Gut colonisation with multidrug-resistant Klebsiella pneumoniae worsens Pseudomonas aeruginosa lung infection.

Carbapenemase-producing Enterobacterales (CPE) are spreading rapidly in hospital settings. Asymptomatic CPE gut colonisation may be associated with dysbiosis and gut-lung axis alterations, which could impact lung infection outcomes. In this study, in male C57BL/6JRj mice colonised by CPE, we characterise the resulting gut dysbiosis, and analyse the lung immune responses and outcomes of subsequent Pseudomonas aeruginosa lung infection. Asymptomatic gut colonisation by CPE leads to a specific gut dysbiosis and increases the severity of P. aeruginosa lung infection through lower numbers of alveolar macrophages and conventional dendritic cells. CPE-associated dysbiosis is characterised by a near disappearance of the Muribaculaceae family and lower levels of short-chain fatty acids. Faecal microbiota transplantation restores immune responses and outcomes of lung infection outcomes, demonstrating the involvement of CPE colonisation-induced gut dysbiosis in altering the immune gut-lung axis, possibly mediated by microbial metabolites such as short-chain fatty acids.

Progressive in vivo development of resistance to cefiderocol in Pseudomonas aeruginosa.

We report in vivo development of cefiderocol (FDC) resistance among four sequential Pseudomonas aeruginosa clinical isolates ST244 recovered from a single patient, without exposure to FDC, which raises concern about the effectiveness of this novel drug. The first recovered P. aeruginosa isolate (P-01) was susceptible to FDC (2 µg/mL), albeit this MIC value was higher than that of a wild-type P. aeruginosa (0.12-0.25 µg/ml). The subsequent isolated strains (P-02, P-03, P-04) displayed increasing levels of FDC MICs (8, 16, and 64 µg/ml, respectively). Those isolates also showed variable and gradual increasing levels of resistance to most ß-lactams tested in this study. Surprisingly, no acquired ß-lactamase was identified in any of those isolates. Whole-genome sequence analysis suggested that this resistance was driven by multifactorial mechanisms including mutational changes in iron transporter proteins associated with FDC uptake, ampC gene overproduction, and mexAB-oprM overexpression. These findings highlight that a susceptibility testing to FDC must be performed prior to any prescription.

Characterization of the Achromobacter xylosoxidans Type VI Secretion System and Its Implication in Cystic Fibrosis.

Bacteria of the genus Achromobacter are environmental germs, with an unknown reservoir. It can become opportunistic pathogens in immunocompromised patients, causing bacteremia, meningitis, pneumonia, or peritonitis. In recent years, Achromobacter xylosoxidans has emerged with increasing incidence in patients with cystic fibrosis (CF). Recent studies showed that A. xylosoxidans is involved in the degradation of the respiratory function of patients with CF. The respiratory ecosystem of patients with CF is colonized by bacterial species that constantly fight for space and access to nutrients. The type VI secretion system (T6SS) empowers this constant bacterial antagonism, and it is used as a virulence factor in several pathogenic bacteria. This study aimed to investigate the prevalence of the T6SS genes in A. xylosoxidans isolated in patients with CF. We also evaluated clinical and molecular characteristics of T6SS-positive A. xylosoxidans strains. We showed that A. xylosoxidans possesses a T6SS gene cluster and that some environmental and clinical isolates assemble a functional T6SS nanomachine. A. xylosoxidans T6SS is used to target competing bacteria, including other CF-specific pathogens. Finally, we demonstrated the importance of the T6SS in the internalization of A. xylosoxidans in lung epithelial cells and that the T6SS protein Hcp is detected in the sputum of patients with CF. Altogether, these results suggest for the first time a role of T6SS in CF-lung colonization by A. xylosoxidans and opens promising perspective to target this virulence determinant as innovative theranostic options for CF management.

Comparison of time-to-positivity between two blood culture systems: a detailed analysis down to the genus-level.

