy, Netherlands, Norway, Serbia, Slovenia, Spain, Switzerland, United Kingdom) in 2013. Proportional sampling was used, resulting in the selection of two to four medical schools per country. A standardized questionnaire based on literature review and validated by a panel of experts was sent to lecturers in infectious diseases, medical microbiology and clinical pharmacology. In-depth interviews were conducted with four lecturers. Thirty-five of 37 medical schools were included in the study. Prudent antibiotic use principles were taught in all but one medical school, but only four of 13 countries had a national programme. Interactive teaching formats were used less frequently than passive formats. The teaching was mandatory for 53% of the courses and started before clinical training in 71%. We observed wide variations in exposure of students to important principles of prudent antibiotic use among countries and within the same country. Some major principles were poorly covered (e.g. reassessment and duration of antibiotic therapy, communication skills). Whereas 77% of the respondents fully agreed that the teaching of these principles should be prioritized, lack of time, mainly due to rigid curriculum policies, was the main reported barrier to implementation. Given the study design, these are probably optimistic results. Teaching of prudent antibiotic prescribing principles should be improved. National and European programmes for development of specific learning outcomes or competencies are urgently needed. Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved

International audience; BACKGROUND:Childhood community-acquired pneumonia is a leading cause of childhood morbidity in low-income countries. The etiologic agents are usually Staphylococcus aureus, Streptococcus pneumoniae and Mycoplasma pneumoniae. M. pneumoniae was recognized as a cofactor in asthmatic disease. High asthma prevalence was reported in Madagascar. Our aim was to clarify the prevalence of M. pneumoniae infection in this country and its relationship with asthma.METHODS:A prospective study was conducted in 351 children (from 2 to 16 years of age) from January 2012 to December 2014. According to the clinical symptoms, children were enrolled in 3 groups: "control group" (CG, n = 106), "asthma group" (n = 129) and "pneumonia group" (n = 116). The IgG and IgM M. pneumoniae status was evaluated by an enzyme-linked immunosorbent assay. Clinical signs of infection, socioeconomic data and antimicrobial treatment were recorded.RESULTS:The overall prevalence of M. pneumoniae infection was 18.2%. The multivariate analysis demonstrated that M. pneumoniae infection was significantly more frequent in the CG [pneumonia group vs. CG: odds ratio = 0.45 (0.21-0.91), P = 0.037 and asthma group vs. CG: odds ratio = 0.39 (0.18-0.87), P = 0.021]. The C-reactive protein value was significantly higher in children with M. pneumonia-positive serology (85 vs. 61 mg/L, P = 0.03). Of note, 99 (41%) children received antibiotics before attending.CONCLUSIONS:We report a prevalence of 18.2% for M. pneumoniae infection in children in Madagascar. The prevalence of M. pneumoniae infection was higher in the control patients than in asthmatic ones.

International audience; Significant alterations in the pharmacokinetics (PK) of antimicrobials have been reported in critically ill patients. We describe PK parameters of imipenem in intensive care unit (ICU) patients with suspected ventilator-associated pneumonia and evaluate several dosage regimens. This French multicentre, prospective, open-label study was conducted in ICU patients with a presumptive diagnosis of ventilator-associated pneumonia caused by Gram-negative bacilli, who empirically received imipenem intravenously every 8 h. Plasma imipenem concentrations were measured during the fourth imipenem infusion using six samples (trough, 0.5, 1, 2, 5 and 8 h). Data were analysed with a population approach using the stochastic approximation expectation maximization algorithm in Monolix 4.2. A Monte Carlo simulation was performed to evaluate the following six dosage regimens: 500, 750 or 1000 mg with administration every 6 or 8 h. The pharmacodynamic target was defined as the probability of achieving a fractional time above the minimal inhibitory concentration (MIC) of >40%. Fifty-one patients were included in the PK analysis. Imipenem concentration data were best described by a two-compartment model with three covariates (creatinine clearance, total bodyweight and serum albumin). Estimated clearance (between-subject variability) was 13.2 l h(-1) (38%) and estimated central volume 20.4 l (31%). At an MIC of 4 μg ml(-1) , the probability of achieving 40% fractional time > MIC was 91.8% for 0.5 h infusions of 750 mg every 6 h, 86.0% for 1000 mg every 8 h and 96.9% for 1000 mg every 6 h. This population PK model accurately estimated imipenem concentrations in ICU patients. The simulation showed that for these patients, the best dosage regimen of imipenem is 750 mg every 6 h and not 1000 mg every 8 h.

International audience; Antimicrobial resistance (AMR), associated with a lack of new antibiotics, is a major threat. Some countries have been able to contain resistance, but in most countries the numbers of antibiotic-resistant bacteria continue to increase, along with antibiotic consumption by humans and animals. AMR is a global issue, and concerns all decision-makers worldwide. Some initiatives have been undertaken in the last 15 years, in particular by the WHO, the European Centre for Disease Prevention and Control, and the CDC, but those initiatives were partial and poorly implemented, without coordination. Very recently, some important initiatives have been implemented by the WHO. Since 2009, a US and European joint task force, the Trans-Atlantic Task Force on Antibiotic Resistance, has been working on common recommendations. At a national level, some important initiatives have been implemented, in particular in European countries and in the USA. The Chennai declaration, in India, is also a good example of a multidisciplinary and national initiative that was highly political. Finally, several non-governmental non-profit organizations are also very active, and have helped to raise awareness about the problem of AMR. In the future, this global issue will need political involvement and strong cooperation between countries and between international agencies.

