Current concepts on Pseudomonas aeruginosa interaction with human airway epithelium.

Pseudomonas aeruginosa is a major, but opportunistic, respiratory pathogen, which rarely infects healthy individuals, mainly due to the barrier effect of the human airway epithelium (HAE). This review explores the interaction of P. aeruginosa with HAE and the progression of the infection. The basolateral part of the epithelium, which includes the basolateral membrane of the epithelial cells and the basement membrane, is inaccessible in normal tight epithelia with intact junctions. We highlight how P. aeruginosa exploits weaknesses in the HAE barrier to gain access to the basolateral part of the epithelium. This access is crucial to initiate respiratory infection and is mainly observed in the injured epithelium, in repairing or chronically remodeled epithelium, and during extrusion of senescent cells or cell multiplication during normal epithelium renewal. The subsequent adhesion of the bacteria and cytotoxic action of virulence factors, including the toxins delivered by the type 3 secretion system (T3SS), lead to retractions and cell death. Eventually, P. aeruginosa progressively reaches the basement membrane and propagates radially through the basal part of the epithelium to disseminate using twitching and flagellar motility.

Development of an antibody fused with an antimicrobial peptide targeting Pseudomonas aeruginosa: A new approach to prevent and treat bacterial infections.

The increase in emerging drug resistant Gram-negative bacterial infections is a global concern. In addition, there is growing recognition that compromising the microbiota through the use of broad-spectrum antibiotics can impact long term patient outcomes. Therefore, there is the need to develop new bactericidal strategies to combat Gram-negative infections that would address these specific issues. In this study, we report and characterize one such approach, an antibody-drug conjugate (ADC) that combines (i) targeting the surface of a specific pathogenic organism through a monoclonal antibody with (ii) the high killing activity of an antimicrobial peptide. We focused on a major pathogenic Gram-negative bacterium associated with antibacterial resistance: Pseudomonas aeruginosa. To target this organism, we designed an ADC by fusing an antimicrobial peptide to the C-terminal end of the VH and/or VL-chain of a monoclonal antibody, VSX, that targets the core of P. aeruginosa lipopolysaccharide. This ADC demonstrates appropriately minimal levels of toxicity against mammalian cells, rapidly kills P. aeruginosa strains, and protects mice from P. aeruginosa lung infection when administered therapeutically. Furthermore, we found that the ADC was synergistic with several classes of antibiotics. This approach described in this study might result in a broadly useful strategy for targeting specific pathogenic microorganisms without further augmenting antibiotic resistance.

Current cough and sputum assessed by the cough and sputum assessment-questionnaire (CASA-Q) is associated with quality of life impairment in cystic fibrosis.

BACKGROUND: Cough and sputum are major symptoms in cystic fibrosis (CF) that contribute to the impairment of quality of life. METHODS: This prospective single centre cross-sectional pilot study aimed to evaluate the results of a self-administered questionnaire assessing cough and sputum symptoms (2 domains), and their impact (2 domains) on daily activities in the previous week, named the Cough and Sputum Assessment Questionnaire (CASA-Q) in CF adult patients at stable state, and to analyse associations with clinical, functional, microbiological, radiological data, and two quality of life scales: the Cystic Fibrosis Questionnaire Revised (CFQ-R) and the Saint George Respiratory Questionnaire (SGRQ). RESULTS: Forty-eight patients were included in this analysis (69% men; median age of 27.8 ± 8.1 years; median body mass index of 21.8 + 3.3 kg/m²; mean FEV1 of 64 ± 30% of the predicted value). The mean values of the CASA-Q domains were 58 ± 23 for cough symptoms, 77 ± 24 for cough impact, 62 ± 25 for sputum symptoms and 84 ± 21 for sputum impact. Impairment in CASA-Q cough and sputum domains was associated with dyspnea mMRC scale (p < 0.005 for all 4 domains of CASA-Q) and exacerbations in the previous year (p < 0.05 for CASA-Q symptoms domains). We also found correlations between all domains of the CASA-Q and quality of life questionnaires including SGRQ (p < 0.001) and to a lesser extend CFQ-R. We identified a clinical phenotype (female gender, ΔF508 heterozygous mutation, dyspnea mMRC scale) associated with an impairment of CASA-Q score and quality of life using a 2-step cluster analysis. CONCLUSIONS: CASA-Q allows the assessment of cough and sputum in CF adult patients and is associated with quality of life impairment. This simple easy-to-use tool could be used in routine clinical practice and in clinical studies to assess cough and sputum in CF patients. TRIAL REGISTRATION: The study was registered on ClinicalTrials.gov (NCT02924818, first posted on 5th October 2016).

