The Bacillus anthracis genome encodes four superoxide dismutases (SODs), enzymes capable of detoxifying oxygen radicals. That two of these SODs, SOD15 and SODA1, are present in the outermost layers ...of the B. anthracis spore is indicated by previous proteomic analyses of the exosporium. Given the requirement that spores must survive interactions with reactive oxygen species generated by cells such as macrophages during infection, we hypothesized that SOD15 and SODA1 protect the spore from oxidative stress and contribute to the pathogenicity of B. anthracis. To test these theories, we constructed a double-knockout (Δsod15 ΔsodA1) mutant of B. anthracis Sterne strain 34F2 and assessed its lethality in an A/J mouse intranasal infection model. The 50% lethal dose of the Δsod15 ΔsodA1 strain was similar to that of the wild type (34F2), but surprisingly, measurable whole-spore SOD activity was greater than that in 34F2. A quadruple-knockout strain (Δsod15 ΔsodA1 ΔsodC ΔsodA2) was then generated, and as anticipated, spore-associated SOD activity was diminished. Moreover, the quadruple-knockout strain, compared to the wild type, was attenuated more than 40-fold upon intranasal challenge of mice. Spore resistance to exogenously generated oxidative stress and to macrophage-mediated killing correlated with virulence in A/J mice. Allelic exchange that restored sod15 and sodA1 to their wild-type state restored wild-type characteristics. We conclude that SOD molecules within the spore afford B. anthracis protection against oxidative stress and enhance the pathogenicity of B. anthracis in the lung. We also surmise that the presence of four SOD alleles within the genome provides functional redundancy for this key enzyme.
In response to national guidelines, we implemented a two-step testing algorithm for Clostridioides difficile in an effort to improve diagnostic accuracy. Following implementation, we analyzed ...treatment frequency between discordant and concordant patients. We found that the majority of discordant cases were treated with no significant differences in patient characteristics or outcomes between the concordant and discordant groups. Additionally, there were no differences in outcomes when discordant patients were further stratified by treatment status. Given little added diagnostic accuracy with the addition of EIA toxin testing, our facility resumed diagnosis by PCR testing alone. Further studies are needed to investigate alternative processes for improvement in diagnostic accuracy aside from toxin EIA testing including stool submission criteria and educational programs.
ABSTRACT
Deployed clinicians have limited resources at their disposal to augment medical decision-making and management. All deploying personnel undergo predeployment medical assessment to evaluate ...their fitness for deployment. The purpose of predeployment screening is to allow for anticipation of medical needs that may arise which could challenge the available medical resources in an expeditionary environment. Medical standards for deployment are published, identifying disqualifying conditions and medications. A history of latent tuberculosis infection is not disqualifying for deployment. Isoniazid is not specifically mentioned as a disqualifying medication, though it is well known to have the potential of causing drug-induced liver injury. Here, a case of fatal isoniazid-induced drug-induced liver injury in a deployed setting is presented with a review of current latent tuberculosis infection literature. Our goal is for the reader to form their own opinion whether or not isoniazid should be used in the forward environment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Legal wildlife trade creates opportunities for the sale of illegally procured animals and their derivatives, since it is difficult to differentiate legal from laundered items. This problem is common ...across many wildlife trade areas – exotic pets, ornaments, seafood – and involves a variety of taxa. Here, we tested the ability of bulk and compound‐specific stable isotope analysis to help monitor and regulate trade of the yellow‐crested cockatoo Cacatua sulphurea, a critically endangered species threatened by overexploitation for the pet trade. Global trade in wild‐caught yellow‐crested cockatoos was banned in 2002; sale of captive‐bred individuals, however, is still permitted. Our surveys in Hong Kong markets revealed more yellow‐crested cockatoos for sale in 2017–2018 than the total number recorded as legally imported over the previous 13 years, emphasizing the need for a forensic tool to identify the source of the individuals for sale in the markets. Stable isotope analysis was successful at distinguishing between captive and wild cockatoos; we found significant differences between wild and captive cockatoos in both stable carbon (P < 0.001) and stable nitrogen (P < 0.001) isotope values. Linear discriminant analysis allocated samples to the correct group with high reliability (Accuracy = 0.91, Kappa = 0.81), although reliability was lower for some individuals with values on the edge of the distribution. In cases where the bulk isotope analysis was ambiguous, compound‐specific stable isotope analysis, which provides carbon isotope values in specific amino acids, can be applied. We found six amino acids that differed significantly between captive and wild samples, with valine (P = 0.009) being the most informative. Together, stable and compound‐specific isotope analysis represents an important potential forensic tool to help combat illegal trade of cockatoos and could be expanded to other species threatened by wildlife trade.
