Growth periodicity in semi-deciduous tropical tree species from the Congo Basin

In the tropics, more precisely in equatorial dense rainforest, xylogenesis is driven by a little distinct climatological seasonality, and many tropical trees do not show clear growth rings. This makes retrospective analyses and modeling of future tree performance difficult. This research investigates the presence, the distinctness, and the periodicity of growth ring for dominant tree species in two semi-deciduous rainforests, which contrast in terms of precipitation dynamics. Eighteen tree species common to both forests were investigated. We used the cambial marking technique and then verified the presence and periodicity of growth-ring boundaries in the wood produced between pinning and collection by microscopic and macroscopic observation. The study showed that all eighteen species can form visible growth rings in both sites. However, the periodicity of ring formation varied significantly within and between species, and within sites. Trees from the site with clearly defined dry season had a higher likelihood to form periodical growth rings compared to those from the site where rainfall seasonality is less pronounced. The distinctness of the formed rings however did not show a site dependency. Periodical growth-ring formation was more likely in fast-growing trees. Furthermore, improvements can be made by a detailed study of the cambial activity through microcores taken at high temporal resolution, to get insight on the phenology of the lateral meristem.

Consistent patterns of common species across tropical tree communities

Trees structure the Earth's most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1-6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth's 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world's most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.

Protecting an artificial savanna as a nature-based solution to restore carbon and biodiversity in the Democratic Republic of the Congo

A large share of the global forest restoration potential is situated in artificial 'unstable' mesic African savannas, which could be restored to higher carbon and biodiversity states if protected from human-induced burning. However, uncertainty on recovery rates in protected unstable savannas impedes science-informed forest restoration initiatives. Here, we quantify the forest restoration success of anthropogenic fire exclusion within an 88-ha mesic artificial savanna patch in the Kongo Central province of the Democratic Republic of the Congo (DR Congo). We found that aboveground carbon recovery after 17 years was on average 11.40 ± 0.85 Mg C ha-1 . Using a statistical model, we found that aboveground carbon stocks take 112 ± 3 years to recover to 90% of aboveground carbon stocks in old-growth forests. Assuming that this recovery trajectory would be representative for all unstable savannas, we estimate that they could have a total carbon uptake potential of 12.13 ± 2.25 Gt C by 2100 across DR Congo, Congo and Angola. Species richness recovered to 33.17% after 17 years, and we predicted a 90% recovery at 54 ± 2 years. In contrast, we predicted that species composition would recover to 90% of old-growth forest composition only after 124 ± 3 years. We conclude that the relatively simple and cost-efficient measure of fire exclusion in artificial savannas is an effective nature-based solution to climate change and biodiversity loss. However, more long-term and in situ monitoring efforts are needed to quantify variation in long-term carbon and diversity recovery pathways. Particular uncertainties are spatial variability in socio-economics and growing conditions as well as the effects of projected climate change.

Microbiota promotes recruitment and pro-inflammatory response of caecal macrophages during E. tenella infection

BACKGROUND

Eimeria genus belongs to the apicomplexan parasite phylum and is responsible for coccidiosis, an intestinal disease with a major economic impact on poultry production. Eimeria tenella is one of the most virulent species in chickens. In a previous study, we showed a negative impact of caecal microbiota on the physiopathology of this infection. However, the mechanism by which microbiota leads to the physiopathology remained undetermined. Macrophages play a key role in inflammatory processes and their interaction with the microbiota during E. tenella infection have never been investigated. We therefore examined the impact of microbiota on macrophages during E. tenella infection. Macrophages were monitored in caecal tissues by immunofluorescence staining with KUL01 antibody in non-infected and infected germ-free and conventional chickens. Caecal cells were isolated, stained, analyzed and sorted to examine their gene expression using high-throughput qPCR.

RESULTS

We demonstrated that microbiota was essential for caecal macrophage recruitment in E. tenella infection. Furthermore, microbiota promoted a pro-inflammatory transcriptomic profile of macrophages characterized by increased gene expression of NOS2, ACOD1, PTGS2, TNFα, IL1β, IL6, IL8L1, IL8L2 and CCL20 in infected chickens. Administration of caecal microbiota from conventional chickens to germ-free infected chickens partially restored macrophage recruitment and response.

CONCLUSIONS

Taken together, these results suggest that the microbiota enhances the physiopathology of this infection through macrophage recruitment and activation. Consequently, strategies involving modulation of the gut microbiota may lead to attenuation of the macrophage-mediated inflammatory response, thereby limiting the negative clinical outcome of the disease.

Personalized bacteriophage therapy to treat pandrug-resistant spinal Pseudomonas aeruginosa infection

Bone and joint infections (BJI) are one of the most difficult-to-treat bacterial infection, especially in the era of antimicrobial resistance. Lytic bacteriophages (phages for short) are natural viruses that can selectively target and kill bacteria. They are considered to have a high therapeutic potential for the treatment of severe bacterial infections and especially BJI, as they also target biofilms. Here we report on the management of a patient with a pandrug-resistant Pseudomonas aeruginosa spinal abscess who was treated with surgery and a personalized combination of phage therapy that was added to antibiotics. As the infecting P. aeruginosa strain was resistant to the phages developed by private companies that were contacted, we set up a unique European academic collaboration to find, produce and administer a personalized phage cocktail to the patient in due time. After two surgeries, despite bacterial persistence with expression of small colony variants, the patient healed with local and intravenous injections of purified phages as adjuvant therapy.

Here, the authors describe a patient with a pandrug-resistant Pseudomonas aeruginosa spinal abscess successfully treated with a personalized combination of phage therapy and antibiotics.

