scholarly journals Multiple plasmid origin‐of‐transfer regions might aid the spread of antimicrobial resistance to human pathogens

2020 ◽  
Vol 9 (12) ◽  
Author(s):  
Jan Zrimec
2020 ◽  
Author(s):  
Jan Zrimec

AbstractAntimicrobial resistance poses a great danger to humanity, in part due to the widespread horizontal transfer of plasmids via conjugation. Modeling of plasmid transfer is essential to uncovering the fundamentals of resistance transfer and for development of predictive measures to limit the spread of resistance. However, a major limitation in the current understanding of plasmids is the inadequate characterization of the DNA transfer mechanisms, which conceals the actual potential for plasmid transfer in nature. Here, we consider that the plasmid-borne origin-of-transfer substrates encode specific DNA structural properties that can facilitate finding these regions in large datasets, and develop a DNA structure-based alignment procedure for typing the transfer substrates that outperforms mere sequence-based approaches. We identify thousands of yet undiscovered DNA transfer substrates, showing that actual plasmid mobility can in fact be 2-fold higher and span almost 2-fold more host species than is currently known. Over half of all mobile plasmids contain the means to transfer between different mobility groups, which links previously confined host ranges across ecological habitats into a robust plasmid transfer network. We show that this network in fact serves to transfer antimicrobial resistance from the environmental genetic reservoirs to human pathogens, which might be an important driver of the observed rapid resistance development in humans and thus an important point of focus for future prevention measures.


Antibiotics ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 109
Author(s):  
Alexander Lammers ◽  
Michael Lalk ◽  
Paolina Garbeva

We are currently facing an antimicrobial resistance crisis, which means that a lot of bacterial pathogens have developed resistance to common antibiotics. Hence, novel and innovative solutions are urgently needed to combat resistant human pathogens. A new source of antimicrobial compounds could be bacterial volatiles. Volatiles are ubiquitous produced, chemically divers and playing essential roles in intra- and interspecies interactions like communication and antimicrobial defense. In the last years, an increasing number of studies showed bioactivities of bacterial volatiles, including antibacterial, antifungal and anti-oomycete activities, indicating bacterial volatiles as an exciting source for novel antimicrobial compounds. In this review we introduce the chemical diversity of bacterial volatiles, their antimicrobial activities and methods for testing this activity. Concluding, we discuss the possibility of using antimicrobial volatiles to antagonize the antimicrobial resistance crisis.


2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
J. M. Mutua ◽  
C. G. Gitao ◽  
L. C. Bebora ◽  
F. K. Mutua

This study was designed to determine antimicrobial resistance profiles of bacteria isolated from the nasal cavity of healthy camels. A total of 255 nasal samples (swabs) were collected in Isiolo, Samburu, and Nakuru counties, Kenya, from which 404 bacterial isolates belonging to various genera and species were recovered. The bacterial isolates included Bacillus (39.60%), coagulase-negative Staphylococcus (29.95%), Streptococcus species other than Streptococcus agalactiae (25.74%), coagulase-positive Staphylococcus (3.96%), and Streptococcus agalactiae (0.74%). Isolates were most susceptible to Gentamicin (95.8%), followed by Tetracycline (90.5%), Kanamycin and Chloramphenicol (each at 85.3%), Sulphamethoxazole (84.2%), Co-trimoxazole (82.1%), Ampicillin (78.9%), and finally Streptomycin (76.8%). This translated to low resistance levels. Multidrug resistance was also reported in 30.5% of the isolates tested. Even though the antibiotic resistance demonstrated in this study is low, the observation is significant, since the few resistant normal flora could be harboring resistance genes which can be transferred to pathogenic bacteria within the animal, to other animals’ bacteria and, most seriously, to human pathogens.


2010 ◽  
Vol 76 (5) ◽  
pp. 1375-1387 ◽  
Author(s):  
Jennifer L. Kyle ◽  
Craig T. Parker ◽  
Danielle Goudeau ◽  
Maria T. Brandl