A recently developed, automated blood culture system and medium improve the time-to-positivity (TTP) for bacteremia. However, there have thus far been no genus-level analyses using this novel system. We evaluated and compared the changes in blood culture TTP between two systems: BacT/Alert 3D with a blood culture medium containing activated charcoal versus the more recent BacT/Alert Virtuo with a blood culture medium containing polymeric beads. This before-and-after study included blood cultures collected between July 2010 and April 2014 (3D, activated charcoal) and between July 2015 and April 2018 (Virtuo, polymeric beads). A total of 554,732 blood cultures were included, 267,935 (48.30%) during the first period and 286,797 (51.70%) during the second period. Overall, 55,611 (10.02%) tested positive for at least one microorganism. The incubation of the blood culture medium in the Virtuo system was associated with reduced TTP for the most prevalent bacteria, those representing 91.72% (n=51,006) of all the positive blood cultures. The median TTP was reduced by 0.99 h for Staphylococcus, Enterococcus, Streptococcus, Pseudomonadales, and most of the genera within the order Enterobacterales (except the family Morganellaceae). However, strictly anaerobic bacteria belonging to the genus Bacteroides, representing 0.85% (n=474) of all positive blood cultures, were detected 4.53 h later using the Virtuo system. Virtuo was associated with a shorter TTP for most bacteria, but this improvement was heterogeneous to the genus level.

Classification and Regression Trees for Bacterial Vaginosis Diagnosis in Pregnant Women Based on High-Throughput Quantitative PCR.

Bacterial vaginosis (BV) diagnosis in pregnancy is based on the Nugent score, which consists of semiquantitation of bacterial morphotypes. Limited data exist concerning molecular-based diagnosis in asymptomatic pregnant women. Using high-throughput quantitative PCR, 34 microorganisms were screened in asymptomatic pregnant women and compared with the Nugent score. Three-hundred and four vaginal samples had a Nugent score <7 (69.9%) and 131, a Nugent score ≥7 (30.1%), consistent with BV. More pregnant women with BV share Atopobiumvaginae, bacterial vaginosis associated bacteria-2, Gardnerella spp., Mobiluncus curtisii, Mo. mulieris, Mycoplasma hominis, Ureaplasma urealyticum, Prevotella bivia, Megasphaera 1, and Megasphaera 2 in their vaginal sample. Fewer pregnant women with BV share Lactobacillus crispatus, L. gasseri, L. jensenii, and Enterococcus faecalis in their vaginal sample (P < 0.001). Classification and regression tree analysis was performed to determine which combinations of detected bacteria optimally diagnose BV in this population. A set of only four bacteria of 34 microorganisms (A. vaginae, Gardnerella spp., L. crispatus, and P. bivia) was the best combination to identify BV in a cohort of asymptomatic pregnant women, with a sensitivity of 77.1%, and specificity of 97.0% compared with the Nugent score. The quantitative PCR in the present study responds to the limits of the Nugent score by implementing an easily reproducible quantitative assay to assess the absence of BV in pregnancy.

Antibiotic-related gut dysbiosis induces lung immunodepression and worsens lung infection in mice.

BACKGROUND: Gut dysbiosis due to the adverse effects of antibiotics affects outcomes of lung infection. Previous murine models relied on significant depletion of both gut and lung microbiota, rendering the analysis of immune gut-lung cross-talk difficult. Here, we study the effects of antibiotic-induced gut dysbiosis without lung dysbiosis on lung immunity and the consequences on acute P. aeruginosa lung infection. METHODS: C57BL6 mice received 7 days oral vancomycin-colistin, followed by normal regimen or fecal microbial transplant or Fms-related tyrosine kinase 3 ligand (Flt3-Ligand) over 2 days, and then intra-nasal P. aeruginosa strain PAO1. Gut and lung microbiota were studied by next-generation sequencing, and lung infection outcomes were studied at 24 h. Effects of vancomycin-colistin on underlying immunity and bone marrow progenitors were studied in uninfected mice by flow cytometry in the lung, spleen, and bone marrow. RESULTS: Vancomycin-colistin administration induces widespread cellular immunosuppression in both the lung and spleen, decreases circulating hematopoietic cytokine Flt3-Ligand, and depresses dendritic cell bone marrow progenitors leading to worsening of P. aeruginosa lung infection outcomes (bacterial loads, lung injury, and survival). Reversal of these effects by fecal microbial transplant shows that these alterations are related to gut dysbiosis. Recombinant Flt3-Ligand reverses the effects of antibiotics on subsequent lung infection. CONCLUSIONS: These results show that gut dysbiosis strongly impairs monocyte/dendritic progenitors and lung immunity, worsening outcomes of P. aeruginosa lung infection. Treatment with a fecal microbial transplant or immune stimulation by Flt3-Ligand both restore lung cellular responses to and outcomes of P. aeruginosa following antibiotic-induced gut dysbiosis.