International audience; Peptidoglycan is an essential component of the bacterial cell wall, and enzymes involved in its biosynthesis represent validated targets for antibacterial drug discovery. MurF catalyzes the final intracellular peptidoglycan biosynthesis step: the addition of D-Ala-D-Ala to the nucleotide precursor UDP-MurNAc-L-Ala-γ-D-Glu-meso-DAP (or L-Lys). As MurF has no human counterpart, it represents an attractive target for the development of new antibacterial drugs. Using recently published cyanothiophene inhibitors of MurF from Streptococcus pneumoniae as a starting point, we designed and synthesized a series of structurally related derivatives and investigated their inhibition of MurF enzymes from different bacterial species. Systematic structural modifications of the parent compounds resulted in a series of nanomolar inhibitors of MurF from S. pneumoniae and micromolar inhibitors of MurF from Escherichia coli and Staphylococcus aureus. Some of the inhibitors also show antibacterial activity against S. pneumoniae R6. These findings, together with two new co-crystal structures, represent an excellent starting point for further optimization toward effective novel antibacterials.

International audience; The human pregnane X receptor (PXR) is a ligand-regulated transcription factor belonging to the nuclear receptor superfamily. PXR is activated by a large, structurally diverse, set of endogenous and xenobiotic compounds and coordinates the expression of genes central to metabolism and excretion of potentially harmful chemicals and therapeutic drugs in humans. Walrycin A is a novel antibacterial compound targeting the WalK/WalR two-component signal transduction system of Gram (+) bacteria. Here, we report that, in hepatoma cells, walrycin A potently activates a gene set known to be regulated by the xenobiotic sensor PXR. Walrycin A was as efficient as the reference PXR agonist rifampicin to activate PXR in a transactivation assay at noncytotoxic concentrations. Using a limited proteolysis assay, we show that walrycin A induces conformational changes at a concentration which correlates with walrycin A ability to enhance the expression of prototypic target genes, suggesting that walrycin A interacts with PXR. The activation of the canonical human PXR target gene CYP3A4 by walrycin A is dose and PXR dependent. Finally, in silico docking experiments suggest that the walrycin A oxidation product Russig's blue is the actual ligand for PXR. Taken together, these results identify walrycin A as a novel human PXR activator.

International audience; Quaternary ammonium compounds (QACs) are cationic surfactants used as preservatives and environmental disinfectants. Limited data are available regarding the effect of QACs in the clinical setting. We performed a prospective cohort study in 153 patients with Escherichia coli bacteraemia from February to September 2008 at University Hospital in Rennes. The minimum inhibitory concentrations (MICs) of antibiotics and QACs alkyldimethylbenzylammonium chloride (ADBAC) and didecyldimethylammonium chloride (DDAC) were determined by the agar dilution method. The capacity of biofilm production was assayed using the Crystal Violet method, and mutation frequencies by measuring the capacity of strains to generate resistance to rifampicin. Logistic regression analysis showed that one of the significant factors related to low MICs for ADBAC (≤16 mg/L) and DDAC (≤8 mg/L), was cotrimoxazole susceptibility (odds ratio: 3.72; 95% confidence interval: 1.22-11.24; P=0.02 and OR: 3.61; 95% CI: 1.56-7.56; P

International audience; A collection of 3-substituted indole derivatives was prepared using nucleophilic addition of indoles to nitrones. The compounds were then tested for their antibacterial activity against almost thirty bacterial strains representative of common human pathogens. Two types of indolic molecules inhibit the growth of Staphylococcus aureus, including MRSA and VISA strains, with MIC values ranging from 8 to 16 mg/L.

International audience; The use of fluoroquinolone (FQ) as first line therapy for typhoid fever should be reconsidered because of the emergence of Salmonella Typhi and Paratyphi A strains with decreased susceptibility to FQ, mainly from Asia. Relapse can occur when ciprofloxacin MIC is over 0.12 mg/l, as illustrated by our case report. Azithromycin can be used successfully for patients infected with reduced ciprofloxacin susceptibility isolates. Literature review led us to suggest a new therapeutic strategy for uncomplicated typhoid fever, the antibiotic was chosen according to nalidixic acid susceptibility and ciprofloxacin MIC of the strain. High-dose intravenous ceftriaxone (4 g per day) is always efficient in first line therapy. Depending on FQ susceptibility testing results, it is relayed by oral therapy with a FQ (ciprofloxacin 500 mg bid for 7 days) if the isolate has maintained susceptibility, or azithromycin (1 g first day and 500 mg per day, 7 days) if the isolate is resistant to nalidixic acid or has a ciprofloxacin MIC superior to 0.12 mg/l.; La place des fluoroquinolones (FQ) dans le traitement de première intention des fièvres typhoïdes (FT) doit être remise en question du fait de l’émergence de souches de Salmonella enterica serovar Typhi et Paratyphi A de sensibilité diminuée aux FQ en provenance d’Asie du sud-est. Des rechutes peuvent survenir quand la CMI de la ciprofloxacine est supérieure ou égale à 0,125 mg/l, comme l’illustre le cas clinique que nous rapportons. L’azithromycine a une efficacité démontrée sur les souches de sensibilité diminuée à la ciprofloxacine. À partir d’une revue de la littérature, nous proposons un nouveau schéma thérapeutique des FT non compliquées, où l’antibiothérapie est guidée par la sensibilité à l’acide nalidixique et la CMI de la ciprofloxacine de la souche. La ceftriaxone intraveineuse à forte dose (4 g/24 h) est toujours efficace en première intention ; elle est initiée dans l’attente des données de sensibilité de la souche. Un relais par voie orale est pris avec une FQ (ciprofloxacine 500 mg deux fois par jour, sept jours) en cas de sensibilité conservée, ou l’azithromycine (1 g le premier jour, puis 500 mg par jour, sept jours) en cas de résistance à l’acide nalidixique ou de CMI de la ciprofloxacine supérieure ou égale à 0,125 mg/l.

