New Thiazolidine-4-One Derivatives as SARS-CoV-2 Main Protease Inhibitors.

It has been more than four years since the first report of SARS-CoV-2, and humankind has experienced a pandemic with an unprecedented impact. Moreover, the new variants have made the situation even worse. Among viral enzymes, the SARS-CoV-2 main protease (Mpro) has been deemed a promising drug target vs. COVID-19. Indeed, Mpro is a pivotal enzyme for viral replication, and it is highly conserved within coronaviruses. It showed a high extent of conservation of the protease residues essential to the enzymatic activity, emphasizing its potential as a drug target to develop wide-spectrum antiviral agents effective not only vs. SARS-CoV-2 variants but also against other coronaviruses. Even though the FDA-approved drug nirmatrelvir, a Mpro inhibitor, has boosted the antiviral therapy for the treatment of COVID-19, the drug shows several drawbacks that hinder its clinical application. Herein, we report the synthesis of new thiazolidine-4-one derivatives endowed with inhibitory potencies in the micromolar range against SARS-CoV-2 Mpro. In silico studies shed light on the key structural requirements responsible for binding to highly conserved enzymatic residues, showing that the thiazolidinone core acts as a mimetic of the Gln amino acid of the natural substrate and the central role of the nitro-substituted aromatic portion in establishing π-π stacking interactions with the catalytic His-41 residue.

Association between COVID-19 vaccination and stroke: a nationwide case-control study in Qatar.

OBJECTIVE: This study investigated the association between Coronavirus Disease 2019 mRNA vaccination and stroke in Qatar. METHODS: Between December 1, 2020, and April 11, 2023, a matched case-control study was conducted to investigate the association between 3036 acute stroke cases and 3036 controls drawn from the entire population of Qatar. RESULTS: The adjusted odds ratio (aOR) for vaccination among cases compared to controls was 0.87 (95% CI: 0.75-1.00). The aOR was 0.74 (95% CI: 0.45-1.23) for a single vaccine dose, 0.87 (95% CI: 0.73-1.04) for primary-series vaccination (two doses), and 0.91 (95% CI: 0.66-1.25) for booster vaccination (three or more doses). The aOR was 0.87 (95% CI: 0.72-1.04) for BNT162b2 and 0.86 (95% CI: 0.67-1.11) for mRNA-1273. Subgroup analyses, considering different durations since vaccination, also demonstrated no association. Subgroup analyses based on nationality, age, number of coexisting conditions, or prior infection status yielded similar results. Subgroup analysis, stratified by stroke type, suggested an association between vaccination and cerebral venous sinus thrombosis (aOR of 2.50 [95% CI: 0.97-6.44]), but it did not reach statistical significance. CONCLUSION: There was no evidence of an increased risk of stroke following vaccination, both in the short term and in the long term, extending beyond a year after receiving the vaccine.

Population genomic analyses reveal high diversity, recombination and nosocomial transmission among Candida glabrata (Nakaseomyces glabrata) isolates causing invasive infections.

Candida glabrata is a commensal yeast of the gastrointestinal tract and skin of humans. However, it causes opportunistic infections in immunocompromised patients, and is the second most common Candida pathogen causing bloodstream infections. Although there are many studies on the epidemiology of C. glabrata infections, the fine- and large-scale geographical nature of C. glabrata remain incompletely understood. Here we investigated both the fine- and large-scale population structure of C. glabrata through genome sequencing of 80 clinical isolates obtained from six tertiary hospitals in Qatar and by comparing with global collections. Our fine-scale analyses revealed high genetic diversity within the Qatari population of C. glabrata and identified signatures of recombination, inbreeding and clonal expansion within and between hospitals, including evidence for nosocomial transmission among coronavirus disease 2019 (COVID-19) patients. In addition to signatures of recombination at the population level, both MATa and MATα alleles were detected in most hospitals, indicating the potential for sexual reproduction in clinical environments. Comparisons with global samples showed that the Qatari C. glabrata population was very similar to those from other parts of the world, consistent with the significant role of recent anthropogenic activities in shaping its population structure. Genome-wide association studies identified both known and novel genomic variants associated with reduced susceptibilities to fluconazole, 5-flucytosine and echinocandins. Together, our genomic analyses revealed the diversity, transmission patterns and antifungal drug resistance mechanisms of C. glabrata in Qatar as well as the relationships between Qatari isolates and those from other parts of the world.

