Resistance of Pseudomonas aeruginosa and Staphylococcus aureus to the airway epithelium oxidative response assessed by a cell-free in vitro assay.

The antibacterial oxidative response, which relies on the production of hydrogen peroxide (H2O2) and hypothiocyanite (OSCN-), is a major line of defense protecting the human airway epithelium (HAE) from lesions when infected. The in vitro studies of the oxidative responses are performed mainly by one-shot H2O2 exposure that does not recapitulate the complex H2O2/LPO/SCN- system releasing the reactive oxygen species in airway secretions. A cell-free in vitro assay mimicking this system has been described but was not fully characterized. Here, we comprehensively characterized the hourly H2O2/OSCN- concentrations produced within this in vitro assay and assessed the resistance of Pseudomonas aeruginosa and Staphylococcus aureus clinical strains to the HAE oxidative response. We found that H2O2/OSCN- were steadily produced from 7h and up to 25h, but OSCN- was detoxified in 15 minutes by bacteria upon exposure. Preliminary tests on PA14 showed survival rates at 1-hour post-exposure (hpe) to H2O2 of roughly 50% for 105 and 107 colony-forming unit (CFU)/mL inocula, while 102 and 104 CFU/mL inocula were cleared after one hpe. Thirteen clinical strains were then exposed, highlighting that conversely to P. aeruginosa, S. aureus showed resistance to oxidative stress independently of its antibiotic resistance phenotype. Our results demonstrated how this in vitro assay can be helpful in assessing whether pathogens can resist the antibacterial oxidative HAE response. We anticipate these findings as a starting point for more sophisticated in vitro models that could serve as high-throughput screening for molecules targeting the bacterial antioxidant response.

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.

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).

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 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.

In vitro susceptibility of nonfermenting Gram-negative rods to meropenem-vaborbactam and delafloxacin.

Aim: Meropenem-vaborbactam and delafloxacin activities were not assessed against Achromobacter spp. (Achr), Burkholderia cepacia complex (Bcc) and Stenotrophomonas maltophilia (Smal). Methodology: A total of 106 Achr, 57 Bcc and 100 Smal were tested with gradient diffusion test of meropenem-vaborbactam, delafloxacin and comparators. Results: Meropenem-vaborbactam MIC50 were 4 µg/ml for Achr, 1 µg/ml for B. cepacia, 2 µg/ml for B. cenocepacia and B. multivorans, and 32 µg/ml for Smal. Delafloxacin MIC50 were 4 µg/ml for Achr, 0.25 µg/ml for B. cepacia and B. multivorans, 2 µg/ml for B. cenocepacia, and 0.5 µg/m for Smal. meropenem-vaborbactam MICs were fourfold lower than meropenem for 28.3% Achr, 77.2% B. cepacia, 53.8% B. cenocepacia and 77.2% B. multivorans. Conclusion: Meropenem-vaborbactam and delafloxacin are in vitro active against Bcc and Achr.

We assess the efficacy of two new antibiotics, meropenem­vaborbactam and delafloxacin, to kill rarely encountered bacteria. These bacteria, Achromobacter, Burkholderia and Stenotrophomonas maltophilia, mainly cause respiratory tract infections. Both antibiotics are found active against Achromobacter and Burkholderia, but not S. maltophilia.

Evaluation of ceftolozane-tazobactam susceptibility on a French nationwide collection of Enterobacterales.