International audience; Chitosan, an N-deacetylated derivative of chitin, has attracted much attention as an antimicrobial agent against fungi, bacteria, and viruses. Chitosanases, the glycoside hydrolases responsible for chitosan depolymerisation, are intensively studied as tools for biotechnological transformation of chitosan. The chitosanase CsnA (SCO0677) from Streptomyces coelicolor A3(2) was purified and characterized. CsnA belongs to the GH46 family of glycoside hydrolases. However, it is secreted efficiently by the Tat translocation pathway despite its similarity to the well-studied chitosanase from Streptomyces sp. N174 (CsnN174), which is preferentially secreted through the Sec pathway. Melting point determination, however, revealed substantial differences between these chitosanases, both in the absence and in the presence of chitosan. We further assessed the role of CsnA as a potential protective enzyme against the antimicrobial effect of chitosan. A Streptomyces lividans TK24 strain in which the csnA gene was inactivated by gene disruption was more sensitive to chitosan than the wild-type strain or a chitosanase-overproducing strain. This is the first genetic evidence for the involvement of chitosanases in the protection of bacteria against the antimicrobial effect of chitosan.

International audience

International audience; As the association of marine animals with bacteria has become more commonly recognized, researchers have increasingly questioned whether these animals actually produce many of the bioactive compounds originally isolated from them. Bacteriocins, ribosomally synthesized antibiotic peptides, constitute one of the most potent weapons to fight against pathogen infections. Indeed, bacteriocinogenic bacteria may prevent pathogen dissemination by occupying the same ecological niche. Bacteriocinogenic strains associated with marine animals are a relevant source for isolation of probiotics. This review draws up an inventory of the marine bacteriocinogenic strains isolated from animal-associated microbial communities, known to date. Bacteriocin-like inhibitory substances (BLIS) and fully-characterized bacteriocins are described. Finally, their applications as probiotics in aquaculture are discussed.

There are concerns that more extensive application of disinfectants in the food industry could result in increased resistance of bacteria to antibiotics and that therapeutic failure could ensue. This paper highlights the differences in application and mode of action between antibiotics in human or animal medicine and disinfectants in the food industry. It describes the completely different methods used to determine in-use concentrations in the two contexts. It points out that the minimum inhibitory concentration (MIC) is never the concentration at which disinfectants should be applied. It also discusses erroneous conclusions that may be drawn when the failure of therapy or disinfection is attributed to intrinsic properties of the molecules rather than to misuse of antibiotics or disinfectants. The paper suggests that the intended meaning of the word "resistance" be carefully defined in scientific articles with due reference to the measurement mentioned in the abstract and possibly reflected in the title. It also suggests that in matters of disinfection the word "resistance" be preferred when the phenomenon being studied is killing and "tolerance" when it is the adaptation to inhibitory concentrations.

The aim of this study was to examine the dynamics of the development of resistance in fecal Escherichia coli populations during treatment with ampicillin for 7 days in pigs. Before treatment, only 6% of the isolates were ampicillin resistant, whereas more than 90% of the isolates were resistant after days 4 and 7 of treatment. Ampicillin-resistant E. coli isolates were mainly multiresistant, and 53% of the isolates from the treated pigs had one phenotype that included resistance to six antibiotics (ampicillin, chloramphenicol, sulfonamides, tetracycline, trimethoprim, and streptomycin) at day 7. Determination of the frequency of the four phylogenetic groups showed that there was a shift in the E. coli population in ampicillin-treated pigs; before treatment 75% of the isolates belonged to phylogroup B1, whereas at day 7 85% of the isolates belonged to phylogroup A. Pulsed-field gel electrophoresis (PFGE) typing revealed that ampicillin treatment selected ampicillin-resistant isolates with genotypes which were present before treatment. Comparison of antimicrobial phenotypes and PFGE genotypes showed that resistance traits were disseminated by vertical transmission through defined strains. One PFGE genotype, associated with the six-antibiotic-resistant phenotype and including a specific combination of resistance determinants, was predominant among the ampicillin-resistant strains before treatment and during treatment. These data indicate that ampicillin administration selected various ampicillin-resistant isolates that were present in the digestive tract before any treatment and that E. coli isolates belonging to one specific PFGE genotype encoding resistance to six antibiotics became the predominant strains as soon as ampicillin was present in the digestive tract.