Switch to oral antibiotics in Gram-negative bacteraemia: a randomized, open-label, clinical trial.

OBJECTIVES: To evaluate the safety and efficacy of switching from intravenous (IV) to oral antimicrobial therapy in patients with Enterobacterales bacteraemia, after completion of 3-5 days of microbiologically active IV therapy. METHODS: A multicentre, open-label, randomized trial of adults with monomicrobial Enterobacterales bacteraemia caused by a strain susceptible to ≥1 oral beta-lactam, quinolone, or trimethoprim/sulfamethoxazole. Inclusion criteria included completion of 3-5 days of microbiologically active IV therapy, being afebrile and haemodynamically stable for ≥48 hours, and absence of an uncontrolled source of infection. Pregnancy, endocarditis, and neurological infections were exclusion criteria. Randomization, stratified by urinary source of bacteraemia, was to continue IV (IV Group) or to switch to oral therapy (Oral Group). Agents and duration of therapy were determined by the treating physicians. The primary endpoint was treatment failure, defined as death, need for additional antimicrobial therapy, microbiological relapse, or infection-related re-admission within 90 days. Non-inferiority threshold was set at 10% in the 95% CI for the difference in the proportion with treatment failure between the Oral and IV Groups in the modified intention-to-treat population. The protocol was registered at ClinicalTrials.gov (NCT04146922). RESULTS: In the modified intention-to-treat population, treatment failure occurred in 21 of 82 (25.6%) in the IV Group, and 18 of 83 (21.7%) in the Oral Group (risk difference -3.7%, 95% CI -16.6% to 9.2%). The proportions of subjects with any adverse events (AE), serious AE, or AE leading to treatment discontinuation were comparable. DISCUSSION: In patients with Enterobacterales bacteraemia, oral switch, after initial IV antimicrobial therapy, clinical stability, and source control, is non-inferior to continuing IV therapy.

Genomic Epidemiology of Carbapenem-Resistant Klebsiella in Qatar: Emergence and Dissemination of Hypervirulent Klebsiella pneumoniae Sequence Type 383 Strains.

The emergence of carbapenem-resistant, hypervirulent Klebsiella pneumoniae is a new threat to health care. We studied the molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae isolates in Qatar using whole-genome sequence data. We also characterized the prevalence and genetic basis of hypervirulent phenotypes and established the virulence potential using a Galleria mellonella model. Of 100 Klebsiella isolates studied, NDM and OXA-48 were the most common carbapenemases. Core genome single-nucleotide polymorphism (SNP) analysis indicated the presence of diverse sequence types and clonal lineages; isolates belonging to Klebsiella quasipneumoniae subsp. quasipneumoniae sequence type 196 (ST196) and ST1416 may be disseminated among several health care centers. Ten K. pneumoniae isolates carried rmpA and/or truncated rmpA2, and 2 isolates belonged to KL2, indicating low prevalence of classical hypervirulent isolates. Isolates carrying both carbapenem resistance and hypervirulence genes were confined mainly to ST231 and ST383 isolates. One ST383 isolate was further investigated by MinION sequencing, and the assembled genome indicated that blaNDM was located on an IncHI1B-type plasmid (pFQ61_ST383_NDM-5) which coharbored several virulence factors, including the regulator of the mucoid phenotype (rmpA), the regulator of mucoid phenotype 2 (rmpA2), and aerobactin (iucABCD and iutA), likely resulting from recombination events. Comparative genomics indicated that this hybrid plasmid may be present in two additional Qatari ST383 isolates. Carbapenem-resistant, hypervirulent K. pneumoniae ST383 isolates pose an emerging threat to global health due to their simultaneous hypervirulence and multidrug resistance.