OBJECTIVES: Ceftolozane-tazobactam (C/T) proved its efficacy for the treatment of infections caused by non-carbapenemase producing Pseudomonas aeruginosa and Enterobacterales. Here, we aimed to provide susceptibility data on a large series of Enterobacterales since the revision of EUCAST categorization breakpoints in 2020. METHODS: First, C/T susceptibility was determined on characterized Enterobacterales resistant to third generation cephalosporins (3GCs) (extended spectrum ß-lactamase [ESBL] production or different levels of AmpC overexpression) (n = 213) and carbapenem-resistant Enterobacterales (CRE) (n = 259), including 170 carbapenemase producers (CPE). Then, 1632 consecutive clinical Enterobacterales responsible for infection were prospectively collected in 23 French hospitals. C/T susceptibility was determined by E-test® (biomérieux) and broth microdilution (BMD) (Sensititre™, Thermo Scientific) to perform method comparison. RESULTS: Within the collection isolates, 88% of 3GC resistant strains were susceptible to C/T, with important variation depending on the resistance mechanism: 93% vs. 13% susceptibility for CTX-M and SHV-ESBL producers, respectively. Only 20% of the CRE were susceptible to C/T. Among CPE, 80% of OXA-48-like producers were susceptible to C/T, whereas all metallo-ß-lactamase producers were resistant. The prospective study revealed that 95.6% of clinical isolates were susceptible to C/T. Method comparison performed on these 1632 clinical isolates demonstrated 99% of categorization agreement between MIC to C/T determined by E-test® in comparison with the BMD (reference) and only 74% of essential agreement. CONCLUSION: Overall, C/T showed good activity against wild-type Enterobacterales, AmpC producers, and ESBL-producing Escherichia coli but is less active against ESBL-producing Klebsiella pneumoniae, and CRE. E-test® led to an underestimation of the MICs in comparison to the BMD reference.

A high-throughput sequencing approach identifies immunotherapeutic targets for bacterial meningitis in neonates.

BACKGROUND: Worldwide, Escherichia coli is the leading cause of neonatal Gram-negative bacterial meningitis, but full understanding of the pathogenesis of this disease is not yet achieved. Moreover, to date, no vaccine is available against bacterial neonatal meningitis. METHODS: Here, we used Transposon Sequencing of saturated banks of mutants (TnSeq) to evaluate E. coli K1 genetic fitness in murine neonatal meningitis. We identified E. coli K1 genes encoding for factors important for systemic dissemination and brain infection, and focused on products with a likely outer-membrane or extra-cellular localization, as these are potential vaccine candidates. We used in vitro and in vivo models to study the efficacy of active and passive immunization. RESULTS: We selected for further study the conserved surface polysaccharide Poly-ß-(1-6)-N-Acetyl Glucosamine (PNAG), as a strong candidate for vaccine development. We found that PNAG was a virulence factor in our animal model. We showed that both passive and active immunization successfully prevented and/or treated meningitis caused by E. coli K1 in neonatal mice. We found an excellent opsonophagocytic killing activity of the antibodies to PNAG and in vitro these antibodies were also able to decrease binding, invasion and crossing of E. coli K1 through two blood brain barrier cell lines. Finally, to reinforce the potential of PNAG as a vaccine candidate in bacterial neonatal meningitis, we demonstrated that Group B Streptococcus, the main cause of neonatal meningitis in developed countries, also produced PNAG and that antibodies to PNAG could protect in vitro and in vivo against this major neonatal pathogen. INTERPRETATION: Altogether, these results indicate the utility of a high-throughput DNA sequencing method to identify potential immunotherapy targets for a pathogen, including in this study a potential broad-spectrum target for prevention of neonatal bacterial infections. FUNDINGS: ANR Seq-N-Vaq, Charles Hood Foundation, Hearst Foundation, and Groupe Pasteur Mutualité.

An upgraded version of carbapenem inactivation method to detect Bacteroides fragilis carbapenemase.

An increase of carbapenemase-producing Bacteroides fragilis infections is observed. To detect such a resistance in B. fragilis, several tests exist that are expensive or show poor sensitivity and specificity. Therefore, we upgraded the Anaerobic Carbapenem Inactivation Method (Ana-CIM) to easily screen for carbapenemase-producing B. fragilis. The presence of carbapenemase cfiA gene was identified in 50 B. fragilis isolates by PCR. We modified the Ana-CIM by (1) increasing the bacterial inoculum, and (2) measuring the differences in diameter between the negative control and the testing disc. We correctly classified the cfiA-negative and positive isolates and could define a cut-off of positivity at 2 mm. Our modified Ana-CIM allowed to correctly discriminate the 31 cfiA-positive with meropenem MICs ranging from 1 to > 32 µg/mL. We anticipate that our modified Ana-CIM could be used in most clinical laboratories to easily screen for carbapenemase-producing B. fragilis, even at low levels.

The Nicotinic Receptor Polymorphism rs16969968 Is Associated with Airway Remodeling and Inflammatory Dysregulation in COPD Patients.