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

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

Capnocytophaga zoonotic infections: a 10-year retrospective study (the French CANCAN study).

Zoonotic species of Capnocytophaga genus belong to the oral microbiota of dogs and cats. They may be responsible for serious human infections, mainly after animal bites, with a high mortality rate. In France, only few cases have been reported and no multicenter study has been conducted. Our aim was to describe the French epidemiology of Capnocytophaga zoonosis. We conducted a multicenter (21 centers) retrospective non-interventional, observational study in France describing the epidemiology of Capnocytophaga zoonosis (C. canimorsus, C. cynodegmi, C. canis) over 10 years with regard to clinical and bacteriological data. From 2009 to 2018, 44 cases of Capnocytophaga zoonotic infections were described (C. canimorsus, n = 41; C. cynodegmi, n = 3). We observed an increase (2.5 times) in the number of cases over the study period (from the first to the last 5 years of the study). The most frequent clinical presentations were sepsis (n = 37), skin and soft tissue infections (n = 12), meningitis (n = 8), osteoarticular infections (n = 6), and endocarditis (n = 2). About one-third of patients with sepsis went into septic shock. Mortality rate was 11%. Mortality and meningitis rates were significantly higher for alcoholic patients (p = 0.044 and p = 0.006, respectively). Other comorbidities included smoking, splenectomy, diabetes mellitus, and immunosuppressive therapy are associated to zoonotic Capnocytophaga infection. Eighty-two percent of cases involved contact with dogs, mostly included bites (63%). Despite all isolates were susceptible to the amoxicillin-clavulanic acid combination, three of them were resistant to amoxicillin.

Contribution of the anaerobic blood culture vial for the recovery of Candida glabrata: A retrospective multicentric study.

Although Candida spp are aerobic microorganisms, some Candida strains, mainly Candida glabrata, can be recovered from anaerobic blood culture vials. We assessed the contribution of the anaerobic vials for the diagnosis of candidemia, especially for C. glabrata. We conducted a multicenter retrospective study including eight university or regional hospitals. A single episode of monomicrobial candidemia per patient was included from September 1st, 2016, to August 31st, 2019. The characteristics of all aerobic and anaerobic blood culture vials sampled within 2 h before and after the first positive blood culture vials were recorded (type of vials, result, and for positive vials time-to-positivity and Candida species). Overall, 509 episodes of candidemia were included. The main species were C. albicans (55.6%) followed by C. glabrata (17.1%), C. parapsilosis (4.9%), and C. tropicalis (4.5%). An anaerobic vial was positive in 76 (14.9%) of all episodes of which 56 (73.8%) were due to C. glabrata. The number of C. glabrata infections only positive in anaerobic vials was 1 (2.6%), 1 (11.1%), and 15 (37.5%) with the BACT/ALERT 3D the BACT/ALERT VIRTUO and the BACTEC FX instrument, respectively (P < 0.01). The initial positivity of an anaerobic vial was highly predictive of the isolation of C. glabrata with the BACTEC FX (sensitivity of 96.8%). C. glabrata time-to-positivity was shorter in anaerobic vial than aerobic vial with all instruments. Anaerobic blood culture vials improve the recovery of Candida spp mainly C. glabrata. This study could be completed by further analyses including mycological and pediatric vials. LAY SUMMARY: Although Candida spp are aerobic microorganisms, C. glabrata is able to grow in anaerobic conditions. In blood culture, the time-to-positivity of C. glabrata is shorter in anaerobic than aerobic vials. Only the anaerobic vial was positive in up to 15 (37.5%) C. glabrata bloodstream infections.

