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The emergence of SARS-CoV-2 and the subsequent pandemic has highlighted the need for animal models that faithfully replicate the salient features of COVID-19 disease in humans. These models are necessary for the rapid selection, testing, and evaluation of potential medical countermeasures. Here, we performed a direct comparison of two distinct routes of SARS-CoV-2 exposure-combined intratracheal/intranasal and small particle aerosol-in two nonhuman primate species, rhesus and cynomolgus macaques. While all four experimental groups displayed very few outward clinical signs, evidence of mild to moderate respiratory disease was present on radiographs and at necropsy. Cynomolgus macaques exposed via the aerosol route also developed the most consistent fever responses and had the most severe respiratory disease and pathology. This study demonstrates that while all four models produced suitable representations of mild COVID-like illness, aerosol exposure of cynomolgus macaques to SARS-CoV-2 produced the most severe disease, which may provide additional clinical endpoints for evaluating therapeutics and vaccines.
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COVID-19 , Aerosoles , Animales , Modelos Animales de Enfermedad , Macaca fascicularis , SARS-CoV-2 , Índice de Severidad de la EnfermedadRESUMEN
Airborne transmission is predicted to be a prevalent route of human exposure with SARS-CoV-2. Aside from African green monkeys, nonhuman primate models that replicate airborne transmission of SARS-CoV-2 have not been investigated. A comparative evaluation of COVID-19 in African green monkeys, rhesus macaques, and cynomolgus macaques following airborne exposure to SARS-CoV-2 was performed to determine critical disease parameters associated with disease progression, and establish correlations between primate and human COVID-19. Respiratory abnormalities and viral shedding were noted for all animals, indicating successful infection. Cynomolgus macaques developed fever, and thrombocytopenia was measured for African green monkeys and rhesus macaques. Type II pneumocyte hyperplasia and alveolar fibrosis were more frequently observed in lung tissue from cynomolgus macaques and African green monkeys. The data indicate that, in addition to African green monkeys, macaques can be successfully infected by airborne SARS-CoV-2, providing viable macaque natural transmission models for medical countermeasure evaluation.
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COVID-19/fisiopatología , Modelos Animales de Enfermedad , Macaca mulatta , SARS-CoV-2/fisiología , Animales , COVID-19/patología , COVID-19/transmisión , Chlorocebus aethiops , Transmisión de Enfermedad Infecciosa , Femenino , Pulmón/patología , Macaca fascicularis , Masculino , Esparcimiento de VirusRESUMEN
Zika virus (ZIKV) is a mosquito-borne member of the genus Flavivirus that has emerged since 2007 to cause outbreaks in Africa, Asia, Oceania, and most recently, in the Americas. Here, we used an isolate history as well as genetic and phylogenetic analyses to characterize three low-passage isolates representing African (ArD 41525) and Asian (CPC-0740, SV0127-14) lineages to investigate the potential phenotypic differences in vitro and in vivo. The African isolate displayed a large plaque phenotype (â¼3-4 mm) on Vero and HEK-293 cells, whereas the Asian isolates either exhibited a small plaque phenotype (â¼1-2 mm) or did not produce any plaques. In multistep replication kinetics in nine different vertebrate and insect cell lines, the African isolate consistently displayed faster replication kinetics and yielded â¼10- to 10,000-fold higher peak virus titers (infectious or RNA copies) compared with the Asian isolates. Oral exposure of Aedes aegypti mosquitoes with the African isolate yielded higher infection and dissemination rates compared with the Asian isolates. Infection of Ifnar1-/- mice with the African isolate produced a uniformly fatal disease, whereas infection with the Asian isolates produced either a delay in time-to-death or a significantly lower mortality rate. Last, the African isolate was > 10,000-fold more virulent than the Asian isolates in an interferon type I antibody blockade mouse model. These data demonstrate substantial phenotypic differences between low-passage African and Asian isolates both in vitro and in vivo and warrant further investigation. They also highlight the need for basic characterization of ZIKV isolates, as the utilization of the uncharacterized isolates could have consequences for animal model and therapeutic/vaccine development.
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Variación Biológica Poblacional/genética , Virus Zika/aislamiento & purificación , Aedes/virología , África , Américas , Animales , Asia , Modelos Animales de Enfermedad , Femenino , Humanos , Ratones/virología , Ratones Endogámicos C57BL/virología , Mosquitos Vectores/virología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Virus Zika/genética , Infección por el Virus Zika/epidemiología , Infección por el Virus Zika/genéticaRESUMEN
Research involving biosafety level 3 pathogens such as West Nile virus (WNV) is often limited by the limited space and technical constraints of these environments. To conduct complex analytical studies outside of high containment, robust and reliable inactivation methods are needed that maintain compatibility with downstream assays. Here we report the inactivation of WNV in spiked serum samples using a commercially available SDS-PAGE sample buffer for proteomic studies. Using this method, we demonstrate its utility by identification proteins differentially expressed in the serum of mice experimentally infected with WNV.
