Publications by authors named "Melisa Willby"

Evolving technology and the development of new devices that can aerosolize water present a risk for new sources of Legionella bacteria growth and spread within industrial settings. We investigated a cluster of legionellosis among employees of a manufacturing facility in South Carolina, USA, and found 2 unique equipment sources of Legionella bacteria. The cluster of cases took place during August-November 2022; a total of 34 cases of legionellosis, including 15 hospitalizations and 2 deaths, were reported.

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serogroup 1 sequence types (ST) 213 and 222, a single-locus variant of ST213, were first detected in the early 1990s in the Midwest United States (U.S.) and the late 1990s in the Northeast U.

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Legionnaires disease is a serious pneumonia caused by Legionella bacteria. During November 2022-June 2024, CDC was notified of 12 cases of Legionnaires disease among travelers on two cruise ships; eight on cruise ship A and four on cruise ship B. CDC, in collaboration with the cruise lines, initiated investigations to ascertain the potential sources of on-board exposure after notification of the second potentially associated case for each ship.

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Legionnaires disease is a serious infection acquired by inhalation of water droplets from human-made building water systems that contain Legionella bacteria. On July 11 and 12, 2022, Napa County Public Health (NCPH) in California received reports of three positive urinary antigen tests for Legionella pneumophila serogroup 1 in the town of Napa. By July 21, six Legionnaires disease cases had been confirmed among Napa County residents, compared with a baseline of one or two cases per year.

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A clinically significant mechanism of tuberculosis resistance to the aminoglycoside kanamycin (KAN) is its acetylation catalyzed by upregulated Mycobacterium tuberculosis (Mtb) acetyltransferase Eis. In search for inhibitors of Eis, we discovered an inhibitor with a substituted benzyloxy-benzylamine scaffold. A structure-activity relationship study of 38 compounds in this structural family yielded highly potent (IC ∼ 1 μM) Eis inhibitors, which did not inhibit other acetyltransferases.

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Tuberculosis (TB), caused by (), is a deadly bacterial disease. Drug-resistant strains of make eradication of TB a daunting task. Overexpression of the enhanced intracellular survival (Eis) protein by confers resistance to the second-line antibiotic kanamycin (KAN).

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Fluoroquinolones (FQ) are crucial components of multidrug-resistant tuberculosis (MDR TB) treatment. Differing levels of resistance are associated with specific mutations within the uinolone-esistance-etermining egion (QRDR) of We sequenced the QRDR from serial isolates of MDR TB patients in the Preserving Effective TB Treatment Study (PETTS) with baseline FQ resistance (FQ) or acquired FQ resistance (FQ) using an Ion Torrent Personal Genome Machine (PGM) to a depth of 10,000× and reported single nucleotide polymorphisms in ≥1% of reads. FQ isolates harbored 15 distinct alleles with 1.

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The enhanced intracellular survival (Eis) protein of () is a versatile acetyltransferase that multiacetylates aminoglycoside antibiotics abolishing their binding to the bacterial ribosome. When overexpressed as a result of promoter mutations, Eis causes drug resistance. In an attempt to overcome the Eis-mediated kanamycin resistance of , we designed and optimized structurally unique thieno[2,3-]pyrimidine Eis inhibitors toward effective kanamycin adjuvant combination therapy.

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A common cause of resistance to kanamycin (KAN) in tuberculosis is overexpression of the enhanced intracellular survival (Eis) protein. Eis is an acetyltransferase that multiacetylates KAN and other aminoglycosides, rendering them unable to bind the bacterial ribosome. By high-throughput screening, a series of substituted 1,2,4-triazino[5,6 b]indole-3-thioether molecules were identified as effective Eis inhibitors.

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Bacterial nucleoid-associated proteins (NAPs) are critical to genome integrity and chromosome maintenance. Post-translational modifications of bacterial NAPs appear to function similarly to their better studied mammalian counterparts. The histone-like NAP HupB from Mycobacterium tuberculosis (Mtb) was previously observed to be acetylated by the acetyltransferase Eis, leading to genome reorganization.

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Pyrazinamide (PZA) is a standard component of first-line treatment regimens for and is included in treatment regimens for drug-resistant whenever possible. Therefore, it is imperative that susceptibility to PZA be assessed reliably prior to the initiation of therapy. Currently available growth-based PZA susceptibility tests are time-consuming, and results can be inconsistent.

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Tuberculosis (TB) remains one of the leading causes of mortality worldwide. Hence, the identification of highly effective antitubercular drugs with novel modes of action is crucial. In this paper, we report the discovery and development of pyrrolo[1,5-a]pyrazine-based analogues as highly potent inhibitors of the Mycobacterium tuberculosis (Mtb) acetyltransferase enhanced intracellular survival (Eis), whose up-regulation causes clinically observed resistance to the aminoglycoside (AG) antibiotic kanamycin A (KAN).

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Drug-resistant tuberculosis (TB) is a global threat and innovative approaches such as using adjuvants of anti-TB therapeutics are required to combat it. High-throughput screening yielded two lead scaffolds of inhibitors of () acetyltransferase Eis, whose upregulation causes resistance to the anti-TB drug kanamycin (KAN). Chemical optimization on these scaffolds resulted in potent Eis inhibitors.

