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miércoles, 28 de febrero de 2018

Botulinum neurotoxin–encoding plasmids can be conjugatively transferred to diverse clostridial strains #Clostridium

Most Group I Clostridium botulinum strains harbor botulinum neurotoxin (bont) genes on their chromosome, while some carry these genes (including bont/a, bont/b, and bont/f) on large plasmids. Prior work in our laboratory demonstrated that Group I BoNT plasmids were mobilized to C. botulinum recipient strains containing the Tn916 transposon. Here, we show that Tn916 is nonessential for plasmid transfer. Relying on an auxotrophic donor phenotype and a plasmid-borne selectable marker, we observed the transfer of pCLJ, a 270 kb plasmid harboring two bont genes, from its host strain to various clostridia. Transfer frequency was greatest to other Group I C. botulinum strains, but the plasmid was also transferred into traditionally nontoxigenic species, namely C. sporogenes and C. butyricum. Expression and toxicity of BoNT/A4 was confirmed in transconjugants by immunoblot and mouse bioassay. These data indicate that conjugation within the genus Clostridium can occur across physiological Groups of C. botulinum, supporting horizontal gene transfer via bont-bearing plasmids. The transfer of plasmids possessing bont genes to resistant Clostridium spp. such as C. sporogenes could impact biological safety for animals and humans. These plasmids may play an environmental role in initiating death in vertebrates, leading to decomposition and nutrient recycling of animal biomass.
REFERENCE:
Nawrocki EM, et al. Botulinum neurotoxin–encoding plasmids can be conjugatively transferred to diverse clostridial strains. Sci Rep. 2018; 8: 3100. Published online 2018 Feb 15. doi:  10.1038/s41598-018-21342-9.

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lunes, 26 de febrero de 2018

Evaluating the Sporicidal Activity of Disinfectants against #Clostridium difficile and Bacillus amyloliquefaciens Spores

Spore-forming pathogenic bacteria, such as Clostridium difficile, are associated with nosocomial infection, leading to the increased use of sporicidal disinfectants, which impacts socioeconomic costs. However, C. difficile can be prevented using microorganisms such as Bacillus amyloliquefaciens, a prophylactic agent that has been proven to be effective against it in recent tests or it can be controlled by sporicidal disinfectants. These disinfectants against spores should be evaluated according to a known and recommended standard. Unfortunately, some newly manufactured disinfectants like Bioxy products have not yet been tested. ASTM E2197-11 is a standard test that uses stainless steel disks (1 cm in diameter) as carriers, and the performance of the test formulation is calculated by comparing the number of viable test organisms to that on the control carriers. Surface tests are preferable for evaluating disinfectants with sporicidal effects on hard surfaces. This study applies improved methods, based on the ASTM E2197-11 standard, for evaluating and comparing the sporicidal efficacies of several disinfectants against spores of C. difficile and B. amyloliquefaciens, which are used as the test organisms. With the improved method, all spores were recovered through vortexing and membrane filtration. The results show that chlorine-based products are effective in 5 min and Bioxy products at 5% w/v are effective in 10 min. Although Bioxy products may take longer to prove their effectiveness, their non-harmful effects to hospital surfaces and people have been well established in the literature.

REFERENCE:
Uwamahoro MC et al. Evaluating the Sporicidal Activity of Disinfectants against Clostridium difficile and Bacillus amyloliquefaciens Spores by Using the Improved Methods Based on ASTM E2197-11. Public Health. 2018; 6: 18. Published online 2018 Feb 5. doi:  10.3389/fpubh.2018.00018

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miércoles, 21 de febrero de 2018