Molecular characterization of Candida auris outbreak isolates in Qatar from patients with COVID-19 reveals the emergence of isolates resistant to three classes of antifungal drugs.

OBJECTIVES: During the COVID-19 pandemic in Qatar, many patients who were severely ill were colonized and infected by Candida auris, an invasive multidrug-resistant yeast pathogen that spreads through nosocomial transmission within healthcare facilities. Here, we investigated the molecular epidemiology of these C. auris isolates and the mechanisms associated with antifungal drug resistance. METHODS: Whole genomes of 76 clinical C. auris isolates, including 65 from patients with COVID-19 collected from March 2020 to June 2021, from nine major hospitals were sequenced on Illumina NextSeq. Single nucleotide polymorphisms were used to determine their epidemiological patterns and mechanisms for antifungal resistance. The data were compared with those published prior to the COVID-19 pandemic from 2018 to 2020 in Qatar. RESULTS: Genomic analysis revealed low genetic variability among the isolates from patients with and without COVID-19, confirming a clonal outbreak and ongoing dissemination of C. auris among various healthcare facilities. Based on antifungal susceptibility profiles, more than 70% (22/28) of isolates were resistant to both fluconazole and amphotericin B. Variant analysis revealed the presence of multi-antifungal resistant isolates with prominent amino acid substitutions: Y132F in ERG11 and V704L in CDR1 linked to reduced azole susceptibility and the emergence of echinocandin resistance samples bearing mutations in FKS1 in comparison with pre-COVID-19 pandemic samples. One sample (CAS109) was resistant to three classes of antifungal drugs with a unique premature stop codon in ERG3 and novel mutations in CDR2, which may be associated with elevated amphotericin B and azole resistance. DISCUSSION: Candida auris isolates from patients with COVID-19 and from most patient samples without COVID-19 in Qatar were highly clonal. The data demonstrated the emergence of multidrug-resistant strains that carry novel mutations linked to enhanced resistance to azoles, echinocandins, and amphotericin B. Understanding the epidemiology and drug resistance will inform the infection control strategy and drug therapy.

Persistence of spike-specific immune responses in BNT162b2-vaccinated donors and generation of rapid ex-vivo T cells expansion protocol for adoptive immunotherapy: A pilot study.

Introduction: The BNT162b2 mRNA-based vaccine has shown high efficacy in preventing COVID-19 infection but there are limited data on the types and persistence of the humoral and T cell responses to such a vaccine. Methods: Here, we dissect the vaccine-induced humoral and cellular responses in a cohort of six healthy recipients of two doses of this vaccine. Results and discussion: Overall, there was heterogeneity in the spike-specific humoral and cellular responses among vaccinated individuals. Interestingly, we demonstrated that anti-spike antibody levels detected by a novel simple automated assay (Jess) were strongly correlated (r=0.863, P<0.0001) with neutralizing activity; thus, providing a potential surrogate for neutralizing cell-based assays. The spike-specific T cell response was measured with a newly modified T-spot assay in which the high-homology peptide-sequences cross-reactive with other coronaviruses were removed. This response was induced in 4/6 participants after the first dose, and all six participants after the second dose, and remained detectable in 4/6 participants five months post-vaccination. We have also shown for the first time, that BNT162b2 vaccine enhanced T cell responses also against known human common viruses. In addition, we demonstrated the efficacy of a rapid ex-vivo T cell expansion protocol for spike-specific T cell expansion to be potentially used for adoptive-cell therapy in severe COVID-19, immunocompromised individuals, and other high-risk groups. There was a 9 to 13.7-fold increase in the number of expanded T cells with a significant increase of anti-spike specific response showing higher frequencies of both activation and cytotoxic markers. Interestingly, effector memory T cells were dominant in all four participants' CD8+ expanded memory T cells; CD4+ T cells were dominated by effector memory in 2/4 participants and by central memory in the remaining two participants. Moreover, we found that high frequencies of CD4+ terminally differentiated memory T cells were associated with a greater reduction of spike-specific activated CD4+ T cells. Finally, we showed that participants who had a CD4+ central memory T cell dominance expressed a high CD69 activation marker in the CD4+ activated T cells.

