Streptococcus canis Native Aortic Valve Endocarditis Linked to Cat Exposure: A Case Report and Review.

Streptococcus canis is an uncommon human pathogen, but documented infections have been mostly associated with exposure to dogs. There are only five documented cases of endocarditis secondary to streptococcus canis, with all cases except one documenting exposure to a canine. We present a 74-year-old male with a history of Type 2 diabetes mellitus, CKD 3, moderate aortic stenosis and remote exposure to agent orange, who was found to have Streptococcus canis native valve endocarditis without exposure to a dog. To the best of our knowledge this case is the first case of endocarditis linked to feline exposure.

Selection of a promiscuous minimalist cAMP phosphodiesterase from a library of de novo designed proteins.

The ability of unevolved amino acid sequences to become biological catalysts was key to the emergence of life on Earth. However, billions of years of evolution separate complex modern enzymes from their simpler early ancestors. To probe how unevolved sequences can develop new functions, we use ultrahigh-throughput droplet microfluidics to screen for phosphoesterase activity amidst a library of more than one million sequences based on a de novo designed 4-helix bundle. Characterization of hits revealed that acquisition of function involved a large jump in sequence space enriching for truncations that removed >40% of the protein chain. Biophysical characterization of a catalytically active truncated protein revealed that it dimerizes into an α-helical structure, with the gain of function accompanied by increased structural dynamics. The identified phosphodiesterase is a manganese-dependent metalloenzyme that hydrolyses a range of phosphodiesters. It is most active towards cyclic AMP, with a rate acceleration of ~109 and a catalytic proficiency of >1014 M-1, comparable to larger enzymes shaped by billions of years of evolution.

Efficacy of bezlotoxumab to prevent recurrent Clostridioides difficile infection (CDI) in patients with multiple prior recurrent CDI.

Among 23 patients with multiply recurrent Clostridioides difficile infection (mrCDI) who received bezlotoxumab at the end of antibiotic treatment a sustained clinical response of 91 % at 30 days and 78 % at 90 days was achieved. Bezlotoxumab administered at the end of antibiotic treatment was effective in patients with mrCDI.

Clinical Characteristics of the 2019 Eastern Equine Encephalitis Outbreak in Michigan.

Background: Eastern equine encephalitis virus is a mosquito-borne alphavirus responsible for unpredictable outbreaks of severe neurologic disease in animals and humans. While most human infections are asymptomatic or clinically nonspecific, a minority of patients develops encephalitic disease, a devastating illness with a mortality rate of ≥30%. No treatments are known to be effective. Eastern equine encephalitis virus infection is rare in the United States, with an annual average nationwide incidence of 7 cases between 2009 and 2018. However, in 2019, 38 cases were confirmed nationwide, including 10 in Michigan. Methods: Data from 8 cases identified by a regional network of physicians in southwest Michigan were abstracted from clinical records. Clinical imaging and histopathology were aggregated and reviewed. Results: Patients were predominantly older adults (median age, 64 years), and all were male. Results of initial arboviral cerebrospinal fluid serology were frequently negative, and diagnosis was not made until a median of 24.5 days (range, 13-38 days) after presentation, despite prompt lumbar punctures in all patients. Imaging findings were dynamic and heterogeneous, with abnormalities of the thalamus and/or basal ganglia, and prominent pons and midbrain abnormalities were displayed in 1 patient. Six patients died, 1 survived the acute illness with severe neurologic sequelae, and 1 recovered with mild sequelae. A limited postmortem examination revealed diffuse meningoencephalitis, neuronophagia, and focal vascular necrosis. Conclusions: Eastern equine encephalitis is a frequently fatal condition whose diagnosis is often delayed, and for which no effective treatments are known. Improved diagnostics are needed to facilitate patient care and encourage the development of treatments.

Recurrence of Disseminated Mycobacterium avium intracellulare Presenting as Spondylodiscitis and Epidural Abscess in a Patient with Acquired Immune Deficiency Syndrome (AIDS).