Insomnia in adults with cystic fibrosis: strong association with anxiety/depression and impaired quality of life.

BACKGROUND: While sleep disruption is a common complaint among children with cystic fibrosis (CF), only a few studies have investigated insomnia in adults. The aim of this study was to identify factors associated with insomnia in clinically stable adult CF patients. METHODS: Twenty-eight CF patients (18M/10F), with a median age of 27 (22-34) (median (interquartile range) years and a median of forced expiratory volume in one second of 72 (39-93) % predicted completed questionnaires on insomnia (Insomnia Severity Index, ISI), sleep quality (PSQI), daytime sleepiness (Epworth), restless legs syndrome (IRLS), pain (NRS), anxiety/depression (HAD) and quality of life (CFQ-R 14+). Respiratory assessment data, including symptoms, sputum analysis, arterial blood gases, 6-min walking test, pulmonary function tests and polysomnographic variables, were also analyzed. RESULTS: Forty-three percent of patients were insomniac (ISI > 7). Compared with non-insomniac patients (ISI ≤ 7), insomniac patients had more severely impaired quality of life and a higher HAD score: median anxiety score of 9 (8-11) vs 4 (3-6) (p < 0.0001), median depression score of 7 (5-10) vs 1 (1-4) (p < 0.001), with a positive correlation between ISI and HAD anxiety/depression scores (r = 0.702/r = 0.701, respectively, p < 0.0001). Insomnia was also associated with mMRC dyspnea scale ≥ 2, restless legs syndrome, pain and lower SpO2 during sleep. CONCLUSIONS: The strong association between insomnia, impaired quality of life and increased HAD score should prompt physicians to be particularly attentive to the management of anxiety and depression in adult CF patients with insomnia. TRIAL REGISTRATION: On clinicaltrials.gov (NCT02924818, date of registration: October 5, 2016).

Phenotypic and genotypic quinolone resistance in Escherichia coli underlining GyrA83/87 mutations as a target to detect ciprofloxacin resistance.

BACKGROUND: Quinolone resistance (QR) is one component of the MDR emerging in Escherichia coli and is of particular concern given the widespread use of fluoroquinolones. OBJECTIVES: To characterize the QR phenotypes and genotypes in E. coli responsible for bloodstream infections and to propose molecular determinants that could be targeted to predict ciprofloxacin resistance. METHODS: E. coli isolates from blood cultures in three French hospitals were studied for quinolone MICs and characterization of genotypic QR determinants (QRg). RESULTS: Among 507 isolates tested for MICs, 148 (29.2%) were resistant to quinolones based on EUCAST breakpoints and 143 (28.2%) harboured at least one QRg. QRg were mainly mutations in the QRDR (138 isolates, 27.2%), with 55.8% of these isolates carrying at least three QRDR mutations. gyrA mutations predominated (92.8%) followed by parC (61.6%), parE (32.6%) and gyrB (1.4%) mutations. Only 4.7% of the isolates harboured a plasmid-mediated quinolone resistance (PMQR) gene: aac(6')-Ib-cr (60.0%) or qnr (qnrS, qnrB) (32.0%). For the first time in France, we reported the qepA4 allele of the plasmid-encoded efflux pump QepA. Only five isolates carried PMQR without a QRDR mutation. The positive predictive value (PPV) for ciprofloxacin resistance was 100% for any QRg and 99.2% for gyrA mutations specifically. CONCLUSIONS: QR observed in E. coli isolates involved in bloodstream infections is still mainly due to QRDR mutations, especially at codons GyrA83/87, which could be used as a molecular target to rapidly detect resistance.

Antibiotic resistance and virulence: Understanding the link and its consequences for prophylaxis and therapy.

