Broad-spectrum Therapy Research Articles

A Survey of Inhibitors for the Main Protease of Coronaviruses with the Potential for Development of Broad-Spectrum Therapeutics

The coronaviruses plaguing humanity in the 21st century share much in common: a spontaneous route of origin from wild animals, a propensity to take human life, and, importantly, a highly conserved set of biological machinery necessary for viral replication. Most recently, the SARS-CoV-2 is decimating economies around the world and has claimed over two million human lives, reminding the world of a need for an effective drug against present and future coronaviruses. To date, attempts to repurpose clinically approved antiviral medications show minimal promise, highlighting the need for development of new antiviral drugs. Nucleotide analog inhibitors are a promising therapeutic candidate, but early data from clinical studies suggests these compounds have limited efficacy. However, novel compounds targeting the main protease responsible for critical steps in viral assembly are gaining considerable interest because they offer the potential for broad-spectrum coronavirus therapy. Here, we review the literature regarding potential inhibitors for the main protease of coronaviruses, especially SARS-CoV-2, analyze receptor-drug interactions, and draw conclusions about candidate inhibitors for future outbreaks. Promising candidates for development of a broad-spectrum coronavirus protease inhibitor include the neuraminidase inhibitor 3K, the peptidomimetic inhibitor 11a and 11b, the α-ketoamide inhibitor 13b, the aldehyde prodrug, and the phosphate prodrug developed by Pfizer. In silico and in vitro analyses have shown that these inhibitors strongly interact with the active site of the main protease, and to varying degrees, prevent viral replication via interactions with the largely conserved active site pockets. KEYWORDS: Severe Acute Respiratory Syndrome Coronavirus; Middle East Respiratory Syndrome Coronavirus; Severe Acute Respiratory Syndrome Coronavirus 2; Replicase Polypeptide; Protease; Neuraminidase Inhibitor; Peptidomimetic Inhibitor; α-Ketoamide Inhibitor; Molecular Docking

#100: Disseminated Toxoplasmosis Presenting as Persistent Fevers in a Hematopoietic Stem Cell Transplant Recipient

Abstract Background Toxoplasma reactivation is a known concern in hematopoietic stem cell transplant (HSCT) patients with high mortality of approximately 40% and up to 100% if left untreated. The risk is highest when patients are most immunocompromised and presentation can vary from isolated fever to disseminated disease with CNS toxoplasmosis, pneumonitis, and myocarditis. Case The patient is a 10-year-old male with acute promyelocytic leukemia (APML) CNS1 status post-chemotherapy, secondary acute myeloid leukemia (AML), now status post 10/10 matched unrelated donor hematopoietic stem cell transplant (HSCT). He initially developed fever and neutropenia during conditioning chemotherapy with resolved fever prior to stem cell transplant. His transplant course was complicated by grade IV mucositis on day +4 with improvement on day +11. On day +19 he developed new fevers (Tmax 40.5oC) with a negative initial workup. He continued to have persistent fevers on broad-spectrum empiric therapy with meropenem and liposomal amphotericin B and also complained of daily headaches and abdominal pain, with worsening diffuse body pain. On day +26 the Pediatric Infectious Diseases team was consulted as a CT Chest demonstrated small scattered ground glass nodules in the right lung with minimal bibasilar atelectasis and small pleural effusions. Upon chart review, he was noted to be Toxoplasma IgG positive prior to transplant. Further infectious diseases studies were sent to evaluate for fungal etiologies, including a Toxoplasma PCR blood, and given persistent fever, he was empirically started on trimethoprim–sulfamethoxazole (TMP-SMX) by the primary team. Shortly after the initiation of TMP-SMX he became afebrile and testing confirmed Toxoplasma reactivation with positive PCR studies from the blood, cerebrospinal fluid (CSF), bronchoalveolar lavage (BAL), and bone marrow. He was treated with pyrimethamine, sulfadiazine, and folinic acid and developed sulfa crystalluria, requiring alteration of his therapy. He received multiple treatment regimens and continued on maintenance therapy without further complications. Conclusion This case highlights the importance of serial surveillance or empiric prophylaxis for Toxoplasma reactivation in HSCT recipients known to have prior infection. There is high associated mortality and patients may present with isolated fever or severe disseminated disease with multi-organ involvement. Toxoplasma disease requires the presence of organ involvement as demonstrated in our patient and treatment is typically 6 weeks at higher doses followed by maintenance therapy. The definite treatment course varies by clinical response and multiple options are available if toxicities occur.