Case Report: Central retinal artery occlusion following sildenafil intake.

Purpose: To report a case of central retinal artery occlusion associated with sildenafil intake and briefly discuss its causative pathogenesis. Methods: A 50-year-old man with no premorbidities presented with symptoms of sudden severe visual field constriction in the left eye (LE). Best-corrected visual acuity in the LE was 20/25. Fundus examination and fluorescein angiography of the LE were suggestive of central retinal artery occlusion (CRAO) with cilioretinal artery sparing. Further investigation revealed that 100 mg of sildenafil had been taken for the first time three hours before the onset of symptoms. Results: The patient was treated promptly with intravenous acetazolamide, sublingual isosorbide dinitrate and ocular massage, but without visual recovery. No other associated systemic or local risk factors were found, and the case was classified as a potential complication of sildenafil. Conclusion: Although no direct link could be established, the aim of this report is to highlight the incidence and to consider this issue when evaluating any case of central retinal artery occlusion.

Favipiravir for the treatment of coronavirus disease 2019 pneumonia; a propensity score-matched cohort study.

We retrospectively investigated the clinical outcomes of favipiravir in patients with COVID-19 pneumonia. Patients who between 23 May 2020 and 18 July 2020 received ≥ 24 h of favipiravir were assigned to the favipiravir group, while those who did not formed the non-favipiravir group. The primary outcome was 28-day clinical improvement, defined as two-category improvement from baseline on an 8-point ordinal scale. Propensity scores (PS) for favipiravir therapy were used for 1:1 matching. The unmatched cohort included 1493 patients, of which 51.7% were in the favipiravir group, and 48.3% were not receiving supplemental oxygen at baseline. Significant baseline differences between the two unmatched groups existed, but not between the PS-matched groups (N = 774). After PS-matching, there were no significant differences between the two groups in the proportion with 28-day clinical improvement (93.3% versus 92.8%, P 0.780), or 28-day all-cause mortality (2.1% versus 3.1%, P 0.360). Favipiravir was associated with more viral clearance by day 28 (79.8% versus 64.1%, P < 0.001). Adverse events were common in both groups, but the 93.9% were Grades 1-3. Favipiravir therapy for COVID-19 pneumonia is well tolerated but is not associated with an increased likelihood of clinical improvement or reduced all-cause mortality by 28 days.

Intrauterine infection and postpartum bacteremia due to Streptococcus gallolyticus subsp gallolyticus: An emerging concern.

Streptococcus gallolyticus is a gram-positive coccus belonging to the family Streptococcus bovis/Streptococcus equinus complex (SBSEC). Most cases of SBSEC bacteremia are reported in elderly males with underlying hepatobiliary disease and associated with infective endocarditis (IE) or colonic malignancy. The gastrointestinal tract is the most common portal of entry, followed by the urinary tract and hepatobiliary tree. We present 5 cases of intrapartum bacteremia caused by S. gallolyticus subsp gallolyticus reported from the labor unit of our hospital from 2019 to 2021. There was histopathological or microbiological evidence of chorioamnionitis in each case. All the mothers were below the age of 35 years, and none of them had underlying hepatobiliary or colonic disease. All maternal antenatal screenings for group B streptococci (GBS) were negative. All the isolates were susceptible to penicillins, ceftriaxone, carbapenems, and vancomycin. Three of them were treated with ceftriaxone and two with aminopenicillins. Duration of treatment varied from 8 days to 14 days. None of the babies were low birth weight or pre-term. All but one baby had clinical sepsis requiring neonatal intensive care unit (NICU) stay, with one having evidence of meningitis and three respiratory distress syndromes (RDS). None of the babies had S. gallolyticus bacteremia. All mothers and babies made a complete recovery without any complications. These cases suggest that S. gallolyticus subsp gallolyticus can be a rare but emerging cause of intrauterine infection complicated by post-partum bacteremia. There is possibility of colonization of maternal genital tract with S. gallolyticus causing neonatal infection.

Ischemic stroke in patients that recover from COVID-19: Comparisons to historical stroke prior to COVID-19 or stroke in patients with active COVID-19 infection.

