Fida, Madiha

Abstract Background In contrast to bloodstream infection due to a variety of bacteria in patients with cardiovascular implantable electronic devices (CIED), there are limited data regarding candidemia and risk of CIED infection. Methods All patients with candidemia and a CIED at Mayo Clinic Rochester between 2012 and 2019 were reviewed. Cardiovascular implantable electronic device infection was defined by (1) clinical signs of pocket site infection or (2) echocardiographic evidence of lead vegetations. Results A total of 23 patients with candidemia had underlying CIED; 9 (39.1%) cases were community onset. None of the patients had pocket site infection. The duration between CIED placement and candidemia was prolonged (median 3.5 years; interquartile range, 2.0–6.5). Only 7 (30.4%) patients underwent transesophageal echocardiography and 2 of 7 (28.6%) had lead masses. Only the 2 patients with lead masses underwent CIED extraction, but device cultures were negative for Candida species. Two (33.3%) of 6 other patients who were managed as candidemia without device infection subsequently developed relapsing candidemia. Cardiovascular implantable electronic device removal was done in both patients and device cultures grew Candida species. Although 17.4% of patients were ultimately confirmed to have CIED infection, CIED infection status was undefined in 52.2%. Overall, 17 (73.9%) patients died within 90 days of diagnosis of candidemia. Conclusions Although current international guidelines recommend CIED removal in patients with candidemia, the optimal management strategy remains undefined. This is problematic because candidemia alone is associated with increased morbidity and mortality as seen in this cohort. Moreover, inappropriate device removal or retention can both result in increased patient morbidity and mortality.

Abstract Prototheca is a microalgae known to cause infections in humans, with protothecosis most commonly presenting as olecranon bursitis or localized soft tissue infection. Disseminated disease can be seen in immunocompromised patients. In this retrospective single-institution case series, we describe our experience with 7 patients with Prototheca infections.

Infective endocarditis (IE) is a rare but increasingly prevalent disease with high morbidity and mortality, requiring antimicrobials and at times surgical intervention. Through the decades of healthcare professionals’ experience with managing IE, certain dogmas and uncertainties have arisen around its pharmacotherapy. The introduction of new antimicrobials and novel combinations are exciting developments but also further complicate IE treatment choices. In this review, we provide and evaluate the relevant evidence focused around contemporary debates in IE treatment pharmacotherapy, including beta-lactam choice in MSSA IE, combination therapies (aminoglycosides, ceftaroline), the use of oral antimicrobials, the role of rifamycins, and long-acting lipoglycopeptides.

Antistaphylococcal penicillins (ASP) and cefazolin are first-line treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. Borderline oxacillin resistance (i.e., oxacillin MICs 1-8 μg/mL) is observed in strains hyperproducing beta-lactamases.

Abstract Background Cardiovascular implantable electronic devices (CIED) infection carries significant morbidity, mortality, and financial burden. Bacteremia in patients with CIED increases risk of CIED infection. While several investigations have examined Staphylococcus aureus bacteremia and risk of CIED infection, data regarding non-S. aureus gram-positive coccal (non-SA GPC) bacteremia in patients with CIED has been both limited and dated. The current study examined the clinical characteristics of patients with CIED who developed non-SA GPC bacteremia and their proclivity of CIED infection. Methods We reviewed all patients with CIED who developed non-SA GPC bacteremia at Mayo Clinic between 2012–2019. Cases with a left ventricular assist device, non-hospitalization, and contaminated blood culture were excluded. The 2019 European Heart Rhythm Association International Consensus Document was used to define CIED infection. Results A total of 160 patients with CIED developed non-SA GPC bacteremia during the period. Ninety (56.2%) patients had CIED infection, with 60 (37.5%) classified as definite and 30 (18.8%) possible. This included 41/64 (64.1%) patients with coagulase-negative Staphylococcus (CoNS), 30/41 (73.2%) patients with Enterococcus, 13/19 (68.4%) patients with viridans group streptococci (VGS), and 6/36 (16.6%) patients with other non-SA GPC. The odds of CIED infection (with 95% CI) for CoNS, Enterococcus, and VGS bacteremia were 8.9 (3.2–24.6), 13.6 (4.5–41.6), and 10.8 (2.9–40.0) -fold higher, respectively, as compared to other non-SA GPC. Among those with infected CIED, 51 (56.7%) patients underwent complete device extraction after a median of 6 (IQR 3.5–10) days. In an unadjusted analysis of patients with CIED infection, the reduction in one-year mortality following device removal was not statistically significant (HR 0.59, 95% CI 0.26–1.33, p=0.198). Conclusion The overall prevalence of CIED infection following non-SA GPC bacteremia was higher than previously reported, particularly that due to CoNS, Enterococcus, and VGS. Further study with a larger cohort is needed to demonstrate the survival benefit from CIED extraction in patients with infected CIED due to non-SA GPC. Disclosures Larry M. Baddour, M.D., Boston Scientific: Advisor/Consultant|Botanix Pharmaceuticals: Advisor/Consultant|Roivant Sciences: Advisor/Consultant|UpToDate, Inc.: Royalty payments - authorship duties Rizwan Sohail, M.D., Aziyo Biologics: Advisor/Consultant|Boston Scientific: Advisor/Consultant|Medtronic: Advisor/Consultant|Philips: Advisor/Consultant|Philips: Honoraria Malini Madhavan, M.B.B.S., Biosense Webster: Advisor/Consultant|Biotronik Inc: Advisor/Consultant|Boston Scientific: Grant/Research Support|Convatec: Advisor/Consultant.