Genome-wide association studies unveiled the associations between the single nucleotide polymorphism rs16969968 of CHRNA5, encoding the nicotinic acetylcholine receptor alpha5 subunit (α5SNP), and nicotine addiction, cancer, and COPD independently. Here, we investigated α5SNP-induced epithelial remodeling and inflammatory response in human COPD airways. We included 26 α5SNP COPD patients and 18 wild-type α5 COPD patients in a multi-modal study. A comparative histologic analysis was performed on formalin-fixed paraffin-embedded lung tissues. Isolated airway epithelial cells from bronchial brushings were cultivated in the air-liquid interface. Broncho-alveolar fluids were collected to detect inflammatory mediators. Ciliogenesis was altered in α5SNP COPD bronchial and bronchiolar epithelia. Goblet cell hyperplasia was exacerbated in α5SNP small airways. The broncho-alveolar fluids of α5SNP COPD patients exhibited an increase in inflammatory mediators. The involvement of the rs16969968 polymorphism in airway epithelial remodeling and related inflammatory response in COPD prompts the development of innovative personalized diagnostic and therapeutic strategies.

Discrimination of Escherichia coli, Shigella flexneri, and Shigella sonnei using lipid profiling by MALDI-TOF mass spectrometry paired with machine learning.

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has become a staple in clinical microbiology laboratories. Protein-profiling of bacteria using this technique has accelerated the identification of pathogens in diagnostic workflows. Recently, lipid profiling has emerged as a way to complement bacterial identification where protein-based methods fail to provide accurate results. This study aimed to address the challenge of rapid discrimination between Escherichia coli and Shigella spp. using MALDI-TOF MS in the negative ion mode for lipid profiling coupled with machine learning. Both E. coli and Shigella species are closely related; they share high sequence homology, reported for 16S rRNA gene sequence similarities between E. coli and Shigella spp. exceeding 99%, and a similar protein expression pattern but are epidemiologically distinct. A bacterial collection of 45 E. coli, 48 Shigella flexneri, and 62 Shigella sonnei clinical isolates were submitted to lipid profiling in negative ion mode using the MALDI Biotyper Sirius® system after treatment with mild-acid hydrolysis (acetic acid 1% v/v for 15 min at 98°C). Spectra were then analyzed using our in-house machine learning algorithm and top-ranked features used for the discrimination of the bacterial species. Here, as a proof-of-concept, we showed that lipid profiling might have the potential to differentiate E. coli from Shigella species using the analysis of the top five ranked features obtained by MALDI-TOF MS in the negative ion mode of the MALDI Biotyper Sirius® system. Based on this new approach, MALDI-TOF MS analysis of lipids might help pave the way toward these goals.

A qnrD-Plasmid Promotes Biofilm Formation and Class 1 Integron Gene Cassette Rearrangements in Escherichia coli.

Bacteria within biofilms may be exposed to sub-minimum inhibitory concentrations (sub-MICs) of antibiotics. Cell-to-cell contact within biofilms facilitates horizontal gene transfers and favors induction of the SOS response. Altogether, it participates in the emergence of antibiotic resistance. Aminoglycosides at sub-MICs can induce the SOS response through NO accumulation in E. coli carrying the small plasmid with the quinolone resistance qnrD gene (pDIJ09-518a). In this study, we show that in E. coli pDIJ09-518a, the SOS response triggered by sub-MICs of aminoglycosides has important consequences, promoting genetic rearrangement in class 1 integrons and biofilm formation. We found that the integrase expression was increased in E. coli carrying pDIJ09-518a in the presence of tobramycin, which was not observed for the WT isogenic strain that did not carry the qnrD-plasmid. Moreover, we showed that biofilm production was significantly increased in E. coli WT/pDIJ09-518a compared to the WT strain. However, such a higher production was decreased when the Hmp-NO detoxification pathway was fully functional by overexpressing Hmp. Our results showing that a qnrD-plasmid can promote biofilm formation in E. coli and potentiate the acquisition and spread of resistance determinants for other antibiotics complicate the attempts to counteract antibiotic resistance and prevention of biofilm development even further. We anticipate that our findings emphasize the complex challenges that will impact the decisions about antibiotic stewardship, and other decisions related to retaining antibiotics as effective drugs and the development of new drugs.

