Genomic analysis of Staphylococcus aureus isolates from bacteremia reveals genetic features associated with the COVID-19 pandemic (preprint)

Genomic analyses of bacterial isolates are necessary to monitor the prevalence of antibiotic resistance genes and virulence determinants. Herein, we provide a comprehensive genomic description of a collection of 339 Staphylococcus aureus strains isolated from patients with bacteremia between 2014 and 2022. Nosocomial acquisition accounted for 56.6% of episodes, with vascular catheters being the predominant source of infection (31.8%). Cases of fatality (27.4%), persistent bacteremia (19.5%) and diagnosis of septic emboli (24.2%) were documented. During the COVID-19 pandemic, we observed a 140% increase of the episodes of S. aureus bacteremia per year, with a concomitant increase of the cases from nosocomial origin. This prompted us to investigate the existence of genetic features associated with S. aureus isolates from the COVID-19 pandemic. While genes conferring resistance to {beta}-lactams (blaI-blaR-blaZ), macrolides (ermA, ermC, ermT, mphC, msrA) and aminoglycosides (ant(4)-Ia, ant(9)-Ia, aph(3)-IIIa, aph(2)-Ih) were prevalent in our collection, detection of the msrA and mphC genes increased significantly in pandemic S. aureus isolates. Similarly, we observed a higher prevalence of isolates carrying the genes encoding the Clumping Factors A and B, involved in fibrinogen binding. Of note, macrolides were extensively used as accessory therapy for COVID-19 and fibrinogen levels were usually elevated upon SARS-CoV-2 infection. Therefore, our results reveal a remarkable adaptation of the S. aureus isolates to the COVID-19 pandemic context and demonstrates the potential of whole-genome sequencing to conduct molecular epidemiology studies.

Overview of FDA Circulatory System Devices Panel virtual meeting on TriGUARD 3 cerebral embolic protection.

Despite advances in transcatheter aortic valve replacement (TAVR) technology, periprocedural stroke remains a complication of TAVR procedures. The TriGUARD 3 device is designed to be positioned in the aortic arch to deflect debris away from the brachiocephalic, left common carotid, and left subclavian arteries during TAVR. The United States Food and Drug Administration (FDA) assembled the Circulatory System Devices Panel to review safety and effectiveness data for the TriGUARD 3 device. Because of the coronavirus disease 2019 pandemic, this meeting was held virtually. In this manuscript, we summarize the data presented by both the sponsor and FDA, as well as the panel discussion.

[A case of cerebral embolism with Coronavirus disease 2019].

A 63-year-old man, who had persistent fever for a month, was admitted to the hospital with sudden left arm palsy with a National Institutes of Health Stroke Scale score of 3. Consequently, brain MRI showed hyperintensity of the bilateral occipital, right parietal, and right frontal lobes on diffusion-weighted imaging. Moreover, FLAIR presented hyperintensity of the left occipital lobe. Magnetic resonance angiography detected the deficit of the blood-flow signal of the horizontal segment of the middle cerebral artery. He was diagnosed with acute ischemic stroke. In addition, chest CT showed ground-glass opacities, and test to detect SARS-CoV-2 was positive. Cerebral embolism was suspected. However, the source was unknown. His ischemic stroke was possibly associated with coagulation abnormality caused by coronavirus disease 2019.

Transcranial Doppler Ultrasound Evidence of Active Cerebral Embolization in COVID-19.

OBJECTIVE: To report six consecutive patients with confirmed coronavirus disease-2019 (COVID-19) who underwent Transcranial Doppler (TCD) ultrasonography evaluation for cerebral microemboli in the setting of suspected or confirmed acute ischemic stroke. METHODS: Patient data were obtained from medical records from Northwestern Memorial Hospital, Chicago, IL between May and June 2020. All patients with confirmed COVID-19 who underwent clinical TCD ultrasonography for microemboli detection were included. RESULTS: A total of eight TCD studies were performed in six patients with COVID-19 (4 men and 2 women, median age 65±5), four with confirmed ischemic stroke and two with refractory encephalopathy. Microemboli were detected in three male patients, two patients had suffered a confirmed ischemic stroke and one who developed prolonged encephalopathy. Microemboli of varying intensity were identified in multiple vascular territories in two patients, and microemboli persisted despite therapeutic anticoagulation in a third patient. Of the three patients without evidence of microemboli on TCD ultrasonography, two patients had suffered a confirmed ischemic stroke, while one remained with refractory encephalopathy. CONCLUSIONS: TCD ultrasonography for microemboli detection identified three patients with confirmed COVID-19 with evidence of cerebral arterial microemboli, including one who was therapeutically anticoagulated. TCD ultrasonography provides a non-invasive method for evaluating cerebral microemboli in patients with COVID-19 and may be useful in assessing response to treatment in cases with suspected or confirmed disorders of hypercoagulability. Further studies investigating the prevalence of cerebral microemboli and associated risk factors are needed to characterize their pathogenic mechanism and guide therapeutic interventions in hospitalized COVID-19 patients.