Suchergebnisse

Multidrug-resistant bacteria have on overwhelming impact on human health, as they cause over 670,000 infections and 33,000 deaths annually in the European Union alone. Of these, the vast majority of infections and deaths are caused by only a handful of species—multi-drug resistant Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus spp., Acinetobacter spp. and Klebsiella pneumoniae. These pathogens employ a multitude of antibiotic resistance mechanisms, such as the production of antibiotic deactivating enzymes, changes in antibiotic targets, or a reduction of intracellular antibiotic concentration, which render them insusceptible to multiple antibiotics. The purpose of this review is to summarize in a clinical manner the resistance mechanisms of each of these 6 pathogens, as well as the mechanisms of recently developed antibiotics designed to overcome them. Through a basic understanding of the mechanisms of antibiotic resistance, the clinician can better comprehend and predict resistance patterns even to antibiotics not reported on the antibiogram and can subsequently select the most appropriate antibiotic for the pathogen in question.

Antibiotics revolutionized modern medicine and have been an excellent tool to fight infections. However, their overuse and misuse in different human activities such as health care, food production and agriculture has resulted in a global antimicrobial resistance crisis. Some regions such as Latin America present a more complex scenario because of the lack of resources, systematic studies and legislation to control the use of antimicrobials, thus increasing the spread of antibiotic resistance. This review aims to summarize the state of environmental antibiotic resistance in Latin America, focusing on water resources. Three databases were searched to identify publications on antimicrobial resistance and anthropogenic activities in relation to natural and artificial water ecosystems. We found that antibiotic resistant bacteria, mainly against beta lactam antibiotics, have been reported in several Latin American countries, and that resistant bacteria as well as resistant genes can be isolated from a wide variety of aquatic environments, including drinking, surface, irrigation, sea and wastewater. It is urgent to establish policies and regulations for antibiotic use to prevent the increase of multi-drug resistant microorganisms in the environment.

Abstract
Background
Environmental hygiene concerns are needed to be settled before the reuse of abandoned swine feedlot sites. However, few researchers have focused on the fate of antibiotic resistance genes (ARGs) in soil microbiota around abandoned swine feedlots. In this study, we examined the seasonal alterations of ARGs and bacterial community composition in soil using quantitative PCR and high-throughput sequencing of 16S rRNA gene.

Results
The seasonal variation patterns were different for different ARG subtypes and soil sampling sites. The bacterial community composition at the genus level generally showed no significant alteration from winter to summer. Moreover, the co-occurrence network suggested that the bacterial genera host range of ARGs was broader in the summer than in the winter.

Conclusion
This study offers further data on ARG transfer risk in soil, emphasizing the necessity of continuous concern before land-reuse of abandoned feedlots.

Water bodies worldwide have proven to be vast reservoirs of clinically significant antibiotic resistant organisms. Contamination of waters by anthropogenic discharges is a significant contributor to the widespread dissemination of antibiotic resistance. The aim of this research was to investigate multiple different anthropogenic sources on a national scale for the role they play in the environmental propagation of antibiotic resistance. A total of 39 water and 25 sewage samples were collected across four local authority areas in the West, East and South of Ireland. In total, 211 Enterobacterales were isolated (139 water, 72 sewage) and characterised. A subset of isolates (n=60) were chosen for whole genome sequencing. Direct comparisons of the water versus sewage isolate collections revealed a higher percentage of sewage isolates displayed resistance to cefoxitin (46%) and ertapenem (32%), while a higher percentage of water isolates displayed resistance to tetracycline (55%) and ciprofloxacin (71%). Half of all isolates displayed extended spectrum beta-lactamase (ESBL) production phenotypically (n = 105/211; 50%), with blaCTX-M detected in 99/105 isolates by PCR. Carbapenemase genes were identified in 11 isolates (6 sewage, 5 water). The most common variant was blaOXA-48 (n=6), followed by blaNDM-5 (n=2) and blaKPC-2 (n=2). Whole genome sequencing analysis revealed numerous different sequence types in circulation in both waters and sewage including E. coli ST131 (n=15), ST38 (n=8), ST10 (n=4) along with Klebsiella ST405 (n=3) and ST11 (n=2). Core genome MLST (cgMLST) comparisons uncovered three highly similar Klebsiella isolates originating from hospital sewage and two nearby waters. The Klebsiella isolates from an estuary and seawater displayed 99.1% and 98.8% cgMLST identity to the hospital sewage isolate respectively. In addition, three pairs of E. coli isolates from different waters also revealed cgMLST similarities, indicating widespread dissemination and persistence of certain strains in the aquatic environment. These findings highlight the need for routine monitoring of water bodies used for recreational and drinking purposes for the presence of multi-drug resistant organisms. ; This project is jointly funded by the Environmental Protection agency, under the EPA Research Programme 2014-2020, and the Health Service Executive (2017-HW-LS-1). The EPA Research Programme is a Government of Ireland initiative funded by the Department of Communications, Climate Action and Environment. It is administered by the Environmental Protection Agency, which has the statutory function of co-ordinating and promoting environmental research. A portion of this work was also financially supported by the MedVetKlebs project, a component of the European Joint Programme One Health EJP, which has received funding from the European Union's Horizon 2020 Research and Innovation Programme under Grant Agreement No. 773830. ; peer-reviewed