Antibacterial Photodynamic Gold Nanoparticles for Skin Infection.

Damage or injury to the skin creates wounds that are vulnerable to bacterial infection, which in turn retards the process of skin regeneration and wound healing. In patients with severe burns and those with chronic diseases, such as diabetes, skin infection by multidrug-resistant bacteria can be lethal. Therefore, a broad-spectrum therapy to effectively eradicate bacterial infection through a mechanism different from that of antibiotics is much sought after. We successfully synthesized antibacterial photodynamic gold nanoparticles (AP-AuNPs), which are self-assembled nanocomposites of an antibacterial photodynamic peptide and poly(ethylene glycol) (PEG)-stabilized AuNPs. The AP-AuNPs exhibited aqueous and light stability, a satisfactory generation of reactive oxygen species (ROS), and a remarkable antibacterial effect toward both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli upon light irradiation. Moreover, the synthesized nanocomposites significantly inhibited bacterial growth and biofilm formation in vitro. Photodynamic antibacterial treatment accelerated the wound-healing rate in S. aureus infections, mimicking staphylococcal skin infections. Using a combination of the bactericidal effect of a peptide, the photodynamic effect of a photosensitizer, and the multivalency clustering on AuNPs for maximal antibacterial effect under light irradiation, we synthesized AP-AuNPs as a wound-dressing nanomaterial in skin infections to promote wound healing. Our findings indicate a promising strategy in the management of bacterial infections resulting from damaged skin tissue, an aspect that has not been fully explored by our peers.

Selective reaction of conjugated polymers with basic proteins for broad-spectrum antivirulence therapy

Antivirulence therapy has proven to be an attractive method for the treatment of bacterial infections and venomous injuries; however, the approaches for neutralizing multiple types of virulence through one platform are limited. To address this challenge, we have developed a reactive conjugated polymer, PPV–NHS, which functions as a broad-spectrum antidote for directly inactivating basic toxins. The antivirulence is achieved via multivalent electrostatic recognition and subsequent amidation reactions between PPV–NHS and toxins. The resultant bioconjugates significantly reduced neurotoxicity and cytotoxicity. In the mouse model, PPV–NHS effectively inhibited the toxicity of cardiotoxin (CTX) and improved the survival rate of toxin-challenged mice. This work represents the rational design of functionalized conjugated polymers for antivirulence therapy with both high efficiency and broad applicability.

Tailored liposomal nanotraps for the treatment of Streptococcal infections

BackgroundStreptococcal infections are associated with life-threatening pneumonia and sepsis. The rise in antibiotic resistance calls for novel approaches to treat bacterial diseases. Anti-virulence strategies promote a natural way of pathogen clearance by eliminating the advantage provided to bacteria by their virulence factors. In contrast to antibiotics, anti-virulence agents are less likely to exert selective evolutionary pressure, which is a prerequisite for the development of drug resistance. As part of their virulence mechanism, many bacterial pathogens secrete cytolytic exotoxins (hemolysins) that destroy the host cell by destabilizing their plasma membrane. Liposomal nanotraps, mimicking plasmalemmal structures of host cells that are specifically targeted by bacterial toxins are being developed in order to neutralize-by competitive sequestration-numerous exotoxins.ResultsIn this study, the liposomal nanotrap technology is further developed to simultaneously neutralize the whole palette of cytolysins produced by Streptococcus pneumoniae, Streptococcus pyogenes and Streptococcus dysgalactiae subspecies equisimilis-pathogens that can cause life-threatening streptococcal toxic shock syndrome. We show that the mixture of liposomes containing high amounts of cholesterol and liposomes composed exclusively of choline-containing phospholipids is fully protective against the combined action of exotoxins secreted by these pathogens.ConclusionsUnravelling the universal mechanisms that define targeting of host cells by streptococcal cytolysins paves the way for a broad-spectrum anti-toxin therapy that can be applied without a diagnostic delay for the treatment of bacterial infections including those caused by antibiotic-resistant pathogens.

Sexually Transmitted Neisseria gonorrhoeae Infections-Update on Drug Treatment and Vaccine Development.