ABSTRACT Harvesting and processing of leafy greens inherently cause plant tissue damage, creating niches on leaves that human pathogens can exploit. We previously demonstrated that Escherichia coli O157:H7 (EcO157) multiplies more rapidly on shredded leaves than on intact leaves (M. T. Brandl, Appl. Environ. Microbiol. 74:5285-5289, 2008). To investigate how EcO157 cells adapt to physicochemical conditions in injured lettuce tissue, we used microarray-based whole-genome transcriptional profiling to characterize gene expression patterns in EcO157 after 15- and 30-min exposures to romaine lettuce lysates. Multiple carbohydrate transport systems that have a role in the utilization of substrates known to be prevalent in plant cells were activated in EcO157. This indicates the availability to the human pathogen of a variety of carbohydrates released from injured plant cells that may promote its extensive growth in leaf lysates and, thus, in wounded leaf tissue. In addition, microarray analysis revealed the upregulation of numerous genes associated with EcO157 attachment and virulence, with oxidative stress and antimicrobial resistance (including the OxyR and Mar regulons), with detoxification of noxious compounds, and with DNA repair. Upregulation of oxidative stress and antimicrobial resistance genes in EcO157 was confirmed on shredded lettuce by quantitative reverse transcription-PCR. We further demonstrate that this adaptation to stress conditions imparts the pathogen with increased resistance to hydrogen peroxide and calcium hypochlorite. This enhanced resistance to chlorinated sanitizers combined with increased expression of virulence determinants and multiplication at sites of injury on the leaves may help explain the association of processed leafy greens with outbreaks of EcO157.


2018 ◽  
Author(s):  
Swapan K. Banerjee ◽  
Jeffrey M. Farber

ABSTRACTEmergence of antimicrobial resistance (AMR) in foodborne bacteria is a growing concern worldwide. AMR surveillance is a key element in understanding the implications resulting from the use of antibiotics for therapeutic as well as prophylactic needs. The emergence and spread of AMR in foodborne human pathogens is an indirect health hazard. This surveillance study reports the trend and pattern of AMR detected inVibriospecies isolated from molluscs harvested in Canada, between 2006 and 2012, against 19 commonly used antibiotics. Five common antibiotics, ampicillin, cephalothin, erythromycin, kanamycin and streptomycin, predominantly contributed to AMR including multi-drug resistance (MDR) in the molluscanVibriospp. isolated in 2006. A prospective follow-up analysis of these drugs showed a declining trend in the frequency of MDR/AMR-Vibriospp. in subsequent years until 2012. The observed decline appears to have been influenced by the specific downturn in resistance to the aminoglycosides, kanamycin and streptomycin. Frequently observed MDR/AMR-Vibriospp. in seafood is a potential health concern associated with seafood consumption. Our surveillance study provided an indication of the antibiotics that challenged the marine bacteria, sourced to Canadian estuaries, during and/or prior to the study period.


2022 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhen Shen ◽  
Christoph M. Tang ◽  
Guang-Yu Liu

AbstractBacteria can evolve rapidly by acquiring new traits such as virulence, metabolic properties, and most importantly, antimicrobial resistance, through horizontal gene transfer (HGT). Multidrug resistance in bacteria, especially in Gram-negative organisms, has become a global public health threat often through the spread of mobile genetic elements. Conjugation represents a major form of HGT and involves the transfer of DNA from a donor bacterium to a recipient by direct contact. Conjugative plasmids, a major vehicle for the dissemination of antimicrobial resistance, are selfish elements capable of mediating their own transmission through conjugation. To spread to and survive in a new bacterial host, conjugative plasmids have evolved mechanisms to circumvent both host defense systems and compete with co-resident plasmids. Such mechanisms have mostly been studied in model plasmids such as the F plasmid, rather than in conjugative plasmids that confer antimicrobial resistance (AMR) in important human pathogens. A better understanding of these mechanisms is crucial for predicting the flow of antimicrobial resistance-conferring conjugative plasmids among bacterial populations and guiding the rational design of strategies to halt the spread of antimicrobial resistance. Here, we review mechanisms employed by conjugative plasmids that promote their transmission and establishment in Gram-negative bacteria, by following the life cycle of conjugative plasmids.


2021 ◽  
Vol 10 (1) ◽  
pp. 46
Author(s):  
Arnold Au ◽  
Helen Lee ◽  
Terry Ye ◽  
Uday Dave ◽  
Azizur Rahman

Through recent decades, the subtherapeutic use of antibiotics within agriculture has led to the widespread development of antimicrobial resistance. This problem not only impacts the productivity and sustainability of current agriculture but also has the potential to transfer antimicrobial resistance to human pathogens via the food supply chain. An increasingly popular alternative to antibiotics is bacteriophages to control bacterial diseases. Their unique bactericidal properties make them an ideal alternative to antibiotics, as many countries begin to restrict the usage of antibiotics in agriculture. This review analyses recent evidence from within the past decade on the efficacy of phage therapy on common foodborne pathogens, namely, Escherica coli, Staphylococcus aureus, Salmonella spp., and Campylobacter jejuni. This paper highlights the benefits and challenges of phage therapy and reveals the potential for phages to control bacterial populations both in food processing and livestock and the possibility for phages to replace subtherapeutic usage of antibiotics in the agriculture sector.


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