Determinants of pregnant women's knowledge about influenza and the influenza vaccine: A large, single-centre cohort study.

INTRODUCTION: Although influenza can lead to adverse outcomes during pregnancy, the level of influenza vaccine coverage among pregnant women remains very low. According to the literature, a high level of knowledge about influenza disease and the influenza vaccine is one of the main determinants of vaccination coverage. The objective of the present study was to describe pregnant women's level of knowledge of these topics and to identify any corresponding determinants. MATERIAL AND METHODS: A prospective, observational, hospital-based study of women having given birth in our university medical centre during the 2014-2015 influenza season. Data were collected through a self-questionnaire or extracted from medical records. Determinants of highest knowledge were identified using logistic regression. RESULTS: Of the 2069 women included in the study, 827 (40%) did not know that influenza can lead to severe adverse outcomes for the mother, and 960 (46%) did not know about possible severe adverse outcomes for the baby. Two hundred and one women (9.8%) stated that the vaccine was "contraindicated" or "unnecessary" during pregnancy. Only 205 women (17%) had been vaccinated during a previous pregnancy. Determinants of the highest level of knowledge were age over 24, a high educational level, previous influenza vaccination, nulliparity, and the recommendation of vaccination by a healthcare professional. CONCLUSIONS: Recommending vaccination during pregnancy appears to increase knowledge about influenza and its vaccine among pregnant women.

Childhood asthma heterogeneity at the era of precision medicine: Modulating the immune response or the microbiota for the management of asthma attack.

Exacerbations are a main characteristic of asthma. In childhood, the risk is increasing with severity. Exacerbations are a strong phenotypic marker, particularly of severe and therapy-resistant asthma. These early-life events may influence the evolution and be involved in lung function decline. In children, asthma attacks are facilitated by exposure to allergens and pollutants, but are mainly triggered by microbial agents. Multiple studies have assessed immune responses to viruses, and to a lesser extend bacteria, during asthma exacerbation. Research has identified impairment of innate immune responses in children, related to altered pathogen recognition, interferon release, or anti-viral response. Influence of this host-microbiota dialog on the adaptive immune response may be crucial, leading to the development of biased T helper (Th)2 inflammation. These dynamic interactions may impact the presentations of asthma attacks, and have long-term consequences. The aim of this review is to synthesize studies exploring immune mechanisms impairment against viruses and bacteria promoting asthma attacks in children. The potential influence of the nature of infectious agents and/or preexisting microbiota on the development of exacerbation is also addressed. We then discuss our understanding of how these diverse host-microbiota interactions in children may account for the heterogeneity of endotypes and clinical presentations. Finally, improving the knowledge of the pathophysiological processes induced by infections has led to offer new opportunities for the development of preventive or curative therapeutics for acute asthma. A better definition of asthma endotypes associated with precision medicine might lead to substantial progress in the management of severe childhood asthma.

Severe preschool asthmatics have altered cytokine and anti-viral responses during exacerbation.