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 > 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 Prolonged infections in immunocompromised individuals may be a source for novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants, particularly when both the immune system and antiviral therapy fail to clear the infection and enable within-host evolution. Here we describe a 486-day case of SARS-CoV-2 infection in an immunocompromised individual. Following monotherapy with the monoclonal antibody Bamlanivimab, the individual’s virus acquired resistance, likely via the earliest known occurrence of Spike amino acid variant E484T. Recently, E484T has arisen again as a derivative of E484A in the Omicron Variant of Concern, supporting the hypothesis that prolonged infections can give rise to novel variants long before they become prevalent in the human population.

The detection of antibodies against Histoplasma capsulatum remains a frequently relied-on approach to diagnose histoplasmosis. We retrospectively assessed the performances of complement fixation (CF) and immunodiffusion (ID) assays for anti- Histoplasma antibody detection in patients with culture-confirmed histoplasmosis at Mayo Clinic (Rochester, MN) over a 10-year period (2011 to 2020).

Abstract Background Gram-negative bacteremia (GNB) as a manifestation of cardiovascular implantable electronic device (CIED) infection is uncommon. Moreover, echocardiography may be nonspecific in its ability to differentiate whether CIED lead masses are infected. We aimed to determine the rate of CIED infection in the setting of GNB. Methods All patients with CIED who were hospitalized with GNB during 2012–2019 at Mayo Clinic were investigated. The definition of CIED infection was based on criteria recommended by the 2019 European Heart Rhythm Association document. Results A total of 126 patients with CIED developed GNB. None of them had signs of pocket infection. Twenty (15.9%) patients underwent transesophageal echocardiography. Overall, 4 (3%) patients had definite CIED infection. None of them underwent CIED extraction; 3 died within 12 weeks and 1 received long-term antibiotic suppression. Ten (8%) patients had possible CIED infection; despite no CIED extraction, no patient had relapsing GNB. We observed a higher rate of CIED infection in patients with Serratia marcescens bacteremia as compared to that in patients with other GNB. Conclusions The rate of CIED infection following GNB was relatively low. However, accurate classification of CIED infection among patients presenting with GNB remains challenging, in part, due to a case definition of CIED infection that is characterized by a low pretest probability in the setting of GNB. Prospective, multicenter studies are needed to determine accurate identification of CIED infection among GNB, so that only patients with true infection undergo device removal.

Most gene-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are nonreplicating vectors. They deliver the gene or messenger RNA to the cell to express the spike protein but do not replicate to amplify antigen production. This study tested the utility of replication in a vaccine by comparing replication-defective adenovirus (RD-Ad) and replicating single-cycle adenovirus (SC-Ad) vaccines that express the SARS-CoV-2 spike protein. SC-Ad produced 100 times more spike protein than RD-Ad and generated significantly higher antibodies against the spike protein than RD-Ad after single immunization of Ad-permissive hamsters. SC-Ad–generated antibodies climbed over 14 weeks after single immunization and persisted for more than 10 months. When the hamsters were challenged 10.5 months after single immunization, a single intranasal or intramuscular immunization with SC-Ad-Spike reduced SARS-CoV-2 viral loads and damage in the lungs and preserved body weight better than vaccination with RD-Ad-Spike. This demonstrates the utility of harnessing replication in vaccines to amplify protection against infectious diseases.