BACKGROUND AND PURPOSE: Understanding the relationship of COVID-19 to stroke is important. We compare characteristics of pre-pandemic historical stroke (Pre-C), cases in acute COVID infection (Active-C) and in patients who have recovered from COVID-19 infection (Post-C). METHODS: We interrogated the Qatar stroke database for all stroke admissions between Jan 2019 and Feb 2020 (Pre-C) to Active-C (Feb2020-Feb2021) and Post-C to determine how COVID-19 affected ischemic stroke sub-types, clinical course, and outcomes prior to, during and post-pandemic peak. We used the modified Rankin Scale (mRS) to measure outcome at 90-days (mRS 0-2 good recovery and mRS 3-6 as poor recovery). For the current analysis, we compared the clinical features and prognosis in patients with confirmed acute ischemic stroke. RESULTS: There were 1413 cases admitted (pre-pandemic: 1324, stroke in COVID-19: 46 and recovered COVID-19 stroke: 43). Patients with Active-C were significantly younger, had more severe symptoms, fever on presentation, more ICU admissions and poor stroke recovery at discharge when compared to Pre-C and Post-C. Large vessel disease and cardioembolic disease was significantly more frequent in Active-C compared to PRE-C or post-C. CONCLUSIONS: Stroke in Post-C has characteristics similar to Pre-C with no evidence of lasting effects of the virus on the short-term. However, Active-C is a more serious disease and tends to be more severe and have a poor prognosis.

Acute multifocal retinitis in a patient with Q fever (Coxiella Burnetii infection) with endocarditis.

OBJECTIVE: To report acute multifocal retinitis in association with serologically-proven Coxiella (C) Burnetii infection (Q fever) with endocarditis. MATERIAL AND METHODS: A single case report documented with multimodal imaging. RESULTS: A 67-year-old cattle breeder presented with a 2-week history of persistent fever, headache, and floaters in both eyes. On examination, his best-corrected visual acuity was 20/20, and there was 1+ vitreous cells in both eyes. Bilateral fundus examination showed multiple small superficial white retinal lesions scattered in the posterior pole and midperiphery associated with a few retinal hemorrhages. These retinal lesions did not stain on fluorescein angiography (FA) and showed focal hyperreflectivity and thickening primarily involving the inner retinal layers on optical coherence tomography (OCT). There also was a band-like hyper-reflective area in the middle retina consistent with paramacular acute middle maculopathy. Transthoracic echocardiogram (TTE) showed a mobile echodensity on the anterior aortic leaflet consistent with a diagnosis of endocarditis. Elisa assays performed on paired serum samples collected 2 weeks apart showed increase in antibodies against C burnetii from 60 IU/ml to 255 IU/ml. The patient was treated with doxycycline 100 mg twice a day for 18 months, with subsequent resolution of the endocarditis. Sequential ocular examinations showed gradual resolution of all acute retinal findings without visible scars. CONCLUSION: Acute Q fever, caused by C burnetii infection, should be considered in the differential diagnosis of acute multifocal retinitis. A systematic cardiac assessment with echocardiography is essential for early diagnosis of associated endocarditis and for prompt administration of appropriate antibiotic treatment to improve clinical outcomes.

Case Report: Purtscher-like retinopathy in a patient with lung adenocarcinoma.

This case report describes an unreported case of  Purtscher-like retinopathy in a patient with pulmonary adenocarcinoma. A 39-year-old man was hospitalized for exploration of a hemoptysis and bilateral blurry vision. Fundoscopic examination showed multiple areas of retinal whitening in the peripapillary area. A chest computed tomography scan then showed a ground glass opacity in the right upper lobe associated to a hilar lymphadenopathy. A thoracotomy and lung biopsy were performed concluding with the diagnosis of lung adenocarcinoma. The patient was treated with high-dose corticosteroids and received Taxol-Carboplatin chemotherapy with good visual outcomes. The article discusses furthermore the importance of including pulmonary adenocarcinoma to the list of systemic conditions for Purtscher-like retinopathy.