BACKGROUND: Preschool asthma/recurrent wheeze is a heterogeneous condition. Different clinical phenotypes have been described, including episodic viral wheeze (EVW), severe intermittent wheeze (SIW), and multiple-trigger wheeze (MTW). OBJECTIVE: To compare clinical, viral, and inflammatory/immune profiling at exacerbation between MTW, SIW, and EVW phenotypes. METHODS: Multicenter, prospective, observational cohort (VIRASTHMA-2). Children (1-5 years) with preschool asthma were enrolled during hospitalization for a severe exacerbation. History and anamnestic data, plasma, and nasal samples were collected at exacerbation (T1) and at steady state, 8 weeks later (T2), and sputum samples were collected at T1. RESULTS: A total of 147 children were enrolled, 37 (25%) had SIW, 18 (12.2%) EVW, and 92 (63%) MTW. They were atopic (47%), exposed to mold (22%) and cigarette smoke (50%), and prone to exacerbations (≥2 in the previous year in 70%). At exacerbation, at least one virus was isolated in 94% and rhinovirus in 75%, with no difference between phenotypes. Children with MTW and SIW phenotypes displayed lower plasma concentrations of IFN-γ (P = .002), IL-5 (P = .020), TNF-α (P = .038), IL-10 (P = .002), IFN-ß (P = .036), and CXCL10 (P = .006) and lower levels of IFN-γ (P = .047) in sputum at exacerbation than children with EVW. At T2, they also displayed lower plasma levels of IFN-γ (P = .045) and CXCL10 (P = .013). CONCLUSION: Among preschool asthmatic children, MTW and SIW, prone to exacerbations, display lower systemic levels of Th1, Th2 cytokines, pro- and anti-inflammatory cytokines, and antiviral responses during severe virus-induced exacerbation.

Clinical relevance of Clostridium bacteremia: An 8-year retrospective study.

Clostridium spp. are recovered from 25% of the blood culture positive with anaerobes. However, the clinical relevance of Clostridium bacteremia has been controverted in the literature, particularly for C. perfringens. We aimed to evaluate the clinical relevance of Clostridium bacteremia, either due to C. perfringens or other Clostridium species, and to identify the risk factors of mortality in these patients. A retrospective cohort study was conducted from January 2010 to April 2018. All the patients with at least one blood culture positive with any Clostridium species were included. Eighty-one patients with a least one blood culture positive with any Clostridium species were included. Seventy patients (86.4%) fulfilled the criteria for clinically relevant bacteremia. Bacteremia due to C. perfringens tended to be less clinically relevant than other Clostridium species but this was not statistically significant (76% vs 91.2%, P = 0.09). In case of clinically relevant bacteremia, the 30-day mortality rate was 31.4%. In multivariate analysis, adequate empiric antimicrobial therapy was significantly associated with survival (P = 0.03). In conclusion, bacteremia due to C. perfringens or other Clostridium species is usually clinically relevant. This finding was also supported by an improved survival at 30 days when adequate empiric antimicrobial therapy was administered.

Determinants of influenza vaccination uptake in pregnancy: a large single-Centre cohort study.

BACKGROUND: Although vaccination of pregnant women against influenza is recommended, the vaccination rate remains low. We conducted a study to identify determinants of influenza vaccination uptake in pregnancy in order to identify strategies to improve seasonal influenza vaccination rates. METHODS: Prospective observational hospital-based study in the French hospital performing the highest number of deliveries, located in the city of Lille, among all women who had given birth during the 2014-2015 influenza season. Data were collected through a self-completed questionnaire and from medical files. The vaccination uptake was self-reported. Determinants of vaccination uptake were identified using logistic regression analysis. RESULTS: Of the 2045 women included in the study, 35.5% reported that they had been vaccinated against influenza during their pregnancy. The principal factors significantly associated with greater vaccination uptake were previous influenza vaccination (50.9% vs 20.2%, OR 4.1, 95% CI 3.1-5.5), nulliparity (41.0% vs 31.3%, OR 2.5, 95% CI 1.7-3.7), history of preterm delivery < 34 weeks (43.4% vs 30.3%, OR 2.3, 95% CI 1.1-4.9), the mother's perception that the frequency of vaccine complications for babies is very low (54.6% vs 20.6%, OR 1.1, 95% CI 0.5-2.2), the mother's good knowledge of influenza and its vaccine (61.7% vs 24.4%, OR 3.1, 95% CI 2.2-4.4), hospital-based prenatal care in their first trimester of pregnancy (55.0% vs 30.2%, OR 2.1, 95% CI 1.2-3.7), vaccination recommendations during pregnancy by a healthcare worker (47.0% vs 2.7%, OR 18.8, 95% CI 10.0-35.8), receipt of a vaccine reimbursement form (52.4% vs 18.6%, OR 2.0, 95% CI 1.5-2.7), and information from at least one healthcare worker about the vaccine (43.8% vs 19.1%, OR 1.8, 95% CI 1.3-2.6). CONCLUSIONS: Our findings suggest that in order to increase flu vaccination compliance among pregnant women, future public health programmes must ensure cost-free access to vaccination, and incorporate education about the risks of influenza and the efficacy/safety of vaccination and clear recommendations from healthcare professionals into routine antenatal care.

