Deml, Sharon M.

Abstract Alternaria spp. are dematiaceous ascomycetes that can cause opportunistic infections in immunocompromised hosts. They are challenging to identify and treat. However, optimal antifungal therapy remains undefined. We retrospectively reviewed antifungal susceptibilities (AST) of all Alternaria spp. isolates from adults at a tertiary care center between 2011 and 2025. We evaluated culture sources, minimum inhibitory concentration (MIC) and minimal effective concentration (MEC) distributions, and MIC₅₀/MIC₉₀ and MEC50/MEC90 values. Clinical characteristics, treatment measures, and outcomes of patients with clinically significant Alternaria spp. infections were described. Forty-one patients had Alternaria spp. isolated, most commonly from skin (n = 13), bone/joint (n = 5), nail (n = 3), or cornea (n = 3). Posaconazole and itraconazole demonstrated low MICs (MIC₅₀/MIC₉₀: 0.06/0.5 and 0.25/0.5 µg/mL, respectively). Voriconazole and isavuconazole showed higher MIC₅₀/MIC₉₀ (1/2 and 2/4 µg/mL). Caspofungin (0.125/0.5 µg/mL) and amphotericin B (0.25/1 µg/mL) had low MICs and MECs.s. Alternaria spp. represented clinically significant infection in 27 cases (66%); 26% were solid organ transplant recipients and 15% had hematologic malignancies. Other risk factors included preceding trauma (22%) and autoimmune disease (15%). Posaconazole was the most frequently used empiric agent (6, 32%). Following AST results, 14 patients (52%) received oral antifungal therapy; posaconazole was used in all 14. In addition, 7 patients (26%) received combination therapy with IV amphotericin B. Adjunctive surgery occurred in 14 cases (52%). Five patients (19%) died before completing therapy; Alternaria infections occurred predominantly in immunocompromised hosts and were frequently managed with posaconazole and surgery. Interpretive criteria for Alternaria spp. are needed to guide empiric and definitive therapy.

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 Bloodstream infections (BSIs) caused by opportunistic yeasts, namely those of the genus Candida , demonstrate strikingly high mortality rates and require early therapeutic intervention to optimize patient outcomes. Advancements in microbiological diagnosis of BSIs have introduced rapid molecular methods, including multiplex PCR panels, to detect common organisms directly from blood culture media. The BIOFIRE FilmArray Blood Culture Identification 2 (BCID2) assay is one such method and detects seven of the most common yeast species responsible for fungemia, enabling timelier therapeutic optimization by clinicians. Here, we evaluated the clinical performance of BCID2 for yeast identification from positive blood cultures between 2021 and 2025 at a tertiary medical center, compared to the reference standard method, which couples subculturing and diagnostic mass spectrometry. A total of 252 individual yeast identification events were confirmed using the reference method during our study period, 33 (13%) of which represent organisms that lack BCID2 PCR-based targets and 219 (87%) represent organisms targeted by this assay. Of the 219 identifications compatible with the BCID2 panel targets, 209 (95%) were correctly identified. Discordance between BCID2 and the reference method commonly stemmed from the inability of BCID2 to target all yeasts encountered clinically in blood culture, as well as its reduced accuracy in cultures where >1 yeast is present. Overall, these data suggest that the BCID2 assay is a rapid and accurate method to identify the most common organisms causing yeast BSI from blood culture; however, subculture-based reference techniques are important complementary tools in the clinical microbiology laboratory. IMPORTANCE Invasive fungal diseases, including bloodstream infections (BSIs) caused by yeasts, are increasing in prevalence alongside the growing global population of immunocompromised individuals. Prompt and targeted treatment is necessary for effective management of yeast BSI, and microbiological diagnostics play an important role in tailoring patient treatment. Rapid molecular assays that simultaneously detect multiple pathogens associated with a specific syndrome are attractive strategies to expedite pathogen identification. This includes the BIOFIRE FilmArray Blood Culture Identification 2 (BCID2) assay, which detects 33 organisms including 7 yeasts commonly associated with fungemia, directly from blood culture media. Its performance has been well established for the detection of bacteria and bacterial resistance markers from blood cultures. Here, we provide a yeast-specific snapshot into the microbiological performance of BCID2, highlighting its accuracy as well as limitations in detecting medically important yeasts compared to standard culture-based identification from a four-year specimen cohort collected in a tertiary care hospital.