Background: Sexually transmitted gonorrhea, caused by the Gram-negative diplococcus Neisseria gonorrhoeae, continues to be a serious global health challenge despite efforts to eradicate it. Multidrug resistance among clinical N. gonorrhoeae isolates has limited treatment options, and attempts to develop vaccines have not been successful. Methods: A search of published literature was conducted, and information extracted to provide an update on the status of therapeutics and vaccine development for gonorrheal infection. Results: Recommended pharmacological treatment for gonorrhea has changed multiple times due to increasing acquisition of resistance to existing antibiotics by N. gonorrhoeae. Only broad-spectrum cephalosporin-based combination therapies are currently recommended for treatment of uncomplicated urogenital and anorectal gonococcal infections. With the reported emergence of ceftriaxone resistance, successful strategies addressing the global burden of gonorrhea must include vaccination. Century-old efforts at developing an effective vaccine against gonorrhea, leading to only four clinical trials, have not yielded any successful vaccine. Conclusions: While it is important to continue to explore new drugs for the treatment of gonorrhea, the historical trend of resistance acquisition suggests that any long-term strategy should include vaccine development. Advanced technologies in proteomics and in silico approaches to vaccine target identification may provide templates for future success.

Secondary Hemophagocytic Lymphohistiocytosis in a Young Hispanic Adult

Hemophagocytic lymphohistiocytosis (HLH) is a disease caused by a severe immune system reaction that involves an overwhelming inflammatory response with overproduction of cytokines and hemophagocytosis. HLH is classified as primary HLH or familial HLH (PHLH or FHLH) and secondary HLH. PHLH is due to mutations in several genes that regulate immune cells, while secondary HLH is triggered by a severe illness (viral infections or malignancies) that induce an excessive immune response that is difficult to control. We present a case of a young Hispanic adult female with a medical history of diabetes mellitus type 1 and hepatitis E that was diagnosed with HLH secondary to lymphoma caused by Epstein Barr virus infection. The patient was started on broad-spectrum antibiotics and steroid therapy; however, the patient succumbed to the disease. HLH is associated with high mortality, mainly because it is not a very common entity and patients usually present critically ill and deteriorate very fast. Immunosuppression and treatment of the underlying disorder is the target of the treatment of HLH, however, the prognosis remains poor.

Bioinspired Spiky Peroxidase-Mimics for Localized Bacterial Capture and Synergistic Catalytic Sterilization.

Besides the pandemic caused by the coronavirus outbreak, many other pathogenic microbes also pose a devastating threat to human health, for instance, pathogenic bacteria. Due to the lack of broad-spectrum antibiotics, it is urgent to develop nonantibiotic strategies to fight bacteria. Herein, inspired by the localized "capture and killing" action of bacteriophages, a virus-like peroxidase-mimic (V-POD-M) is synthesized for efficient bacterial capture (mesoporous spiky structures) and synergistic catalytic sterilization (metal-organic-framework-derived catalytic core). Experimental and theoretical calculations show that the active compound, MoO3 , can serve as a peroxo-complex-intermediate to reduce the free energy for catalyzing H2 O2 , which mainly benefits the generation of •OH radicals. The unique virus-like spikes endow the V-POD-M with fast bacterial capture and killing abilities (nearly 100% at 16 µg mL-1 ). Furthermore, the in vivo experiments show that V-POD-M possesses similar disinfection treatment and wound skin recovery efficiencies to vancomycin. It is suggested that this inexpensive, durable, and highly reactive oxygen species (ROS) catalytic active V-POD-M provides a promising broad-spectrum therapy for nonantibiotic disinfection.

Bacterial Infection among Cancer Patients: Analysis of Isolates and Antibiotic Sensitivity Pattern.

