Saleh, Omar Abu

Abstract Background Invasive listeriosis remains a leading cause of foodborne infection–related mortality in the United States and is associated with substantial case fatality despite appropriate antimicrobial therapy. Owing to the relative rarity of invasive disease, contemporary data evaluating clinical characteristics, optimal antimicrobial strategies, and predictors of mortality remain limited. Methods We conducted a retrospective cohort study of adults with laboratory-confirmed invasive Listeria monocytogenes infection at Mayo Clinic Health System sites from 1980 to 2024. Clinical syndromes were categorized into four mutually exclusive categories, namely bloodstream infection, central nervous system infection, pregnancy-associated infection, and other focal infections. The primary outcome was 1-year all-cause mortality. Secondary outcomes included 90-day mortality and residual neurological deficits among patients with neurolisteriosis. Results Fifty patients were included (median age, 72 years; 56% immunocompromised). The most common clinical presentations were bacteremia (44%) and neurolisteriosis (36%), followed by endovascular infection (12%) and peritonitis (6%). Most patients received a beta-lactam–based regimen, 46% aminopenicillin monotherapy, and 30% received combination therapy with gentamicin. Thirty-day, 90-day, and 1-year mortality were 10%, 12%, and 20%, respectively. Immunocompromised status and intensive care unit admission were associated with an increased risk of 1-year mortality, whereas adjunctive gentamicin therapy was not associated with improved survival. Conclusion Invasive listeriosis is associated with substantial morbidity and mortality, particularly among immunocompromised hosts. Host factors and severity of illness at presentation appear to be key drivers of unfavorable outcomes. Larger multicenter studies are needed to define optimal management strategies.

Background: Itraconazole is the preferred antifungal agent for mild to moderate histoplasmosis and step-down therapy following amphotericin B treatment. Although hydroxy-itraconazole, a major metabolite of itraconazole, displays antifungal activity comparable with that of the parent compound, its role in therapeutic drug monitoring targets for histoplasmosis remains uncertain. Methods: The objective was to compare clinical outcomes and adverse events using itraconazole parent-compound concentrations alone versus combined itraconazole and hydroxy-itraconazole concentrations in patients treated for histoplasmosis. This retrospective cohort study included adults with probable or proven histoplasmosis who received itraconazole and had at least 1 documented serum concentration. The primary outcome was clinical response across 3 groups: (1) parent (itraconazole parent-compound concentration >1.0 mcg/mL), (2) combined (parent-compound concentration <1.0 mcg/mL with combined itraconazole plus hydroxy-itraconazole >1.0 mcg/mL), and (3) subtherapeutic (failure to reach either threshold). Treatment response and adverse events were analyzed using the Fisher exact test. Results: Among 108 patients (parent, n = 40; combined, n = 40; subtherapeutic, n = 28), response rates differed across groups (parent (95%); combined (90%); subtherapeutic (67.9%); P = 0.006). There was no difference between the parent and combined groups. Adverse events did not differ, although drug discontinuation occurred more frequently in the subtherapeutic group (parent (5%); combined (20%); subtherapeutic (25%); P = 0.04). Conclusions: Patients who failed to achieve either an itraconazole concentration >1 mcg/mL or a combined itraconazole plus hydroxy-itraconazole concentration >1 mcg/mL had lower response rates. Similar outcomes among patients achieving the itraconazole target alone and those achieving the combined target suggest that hydroxy-itraconazole concentrations may contribute to therapeutic drug monitoring targets in histoplasmosis.