International audience; Lung administration of antibiotics by nebulization is promising for improving treatment efficiency for pulmonary infections, as it increases drug concentration at sites of infection while minimizing systemic side effects. For poorly soluble molecules like rifampicin, cyclodextrins (CD) may improve lung delivery by permitting higher dosing. For this purpose, we investigated rifampicin-CD complexes in terms of rifampicin apparent solubility enhancement, effect on in vitro permeability on Calu-3 broncho-alveolar cells, effect on in vitro antibacterial activity against Acinetobacter baumannii and nebulization characteristics measured by NGI cascade impactor. Complexation efficiency between rifampicin and methylated beta-cyclodextrin (RAMEB) or hydroxypropyl-beta-cyclodextrin (HPbetaCD) was pH-dependent, involving the piperazin group. Rifampicin phase solubility diagrams constructed at pH 9 showed an A(L)-type curve for RAMEB and a B(S)-type for HPbetaCD. Stability constants calculated for a 1:1 molar ratio of CD/rifampicin were 73.4 +/- 8.2 M(-1) for RAMEB and 68.5 +/- 5.2 M(-1) for HPbetaCD. Complexes with RAMEB or HPbetaCD increased 22 times and 7.6 times respectively the apparent solubility of rifampicin and were found to be satisfactorily stable for 2 days when diluted in a solution at physiological pH. The nebulization of the complex solution created droplets in size range compatible with pulmonary deposition. Furthermore, the presence of HPbetaCD decreased the MMAD of the aerosolized droplets. Activity of RAMEB and HPbetaCD complexes measured by the total rifampicin MIC against A. baumannii was similar or lower to free rifampicin MIC respectively. Complexation did not alter the rifampicin permeability in the timescale of 1h as evaluated with a Calu-3 epithelial cell model, but acted as a reservoir for rifampicin. In conclusion, this work reports that CDs can be used as vectors for pulmonary nebulization to increase the amount of active rifampicin and optimize its lung pharmacokinetic profile.

OBJECTIVE—Diabetes and obesity are characterized by a low-grade inflammation whose molecular origin is unknown. We previously determined, first, that metabolic endotoxemia controls the inflammatory tone, body weight gain, and diabetes, and second, that high-fat feeding modulates gut microbiota and the plasma concentration of lipopolysaccharide (LPS), i.e., metabolic endotoxemia. Therefore, it remained to demonstrate whether changes in gut microbiota control the occurrence of metabolic diseases. RESEARCH DESIGN AND METHODS—We changed gut microbiota by means of antibiotic treatment to demonstrate, first, that changes in gut microbiota could be responsible for the control of metabolic endotoxemia, the low-grade inflammation, obesity, and type 2 diabetes and, second, to provide some mechanisms responsible for such effect. RESULTS—We found that changes of gut microbiota induced by an antibiotic treatment reduced metabolic endotoxemia and the cecal content of LPS in both high-fat–fed and ob/ob mice. This effect was correlated with reduced glucose intolerance, body weight gain, fat mass development, lower inflammation, oxidative stress, and macrophage infiltration marker mRNA expression in visceral adipose tissue. Importantly, high-fat feeding strongly increased intestinal permeability and reduced the expression of genes coding for proteins of the tight junctions. Furthermore, the absence of CD14 in ob/ob CD14−/− mutant mice mimicked the metabolic and inflammatory effects of antibiotics. CONCLUSIONS—This new finding demonstrates that changes in gut microbiota controls metabolic endotoxemia, inflammation, and associated disorders by a mechanism that could increase intestinal permeability. It would thus be useful to develop strategies for changing gut microbiota to control, intestinal permeability, metabolic endotoxemia, and associated disorders.

Purpose of the study The aim of this study was to evaluate the in vitro activity of tigecycline and other comparator agents against bacterial strains isolated from diabetic foot infections (DFI). Patients and methods All diabetic patients hospitalized for a first episode of DFI (stage 2 to 4, according to the International Working Group of Diabetic Foot classification) were selected in Nimes University hospital between January 2005 and June 2006. MICs were determined using custom broth microdilution panels against bacterial strains isolated from foot samples. Results Three hundred fifteen strains were studied. Tigecycline was active against 83.7% of all the strains especially Gram-positive cocci (97.3%) in particular methicillin-resistant Staphylococcus aureus (96%), Enterobacteriaceae (88.5%) and anaerobes (100%). Exclusively Pseudomonas aeruginosa and Proteae were not covered by this antibiotic. Conclusions Tigecycline, a new broad spectrum antimicrobial agent, is qualified to belong to the therapeutic arsenal package of complicated skin and soft tissue infections in diabetic patients after microbial documentation.