Evaluation of the MRSA/SA ELITe MGB Assay for the Detection of Staphylococcus aureus in Bone and Joint Infections

Bone and joint infections represent a potentially devastating complication of prosthetic orthopedic joint replacement, thus requiring both rapid and appropriate antibiotic treatment. Staphylococcus aureus is one of the most common pathogens involved in this pathology. Being able to assert its presence is the first step of efficient patient management. This monocenter study evaluated the MRSA/SA ELITe MGB assay for the molecular detection of S. aureus and methicillin-resistant S. aureus (MRSA) in bone and joint biopsy specimens and synovial fluids. This test, together with conventional techniques, including standard cultures and the 16S rRNA amplification assay, was performed on 208 successive perioperative samples collected prospectively for 1 year obtained from 129 patients. Using conventional techniques, we detected a microbial pathogen in 76 samples from 58 patients, 40 of which were identified as S. aureus. The limit of detection (LOD) of the MRSA/SA ELITe MGB assay was experimentally determined for bone and joint biopsy specimens and synovial fluids using negative samples spiked with S. aureus ATCC 43300. The sensitivities of S. aureus detection with the MRSA/SA ELITe MGB assay were 82.5% (33/40 samples) and 97.5% (39/40 samples) using the manufacturer's LOD and an experimentally determined LOD, respectively. Interestingly, using the osteoarticular specific LOD, 15 additional samples were determined to be positive for S. aureus DNA with the MRSA/SA ELITe MGB assay; in all cases, these samples were obtained from patients considered to be infected with S. aureus according to their clinical and microbiological records. The results were available within 24 h, which could help to expedite therapeutic decisions.

Tolerance and microbiological efficacy of cefepime or piperacillin/tazobactam in combination with vancomycin as empirical antimicrobial therapy of prosthetic joint infection: a propensity-matched cohort study

BACKGROUND

The use of piperacillin/tazobactam with vancomycin as empirical antimicrobial therapy (EAT) for prosthetic joint infection (PJI) has been associated with an increased risk of acute kidney injury (AKI), leading us to propose cefepime as an alternative since 2017 in our reference centre.

OBJECTIVES

To compare microbiological efficacy and tolerance of these two EAT strategies.

METHODS

All adult patients with PJI empirically treated with vancomycin+cefepime (n = 89) were enrolled in a prospective observational study and matched with vancomycin+piperacillin/tazobactam-treated historical controls (n = 89) according to a propensity score including age, baseline renal function and concomitant use of other nephrotoxic agents. The two groups were compared using Kaplan-Meier curve analysis, and non-parametric tests regarding the proportion of efficacious empirical regimen and the incidence of empirical therapy-related adverse events (AE).

RESULTS

Among 146 (82.0%) documented infections, the EAT was considered efficacious in 77 (98.7%) and 65 (98.5%) of the piperacillin/tazobactam- and cefepime-treated patients, respectively (P = 1.000). The rate of AE, particularly AKI, was significantly higher in the vancomycin+piperacillin/tazobactam group [n = 27 (30.3%) for all AE and 23 (25.8%) for AKI] compared with the vancomycin+cefepime [n = 13 (14.6%) and 6 (6.7%)] group (P = 0.019 and <0.001, respectively), leading to premature EAT discontinuation in 20 (22.5%) and 5 (5.6%) patients (P = 0.002). The two groups were not significantly different regarding their comorbidities, and AKI incidence was not related to vancomycin plasma overexposure.

CONCLUSIONS

Based on the susceptibility profile of bacterial isolates from included patients, microbiological efficacy of both strategies was expected to be similar, but vancomycin + cefepime was associated with a significantly lower incidence of AKI.

Epidemiology and clinical characteristics of Klebsiella spp. meningitis in France

OBJECTIVES

To describe the epidemiology of Klebsiella spp. meningitis in France with respect to clinical and bacteriological data.

METHODS

We performed a four-year multicenter, retrospective, observational study. The primary objective was to provide a clinical description of patients with Klebsiella spp. meningitis. Secondary objectives were to compare community-acquired meningitis and healthcare-associated meningitis and to analyze factors associated with mortality.

RESULTS

We enrolled 131 patients with Klebsiella spp. meningitis. Eighty-two (62.6%) infections were reported following neurosurgery. Twenty-eight strains (21.4%) were resistant to third-generation cephalosporins (3GC). The median [IQR] cellularity was 980/mm³ [116-5,550], the median protein level was 5.67 [1.62-9] g/L and the median CSF glucose level was 2.5 [0-3.4] mmol/L. The in-hospital mortality rate was 23.6%. Community-acquired meningitis isolates were more frequently susceptible to 3GC than isolates from healthcare-associated meningitis (89.2% versus 72%; p=0.04). Comorbidities reported for patients with community-acquired meningitis were mainly diabetes mellitus and liver cirrhosis. In multivariate analysis, focal neurological disorder at the time of diagnosis was the only factor associated with in-hospital mortality (p=0.01).

CONCLUSIONS

Purulent meningitis caused by Klebsiella spp. needs to be considered in patients with community-acquired meningitis and pre-existing conditions, as well as in case of meningitis following neurosurgical procedures.

Calcul de taille d’étude pour le développement d’un modèle de prédiction d’une aggravation d’une forme légère de COVID-19

Introduction

Le calcul de la taille d’étude pour le développement d’un modèle de prédiction clinique utilise encore souvent la règle empirique proposée par Peduzzi en 1996 qui recommande l’inclusion de 10 événements à prédire par paramètre envisagé dans le modèle de prédiction. Une nouvelle approche a été proposée par Riley et al. en 2020 pour répondre aux enjeux majeurs du développement d’un modèle de prédiction : précision des estimations et contrôle de l’optimisme sur les performances de prédiction. Nous rapportons ici l’application de cette approche pour le développement d’un modèle de prédiction combinant des facteurs cliniques, biologiques et d’imagerie pour prédire la survenue d’une aggravation d’une forme légère de COVID-19 chez des patients ayant des résultats d’imagerie thoracique compatibles ou typiques de la COVID-19.

Méthodes

La stratégie de modélisation envisagée était un modèle de régression logistique avec une sélection a priori de facteurs identifiés dans la littérature. Comme dans la règle empirique, la nouvelle approche nécessite de préciser l’incidence de l’événement à prédire et le nombre de paramètres envisagés dans le modèle de prédiction. La taille d’étude déterminée par cette approche doit satisfaire quatre critères : précision souhaitée pour l’incidence de l’événement ; précision souhaitée pour les prédictions individuelles (sous la forme d’un pourcentage d’erreur absolu moyen) ; niveau maximal souhaité de sur-ajustement aux données (facteur de réduction minimal) et d’optimisme (surestimation maximale du R² de Nagelkerke). Pour les deux derniers critères, le calcul requiert de préciser le R² de Cox–Snell qui, en l’absence d’éléments probants dans la littérature, peut être déterminé en faisant une hypothèse sur le niveau de performance attendu du modèle de prédiction en termes de pourcentage de la variation totale observée dans les données expliqué par le modèle.