Introduction Cancer patients being immunosuppressed are vulnerable to develop infections. Knowledge of the changing epidemiology of infections has a pivotal role in its management. Aims and Objectives. The study is undertaken to assess the types of bacterial infections in cancer patients undergoing anticancer treatment, the associated bacterial pathogens, and their antibiotic sensitivity patterns. Materials and Methods A retrospective surveillance study was undertaken in our center. Positive culture reports and other clinical details of cancer patients diagnosed with infection during a stay in the tertiary care center from 1st January 2015 to 31st December 2016 were analysed by descriptive statistical methods chi-square test and odds ratio to study the association. Results Out of 638 cancer patients diagnosed with infections in the 2-year period, 140 patients had positive cultures, representing 272 specimens and 306 isolates. Common specimens sent for culture were blood sputum, urine, and pus. 214 isolates (69.9%) were gram-negative bacilli, and 92 (30.1%) were gram-positive cocci. The most common isolates were Klebsiella spp. (18.30%), Pseudomonas spp. (17.65%), and Escherichia coli (14.71%) followed by Staphylococcus aureus (13.72%). Among the gram-negative organisms, the antibiotic resistance rates reported to fluoroquinolones, aminoglycosides, and third-generation cephalosporins were 45.13%, 39.20%, and 48.58%, respectively. 26.92% of the organisms are resistant to all three antibiotics. 50.4% of Klebsiella spp. and Escherichia coli were ESBL producers. Gram-negative organisms showed 11.63% resistance to β-lactam/β-lactamase inhibitor combination, and 22.22% of gram-negative organisms are resistant to carbapenems. 50% of the Staphylococcus spp. were methicillin resistant, but all were sensitive to vancomycin. Conclusion The surge in the number of gram-negative infections emphasizes the need for broad-spectrum empirical therapy targeting the same. Rate of resistance of the isolated gram-negative organisms to the routinely used empirical therapy is alarming. Prudent use of antibiotics, based on culture reports wherever possible, is of utmost importance to save the lives of infected patients and prevent further development of antibiotic resistance.

Comparative analysis of the effectiveness of narrow-spectrum versus broad-spectrum antibiotics for the treatment of childhood pneumonia.

Objectives:The main objective of this study was to compare the effectiveness of empiric treatment with narrow-spectrum therapy versus broad-spectrum therapy for children hospitalized with community-acquired pneumonia (CAP) at the University of Gondar Referral Hospital, Gondar, Ethiopia.Methods:Institutional-based retrospective chart review was conducted at the University of Gondar Referral Hospital (GURH) pediatrics ward from 1 February 2016 to 30 April 2016. The collected data were entered and analyzed using Statistical Package for Social Sciences (SPSS) version 20. Descriptive statistics were done to present the basic features and summary of the data set. In addition, binary logistics and multivariable logistic regression analysis were conducted to test for an association between the dependent and independent variables. A P value of <0.05 was taken to declare statistical significance at a 95% confidence interval.Result:A total of 147 patients with CAP were included in the study. Seven different treatment regimens were employed for the 147 children hospitalized. About 63 (42.9%) of the study participants received a narrow-spectrum antibiotic and 84 (57.1%) received a broad-spectrum antibiotic. There was no significant difference between the broad and narrow spectrum treatment groups in main treatment outcomes. The median length of stay (LOS) for the study population was 3 days. The median LOS was shorter among those receiving narrow-spectrum therapy compared with those receiving broad-spectrum therapy. Treatment dose and duration of therapy were significantly associated with treatment outcome (P < 0.0001 and P = 0.003), respectively.Conclusion:The effectiveness of narrow-spectrum therapy is similar to that of broad-spectrum therapy for children hospitalized with CAP. Treatment regimens for children with community-acquired pneumonia should be selected based on their safety profile and their tendency for antibiotic resistance.

192. A Hematology/Oncology Unit-Specific Antibiogram Emphasizes the Need for Intensified Local Stewardship

BackgroundAntibiograms are important stewardship tools for empiric antibiotic prescribing. Appropriate therapy is particularly important in patients with hematologic malignancies and bone marrow transplants being treated for febrile neutropenia. These patients are at high risk for multi-drug resistance based on extensive prior antibiotic and hospital exposures, and therefore, hospital-wide antibiograms may not reliably reflect resistance patterns for this population. We created a unit-specific antibiogram for a closed hematology/oncology unit and hypothesized there would be decreased antibiotic susceptibilities compared to the hospital-wide antibiogram.MethodsAll positive cultures with antimicrobial susceptibilities on a closed 32-bed hematology-oncology unit from 7/2016-6/2019 were obtained from the microbiology laboratory. Based on recommendations by the Clinical and Laboratory Standards Institute (CLSI), only organisms with > 30 isolates were included in antibiogram analysis. Susceptibilities were compared to those reported in our hospital-wide antibiograms from the same time period using Fisher’s exact test.ResultsTwo organisms met CLSI criteria: Escherichia coli (n=83) and Klebsiella pneumoniae (n=31). Unit Escherichia coli isolates were significantly more resistant to almost all commonly tested antibiotics (Table 1). Klebsiella pneumoniae unit susceptibilities were significantly lower for many antibiotics, including aztreonam, ceftriaxone, cefepime, levofloxacin, piperacillin-tazobactam and tobramycin (Table 1).Table 1: Percentage of Escherichia coli and Klebsiella pneumoniae isolates susceptible to reported antibiotic agents ConclusionOur hematology-oncology antibiogram showed significantly lower antibiotic susceptibilities in Escherichia Coli and Klebsiella pneumoniae compared with the hospital-wide antibiogram. These findings can help guide prescribers toward appropriate broad-spectrum empiric therapy. Additionally, results suggest a need for intensified stewardship measures to prevent multi-drug resistance in this population.Disclosures All Authors: No reported disclosures

