scholarly journals Towards a better understanding of antimicrobial resistance dissemination: what can be learnt from studying model conjugative plasmids?

2022 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhen Shen ◽  
Christoph M. Tang ◽  
Guang-Yu Liu
Keyword(s):  
Antimicrobial Resistance ◽  
Rational Design ◽  
Global Public Health ◽  
Human Pathogens ◽  
Bacterial Populations ◽  
Gram Negative ◽  
Conjugative Plasmids ◽  
Defense Systems ◽  
Metabolic Properties ◽  
Gram Negative Organisms

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.

Antimicrobial Resistance in the Intensive Care Unit

2016 ◽  
Vol 32 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Shawn H. MacVane
Keyword(s):  
Intensive Care ◽  
Antimicrobial Resistance ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Treatment Options ◽  
Hospital Costs ◽  
High Morbidity ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Gram Negative Organisms

Bacterial infections are a frequent cause of hospitalization, and nosocomial infections are an increasingly common condition, particularly within the acute/critical care setting. Infection control practices and new antimicrobial development have primarily focused on gram-positive bacteria; however, in recent years, the incidence of infections caused by gram-negative bacteria has risen considerably in intensive care units. Infections caused by multidrug-resistant (MDR) gram-negative organisms are associated with high morbidity and mortality, with significant direct and indirect costs resulting from prolonged hospitalizations due to antibiotic treatment failures. Of particular concern is the increasing prevalence of antimicrobial resistance to β-lactam antibiotics (including carbapenems) among Pseudomonas aeruginosa and Acinetobacter baumannii and, recently, among pathogens of the Enterobacteriaceae family. Treatment options for infections caused by these pathogens are limited. Antimicrobial stewardship programs focus on optimizing the appropriate use of currently available antimicrobial agents with the goals of improving outcomes for patients with infections caused by MDR gram-negative organisms, slowing the progression of antimicrobial resistance, and reducing hospital costs. Newly approved treatment options are available, such as β-lactam/β-lactamase inhibitor combinations, which significantly extend the armamentarium against MDR gram-negative bacteria.

scholarly journals Microbial Contamination and Antimicrobial Resistance in Use of Ophthalmic Solutions at the Department of Ophthalmology, Jimma University Specialized Hospital, Southwest Ethiopia

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Lemlem Tamrat ◽  
Yeshigeta Gelaw ◽  
Getenet Beyene ◽  
Addisu Gize
Keyword(s):  
Antimicrobial Resistance ◽  
Eye Drops ◽  
Southwest Ethiopia ◽  
Gram Negative ◽  
Microbial Identification ◽  
Specialized Hospital ◽  
Department Of Ophthalmology ◽  
Gram Negative Organisms ◽  
Ophthalmic Solutions ◽  
Jimma University

Background. Eye drops are most frequently used medications in ophthalmology. The carriage of pathogenic organisms to eyes through the agency of eye drops has presented a serious problem for several decades. The objective of this study was to determine the magnitude of contamination and pattern of antimicrobial resistance of in-use ophthalmic solutions. Method. A cross-sectional study was conducted at the Department of Ophthalmology, Jimma University Specialized Hospital (JUSH), Southwest Ethiopia, from June to December 2015. Samples from all ophthalmic solutions from outpatient department, operation theaters, and wards after an average duration of use of two weeks were taken. Samples were cultured and organisms were identified; antimicrobial susceptibility testing was performed using standard microbial identification techniques. The data were analyzed using SPSS software. Chi-square test was done and associations were taken as significant if P<0.05. Result. The rate of contamination of eye drops in the study setup was found to be 51/70 (72.8%). Frequency of contamination of eye drops found was to be statistically associated with the duration of use of eye drops. Contaminations of eye drops were high among patients who self-administer the medications and those individuals who apply the medication less frequently. Tips of the bottles were more often contaminated than the content of the eye drop. Majority of both Gram-positive and Gram-negative organisms were sensitive for most of the broad-spectrum antibiotics; however, there were a significant number of Gram-negative organisms resistant to almost all antibiotics used. Conclusion. There is high rate of contamination of eye drops in the setup (72.8%). Duration of use of eye drops is a significant factor associated with contamination. Knowing duration time of each container and patient education on eye drop administration technique are mandatory.

scholarly journals Canadian Patterns of Antimicrobial Resistance: Overview of Current Trends Related to Hospital Pathogens

2006 ◽  
Vol 17 (suppl b) ◽  
pp. 3B-5B
Author(s):  
Tony Mazzulli
Keyword(s):  
Antimicrobial Resistance ◽  
Methicillin Resistance ◽  
Geographical Location ◽  
Current Data ◽  
Control Measures ◽  
Infection Prevention And Control ◽  
Gram Negative ◽  
Canadian Data ◽  
Gram Negative Organisms ◽  
Resistance Rates