Résultats

L’incidence de l’évènement à prédire a été fixée à 20 % selon les données de la littérature. Une revue de la littérature sur les modèles de prédiction développés dans le contexte d’infection à COVID-19 nous a conduits à envisager 16 paramètres dans le modèle. Nous avons suivi les recommandations des auteurs pour définir la précision souhaitée pour l’incidence d’événement (±0,05), le pourcentage d’erreur absolu moyen (5 %), le facteur de réduction minimal (³ 0,9) et la surestimation maximale du critère de performance (£ 0,05). Nous avons fait varier le pourcentage de la variation totale observée dans les données expliqué par le modèle entre 10 et 50 %. Pour satisfaire l’ensemble des critères, la taille d’étude requise variait entre 587 et 2205 patients. Nous avons retenu l’hypothèse d’un pourcentage de variance expliqué de 25 % conduisant à l’inclusion de 829 patients pour le développement du modèle.

Conclusion

La nouvelle approche de calcul de taille d’étude permet de considérer dès la conception, des éléments majeurs qui favorisent le développement d’un modèle de prédiction clinique de qualité, en particulier la précision des probabilités individuelles de survenue de l’événement et le contrôle de l’optimisme. En contrepartie, elle nécessite une expertise statistique plus poussée que pour la règle empirique. Néanmoins, son application est possible même dans un délai court et devrait donc être systématiquement envisagée dans les études de développement d’un modèle de prédiction clinique.

Artificial intelligence solution to classify pulmonary nodules on CT

PURPOSE

The purpose of this study was to create an algorithm to detect and classify pulmonary nodules in two categories based on their volume greater than 100 mm³ or not, using machine learning and deep learning techniques.

MATERIALS AND METHOD

The dataset used to train the model was provided by the organization team of the SFR (French Radiological Society) Data Challenge 2019. An asynchronous and parallel 3-stages pipeline was developed to process all the data (a data "pre-processing" stage; a "nodule detection" stage; a "classifier" stage). Lung segmentation was achieved using 3D U-NET algorithm; nodule detection was done using 3D Retina-UNET and classifier stage with a support vector machine algorithm on selected features. Performances were assessed using area under receiver operating characteristics curve (AUROC).

RESULTS

The pipeline showed good performance for pathological nodule detection and patient diagnosis. With the preparation dataset, an AUROC of 0.9058 (95% confidence interval [CI]: 0.8746-0.9362) was obtained, 87% yielding accuracy (95% CI: 84.83%-91.03%) for the "nodule detection" stage, corresponding to 86% specificity (95% CI: 82%-92%) and 89% sensitivity (95% CI: 84.83%-91.03%).

CONCLUSION

A fully functional pipeline using 3D U-NET, 3D Retina-UNET and classifier stage with a support vector machine algorithm was developed, resulting in high capabilities for pulmonary nodule classification.

RETRAIT : COVID-19 et troubles du rythme

L’éditeur a le regret de vous informer que cet article a déjà été publié dans les Annales de cardiologie et d’angéiologie : https://doi.org/10.1016/j.ancard.2020.09.024 , cette seconde publication faite par erreur a été retirée.

Vous pouvez consulter le site https://www.elsevier.com/about/our-business/policies/article-withdrawal pour de plus amples renseignements.

L’éditeur vous prie d’accepter ses excuses pour ce désagrément.

Efficacy of generic meropenem products in combination with colistin in carbapenemase-producing Klebsiella pneumoniae experimental osteomyelitis

Guidelines for the management of carbapenemase-producing Enterobacterales (CPE) infections recommend a combination of two active agents, including meropenem if the minimum inhibitory concentration (MIC) is ≤8 mg/L. The therapeutic equivalence of meropenem generics has been challenged. We compared the bactericidal activity of meropenem innovator (AstraZeneca) and four generic products (Actavis, Kabi, Mylan and Panpharma), both in vitro and in vivo, in association with colistin. In vitro time-kill studies were performed at 4 × MIC. An experimental model of KPC-producing Klebsiella pneumoniae osteomyelitis was induced in rabbits by tibial injection of a sclerosing agent followed by 2 × 10⁸ CFU of K. pneumoniae KPC-99YC (meropenem MIC = 4 mg/L; colistin MIC = 1 mg/L). At 14 days after inoculation, treatment for 7 days started in seven groups of ≥10 rabbits, including a control group, a colistin group, and one group for each meropenem product (i.e. the innovator and four generics), in combination with colistin. In vitro, meropenem + colistin was bactericidal with no viable bacteria after 6 h, and this effect was similar with all meropenem products. In the osteomyelitis model, there was no significant difference between meropenem generics and the innovator when combined with colistin. Colistin-resistant strains were detected after treatment with colistin + meropenem innovator (n = 3) and generics (n = 3). The efficacy of four meropenem generics did not differ from the innovator in vitro and in an experimental rabbit model of KPC-producing K. pneumoniae osteomyelitis in terms of bactericidal activity and the emergence of resistance.

Repeated introduction and spread of the MRSA clone t304/ST6 in northern Europe

OBJECTIVES

During the last decades several methicillin-resistant Staphylococcus aureus (MRSA) clones with the capability of global spread have emerged in the community. Here, we have investigated a large collection of clinical isolates belonging to MRSA clone t304/ST6, which has emerged in many European countries over the last years, in order to retrace its phylogeny and its spread.

METHODS

We characterized 466 ST6 isolates from Denmark (n = 354), France (n = 10), Norway (n = 24), Sweden (n = 27) and the UK (n = 51). All had spa-type t304 (n = 454) or t304-related spa-types (n = 12) and whole genome sequencing (WGS) was carried out on Illumina Miseq or Hiseq with 100-300 bp reads. cgMLST was performed using Ridom SeqSphere.

