Capnocytophaga is a gram-negative, facultative anaerobe. Human infection is rare but can lead to devastating outcomes. Capnocytophaga canimorsus can cause sepsis following an animal bite, whereas human-oral–associated Capnocytophaga infections were reported in immunocompromised patients. Current data on these infections are not robust. Our goal is to provide a contemporary description of a unique characteristic of Capnocytophaga infections. We performed a retrospective review of all patients with Capnocytophaga infection from January 2010 to August 2020 at 3 main hospitals of Mayo Clinic in Rochester, Minnesota; Scottsdale, Arizona; and Jacksonville, Florida. We collected baseline demographic data, clinical characteristics, microbiological data, and outcomes of C. canimorsus and human-oral–associated Capnocytophaga infection. Among 82 patients with Capnocytophaga infection, 46 patients (56.0%) had bacteremia. The most common species identified in this group was C. sputigena (57.9%), followed by C. canimorsus (34.8%). Patients with human-oral–associated Capnocytophaga bacteremia were often immunocompromised, presented with neutropenic fever, and had worse 6-month all-cause mortality compared to C. canimorsus bacteremia (36.4% vs 6.2%, P = .03). They also had a higher β-lactamase production rate (36.4% vs 0.0%, P = .02). Among patients without bacteremia, the main clinical syndrome was polymicrobial head and neck infections (47.2%). Human-oral–associated Capnocytophaga bacteremia occurs primarily in immunocompromised patients, particularly those with hematologic malignancy. In contrast, C. canimorsus bacteremia is more likely to present with community-onset infection related to zoonotic exposure. Human-oral–associated Capnocytophaga infection without bacteremia is frequently isolated in polymicrobial infection; this phenomenon’s significance is yet to be fully understood.

Blood culture-negative infective endocarditis (BCNE) is a challenging condition associated with significant morbidity and mortality. This review discusses the epidemiology, microbiology, diagnosis, and treatment of BCNE considering advancements in molecular diagnostics and increased access to cardiac surgery. BCNE can be categorized into bacterial endocarditis with sterilized blood cultures due to previous antibiotic treatment, endocarditis caused by fastidious microorganisms, and true BCNE caused by intracellular organisms that cannot be cultured using traditional techniques. Non-infectious causes such as nonbacterial thrombotic endocarditis should also be considered. Diagnostic approaches involve thorough patient history; blood and serum testing, including appropriate handling of blood cultures; serological testing; and molecular techniques such as targeted and shotgun metagenomic sequencing. Where available, evaluation of explanted cardiac tissue through histopathology and molecular techniques is crucial. The therapy for BCNE depends on the likely causative agent and the presence of prosthetic material, with surgical intervention often required.

Accurate microbiologic diagnosis is important for appropriate management of infectious diseases. Sequencing-based molecular diagnostics are increasingly used for precision diagnosis of infections. However, their clinical utility is unclear. We conducted a retrospective analysis of specimens that underwent 16S ribosomal RNA (rRNA) gene polymerase chain reaction (PCR) followed by Sanger sequencing at our institution from April 2017 through March 2019. A total of 566 specimens obtained from 460 patients were studied. Patients were considered clinically infected or noninfected based on final diagnosis and management. In 17% of patients, 16S rRNA PCR/sequencing was positive and in 5% of patients, this test led to an impact on clinical care. In comparison, bacterial cultures were positive in 21% of patients. Specimens with a positive Gram stain had 12 times greater odds of having a positive molecular result than those with a negative Gram stain (95% confidence interval for odds ratio, 5.2–31.4). Overall, PCR positivity was higher in cardiovascular specimens (37%) obtained from clinically infected patients, with bacterial cultures being more likely to be positive for musculoskeletal specimens (P < .001). 16S rRNA PCR/sequencing identified a probable pathogen in 10% culture-negative specimens. 16S rRNA PCR/sequencing can play a role in the diagnostic evaluation of patients with culture-negative infections, especially those with cardiovascular infections.