Recurrent Pneumococcal Meningitis in Children: A Multicenter Case-control Study.

BACKGROUND: Pneumococcal meningitis (PM) is a serious disease that can rarely recur at a later time after the initial episode. METHODS: A retrospective multicenter case-control study was conducted with data for children 18 years of age or younger obtained from the National Observatory of Bacterial Meningitis in Children between January 2001 and September 2015. Cases were all patients with RPM. Each case was matched with 2 randomized controls with a single PM episode in the year of the first episode of PM in the case and born the same year. Case and control data were compared. RESULTS: Among the 1634 PM episodes in children 18 years of age or younger, 24 (1.5%) children had RPM. RPM cases were significantly less frequent than single PM cases in winter (27% vs. 48%; P=0.03) and showed significantly less concomitant ear, nose and throat infections when considering the first episode (30% vs. 56%, P = 0.04) and all episodes (28% vs. 56%, P < 0.01). Cerebrospinal fluid leakage was frequent in RPM cases versus controls (83% vs. 10%, P < 0.01), including 25% discovered after the third PM episode. Immune deficiency was absent in cases and present in 15% of controls. Cases and controls did not differ in death rate or neurologic outcome. CONCLUSIONS: RPM is rare in children. Cerebrospinal fluid leakage must be considered.

Differential risk of severe infection in febrile neutropenia among children with blood cancer or solid tumor.

OBJECTIVE: To describe and analyze the differences between infections in children with febrile neutropenia (FN) treated for solid tumor or blood cancer. METHODS: A prospective study included all episodes of FN in children from April 2007 to April 2016 in 2-pediatric cancer centers in France. Medical history, clinical and laboratory data available at admission and final microbiological data were collected. The proportion of FN, severe infection, categories of microorganisms and outcomes were compared between the two groups. The presumed gateway of the infection was a posteriori considered and evaluated. RESULTS: We analyzed 1197 FN episodes (mean age: 8 years). 66% of the FN episodes occurred in children with blood cancer. Severe infections were identified in 23.4% of episodes overall. The rate of severe infection (28.4% vs. 10.4%), types of microorganisms and the need for a management in intensive care unit (2.6% vs. 0.5%) was significantly different between children with blood cancer and solid tumor. Digestive or respiratory presumed gateway of the infections was less frequent for patients with solid tumor. CONCLUSION: Given these important microbiological and clinical differences, it may be appropriate to consider differently the risk of severe infection in these two populations and therefore the management of FN.

Clostridium ventriculi bacteremia following acute colonic pseudo-obstruction: A case report.

Clostridium ventriculi (formerly Sarcina ventriculi) is a Gram-positive, obligate anaerobic coccus. Human infections due to this bacterium have rarely been reported, its involvement in the development of gastric ulcers and perforation has been suggested. We present a case of bacteremia due to C. ventriculi following acute colonic pseudo-obstruction.

Impact of the Timing of Antibiotic Administration on Digestive Colonization with Carbapenemase-Producing Enterobacteriaceae in a Murine Model.

While antibiotic use is a risk factor of carbapenemase-producing Enterobacteriaceae (CPE) acquisition, the importance of timing of antibiotic administration relative to CPE exposure remains unclear. In a murine model of gut colonization by New Delhi metallo-beta-lactamase-1 (NDM-1)-producing Klebsiella pneumoniae, a single injection of clindamycin within at most 1 week before or after CPE exposure induced colonization persisting up to 100 days. The timing of antibiotic administration relative to CPE exposure may be relevant to infection control and antimicrobial stewardship approaches.

Draft Genome Sequences of Two Pseudomonas aeruginosa Multidrug-Resistant Clinical Isolates, PAL0.1 and PAL1.1.

Pseudomonas aeruginosa infections are challenging due to intrinsic and acquired resistance mechanisms. We report here the draft genome sequences of two multidrug-resistant strains-PAL0.1, isolated from the airways of an intensive care unit (ICU) patient with ventilator-associated pneumonia, and PAL1.1, isolated from blood cultures of an ICU patient with sepsis.