The first mitotic division: a perilous bridge connecting the zygote and the early embryo.

Human embryos are very frequently affected by maternally inherited aneuploidies, which in the vast majority of cases determine developmental failure at pre- or post-implantation stages. However, recent evidence, generated by the alliance between diverse technologies now routinely employed in the IVF laboratory, has revealed a broader, more complex scenario. Aberrant patterns occurring at the cellular or molecular level can impact at multiple stages of the trajectory of development to blastocyst. In this context, fertilization is an extremely delicate phase, as it marks the transition between gametic and embryonic life. Centrosomes, essential for mitosis, are assembled ex novo from components of both parents. Very large and initially distant nuclei (the pronuclei) are brought together and positioned centrally. The overall cell arrangement is converted from being asymmetric to symmetric. The maternal and paternal chromosome sets, initially separate and scattered within their respective pronuclei, become clustered where the pronuclei juxtapose, to facilitate their assembly in the mitotic spindle. The meiotic spindle is replaced by a segregation machinery that may form as a transient or persistent dual mitotic spindle. Maternal proteins assist the decay of maternal mRNAs to allow the translation of newly synthesized zygotic transcripts. The diversity and complexity of these events, regulated in a precise temporal order and occurring in narrow time windows, make fertilization a highly error-prone process. As a consequence, at the first mitotic division, cellular or genomic integrity may be lost, with fatal consequences for embryonic development.

Delayed blastocyst development is influenced by the level of progesterone on the day of trigger.

PURPOSE: To evaluate the association between progesterone (P) level on the day of trigger and time to blastulation in IVF cycles. METHODS: This was a retrospective cohort study with autologous IVF cycles performed at our Institution from January 2019 to December 2021. A total of 1109 IVF cycles were included. The primary outcome was to compare time to blastulation in terms of percentage of expanded (grade 3) blastocysts on day 5 according to progesterone level at trigger. RESULTS: A total of 3517 blastocysts were analyzed. After dividing progesterone level in quartiles (Q1, P < 0.50 ng/ml; Q2 0.50 ng/ml ≤ P ≤ 0.78 ng/ml; Q3, 0.79 ng/ml ≤ P ≤ 1.15 ng/ml; Q4, P > 1.15 ng/ml), we observed a delay in blastocyst development according to the increasing level of progesterone at trigger (analysis by rank, P-value = 0.01). After adjusting for confounding factors at the multivariate analysis, the percentage of day 5 blastocysts was reduced for Q3 (- 13.8%, 95% CI from - 20.5 to - 7.0%, p < 0.001) and Q4 (- 7.7%, 95% CI from - 15.5 to 0.0%, p = 0.05) compared to Q1 (reference). CONCLUSIONS: Progesterone levels on day of trigger correlate to the percentage of expanded (grade 3) blastocysts on day 5 and a delayed blastocyst development day 5 is expected for high progesterone levels.

Clinical and laboratory key performance indicators in IVF: A consensus between the Italian Society of Fertility and Sterility and Reproductive Medicine (SIFES-MR) and the Italian Society of Embryology, Reproduction and Research (SIERR).

PURPOSE: Infertility is increasing worldwide, and many couples seek IVF. Clinical management and laboratory work are fundamental in the IVF journey. Therefore, the definition of reliable key performance indicators (KPIs) based on clinical and laboratory parameters, is essential for internal quality control (IQC). Laboratory performance indicators have been identified and a first attempt to also determine clinical ones has been recently published. However, more detailed indicators are required. METHODS: An Italian group of experts in Reproductive Medicine from both public and private clinics on behalf of SIFES-MR and SIERR was established to define IVF indicators to monitor clinical performance. RESULTS: The working group built a consensus on a list of KPIs, performance indicators (PIs) and recommendation indicators (RIs). When deemed necessary, the reference population was stratified by woman age, response to ovarian stimulation and adoption of preimplantation genetic testing for aneuploidies (PGT-A). Each indicator was scored with a value from 1 to 5 and a weighted average formula - considering all the suggested parameters-was defined. This formula generates a center performance score, indicating low, average, good, or excellent performance. CONCLUSION: This study is intended to provide KPIs, PIs and RIs that encompass several essential aspects of a modern IVF clinic, including quality control and constant monitoring of clinical and embryological features. These indicators could be used to assess the quality of each center with the aim of improving efficacy and efficiency in IVF.