Containment Studies of Transgenic Mosquitoes in Disease Endemic Countries

Genetic strategies for large scale pest or vector control using modified insects are not yet operational in Africa, and currently rely on import of the modified strains to begin preliminary, contained studies. Early involvement of research teams from participating countries is crucial to evaluate candidate field interventions. Following the recommended phased approach for novel strategies, evaluation should begin with studies in containment facilities. Experiences to prepare facilities and build international teams for research on transgenic mosquitoes revealed some important organizing themes underlying the concept of "facilities readiness," or the point at which studies in containment may proceed, in sub-Saharan African settings. First, "compliance" for research with novel or non-native living organisms was defined as the fulfillment of all legislative and regulatory requirements. This is not limited to regulations regarding use of transgenic organisms. Second, the concept of "colony utility" was related to the characteristics of laboratory colonies being produced so that results of studies may be validated across time, sites, and strains or technologies; so that the appropriate candidate strains are moved forward toward field studies. Third, the importance of achieving "defensible science" was recognized, including that study conclusions can be traced back to evidence, covering the concerns of various stakeholders over the long term. This, combined with good stewardship of resources and appropriate funding, covers a diverse set of criteria for declaring when "facilities readiness" has been attained. It is proposed that, despite the additional demands on time and resources, only with the balance of and rigorous achievement of each of these organizing themes can collaborative research into novel strategies in vector or pest control reliably progress past initial containment studies.
REFERENCE:
Quinlan MM, et al. Containment Studies of Transgenic Mosquitoes in Disease Endemic Countries: The Broad Concept of Facilities Readiness. Vector Borne Zoonotic Dis. 2018 Jan;18(1):14-20. doi: 10.1089/vbz.2017.2189. PubMed PMID: 29337664; PubMed Central PMCID: PMC5770120.

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miércoles, 14 de febrero de 2018

NOM-018-STPS-2015, Sistema armonizado para la identificación de sustancias químicas peligrosas

Objetivo
Establecer los requisitos para disponer en los centros de trabajo del sistema armonizado de identificación y comunicación de peligros y riesgos por sustancias químicas peligrosas, a fin de prevenir daños a los trabajadores y al personal que actúa en caso de emergencia.
Campo de aplicación
La presente Norma Oficial Mexicana rige en todo el territorio nacional y aplica a todos los centros de trabajo donde se manejen sustancias químicas peligrosas.
No aplica a productos terminados tales como: farmacéuticos, aditivos alimenticios, artículos cosméticos, residuos de plaguicidas en los alimentos y residuos peligrosos.
REFERENCIA:
NORMA Oficial Mexicana NOM-018-STPS-2015, Sistema armonizado para la identificación y comunicación de peligros y riesgos por sustancias químicas peligrosas en los centros de trabajo.

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lunes, 12 de febrero de 2018

Preparation of Containment Facilities for Studies of Transgenic Mosquitoes

Novel approaches to area-wide control of vector species offer promise as additional tools in the fight against vectored diseases. Evaluation of transgenic insect strains aimed at field population control in disease-endemic countries may involve international partnerships and should be done in a stepwise approach, starting with studies in containment facilities. The preparations of both new-build and renovated facilities are described, including working with local and national regulations regarding land use, construction, and biosafety requirements, as well as international guidance to fill any gaps in regulation. The examples given are for containment categorization at Arthropod Containment Level 2 for initial facility design, classification of wastes, and precautions during shipping. Specific lessons were derived from preparations to evaluate transgenic (non-gene drive) mosquitoes in West and East African countries. Documented procedures and the use of a non-transgenic training strain for trial shipments and culturing were used to develop competence and confidence among the African facility staff, and along the chain of custody for transport. This practical description is offered to support other research consortia or institutions preparing containment facilities and operating procedures in conditions where research on transgenic insects is at an early stage.
REFERENCE:
MM Quinlan et al. Studies of Transgenic Mosquitoes in Disease-Endemic Countries: Preparation of Containment Facilities. Borne Zoonotic Dis. 2018 Jan 1; 18(1): 21–30. Published online 2018 Jan 1. doi:  10.1089/vbz.2017.2192

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viernes, 9 de febrero de 2018