BACKGROUND Mycobacterium avium intracellulare complex (MAI) is a member of the non-tuberculous mycobacteria family, which can cause both pulmonary and non-pulmonary disease. In patients with advanced HIV, it is known to cause disseminated disease. We present a case of a 65-year-old man who has sex with men (MSM) with AIDS, found to have spondylodiscitis and an epidural abscess, who had recently completed treatment for disseminated MAI. CASE REPORT The patient was a 65-year-old with AIDS secondary to HIV and a prior history of disseminated MAI, who presented with severe back pain. Upon presentation to the hospital, an MRI was performed, which was suggestive of spondylodiscitis and an epidural abscess. He was taken to surgery for a minimally invasive T12-L1 laminectomy and evacuation of the epidural abscess. Both traditional cultures and acid-fast bacillus (AFB) cultures were negative. Due to worsening pain, he was taken back to surgery for a repeat debridement and biopsy. Repeat cultures were positive for MAI. He was started on rifabutin, ethambutol, azithromycin, and moxifloxacin. Moxifloxacin was subsequently discontinued. He has had problems tolerating the treatment regimen, but is planned to complete an 18-24-month course. CONCLUSIONS For patients with AIDS who have a diagnosis of spondylodiscitis and an epidural abscess, an opportunistic infection such as MAI should be considered. A repeat biopsy should be considered if suspicion is still high, even despite initially negative cultures. Treatment regimens should be prolonged, despite difficulty with medication compliance.

Design of a Fe4 S4 cluster into the core of a de novo four-helix bundle.

We explore the capacity of the de novo protein, S824, to incorporate a multinuclear iron-sulfur cluster within the core of a single-chain four-helix bundle. This topology has a high intrinsic designability because sequences are constrained largely by the pattern of hydrophobic and hydrophilic amino acids, thereby allowing for the extensive substitution of individual side chains. Libraries of novel proteins based on these constraints have surprising functional potential and have been shown to complement the deletion of essential genes in E. coli. Our structure-based design of four first-shell cysteine ligands, one per helix, in S824 resulted in successful incorporation of a cubane Fe4 S4 cluster into the protein core. A number of challenges were encountered during the design and characterization process, including nonspecific metal-induced aggregation and the presence of competing metal-cluster stoichiometries. The introduction of buried iron-sulfur clusters into the helical bundle is an initial step toward converting libraries of designed structures into functional de novo proteins with catalytic or electron-transfer functionalities.

A Completely De Novo ATPase from Combinatorial Protein Design.

Our understanding of biological chemistry is shaped by the observation that all life comes from other life-as Pasteur put it, omne vivum ex vivo. A key step in expanding our biochemical vocabulary is to recapitulate biogenic catalysis using non-natural sequences that did not arise from common ancestry. Here we describe an enzyme designed completely de novo that hydrolyzes ATP. This protein was designed to lack ß-sheet structure and is competitively inhibited by magnesium, two traits that are unlike natural ATPases.

The Face of Clostriodes Difficile Infections in the Outpatient Setting.

BACKGROUND: It has long been well-established that Clostridiodes difficile infections (CDI) can cause severe morbidity and mortality. However, most of the literature to date has focused on hospital-diagnosed infections with less emphasis on clinic-based CDI cases. Guidelines from the 2010 IDSA/SHEA for CDI advocate for metronidazole as first-line therapy for mild to moderate CDI cases. However, the 2017 guidelines recommend oral vancomycin or fidaxomicin as first-line therapy due to their superior efficacy. Objective: The purpose of this study was to compare Clostriodes difficile infections in convenience samples of clinic vs. hospital patients. METHODS: In 2019, a retrospective, case-controlled study was performed by the first six authors between 2015-2017 (i.e., prior to the 2017 IDSA/SHEA CDI guidelines) to compare ambulatory and hospital CDI treatment prescriptions. Analytic data included frequency of White blood cells (WBC) and creatinine collection, frequency of severe CDI cases, compliance with the 2010 guidelines, CDI recurrence, and mortality. RESULTS: An eligible subgroup of N = 92 hospital patients at Spectrum Health Lakeland were more likely to have WBC (98.4% vs 32.6%, p<0.001) and creatinine (97.8 vs. 39.4, P < 0.001) drawn than 184 patients receiving clinic-based care. Hospital sampled patients were more likely to have severe CDI (46.7% vs 6.7%, p < 0.001). Mortality was less common in hospital patients (1.1% vs. 7.6%, p = 0.017) and the recurrence rates were similar. (21.2% inpatient vs. 28.3% outpatient, (p = 0.224). CONCLUSIONS: Based on these results, assessment of CDI severity remains limited in the ambulatory population due to the lack of severity markers. It is unclear if this is due to lack of available laboratory resources or difference in clinical presentation. Of those sample patients who have available markers of severity, patients receiving clinic-based diagnoses were less likely assessed to have severe CDI. Keywords: Cloistriodes difficile infection, ambulatory, severity markers.

A Case of Urinary Sepsis Secondary to Streptococcus sanguinis.