Inter-centre reliability in embryo grading across several IVF clinics is limited: implications for embryo selection.

RESEARCH QUESTION: What is the intra- and inter-centre reliability in embryo grading performed according to the Istanbul Consensus across several IVF clinics? DESIGN: Forty Day 3 embryos and 40 blastocysts were photographed on three focal planes. Senior and junior embryologists from 65 clinics were invited to grade them according to the Istanbul Consensus (Study Phase I). All participants then attended interactive training where a panel of experts graded the same embryos (Study Phase II). Finally, a second set of pictures was sent to both embryologists and experts for a blinded evaluation (Study Phase III). Intra-centre reliability was reported for Study Phase I as Cohen's kappa between senior and junior embryologists; inter-centre reliability was instead calculated between senior/junior embryologists and experts in Study Phase I versus III to outline improvements after training (i.e. upgrade of Cohen's kappa category according to Landis and Koch). RESULTS: Thirty-six embryologists from 18 centres participated (28% participation rate). The intra-centre reliability was (i) substantial (0.63) for blastomere symmetry (range -0.02 to 1.0), (ii) substantial (0.72) for fragmentation (range 0.29-1.0), (iii) substantial (0.66) for blastocyst expansion (range 0.19-1.0), (iv) moderate (0.59) for inner cell mass quality (range 0.07-0.92), (v) moderate (0.56) for trophectoderm quality (range 0.01-0.97). The inter-centre reliability showed an overall improvement from Study Phase I to III, from fair (0.21-0.4) to moderate (0.41-0.6) for all parameters under analysis, except for blastomere fragmentation among senior embryologists, which was already moderate before training. CONCLUSIONS: Intra-centre reliability was generally moderate/substantial, while inter-centre reliability was just fair. The interactive training improved it to moderate, hence this workflow was deemed helpful. The establishment of external quality assessment services (e.g. UK NEQAS) and the avant-garde of artificial intelligence might further improve the reliability of this key practice for embryo selection.

Use of mineral oil in IVF culture systems: physico-chemical aspects, management, and safety.

PURPOSE: The study aims to summarize current knowledge on the use of oil in embryo culture systems, with a focus on proper management of different types of oil and possible impact on culture systems. METHODS: PubMed was used to search the MEDLINE database for peer-reviewed English-language original articles and reviews concerning the use of oil in embryo culture systems. Searches were performed by adopting "embryo," "culture media," "oil," and "contaminants" as main terms. The most relevant publications were assessed and discussed critically. RESULTS: Oils used in IVF are complex mixtures of straight-chain hydrocarbons, cyclic and aromatic hydrocarbons, and unsaturated hydrocarbons, whose precise composition influences their chemical and physical properties. Possible presence of contaminants suggests their storage at 4 °C in the dark to prevent peroxidation. Washing, generally performed by manufacturers prior to commercialization, may remove trace chemical contaminants. Oils reduce evaporation from culture media at rates depending on their chemical physical properties, culture system parameters, and incubator atmosphere. Contaminants - mainly metal ion and plastic components derived from refinement processes and storage - can pass to the aqueous phase of culture systems and affect embryo development. CONCLUSIONS: Oils are essential components of culture systems. Their original quality and composition, storage, handling, and use can affect embryo development with significant efficiency and safety implications.

When embryology meets genetics: the definition of developmentally incompetent preimplantation embryos (DIPE)-the consensus of two Italian scientific societies.

A clear definition of developmentally incompetent preimplantation embryo (DIPE) in literature is still missing, while several scientific societies are discussing this challenging topic. From both a clinical and scientific perspective, the identification of embryos unfit for reproductive purpose is crucial. This aim should be pursued in light of all diagnostic technologies for embryo evaluation, encompassing also genetic analyses, of recent implementation in IVF. The Italian context is characterized by an unusual scenario: embryos can be discarded only if not viable and cannot be used for research purposes either. Therefore, thousands of embryos, diagnosed as affected and/or aneuploid as resulting from preimplantation genetic testing (PGT) and clinically not utilizable, are cryopreserved and stored indefinitely, with important psychological, legal, and financial implications. With the aim of updating the definition of DIPE, also on the basis of the embryo genetic status, the Italian Society of Embryology, Reproduction and Research (SIERR) and the Italian Society of Human Genetic (SIGU) reviewed the literature on this topic, found a consensus, and produced a list of relevant criteria.