International audience; Neomycin ototoxicity and electrode insertion trauma both involve activation of the mitogen activated protein kinase (MAPK)/c-Jun-N-terminal kinase (JNK) cell death signal cascade. This article discusses mechanisms of cell death on a cell biology level (e.g. necrosis and apoptosis) and proposes the blocking of JNK signaling as a therapeutic approach for preventing the development of a permanent hearing loss that can be initiated by either neomycin ototoxicity or electrode insertion trauma. Blocking of JNK molecules incorporates the use of a peptide inhibitor (i.e. D-JNKI-1), which is specific for all three isoforms of JNK and has been demonstrated to prevent loss of hearing following either electrode insertion trauma or loss of both hearing and hair cells following exposure to an ototoxic level of neomycin. We present previously unpublished results that control for the effect of perfusate washout of aminoglycoside antibiotic by perfusion of the scala tympani with an inactive form of D-JNKI-1 peptide, i.e. JNKI-1(mut) peptide, which was not presented in the original J. Neurosci. article that tested locally delivered D-JNKI-1 peptide against both noise- and neomycin-induced hearing loss (i.e. Wang, J., Van De Water, T.R., Bonny, C., de Ribaupierre, F., Puel, J.L., Zine, A. 2003a. A peptide inhibitor of c-Jun N-terminal kinase protects against both aminoglycoside and acoustic trauma-induced auditory hair cell death and hearing loss. J. Neurosci. 23, 8596-8607). D-JNKI-1 is a cell permeable peptide that blocks JNK signaling at the level of the three JNK molecular isoforms, which when blocked prevents the increases in hearing thresholds and the loss of auditory hair cells. This unique therapeutic approach may have clinical application for preventing: (1) hearing loss caused by neomycin ototoxicity; and (2) the progressive component of electrode insertion trauma-induced hearing loss.

The bacterial RNA polymerase (RNAP) is an essential enzyme that is responsible for making RNA from a DNA template and is targeted by several antibiotics. Rifampicin was the first of such antibiotics to be described and is one of the most efficient anti-tuberculosis drugs in use. In the past five years, structural studies of bacterial RNAP and the resolution of several complexes of drugs bound to RNAP subunits have revealed molecular details of the drug-binding sites and the mechanism of drug action. This knowledge opens avenues for the development of antibiotics. Here these drugs are reviewed, together with their mechanisms and their potential interest for therapeutic applications.

International audience; Lantibiotics are antimicrobial peptides from the bacteriocin family, secreted by Gram-positive bacteria. These peptides differ from other bacteriocins by the presence of (methyl)lanthionine residues, which result from enzymatic modification of precursor peptides encoded by structural genes. Several groups of lantibiotics have been distinguished, the largest of which is the lacticin 481 group. This group consists of at least 16 members, including lacticin 481, streptococcin A-FF22, mutacin II, nukacin ISK-1, and salivaricins. We present the first review devoted to this lantibiotic group, knowledge of which has increased significantly within the last few years. After updating the group composition and defining the common properties of these lantibiotics, we highlight the most recent developments. The latter concern: transcriptional regulation of the lantibiotic genes; understanding the biosynthetic machinery, in particular the ability to perform in vitro prepeptide maturation; characterization of a novel type of immunity protein; and broad application possibilities. This group differs in many aspects from the best known lantibiotic group (nisin group), but shares properties with less-studied groups such as the mersacidin, cytolysin and lactocin S groups.

International audience; Aminoglycosides are of major importance in treating Pseudomonas aeruginosa pneumonia (PAP). However, their efficacy may be compromised by low-level resistance caused by the inducible MexXY multidrug efflux pump. In the present study, the impact of the MexXY efflux pump was investigated in vivo in an experimental model of PAP in rabbits treated with intravenous tobramycin. Three strains were used to induce PAP in rabbits: PAO1 (wild-type strain; MIC 1 mg/L), mutant 11B (mexX::Tn501; no expression of MexXY; MIC 0.5 mg/L) and mutant MutGR1 (MexZ null; constitutive expression of MexXY; MIC 2 mg/L). Five hours after inoculation, treatment with tobramycin (10 mg/kg) was implemented (peak serum concentration 30 mg/L). The animals were killed humanely 48 h after inoculation, and the residual pulmonary bacterial concentration was determined. Selection of bacteria expressing MexXY was determined by plating lung homogenates on agar plates containing antibiotic. Mean bacterial counts (log(10) CFU/g) for treated vs. untreated rabbits were 6.26 and 8.13 (p < 0.0001), 6.00 and 8.38 (p < 0.001), and 7.25 and 8.79 (p 0.04) for PAO1, 11B and MutGR1, respectively, with an overall mortality rate of 0% vs. 8.9% (p < 0.01). MexXY-overexpressing bacteria were recovered from three (21%) treated rabbits. The C(max)/MIC ratio was the parameter that was best associated with tobramycin efficacy. The bacteria overexpressing MexXY, recovered from lung, occurred with a C(max)/MIC window of 19-26. It was concluded that the experimental PAP model highlights poor tobramycin bacteriological efficacy in vivo, contrasting with survival gain, and that the contribution of the MexXY system to this low level of tobramycin efficacy is modest. Finally, this model appears to be suitable for the investigation of new anti-pseudomonal therapeutic strategies.