Beef preparations (meatballs, minced meat, hamburgers, white sausages, and red sausages) from northwest Spain were tested. Microbial counts ranged from 0.70 ± 0.00 log10 cfu/g (enterococci) to 9.57 ± 0.37 log10 cfu/g (psychrotrophs). In 73.3% of cases, total aerobic counts were higher than the microbiological limits set for the end of the manufacturing process in the European Union (EU Regulation 2073/2005). Forty Escherichia coli isolates were tested against thirteen clinically important antibiotics (disk diffusion method; CLSI). Three of the strains (7.5%) were susceptible to all the antibiotics, four (10.0%) showed resistance or reduced susceptibility to one antibiotic, and 33 (82.5%) were multiresistant (with resistance or reduced susceptibility to between two and eight antibiotics), with an average of 1.85 resistances per strain. The highest rates of resistance were observed for two antimicrobials widely used on cattle farms (cefalotin and tetracycline). The findings in this research emphasize the need to correctly handle beef preparations with the aim of reducing risks to consumers.

The current study was carried out to detect Salmonella spp. contamination on chicken carcasses and to determine the antibiotic susceptibility profiles and serotype distribution of the isolates. A total of 200 packaged fresh raw chicken samples sold at retail in different markets in central Anatolia were analysed between April 2005 and March 2006. Salmonella spp. was detected in 34% (68/200) of samples using cultural technique and were confirmed by PCR. Ten Salmonella serovars were identified; predominant ones included Typhimurium, Infantis and Heidelberg. All of the Salmonella spp. isolates tested, exhibited resistance to one or more antimicrobial agents used. Resistance to penicillin, oxacillin, clindamycin, vancomycin, erythromycin and ampicillin were evident 100%, 97%, 97%, 92.6%, 89.7% and 85.2%, respectively. Also resistance to tetracycline (67.6%), streptomycin (61.7%), neomycin (55.8%) and cephalothin (52.9%) was observed but a small percentage of the isolates demonstrated resistance to gentamicin (14.7%), chloramphenicol (10.2%), cefotaxime (2.9%) and amikacin (2.9%). As a result, high prevalence of Salmonella spp. and the relatively high resistance among the bacteria tested could pose public health and therapeutic problems in consumers as potential vehicle of resistant Salmonella foodborne infections. To avoid Salmonella contamination, hygienic rules of slaughter and poultry meat processing must be rigorously observed and antibiotic use must be controlled by governmental agencies to prevent increased resistance of antibiotics. © 2010 Elsevier Ltd.

Abstract
Background
The prevalence of antibiotic resistance genes (ARGs) in animal manure poses a threat to environmental safety. Organic fertilizers fermented by livestock and poultry manure are directly applied to farmland and have the potential to cause outbreaks of bacterial resistance in agricultural environments. This study investigated the composition of ARGs in different animal manures and their derived organic fertilizers.

Results
The results showed that the abundance of several ARGs, such as sul2, TetB-01, TetG-01 and TetM-01, in organic fertilizer samples was 12–96% lower than that in animal manure. However, the abundance of TetK and ermC was higher in animal manure than in organic fertilizers. No correlation between ARGs and environmental factors such as pH, TN, and antibiotics was observed by redundancy analysis (RDA). Procrustes analysis revealed a significant correlation between bacterial community structures and ARG abundance (r = 0.799, p < 0.01). Nonmetric multidimensional scaling (NMDS) analysis suggested that microorganisms in organic fertilizer may be derived from animal manure. Additionally, the abundance of pathogenic bacteria (especially Actinomadura) would increase rather than decrease in manure compared to organic fertilizer.

Conclusion
The diversity and abundance of most ARGs significantly decreased from animal manure to organic fertilizer. Microorganisms in the prepared organic fertilizer may mainly be inherited from the animal manure. The results also showed that the pathogens in the prepared organic fertilizer would significantly reduce, but would still cause partial pathogen proliferation.

The authors present climate change and antibiotic resistance as emergent biosocial phenomena—ongoing products of massively multiple interactions among human lifestyles and broader life processes. They argue that response to climate change and antibiotic resistance is often framed by two varieties of biosocial imagination. Anthropocentric imaginations privilege the question of human distinctiveness. Anthropomorphic imaginations privilege the question of whether biosocial processes can be modeled in terms of centers of moral and causal responsibility. Together, these frame the matter of response in terms of deliberate human action. The authors argue that, considered as emergent biosocial phenomena, climate change and antibiotic resistance "diffract" deliberate human action and thus limit the value of this frame by rendering the human/nonhuman and intended/nonintended distinctions that are crucial to its practical operation locally irrelevant. Alternative biosocial imaginations currently developing around climate change and antibiotic resistance that allow for "diffraction" and therefore frame response differently are considered.

Antibiotic resistance is a worldwide concern that requires a concerted action from physicians, patients, governmental agencies, and academia to prevent infections and the spread of resistance, track resistant bacteria, improve the use of current antibiotics, and develop new antibiotics. Despite the efforts spent so far, the current antibiotics in the market are restricted to only five general targets/pathways highlighting the need for basic research focusing on the discovery and evaluation of new potential targets. Here we interrogate two biosynthetic pathways as potentially druggable pathways in bacteria. The biosynthesis pathway for thiamine (vitamin B1), absent in humans, but found in many bacteria, including organisms in the group of the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter sp.) and the biosynthesis pathway for pyridoxal 5′-phosphate and its vitamers (vitamin B6), found in S. aureus. Using current genomic data, we discuss the possibilities of inhibition of enzymes in the pathway and review the current state of the art in the scientific literature.