Abstract Background Lyme arthritis is the most common late manifestation of disseminated Lyme disease in the United States. While most patients respond to antibiotic therapy, a subset develops postantibiotic Lyme arthritis (PALA), characterized by persistent noninfectious inflammatory arthritis. Data describing predictors of PALA and treatment patterns remain limited. Methods We conducted a retrospective observational cohort study of patients with polymerase chain reaction (PCR)−confirmed native joint Lyme arthritis treated at our institution from 2004 to 2025. Clinical, laboratory, imaging, treatment, and outcome data were abstracted from electronic health records. Continuous variables were compared using the Mann–Whitney U test, and categorical variables using Fisher's exact test. Results Seventy-seven patients with PCR-confirmed native joint Lyme arthritis were identified: 64 adults and 13 children. Children more frequently presented with fever and had significantly higher synovial fluid white blood cell counts compared with adults. Knee monoarthritis was the predominant presentation in both groups. Among adults, 41 (64%) achieved complete symptomatic resolution following antibiotic therapy, while 19 (29.7%) developed PALA. Adults who developed PALA had significantly lower synovial fluid white blood cell counts and more extensive joint involvement. The use of intravenous antibiotics and longer total antibiotic duration was more common among PALA patients without evidence of improved outcomes. Conclusions In this cohort of PCR-confirmed native joint Lyme arthritis, a substantial proportion of adults developed PALA. Failure to respond to initial antibiotic therapy and certain clinical features may identify patients at increased risk. These findings support judicious antibiotic use and early consideration of noninfectious mechanisms in persistent arthritis.

Itraconazole is the recommended first-line antifungal agent in blastomycosis treatment. However, pharmacokinetic limitations and adverse drug events may necessitate the use of alternative antifungal agents. The primary objective of the study was to retrospectively describe a cohort of patients with blastomycosis who received voriconazole (as partial or complete therapy), for complete or partial treatment, compared to those who received itraconazole alone. Secondary objectives included rationale for voriconazole selection, treatment response, mortality, and adverse drug events. This retrospective multicenter cohort study included adult patients with proven/probable blastomycosis who received itraconazole or voriconazole. Treatment response was evaluated at one year or end of therapy, whichever came first. Mortality outcomes were assessed within 7 days of the last documented azole dose. Propensity score weighting and subgroup analysis were utilized to control confounding variables between cohorts. A total of 119 patients receiving itraconazole and 25 receiving voriconazole as complete or partial treatment were included. Voriconazole was often selected for CNS involvement or after intolerance to alternative azoles. After propensity score weighting, no significant difference in complete or partial treatment response was observed. Rates of all-cause mortality and blastomycosis-related mortality were numerically higher in the voriconazole cohort. Adverse drug event rates were similar between cohorts; however, discontinuation due to adverse events was more common in the voriconazole cohort. Voriconazole was most utilized for the treatment of blastomycosis in cases with CNS involvement or intolerance to other azoles. A statistically significant difference in response rate was not identified between voriconazole-containing or itraconazole-treated patients; however, given limited sample sizes, further data is needed to assess the equivalency of these agents in the treatment of blastomycosis.

Pasteurella species are facultatively anaerobic Gram-negative coccobacilli residing in the upper respiratory tract of mammals, fowl and domestic animals including cats and dogs. Localized infections with Pasteurella species are common but invasive infections are rare. There is a paucity of data available on risk factors, clinical presentations and outcomes with Pasteurella bloodstream infection. We conducted a retrospective review of patients with Pasteurella bacteremia presenting to our institution. There were 63 presentations (61 patients) with Pasteurella bacteremia. Immunosuppression, malignancy and alcohol misuse were common. Rates of admission to intensive care (n = 18, 29.5%) and death prior to hospital discharge (n = 7, 11.5%) were high.

Abstract The practice patterns of fluorine 18–labeled fluorodeoxyglucose positron emission tomography/computed tomography ([18F] FDG PET/CT) use in cardiac implantable electronic device infection remain undefined. Among 258 Emerging Infections Network respondents, 69% reported never or rarely using [18F] FDG PET/CT. Limited access and insurance barriers were the most common obstacles.