9 pages; International audience; Respiratory tract lesions induced by the chemical warfare agent sulfur mustard (SM) are characterized by epithelial damages associated with inflammatory cell infiltration. Here we evaluated the imbalance between gelatinase and tissue inhibitors of metalloproteinases (TIMPs), and we tested pretreatment with the protease inhibitor doxycycline. Guinea pigs were intoxicated intratracheally with SM and evaluated 24 h after exposure. Matrix metalloproteinase (MMP) gelatinase activity of bronchial lavage (BL) fluid from SM-exposed guinea pigs was high compared with controls, as shown by both zymography and biotinylated substrate degradation, whereas TIMP-1 and -2 levels by immunoblotting were similar. Extensive areas of lysis were evidenced by in situ zymography, indicating imbalance between gelatinases and inhibitors towards net proteolytic activity. Doxycycline pretreatment resulted in 1) decreased gelatinase activity (zymography, free gelatinase activity assay, and in situ zymography); 2) decreased inflammation (BL fluid cellularity and protein level); and 3) dramatic decrease in histological epithelial lesions. Our results suggest inadequate levels of TIMP to counteract increased gelatinase activity and further support a role for MMP gelatinases in SM-induced respiratory lesions. They also suggest that doxycycline may hold promise as a therapeutic tool.

International audience; Trans-translation is a process that recycles ribosomes stalled on problematic mRNAs. tmRNA, coded by the DeltassrA gene, is a major component of trans-translation. Bacteria lacking tmRNA are more sensitive to several inhibitors of protein synthesis when compared to a wild type strain. We measured bacterial growth of the DeltassrA and wild type strains in Escherichia coli in the presence of 14 antibiotics including some that do not target protein synthesis. Both the optical density of the bacterial cultures and the number of viable cells were monitored. For the ribosome-targeted antibiotics, sensitization was observed on erythromycin, chloramphenicol, kanamycin, puromycin and streptomycin. Minor or no effects were observed with clindamycin, tetracycline and spectinomycin. Surprisingly, the DeltassrA strain is more sensitive than wild type to inhibitors of cell wall synthesis: fosfomycin and ampicillin. No growth difference was observed on drugs with other target sites: ofloxacin, norfloxacin, rifampicin and trimethoprim. Sensitization to antibiotics having target sites other than the ribosome suggests that trans-translation could influence antibiotic-induced stress responses. In trans-translation-deficient bacteria, cell death is significantly enhanced by the two aminoglycosides that induce translational misreading, streptomycin and kanamycin.

BACKGROUND: This work investigates the incidence and clinical features of syphilitic uveitis in patients infected with human immunodeficiency virus (HIV). MATERIAL AND METHODS: We retrospectively reviewed syphilitic uveitis in patients coinfected with HIV that presented at a referral center between July 2001 and November 2003. RESULTS: Twelve patients (20 eyes) were included. The ocular manifestations of syphilis led to the discovery of HIV-1 seropositivity in three patients. All patients were male and homosexual. One patient has been previously treated for syphilis with benzathine penicillin G. One patient presented with anterior uveitis and 11 patients had panuveitis or posterior uveitis. Necrotizing retinitis was noted in seven eyes (35%), posterior placoid chorioretinitis in six eyes (30%) and optic nerve involvement in five eyes (25%). Of nine patients with available cerebrospinal fluid (CSF) studies, seven (77.8%) had CSF abnormalities. Eleven patients were treated with intravenous penicillin G and one with intravenous ceftriaxone sodium. One patient required a second course of antibiotics to control uveitis. Ocular inflammation decreased and visual acuity improved in all nine patients for whom follow-up was available after treatment. CONCLUSION: Manifestations of syphilitic uveitis in HIV-infected patients are multiple, with high frequencies of posterior uveitis, posterior placoid chorioretinitis, necrotizing retinitis and optic nerve involvement. Syphilitic uveitis in HIV-infected patients seems to have a more severe course and may relapse despite high-dose intravenous penicillin therapy.

International audience; In addition to five known compounds including three xanthones, tovophyllin A, rubraxanthone and garciniafuran, one pentacyclic triterpene, lupeol and one phytosterol, stigmasterol, a polyisoprenylated xanthone named allanxanthone B was isolated from the stem bark of Allanblackia monticola. The structure of the new compound was assigned as 2-geranyl-1,3,6-trihydroxy-2',2'-dimethyl[5',6':7,8]xanthone by means of spectroscopic analysis. The antimicrobial activities of some of these compounds against a range of micro-organisms are also reported.

International audience; Some odorant lactones are naturally present in fruits or in fermented products; they can also be used as food additives and can be produced by microorganisms at the industrial scale by biotechnological processes. Gamma-decalactone was previously shown to have antimicrobial properties. We determined by infrared spectroscopy measurements that this compound rapidly diffused into model phospholipid bilayers (within 2 min), modifying the general physical state of a dimyristoyl-L-alpha-phosphatidylcholine (DMPC) film. In vivo, the lactone strongly increased membrane fluidity in the model yeast Yarrowia lipolytica, as evaluated by fluorescence anisotropy measurements. This effect was more important than that of benzyl alcohol, which is known as a fluidizing agent in living cells, and may explain the toxic action of gamma-decalactone in microorganisms.

