La place du dosage de l'interleukine 6 chez les patients hospitalisés dans une unité COVID (en dehors du milieu de la réanimation)

Introduction

Le développement d'une forme grave de COVID-19 pourrait être causé par la survenue d'un syndrome de libération de cytokines pro-inflammatoires. L‘interleukine 6 (IL-6) est une cytokine qui joue un rôle clé dans la mobilisation et la coordination de la réponse immunitaire pour contenir l'infection par le SARS-CoV-2. L'objectif de notre étude est d'évaluer les niveaux d'IL-6 chez les patients atteints de COVID-19 admis en dehors du milieu de réanimation et leur corrélation avec la forme clinique.

Matériels et méthodes

Il s'agit d'une étude rétrospective descriptive analytique mené à l'unité COVID-19 durant 12 mois [2020-2021]. Tous les patients ayant eu un dosage de l'IL-6 à l'admission.

Résultats

Ils s'agissaient de 81 patients, 53 hommes et 28 femmes (sex-ratio H/F=1,9), âgés en moyenne de 58,4 ans [20-93 ans]. Le délai moyen d'hospitalisation était de 8 jours [2-21 jours]. La forme clinique à l'admission était sévère dans 91 % et modérée dans 9 % des cas. La symptomatologie était dominée par l'asthénie (79 %), la toux (74,1 %), la dyspnée (63 %), l'arthromyalgie (59,3 %) et la fièvre (58 %). Au moins une comorbidité était présente chez 88 % des patients. Les plus fréquentes étaient l'hypertension artérielle (40 %), le diabète (30,9 %), les pathologies cardio-vasculaires (13,6 %) et les maladies respiratoires chroniques (7,5 %). une TDM thoracique réalisée chez 80 patients avait objectivé des lésions évocatrices avec une étendue entre 50 et 75 % (34,6 %), 25 et 50 % (28,4 %) et 10 et 25 % (18,5 %). La valeur moyenne des globules blancs est de 7122 ± 3564 éléments/mm³, celle de CRP de 104,6 ± 59,6 mg/l, de la ferritinémie de 412 pg/l [188 -643pg/L] et des D-dimères de 743 µg/l (481 – 1729µg/l). Le taux de l'IL6 était augmenté chez tous les patients avec une valeur moyenne de 42pg/ml +/- 54 pg/ml [2 et 580 pg/ml]. Le taux d'IL-6 était significativement plus élevée dans les formes sévères que dans les formes modérées (p=0,01). La valeur moyenne de l'IL-6 était de 20,2pg/ml et de 58,6 pg/ml respectivement dans la forme modérée et la forme sévère. L'évolution était favorable dans 92,6 % des cas. Six patients (7,4 %) sont décédés. Le modèle multivarié de Cox a montré que le taux d'IL-6 pouvait être utilisé comme facteur indépendant pour prédire la gravité de la COVID-19 (p <0,001).

Conclusion

Les taux sériques d'IL-6 sont significativement plus élevés dans les formes sévères que dans les formes modérées de COVID-19 et peuvent être considérés comme critère de gravité. Son taux sanguin est un bon marqueur de l'évolution.

Aucun lien d'intérêt

Description of an original integron encompassing blaVIM-2, qnrVC1 and genes encoding bacterial group II intron proteins in Pseudomonas aeruginosa

OBJECTIVES

A burn unit of a hospital in Tunis underwent an endemic situation caused by imipenem-resistant Pseudomonas aeruginosa. For nine non-repetitive isolates of a clonal VIM-2-producing strain, the blaVIM-2 genetic background was characterized and the associated qnrVC1 gene molecularly analysed.

METHODS

The imipenem resistance mechanism was investigated by phenotypic and molecular tests, and resistance transfer was studied by conjugation and transformation experiments. The integron's structure was characterized by sequencing, and qnrVC1 expression was explored after cloning experiments.

RESULTS

The nine VIM-2-producing strains were collected from eight patients and one environmental sample. All transfer assays failed, suggesting a chromosomal location of blaVIM-2. This latter was found to be part of a class 1 integron of ∼7500 bp, which also contains blaOXA-2, aadA1 and two copies of the aadB, arr-6 and qnrVC1 genes. qnrVC1 exhibited higher homology with the chromosomally encoded qnr genes of Vibrionaceae than with plasmid-mediated qnr genes of Enterobacteriaceae. The qnrVC1 gene cassette possesses a promoter allowing its expression, and it conferred decreased fluoroquinolone susceptibility to Escherichia coli. Additionally, on the same integron, genes encoding an uncommon group IIC-attC intron were detected.

CONCLUSIONS

A VIM-2-producing P. aeruginosa outbreak led us to characterize an integron harbouring a qnrVC1 cassette and a new group IIC-attC intron. This is the first known description of a qnr determinant in a P. aeruginosa strain. Its presence conferred a low level of resistance to quinolones in E. coli, which might favour the emergence of highly resistant mutants.

[Hypertrophic osteoarthropathy associated with pulmonary tuberculosis]

Hypertrophic osteoarthropathy is a syndrome frequently described in intrathoracic diseases, especially malignant ones. The association with lung tuberculosis is rarely reported. The authors describe the case of a 35-year-old patient, a smoker, hospitalised for lung cavitation associated with hypertrophic osteoarthropathy. The assessment of the aetiology was negative and the patient underwent lung surgery. The histopathological examination concluded as to chronic pulmonary tuberculosis. This report aims at alerting physicians about the possibility of hypertrophic osteoarthropathy in non malignant diseases, especially pulmonary tuberculosis which is still endemic in our country.

Clonality of Providencia stuartii isolates involved in outbreak that occurred in a burn unit

In order to investigate an outbreak of multidrug-resistant Providencia stuartii that occurred in a burn unit, we analyzed by pulsed-field gel electrophoresis (PFGE) all isolates of P. stuartii collected during 4 months of 2005 from patients and from a tracheal aspirator. Seventeen clinical isolates of P. stuartii, extended-spectrum beta-lactamase (ESBL) producing, were collected from 17 patients. All these isolates were nosocomially acquired. Three other isolates were collected from the aspirator probe, the aspirator reservoir and from the aspirator tube. Three different antibiotypes were identified without correlation with the genotype. Two PFGE types were obtained (types A and B) with predominance of one (type A) that was observed for 15 isolates. P. stuartii isolates collected from different components of the aspirator (probe, reservoir and tube) yielded PFGE type A. This study suggests the bi-clonality of the outbreak and that transmission of epidemic P. stuartii isolates was through a common source. The aspirator probe, contaminated from aspirator that functioned as a reservoir of bacteria, seems to be the route of transmission of P. stuartii. Furthermore, this study shows the utility of PFGE in typing for the purpose of understanding the epidemiological behaviour of P. stuartii and as a basis for the development of rational control strategies.

Optimum parameters of TLD100 powder used for radiotherapy beams calibration check

External audit of the absorbed dose determination from radiotherapy machines is performed using Lithium fluoride (LiF) TLD-100. Optimal parameters needed to obtain highly accurate dosage from LiF powder was investigated, including the setup of the Harshaw 4000 reader. A linear correspondence between the thermoluminescent signal and the mass of the powder was observed, demonstrating that the dose can be evaluated with small samples of powder. The reproducibility of the thermoluminescence dosimeter (TLD) readings obtained with up to 10 samples from 1 capsule containing 160 mg of powder was around 1.5% (1 standard deviation [SD]). The time required for the manual evaluation of TLDs can be improved by 3 readings without loss of accuracy. Better reproducibility is achieved if the capsules are evaluated 7 days after irradiation using a nitrogen flow of 300 cc/min.