Detection of antimicrobial resistance in the International Space Station surface

Antimicrobial resistance (AMR) is a global health issue. In an effort to minimize this threat to astronauts, who may be immunocompromised and thus at a greater risk of infection from antimicrobial resistant pathogens, a comprehensive study of the ISS “resistome’ was conducted. Using whole genome sequencing (WGS) and disc diffusion antibiotic resistance assays, 9 biosafety level 2 organisms isolated from the ISS were assessed for their antibiotic resistance. Molecular analysis of AMR genes from 24 surface samples collected from the ISS during 3 different sampling events over a span of a year were analyzed with Ion AmpliSeq™ and metagenomics. Disc diffusion assays showed that Enterobacter bugandensis strains were resistant to all 9 antibiotics tested and Staphylococcus haemolyticus being resistant to none. Ion AmpliSeq™ revealed that 123 AMR genes were found, with those responsible for beta-lactam and trimethoprim resistance being the most abundant and widespread. Using a variety of methods, the genes involved in antimicrobial resistance have been examined for the first time from the ISS. This information could lead to mitigation strategies to maintain astronaut health during long duration space missions when return to Earth for treatment is not possible.
REFERENCE:
Urbaniak C, et al. Detection of antimicrobial resistance genes associated with the International Space Station environmental surfaces. Sci Rep. 2018; 8: 814. doi:  10.1038/s41598-017-18506-4

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miércoles, 7 de febrero de 2018

Rapid deployment of a mobile biosafety level-3 laboratory in Sierra Leone during the 2014 #Ebola virus epidemic

A Mobile Biosafety Level-3 Laboratory (MBSL-3 Lab) and a well-trained diagnostic team were dispatched to Sierra Leone to assist in Ebola virus disease (EVD) diagnosis when the largest outbreak of EVD to date emerged in West Africa in 2014. This setup allowed for the diagnosis of suspected EVD cases in less than 4 hours from the time of sample receiving. The laboratory was composed of three container vehicles and was equipped with advanced ventilation system, communication system, electricity and gas supply system. Multiple safety precautions were strictly applied to reduce exposure risks. A total of 1,635 suspected EVD cases were evaluated from September 28 to November 11, 2014, and none of the staff members was infected with Ebola virus or other pathogens. The China mobile laboratory was thus instrumental in the EVD outbreak response by providing timely and accurate diagnostics. Therefore, the MBSL-3 Lab played a significant role in establishing a suitable laboratory response capacity during the emergence of EVD in Sierra Leone.

REFERENCE:
Zhang, Yi et al. “Rapid Deployment of a Mobile Biosafety Level-3 Laboratory in Sierra Leone during the 2014 Ebola Virus Epidemic.” Ed. Brian Bird. PLoS Neglected Tropical Diseases 11.5 (2017): e0005622. PMC. Web. 4 Jan. 2018.


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lunes, 5 de febrero de 2018

Assessing infection control practices to protect health care workers and patients

Transmission of Mycobacterium tuberculosis (TB) in health settings threatens health care workers and people living with HIV in sub-Saharan Africa. Nosocomial transmission is reduced with implementation of infection control (IC) guidelines. The objective of this study is to describe implementation of TB IC measures in Malawi. We conducted a cross-sectional study utilizing anonymous health worker questionnaires, semi-structured interviews with facility managers, and direct observations at 17 facilities in central Malawi. Of 592 health care workers surveyed, 34% reported that all patients entering the facility were screened for cough and only 8% correctly named the four most common signs and symptoms of TB in adults. Of 33 managers interviewed, 7 (21%) and 1 (3%) provided the correct TB screening questions for use in adults and children, respectively. Of 592 health workers, only 2.4% had been screened for TB in the previous year. Most (90%) reported knowing their HIV status, 53% were tested at their facility of employment, and half reported they would feel comfortable receiving ART or TB treatment at their facility of employment. We conclude that screening is infrequently conducted and knowledge gaps may undercut its effectiveness. Further, health care workers do not routinely access TB and HIV diagnostic and treatment services at their facility of employment.
REFERENCE:
Flick, Robert J. et al. “Assessing Infection Control Practices to Protect Health Care Workers and Patients in Malawi from Nosocomial Transmission of Mycobacterium Tuberculosis.” Ed. Sarah L Pett. PLoS ONE 12.12 (2017): e0189140.

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