"Antibiotic resistance is usually associated with a fitness cost" is frequently accepted as common knowledge in the field of infectious diseases. However, with the advances in high-throughput DNA sequencing that allows for a comprehensive analysis of bacterial pathogenesis at the genome scale, including antibiotic resistance genes, it appears that this paradigm might not be as solid as previously thought. Recent studies indicate that antibiotic resistance is able to enhance bacterial fitness in vivo with a concomitant increase in virulence during infections. As a consequence, strategies to minimize antibiotic resistance turn out to be not as simple as initially believed. Indeed, decreased antibiotic use may not be sufficient to let susceptible strains outcompete the resistant ones. Here, we put in perspective these findings and review alternative approaches, such as preventive and therapeutic anti-bacterial immunotherapies that have the potential to by-pass the classic antibiotics.

Emergence of Antimicrobial-Resistant Escherichia coli of Animal Origin Spreading in Humans.

In the context of the great concern about the impact of human activities on the environment, we studied 403 commensal Escherichia coli/Escherichia clade strains isolated from several animal and human populations that have variable contacts to one another. Multilocus sequence typing (MLST) showed a decrease of diversity 1) in strains isolated from animals that had an increasing contact with humans and 2) in all strains that had increased antimicrobial resistance. A specific B1 phylogroup clonal complex (CC87, Institut Pasteur schema nomenclature) of animal origin was identified and characterized as being responsible for the increased antimicrobial resistance prevalence observed in strains from the environments with a high human-mediated antimicrobial pressure. CC87 strains have a high capacity of acquiring and disseminating resistance genes with specific metabolic and genetic determinants as demonstrated by high-throughput sequencing and phenotyping. They are good mouse gut colonizers but are not virulent. Our data confirm the predominant role of human activities in the emergence of antimicrobial resistance in the environmental bacterial strains and unveil a particular E. coli clonal complex of animal origin capable of spreading antimicrobial resistance to other members of microbial communities.

Factors associated with carriage of carbapenem-non-susceptible Enterobacteriaceaein North-Eastern France and outcomes of infected patients.

Background: Carbapenems are frequently used as a last resort to treat infections caused by multidrug-resistant Gram-negative organisms, thus carbapenem-non-susceptible Enterobacteriaceae (CNSE) is an emerging health threat. Objectives: To assess risk factors and outcomes of CNSE carriage. Patients and methods: We conducted a matched case-control study in six hospitals in North-Eastern France. The controls were patients harbouring carbapenem-susceptible Enterobacteriaceae. Fifty-five cases and 110 controls were included. Results: Most of the CNSE isolates were Enterobacter cloacae and Klebsiella pneumoniae . Carbapenemase production was observed in 40% of isolates and they produced OXA-48 only. CNSE carriage was significantly associated with recent antibiotic use ( P = 0.014), particularly carbapenems ( P = 0.03) and fluoroquinolones ( P = 0.016). A multivariate analysis using conditional logistic regression showed that the presence of concomitant infection(s) (OR: 9.83; 95% CI 3.04-21.39, P = 0.0031), nosocomial infections (OR: 7.84; 95% CI 2.00-12.54, P = 0.0063) and a high age (OR: 1.07; 95% CI 1.01-1.06, P = 0.038) were independently associated with CNSE carriage. Moreover, patients infected with CNSE had worse outcomes: fewer resolved infections at 1 month ( P = 0.02), and they had a higher mortality rate ( P = 0.0004) and longer hospital stays ( P = 0.02). Conclusions: We identified three independent risk factors for CNSE carriage as well as worse outcomes in infected patients in North-Eastern France. This highlights the importance of early detection of CNSE and the need for antimicrobial therapy re-evaluation after bacteriological analysis has been performed.

qnrA6 genetic environment and quinolone resistance conferred on Proteus mirabilis.