Abstract Background Intravesical Mycobacterium bovis bacillus Calmette-Guérin (BCG) is standard therapy for high-risk nonmuscle-invasive bladder cancer. However, M bovis infections can occur and are not well understood. We aimed to characterize clinical phenotypes, diagnosis, management, and outcomes of culture-confirmed M bovis BCG infections following intravesical therapy for urothelial carcinoma. Methods A retrospective single-center review of adults with culture-confirmed M bovis infection after intravesical BCG (May 2009–July 2024) was conducted, abstracting clinical, microbiologic, treatment, and outcome data. Results Twenty-two White male patients (median age, 77 years) were included; 8 (36.4%) had localized genitourinary infection, 6 (27.3%) had dissemination limited to blood, and 8 (36.4%) had dissemination to other organs. Patients with bloodstream-only infection presented acutely (median 1.5 days after last BCG), whereas those with localized or organ-disseminated disease presented months to years after BCG, with the longest diagnostic delays in organ-disseminated infection. Despite all cases had culture-proven M bovis BCG infection, acid-fast smear, Mycobacterium tuberculosis complex polymerase chain reaction, and histopathology had limited sensitivity. All isolates were susceptible to rifampin, isoniazid, and ethambutol; all were resistant to pyrazinamide. Median treatment duration exceeded 9 months, 94.7% achieved cure, and attributable mortality was 5.0% (1 vascular graft infection). Conclusions M bovis BCG infections following intravesical therapy have favorable outcomes but are often associated with diagnostic delays and prolonged treatment. Early suspicion, comprehensive diagnostic evaluation, and timely surgical source control when indicated are critical. Management strategies should be tailored based on the extent of disease dissemination and individual host factors.

Abstract Patent foramen ovale (PFO) has a prevalence of approximately 25%. Its association with pyogenic brain abscess (PBA) is unclear. We reviewed adults with PBA and known PFO status from 1 January 2009 through 31 December 2021 at Mayo Clinic. High PFO prevalence (40.5%) was seen. PBA patients with PFO had distinct abscess characteristics but unchanged 1-year, all-cause mortality.

Abstract Background Adenovirus is a ubiquitous dsDNA virus with potential for end-organ disease. End-organ or disseminated adenoviral disease (EOD) occurs more frequently in hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients. We aim to characterize the clinical manifestations and outcome of adenovirus viremia in adults, including HSCT and SOT recipients. We describe severity of illness, organ-involvement, and graft and patient survival. Methods This retrospective, multi-site, study enrolled adults patients with positive adenovirus PCR in blood and other clinical specimens from January, 2010 through April, 2025. We excluded patients with insufficient medical records, follow up less than 30 days, and isolated conjunctivitis without viremia. EOD was defined by the presence of clinical signs or symptoms consistent with organ involvement, confirmed by a positive adenovirus PCR or by histopathology. Descriptive and comparative statistics were performed using R. Results Fifty patients with adenovirus viremia were included in this study. The most common immunocompromising conditions were corticosteroid use (84%, n = 42), HSCT (40%, n = 20) and SOT (34%, n = 17) (Table 1). Only 3 patients (6%) had no known immunocompromising condition. 20 patients (40%) had EOD while 30 patients (60%) had isolated viremia. Lungs were the most affected organ, followed by the gastrointestinal tract and liver (Figure 1). EOD was more prevalent in older patients (60 vs. 41 years, p =0.03) and in those with higher initial plasma viral load (673364 vs. 6593, p=0.005). The most common treatment was reduction in immunosuppression (Table 2). Cidofovir was more often used in patients with EOD. Adenovirus-related outcomes were worse in patients with EOD [higher rates of mortality (45% vs. 13.3%) and ICU admission (60% vs. 20%)] vs. without EOD (Table 3). Conclusion Adenovirus viremia is associated with high mortality in a cohort of mostly immunocompromised adults, particularly those with EOD. Older age and a higher initial plasma viral load are associated with EOD. Patients with EOD had worse clinical outcomes such as ICU admission and adenovirus-related mortality. Disclosures All Authors: No reported disclosures