1339. Antibiotic Prescribing Varies among Patients with a Documented Penicillin or Cephalosporin Adverse Drug Reaction

BackgroundStudies have shown that over half of hospitalized children receive an antibiotic during their encounter, of which between 30-50% is considered inappropriate. Antibiotic prescribing is further complicated as approximately 10% of children are labeled beta-lactam allergic, resulting in the use of either broad-spectrum or suboptimal therapy. The purpose of this study was to compare antibiotic prescribing between patients with a documented ADR vs. those without using a nationwide sample of hospitalized children.MethodsWe performed a point prevalence study among 32 hospitals between July 2016-December 2017 where data were collected via chart review on pediatric patient and antimicrobial characteristics, including the indication for all antimicrobials. In additional, ADR history data were collected on which antimicrobial(s) were documented (e.g., penicillin, cephalosporins). Patients were mutually assigned into either: 1) no documented ADR; 2) penicillin ADR-only; 3) cephalosporin ADR-only; and 4) ADR for both penicillin and cephalosporin. The distribution of antibiotics were compared between the ADR groups, stratified by the indication for treatment.ResultsA total of 12,250 pediatric patients (17,929 antibiotic orders) who were actively receiving antibiotics were identified. A history of penicillin and cephalosporin ADR was documented in 5.5% and 2.8% of these patients, respectively. When compared to patients with no documented ADR, penicillin ADR patients were more likely to receive a fluoroquinolone for a SSTI infection (odds ratio [OR]: 5.6), surgical prophylaxis (OR: 18.8) or for surgical treatment (OR: 5.2) (see Figure). Conversely, penicillin ADR patients were less likely to receive first-line agents, such as narrow-spectrum penicillin for bacterial LRTI (OR: 0.08) and piperacillin/tazobactam for GI infections (OR: 0.22). Cephalosporin ADR patients exhibited similar patterns with increased use of carbapenems and fluoroquinolones when compared to patients with no ADR.Figure 1: Odds of Receiving Select Antimicrobials Among PCN ADR Patients When Compared to Non-ADR patients, by Indication ConclusionA large, nationwide sample of pediatric patients who were actively prescribed antibiotics helped identify several diagnoses where comprehensive guidelines for appropriate ADR prescribing and increased ADR de-labeling initiatives are needed to ensure optimal treatment.Disclosures Brian R. Lee, MPH, PhD, Merck (Grant/Research Support) Jason Newland, MD, MEd, FPIDS, Merck (Grant/Research Support)Pfizer (Other Financial or Material Support, Industry funded clinical trial)