RESULTS

A minimum spanning tree (MST) of all 466 isolates showed one large cluster including 182 isolates collected only from Denmark and related to a long-term neonatal outbreak in Copenhagen. This cluster contrasted with numerous small clusters, including the remaining Danish isolates and isolates from the other countries that interspersed throughout the tree. Most isolates were Panton-Valentine leukocidin (PVL) negative (95%) and harboured SCCmec IVa. One genome was closed using Oxford Nanopore technology and Illumina MiSeq. It contained a plasmid of 19.769 bp including the blaZ gene. A similar plasmid was found in 78% of all isolates.

DISCUSSION

t304/ST6 is a successful emerging clone and the fact that isolates from five countries are interspersed throughout the MST indicates a common origin. This clone is commonly described in the Middle East and its emergence in Europe coincides with influx of refugees from the Syrian Civil War.

Assessment of VITEK® MS IVD database V3.0 for identification of Nocardia spp. using two culture media and comparing direct smear and protein extraction procedures

We assessed the performance of the VITEK® MS IVD V3.0 matrix-assisted laser desorption ionization - time of flight mass spectrometry (MALDI-ToF MS) V3.0 database for the identification of Nocardia spp. as compared with targeted DNA sequencing. A collection of 222 DNA sequence-defined Nocardia spp. strains encompassing 18 different species present or not in the database was tested. Bromocresol purple agar (BCP) and Columbia agar +5% sheep's blood (COS) culture media were used together with two different preparation steps: direct smear and a "3 attempts" procedure that covered (1) spotting of an extract, (2) new spotting of the same extract, and (3) spotting of a new extract. The direct smear protocol yielded low correct identification rates (≤ 15% for both media) whereas protein extraction yielded correct identification results (> 67% regardless of the media used.). The use of 2 additional attempts using repeat or new extracts increased correct identification rates to 87% and 91% for BCP and COS, respectively. When using the 3 attempts procedure, the best identification results, independent of media types, were obtained for N. farcinica and N. cyriacigeorgica (100%). Identification attempts 2 and 3 allowed to increase the number of correct identifications (BCP, +20%; COS, +13%). The enhancement in performance during attempts 2 and 3 was remarkable for N. abscessus (81% for both media) and low prevalence species (BCP, 70%; COS, 85%). Up to 3.4% and 2.4% of the strains belonging to species present in the database were misidentified with BCP and COS media, respectively. In 1.9% of the cases for BCP and 1.4% for COS, these misidentifications concerned a species belonging to the same phylogenetic complex. Concerning strains that are not claimed in the V3.0 database, N. puris and N. goodfellowi generated "No identification" results and 100% of the strains belonging to N. arthritidis, N.cerradoensis, and N. altamirensis yielded a misidentification within the same phylogenetic complex. Vitek® MS IVD V3.0 is an accurate and useful tool for identification of Nocardia spp.

P09.08 Increased incidence of intracranial meningiomas in patients with acromegaly

BACKGROUND

An increased incidence of various neoplasms has been described in patients with acromegaly and there is evidence to suggest that growth factors are risk factors for the development of meningiomas. We aimed to study if patients with acromegaly are more at risk for developing intracranial meningiomas

MATERIAL AND METHODS

We conducted an observational study on 221 consecutive acromegalic patients recruited between January 1, 2000 and December 31, 2015, and 357 consecutive patients with a non-somatotropic pituitary adenoma recruited between March 1, 2015 and December 31, 2016 in our institution. Patients underwent a gadolinium-enhanced 3D T1 brain MRI to look for meningiomas. The proportion of meningiomas was compared between the two groups and the standardized incidence ratio (SIR) was computed from the incidence rates of meningiomas observed in the population of acromegalic patients and compared to that of the general population given by the local registry of central nervous system tumors.

RESULTS

Patients with acromegaly had a significant risk for developing intracranial meningiomas as compared to patients without acromegaly (7.7% vs. 2.2%, p = .005, OR = 3.45 [1.46; 8.15]). There was a significant increased incidence of intracranial meningiomas in patients with acromegaly (SIR = 126 [25; 367]) as compared to the general population.

CONCLUSION

Our study provides the first evidence that patients with acromegaly are more at risk for developing intracranial meningiomas.

Colistin-containing cement spacer for treatment of experimental carbapenemase-producing Klebsiella pneumoniae prosthetic joint infection

Carbapenemase-producing Enterobacteriaceae (CPE) are emerging multidrug-resistant bacteria responsible for invasive infections, including prosthetic joint infections (PJIs). Local administration of colistin may provide bactericidal concentrations in situ. This study evaluated the efficacy of a colistin-impregnated cement spacer, alone and in combination with systemic antibiotics, in a rabbit model of CPE-PJI. Elution of 3 MIU of colistimethate sodium (CMS) in 40 g of poly(methyl methacrylate) cement was studied in vitro. In vivo, 5 × 10⁸ CFU of KPC-producing Klebsiella pneumoniae (colistin and meropenem MICs of 1 mg/L and 4 mg/L, respectively) were injected close to a prosthetic knee. Surgical debridement and prosthesis removal were performed 7 days later, and rabbits were assigned to six treatment groups (11-13 rabbits each): drug-free spacer; colistin-loaded spacer; colistin intramuscular (i.m.); colistin i.m. + colistin spacer; colistin i.m. + meropenem subcutaneous (s.c.); and colistin i.m. + meropenem s.c. + colistin spacer. Systemic treatment was administered at doses targeting pharmacokinetics in humans, and rabbits were euthanised 7 days later to evaluate bacterial counts in infected bones. In vitro, CMS elution was low (<0.1% at 24 h) but reached a local concentration of ≥20 mg/L (>20 × MIC). In vivo, combinations of local and systemic colistin, with or without meropenem, were the only regimens superior to the control group (P ≤ 0.05) in terms of viable bacterial counts and the proportion of rabbits with sterile bone, with no emergence of colistin-resistant strains. Colistin-loaded cement spacer in combination with systemic antibiotics were the most effective regimens in this CPE-PJI model.

Clinical impact of vancomycin heteroresistance in staphylococcal strains involved in neonatal sepsis: Discussion of a case report

Heteroresistance to vancomycin (HRV) represents a decreased susceptibility to vancomycin and is frequently observed in multidrug-resistant coagulase-negative staphylococci. The clinical significance of such heteroresistance is controversial, but several failures of vancomycin therapy have been related to HRV, especially in the neonatal population. Here we report the case of a preterm neonate, born at 26 weeks of gestation, who developed sepsis due to a multidrug-resistant HRV Staphylococcuscapitis isolate. Bacteremia persisted despite adequate vancomycin serum concentration and catheter removal. The patient finally recovered after replacing vancomycin by linezolid. Through this case report, we would like to alert clinicians of the potential clinical impact of HRV and to discuss the lack of therapeutic alternatives in neonates.