OBJECTIVES: To determine the genetic location and environment of the qnrA6 gene in Proteus mirabilis PS16 where it was first described and to characterize the quinolone resistance qnrA6 confers. METHODS: Transformation experiments and Southern blotting were performed for plasmid and genomic DNA of P. mirabilis PS16 to determine the qnrA6 location. Combinatorial PCRs with primers in qnrA6 and genes usually surrounding qnrA genes were used to determine the genetic environment. The qnrA6 coding region, including or not the promoter region, was cloned into vectors pTOPO and pBR322 and the MICs of six quinolones were measured for transformants of Escherichia coli TOP10 and P. mirabilis ATCC 29906 Rif(R). RESULTS: qnrA6 was shown to be chromosomally encoded in P. mirabilis PS16 and its genetic environment was 81%-87% similar to that of qnrA2 in the Shewanella algae chromosome. The 5138 bp region up- and downstream of qnrA6 contained an IS10 sequence surrounded by two ISCR1. This resulted in qnrA6 being displaced 1.9 kb from its native promoter but supplied a promoter present in ISCR1. qnrA6 cloned into pTOPO and pBR322 conferred a 4-32-fold increase in fluoroquinolone MICs when expressed in E. coli but only 2-3-fold in P. mirabilis. When including the promoter region, a further increase in resistance was observed in both species, reaching MIC values above clinical breakpoints for only P. mirabilis. CONCLUSIONS: qnrA6 is the first chromosomally located qnrA gene described in Enterobacteriaceae. The quinolone resistance conferred by qnrA6 depends on the proximity of an efficient promoter and the host strain where it is expressed.

Extended-spectrum antibodies protective against carbapenemase-producing Enterobacteriaceae.

BACKGROUND: Carbapenem-resistant Enterobacteriaceae (CRE) are responsible for worldwide outbreaks and antibiotic treatments are problematic. The polysaccharide poly-(ß-1,6)-N-acetyl glucosamine (PNAG) is a vaccine target detected on the surface of numerous pathogenic bacteria, including Escherichia coli. Genes encoding PNAG biosynthetic proteins have been identified in two other main pathogenic Enterobacteriaceae, Enterobacter cloacae and Klebsiella pneumoniae. We hypothesized that antibodies to PNAG might be a new therapeutic option for the different pan-resistant pathogenic species of CRE. METHODS: PNAG production was detected by confocal microscopy and its role in the formation of the biofilm (for E. cloacae) and as a virulence factor (for K. pneumoniae) was analysed. The in vitro (opsonophagocytosis killing assay) and in vivo (mouse models of peritonitis) activity of antibodies to PNAG were studied using antibiotic-susceptible and -resistant E. coli, E. cloacae and K. pneumoniae. A PNAG-producing strain of Pseudomonas aeruginosa, an organism that does not naturally produce this antigen, was constructed by adding the pga locus to a strain with inactive alg genes responsible for the production of P. aeruginosa alginate. Antibodies to PNAG were tested in vitro and in vivo as above. RESULTS: PNAG is a major component of the E. cloacae biofilm and a virulence factor for K. pneumoniae. Antibodies to PNAG mediated in vitro killing (>50%) and significantly protected mice against the New Delhi metallo-ß-lactamase-producing E. coli (P = 0.02), E. cloacae (P = 0.0196) and K. pneumoniae (P = 0.006), against K. pneumoniae carbapenemase (KPC)-producing K. pneumoniae (P = 0.02) and against PNAG-producing P. aeruginosa (P = 0.0013). Thus, regardless of the Gram-negative bacterial species, PNAG expression is the sole determinant of the protective efficacy of antibodies to this antigen. CONCLUSIONS: Our findings suggest antibodies to PNAG may provide extended-spectrum antibacterial protective activity.

Extended spectrum ß-lactamase and plasmid mediated quinolone resistance in Escherichia coli fecal isolates from healthy companion animals in Algeria.