1477. Impact Of Resistance Thresholds On Mortality In Hospital-Acquired And Ventilator-Associated Pneumonia

BackgroundHospital-acquired (HAP) and ventilator-associated pneumonia (VAP) represent a significant source of morbidity and mortality in hospitalized patients. Numerous studies demonstrate mortality benefit with appropriate empiric therapy. Choosing the right empiric coverage is paramount; however, this decision becomes more challenging as rates of antibiotic resistance rise. Most recent HAP/VAP guidelines use an arbitrary population resistance rate of 20% to recommended methicillin-resistant Staphylococcus aureus (MRSA) coverage and double-coverage of resistant gram negative bacilli (GNB). Using this threshold has led to overuse of broad spectrum antimicrobials. The goal of this study is to mathematically explore the impact of this threshold on patient outcomes and link population resistance rates to individual mortality risk.MethodsWe used the concept of excess morality risk (EMR) to develop a theoretical simulation model based for HAP/VAP caused by GNB and MRSA empirically treated with piperacillin-tazobactam and vancomycin. EMR is the product of the proportion of HAP/VAP caused by GNB/MRSA, the rate of antibiotic (piperacillin-tazobactam/ methicillin) resistance in GNB and Staphylococcus aureus isolates and the difference in mortality between discordant and appropriate antibiotic therapy. Model parameters were obtained from large surveillance networks and published clinical trials.ResultsAt the HAP/VAP guideline threshold of 20% methicillin resistance in SA isolates, the EMR was 0.3%; when the model included only culture positive patients, EMR was 0.6%. At a threshold of 20% resistance to piperacillin-tazobactam in GNB isolates, EMR was 1.9% and 3.1% when culture-negative patients were excluded. EMR increased as baseline risk of failure with discordant therapy increased (e.g. critically ill patients, ventilated HAP).Risk Difference of Death for Staphylococcus aureus Isolates Risk Difference of Death for Gram Negative Bacilli ConclusionThis model offers a mathematical exploration of the individual excess risk for death in patients with HAP/VAP caused by GNB/MRSA because of discordant therapy. The objectivity of the model would better allow clinicians, guideline authors, and health policy makers to weigh excess risk versus possible harms of broad-spectrum therapy when developing population resistance thresholds cutoffs for empiric therapy recommendations.Disclosures All Authors: No reported disclosures

Antibiotic utilization variability among training services at an academic medical center: An observational study.

Evaluate the difference in antibiotic prescribing between various levels of resident training or attending types. Observational, retrospective study. Tertiary-care, academic medical center in Madison, Wisconsin. We measured antibiotic utilization from January 1, 2016, through December 31, 2018, in our general medicine (GM) and hospitalist services. The GM1 service is staffed by outpatient internal medicine physicians, the GM2 service is staffed by geriatricians and hospitalists, and the GM3 service is staffed by only hospitalists. The GMA service is led by junior resident physicians, and the GMB service is led by senior resident physicians. We measured utilization using days of therapy (DOT) per 1,000 patient days (PD). In a secondary analysis based on antibiotic spectrum, we used average DOT per 1,000 PD. Teaching services prescribed more antibiotics than nonteaching services (671.6 vs 575.2 DOT per 1,000 PD; P < .0001). Junior resident-led services used more antibiotics than senior resident-led services (740.9 vs 510.0 DOT per 1,000 PD; P < .0001). Overall, antibiotic prescribing was numerically similar between various attending physician backgrounds. A secondary analysis showed that GM services prescribed more broad-spectrum, anti-MRSA, and anti-pseudomonal antibiotics than the hospitalist services. GM junior resident-led services prescribed more broad-spectrum, anti-MRSA, and antipseudomonal therapy compared to their senior counterparts. Antibiotics were prescribed at a significantly higher rate in services associated with trainees than those without. Services led by a junior resident physician prescribed antibiotics at a significantly higher rate than services led by a senior resident. Interventions to reduce unnecessary antibiotic exposure should be targeted toward resident physicians, especially junior trainees.

A mould infection in disguise

A female was admitted to our hospital with a penetrating abdominal lesion. A foreign body was removed surgically from the abdominal cavity. She developed severe sepsis necessitating repeated surgical explorations of the abdomen. Despite these surgical interventions and initiation of broad-spectrum antibacterial therapy septic shock developed. A blood culture became positive, showing a yeast-like cell with a germ tube in the Gram stain (Fig. 1a). The same day stool cultures became positive with the mould Lomentospora prolificans.

Concomitant Immunosuppressive Therapy Use in Eculizumab-Treated Adults With Generalized Myasthenia Gravis During the REGAIN Open-Label Extension Study.