Staphylococcus capitis and NRCS-A clone: the story of an unrecognized pathogen in neonatal intensive care units

BACKGROUND

In neonatal intensive care units (NICUs), nosocomial late-onset sepsis (LOS), mostly due to coagulase negative staphylococci, constitute a major cause of death or impairment. Staphylococcus capitis, usually considered as a poorly virulent species, has been reported as a cause of LOS.

OBJECTIVES

To review data regarding S. capitis neonatal LOS and the features of isolates involved.

SOURCES

PubMed was searched up to August 2018 to retrieve studies on the topic; the keywords used were 'S. capitis', 'neonate', 'neonatal ICU', 'bloodstream infection' and 'late onset sepsis'.

CONTENT

Published data highlight the worldwide endemicity of a single S. capitis clone, named NRCS-A, specifically involved in LOS. NRCS-A harbours a multidrug resistance profile (including resistance to the usual first-line antibiotics used in NICUs). It is also able to adapt under vancomycin selective pressure that could confer an advantage for its implantation and dissemination in NICUs where this selective pressure is high. Moreover, a severe morbidity has been observed in NRCS-A-related LOS. The NICU environment, and especially incubators, constitute reservoirs of NRCS-A from which it could diffuse inside the setting. Finally, the virulome and resistome of S. capitis NRCS-A contain many genes potentially implicated in its specific epidemiology and pathophysiology, including the gene nsr that may be involved in its fitness and implantation in neonatal gut flora.

IMPLICATIONS

S. capitis must be considered as a true pathogen in neonates. The decreased susceptibility to vancomycin may be involved in failure of vancomycin therapy. Further studies are needed to better manage its diffusion inside each NICU but also worldwide.

Radiofrequency ablation of stage IA non-small cell lung cancer in patients ineligible for surgery: results of a prospective multicenter phase II trial

Background

A prospective multicenter phase II trial to evaluate the survival outcomes of percutaneous radiofrequency ablation (RFA) for patients with stage IA non-small cell lung cancer (NSCLC), ineligible for surgery.

Methods

Patients with a biopsy-proven stage IA NSCLC, staging established by a positron emission tomography-computed tomography (PET-CT), were eligible. The primary objective was to evaluate the local control of RFA at 1-year. Secondary objectives were 1- and 3-year overall survival (OS), 3-year local control, lung function (prior to and 3 months after RFA) and quality of life (prior to and 1 month after RFA).

Results

Of the 42 patients (mean age 71.7 y) that were enrolled at six French cancer centers, 32 were eligible and assessable. Twenty-seven patients did not recur at 1 year corresponding to a local control rate of 84.38% (95% CI, [67.21–95.72]). The local control rate at 3 years was 81.25% (95% CI, [54.35–95.95]). The OS rate was 91.67% (95% CI, [77.53–98.25]) at 1 year and 58.33% (95% CI, [40.76–74.49]) at 3 years. The forced expiratory volume was stable in most patients apart from two, in whom we observed a 10% decrease. There was no significant change in the global health status or in the quality of life following RFA.

Conclusion

RFA is an efficient treatment for medically inoperable stage IA NSCLC patients. RFA is well tolerated, does not adversely affect pulmonary function and the 3-year OS rate is comparable to that of stereotactic body radiotherapy, in similar patients.

Trial registration

ClinicalTrials.gov Identifier NCT01841060 registered in November 2008.

Microbiologic epidemiology depending on time to occurrence of prosthetic joint infection: a prospective cohort study

OBJECTIVES

The high microbiologic diversity encountered in prosthetic joint infection (PJI) makes the choice of empirical antimicrobial therapies challenging, especially in cases of implant retention or one-stage exchange. Despite the risk of dysbiosis and toxicity, the combination of vancomycin with a broad-spectrum β-lactam is currently recommended in all cases, even if Gram-negative bacilli (GNB) might be less represented in late PJI. In this context, this study aimed to describe the microbiologic epidemiology of PJI according to the chronology of infection.

METHODS

This prospective cohort study (2011-2016) evaluated the microbiologic aetiology of 567 PJI according to time of occurrence from prosthesis implantation-early (<3 months), delayed (3-12 months) and late (>12 months)-as well as mechanism of acquisition.

RESULTS

Initial microbiologic documentation (n = 511; 90.1%) disclosed 164 (28.9%) Staphylococcus aureus (including 26 (16.1%) methicillin-resistant S. aureus), 162 (28.6%) coagulase-negative staphylococci (including 81 (59.1%) methicillin-resistant coagulase-negative staphylococci), 80 (14.1%) Enterobacteriaceae, 74 (13.1%) streptococci and 60 (10.6%) Cutibacterium acnes. Considering nonhaematogenous late PJI (n = 182), Enterobacteriaceae (n = 7; 3.8%) were less represented than in the first year after implantation (n = 56; 17.2%; p <0.001), without difference regarding nonfermenting GNB (4.6% and 2.7%, respectively). The prevalence of anaerobes (n = 40; 21.9%; including 32 (80.0%) C. acnes) was higher in late PJI (p <0.001). Consequently, a broad-spectrum β-lactam might be useful in 12 patients (6.6%) with late PJI only compared to 66 patients (20.3%) with early/delayed PJI (p <0.001).

CONCLUSIONS

Considering the minority amount of GNB in late postoperative PJI, the empirical use of a broad-spectrum β-lactam should be reconsidered, especially when a two-stage exchange is planned.

CT-texture analysis of subsolid nodules for differentiating invasive from in-situ and minimally invasive lung adenocarcinoma subtypes

PURPOSE

The purpose of this study was to evaluate the usefulness of computed tomography-texture analysis (CTTA) in differentiating between in-situ and minimally-invasive from invasive adenocarcinomas in subsolid lung nodules (SSLNs).

