Impact of variants of SARS-CoV-2 on obstetrical and neonatal outcomes

BACKGROUND

SARS-CoV-2 can lead to several types of complications during pregnancy. Variant surges are associated with different severities of disease. Few studies have compared the clinical consequences of specific variants on obstetrical and neonatal outcomes. Our goal was to evaluate and compare disease severity in pregnant women and obstetrical or neonatal complications between variants of SARS-CoV-2 that have circulated in France over a two-year period (2020-2022).

METHOD

This retrospective cohort study included all pregnant women with a confirmed SARS-CoV-2 infection (positive naso-pharyngeal RT-PCR test) from March 12, 2020 to January 31, 2022, in three tertiary maternal referral obstetric units in the Paris metropolitan area, France. We collected clinical and laboratory data for mothers and newborns from patients' medical records. Variant identification was either available following sequencing or extrapolated from epidemiological data.

RESULTS

There were 234/501 (47%) Wild Type (WT), 127/501 (25%) Alpha, 98/501 (20%) Delta, and 42/501 (8%) Omicron. No significative difference was found regarding two composite adverse outcomes. There were significantly more hospitalizations for severe pneumopathy in Delta variant than WT, Alpha and Omicron respectively (63% vs 26%, 35% and 6%, p<0.001), more frequent oxygen administration (23% vs 12%, 10% and 5%, p = 0,001) and more symptomatic patients at the time of testing with Delta and WT (75% and 71%) versus Alpha and Omicron variants (55% and 66% respectively, p<0.01). Stillbirth tended to be associated with variants (p = 0.06): WT 1/231 (<1%) vs 4/126 (3%), 3/94 (3%), and 1/35 (3%) in Alpha, Delta and Omicron cases respectively. No other difference was found.

CONCLUSION

Although the Delta variant was associated with more severe disease in pregnant women, we found no difference regarding neonatal and obstetrical outcomes. Neonatal and obstetrical specific severity may be due to mechanisms other than maternal ventilatory and general infection.

Impact des variants du SARS-CORONAVIRUS-2 sur les issues obstétricales et néonatales

Introduction

Le SARS-CORONAVIRUS-2 est un virus à ARN en évolution génétique constante. L’accumulation de mutations génétiques est à l’origine de l’émergence de variants dont la prolifération et la diffusion ont entraîné les différentes vagues de la pandémie.

Ces mutations confèrent au virus des facteurs de virulence, qui peuvent avoir des impacts cliniques significatifs.

Les conséquences spécifiques de l’infection au cours de la grossesse ont déjà été mises en évidence, avec pour principale complication, la prématurité.

Des données très récentes évoquent une plus grande sévérité de l’infection au variant DELTA.

Cette étude a pour but de comparer les issues obstétricales lors des infections à CORONAVIRUS-19 en cours de grossesse, en fonction du variant concerné.

Méthodes

Il s’agit d’une étude observationnelle, rétrospective, bicentrique, basée sur l’analyse des dossiers médicaux des patientes ayant contracté la COVID au cours de leur grossesse avec un diagnostic par PCR, depuis février 2020. Les critères de jugement concernaient la sévérité de l’infection maternelle, les issues obstétricales (prématurité, survenue d’un retard de croissance intra-utérin ou d’une prééclampsie, hospitalisation, modalités d’accouchement) et les issues néonatales (poids de naissance, adaptation à la vie extra-utérine, complications néonatales).

Le recueil des données est toujours en cours.

Résultats

Il s’agit de résultats préliminaires concernant les patientes symptomatiques ou dépistées au cours d’une mise en travail spontanée prématurée ou au diagnostic d’une mort fœtale in utero.

Des variants ont été identifiés dans 30 % des cas et sont ainsi répartis : Delta (5 %), UK (20 %), South African et Belgian (3 %). Les souches virales restantes sont soit de type sauvage (wild type), soit indéterminé avec une identification parfois toujours en cours.

Le terme de naissance est de 35 SA dans le groupe Delta vs 37 SA dans le groupe UK.

Le groupe Delta comporte 58 % de patientes sévères contre 24 % dans le groupe UK.