First use of a new rapid multiplex PCR system for the microbiological diagnosis and the clinical management of severe infectious keratitis: A case report.

Purpose: We report the use of a rapid multiplex polymerase chain reaction (PCR) system in the microbiological diagnosis and the therapeutic management of a severe bacterial keratitis case. Observations: During the management of a severe bacterial keratitis case, standard microbiological diagnostic methods were performed. At the same time, an additional ocular swab sampling from the cornea was performed and analyzed using two rapid multiplex PCR assays allowing the simultaneous detection of 29 different virus, yeast and bacteria genomes. Using combination of two rapid multiplex PCR systems, the microbiological diagnosis of a severe Pseudomonas aeruginosa induced keratitis was performed within 90 minutes after an ocular sampling. A rapid subsequent adaptation of local antibiotic treatment was performed allowing to the young patient to regain 6 months after her hospital admission a final visual acuity of 20/20 in her right eye. Conclusions and importance: The present case report suggests that the use of a rapid multiplex PCR strategy may result in a decrease of the mean hospital stage duration for severe infectious keratitis and in an improvement of the clinical outcome of severe keratitis infections. Nevertheless, additional prospective studies are needed to evaluate whether this innovative strategy may replace the current standard approach and optimize the therapeutic management of severe corneal infections.

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.

Antimicrobial Resistance in Enterobacterales Recovered from Urinary Tract Infections in France.

In the context of increasing antimicrobial resistance in Enterobacterales, the management of these UTIs has become challenging. We retrospectively assess the prevalence of antimicrobial resistance in Enterobacterales isolates recovered from urinary tract samples in France, between 1 September 2017, to 31 August 2018. Twenty-six French clinical laboratories provided the susceptibility of 134,162 Enterobacterales isolates to 17 antimicrobials. The most frequent species were E. coli (72.0%), Klebsiella pneumoniae (9.7%), Proteus mirabilis (5.8%), and Enterobacter cloacae complex (2.9%). The overall rate of ESBL-producing Enterobacterales was 6.7%, and ranged from 1.0% in P. mirabilis to 19.5% in K. pneumoniae, and from 3.1% in outpatients to 13.6% in long-term care facilities. Overall, 4.1%, 9.3% and 10.5% of the isolates were resistant to cefoxitin, temocillin and pivmecillinam. Cotrimoxazole was the less active compound with 23.4% resistance. Conversely, 4.4%, 12.9%, and 14.3% of the strains were resistant to fosfomycin, nitrofurantoin, and ciprofloxacin. However, less than 1% of E. coli was resistant to fosfomycin and nitrofurantoin. We identified several trends in antibiotics resistances among Enterobacterales isolates recovered from the urinary tract samples in France. Carbapenem-sparing drugs, such as temocillin, mecillinam, fosfomycin, cefoxitin, and nitrofurantoin, remained highly active, including towards ESBL-E.

A qnr-plasmid allows aminoglycosides to induce SOS in Escherichia coli.

The plasmid-mediated quinolone resistance (PMQR) genes have been shown to promote high-level bacterial resistance to fluoroquinolone antibiotics, potentially leading to clinical treatment failures. In Escherichia coli, sub-minimum inhibitory concentrations (sub-MICs) of the widely used fluoroquinolones are known to induce the SOS response. Interestingly, the expression of several PMQR qnr genes is controlled by the SOS master regulator, LexA. During the characterization of a small qnrD-plasmid carried in E. coli, we observed that the aminoglycosides become able to induce the SOS response in this species, thus leading to the elevated transcription of qnrD. Our findings show that the induction of the SOS response is due to nitric oxide (NO) accumulation in the presence of sub-MIC of aminoglycosides. We demonstrated that the NO accumulation is driven by two plasmid genes, ORF3 and ORF4, whose products act at two levels. ORF3 encodes a putative flavin adenine dinucleotide (FAD)-binding oxidoreductase which helps NO synthesis, while ORF4 codes for a putative fumarate and nitrate reductase (FNR)-type transcription factor, related to an O2-responsive regulator of hmp expression, able to repress the Hmp-mediated NO detoxification pathway of E. coli. Thus, this discovery, that other major classes of antibiotics may induce the SOS response could have worthwhile implications for antibiotic stewardship efforts in preventing the emergence of resistance.

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.