International audience; OBJECTIVES Video-thoracoscopic surgery (VTS) has been accepted as a safe and credible technique since 1990. Lung injury is one of the main perioperative complications. Few data are available about cardiac trauma and VTS-related false aneurysm of the left ventricular (LV) wall has not yet been reported. METHODS A 62-year old woman presented with a left thoracic empyema. Video-thoracoscopy was attempted for bacterial sampling and surgical drain of the pleura. A rapid conversion to open thoracotomy was necessary to control massive bleeding after the first thoracic port intrusion. An apical systolic murmur was found 2 weeks later during a systematic clinical examination. The patient was asymptomatic and had no personal history of cardiac disease. RESULTS Colour Doppler imaging showed two spurious aneurysms on the LV wall without any haemopericardium. Pericardial enhancement around the left ventricle was observed on the chest computerized tomography scan with the injection of contrast. After the careful excision of the two false aneurysms, a surgical repair was strengthened with a suture under a cardiopulmonary bypass. The postoperative course was uneventful and the patient was safe at 3 years. CONCLUSIONS This is the first report of LV traumatic false aneurysms secondary to an attempt of a video-thoracoscopic procedure. This is a rare but life-threatening complication because of the risk of spontaneous rupture. Left persistent thoracic empyemas associated with the ipsilateral mediastinum deviation carry a high risk of myocardial damage related to the trocar port intrusion.

Bacterial peptide deformylase (PDF) belongs to a sub-family of metalloproteases that catalyse the removal of the N-terminal formyl group from newly synthesised proteins. PDF is essential in prokaryotes and conserved throughout the eubacteria. It is therefore considered an attractive target for developing new antibacterial agents. Here, we report the crystal structures of four bacterial deformylases, free or bound to the naturally occurring antibiotic actinonin, including two from the major bacterial pathogens Pseudomonas aeruginosa and Staphylococcus aureus. The overall tertiary structure is essentially conserved but shows significant differences, namely at the C terminus, which are directly related to the deformylase type (i.e. I or II) they belong to. The geometry around the catalytic metal ion exhibits a high level of similarity within the different enzymes, as does the binding mode of actinonin to the various deformylases. However, some significant structural differences are found in the vicinity of the active site, highlighting the structural and molecular requirements for the design of a deformylase inhibitor active against a broad spectrum of bacterial strains.

Clinical practice guidelines (CPGs) are documents giving recommendations based on expert reasoning, weighing up the pros and cons of treatments on the basis of the available evidence. We propose a new approach to the construction of clinical decision support systems (CDSS), making use of the evidence-based medical reasoning used by experts in CPGs. In this study, we determined whether this approach could retrieve the recommendations for antibiotic prescription for empirical treatment in primary care.We manually extracted, from CPGs, all the properties of antibiotics underlying recommendations for their prescription or non-prescription. We then used these properties to establish an algorithm in the form of a sequence of conditions, leading to a list of recommended antibiotics. The optimal sequence was determined by studying, for each sequence, the degree of similarity between the list of antibiotics recommended in CPGs and the list obtained with the algorithm.12 antibiotic properties were used in the form of conditions in an algorithm. For 95% of clinical situations, 10 sequences retrieved the recommended treatment.This algorithm could be used in a CDSS for antibiotic treatment and would be useful for experts drawing up CPGs.

The Red recombinase system of bacteriophage Lambda has been used to inactivate chromosomal genes in bacteria using PCR products. In this study, we describe the replacement of the ampicillin resistance marker of helper plasmids pKD46 and pCP20 by a gentamicin resistance gene to disrupt chromosomal genes and then to eliminate FRT flanked resistance gene in multiple antibiotic-resistant Salmonella enterica strains.

International audience; In recent years, quantitative real-time PCR tests have been extensively developed in clinical microbiology laboratories for routine diagnosis of infectious diseases, particularly bacterial diseases. This molecular tool is well-suited for the rapid detection of bacteria directly in clinical specimens, allowing early, sensitive and specific laboratory confirmation of related diseases. It is particularly suitable for the diagnosis of infections caused by fastidious growth species, and the number of these pathogens has increased recently. This method also allows a rapid assessment of the presence of antibiotic resistance genes or gene mutations. Although this genetic approach is not always predictive of phenotypic resistances, in specific situations it may help to optimize the therapeutic management of patients. Finally, an approach combining the detection of pathogens, their mechanisms of antibiotic resistance, their virulence factors and bacterial load in clinical samples could lead to profound changes in the care of these infected patients.

International audience; OBJECTIVES: To evaluate the feasibility of a point prevalence survey for monitoring antibiotic use in a voluntary sample of French hospitals. METHODS: Demographic and medical data were collected for all inpatients. Additional characteristics regarding antimicrobial treatment, type of infection and microbiological results were collected only for patients receiving antimicrobials. RESULTS: Among 3964 patients in 38 hospitals, 343 (8.7%) received antimicrobial prophylaxis and 1276 (32.2%) antimicrobial therapy. The duration of surgical antimicrobial prophylaxis was >1 day in 41 out of 200 (21%) of the cases. Among patients with antimicrobial therapy, 959 (75.2%) received β-lactams (including 34.8% penicillins with β-lactam inhibitors, 22.1% third-generation cephalosporins and 7.8% carbapenems) and 301 (23.6%) received fluoroquinolones (50% orally). A total of 518 (40.6%) patients were treated with more than one drug and 345 (27.2%) were treated for >7 days. Patients treated for hospital-acquired infections (39.2%) were more likely to receive combinations (47.6% versus 34.4%, P < 0.01), carbapenems (14.4% versus 2.6%, P < 0.01), glycopeptides (14.4% versus 3.7%, P < 0.01) and antifungals (17% versus 5.3%, P < 0.01) for a longer duration (7.8 versus 6 days, P < 0.01). Fifty-six patients (4.4%) were treated for >7 days and did not have any microbiological sample drawn. The time allocated for the survey represented 18.3-25.0 h for 100 patients. CONCLUSIONS: The data provide directions for further interventions, such as better use of diagnostic tools, decreasing the treatment duration and the use of combinations. In addition, the survey shows that, although cumbersome, it is feasible to improve the representativeness of national data in European surveys.