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Article Synopsis
  • * Researchers used high-throughput screening to identify a sulfonamide scaffold, which they modified to enhance its ability to inhibit Eis and counteract KAN resistance, resulting in several potent inhibitors.
  • * A crystal structure analysis confirmed how one of the most effective inhibitors interacts with Eis, providing insights for the development of new aminoglycoside combinations to treat resistant tuberculosis in preclinical stages.
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A major cause of tuberculosis (TB) resistance to the aminoglycoside kanamycin (KAN) is the Mycobacterium tuberculosis (Mtb) acetyltransferase Eis. Upregulation of this enzyme is responsible for inactivation of KAN through acetylation of its amino groups. A 123 000-compound high-throughput screen (HTS) yielded several small-molecule Eis inhibitors that share an isothiazole S,S-dioxide heterocyclic core.

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Background: We combined hospital-based surveillance and health utilization survey data to estimate the incidence of respiratory viral infections associated hospitalization among children aged < 5 years in Bangladesh.

Methods: Surveillance physicians collected respiratory specimens from children aged <5 years hospitalized with respiratory illness and residing in the primary hospital catchment areas. We tested respiratory specimens for respiratory syncytial virus, parainfluenza viruses, human metapneumovirus, influenza, adenovirus and rhinoviruses using rRT-PCR.

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WU polyomavirus (WUPyV) was detected in a bone marrow transplant recipient with severe acute respiratory distress syndrome who died in 2001. Crystalline lattices of polyomavirus-like particles were observed in the patient's lung by electron microscopy. WUPyV was detected in the lung and other tissues by real-time quantitative PCR and identified in the lung and trachea by immunohistochemistry.

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Despite the interactions known to occur between various lower respiratory tract pathogens and alveolar epithelial cells (AECs), few reports examine factors influencing the interplay between Mycobacterium tuberculosis bacilli and AECs during infection. Importantly, in vitro studies have demonstrated that the M. tuberculosis hbha and esxA gene products HBHA and ESAT6 directly or indirectly influence AEC survival.

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Sequencing of the Mycobacterium tuberculosis pncA gene allows for pyrazinamide susceptibility testing. We summarize data on pncA polymorphisms that do not confer resistance at a susceptibility breakpoint of 100 μg/ml pyrazinamide in MGIT within a cohort of isolates from South Africa and the U.S.

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The newer fluoroquinolones moxifloxacin (MXF) and levofloxacin (LVX) are becoming more common components of tuberculosis (TB) treatment regimens. However, the critical concentrations for testing susceptibility of Mycobacterium tuberculosis to MXF and LVX are not yet well established. Additionally, the degree of cross-resistance between ofloxacin (OFX) and these newer fluoroquinolones has not been thoroughly investigated.

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As the prevalence of multidrug-resistant and extensively drug-resistant tuberculosis strains continues to rise, so does the need to develop accurate and rapid molecular tests to complement time-consuming growth-based drug susceptibility testing. Performance of molecular methods relies on the association of specific mutations with phenotypic drug resistance and while considerable progress has been made for resistance detection of first-line antituberculosis drugs, rapid detection of resistance for second-line drugs lags behind. The rrs A1401G allele is considered a strong predictor of cross-resistance between the three second-line injectable drugs, capreomycin (CAP), kanamycin, and amikacin.

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Owing to the rise in drug resistance in tuberculosis combined with the global spread of its causative pathogen, Mycobacterium tuberculosis (Mtb), innovative anti mycobacterial agents are urgently needed. Recently, we developed a novel primase-pyrophosphatase assay and used it to discover inhibitors of an essential Mtb enzyme, primase DnaG (Mtb DnaG), a promising and unexplored potential target for novel antituberculosis chemotherapeutics. Doxorubicin, an anthracycline antibiotic used as an anticancer drug, was found to be a potent inhibitor of Mtb DnaG.

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Fluoroquinolone antibiotics are among the most potent second-line drugs used for treatment of multidrug-resistant tuberculosis (MDR TB), and resistance to this class of antibiotics is one criterion for defining extensively drug resistant tuberculosis (XDR TB). Fluoroquinolone resistance in Mycobacterium tuberculosis has been associated with modification of the quinolone resistance determining region (QRDR) of gyrA. Recent studies suggest that amino acid substitutions in gyrB may also play a crucial role in resistance, but functional genetic studies of these mutations in M.

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Background: Human coronaviruses (HCoVs) have been detected in children with upper and lower respiratory symptoms, but little is known about their relationship with severe respiratory illness.

Objective: To compare the prevalence of HCoV species among children hospitalized for acute respiratory illness and/or fever (ARI/fever) with that among asymptomatic controls and to assess the severity of outcomes among hospitalized children with HCoV infection compared with other respiratory viruses.

Methods: From December 2003 to April 2004 and October 2004 to April 2005, we conducted prospective, population-based surveillance of children <5 years of age hospitalized for ARI/fever in 3 US counties.

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