Type of protein supplement in cryopreservation solutions impacts on the degree of ultrastructural damage in frozen-thawed human oocytes.

Protein sources used as supplements of IVF culture media are known to have several implications for the function and stability of embryo culture environment. In fact, they i) transport biologically active molecules ii) chelate heavy metals, iii) regulate media pH, iii) scavenge reactive oxygen species (ROS) and iv) attenuate osmotic stress to which cells are exposed in sub-optimal culture conditions. Instead, their specific relevance to the formulation of cryopreservation solutions used for gamete and embryo cryopreservation remains uncertain. In the present work, we tested the hypothesis that different protein supplements present in cryopreservation solutions, serum or plasma protein solution (PPS), or different concentrations of the same supplement (serum), are associated with different types and/or magnitude of cryopreservation-derived cell damage. To this end, using cryopreservation solutions containing serum or PPS, donated supernumerary human mature oocytes were frozen-thawed by slow freezing and compared with fresh controls. Ultrastructural markers of oocyte quality were adopted as objective measure to assess possible damage from cryopreservation. The study results indicate that the adoption of serum minimises cell damage induced by cryopreservation. Indeed, typical hallmarks of cryodamage in human oocytes, i.e. loss of cortical granules, zona pellucida hardening and above all vacuolization, were largely reduced in oocytes cryopreserved with solutions containing serum, especially if used a higher concentration. This suggest that oocyte cryopreservation still has significant margins of improvement that may derive also from composition of cryopreservation media.

IUI and uterine lavage of in vivo-produced blastocysts for PGT purposes: is it a technically and ethically reasonable perspective? Is it actually needed?

A recent study by Munné et al. portrayed a protocol to retrieve in vivo produced blastocysts after IUI and uterine lavage for preimplantation genetic testing (PGT) purposes. The authors claimed this protocol might represent a reasonable future perspective for patients who do not want to undergo IVF, but still want to be informed about their embryos' genetic/chromosomal defects. Although the intent of making PGT available also to patients who cannot or do not need to undergo IVF is respectable, the value of this study is undermined by severe technical and ethical issues. Munné and colleagues' paper was discussed within the executive committee (i.e., president and vice-president of the society, director and vice-director of the scientific committee, secretariat, and counselors), the special interest group in reproductive genetics, the scientific committee, and the collegio dei probiviri of the Italian Society of Embryology, Reproduction and Research (SIERR). The points raised from this discussion are summarized in this opinion paper.

Controlled ovarian stimulation and IVF pregnancy in a trisomy X carrier with associated hypogonadotropic hypogonadism.

We describe successful controlled ovarian stimulation (COS) and the first known IVF pregnancy in a trisomy X carrier with associated hypogonadotropic hypogonadism (HH) linked to a chromosome 4 double mutation in the allele of the Gonadotropins Releasing Hormone receptor (GnRHr) gene. Previous administration of low dose of gonadotropins, as recommended in patients with HH, led to poor follicular recruitment. Since trisomy X is a risk factor for diminished ovarian reserve (DOR) and premature ovarian insufficiency (POI), higher doses of gonadotropins led to better ovarian response. The report readknowledges the importance of a correct genetic evaluation in a competent laboratory as a reliable base for treatment planning in this kind of patients.

Granulosa cell and oocyte mitochondrial abnormalities in a mouse model of fragile X primary ovarian insufficiency.