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Proteínas Sanguíneas/metabolismo , Detergentes/farmacología , Calor , Proteómica/métodos , Sustancias Reductoras/farmacología , Suero/virología , Inactivación de Virus , Virus del Nilo Occidental/fisiología , Animales , Tampones (Química) , Ditiotreitol/farmacología , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Ratones , Dodecil Sulfato de Sodio/farmacología , Tensoactivos/farmacología , Ensayo de Placa Viral , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/efectos de los fármacosRESUMEN
INTRODUCTION: Live vaccine strain (LVS) Francisella tularensis is a live, attenuated investigational tularemia vaccine that has been used by the US Army for decades to protect laboratory workers. Postvaccination bacterial kinetic characteristics of LVS at the inoculation site and in the blood are unknown and, therefore, were assessed in a prospective study. LVS vaccination of laboratory workers provided the opportunity to compare culture with polymerase chain reaction (PCR) for the detection of F. tularensis in human clinical samples. METHODS: Blood and skin swab samples were prospectively collected from volunteers who received the LVS tularemia vaccine at baseline (negative controls) and at 5 specified time points (days 1, 2, 7 or 8, 14 or 15, and 35 after vaccination). Bacterial culture and PCR of whole blood samples (17 volunteers) and inoculation site swabs (41 volunteers) were performed. RESULTS: The culture and PCR results of all blood samples were negative. Results of real-time PCR from the inoculation site samples were positive for 41 (100%) of 41 volunteers on day 1, for 40 (97.6%) of 41 volunteers on day 2, for 24 (58.5%) of 41 on day 7 or 8, for 6 (16.7%) of 36 on day 14 or 15, and for 0 (0%) of 9 on day 35. Positive results of bacterial cultures of the inoculation site samples occurred significantly less frequently, compared with PCR testing, with 4 (9.8%) of 41 volunteers having positive results on day 1 (P<.001) and 4 (9.8%) of 41 on day 2 (P<.001); all results from subsequent days were negative. CONCLUSIONS: F. tularensis LVS genomic DNA was detected in the majority of samples from the inoculation site up to 1 week after LVS vaccination, with real-time PCR being more sensitive than culture. Our data suggest that bacteremia does not occur after LVS vaccination in normal, healthy human volunteers.
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Vacunas Bacterianas , Francisella tularensis/inmunología , Francisella tularensis/aislamiento & purificación , Tularemia/prevención & control , Adulto , Vacunas Bacterianas/administración & dosificación , Vacunas Bacterianas/sangre , Vacunas Bacterianas/inmunología , Técnicas de Cultivo de Célula/métodos , ADN Bacteriano/sangre , Femenino , Francisella tularensis/genética , Pruebas Hematológicas/métodos , Humanos , Masculino , Persona de Mediana Edad , Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena de la Polimerasa/métodos , Pruebas Serológicas , Tularemia/microbiologíaRESUMEN
Here, we sequenced the completed genome of Yersinia pestis EV76D and KIM 10v, two genomes used as references in assay development, to improved high-quality draft status.
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We sequenced the complete genome of Francisella novicida DPG 3A-IS to closed and finished status. This is a warm spring isolate recovered from Hobo Warm Spring (Utah, USA). The final assembly is available in NCBI under accession number CP012037.
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Francisella tularensis is a highly infectious bacterium with the potential to cause high fatality rates if infections are untreated. To aid in the development of rapid and accurate detection assays, we have sequenced and annotated the genomes of 18 F. tularensis and Francisella philomiragia strains.
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The genus Yersinia includes three human pathogens, of which Yersinia pestis is responsible for >2,000 illnesses each year. To aid in the development of detection assays and aid further phylogenetic elucidation, we sequenced and assembled the complete genomes of 32 strains (across 9 Yersinia species).
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In 2011, the Association of Analytical Communities (AOAC) International released a list of Bacillus strains relevant to biothreat molecular detection assays. We present the complete and annotated genome assemblies for the 15 strains listed on the inclusivity panel, as well as the 20 strains listed on the exclusivity panel.