AbstractBackgroundThere are no established clinical breakpoints for antifungal agents against Cryptococcus species; however, epidemiological cut‐off values can help distinguish wild‐type (WT) isolates without any acquired resistance from non‐WT strains, which may harbour resistance mechanisms.Patients/MethodsWe describe the trends of antifungal MICs and percentages of WT C. neoformans species complex (CNSC) isolates processed in our reference laboratory from November 2011 to June 2021. There were only nine isolates in 2011, thus, we included them in the year 2012 for data analysis. Clinical data is also described when available.ResultsWe identified 632 CNSC, the majority collected from blood (n = 301), cerebrospinal fluid (n = 230), and respiratory (n = 71) sources. The overall percentage of WT isolates for amphotericin B (AMB), 5‐flucytosine, and fluconazole was 77%, 98%, and 91%, respectively. We noticed a statistically significant change in the percentage of AMB WT isolates over the years, with 98% of isolates being WT in 2012 compared to 79% in 2021 (p < .01). A similar change was not observed for other antifungal agents. Clinical data was available for 36 patients, primarily non‐HIV immunocompromised patients with disseminated cryptococcosis. There were no statistically significant differences in the clinical characteristics and outcomes between patients with WT (58.3%) versus non‐WT (41.7%) isolates, but we noticed higher mortality in patients infected with an AMB non‐WT CNSC isolate.ConclusionsWe observed an increase in the percentage of AMB non‐WT CNSC isolates in the past decade. The clinical implications of this finding warrant further evaluation in larger studies.

Abstract Background Invasive Mold Infections (IMI) cause significant morbidity and mortality, particularly in patients with hematologic malignancies (HM) and hematopoietic stem cell transplant (HSCT) recipients. Although the risk has significantly decreased with the use of triazole agents as primary prophylaxis, breakthrough infections still occur. Risk factors for IMI have been well-described. Limited data exist on factors predicting mortality. Methods We identified cases using the Cancer registry and Microbiology data at Mayo Clinic Minnesota from 11/19/2011–8/6/2021 and Mayo Clinic Arizona and Florida from 09/13/2017–11/19/2021. We conducted a retrospective review to identify cases of proven/probable IMI per EORTC/MSG criteria. Patients who received at least 7 days of anti-mold prophylaxis were considered having breakthrough infection (Br-IMI). Survival function was estimated using the Kaplan-Meier method. We evaluated predictors of mortality using Cox regression analysis. Results 401 cases of IMI were included (80.2% aspergillosis, 10.2% fusariosis, 8.4% mucormycosis, 1.2% scedosporiosis). 189 patients had proven/probable and 212 had possible disease. 12-week mortality for the entire cohort was 33%. There were 87 cases of Br-IMI (21.6%) on mold-active prophylaxis (posaconazole n=54, voriconazole n=26, isavuconazole n=5, itraconazole n=1, liposomal amphotericin B n=1). A comparison between patients not receiving prophylaxis and those with Br-IMI is shown in Table 1. Higher proportion of patients with Br-IMI had prolonged neutropenia/lymphopenia and graft-versus-host disease involving the gastrointestinal tract or lungs. Positive Aspergillus galactomannan (index ≥ 1.0) was seen more in patients who were not on mold-active prophylaxis. Mortality was 31.5% in patients not receiving prophylaxis and 41.3% with Br-IMI (Figure 1). In multivariate analysis, age, prolonged neutropenia, active HM, Br-IMI and HSCT were associated with increased mortality (Table 2). Conclusion In this cohort, the rate of Br-IMI was significant despite the use of primary prophylaxis (mainly posaconazole). Mortality was higher in patients with Br-IMI compared to those not receiving mold-active prophylaxis. Therefore, clinicians should remain alert to the possibility of Br-IMI. Disclosures Paschalis Vergidis, MD, AbbVie: DSMB|Cidara: Grant/Research Support|Scynexis: Grant/Research Support.

Abstract Background There are not established clinical breakpoints (CBP) for antifungals against Cryptococcus species; However, the analysis of their MICs using epidemiological cut-off values (ECVs) can help to distinguish wild-type (WT) isolates from non-WT strains that may harbor intrinsic or acquired resistance to antifungals. Herein, we analyze the MIC distribution of antifungals against Cryptococcus spp. isolated over the last decade at our reference laboratory. Methods We conducted a retrospective evaluation of antifungals MICs for Cryptococcus neoformans and Cryptococcus gattii complex isolates from various sources that were processed at the Mayo Clinic Laboratory from November 18, 2011 to June 7, 2021. Antifungal susceptibility testing was performed by the Clinical & Laboratory Standards Institute (CLSI) standards (CLSI M59-ED3:2020). We used recommended ECVs to define if the isolates were WT or non-WT, and described the change in the percentage of WT isolates over time. Results During the study period, C. neoformans was isolated from 632 samples collected from 533 patients. Sample sources included cultures from blood (n=301), cerebrospinal fluid (n=230), respiratory (n=71), and other sources (n=30). The overall percentage of WT isolates for amphotericin B (AMB), 5-flucytosine, and fluconazole were 77%, 98% and 91% respectively with no significant difference based on various sources (Table). We noticed an overall increase in MICs for AMB, with 100% WT isolates in 2011 compared to 79% in 2021. No such increase was seen for fluconazole or 5-Flucytosine (Figure). Irrespective of the source or the year of isolation, WT strains for itraconazole, voriconazole, and posaconazole were consistently &gt; 93%. C. gattii was isolated from 16 samples, and 94% were WT strains for AMB and 100% for the other antifungals. CLSI, Clinical and Laboratory Standard Institute; CSF, cerebrospinal fluid; ECVs, epidemiologic cut-off values. AMB, amphotericin B; FLU, fluconazole; 5FC, 5-flucytosine. Conclusion In the last decade, we have observed an overall increase in MICs of AMB for C. neoformans. The number of WT strains for other antifungals was high and not significantly changed during the study frame. Further studies are needed to identify the clinical implications of these findings. Disclosures Paschalis Vergidis, MD, AbbVie: DSMB|Cidara: Grant/Research Support|Scynexis: Grant/Research Support.