Introduction: Chronic, broad-spectrum immunosuppressive therapy (IST) can be associated with side effects in many people with generalized myasthenia gravis (gMG), and treatment guidelines recommend that the IST dose be tapered once patients achieve a stable treatment response. We therefore examined IST use in eculizumab-treated patients with refractory gMG.Methods: The REGAIN open-label extension (OLE) enrolled 117 adults with refractory anti-acetylcholine receptor antibody-positive gMG who had completed the 6-month, randomized, double-blind, placebo-controlled REGAIN study of eculizumab. Eligible patients had received ≥2 ISTs for ≥1 year or ≥1 IST with intravenous immunoglobulin or plasma exchange ≥4 times in 1 year, without symptom control. During REGAIN, changes in concomitant MG therapies were not permitted; during the OLE, they were permitted at the investigators' discretion. Participants received eculizumab 1,200 mg every 2 weeks for up to 4 years; concomitant prednisone and related corticosteroids (PRED), azathioprine (AZA), and mycophenolate mofetil (MMF) use was recorded. Changes in MG Activities of Daily Living and Quantitative MG total scores, MG exacerbations, and adverse events were also recorded.Results: At last OLE assessment, 88.0% (103/117) of participants were using ≥1 IST vs. 98.3% (115/117) at OLE baseline. During the OLE, 76.9% (90/117) of patients experienced a total of 719 IST changes. Almost half of participants [48.7% (57/117)] stopped or decreased ≥1 IST owing to MG symptom improvement, representing 38.9% (280/719) of all changes. In patients who decreased and/or stopped ≥1 IST, mean daily doses of PRED, AZA, and MMF decreased between OLE baseline and last assessment by 60.8% [standard deviation (SD), 28.07; P < 0.0001], 89.1% (SD, 25.77; P < 0.0001), and 56.0% (SD, 32.99; P < 0.0001), respectively. Improved clinical outcomes were observed with eculizumab regardless of IST changes during the OLE, and eculizumab's safety profile was similar in patients who used PRED, AZA, and MMF.Conclusions: Use of ISTs by patients with previously refractory gMG decreased during eculizumab treatment in the REGAIN OLE. Clinical improvements with eculizumab were maintained by patients in all groups, including those who decreased and/or stopped concomitant ISTs.Trial registration: www.clinicaltrials.gov: NCT01997229, NCT02301624.

Anticipatory Stress Responses and Immune Evasion in Fungal Pathogens.

In certain niches, microbes encounter environmental challenges that are temporally linked. In such cases, microbial fitness is enhanced by the evolution of anticipatory responses where the initial challenge simultaneously activates pre-emptive protection against the second impending challenge. The accumulation of anticipatory responses in domesticated yeasts, which have been termed 'adaptive prediction', has led to the emergence of 'core stress responses' that provide stress cross-protection. Protective anticipatory responses also seem to be common in fungal pathogens of humans. These responses reflect the selective pressures that these fungi have faced relatively recently in their evolutionary history. Consequently, some pathogens have evolved 'core environmental responses' which exploit host signals to trigger immune evasion strategies that protect them against imminent immune attack.

Time for pragmatic, prospective clinical trials to determine the role of empirical antibacterial therapy in critically ill adults hospitalized with malaria

BackgroundChildren with severe falciparum malaria in malaria-endemic regions are predisposed to developing life-threatening bacterial co-infection. International guidelines therefore recommend empirical broad-spectrum antibacterial therapy in these children. Few studies have examined co-infection in adults, although it has been believed to be relatively rare; antibacterial therapy is therefore not routinely recommended in adults with falciparum malaria. DiscussionHowever, the fundamental pathophysiology of falciparum malaria in adults and children is the same; it is therefore unclear why adults would not also be predisposed to bacterial infection. Indeed, recent studies have identified bacteraemia in >10% of adults hospitalized with malaria. Some have suggested that these adults probably had bacterial sepsis, with the parasitaemia an incidental finding. However, it is usually impossible in resource-limited settings to determine–at presentation–whether critically ill, parasitaemic adults have severe malaria, bacterial sepsis, or both. Given the significant case-fatality rates of severe malaria and bacterial sepsis, the pragmatic initial approach would be to cover both possibilities. ConclusionsLife-threatening bacterial co-infection may be more common in critically ill adults with malaria than previously believed. While further prospective data are awaited to confirm these findings, it might be more appropriate to provide empirical aantibacterial cover in these patients than current guidelines suggest.