Characteristics and comparisons of acute stroke in "recovered" to "active COVID-19 and "pre-pandemic" in Qatar database.

Understanding the relationship of COVID-19 to stroke is important. We compare characteristics of pre-pandemic stroke (PPS), cases in acute COVID infection (CS) and in patients who have recovered from COVID-19 infection (RCS). We interrogated the Qatar stroke database for all stroke admissions between Jan 2020 and Feb 2021 (PPS) to CS and RCS to determine how COVID-19 affected ischemic stroke sub-types, clinical course, and outcomes prior to, during and post-pandemic peak. There were 3264 cases admitted (pre-pandemic: 3111, stroke in COVID-19: 60 and recovered COVID-19 stroke: 93). Patients with CS were significantly younger, had more severe symptoms, fever on presentation, more ICU admissions and poor stroke recovery at discharge when compared to PPS and RCS. Large vessel disease and cardioembolic disease was significantly higher in CS compared to PPS or RCS. There was a significant decline in stroke mimics in CS. Stroke in RCS has characteristics similar to PPS with no evidence of lasting effects of the virus on the short-term. However, CS is a more serious disease and tends to be more severe and have a poor prognosis.

Salmonella-induced pulmonary and pericardial abscesses in a patient presenting with subacute cough.

The non-typhoid Salmonella (NTS) species are commonly associated with gastroenteritis and other forms of intestinal disease. Thoraco-pulmonary infections are less commonly reported. We describe the case of a 66-year-old Qatari lady who presented with subacute cough. Chest imaging revealed multiple pulmonary and a pericardial cavitary lesion with air fluid levels. Bronchoalveolar lavage culture grew Salmonella species group D. The patient was treated with 4 weeks of appropriate antibiotics. Clinical and radiological improvement were documented on subsequent follow up. To our knowledge, this is the first reported case of pulmonary and pericardial salmonella abscesses in the state of Qatar.

Draft Genome Sequence of Rhodotorula mucilaginosa from an Adult Patient in Qatar.

Rhodotorula mucilaginosa is an opportunistic fungal pathogen of public health importance. We present the draft genome sequence of an isolate (Rhodo3571) cultured from an immunocompetent patient. The isolate is similar to other R. mucilaginosa genomes in the NCBI database. Presented here are the genome assembly and its comparison to other reference genomes.

Clinical characteristics and risk factors for COVID-19-associated Candidemia.

Patients with COVID-19-associated candidemia (CAC) in an intensive care unit (ICU) were matched 1:2 with those without candidemia, based on ICU admission date and length of stay in ICU being at least equal to that before candidemia in the corresponding case. The incidence rate of CAC was 2.34 per 1000 ICU days. Eighty cases could be matched to appropriate controls. In the multivariate conditional logistic regression analysis, age (P 0.001), and sequential organ failure assessment score (P 0.046) were the only risk factors independently associated with CAC. Tocilizumab and corticosteroids therapy were not independently associated with candidemia. LAY SUMMARY: In COVID-19 patients who need medical care in an intensive care unit, the risk of developing bloodstream Candida infection is higher in older patients and in those who have a more severe critical illness. Treatment with steroids or tocilizumab does not seem to affect the risk of candida bloodstream infection in these patients.

Disseminated life threatening Nocardia otitidiscaviarum infection in a young female with newly diagnosed systemic lupus erythematosus, case report and review of literature.

Infection due to Nocardia is reported mainly in immunocompromised patients. It usually presents as a pulmonary or disseminated disease with a predilection for the brain. Infections are a rare etiology of intracranial vascular aneurysms. Herein we report a case of disseminated Nocardia otitidiscaviarum (N. otitidiscaviarum) in a young female newly diagnosed with systemic lupus erythematosus (SLE) complicated by the development of an infectious intracranial aneurysm. To the best of our knowledge this is the fourth case of nocardial infection-related intracranial aneurysm and the second case of N. otitidiscaviarum infection to be reported in a patient with systemic lupus erythematosus. Features of previously reported N. otitidiscaviarum related intracranial aneurysm are reviewed.