1,720,962 research outputs found
MOLECULAR EPIDEMIOLOGY OF EMERGING ANTIBIOTIC RESISTANCE MECHANISMS IN COMMENSAL AND PATHOGENIC BACTERIA IN LATIN AMERICA
Full text linkBacterial resistance to antibiotics is a major public health problem, and the increasing spread of multi-resistant isolates represents an alarming challenge due to the limited treatment options for infections caused by these pathogens.
This phenomenon is an important concern in low resource countries like those of Latin America, where the combination of factors such as inefficient health systems, poor sanitation and uncontrolled use of antimicrobials provide conditions to develop and maintain resistant strains in the hospital settings, at the community level and in the environment.
In this work, was analysed the molecular epidemiology of emerging antibiotic resistance mechanisms in commensal and pathogenic bacteria from Latin America.
In particular, the study on the antimicrobial susceptibility of clinical isolates from urinary tract infections in Bolivia allowed to gather insight into the mechanisms of dissemination of emerging resistance determinants of clinical significance (such as CTX-M, RmtB, FOSA3), emphasizing the role of high-risk clones in the dissemination of antimicrobial resistance determinants.
The same burning phenomenon can be observed in Argentina, where the dissemination of successful clones, responsible for the diffusion of CTX-M and AAC(6’)-Ib-cr determinants in clinical settings, has partially contributed to the change of ESBL epidemiology in this country.
Furthermore the finding of the F33:A-:B- epidemic plasmid (widely disseminated among animals in China) in clinical isolates in Bolivia confirm the role of animals as reservoir of multiresistance bacteria. The routes of spreading of such plasmids are unclear and would deserve further investigation, even though the increasing frequency of international travel and the intensive intercontinental commerce could be an easy way for the circulation of resistant strains.
Similarly to pathogenic bacteria, commensals are exposed to the selective pressure of antimicrobial drugs. This exposure may have long-term effects on commensal microbiota, which may evolve in an important reservoir of antibiotic resistant strains potentially transferable to pathogens. Therefore, commensal bacteria are considered indicator in predicting the dissemination of resistance among pathogens. Indeed, surveillance is considered crucial for the implementation of intervention strategies aimed at preserving the efficacy of antimicrobial chemotherapy.
Surveillance studies performed on commensal bacteria in healthy children from urban areas of Bolivia and Peru provided new information regarding the dynamics of emergence and dissemination of clinically relevant resistance phenotypes, included those associated to CTX-M and Qnr determinants.
To investigate the correlation between resistance rates observed in the microbiota of healthy individuals and in the pathogens circulating in the same setting, we have started collaborating with two hospitals that have recently implemented microbiological diagnosis for UTIs (urinary tract infections) and SSTIs (skin and soft-tissues infections).
In this regard, first data concerning the comparison between S. aureus from colonization and infection revealed the circulation of the same clones among carriers and patients. These findings underscore that surveillance of antimicrobial resistance on commensal microbiota can be useful to guide empiric management of infections, especially in settings where microbiological diagnosis is not available.
In conclusion, the problem of antimicrobial resistance in Latin America, although a regional challenge, deserves international efforts. Multidisciplinary and collaborative efforts should be made to tackle antibiotic resistance and to achieve “One Health” that is a global health for people, animals and the environment.
Investments in education, public health and sanitation, development of guidelines for strategic antibiotic use, attempts to facilitate the access to rapid diagnostic tools, implementation of effective and internationally connected resistance surveillance programs and strict control and transparency in the antimicrobial supply chain are some examples of measures that could help to decelerate de advance of the antimicrobial resistance in low resource countries
pHN7A8-related multiresistance plasmids (blaCTX-M-65, fosA3 and rmtB) detected in clinical isolates of Klebsiella pneumoniae from Bolivia: Intercontinental plasmid dissemination?
No full textSynergistic activity profile of an antimicrobial peptide against multidrug-resistant and extensively drug-resistant strains of Gram-negative bacterial pathogens
No full textInfection sustained by multidrug-resistant and extensively drug-resistant bacterial pathogens is often untreatable with the standard of care antibiotics, and the combination of anti-infective compounds often represents the only therapeutic strategy to face this major clinical treat. SET-M33 is a novel antimicrobial peptide (AMP) that has demonstrated in vitro and in vivo antimicrobial activity against Gram-negative bacteria and has shown interesting features in preclinical evaluations. Particularly, it showed efficacy against a number of multidrug-resistant and extensively drug-resistant clinical strains of Gram-negative pathogens, in in vitro and in vivo assessments. Here, we explored the potential synergistic activity of SET-M33 in combination with different standard of care antibiotics by the checkerboard method against a panel of six strains of Gram-negative pathogens including multidrug-resistant and extensively drug-resistant Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. SET-M33 showed synergistic activity with antibiotics of different families against these clinically relevant strains. A synergistic effect was observed for SET-M33 in combination with rifampin, meropenem, aztreonam, and tobramycin mostly on K. pneumoniae and A. baumannii strains, while the SET-M33 plus ciprofloxacin combination was additive with all tested strains. Synergy was not apparently linked to the bacterial species or phenotype but was rather strain-specific, highlighting the need for individual strain testing for synergistic antimicrobial combinations. These findings extend current knowledge on synergistic activity of AMPs in combination with conventional agents and support the potential role of SET-M33 as a novel therapeutic agent against antibiotic-resistant Gram-negative pathogens
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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