Active Tuberculosis After Solid Organ Transplantation in Individuals With Negative Pretransplant QuantiFERON-TB Gold Testing: A Case Series.

Active tuberculosis (TB) in solid organ transplant (SOT) recipients most commonly occurs due to reactivation of latent infection and is associated with poor clinical outcomes, including allograft loss and death. National transplant societies, including the American Society of Transplantation, recommend screening for latent TB prior to transplant, with treatment in the peritransplant setting to reduce the subsequent risk of TB reactivation. Though screening is traditionally conducted using laboratory-based assays, such as the QuantiFERON-TB Gold, false negatives may occur in SOT candidates due to anergy from end-stage organ dysfunction, highlighting the need for a multimodal diagnostic approach.

Mitigation of a Coronavirus Disease 2019 Outbreak in a Nursing Home Through Serial Testing of Residents and Staff.

Nursing homes and long-term care facilities represent highly vulnerable environments for respiratory disease outbreaks, such as coronavirus disease 2019 (COVID-19). We describe a COVID-19 outbreak in a nursing home that was rapidly contained by using a universal testing strategy of all residents and nursing home staff.

A Case of Disseminated Histoplasmosis in a Patient with Rheumatoid Arthritis on Abatacept.

Biologic agents are effective treatments for rheumatoid arthritis but are associated with important risks, including severe infections. Tumor Necrosis Factor (TNF) α inhibitors are known to increase the risk of systemic fungal infections such as disseminated histoplasmosis. Abatacept is a biologic agent with a mechanism different from that of TNFα inhibitors: It suppresses cellular immunity by competing for the costimulatory signal on antigen-presenting cells.

Rasamsonia argillacea pulmonary and aortic graft infection in an immune-competent patient.

Rasamsonia argillacea (formerly known as Geosmithia argillacea) is a fungus recently recognized as a pathogen of immunocompromised patients. Here we report the first case of Rasamsonia infection in an immunocompetent host, presenting as a pulmonary and aortic graft infection. Its morphological similarity to nonpathogenic Penicillium species delayed the diagnosis and initiation of appropriate treatment.

Identification of eukaryotic promoter regulatory elements using nonhomologous random recombination.

Understanding the regulatory logic of a eukaryotic promoter requires the elucidation of the regulatory elements within that promoter. Current experimental or computational methods to discover regulatory motifs within a promoter can be labor intensive and may miss redundant, unprecedented or weakly activating elements. We have developed an unbiased combinatorial approach to rapidly identify new upstream activating sequences (UASs) in a promoter.

Directed evolution and substrate specificity profile of homing endonuclease I-SceI.

The laboratory evolution of enzymes with tailor-made DNA cleavage specificities would represent new tools for manipulating genomes and may enhance our understanding of sequence-specific DNA recognition by nucleases. Below we describe the development and successful application of an efficient in vivo positive and negative selection system that applies evolutionary pressure either to favor the cleavage of a desired target sequence or to disfavor the cleavage of nontarget sequences. We also applied a previously described in vitro selection method to reveal the comprehensive substrate specificity profile of the wild-type I-SceI homing endonuclease.

DNA-templated organic synthesis and selection of a library of macrocycles.

The translation of nucleic acid libraries into corresponding synthetic compounds would enable selection and amplification principles to be applied to man-made molecules. We used multistep DNA-templated organic synthesis to translate libraries of DNA sequences, each containing three "codons," into libraries of sequence-programmed synthetic small-molecule macrocycles. The resulting DNA-macrocycle conjugates were subjected to in vitro selections for protein affinity.

Highly sensitive in vitro selections for DNA-linked synthetic small molecules with protein binding affinity and specificity.

We have developed in vitro selections for DNA-linked synthetic small molecules with protein binding affinity and specificity. These selections require only generally accessible equipment, offer high degrees of enrichment of active molecules from mixtures of predominantly inactive species, can be applied to a variety of unrelated proteins, and require approximately 108-fold less material than existing synthetic molecule screening methods. Iterating these selections multiplies the net enrichment of active molecules, enabling enormous overall enrichment factors exceeding 106 to be achieved.

Twisted amides inferred from QSAR analysis of hydrophobicity and electronic effects on the affinity of fluoroaromatic inhibitors of carbonic anhydrase.

QSAR has been used to elucidate the origin of the hydrophobicity and binding affinity of a small library of fluoroaromatic inhibitors of F131V carbonic anhydrase II. Our analysis predicted the presence of a twisted amide conformation for several bound inhibitors, which we confirmed crystallographically. We also determined that the hydrophobicity of the inhibitors as a whole results from the fragment hydrophobicities of their fluorobenzyl rings, corrected for field effects and the presence of an intramolecular F.