It is difficult to differentiate legal from laundered items in wildlife trade. Our surveys in Hong Kong markets revealed more yellow‐crested cockatoos Cacatua sulphurea for sale in 2017–2018 than the total number recorded as legally imported over the previous 13 years, emphasizing the need for a forensic tool to identify the source of the individuals for sale in the markets. We found that bulk and compound‐specific stable isotope analyses were successful at distinguishing between captive and wild cockatoos, based on differences in diet. Bulk carbon and nitrogen isotope values differed significantly between wild and captive cockatoos, as did carbon isotopes of six amino acids – with valine being the most informative. Together, stable and compound‐specific isotope analyses were successful at separating captive and wild cockatoos and, upon further validation, could become an important forensic tool to help combat illegal wildlife trade.
A multiplex polymerase chain reaction panel facilitated the more rapid institution of appropriate antimicrobial therapy in patients with acute gastroenteritis compared to traditional diagnostic ...methods.
Abstract
Background
Molecular syndromic diagnostic panels can enhance pathogen identification in the approximately 2-4 billion episodes of acute gastroenteritis that occur annually worldwide. However, the clinical utility of these panels has not been established.
Methods
We conducted a prospective, multi-center study to investigate the impact of the BioFire FilmArray Gastrointestinal polymerase chain reaction panel on clinical diagnosis and decision-making, and compared the clinical acuity of patients with positive results obtained exclusively with the FilmArray with those detected by conventional stool culture. A total of 1887 consecutive fecal specimens were tested in parallel by FilmArray and stool culture. Laboratory and medical records were reviewed to determine rates of detection, turnaround times, clinical features, and the nature and timing of clinical decisions.
Results
FilmArray detected pathogens in 35.3% of specimens, compared to 6.0% for culture. Median time from collection to result was 18 hours for FilmArray and 47 hours for culture. Median time from collection to initiation of antimicrobial therapy was 22 hours for FilmArray and 72 hours for culture. Patients diagnosed by FilmArray were more likely to receive targeted rather than empirical therapy, compared to those diagnosed by culture (P = .0148). Positive Shiga-like toxin-producing E. coli results were reported 47 hours faster with FilmArray and facilitated discontinuation of empirical antimicrobials. Patients diagnosed exclusively by FilmArray had clinical characteristics similar to those identified by culture.
Conclusions
FilmArray markedly improved clinical sensitivity in patients with acute diarrhea, identified cases with clinical acuity comparable to those identified by culture, and enabled clinicians to make more timely and targeted therapeutic decisions.
Anthrax vaccination strategies Cybulski, Robert J.; Sanz, Patrick; O’Brien, Alison D.
Molecular aspects of medicine,
12/2009, Letnik:
30, Številka:
6
Journal Article
Recenzirano
Odprti dostop
The biological attack conducted through the US postal system in 2001 broadened the threat posed by anthrax from one pertinent mainly to soldiers on the battlefield to one understood to exist ...throughout our society. The expansion of the threatened population placed greater emphasis on the reexamination of how we vaccinate against
Bacillus anthracis. The currently-licensed Anthrax Vaccine, Adsorbed (AVA) and Anthrax Vaccine, Precipitated (AVP) are capable of generating a protective immune response but are hampered by shortcomings that make their widespread use undesirable or infeasible. Efforts to gain US Food and Drug Administration (FDA) approval for licensure of a second generation recombinant protective antigen (rPA)-based anthrax vaccine are ongoing. However, this vaccine’s reliance on the generation of a humoral immune response against a single virulence factor has led a number of scientists to conclude that the vaccine is likely not the final solution to optimal anthrax vaccine design. Other vaccine approaches, which seek a more comprehensive immune response targeted at multiple components of the
B.
anthracis organism, are under active investigation. This review seeks to summarize work that has been done to build on the current PA-based vaccine methodology and to evaluate the search for future anthrax prophylaxis strategies.