MATERIAL AND METHODS

Two radiologists retrospectively reviewed 49 SSLNs in 44 patients. There were 27 men and 17 women with a mean age of 63±7 (SD) years (range: 47-78years). For each SSLN, type (pure ground-glass or part-solid) was assessed by consensus and CTTA was conducted independently by each observer using a filtration-histogram technique. Different filters were used before histogram quantification: no filtration, fine, medium and coarse, followed by histogram quantification using mean intensity, standard deviation (SD), entropy, mean positive pixels (MPP), skewness and kurtosis.

RESULTS

We analyzed 13 pure ground-glass and 36 part-solid nodules corresponding to 16 adenocarcinomas in-situ (AIS), 5 minimally invasive adenocarcinomas (MIA) and 28 invasive adenocarcinomas (IVA). At uni- and multivariate analysis CTTA allowed discriminating between IVAs and AIS/MIA (P<0.05 and P=0.025, respectively) with the following histogram parameters: skewness using fine textures and kurtosis using coarse filtration for pure ground-glass nodules, and SD without filtration for part-solid nodules.

CONCLUSION

CTTA has the potential to differentiate AIS and MIA from IVA among SSLNs. However, our results require further validation on a larger cohort.

[HPV vaccination in boys and men : update and recommendations]

High-risk oncogenic HPVs (HR-HPV) are associated in men with pre-cancerous anal dysplasia, oropharyngeal, anal and penile cancer. Anogenital warts are induced by low-risk HPVs. These manifestations are increasing among men, and especially in some high-risk groups as men who have sex with men (MSM). This review targets HPV-associated disease epidemiology as well as safety, immunogenicity, and efficacy level of HPV vaccine in men. Obstacle and cost-effectiveness analysis of HPV vaccination are discussed. Three HPV vaccines are currently available in Belgium with the 9-valent (" 9HPV " - 6/11/16/18/31/33/45/52/58) offering protection against most of HPVassociated diseases. The safe 9-valent vaccine is efficient to prevent genital warts, anal dysplasia and it decreases the recurrence of genital warts and high grade anal neoplasia in MSM with or without HIV infection. In Europe, the 9-valent vaccine could prevent in men more than 350,000 genital warts, 5,485 oropharyngeal cancers, 2,303 anal cancers et 852 grade 2/3 intraepithelial neoplasia as well as 1,113 penile cancers per year. In the Federation Wallonie-Bruxelles, the vaccine coverage reaches currently 30 % in girls and is very low in boys and men.The Superior Health Council of Belgium (CSS) recommends since 2017 the gender-neutral HPV vaccination for people up to 26 years old and to immunocompromised patients. The implementation of the CSS HPV vaccine program and its acceptability among boys and men are discussed on the basis of the most recent epidemiologic data and available costeffectiveness analysis. Ways to overcome barriers to gender-neutral HPV vaccination are suggested.

[Meningococcal B (4CMenB) vaccine : uptodate and recommendations]

Neisseria meningitidis is the cause of relatively rare invasive infections, but with very important morbi-mortality. Vaccines are already available for serogroups A, C, W, Y. A new vaccine against meningococcus B is on the Belgian market since March 2017. Serogroup B is the most prevalent in Western countries. The target populations are children and teenager, since it is at this age that peaks in the incidence of meningococcal disease are observed. The development of this vaccine has been made possible by a new process named " reverse vaccinology ", which uses the complete genome sequencing of the bacterium. Current studies focus on the immunogenicity of the vaccine, which is good for both children and teenager. However, there are still many unknowns with this vaccine such as the duration of protection and its impact on the pharyngeal carriage. Another difficulty lies in the extrapolation of the immunogenicity data among a population because this vaccine consists of protein antigens and we know that the expression and prevalence of these antigens may vary between different strains of meningococci. In England, where the vaccine has been included in the vaccination calendar, beneficial effects are demonstrated on the incidence of invasive meningococcal infections. The toxicity profile is also reassuring, only classic side effects have been observed, such as fever and local reactions. In 2017, the High Health Council issued a favorable opinion for individual protection, without recommending at this stage a collective vaccination in Belgium. After a review of the most recent data on this new vaccine, we will try to draw conclusions.

Tigecycline-based prolonged salvage therapy in patients presenting with complex bone and joint infection

OBJECTIVES

To assess the clinical experience of tigecycline-based salvage therapy in patients presenting with Bone and Joint Infections (BJI).

PATIENTS AND METHODS

Multicenter retrospective cohort study in France and Turkey (2007-2014).

RESULTS

Thirty-six patients (age 58.2±17.8 years; 21 men) were included. The most frequently isolated bacteria were Enterobacteriaceae and staphylococci. Tigecycline (50mg BID, mainly in combination (69.4%), mean duration of 58 days) was indicated for multidrug resistance (90.6%) and/or previous antibiotic intolerance (36.1%), and/or as second- or third-line therapy (69.4%). Six patients (16.7%) experienced early treatment discontinuation for adverse event (4 severe vomiting, 1 pancreatitis, 1 asymptomatic lipase increase). Clinical success was observed in 23 of 30 assessable patients who completed the tigecycline therapy (mean follow-up: 54.1±57.7 weeks).

CONCLUSION

Prolonged tigecycline-based therapy could be an alternative in patients presenting with BJI requiring salvage therapy, especially if multidrug-resistant Enterobacteriaceae and/or staphylococci are involved.

Emergence and dissemination of a linezolid-resistant Staphylococcus capitis clone in Europe

Objectives

We investigated the epidemiological, clinical, microbiological and genetic characteristics of linezolid-resistant (LZR) Staphylococcus capitis isolates from French ICUs, and compared them with LZR S. capitis isolates from other European countries.

Methods

All LZR isolates were subjected to antimicrobial susceptibility testing (AST) and the presence of cfr and optrA genes as well as mutations in the 23S rRNA and ribosomal proteins were investigated using specific PCR with sequencing. The genetic relationship between isolates was investigated using PFGE and WGS. Epidemiological data concerning LZR S. capitis were collected retrospectively in French microbiology laboratories.

Results

Twenty-one LZR isolates were studied: 9 from France, 11 from Greece and 1 from Finland. All were resistant to methicillin and aminoglycosides. In addition, this unusual AST profile was identified in S. capitis isolates from seven French hospitals, and represented up to 12% of the S. capitis isolates in one centre. A G2576T mutation in 23S rRNA was identified in all isolates; cfr and optrA genes were absent. All isolates belonged to the same clone on the basis of their PFGE profiles, whatever their geographical origin. WGS found at most 212 SNPs between core genomes of the LZR isolates.

