Little is known regarding SARS-CoV-2 infection risk following SARS-CoV-2 exposures in hospitalized patients. Amongst 11,997 patients in 14 hospitals exposed 2020–2023, 6.5% tested positive (median 3d after exposure). Positivity rates were 6.7% vs 5.8% for Omicron vs pre-Omicron exposures (P = 0.07) and 7.6% vs 4.6% for exposures before vs after admission (P < 0.001).

In laboratory testing, a mobile enclosed disinfection cabinet using ultraviolet-C light and aerosolized hydrogen peroxide was effective for disinfection of hard and soft surfaces. The addition of aerosolized hydrogen peroxide to ultraviolet-C light resulted in improved disinfection of soft surfaces and Clostridioides difficile spores.

A healthcare-associated group A Streptococcus outbreak involving six patients, four healthcare workers, and one household contact occurred in the labor and delivery unit of an academic medical center. Isolates were highly related by whole genome sequencing. Infection prevention measures, healthcare worker screening, and chemoprophylaxis of those colonized halted further transmission.

Background: Hospital-acquired influenza (HA flu) lacks a consensus definition. However, it is known to be associated with increased inpatient morbidity and mortality. Objective: To describe the clinical course of HA flu in a cohort population. Methods: A retrospective cohort study was conducted at a tertiary-care adult and pediatric teaching hospital. Patients with HA flu during 3 seasons, 2016 through 2019, were identified from medical record information based on timing of the onset of signs and symptoms and positive virologic testing >72 hours after admission. Influenza infection was confirmed by multiplex respiratory PCR, influenza A/B PCR, or direct fluorescent antibody tests. Chart review was performed to abstract patient demographics and comorbidities, length of stay, testing, and timing to antiviral administration as well as diagnosis of pneumonia, coinfections, and 30-day mortality. Escalation of care during hospitalization was defined as a new requirement of supplemental oxygen, invasive or noninvasive ventilation, and transfer to an intensive care unit. Results: During the 3 flu seasons, 132 patients were identified with HA flu; 76 (58%) were women, 6 (4.6%) were aged <18 years, and 126 (95.4%) were adults. Annually, HA-flu patients accounted for 5%–7.8% of all patients hospitalized with laboratory-proven influenza. The median duration between hospitalization and positive flu test was 15 days, and the median length of stay after influenza diagnosis was 6 days. Antiviral treatment was received by 96% of the patients. In total, 41 patients (31%) showed radiographic evidence for pneumonia. Coinfection with either a viral or bacterial pathogen was identified in 25% of the cases. In addition, 26% of the patients experienced an escalation of care, and 20 patients (15%) were transferred to the intensive care unit after HA flu diagnosis. Furthermore, 4 deaths (3%) were attributed to influenza during their hospitalization. Conclusions: HA flu was a frequent cause for escalation in care and was associated with a mortality rate substantially higher than is typically seen in community-based populations with influenza. Coinfection was mostly related to bacteremia and pneumonia, yet not all pneumonias had an associated microbiological diagnosis other than influenza, and there was no significant association between coinfection and mortality. Future work should explore more precise definitions for HA flu as well as its complications.

Funding: None

Disclosures: None

Candida species were once largely regarded merely as causes of aggravating, but rarely life-threatening mucocutaneous infections such as thrush, vulvovaginitis, and intertrigo. Now, however, Candida species have assumed the role of major nosocomial pathogens. This change has paralleled the advent of aggressive cancer chemotherapy, the widespread use of parenteral nutrition, and the practice of advanced surgical techniques including cardiovascular procedures.

Candida is a heterogeneous genus presently grouped with the Fungi Imperfecti (Deuteromycetes). There are over 80 species of Candida; only seven, however, have been recovered from humans: Candida albicans, Candida tropicalis, Candida pseudotropicalis, Candida guilliermondi, Candida krusei, Candida parapsilosis, and Candida stellatoidea. Approximately 90% the systemic Candida infections are due to C. albicans; most of the remaining infections are due to C. tropicalis. Candida species are normal commensals of humans. They are commonly found on the skin, in the gastrointestinal tract, sputum, the female genital tract, and urine from catheterized bladders. C. albicans is found only in human beings and in animal reservoirs. In other sites, such as hospital environments, Candida probably represents contamination by human excreta. Other Candida species may be cultured from soil and other environmental locations. Unlike Aspergillus species, Candida species are uncommon laboratory contaminants.

Automated peritoneal dialysis systems have helped make intermittent peritoneal dialysis an alternative to hemodialysis for long-term management of patients with end-stage renal disease. However, if not cleaned and maintained properly, these machines provide a reservoir for pathogens. The microbiologic barriers in these machines are not impenetrable, but sterile dialy-sate fluid can be produced if the machines are adequately cleaned and disinfected. Potential shortcomings of the microbiologic barriers are discussed, and guidelines to prevent contamination of the internal parts of a machine are suggested.

Infections with Listeria monocytogenes have been increasing in incidence over the last decade. Listeria species are found widely in the environment, frequently isolated from the soil, water, sewage, and from a variety of wild and domestic animals. Outbreaks of human listeriosis have been linked to contaminated coleslaw, milk, and other dairy products. Since Listeria is an intracellular pathogen, it is not surprising that the majority of symptomatic cases have occurred in individuals receiving immunosup pressive therapy, or with some defect in their cell-mediated immune system.

Lyme borreliosis (also known as Lyme disease) has become the most commonly reported tick-transmitted disease in the United States.’ The diverse clinical manifestations of the disease make diagnosis difficult, but Lyme borreliosis is quite responsive to treatment if recognized in the early stages.

In the early part of the century, Afzelius in Sweden and Lipschutz in Austria described a distinctive skin lesion, erythema chronicum migrans (ECM), which developed at the site of a previous tick bite. Later, Garin and Bujadoux in France, Hellerström in Sweden, and Bannwarth in Germany described the association of ECM with neurological diseases, including neuropathies, radiculopathies, and cranial nerve palsies. Lyme disease was first recognized as a separate syndrome in the United States by Dr. Allen Steere and his colleagues in 1976, after a homemaker, MS Polly Murray, brought an outbreak of arthritis to their attention. Epidemiological studies of this unusual geographical clustering of children in Lyme, Connecticut, who were thought to have juvenile rheumatoid arthritis, suggested another process. The illness was eventually found to be caused by a vectorborne spirochete, Borrelia burgdorferi, which is capable of infecting the cardiovascular, dermatologic, neurologic, and musculoskeletal systems.