Owing to concerns of coronavirus disease 2019 (COVID-19) outbreaks, many congregant settings are forced to close when cases are detected because there are few data on the risk of different markers of ...transmission within groups.
To determine whether symptoms and laboratory results on the first day of COVID-19 diagnosis are associated with development of a case cluster in a congregant setting.
This cohort study of trainees with COVID-19 from May 11 through August 24, 2020, was conducted at Joint Base San Antonio-Lackland, the primary site of entry for enlistment in the US Air Force. Symptoms and duration, known contacts, and cycle threshold for trainees diagnosed by reverse transcription-polymerase chain reaction were collected. A cycle threshold value represents the number of nucleic acid amplification cycles that occur before a specimen containing the target material generates a signal greater than the predetermined threshold that defines positivity. Cohorts with 5 or more individuals with COVID-19 infection were defined as clusters. Participants included 10 613 trainees divided into 263 parallel cohorts of 30 to 50 people arriving weekly for 7 weeks of training.
All trainees were quarantined for 14 days on arrival. Testing was performed on arrival, on day 14, and anytime during training when indicated. Protective measures included universal masking, physical distancing, and rapid isolation of trainees with COVID-19.
Association between days of symptoms, specific symptoms, number of symptoms, or cycle threshold values of individuals diagnosed with COVID-19 via reverse transcription-polymerase chain reaction and subsequent transmission within cohorts.
In this cohort study of 10 613 US Air Force basic trainees in 263 cohorts, 403 trainees (3%) received a diagnosis of COVID-19 in 129 cohorts (49%). Among trainees with COVID-19 infection, 318 (79%) were men, and the median (interquartile range IQR) age was 20 (19-23) years; 204 (51%) were symptomatic, and 199 (49%) were asymptomatic. Median (IQR) cycle threshold values were lower in symptomatic trainees compared with asymptomatic trainees (21.2 18.4-27.60 vs 34.8 29.3-37.4; P < .001). Cohorts with clusters of individuals with COVID-19 infection were predominantly men (204 cohorts 89% vs 114 cohorts 64%; P < .001), had more symptomatic trainees (146 cohorts 64% vs 53 cohorts 30%; P < .001), and had more median (IQR) symptoms per patient (3 2-5 vs 1 1-2; P < .001) compared with cohorts without clusters. Within cohorts, subsequent development of clusters of 5 or more individuals with COVID-19 infection compared with those that did not develop clusters was associated with cohorts that had more symptomatic trainees (31 of 58 trainees 53% vs 43 of 151 trainees 28%; P = .001) and lower median (IQR) cycle threshold values (22.3 18.4-27.3 vs 35.3 26.5-37.8; P < .001).
In this cohort study of US Air Force trainees living in a congregant setting during the COVID-19 pandemic, higher numbers of symptoms and lower cycle threshold values were associated with subsequent development of clusters of individuals with COVID-19 infection. These values may be useful if validated in future studies.
Abstract
Background
Men who have sex with men (MSM) are at risk for sexual transmission of enteric pathogens. The microbiology of gastroenteritis in MSM has not been examined since the advent of ...antiretroviral therapy and molecular diagnostics. Our objective was to assess the causes of gastroenteritis among MSM living with and without human immunodeficiency virus (HIV) coinfection in Seattle, Washington.
Methods
We conducted a retrospective cohort study of 235 MSM who underwent multiplex stool polymerase chain reaction (PCR) testing between 1 January 2017 and 1 June 2018. We abstracted clinical and laboratory data from electronic medical records. Parallel or reflexive culture and susceptibility testing were performed when PCR detected cultivable pathogens.