Conclusions

We identified and characterized an LZR S. capitis clone disseminated in three European countries, harbouring the same multiple resistance and a G2576T mutation in the 23S rRNA. The possible unrecognized wider distribution of this clone, belonging to a species classically regarded as a low-virulence skin colonizer, is of major concern not least because of the increasing use of oxazolidinones.

[Allergic bronchopulmonary aspergillosis: Evaluation of a maintenance therapy with nebulized Ambisome®]

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) affects 3-13% of patients with asthma. Its natural history includes possibly life-threatening exacerbations and evolution towards fixed obstructive ventilatory disorders or even irreversible lung fibrosis lesions. ABPA prognosis is directly associated with exacerbation control and the main objective of the treatment is to decrease their frequency and duration. Recommendations regarding dosage and duration of treatment are not very precise. The currently used combination of itraconazole and corticosteroid therapy has many limitations. The interests of a therapeutic strategy using nebulized liposomal amphotericin B (LAmB) are to heighten antifungal lung tissue concentration, to circumvent drug interactions and decrease the potential toxicity of systemic antifungal treatments. Finally, this association leads to improved eradication of Aspergillus, thereby limiting the risk of side effects and the emergence of treatment-resistant Aspergillus strains.

METHODS

This is a phase II, multicentre, randomized, single blind, controlled therapeutic study, with the objective of comparing the potential benefit on exacerbation control of a maintenance therapy by LAmB nebulization. The main objective of the study is to compare the incidence of severe clinical exacerbations in ABPA treatment, between a maintenance treatment strategy with nebulized LAmB and a conventional strategy without antifungal maintenance therapy.

EXPECTED RESULTS

The results will guide practitioners in the management of ABPA treatments and help to define the place of aerosols of LAmB on "evidence base medicine" criteria.

Vancomycin-intermediate Staphylococcus aureus isolates are attenuated for virulence when compared with susceptible progenitors

OBJECTIVES

Vancomycin-intermediate Staphylococcus aureus (VISA) is associated with genetic changes that may also impact upon pathogenicity. In the current study, we compared the virulence of clinical VISA strains with their isogenic vancomycin-susceptible progenitors (VSSA).

METHODS

Production of the critical virulence protein, α toxin, was assessed using Western blot analysis and was correlated to agr activity using a bioluminescent agr-reporter. Cytotoxicity and intracellular persistence were compared ex vivo for VSSA and VISA within non-professional phagocytes (NPP). Virulence and host immune responses were further explored in vivo using a murine model of bacteraemia.

RESULTS

VISA isolates produced up to 20-fold less α toxin compared with VSSA, and this was corroborated by either loss of agr activity due to agr mutation, or altered agr activity in the absence of mutation. VISA were less cytotoxic towards NPP and were associated with enhanced intracellular persistence, suggesting that NPP may act as a reservoir for VISA. Infection with VSSA strains produced higher mortality in a murine bacteraemia model (≥90% 7-day mortality) compared with infection with VISA isolates (20% to 50%, p <0.001). Mice infected with VISA produced a dampened immune response (4.6-fold reduction in interleukin-6, p <0.001) and persistent organ bacterial growth was observed for VISA strains out to 7 days.

CONCLUSIONS

These findings highlight the remarkable adaptability of S. aureus, whereby, in addition to having reduced antibiotic susceptibility, VISA alter the expression of pathogenic factors to circumvent the host immune response to favour persistent infection over acute virulence.

Vancomycin treatment is a risk factor for vancomycin-nonsusceptible Staphylococcus capitis sepsis in preterm neonates

OBJECTIVES

Multidrug-resistant, vancomycin-nonsusceptible Staphylococcus capitis is an emerging cause worldwide of late-onset sepsis (LOS) in preterm neonates. The pathophysiology and risk factors for S. capitis-related LOS are poorly understood, but we hypothesized that S. capitis LOS follows translocation from the gut microbiota rather than catheter invasion. The objective of this study was to investigate the risk factors of S. capitis LOS and gut colonization.

METHODS

We conducted a prospective single-centre cohort study of patients hospitalized in a tertiary-care unit (Lyon, France) from June 2011 to January 2012. S. capitis gut colonization was determined weekly from stool cultures. The determinants of gut colonization and LOS were established by multivariate Cox proportional hazards models.

RESULTS

Eighty-three (36.2%) of 229 patients had S. capitis-positive stool culture, and 28 (12.2%) developed S. capitis LOS during hospitalization. Independent risk factors for S. capitis LOS included prior administration of vancomycin independent of a previous LOS episode (hazard ratio 6.44, 95% confidence interval 2.15-19.3, p 0.001) and low birth weight (hazard ratio 0.72 per 100 g increase, 95% confidence interval 0.55-0.95, p 0.02). The prior administration of vancomycin was also an independent risk factor for S. capitis colonization (hazard ratio 3.45, 95% confidence interval 2.07-5.76, p <0.001), particularly in the first week of life and in noncolonized neonates.

CONCLUSIONS

Neonates treated with vancomycin are at a higher risk of LOS caused by vancomycin-nonsusceptible S. capitis. The use of vancomycin in neonates must urgently be optimized to limit the selection of vancomycin-nonsusceptible strains, for which alternative antibiotics are lacking.

[MRI of the pulmonary parenchyma: Towards clinical applicability?]

Lung parenchyma has long been considered out of the scope of magnetic resonance imaging (MRI) clinical applicability. However, technological advances have emerged to soluce the technical difficulties and thus, applications in clinical practice have become realistic. Nevertheless, various approaches have been proposed and there is a need to synthetize the most recent literature data in order to envision a rationale to build lung MR protocols for clinical use. In addition, these technological innovations may modify the usual paradigms of lung MRI, which are still not consensual. Thus, lung MR protocols appear to be heterogeneous across expert centers in the current context. In this literature review, we ought to describe a rationale on the need to get an alternative to ionizing imaging modalities, in particular in the follow-up of patients with chronic lung diseases. We will describe the most recent technical advances regarding both morphological and functional MRI. Finally, we will conclude on the clinical applicability of MRI of the pulmonary parenchyma, as a routine or research tool.

