Publications by authors named "Juan C Salazar"

Pyoverdines are high affinity siderophores produced by most with a wide role in microbial interspecies interactions. They are primarily composed of a conserved chromophore moiety, an acyl side chain and a peptide backbone which may be highly variable among strains. Upon ferric iron sequestration, pyoverdines are internalized through specialized receptors.

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  • Research highlights a critical gap in understanding long COVID (PASC) in children and emphasizes the need for studies that define its characteristics in this age group.
  • The objective is to identify common prolonged symptoms in children aged 6 to 17 post-SARS-CoV-2 infection, examining differences between school-age kids and adolescents, as well as potential symptom clusters for future research.
  • A multicenter study involved nearly 5,000 participants, revealing that certain symptoms were significantly more prevalent in those with a history of COVID-19 compared to those without.
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  • The study focuses on understanding the molecular epidemiology of Treponema pallidum subspecies pallidum (TPA) to aid in the development of a global syphilis vaccine by analyzing clinical data and specimens from early syphilis patients across multiple countries.* -
  • Enrolling 233 patients with primary and secondary syphilis from China, Colombia, Malawi, and the USA, researchers utilized whole-genome sequencing (WGS) to study TPA strains, revealing important demographic information and a significant presence of HIV co-infections among participants.* -
  • The findings highlighted a dominance of SS14-lineage strains with geographical distribution patterns, confirming genetic differences in the Nichols-lineage strains, which could inform future vaccine strategies and
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  • Despite the genetic code's conservation, codon usage varies due to mutational bias and selection pressures, influenced by environmental factors and tRNA concentration.
  • tRNA modifications are crucial in determining codon preference in proteobacteria.
  • Certain codons, like CGA and AGG, show low variability in usage across different genomes, indicating that codon evolution in proteobacteria may be tied to specific codons affected by tRNA modifications.
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Shiga toxin-producing (STEC) poses a significant public health risk due to its zoonotic potential and association with severe human diseases, such as hemorrhagic colitis and hemolytic uremic syndrome. Ruminants are recognized as primary reservoirs for STEC, but swine also contribute to the epidemiology of this pathogen, highlighting the need for effective prevention strategies across species. Notably, a subgroup of STEC that produces Shiga toxin type 2e (Stx2e) causes edema disease (ED) in newborn piglets, economically affecting pig production.

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Background: Venereal syphilis, caused by the spirochete Treponema pallidum subsp. pallidum (TPA), is surging worldwide, underscoring the need for a vaccine with global efficacy. Vaccine development requires an understanding of syphilis epidemiology and clinical presentation as well as genomic characterization of TPA strains circulating within at-risk populations.

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There is minimal knowledge regarding the durability of neutralization capacity and level of binding antibody generated against the highly transmissible circulating Omicron subvariants following SARS-CoV-2 infection in children with acute COVID-19 and those diagnosed with multisystem inflammatory syndrome in children (MIS-C) in the absence of vaccination. In this study, SARS-CoV-2 neutralization titers against the ancestral strain (WA1) and Omicron sublineages were evaluated in unvaccinated children admitted for COVID-19 ( = 32) and MIS-C ( = 32) at the time of hospitalization (baseline) and at six to eight weeks post-discharge (follow-up) between 1 April 2020, and 1 September 2022. In addition, antibody binding to the spike receptor binding domain (RBD) from WA1, BA.

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Multisystem Inflammatory Syndrome in Children (MIS-C) is a potentially life-threatening complication of COVID-19. The pathophysiological mechanisms leading to severe disease are poorly understood. This study leveraged clinical samples from a well-characterized cohort of children hospitalized with COVID-19 or MIS-C to compare immune-mediated biomarkers.

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Background: The global resurgence of syphilis necessitates vaccine development.

Methods: We collected ulcer exudates and blood from 17 participants with primary syphilis (PS) and skin biopsies and blood from 51 patients with secondary syphilis (SS) in Guangzhou, China, for Treponema pallidum subsp pallidum (TPA) quantitative polymerase chain reaction, whole genome sequencing (WGS), and isolation of TPA in rabbits.

Results: TPA DNA was detected in 15 of 17 ulcer exudates and 3 of 17 blood PS specimens.