Abstract Background Mycobacterium septicum is a rapidly growing non-tuberculous mycobacterium. It is a ubiquitous organism capable of causing infections in both healthy and immunocompromised individuals. Only a few cases have been reported to date, and standard therapeutic regimens, and optimal treatment duration have not been defined. Methods We conducted a retrospective chart review of all patients seen at Mayo Clinic in Rochester, MN from July 2014 to March 2020 from whom Mycobacterium septicum was isolated in culture by our clinical microbiology laboratory. Results There were 12 patients identified with M. septicum infection – 7 males and 5 females. The average age was 67 years, with an age range of 48 to 80 years. Seven of 12 isolates obtained were from sputum samples. Only one patient was on immunosuppressive medication. Three cases were considered clinically significant infections for which directed anti-mycobacterial therapy was instituted. In two of these three cases, co-infection with Mycobacterium avium complex (MAC) was seen. Underlying structural lung disease was present in the two cases of pulmonary infections. Peritoneal dialysis catheter-related peritonitis was seen in the third case. All the isolates were susceptible to amikacin, ciprofloxacin, imipenem, linezolid, moxifloxacin, and trimethoprim-sulfamethoxazole (TMP-SMX). The isolates were resistant to clarithromycin and doxycycline. Patient Characteristics, Associated M. septicum Illness, and Therapy Provided Antimicrobial Susceptibility Profiles of the Mycobacterium septicum Isolates, MIC (mcg/mL) and Interpretation Patient Demographics and Specimen Source of Mycobacerium septicum Isolates Conclusion M. septicum is an unusual cause of non-tuberculous mycobacterial infection. The presence of a foreign body may increase the risk of infection. Individuals with underlying structural lung disease are also likely to be at increased risk of developing pulmonary infection. Generalized treatment recommendations are limited by the lack of prospective controlled trials; hence, optimal antibiotic regimen and treatment duration have not been firmly established. Susceptibility testing should be performed to guide treatment selection, but the use of combination therapy with potentially empiric agents like amikacin, ciprofloxacin, imipenem, linezolid, moxifloxacin, and TMP-SMX as demonstrated in this small study, can be considered. A high rate of macrolide resistance was noted in our study. Disclosures All Authors: No reported disclosures

Mycobacterium septicum is a rarely identified nontuberculous mycobacterium capable of causing infections in both healthy and immunocompromised individuals. Only a few cases of M. septicum infections have been reported, which makes recognizing corresponding clinical disease more challenging for clinicians. Antimicrobial susceptibility profiles for this organism are not well described, and corresponding optimal therapeutic regimens have not been established. We report a tertiary care center’s experience with M. septicum from 2014 to 2020.

Nocardia species are found worldwide and are opportunistic pathogens of both immunocompromised and immunocompetent hosts. Recent updates to the taxonomy of this genus have indicated that there are more than 90 recognized species of Nocardia with 54 species reported to be clinically relevant.

ABSTRACT The value of matrix-assisted laser desorption ionization−time of flight mass spectrometry (MALDI-TOF MS) for the identification of bacteria and yeasts is well documented in the literature. Its utility for the identification of mycobacteria and Nocardia spp. has also been reported in a limited scope. In this work, we report the specificity of MALDI-TOF MS for the identification of 162 Mycobacterium species and subspecies, 53 Nocardia species, and 13 genera (totaling 43 species) of other aerobic actinomycetes using both the MALDI-TOF MS manufacturer's supplied database(s) and a custom database generated in our laboratory. The performance of a simplified processing and extraction procedure was also evaluated, and, similar to the results in an earlier literature report, our viability studies confirmed the ability of this process to inactivate Mycobacterium tuberculosis prior to analysis. Following library construction and the specificity study, the performance of MALDI-TOF MS was directly compared with that of 16S rRNA gene sequencing for the evaluation of 297 mycobacteria isolates, 148 Nocardia species isolates, and 61 other aerobic actinomycetes isolates under routine clinical laboratory working conditions over a 6-month period. MALDI-TOF MS is a valuable tool for the identification of these groups of organisms. Limitations in the databases and in the ability of MALDI-TOF MS to rapidly identify slowly growing mycobacteria are discussed.