In vitro activity of ceftobiprole on 440 Staphylococcus aureus strains isolated from bronchopulmonary infections

OBJECTIVE

We assessed the in vitro activity of ceftobiprole on 440 Staphylococcus aureus clinical strains isolated from bronchopulmonary infections (2010-2014).

METHODS

S. aureus isolates were characterized for methicillin resistance, PVL status, and clonal complex. All isolates were tested for minimal inhibitory concentrations (MIC) determination by broth microdilution method for ceftobiprole, ceftaroline fosamil, and comparator antibiotics (linezolid, tigecycline, vancomycin, and daptomycin).

RESULTS

A total of 325 (74%) strains were methicillin-susceptible S. aureus (MSSA) and 115 (26%) were methicillin-resistant S. aureus (MRSA); 105 (24%) S. aureus strains were PVL-positive, including 35.2% (37/105) MRSA and 64.8% (68/105) MSSA. Ceftobiprole was highly active against S. aureus with MIC₉₀ of 1 mg/L, MICs ranging between 0.12 and 4mg/L (only one resistant strain, MIC of 4 mg/L). MIC₅₀ and MIC₉₀ were twice lower in MSSA than MRSA. Moreover, PVL⁺ MRSA were slightly more susceptible to ceftobiprole (MIC₅₀ of 0.5 mg/L and MIC₉₀ of 1 mg/L) than PVL^- MRSA (MIC₅₀ and MIC₉₀ of 1 mg/L). The ceftobiprole-resistant strain was also resistant to ceftaroline fosamil and presented the D239L mutation in PBP2A. The comparator antibiotics were equally active on the strains tested, with MIC₉₀ of 0.5 mg/L for ceftaroline fosamil, tigecycline, and daptomycin; 1 mg/L for vancomycin; and 2 mg/L for linezolid.

CONCLUSIONS

Our results suggest that ceftobiprole is highly active against S. aureus and is an effective alternative to vancomycin or linezolid in the management of staphylococcal pneumonia. However, close monitoring of isolates should be maintained to prevent resistant strain diffusion.

[Cutaneous lesions during hot-tub hypersensitivity pneumonitis: Pseudomonas folliculitis ?]

BACKGROUND

Interstitial lung disease, cutaneous rash and elevated serum angiotensin converting enzyme (ACE) may suggest diagnoses other than sarcoidosis.

PATIENTS AND METHODS

A 58-year-old man had presented dyspnoea for 2 years with increased angiotensin-converting enzyme, as well as an interstitial syndrome and micronodules. The possibility of sarcoidosis was raised. Systemic corticosteroids resulted in improvement of the dyspnoea although it recurred on dose reduction. We noted fluctuating eczematous macules of the limbs with a histology of aspecific folliculitis. The identification of Mycobacterium avium complex (MAC) in the bronchoalveolar wash prompted us to initiate antimycobacterial therapy, but this was to no avail. Review of the CT-scan and questioning of the patient (daily use of a Jacuzzi for 7 years) resulted in diagnosis of hypersensitivity pneumonitis due to MAC. The cutaneous lesions were taken to indicate "hot tub folliculitis". Discontinuation of hot-tub use and a short course of oral corticosteroids resulted in healing within 4 months, with no recurrence at 2 years.

DISCUSSION

HTL is a form of hypersensitivity pneumonitis due to the presence of MAC in the water of Jacuzzis. This condition regresses spontaneously without treatment on discontinuation of Jacuzzi use. Hot-tub folliculitis due to Pseudomonas aeruginosa (PA) presents as macules and papules on covered skin areas (swimsuit) within 48hours of bathing and often declines within 2 weeks.

CONCLUSION

Our case is original as regards the concomitant lung and cutaneous involvement associated with Jacuzzi use, with an immunoallergic mechanism for the MAC and probably an infectious mechanism for the PA.

MRSA infections among patients in the emergency department: a European multicentre study

BACKGROUND

MRSA is a therapeutic concern worldwide, and a major agent of community-acquired skin and soft tissue infections (CA-SSTIs). While the US epidemiology of MRSA in CA-SSTIs is well described and reports the high prevalence of the USA300 clone, data on the European situation are lacking.

OBJECTIVES

To determine the prevalence and clonal characteristics of MRSA in CA-SSTIs in seven European emergency departments.

PATIENTS AND METHODS

From April to June 2015, patients presenting to the tertiary hospital emergency department with a Staphylococcus aureus CA-SSTI were prospectively enrolled. S. aureus isolates were characterized by antimicrobial susceptibility testing, detection of Panton-Valentine leucocidin encoding genes and spa-typing, MLST and/or DNA microarray.

RESULTS

Two-hundred and five cases of S. aureus-associated CA-SSTIs were included, comprising folliculitis, furuncles, abscesses, paronychia, impetigo, carbuncles and cellulitis. Of the 205 cases, we report an MRSA prevalence rate of 15.1%, with a north (0%) to south (29%) increasing gradient. Fifty-one isolates were Panton-Valentine leucocidin-positive (24.9%), whether MSSA or MRSA, with a heterogeneous distribution between countries. Clonal distribution of MSSA and MRSA showed high diversity, with no predominant circulating clone and no archetypical USA300 CA-MRSA clone.

CONCLUSIONS

This original prospective multicentre study highlights stark differences in European MRSA epidemiology compared with the USA, and that the USA300 CA-MRSA clone is not predominant among community-infected patients in Europe.

Late-onset sepsis due to Staphylococcus capitis 'neonatalis' in low-birthweight infants: a new entity?

During hospitalization, sepsis occurs in one of every five very-low-birthweight infants. The emergence of Staphylococcus capitis (SC)-related sepsis in preterm infants was observed recently. This study aimed to evaluate the clinical severity of SC-related sepsis in preterm infants. Of the 105 infants who presented with sepsis related to coagulase-negative staphylococci, 74 were SC. Severe morbidity was more common in the SC group (55.4%) than in the non-SC coagulase-negative staphylococci group (32.0%) (P=0.03). Multi-variate analysis identified SC-related sepsis as an independent risk factor for severe morbidity.