The aim of this study was to evaluate the rate of fecal carriage of Escherichia coli strains producing Extended-spectrum ß-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR) isolated from healthy pets (dogs and cats) in Algeria. Fecal samples from 171 healthy pets (102 dogs and 69 cats) in one veterinary practice and private owners were included. After isolates identification, antibiotic susceptibility was determined by disk diffusion procedure. ESBL were detected by combination disk tests. PCR and sequencing were used to characterize genes encoding ESBLs and PMQR. Transfer of ESBL and PMQR genes was assessed by conjugation experiments. Phylogenetic groups of E. coli were determined by PCR. Of the 171 animals, 20 carried an ESBL producing E. coli giving a prevalence of ESBL fecal carriage of 11.7%. All isolates were susceptible to carbapenems, cefoxitin, piperacillin-tazobactam, amikacin and fosfomycine. For the rest of the tested ß-lactams, susceptibility rates ranged from 35% to 70% for cefepime and amoxicillin-clavulanic acid respectively. Concerning the non-beta-lactams antibiotics, the rates of susceptibility ranged between 5% to trimethoprim and 95% for chloramphenicol. The beta-lactamase genes identified in E. coli isolates were blaCTX-M-15, blaCTX-M-1, blaSHV-12 and blaTEM-1. The PMQR determinants aac(6')-Ib-cr, qnrS1 and qnrB5 genes were identified in 15 isolates. Transconjugants were obtained for two isolates. Phylogenetic analysis showed that E. coli isolates belong to commensal phylogroups of A and B1. We reported here for the first time in Algeria ESBL and PMQR-producing E. coli in healthy cats and dogs.

Enhanced in vivo fitness of carbapenem-resistant oprD mutants of Pseudomonas aeruginosa revealed through high-throughput sequencing.

An important question regarding the biologic implications of antibiotic-resistant microbes is how resistance impacts the organism's overall fitness and virulence. Currently it is generally thought that antibiotic resistance carries a fitness cost and reduces virulence. For the human pathogen Pseudomonas aeruginosa, treatment with carbapenem antibiotics is a mainstay of therapy that can lead to the emergence of resistance, often through the loss of the carbapenem entry channel OprD. Transposon insertion-site sequencing was used to analyze the fitness of 300,000 mutants of P. aeruginosa strain PA14 in a mouse model for gut colonization and systemic dissemination after induction of neutropenia. Transposon insertions in the oprD gene led not only to carbapenem resistance but also to a dramatic increase in mucosal colonization and dissemination to the spleen. These findings were confirmed in vivo with different oprD mutants of PA14 as well as with related pairs of carbapenem-susceptible and -resistant clinical isolates. Compared with OprD(+) strains, those lacking OprD were more resistant to killing by acidic pH or normal human serum and had increased cytotoxicity against murine macrophages. RNA-sequencing analysis revealed that an oprD mutant showed dramatic changes in the transcription of genes that may contribute to the various phenotypic changes observed. The association between carbapenem resistance and enhanced survival of P. aeruginosa in infected murine hosts suggests that either drug resistance or host colonization can cause the emergence of more pathogenic, drug-resistant P. aeruginosa clones in a single genetic event.

Lung concentrations of ceftazidime administered by continuous versus intermittent infusion in patients with ventilator-associated pneumonia.

Ceftazidime is a beta-lactam compound that exerts a time-dependent bactericidal effect. Numerous arguments are in favor of continuous administration of ceftazidime, both for reasons of clinical efficacy and to preserve bacteriological mutation. We report a prospective, single-center, parallel-group, randomized, controlled trial comparing two modes of administration of ceftazidime, namely, continuous administration (loading dose of 20 mg/kg of body weight followed by 60 mg/kg/day) versus intermittent administration (20 mg/kg over 30 min every 8 h) in 34 patients with ventilator-associated pneumonia due to Gram-negative bacilli. The study was performed over 48 h with 13 and 18 assessments of serum ceftazidime in the continuous-infusion group (group A) and the intermittent-fusion group (group B), respectively. Bronchoalveolar lavage (BAL) was performed at steady state in both groups at 44 h to determine ceftazidime levels in the epithelial lining fluid. We chose a predefined threshold of 20 mg/liter for serum concentrations of ceftazidime because of ecological conditions in our center. The median time above 20 mg/liter (T>20 mg) was 100% in group A versus 46% in group B. In group A, 14/17 patients had 100% T>20 mg, versus only 1/17 patients in group B. In the epithelial lining fluid, the median concentration of ceftazidime was 12 mg/liter in group A versus 6 mg/liter in group B. A threshold of 8 mg/liter in the epithelial lining fluid was achieved twice as often in group A as in group B. This study of ceftazidime concentrations in the epithelial lining fluid indicates that continuous infusion presents advantages in terms of pharmacodynamics and predictable efficacy in patients presenting ventilator-associated pneumonia.