We report a case of a 71-year-old male with a history of BPH who presented with flank pain, fever, chills, abdominal pain, and nausea. He had a dental cleaning 1 month prior to admission and flosses daily. Laboratory data revealed both urine and blood cultures to be positive for streptococcus sanguinis. Computed tomography revealed a 10 mm right ureteral stone, and an ultrasound demonstrated moderate right hydronephrosis. He underwent an ureteroscopy with stent placement. A transesophageal echocardiogram was negative for endocarditis. He completed 2 weeks of IV ceftriaxone and made a complete recovery.

Unevolved De Novo Proteins Have Innate Tendencies to Bind Transition Metals.

Life as we know it would not exist without the ability of protein sequences to bind metal ions. Transition metals, in particular, play essential roles in a wide range of structural and catalytic functions. The ubiquitous occurrence of metalloproteins in all organisms leads one to ask whether metal binding is an evolved trait that occurred only rarely in ancestral sequences, or alternatively, whether it is an innate property of amino acid sequences, occurring frequently in unevolved sequence space. To address this question, we studied 52 proteins from a combinatorial library of novel sequences designed to fold into 4-helix bundles. Although these sequences were neither designed nor evolved to bind metals, the majority of them have innate tendencies to bind the transition metals copper, cobalt, and zinc with high nanomolar to low-micromolar affinity.

Chronic Tenosynovitis due to Mycobacteria kansasii in an Immunocompetent Host.

We report a case of a healthy 56-year-old male who presented with chronic swelling and erythema in his right hand. He had a prior chemical exposure several years ago and subsequent exposure to freshwater, fish tank, and soil. Laboratory data showed a slightly elevated CRP. An MRI was consistent with suggestive of flexor tenosynovitis. He underwent surgical debridement and was diagnosed with Mycobacterium kansasii. He was treated with clarithromycin, rifampin, and isoniazid, but subsequent susceptibility testing revealed resistance to isoniazid. Isoniazid was switched to ethambutol, but further susceptibility testing also suggested resistance to ethambutol. Antimicrobial therapy was stopped at 6 months due to clinical recovery, and the patient is currently doing well as of 6 months postdiscontinuation of therapy.

Metal-binding hydrazone photoswitches for visible light reactivity and variable relaxation kinetics.

The range of applications for photoswitching moieties is diverse, and the ability to design switches with variable photochemical and physical properties is consequently important for realizing their potential. Previously we reported on the photochromism of (E)-N'-(1-(2-hydroxyphenyl)ethylidene)isonicotinohydrazide (HAPI), an aroylhydrazone compound first developed as a transition metal chelator. Herein we report the synthesis of structurally related aroylhydrazone chelators and explore the effect of these modifications on their UVA, UVC and blue light photoreactivity, photostationary state composition, photoisomer thermal stability, and relative iron(iii) binding affinity. These findings will inform the next generation of aroylhydrazone photoswitches for metal-gated photoswitching applications.

Comparison of Acute Kidney Injury During Treatment with Vancomycin and either Piperacillin-Tazobactam or Meropenem.

CONTEXT: Empiric antibiotics are often required in hospitalized patients with serious infections who may be septic and at risk for drug resistant organisms. The purpose of this study was to evaluate the observed incidence of acute kidney injury (AKI) in a sample of adult patients receiving either piperacillin-tazobactam and vancomycin or meropenemvancomycin for at least 72 hours. METHODS: Single-center, retrospective matched cohort at a 200-bed Regional Community Medical Center. Adult patients were included in the sample if they were without preexisting renal dysfunction and admitted over an 18-month time period to receive either the combination of piperacillin-tazobactam and vancomycin or meropenem-vancomycin. Sample patients were evaluated for AKI. This condition was defined by the authors as an increase in serum creatinine of 0.5mg/ml or an increase of 50% above baseline during the duration of antibiotic treatment. RESULTS: A total of 266 patients receiving either combination of antibiotics were evaluated for AKI. The incidence of AKI was significantly higher in the piperacillin-tazobactam and vancomycin group (n = 74/292, 25%) compared with the meropenem-vancomycin group (n=8/74, 9.5%, p=0.008). CONCLUSIONS: The results of this study suggest that the combination of piperacillin-tazobactam and vancomycin is associated with an increased incidence of AKI. Higher vancomycin trough concentrations were associated with increased risk for development of AKI.

Differential Neuroproteomic and Systems Biology Analysis of Spinal Cord Injury.