Background In many Asian countries, Klebsiella pneumoniae (KP) is the second pathogen responsible for community-acquired pneumonia. Yet, very little is known about KP etiology in ALRI in Cambodia, a country that has one of the weakest medical infrastructures in the region. We present here the first clinico-radiological description of KP community-acquired ALRI in hospitalized Cambodian patients. Methods Through ALRI surveillance in two provincial hospitals, KP was isolated from sputum and blood cultures, and identified by API20E gallery from patients ≥ 5 years-old with fever and respiratory symptoms onset ≤14 days. Antibiotics susceptibility testing was provided systematically to clinicians when bacteria were isolated. We collected patients' clinical, radiological and microbiological data and their outcome 3 months after discharge. We also compared KP-related with other bacteria-related ALRI to determine risk factors for KP infection. Results From April 2007 to December 2009, 2315 ALRI patients ≥ 5 years-old were enrolled including 587 whose bacterial etiology could be assigned. Of these, 47 (8.0%) had KP infection; their median age was 55 years and 68.1% were females. Reported prior medication was high (42.5%). Patients' chest radiographs showed pneumonia (61.3% including 39% that were necrotizing), preexisting parenchyma lesions (29.5%) and pleural effusions alone (4.5%) and normal parenchyma (4.5%). Five patients had severe conditions on admission and one patient died during hospitalization. Of the 39 patients that were hospital discharged, 14 died including 12 within 1 month after discharge. Only 13 patients (28%) received an appropriate antibiotherapy. Extended-spectrum beta-lactamases (ESBL) - producing strains were found in 8 (17.0%) patients. Female gender (Odds ratio (OR) 2.1; p = 0.04) and diabetes mellitus (OR 3.1; p = 0.03) were independent risk factors for KP-related ALRI. Conclusions KP ALRI in Cambodia has high fatality rate, are more frequently found in women, and should be considered in diabetic patients. The extremely high frequency of ESBL-producing strains in the study is alarming in the context of uncontrolled antibiotic consumption and in absence of microbiology capacity in most public-sector hospitals.

International audience; The aim of the present retrospective observational clinical study was to assess the interindividual pharmacokinetic variability of plasma concentrations of amoxicillin or cloxacillin administered in high doses intravenously in critically ill patients, related to renal function or administration method.Four hundred and two plasma concentrations were measured at steady-state with a high performance liquid chromatography technique in 162 patients treated with 100 - 300 mg/kg/day of intravenous amoxicillin or cloxacillin.For both drugs and administration methods, plasma concentrations were significantly higher for patients with creatinine clearance below 60 ml/min, even though doses were adapted for renal impairment. the correlations calculated between plasma concentrations and creatinine level, creatinine clearance or doses were all low. There were fewer outlying drug concentrations in patients receiving continuous rather than intermittent regimens.Our results are in favor of adapting dosages of these beta-lactam antibiotics based on plasma concentrations, especially in cases of renal impairment.

Comment in Bacterial infection and MALT lymphoma. [N Engl J Med. 2004] Immunoproliferative small intestinal disease associated with Campylobacter jejuni. [N Engl J Med. 2004] Another immunoproliferative gastrointestinal condition responsive to antibiotics. [Rev Gastroenterol Disord. 2005]; International audience; BACKGROUND:Immunoproliferative small intestinal disease (also known as alpha chain disease) is a form of lymphoma that arises in small intestinal mucosa-associated lymphoid tissue (MALT) and is associated with the expression of a monotypic truncated immunoglobulin alpha heavy chain without an associated light chain. Early-stage disease responds to antibiotics, suggesting a bacterial origin. We attempted to identify a causative agent.METHODS:We performed polymerase chain reaction (PCR), DNA sequencing, fluorescence in situ hybridization, and immunohistochemical studies on intestinal-biopsy specimens from a series of patients with immunoproliferative small intestinal disease.RESULTS:Analysis of frozen intestinal tissue obtained from an index patient with immunoproliferative small intestinal disease who had a dramatic response to antibiotics revealed the presence of Campylobacter jejuni. A follow-up retrospective analysis of archival intestinal-biopsy specimens disclosed campylobacter species in four of six additional patients with immunoproliferative small intestinal disease.CONCLUSIONS:These results indicate that campylobacter and immunoproliferative small intestinal disease are associated and that C. jejuni should be added to the growing list of human pathogens responsible for immunoproliferative states.