STUDY HYPOTHESIS: We hypothesized that the mitochondria of granulosa cells (GC) and/or oocytes might be abnormal in a mouse model of fragile X premutation (FXPM). STUDY FINDING: Mice heterozygous and homozygous for the FXPM have increased death (atresia) of large ovarian follicles, fewer corpora lutea with a gene dosage effect manifesting in decreased litter size(s). Furthermore, granulosa cells (GC) and oocytes of FXPM mice have decreased mitochondrial content, structurally abnormal mitochondria, and reduced expression of critical mitochondrial genes. Because this mouse allele produces the mutant Fragile X mental retardation 1 (Fmr1) transcript and reduced levels of wild-type (WT) Fmr1 protein (FMRP), but does not produce a Repeat Associated Non-ATG Translation (RAN)-translation product, our data lend support to the idea that Fmr1 mRNA with large numbers of CGG-repeats is intrinsically deleterious in the ovary. WHAT IS KNOWN ALREADY: Mitochondrial dysfunction has been detected in somatic cells of human and mouse FX PM carriers and mitochondria are essential for oogenesis and ovarian follicle development, FX-associated primary ovarian insufficiency (FXPOI) is seen in women with FXPM alleles. These alleles have 55-200 CGG repeats in the 5' UTR of an X-linked gene known as FMR1. The molecular basis of the pathology seen in this disorder is unclear but is thought to involve either some deleterious consequence of overexpression of RNA with long CGG-repeat tracts or of the generation of a repeat-associated non-AUG translation (RAN translation) product that is toxic. STUDY DESIGN, SAMPLES/MATERIALS, METHODS: Analysis of ovarian function in a knock-in FXPM mouse model carrying 130 CGG repeats was performed as follows on WT, PM/+, and PM/PM genotypes. Histomorphometric assessment of follicle and corpora lutea numbers in ovaries from 8-month-old mice was executed, along with litter size analysis. Mitochondrial DNA copy number was quantified in oocytes and GC using quantitative PCR, and cumulus granulosa mitochondrial content was measured by flow cytometric analysis after staining of cells with Mitotracker dye. Transmission electron micrographs were prepared of GC within small growing follicles and mitochondrial architecture was compared. Quantitative RT-PCR analysis of key genes involved in mitochondrial structure and recycling was performed. MAIN RESULTS AND THE ROLE OF CHANCE: A defect was found in follicle survival at the large antral stage in PM/+ and PM/PM mice. Litter size was significantly decreased in PM/PM mice, and corpora lutea were significantly reduced in mice of both mutant genotypes. Mitochondrial DNA copy number was significantly decreased in GC and metaphase II eggs in mutants. Flow cytometric analysis revealed that PM/+ and PM/PM animals lack the cumulus GC that harbor the greatest mitochondrial content as found in wild-type animals. Electron microscopic evaluation of GC of small growing follicles revealed mitochondrial structural abnormalities, including disorganized and vacuolar cristae. Finally, aberrant mitochondrial gene expression was detected. Mitofusin 2 (Mfn2) and Optic atrophy 1 (Opa1), genes involved in mitochondrial fusion and structure, respectively, were significantly decreased in whole ovaries of both mutant genotypes. Mitochondrial fission factor 1 (Mff1) was significantly decreased in PM/+ and PM/PM GC and eggs compared with wild-type controls. LIMITATIONS, REASONS FOR CAUTION: Data from the mouse model used for these studies should be viewed with some caution when considering parallels to the human FXPOI condition. WIDER IMPLICATIONS OF THE FINDINGS: Our data lend support to the idea that Fmr1 mRNA with large numbers of CGG-repeats is intrinsically deleterious in the ovary. FXPM disease states, including FXPOI, may share mitochondrial dysfunction as a common underlying mechanism. LARGE SCALE DATA: Not applicable. STUDY FUNDING AND COMPETING INTERESTS: Studies were supported by NIH R21 071873 (J.J./G.H), The Albert McKern Fund for Perinatal Research (J.J.), NIH Intramural Funds (K.U.), and a TUBITAK Research Fellowship Award (B.U.). No conflict(s) of interest or competing interest(s) are noted.

Hypogonadotropic hypogonadism in a trisomy X carrier: phenotype description and genotype correlation.

