EEF2-inactivating toxins engage the NLRP1 inflammasome and promote epithelial barrier disruption.

Human airway and corneal epithelial cells, which are critically altered during chronic infections mediated by Pseudomonas aeruginosa, specifically express the inflammasome sensor NLRP1. Here, together with a companion study, we report that the NLRP1 inflammasome detects exotoxin A (EXOA), a ribotoxin released by P. aeruginosa type 2 secretion system (T2SS), during chronic infection. Mechanistically, EXOA-driven eukaryotic elongation factor 2 (EEF2) ribosylation and covalent inactivation promote ribotoxic stress and subsequent NLRP1 inflammasome activation, a process shared with other EEF2-inactivating toxins, diphtheria toxin and cholix toxin. Biochemically, irreversible EEF2 inactivation triggers ribosome stress-associated kinases ZAKα- and P38-dependent NLRP1 phosphorylation and subsequent proteasome-driven functional degradation. Finally, cystic fibrosis cells from patients exhibit exacerbated P38 activity and hypersensitivity to EXOA-induced ribotoxic stress-dependent NLRP1 inflammasome activation, a process inhibited by the use of ZAKα inhibitors. Altogether, our results show the importance of P. aeruginosa virulence factor EXOA at promoting NLRP1-dependent epithelial damage and identify ZAKα as a critical sensor of virulence-inactivated EEF2.

Management of initial colonisations with Burkholderia species in France, with retrospective analysis in five cystic fibrosis Centres: a pilot study.

BACKGROUND: Whereas Burkholderia infections are recognized to impair prognosis in cystic fibrosis (CF) patients, there is no recommendation to date for early eradication therapy. The aim of our study was to analyse the current management of initial colonisations with Burkholderia cepacia complex (BCC) or B. gladioli in French CF Centres and its impact on bacterial clearance and clinical outcome. METHODS: We performed a retrospective review of the primary colonisations (PC), defined as newly positive sputum cultures, observed between 2010 and 2018 in five CF Centres. Treatment regimens, microbiological and clinical data were collected. RESULTS: Seventeen patients (14 with BCC, and 3 with B. gladioli) were included. Eradication therapy, using heterogeneous combinations of intravenous, oral or nebulised antibiotics, was attempted in 11 patients. Six out of the 11 treated patients, and 4 out of the 6 untreated patients cleared the bacterium. Though not statistically significant, higher forced expiratory volume in 1 second and forced vital capacity at PC and consistency of treatment with in vitro antibiotic susceptibility tended to be associated with eradication. The management of PC was shown to be heterogeneous, thus impairing the statistical power of our study. Large prospective studies are needed to define whom to treat, when, and how. CONCLUSIONS: Pending these studies, we propose, due to possible spontaneous clearance, to check the presence of Burkholderia 1 month after PC before starting antibiotics, at least in the milder cases, and to evaluate a combination of intravenous beta-lactam + oral or intravenous fluoroquinolone + inhaled aminoglycoside.

The Surface Microbiome of Clinically Unaffected Skinfolds in Hidradenitis Suppurativa: A Cross-Sectional Culture-Based and 16S rRNA Gene Amplicon Sequencing Study in 60 Patients.

Hidradenitis suppurativa (HS) is a chronic inflammatory disease of the skin associated with specific lesional dysbiotic features. We studied the microbiome of clinically unaffected typical HS sites (armpits, inguinal folds, and gluteal clefts) in 60 patients with HS and 17 healthy controls. A total of 192 samples obtained by swabbing were analyzed by bacterial cultures. Of these, 116 randomly selected samples were studied by 16S rRNA gene amplicon sequencing. Patients and controls showed similar characteristics, except for smoking (87% vs. 6%, respectively). HS skinfolds were characterized by an increased abundance of anaerobes, predominantly Prevotella, but also Actinomyces, Campylobacter ureolyticus, and Mobiluncus, contrasting with a lower abundance of skin commensals such as Staphylococcus epidermidis, a major component of the skin microbiome; Kocuria; and Micrococcus luteus. The following three independent factors were associated with an abundance of high anaerobes by multivariate analysis: samples originating from patients with HS patients (P = 2.1 × 10-4); body mass index (P = 5 × 10-5); and the sampling site, the gluteal cleft being the most anaerobic area, followed by inguinal folds and axilla (P = 3 × 10-6). The microbiome of clinically unaffected HS skinfolds is reminiscent, albeit to a minor extent, of the microbiome of chronic suppurative HS lesions and may fuel inflammation at a preclinical stage of the disease.

Pseudomonas aeruginosa bloodstream infections in children: a 9-year retrospective study.