Conclusion

L’infection à SARS-CORONAVIRUS-2 semble être de gravité différente en fonction du variant concerné avec une sévérité de la maladie et un taux de prématurité plus importants en cas de variant Delta, malgré le faible nombre de patientes porteuses analysées à ce jour.

Distribution of edin in Staphylococcus aureus isolated from diabetic foot ulcers

Staphylococcus aureus is both a common colonizer of human skin and the most frequently isolated pathogen in diabetes foot infections (DFIs). The spread of DFI to soft tissue and bony structures is a major causal factor for lower-limb amputation. It is therefore of great importance to differentiate colonizing from infecting strains of S. aureus. Epidermal cell differentiation inhibitors known as EDIN and EDIN-like factors, a group of toxins targeting RhoA master regulator of the actin cytoskeleton, may confer virulence properties on S. aureus. In this study, for the first time, analysis of S. aureus strains, recovered in DFIs at an initial stage and during the follow-up, showed that 71.4% of edin-positive strains were associated with moderate-to-severe infections (grades 3 and 4 of the IDSA/IWGDF classification) compared with 28.6% of edin-positive strains associated with low-grade infections. Most of these strains were edin-B positive (86.7%) and belonged to CC25/28-MSSA (n = 10). One edin-B-positive ST152-MSSA strain was negative for the two highly prevalent predictive markers of infecting strains (lukDE and hlgv). Collectively, this points towards the edin-B encoding gene as a bonafide subsidiary predictive risk marker of DFI.

High prevalence of edin-C encoding RhoA-targeting toxin in clinical isolates of Staphylococcus aureus

Staphylococcus aureus, a major causative agent of human infection, produces a large array of virulence factors, including various toxins. Among them, the host RhoA GTPase ADP-ribosylating EDIN toxins are considered as potential virulence factors. Using the polymerase chain reaction (PCR) assay, we analyzed the virulence profile of 256 S. aureus isolates from various clinical sites of infections. We developed specific primers to detect the three isoforms of edin-encoding genes. We found a prevalence of 14% (36 bacteria) of edin-encoding genes among these clinical isolates. Strikingly, we found that 90% of all edin-bearing S. aureus isolates carried the type-C allele. Both the spa types and the profile of virulence factors of these edin-positive isolates are highly variable. Notably, we show for the first time that edin-C-positive isolates were more frequently recovered from deep-seated infections than other types of infections. Our present work, thus, strongly suggests that the presence of edin-C is a risk factor of S. aureus dissemination in tissues and, thus, represents a predictive marker for a pejorative evolution of staphylococcal infections.

Antibiotic misuse: a prospective clinical audit in a French university hospital

The aim of the study presented here was to prospectively audit antibiotic prescriptions given to patients attending L'Archet Hospital in Nice, France, with details of the initial medical examination included in the audit procedure. A total of 122 antibiotic treatments were evaluated, i.e. 31% of all antibiotic therapies initiated in the eight participating departments over the 9-week study period. Forty-two (34%) treatments were found to be unnecessary due to misdiagnosis, and 36 (30%) other treatments were inappropriate. Misdiagnosis, due to the misinterpretation or lack of clinical, microbiological and/or imaging data is thus a major cause of antibiotic misuse. Improvement in the diagnostic process should become part of antibiotic policy.

Adrenal tuberculosis after a pheochromocytoma: a misleading tumoral presentation

Adrenal gland involvement could account for 6% of active tuberculosis. The diagnosis of this extrapulmonary form of tuberculosis is difficult, especially when presenting as unilateral adrenal tumor. This report describes an unusual case of adrenal tuberculosis presenting as a tumor occurring shortly after surgical removal of an adrenal pheochromocytoma located in the opposite gland, in a 63-year-old woman with a previous history of breast cancer. At initial presentation, the patient suffered from symptomatic paroxysmal hypertension. A pheochromocytoma in the left adrenal was diagnosed and resected. One year later, while physical examination and biological parameters were unremarkable, an enhanced adrenal computed tomography (CT) scan showed a right adrenal mass mimicking the CT features of the resected pheochromocytoma. A peripheral tissular rim delineating a central hypodensity characterized this tumor. Magnetic resonance imaging (MRI) showed the same findings on gadolinium-enhanced T1-weighted slices, while the mass was not seen on T2-weighted images. No tumoral signal loss was observed on out of phase images when using the in phase-out of phase T1-weighted sequence. Because of the tumoral evolution and the uncertainty of the nature of that lesion, the patient underwent a second adrenalectomy. Definitive diagnosis was provided by culture of tissue sample, which resulted in the identification of Mycobacterium tuberculosis. In an era of tuberculosis resurgence, this unusual case underscores the necessity of keeping in mind adrenal tuberculosis as a possible differential diagnosis in adrenal tumors of uncertainty nature. It stresses the importance of culture of biopsy tumor, whenever feasible, to avoid unnecessary operations. In the near future, interferon-gamma assay could be a valuable means to recognize extrapulmonary forms of tuberculosis.