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The genus Burkholderia encompasses both pathogenic (including Burkholderia mallei and Burkholderia pseudomallei, U.S. Centers for Disease Control and Prevention Category B listed), and nonpathogenic Gram-negative bacilli. Here we present full genome sequences for a panel of 59 Burkholderia strains, selected to aid in detection assay development.
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Acinetobacter baumannii is an emerging nosocomial pathogen, and therefore high-quality genome assemblies for this organism are needed to aid in detection, diagnostic, and treatment technologies. Here we present the improved draft assembly of A. baumannii ATCC 19606 in two scaffolds. This 3,953,621-bp genome contains 3,750 coding regions and has a 39.1% G+C content.
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The relationship of mucoviscosity-associated (magA) and/or regulator of mucoid phenotype (rmpA) genes to the Klebsiella pneumoniae hypermucoviscosity (HMV) phenotype has been reported. We previously demonstrated that rmpA+ K. pneumoniae can cause serious disease in African green monkeys and isolated rmpA+ and magA+ HMV K. pneumoniae from other species of non-human primates. To rapidly screen African green monkeys/non-human primates for these infections, we developed three real-time PCR assays. The first was K. pneumoniae-specific, targeting the khe gene, while the others targeted rmpA and magA. Primer Express 2 was used with the three K. pneumoniae genes to generate sequence-specific TaqMan/TaqMan-Minor Groove Binder assays. Oral/rectal swabs and necropsy samples were collected; swabs were used for routine culture and DNA extraction. K. pneumoniae colonies were identified on the Vitek 2 with DNA tested using the K. pneumoniae-specific assays. Testing of 45 African green monkeys resulted in 19 khe+ samples from 14 animals with none positive for either rmpA or magA. Of these 19 khe+ samples, five were culture-positive, but none were HMV "string test"-positive. Subsequent testing of 307 non-human primates resulted in 64 HMV K. pneumoniae isolates of which 42 were rmpA+ and 15 were magA+. Non-human primate testing at the U.S. Army Medical Research Institute of Infectious Diseases demonstrated the ability to screen both live and necropsied animals for K. pneumoniae by culture and real-time PCR to determine HMV genotype.
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Proteínas Bacterianas/genética , Infecciones por Klebsiella/diagnóstico , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/genética , Reacción en Cadena de la Polimerasa/métodos , Animales , Chlorocebus aethiops , Klebsiella pneumoniae/aislamiento & purificación , Fenotipo , Primates , ViscosidadRESUMEN
Development of rapid amplification assays for the detection and identification of biological threat agents has become a focus of diagnostic efforts in recent years. The use of real-time PCR assays as diagnostic tools depends upon two critical processes. First, nucleic acid purification must provide template that is both amplifiable and free of PCR inhibitors. Second, the assays themselves must be sensitive and specific for their nucleic acid targets. A differentiation must be made between results achieved due to the lack of target nucleic acid (true negatives) and those produced due to the inability to amplify target DNA (false negatives) so confidence in negative reactions is possible. False negatives can occur when inhibitors are present in the sample being tested, especially if clinical samples such as blood are analyzed. To address the problem of detecting inhibition in purified nucleic acids, an exogenous internal positive control (IPC) based on Taqman chemistry was developed. A previously optimized assay was cloned and the primer and probe sites were mutated to produce novel sequences with no known homology to published sequence data. The IPC was sensitive to a variety of inhibitors, including hemoglobin, heparin, EDTA, humic acids, and fulvic acid. It was also equally sensitive to inhibition when labeled with either 6FAM or ROX dyes. In addition, the IPC was successfully multiplexed with agent specific assays without any loss in their sensitivity. The designed IPC assay has proven to be an effective tool for monitoring inhibitors of PCR and builds confidence in negative results obtained with agent specific assays.
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Reacción en Cadena de la Polimerasa/normas , Juego de Reactivos para Diagnóstico/normas , Reacciones Falso Negativas , Métodos , Mutagénesis Sitio-Dirigida , Estándares de Referencia , Sensibilidad y Especificidad , Manejo de EspecímenesRESUMEN
Efficient, rapid, and reproducible procedures for isolating high-quality DNA before PCR gene amplification are essential for the diagnostic and molecular identification of pathogenic bacteria. This study evaluated the Qiagen QIAamp DNA Mini Kit and the Schleicher and Schuell IsoCode Stix DNA isolation device for isolating nucleic acid. Buffer, serum, and whole-blood samples were spiked with Bacillus anthracis Sterne vegetative cells and Yersinia pestis, while water was spiked with B. anthracis Sterne spores. Although minimal variations in limit of detection occurred among matrices, both the IsoCode Stix extraction method and the Qiagen procedure have comparable detection limits.