We report on a 31-year old female who presented at genetic counseling for a small uterus, secondary amenorrhea and sterility. Gonadotropic hormone levels were low, suggesting a Hypogonadotropic Hypogonadism (HH) condition. Cytogenetic analysis demonstrated the presence of Trisomy X associated to an interstitial deletion of chromosome 4q13.2, resulting in the complete loss of a copy of the GNRHR gene. As GNRHR is known to be responsible for an autosomal recessive form of HH, we checked the status of the undeleted allele and we found the Q106R substitution. In conclusion, the results of our cytogenetic and molecular analyses have allowed us to clarify the etiology of the patient's condition.

Training and competency assessment of Clinical Embryologists and licensing of the profession in European countries.

STUDY QUESTION: How is the acquisition and testing of theoretical and practical knowledge in Clinical Embryology and the licensing of ART laboratory personnel carried out in European countries? SUMMARY ANSWER: Twelve out of 31 European countries have established some kind of verification of laboratory competency and skills in ART: in 7 countries, this was related to licensing, but where organized education for Clinical Embryologists existed, there were vast differences in the way these processes were undertaken. WHAT IS KNOWN ALREADY: In 2015, a report by the ESHRE Embryology Certification Committee concluded that regardless of the large number of people working in IVF laboratories, Clinical Embryology was only recognized as an official profession in 3 out of 27 European national health systems. In most countries, Clinical Embryologists needed to be officially registered under an alternative profession and there were limited opportunities for organized education in this specialist field. Five years after this report, the ESHRE Working Group on Embryologist Training Analysis conducted a survey to collect detailed information about how Clinical Embryologists from different European countries are acquiring their theoretical knowledge and practical skills in ART, and how their level of education and competence in Clinical Embryology is verified. STUDY DESIGN SIZE DURATION: Two questionnaires about the possibilities for acquiring the education and training needed to work in ART and verification of this knowledge were prepared by the ESHRE Working Group on Embryologist Training Analysis. The first was sent in 2020 to a panel of invited lead European Embryologists who attended an Expert Meeting held in Rome, Italy. In order to have a more comprehensive and updated picture, in 2021 the same survey was also sent to the ESHRE Committee of National Representatives (CNRs). At the end of 2021, the second survey with specific questions, more focused on Clinical Embryologists' training and licencing, was sent to the CNRs who reported on verification of education in Clinical Embryology. PARTICIPANTS/MATERIALS SETTING METHODS: The first survey consisted of 17 questions. It was initially submitted to 14 lead Embryologists and then resubmitted to the 34 ESHRE CNRs. Representatives from 31 countries responded. A second survey with 23 questions was sent to the 12 ESHRE CNRs who reported an established national system of verification of education in Clinical Embryology, with specific questions focused on the training of Clinical Embryologists. All 12 CNRs responded. MAIN RESULTS AND THE ROLE OF CHANCE: Analysis showed that European national education programmes in Clinical Embryology could be split into 4 categories: non-existent (13 countries), recommended (5 countries), simple compulsory (9 countries), and complex compulsory (4 countries). A national document stating the minimum education requirements for staff to work in an IVF laboratory was reported by 19 respondents. The requirement to follow a prescribed theoretical and laboratory training programme in ART was compulsory in 9 and 10 countries, respectively. Some form of verification of laboratory skills, theoretical knowledge in ART, and continuing professional development was required in 12, 10, and 9 countries, respectively. A national trainee's logbook format was reported by seven respondents and a national tutorial system was available in six countries. Only seven countries had official licensing of ART laboratory staff. The title of Clinical Embryologist was not recognized in 13 countries and in 6 countries, it was used only by professional bodies, while in 12 countries the profession was at least cited in governmental regulations. The ESHRE Clinical Embryologist Certificate was officially recognized in eight countries. LIMITATIONS REASONS FOR CAUTION: The survey took place in two steps and the results were then combined to provide a representative picture for most of the European countries sampled. The vast majority, but not all, of the CNRs answered the request to participate in the survey. WIDER IMPLICATIONS OF THE FINDINGS: The professional recognition of Clinical Embryology within Europe is steadily evolving. However, it remains a concern that many countries continue to not recognize Clinical Embryology as a profession, with a vast difference in the reported organization of educational and training programmes and verification of skills. It is recommended that a training programme for Clinical Embryology and ART in Europe should be standardized and relevant issues should be addressed by competent authorities and European Union institutions. ESHRE is best placed to take a leading role in this educational process. STUDY FUNDING/COMPETING INTERESTS: The Working Group members who are the authors of this article did not receive payments for the completion of this study. The authors have no conflicts of interest to declare.