Frequency of Escherichia coli strains producing the cytotoxic necrotizing factor (CNF1) in nosocomial urinary tract infections

The presence of cytotoxic necrotizing factor 1 (CNF1), together with various associated virulence factors (alpha-haemolysin, P-, S- and A-fimbriae), was screened in 175 uropathogenic Escherichia coli strains isolated from hospitalized adult patients. The cnf1 gene was detected in 30% of the selected strains independently of the severity of the clinical urinary infection. A significant association between CNF1, haemolytic activity and the products of the pap/sfa genes was found. However, CNF1 appeared not to play a major role in nosocomial E. coli urinary tract infections.

Increased Escherichia coli phagocytosis in neutrophils that have transmigrated across a cultured intestinal epithelium

The functionality of polymorphonuclear leukocytes (PMNs) once they migrate into the digestive lumen is still ill defined. More specifically, phagocytic function and bactericidal action of PMNs after transepithelial migration have not received much attention. The aim of the present study is to compare PMN behavior before and after transepithelial migration, in particular (i) phagocytosis and bactericidal activity; (ii) expression of surface molecules, particularly those involved in phagocytosis; and (iii) apoptosis. Cultured human intestinal epithelial T84 cell monolayers were used. The effect of transepithelial migration on phagocytosis was evaluated by immunofluorescence and electron microscopy and by flow cytometric assessment of the engulfment of a strain of Escherichia coli transfected with the green fluorescent protein. Superoxide production by PMNs was investigated by luminol-mediated chemiluminescence. Expression of various surface molecules on PMNs was evaluated by flow cytometry, while PMN apoptosis was assayed by morphologic changes and DNA fragmentation. E. coli phagocytosis by the PMNs was markedly increased after transepithelial migration without modification of superoxide production. CD11b/CD18 and CD47 expression was increased upon PMN transmigration, whereas CD16 expression was decreased and CD29, CD46, CD49e, CD49f, CD55, CD59, CD61, CD95 levels remained unchanged. Apoptosis in transmigrated PMNs was slightly advanced and was observed after 12 h compared to 16 h for nontransmigrated PMNs. In conclusion, the phagocytic capacity of the PMNs is augmented after transepithelial migration, with a dramatic increase in the level of CD11b/CD18 and preservation of the superoxide production. These results suggest a higher bactericidal activity of the PMNs once they have translocated into the digestive lumen.

Deamidation of RhoA glutamine 63 by the Escherichia coli CNF1 toxin requires a short sequence of the GTPase switch 2 domain

CNF1, a toxin produced by pathogenic Escherichia coli strains, deamidates the RhoA GTP-binding protein glutamine 63 and impairs RhoGAP-mediated GTP hydrolysis resulting in RhoA permanent activation. Using peptides derived from the RhoA sequence, we found that DTAGQEDYDRL (corresponding to RhoA 59-69 residues) was the minimum RhoA-derived peptide which could be deamidated in vitro by the CNF1 catalytic domain (CNF1-Cter). Site-directed mutagenesis outside the RhoA 59-69 sequence had no influence on glutamine 63 deamidation by CNF1-Cter. RhoA proteins with substitutions L57G, D65G, Y66G, or R70G were not affected in their ability to be deamidated by CNF1-Cter, whereas this was abolished by the R68G substitution. Arginine 68 is part of the DYDRL motif that is strictly conserved in Rho, Rac, and Cdc42 but not in other small GTP-binding proteins consistent with the observation that only Rho, Rac, and Cdc42 can be modified by CNF1.