Effects of Susceptibility Result Suppression on National Healthcare Safety Network Antibiotic Resistance Option Data

Background: The National Healthcare Safety Network’s (NHSN) Antibiotic Resistance (AR) Option offers hospitals a way to report antibiotic resistance data from their facility’s laboratory information system and create facility-specific antibiograms. Suppression of select antibiotic susceptibility results may be used by antibiotic stewardship teams to prevent unnecessary use of broad-spectrum therapies by not making those susceptibilities available to providers. To be of use, antibiograms should offer a complete picture of antibiotic resistance. We wanted to understand the impact of data suppression. Methods: A retrospective cross-sectional study was conducted including data from 2017 and 2018. The clinical susceptibility data for cefotaxime, ceftriaxone, ceftazidime, ertapenem, imipenem, and meropenem against carbapenem-resistant Enterobacteriaceae (CRE), Pseudomonas aeruginosa (CRPA), Acinetobacter baumannii (CRAB), and extended-spectrum β-lactamase–producing Enterobacteriaceae (ESBL) were collected from commercial antimicrobial susceptibility testing instruments (cASTI) in 3 Tennessee healthcare networks that also report to the NHSN AR Option. These data were linked to the NHSN data using 4 keys: date of birth, isolate collection date, pathogen, and specimen source. An isolate was defined as suppressed when susceptibility results were observed from the cASTI but not in NHSN. The proportions of suppressed results were calculated and stratified by genus, facility, and antibiotic. Results: Overall, 1,009 isolates were matched between the NHSN AR data and the laboratory test results. Of these, 4.1% were CRAB, 23.3% were CRPA, and 72.6% were Enterobacteriaceae. In total, 4,948 susceptibility results were available from cASTIs. Suppressed results in NHSN data were observed in 918 isolates (91.0%) and accounted for 2,797 results (56.6%). Of the 817 isolates tested against imipenem, 18.7% were found to be suppressed. Moreover, 100%, 57.9%, and 8.6% of imipenem tests against CRAB, CRPA, and Enterobacteriaceae, respectively, were suppressed. Of the suppressed results, 38.3%, 3.6%, and 58.1% were susceptible, intermediate, and resistant respectively. Of the 363 isolates tested against meropenem, 48.2% were found to be suppressed. In addition, 12.2%, 53.0%, and 52.2% of meropenem tests against CRAB, CRPA, and Enterobacteriaceae, respectively, were suppressed. Of the suppressed results, 47.4%, 11.4%, and 41.1% were susceptible, intermediate, and resistant, respectively. Conclusions: A large proportion of isolates had at least 1 analyzed antibiotic suppressed within the NHSN AR Option. It will be important to develop and implement strategies to ensure that nonsuppressed data are available to be reported to the NHSN AR module.Funding: NoneDisclosures: None

Neutralizing Effects of Small Molecule Inhibitors and Metal Chelators on Coagulopathic Viperinae Snake Venom Toxins.

Animal-derived antivenoms are the only specific therapies currently available for the treatment of snake envenoming, but these products have a number of limitations associated with their efficacy, safety and affordability for use in tropical snakebite victims. Small molecule drugs and drug candidates are regarded as promising alternatives for filling the critical therapeutic gap between snake envenoming and effective treatment. In this study, by using an advanced analytical technique that combines chromatography, mass spectrometry and bioassaying, we investigated the effect of several small molecule inhibitors that target phospholipase A2 (varespladib) and snake venom metalloproteinase (marimastat, dimercaprol and DMPS) toxin families on inhibiting the activities of coagulopathic toxins found in Viperinae snake venoms. The venoms of Echis carinatus, Echis ocellatus, Daboia russelii and Bitis arietans, which are known for their potent haemotoxicities, were fractionated in high resolution onto 384-well plates using liquid chromatography followed by coagulopathic bioassaying of the obtained fractions. Bioassay activities were correlated to parallel recorded mass spectrometric and proteomics data to assign the venom toxins responsible for coagulopathic activity and assess which of these toxins could be neutralized by the inhibitors under investigation. Our results showed that the phospholipase A2-inhibitor varespladib neutralized the vast majority of anticoagulation activities found across all of the tested snake venoms. Of the snake venom metalloproteinase inhibitors, marimastat demonstrated impressive neutralization of the procoagulation activities detected in all of the tested venoms, whereas dimercaprol and DMPS could only partially neutralize these activities at the doses tested. Our results provide additional support for the concept that combinations of small molecules, particularly the combination of varespladib with marimastat, serve as a drug-repurposing opportunity to develop new broad-spectrum inhibitor-based therapies for snakebite envenoming.