Discrimination between native and Tn6010-associated oqxAB in Klebsiella spp., Raoultella spp., and other Enterobacteriaceae by using a two-step strategy.

We developed a two-step PCR-based strategy to detect genes encoding OqxAB, allowing a specific assignment of Tn6010-associated oqxAB in Enterobacteriaceae. Chromosomal location in this setup was confirmed by hybridization with I-CeuI-restricted genomes. This approach led us to find that Klebsiella sp. and Raoultella sp. reference strains chromosomally carried oqxAB.

High Blood Eosinophil Count at Stable State is Not Associated with Airway Microbiota Distinct Profile in COPD.

Purpose: The heterogeneity of clinical features in COPD at stable state has been associated with airway microbiota. Blood eosinophil count (BEC) represents a biomarker for a pejorative evolution of COPD, including exacerbations and accelerated FEV1 decline. We aimed to analyse the associations between BEC and airway microbiota in COPD at stable state. Patients and Methods: Adult COPD patients at stable state (RINNOPARI cohort) were included and characterised for clinical, functional, biological and morphological features. BEC at inclusion defined 2 groups of patients with low BEC <300/mm3 and high BEC ≥300/mm3. Sputa were collected and an extended microbiological culture was performed for the identification of viable airway microbiota. Results: Fifty-nine subjects were included. When compared with the low BEC (n=40, 67.8%), the high BEC group (n=19, 32.2%) had more frequent exacerbations (p<0.001) and more pronounced cough and sputum (p<0.05). The global composition, the number of bacteria per sample and the α-diversity of the microbiota did not differ between groups, as well as the predominant phyla (Firmicutes), or the gender repartition. Conclusion: In our study, high BEC in COPD at stable state was associated with a clinical phenotype including frequent exacerbation, but no distinct profile of viable airway microbiota compared with low BEC.

Bronchiectasis in renal transplant patients: a cross-sectional study.

BACKGROUND: Bronchiectasis is a chronic airway disease characterized by permanent and irreversible abnormal dilatation of bronchi. Several studies have reported the development of bronchiectasis after renal transplantation (RT), but no prospective study specifically assessed bronchiectasis in this population. This study aimed to compare features of patients with bronchiectasis associated with RT to those with idiopathic bronchiectasis. METHODS: Nineteen patients with bronchiectasis associated with RT (RT-B group) and 23 patients with idiopathic bronchiectasis (IB group) were prospectively included in this monocentric cross-sectional study. All patients underwent clinical, functional, laboratory, and CT scan assessments. Sputum was collected from 25 patients (n = 11 with RT-B and n = 14 with IB) and airway microbiota was analyzed using an extended microbiological culture. RESULTS: Dyspnea (≥ 2 on mMRC scale), number of exacerbations, pulmonary function tests, total bronchiectasis score, severity and prognosis scores (FACED and E-FACED), and quality of life scores (SGRQ and MOS SF-36) were similar in the RT-B and IB groups. By contrast, chronic cough was less frequent in the RT-B group than in the IB group (68% vs. 96%, p = 0.03). The prevalence and diversity of the airway microbiota in sputum were similar in the two groups. CONCLUSION: Clinical, functional, thoracic CT scan, and microbiological characteristics of bronchiectasis are overall similar in patients with IB and RT-B. These results highlight that in RT patients, chronic respiratory symptoms and/or airway infections should lead to consider the diagnosis of bronchiectasis. Further studies are required to better characterize the pathophysiology of RT-B including airway microbiota, its incidence, and impact on therapeutic management.