Harjot Kaur Singh

Background: An improved understanding of the epidemiology of hospital-onset methicillin-resistant Staphylococcus aureus bloodstream infection (HO-MRSA BSI) could inform future prevention strategies for HO-MRSA BSI. Methods: We performed a retrospective cohort study of HO-MRSA BSI reported to NHSN from 2020–2023 at a system of 9 acute care hospitals located in New York City. The primary outcome was to describe the demographic and clinical characteristics of patients with HO-MRSA BSI. Secondary outcomes included comparisons of tertiary (TH) and community (CH) hospitals, standardized infection ratio (SIR) and rates per 10,000 patient-discharges, presumptive potential infectious sources, and mortality. Results: Between 2020 and 2023, 222 patients had HO-MRSA BSI. Their median age was 65 years, 139 (63%) were male, 92 (41%) had central lines, 89 (40%) were in ICUs, and 63 (28%) were on a ventilator. These characteristics were similar across the 176 (79%) patients in TH and the 46 (21%) patients in CH. SIRs were similar across each year of the study (with cumulative SIRs of 0.815 overall, 1.412 [CH] and 0.732 [TH]). Overall HO-MRSA BSI rates ranged from 2.58–3.53 per 10,000 patient-discharges. The most common sources of HO-MRSA BSI were pneumonia (41%), SSTIs (17%), CLABSIs (13%), and PIV catheter-related issues (9%). The all-cause mortality rate was 35%. Discussion: The unchanged HO-MRSA BSI SIRs in this study support the need for additional interventions that focus on prevention of the primary sources of MRSA infections. Ongoing systematic surveillance of the primary sources of HO-MRSA BSI should be implemented to inform and monitor best practices for prevention.

With a rising incidence of COVID-19-associated morbidity and mortality worldwide, it is critical to elucidate the innate and adaptive immune responses that drive disease severity. We performed longitudinal immune profiling of peripheral blood mononuclear cells from 45 patients and healthy donors. We observed a dynamic immune landscape of innate and adaptive immune cells in disease progression and absolute changes of lymphocyte and myeloid cells in severe versus mild cases or healthy controls. Intubation and death were coupled with selected natural killer cell KIR receptor usage and IgM+ B cells and associated with profound CD4 and CD8 T cell exhaustion. Pseudo-temporal reconstruction of the hierarchy of disease progression revealed dynamic time changes in the global population recapitulating individual patients and the development of an eight-marker classifier of disease severity. Estimating the effect of clinical progression on the immune response and early assessment of disease progression risks may allow implementation of tailored therapies.

HIV-infected and HIV-exposed, uninfected infants experience a high burden of infectious morbidity and mortality. Hospitalization is an important metric for morbidity and is associated with high mortality, yet, little is known about rates and causes of hospitalization among these infants in the first 12 months of life.

Both the World Health Organization and the United States Department of Health and Human Services have recently substantially revised perinatal HIV treatment guidelines based on emerging data, much of it from the developing world. Management of HIV infection in pregnancy and delivery is complicated by concerns for maternal and fetal drug toxicity, acquisition of antiretroviral resistance, prior therapy, co-infections with other viruses, as well as incident opportunistic infections. Intrapartum and peripartum obstetric management, including the role of Caesarean section, continue to evolve in the setting of maternal HIV infection. Finally, new data have expanded the role of antiviral therapy in allowing safer infant feeding choices for HIV-infected mothers in resource-limited settings.