Acute spinal cord injury (SCI) is a devastating condition with many consequences and no known effective treatment. Although it is quite easy to diagnose traumatic SCI, the assessment of injury severity and projection of disease progression or recovery are often challenging, as no consensus biomarkers have been clearly identified. Here rats were subjected to experimental moderate or severe thoracic SCI. At 24h and 7d postinjury, spinal cord segment caudal to injury center versus sham samples was harvested and subjected to differential proteomic analysis. Cationic/anionic-exchange chromatography, followed by 1D polyacrylamide gel electrophoresis, was used to reduce protein complexity. A reverse phase liquid chromatography-tandem mass spectrometry proteomic platform was then utilized to identify proteome changes associated with SCI. Twenty-two and 22 proteins were up-regulated at 24 h and 7 day after SCI, respectively; whereas 19 and 16 proteins are down-regulated at 24 h and 7 day after SCI, respectively, when compared with sham control. A subset of 12 proteins were identified as candidate SCI biomarkers - TF (Transferrin), FASN (Fatty acid synthase), NME1 (Nucleoside diphosphate kinase 1), STMN1 (Stathmin 1), EEF2 (Eukaryotic translation elongation factor 2), CTSD (Cathepsin D), ANXA1 (Annexin A1), ANXA2 (Annexin A2), PGM1 (Phosphoglucomutase 1), PEA15 (Phosphoprotein enriched in astrocytes 15), GOT2 (Glutamic-oxaloacetic transaminase 2), and TPI-1 (Triosephosphate isomerase 1), data are available via ProteomeXchange with identifier PXD003473. In addition, Transferrin, Cathepsin D, and TPI-1 and PEA15 were further verified in rat spinal cord tissue and/or CSF samples after SCI and in human CSF samples from moderate/severe SCI patients. Lastly, a systems biology approach was utilized to determine the critical biochemical pathways and interactome in the pathogenesis of SCI. Thus, SCI candidate biomarkers identified can be used to correlate with disease progression or to identify potential SCI therapeutic targets.

Clostridium difficile infection and limitations of markers for severity in patients with hematologic malignancy.

OBJECTIVE: To describe characteristics of Clostridium difficile infection (CDI) and markers of severe CDI among patients with hematologic malignancies. DESIGN: Case-control study. SETTING: Tertiary care teaching hospital. PATIENTS AND METHODS: Inpatients with hematologic malignancies and CDI were age and time matched with 2 control inpatients without hematologic malignancies. Chart reviews were performed, and C. difficile isolates were strain typed. RESULTS: Case patients (n = 41) and control patients (n = 82) patients were different in respect to receipt of immunosuppressive agents within 2 months (92.7% vs 25.6%; P < .0001); neutropenia within 2 months (75.6% vs 3.7%; P < .0001) and mean (± standard deviation) white blood cell (WBC) count at diagnosis (vs 4.9 ± 14.1 vs 11.8 ± 6.8 x 10(3) cells/mL; P <.0001); baseline mean creatinine level (0.89 ± 0.1 vs 1.6 ± 2.4 mg/dL; P = .003), mean creatinine level at diagnosis (0.83 ± 0.4 vs 1.85 ± 1.9 mg/dL; P = .004), and creatinine increases of 1.5 times over baseline (2.4% vs 15.1%; P = .02). Immunosuppressive agents and creatinine level remained significant in multivariable analysis (P = .03 for both variables). Severity correlated with mortality when measured by alternate severity criteria but not when measured by the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America criteria, which are based solely on WBC count and creatinine elevation. The prevalence of the epidemic BI/NAP1/027 strain was similar in both groups. CONCLUSIONS: Patients with hematologic malignancies had lower creatinine levels at the time of CDI diagnosis compared with control patients. WBC counts also tended to be lower in case patients. CDI severity criteria based on WBC count and creatinine level may not be applicable to patients with hematologic malignancies.

Experimental demonstration of packet-rate 10-Gb/s OOK OSNR monitoring for QoS-aware cross-layer packet protection.

A cross-layer network platform may enable introspective access to the physical layer, allowing optical performance monitoring measurements to feedback to higher layers for packet rerouting and protection. We experimentally demonstrate quality-of-service-aware packet protection that leverages cross-layer signaling based on the monitoring of packets' optical-signal-to-noise ratio. In order to detect degraded data streams, the monitoring system is based on a delay-line Mach-Zehnder interferometer and a field-programmable gate array. The system is realized in an experimental cross-layer enabled optical packet switched fabric, measuring the optical-signal-to-noise ratio for 10-Gb/s OOK streams. The packet protection scheme uses the dynamic performance measurements to actuate a rerouting of high-quality-of-service packets. 8 × 10-Gb/s wavelength-striped optical messages are rerouted through the fabric error-free (bit-error rates less than 10(-12)).