P. aeruginosa bloodstream infection (BSI) is associated with high hospital mortality. Empirical combination therapy is commonly used, but its benefit remains debated. The purpose of this study was to describe in a paediatric population, demographical characteristics and outcome of children treated for P. aeruginosa BSI receiving either a combined or single antibacterial therapy. We performed a retrospective, single-centre, cohort study of hospitalized children with P. aeruginosa BSI from 2007 to 2015. A total of 118 bloodstream infections (BSI) were analysed (102 (86.4%) hospital-acquired, including 52 (44.1%) hospitalized in intensive care unit). In immunocompromised children, 52% of BSI episodes were recorded. Recent medical history revealed that 68% were hospitalized, 31% underwent surgery and 67% had a prior antibiotic therapy within the last 3 months. In-hospital mortality was similar for patients receiving single or combined anti-Pseudomonas therapy (p = 0.78). In multivariate analysis, independent risk factors for in-hospital mortality were neutropenia (OR = 6.23 [1.94-20.01], hospitalization in ICU (OR = 5.24 [2.04-13.49]) and urinary tract infection (OR = 4.40 [1.02-19.25]).Conclusion: P. aeruginosa BSI mainly occurred in immunocompromised children. Most infections were hospital-acquired and associated with high mortality. Combination therapy did not improve survival. What is Known: • P. aeruginosa bloodstream infection (BSI) is associated with high hospital mortality. Empirical combination therapy is commonly used but its benefit remains debated. What is New: • This is the largest cohort of Pseudomonas aeruginosa bacteraemia in children ever published. P. aeruginosa Bloodstream mainly occurred in immunocompromised children. Most infections were hospital-acquired and associated with high mortality. Combination therapy did not improve survival.

Nontuberculous lymphadenitis in children: What management strategy?

OBJECTIVES: Nontuberculous mycobacterial (NTM) lymphadenitis is a rare disease of children under 5 years. Its treatment is not standardized, even a "wait-and-see" approach is shown to be effective in the literature. Here, we discuss the diagnostic and therapeutic strategies employed in our departments. METHODS: Records of pediatric patients treated for NTM cervical lymphadenitis from 2010 to 2015 in our tertiary center were retrospectively reviewed. Patients underwent cervical echotomography and/or CT scan. Every patient but one had microbiological explorations (NTM polymerase chain reaction [PCR] and culture) on fine needle aspiration of pus and/or adenitis biopsy. Differential diagnoses (tuberculosis, cat scratch disease) were excluded with serologies, chest X-Ray, and PCR on adenitis samples. Patients were classified as "proven diagnosis" (NTM detected), "highly probable" (suggestive clinical and anatomopathological aspect) or "possible" infection (suggestive adenitis alone). Treatments, follow-up and adverse events were reviewed. RESULTS: Thirty-one patients were treated for NTM, median age 2.40 years (Interquartile Range IQR = [1.85-3.16]). Twenty-nine patients (96.77%) had an isolated cervico-facial localization. Median follow-up was 8.00 months (IQR = [4.20-13.43]). We found 17 "proven diagnosis" (58.62%), 5 "highly probable" (17.24%) and 7 "possible" infections (24.14%). "Proven" infections were due to: Mycobacterium avium (n = 12, 66.67%) and M. intracellulare (n = 5, 27.78%). All 29 patients received antibiotics, which were effective for 10 (34.48%, group 1); 10 underwent surgical excision for a poor outcome with antibiotics (34.48%, group 2); spontaneous or surgical drainage occurred in 9 on antibiotics (31.03%, group 3). The median times to resolution for group 1, 2 and 3 were respectively 6.33 months, 6.22 months and 9.53 months. Antibiotics treatment was mostly clarithromycin (n = 27, 93.10%) and/or rifampicin (n = 19, 65.52%); 18 patients (62.07%) received both. Median antibiotics duration was 6.23 months (IQR = [5.17-7.46]), with good compliance (79.31%). The observed adverse effects were 3 (13.04%) isolated transient transaminase elevations, 1 case (4.35%) of minor creatinine elevation, and 1 case (4.35%) of transient diarrhea. Surgical drainage caused 1 transient marginal mandibular nerve palsy, resolutive after 1 month. CONCLUSION: Antibiotics in NTM adenitis lead to resolution in 7 months, with good tolerance and compliance. The efficacy of "wait-and-see" attitude in the literature make excision surgery a second line treatment.

Efficacy of ertapenem in severe hidradenitis suppurativa: a pilot study in a cohort of 30 consecutive patients.

OBJECTIVES: Hidradenitis suppurativa (HS) is an inflammatory skin disease typically localized in the axillae and inguinal and perineal areas. In the absence of standardized medical treatment, severe HS patients present chronic suppurative lesions with polymicrobial anaerobic abscesses. Wide surgery is the cornerstone treatment of severe HS, but surgical indications are limited by the extent of lesions. Intravenous broad-spectrum antibiotics may help control HS, but their efficacy is not documented. This study was designed to assess the efficacy of a 6 week course of ertapenem (1 g daily) and of antibiotic consolidation treatments for 6 months (M6) in severe HS. PATIENTS AND METHODS: Thirty consecutive patients with severe HS were retrospectively included in this study. The clinical severity of HS was assessed using the Sartorius score, which takes into account the number and severity of lesions. RESULTS: The median (IQR) Sartorius score dropped from 49.5 (28-62) at baseline to 19.0 (12-28) after ertapenem (P < 10(-4)). Five patients were lost to follow-up thereafter. At M6 the Sartorius score further decreased for the 16 patients who received continuous consolidation treatments, since 59% of HS areas reached clinical remission at M6 (i.e. absence of any inflammatory symptoms, P < 10(-4)). Nine patients interrupted or received intermittent consolidation treatments due to poor observance or irregular follow-up. Their Sartorius score stopped improving or returned to baseline. No major adverse event occurred. CONCLUSIONS: Ertapenem can dramatically improve severe HS. Consolidation treatments are needed to further improve HS and are mandatory to prevent relapses. Combined with surgery, optimized antibiotic treatments may be promising in severe HS.