Risk factors for infections caused by carbapenem-resistant Enterobacterales: an international matched case-control-control study (EURECA).

Background: Data on risk factors for carbapenem-resistant Enterobacterales (CRE) with wider applicability are needed to inform preventive measures and efficient design of randomised trials. Methods: An international matched case-control-control study was performed in 50 hospitals with high CRE incidence from March 2016 to November 2018 to investigate different aspects of infections caused by CRE (NCT02709408). Cases were patients with complicated urinary tract infection (cUTI), complicated intraabdominal (cIAI), pneumonia or bacteraemia from other sources (BSI-OS) due to CRE; control groups were patients with infection caused by carbapenem-susceptible Enterobacterales (CSE), and by non-infected patients, respectively. Matching criteria included type of infection for CSE group, ward and duration of hospital admission. Conditional logistic regression was used to identify risk factors. Findings: Overall, 235 CRE case patients, 235 CSE controls and 705 non-infected controls were included. The CRE infections were cUTI (133, 56.7%), pneumonia (44, 18.7%), cIAI and BSI-OS (29, 12.3% each). Carbapenemase genes were found in 228 isolates: OXA-48/like, 112 (47.6%), KPC, 84 (35.7%), and metallo-ß-lactamases, 44 (18.7%); 13 produced two. The risk factors for CRE infection in both type of controls were (adjusted OR for CSE controls; 95% CI; p value) previous colonisation/infection by CRE (6.94; 2.74-15.53; <0.001), urinary catheter (1.78; 1.03-3.07; 0.038) and exposure to broad spectrum antibiotics, as categorical (2.20; 1.25-3.88; 0.006) and time-dependent (1.04 per day; 1.00-1.07; 0.014); chronic renal failure (2.81; 1.40-5.64; 0.004) and admission from home (0.44; 0.23-0.85; 0.014) were significant only for CSE controls. Subgroup analyses provided similar results. Interpretation: The main risk factors for CRE infections in hospitals with high incidence included previous colonization, urinary catheter and exposure to broad spectrum antibiotics. Funding: The study was funded by the Innovative Medicines Initiative Joint Undertaking (https://www.imi.europa.eu/) under Grant Agreement No. 115620 (COMBACTE-CARE).

Laparoscopic Oocyte Retrieval and Cryopreservation during Vaginoplasty for Treatment of Mayer-Rokitansky-Kuster-Hauser Syndrome.

In Mayer-Rokitansky-Kuster-Hauser Syndrome (MRKHS) patients who are scheduled for laparoscopic vaginoplasty and have a desire for biological motherhood, we propose that a concomitant laparoscopic oocyte retrieval for cryopreservation is performed. Oocyte retrieval is pursued at the beginning of the laparoscopy. Right and left 5 mm trocars are positioned, through which a 17 G ovum aspiration needle is used for puncture of the right and left ovaries, respectively. To facilitate exposure of the follicles, the ovaries are mobilized and held with laparoscopic forceps. When aspirating multiple follicles near each other, the needle tip is retained in the ovary to reduce the number of times that the ovarian cortex is transfixed and due to the inherent risk of bleeding. Subsequent steps are unchanged compared to the Davydov laparoscopic modified technique for vaginoplasty. Prior to surgery, controlled ovarian stimulation is performed with a gonadotropin hormone-releasing hormone (Gn-RH) antagonist protocol, and the concomitant procedure of oocyte retrieval and vaginoplasty is scheduled 36 h after the final follicular maturation trigger. Follicular fluid is collected in the same 10 mL sterile tubes used during transvaginal oocyte retrieval and transferred in a warming block (37 °C) to the assisted reproduction laboratory, where mature (metaphase II) oocytes are vitrified. In this case, a series of 23 women with MRKH, oocytes were successfully retrieved and cryopreserved in all patients; vaginoplasty was subsequently conducted without modifications, and the inpatient and outpatient postoperative care (day of urinary catheter removal, day of hospital discharge, dilator use, and comfort at follow-up) remained unaffected. One postoperative complication occurred in one patient (fever developing on day 5 post surgery and intraperitoneal fluid detection on transabdominal ultrasound) and resolved after conservative treatment. Rather than performing surgical vaginoplasty and delaying oocyte retrieval in MRKH patients, this approach combines both procedures in a single laparoscopy, thereby minimizing surgical invasiveness and anesthesiologic risks.