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Objective This study aimed to quantify the effect of social media posts on study enrollment among children with mild coronavirus disease 2019 (COVID-19). Methods The primary outcome was weekly study enrollments analyzed using a run chart. A secondary analysis used linear regression to assess study enrollments two days before and after a social media post, adjusted for the statewide pediatric seven-day-average severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) case rate, social media posting day, and the interaction of these two variables.

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Infection by the enteric pathogen requires transit through the gastrointestinal tract and invasion of and replication within the cells of the host colonic epithelium. This process exposes the pathogen to a range of diverse microenvironments. Furthermore, the unique composition and physical environment of the eukaryotic cell cytosol represents a stressful environment for , and extensive physiological adaptations are needed for the bacterium to thrive.

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Background: The global resurgence of syphilis requires novel prevention strategies. Whole genome sequencing (WGS) of ( ) using different specimen types is essential for vaccine development.

Methods: Patients with primary (PS) and secondary (SS) syphilis were recruited in Guangzhou, China.

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Background: The continuing increase in syphilis rates worldwide necessitates development of a vaccine with global efficacy. We conducted a multi-center, observational study to explore subsp. ( ) molecular epidemiology essential for vaccine research by analyzing clinical data and specimens from early syphilis patients using whole-genome sequencing (WGS) and publicly available WGS data.

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Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious condition that can develop 4-6 weeks after a school age child becomes infected by SARS-CoV-2. To date, in the United States more than 8,862 cases of MIS-C have been identified and 72 deaths have occurred. This syndrome typically affects children between the ages of 5-13; 57% are Hispanic/Latino/Black/non-Hispanic, 61% of patients are males and 100% have either tested positive for SARS-CoV-2 or had direct contact with someone with COVID-19.

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  • The study evaluated the effectiveness of two rapid diagnostic tests (RDTs) for syphilis (Bioline and Determine) specifically in people living with HIV (PLWH) in Cali, Colombia.
  • A total of 244 participants were studied, revealing high sensitivity for Bioline and variability in Determine's performance based on sample type and ART status.
  • Despite the overall excellent performance of the RDTs for screening syphilis in PLWH, concerns were noted regarding the lower sensitivity of Determine on capillary blood compared to serum samples.
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Shiga toxin-producing (STEC) is a zoonotic pathogen that causes gastroenteritis and Hemolytic Uremic Syndrome. Cattle are the main animal reservoir, excreting the bacteria in their feces and contaminating the environment. In addition, meat can be contaminated by releasing the intestinal content during slaughtering.

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Sequencing of most genomes excludes repeat regions in and the gene, encoding the acidic repeat protein (). As a first step to understanding the evolution and function of these genes and the proteins they encode, we developed a protocol to nanopore sequence and genes from 212 clinical samples collected from ten countries on six continents. Both and repeat structures recapitulate the whole genome phylogeny, with subclade-specific patterns emerging.

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Background: Multisystem inflammatory syndrome in children (MIS-C) is a novel disease that was identified during the COVID-19 pandemic and is characterised by systemic inflammation following SARS-CoV-2 infection. Early detection of MIS-C is a challenge given its clinical similarities to Kawasaki disease and other acute febrile childhood illnesses. We aimed to develop and validate an artificial intelligence algorithm that can distinguish among MIS-C, Kawasaki disease, and other similar febrile illnesses and aid in the diagnosis of patients in the emergency department and acute care setting.

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The resurgence of syphilis in the new millennium has called attention to the importance of a vaccine for global containment strategies. Studies with immune rabbit serum (IRS) indicate that a syphilis vaccine should elicit antibodies (Abs) that promote opsonophagocytosis of treponemes by activated macrophages. The availability of three-dimensional models for Treponema pallidum's () repertoire of outer membrane proteins (OMPs) provides an architectural framework for identification of candidate vaccinogens with extracellular loops (ECLs) as the targets for protective Abs.

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Shigellosis is an enteric infectious disease in which antibiotic treatment is effective, shortening the duration of symptoms and reducing the excretion of the pathogen into the environment. spp., the etiologic agent, are considered emerging pathogens with a high public health impact due to the increase and global spread of multidrug-resistant (MDR) strains.

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