Results
Among 235 MSM tested (268 episodes), 131 had 151 episodes with positive test results. 148 (63.0%) individuals were living with HIV. Among positive tests, 88.7% detected a bacterial pathogen, 26% a virus, and 40% a parasite. Diarrheagenic Escherichia coli (enteroaggretative, enteropathogenic), Shigella, and Campylobacter were the most commonly detected bacteria (33.1%, 30.5%, and 17.2% of positive samples, respectively). Forty-three percent of positive specimens had ≥2 pathogens. Etiologies and clinical presentations were similar between men living with and without HIV. Cultured Shigella and Campylobacter isolates were frequently resistant to multiple antibiotics.
Conclusions
MSM present with gastroenteritis from varied pathogens, including some not detected by conventional stool culture. High levels of antibiotic resistance are consistent with frequent antibiotic exposure in this population and the transmission of multiresistant strains. New approaches are needed to detect, treat, and prevent enteric infections in MSM.
Men who have sex with men have high prevalence of bacterial, parasitic, and viral gastroenteritis, including multidrug-resistant pathogens. Molecular diagnostics can facilitate pathogen detection in this population, but improved surveillance, prevention, and treatment of sexually transmitted enteric infections are needed.
Abstract
Background
Campylobacter species are among the most common causes of enteric bacterial infections worldwide. Men who have sex with men (MSM) are at increased risk for sexually transmitted ...enteric infections, including globally distributed strains of multidrug-resistant Shigella species.
Methods
This was a retrospective study of MSM-associated Campylobacter in Seattle, Washington and Montréal, Québec with phenotypic antimicrobial resistance profiles and whole genome sequencing (WGS).
Results
We report the isolation of 2 clonal lineages of multidrug-resistant Campylobacter coli from MSM in Seattle and Montréal. WGS revealed nearly identical strains obtained from the 2 regions over a 4-year period. Comparison with the National Center for Biotechnology Information’s Pathogen Detection database revealed extensive Campylobacter species clusters carrying multiple drug resistance genes that segregated with these isolates. Examination of the genetic basis of antimicrobial resistance revealed multiple macrolide resistance determinants including a novel ribosomal RNA methyltransferase situated in a CRISPR (clustered regularly interspaced short palindromic repeats) array locus in a C. coli isolate.
Conclusions
As previously reported for Shigella, specific multidrug-resistant strains of Campylobacter are circulating by sexual transmission in MSM populations across diverse geographic locations, suggesting a need to incorporate sexual behavior in the investigation of clusters of foodborne pathogens revealed by WGS data.
We show defined clonal lineages of likely sexually transmitted Campylobacter species associated with spread in men who have sex with men between Seattle and Montréal. We also report the first CRISPR-acquired antibiotic resistance gene in a clinical isolate.
For persons entering congregate settings, optimal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) arrival surveillance screening method, nucleic acid amplification test (NAAT) versus ...rapid antigen detection test (RADT), is debated. To aid this, we sought to determine the risk of secondary symptomatic coronavirus disease 19 (COVID-19) among military trainees with negative arrival NAAT or RADT screening.
Individuals who arrived for US Air Force basic military training from 1 January-31 August 2021 were placed into training groups and screened for SARS-CoV-2 via NAAT or RADT. Secondary symptomatic COVID-19 cases within 2 weeks of training were then measured. A case cluster was defined as ≥5 individual symptomatic COVID-19 cases.
406 (1.6%) of 24 601 trainees screened positive upon arrival. The rate of positive screen was greater for those tested with NAAT versus RADT (2.5% vs 0.4%; RR: 5.4; 95% CI: 4.0-7.3; P < .001). The proportion of training groups with ≥1 positive individual screen was greater in groups screened via NAAT (57.5% vs 10.8%; RR: 5.31; 95% CI: 3.65-7.72; P < .001). However, NAAT versus RADT screening was not associated with a difference in number of training groups to develop a secondary symptomatic case (20.3% vs 22.5%; RR: .9; 95% CI: .66-1.23; P = .53) or case cluster of COVID-19 (4% vs 6.6%; RR: .61; 95% CI: .3-1.22; P = .16).
NAAT versus RADT arrival surveillance screening method impacted individual transmission of COVID-19 but had no effect on number of training groups developing a secondary symptomatic case or case cluster. This study provides consideration for RADT arrival screening in congregate settings.
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