To report the Mayo Clinic experience with COVID-19 related to patient outcomes. We conducted a retrospective chart review of patients diagnosed with COVID-19 between March 1, 2020 and July 31, 2020 at any of the Mayo Clinic sites. We abstracted pertinent comorbidities such as age, gender, body mass index, Charlson Comorbidity Index (CCI) variables, and treatments received. Factors associated with hospitalization and mortality were assessed in univariate and multivariate models. A total of 7,891 patients with confirmed COVID-19 with research authorization on file received care across the Mayo Clinic during the study period. Of these, 7217 patients were adults ≥ 18 years old which were analyzed further. 897 (11.3%) patients required hospitalization, and 354 (4.5%) patients received care in the Intensive Care Unit (ICU). All hospitalized patients were reviewed by a COVID-19 Treatment Review Panel, and 77.5% of inpatients received a COVID-19 directed therapy. Overall mortality was 1.1%, with 7.1% mortality in hospitalized patients and 11.9% in patients requiring ICU care. Mayo Clinic outcomes of COVID-19 patients in the ICU, hospital and community compare favorably to those reported nationally. This likely reflects the impact of interprofessional multidisciplinary team evaluation, effective leveraging of clinical trials and available treatments, deployment of remote monitoring tools, and maintenance of adequate operating capacity to not require surge adjustments. These best practices can help guide other health care systems with the continuing response to the COVID-19 pandemic.

Powassan virus (POWV) is an emerging arthropod-borne flavivirus, transmitted by Ixodes spp ticks, which has been associated with neuroinvasive disease and poor outcomes. A retrospective study was conducted at Mayo Clinic from 2013 to 2022. We included clinical and epidemiological data of probable and confirmed neuroinvasive POWV cases. Sixteen patients with neuroinvasive POWV were identified with a median age of 63.2 years and 62.5% were male. Six patients presented with rhombencephalitis, four with isolated meningitis, three with meningoencephalitis, two with meningoencephalomyelitis, and one with opsoclonus myoclonus syndrome. A median time of 18 days was observed between symptom onset and diagnosis. Cerebrospinal fluid analysis showed lymphocytic pleocytosis with elevated protein and normal glucose in the majority of patients. Mortality within 90 days occurred in three cases (18.8%), and residual neurological deficits were seen in eight (72.7%) survivors. To our knowledge, this is the largest case series of patients with neuroinvasive POWV infection. We highlight the importance of a high clinical suspicion among patients that live in or travel to high-risk areas during the spring to fall months. Our data show high morbidity and mortality among patients with neuroinvasive disease.

Clinical significance of a single positive blood culture bottle (SPBCB) with Staphylococcus aureus is unclear. We aimed to assess the significance of an SPBCB by looking at the associated outcomes. We performed a retrospective, multicenter study of patients with an SPBCB with S aureus using data collected from both electronic health records and the clinical microbiology laboratory. Overall, 534 patients with S aureus bacteremia were identified and 118 (22.1%) had an SPBCB. Among cases with an SPBCB, 106 (89.8%) were classified as clinically significant whereas 12 (10.2%) were considered contaminated or of unclear significance. A majority (92.4%) of patients received antibiotic therapy, but patients with clinically significant bacteremia were treated with longer courses (25.9 vs 5.7 days, P < .001). Significant differences in both frequency of echocardiography (65.1% vs 84.6%, P < .001) and infective endocarditis diagnosis (3.8% vs 14.2%, P = .002) were seen in those with an SPBCB compared to those with multiple positive bottles. A longer hospital length of stay and higher 90-day, 6-month, and 1-year mortality rates were seen in patients with multiple positive blood culture bottles. An SPBCB with S aureus was common among our patients. While this syndrome has a more favorable prognosis as compared to those with multiple positive blood cultures, clinicians should remain concerned as it portends a risk of infective endocarditis and mortality.