Myocarditis Related to COVID-19 and SARS-CoV-2 Vaccination.

The coronavirus disease of 2019 (COVID-19) has been a cause of significant morbidity and mortality worldwide. Among the short- and long-term consequences of COVID-19, myocarditis is a disease to be taken into consideration. Myocarditis, in general, is related to a poor prognosis. However, the epidemiology and prognosis of myocarditis related to COVID-19 are currently unknown. While vaccination against COVID-19 is of great benefit at a public health level, the risk of myocarditis should be considered in the context of the global benefits of vaccination. In this narrative review, we will summarize the etiopathogenic bases, the epidemiology, the clinical manifestations, the course, diagnosis, prognosis, and the treatment of myocarditis related to SARS-CoV-2, as well as myocarditis secondary to mRNA vaccines.

Effectiveness of Fosfomycin for the Treatment of Multidrug-Resistant Escherichia coli Bacteremic Urinary Tract Infections: A Randomized Clinical Trial.

Importance: The consumption of broad-spectrum drugs has increased as a consequence of the spread of multidrug-resistant (MDR) Escherichia coli. Finding alternatives for these infections is critical, for which some neglected drugs may be an option. Objective: To determine whether fosfomycin is noninferior to ceftriaxone or meropenem in the targeted treatment of bacteremic urinary tract infections (bUTIs) due to MDR E coli. Design, Setting, and Participants: This multicenter, randomized, pragmatic, open clinical trial was conducted at 22 Spanish hospitals from June 2014 to December 2018. Eligible participants were adult patients with bacteremic urinary tract infections due to MDR E coli; 161 of 1578 screened patients were randomized and followed up for 60 days. Data were analyzed in May 2021. Interventions: Patients were randomized 1 to 1 to receive intravenous fosfomycin disodium at 4 g every 6 hours (70 participants) or a comparator (ceftriaxone or meropenem if resistant; 73 participants) with the option to switch to oral fosfomycin trometamol for the fosfomycin group or an active oral drug or parenteral ertapenem for the comparator group after 4 days. Main Outcomes and Measures: The primary outcome was clinical and microbiological cure (CMC) 5 to 7 days after finalization of treatment; a noninferiority margin of 7% was considered. Results: Among 143 patients in the modified intention-to-treat population (median [IQR] age, 72 [62-81] years; 73 [51.0%] women), 48 of 70 patients (68.6%) treated with fosfomycin and 57 of 73 patients (78.1%) treated with comparators reached CMC (risk difference, -9.4 percentage points; 1-sided 95% CI, -21.5 to ∞ percentage points; P = .10). While clinical or microbiological failure occurred among 10 patients (14.3%) treated with fosfomycin and 14 patients (19.7%) treated with comparators (risk difference, -5.4 percentage points; 1-sided 95% CI, -∞ to 4.9; percentage points; P = .19), an increased rate of adverse event-related discontinuations occurred with fosfomycin vs comparators (6 discontinuations [8.5%] vs 0 discontinuations; P = .006). In an exploratory analysis among a subset of 38 patients who underwent rectal colonization studies, patients treated with fosfomycin acquired a new ceftriaxone-resistant or meropenem-resistant gram-negative bacteria at a decreased rate compared with patients treated with comparators (0 of 21 patients vs 4 of 17 patients [23.5%]; 1-sided P = .01). Conclusions and Relevance: This study found that fosfomycin did not demonstrate noninferiority to comparators as targeted treatment of bUTI from MDR E coli; this was due to an increased rate of adverse event-related discontinuations. This finding suggests that fosfomycin may be considered for selected patients with these infections. Trial Registration: ClinicalTrials.gov Identifier: NCT02142751.