Selection of appropriate empirical antibiotic therapy is dependent on many factors, not the least of which is an understanding of antimicrobial resistance rates in the patient population that is undergoing treatment. Resistance rates may vary by geographical location, institution, hospital ward or unit, and even body site of infection. The present paper reviews the currently available Canadian data regarding resistance rates for some of the most common hospital-acquired pathogens, includingEscherichia coli,Klebsiellaspecies,Pseudomonas aeruginosa,Enterobacterspecies,Staphylococcus aureusandEnterococcusspecies. Current data suggest that the rates of extended-spectrum beta-lactamases amongE coliandKlebsiellaspecies remain relatively low across Canada. There are very little data on the epidemiology of ampC cephalosporinases among Gram-negative organisms, although combined American and Canadian data suggest that ceftazidime resistance rates forEnterobacterspecies range from 17.1% to 24.8%. The increased use of fluoroquinolones has led to an increase in resistance rates among most Gram-negative organisms. In the late 1990s, ciprofloxacin resistance rates forP aeruginosawere reported to be approximately 20%. For the Gram-positive organisms, methicillin resistance rates forS aureushave been reported to be as high as 10% and vancomycin resistance rates forEnterococcusspecies have been reported to be less than 1%. Additional data that are representative of all regions of Canada are needed. Continued surveillance, antibiotic stewardship, and adherence to good infection prevention and control measures will lead to a better understanding of the epidemiology of antimicrobial resistance in Canadian hospitals, as well as help to control its spread.

Intrinsic, adaptive and acquired antimicrobial resistance in Gram-negative bacteria

2017 ◽  
Vol 61 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Mohsen Arzanlou ◽  
Wern Chern Chai ◽  
Henrietta Venter
Keyword(s):  
Antimicrobial Resistance ◽  
Molecular Mechanisms ◽  
Resistance Mechanisms ◽  
Stress Conditions ◽  
Gram Negative Bacteria ◽  
Mechanisms Of Resistance ◽  
Intrinsic Resistance ◽  
Antimicrobial Drugs ◽  
Gram Negative ◽  
Gram Negative Organisms

Gram-negative bacteria are responsible for a large proportion of antimicrobial-resistant infections in humans and animals. Among this class of bacteria are also some of the most successful environmental organisms. Part of this success is their adaptability to a variety of different niches, their intrinsic resistance to antimicrobial drugs and their ability to rapidly acquire resistance mechanisms. These mechanisms of resistance are not exclusive and the interplay of several mechanisms causes high levels of resistance. In this review, we explore the molecular mechanisms underlying resistance in Gram-negative organisms and how these different mechanisms enable them to survive many different stress conditions.

Infections due to Escherichia coli and Other Enteric Gram-Negative Bacilli

2016 ◽  
Author(s):  
Allison Mah ◽  
Inna Sekirov ◽  
Theodore S Steiner
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Tract ◽  
Antimicrobial Resistance ◽  
Clinical Manifestations ◽  
Gram Negative ◽  
The Family ◽  
Enteric Infections ◽  
Gram Negative Organisms ◽  
Tract Infections

This review describes infections caused by Escherichia coli and related members of the family Enterobacteriaceae, excluding other genera that principally cause enteric infections. Infections caused by Salmonella, Shigella, and Yersinia are described in the review “Gastrointestinal Tract Infections," found elsewhere in this publication. The purpose of this review is to examine the specific epidemiology, clinical manifestations, and treatment of individual members of the Enterobacteriaceae. The emerging concern of antimicrobial resistance amongst enteric gram-negative organisms and the approach to treatment in the setting of infection with these resistant organisms are discussed in the review “Antimicrobial Resistance in Enteric Gram-Negative Organisms,” found elsewhere in this publication. Figures illustrate the mechanisms of antimicrobial resistance in Enterobacteriaceae. A table lists the clinical, epidemiologic, pathogenetic, and therapeutic aspects of infection with various pathotypes of Escherichia coli. This review contains 6 highly rendered figures, 1 table, and 79 references.

scholarly journals Bdellovibrio Predation in the Presence of Decoys: Three-Way Bacterial Interactions Revealed by Mathematical and Experimental Analyses

2006 ◽  
Vol 72 (10) ◽  
pp. 6757-6765 ◽  
Author(s):  
Laura Hobley ◽  
John R. King ◽  
R. Elizabeth Sockett
Keyword(s):  
Natural Environments ◽  
Human Pathogens ◽  
Bacterial Populations ◽  
Gram Negative ◽  
Predator Prey ◽  
Positive Effects ◽  
Complex Interactions ◽  
Predation Efficiency ◽  
Pure Cultures ◽  
Final Yield

ABSTRACT Bdellovibrio bacteriovorus is a small, gram-negative, motile bacterium that preys upon other gram-negative bacteria, including several known human pathogens. Its predation efficiency is usually studied in pure cultures containing solely B. bacteriovorus and a suitable prey. However, in natural environments, as well as in any possible biomedical uses as an antimicrobial, Bdellovibrio is predatory in the presence of diverse decoys, including live nonsusceptible bacteria, eukaryotic cells, and cell debris. Here we gathered and mathematically modeled data from three-member cultures containing predator, prey, and nonsusceptible bacterial decoys. Specifically, we studied the rate of predation of planktonic late-log-phase Escherichia coli S17-1 prey by B. bacteriovorus HD100, both in the presence and in the absence of Bacillus subtilis nonsporulating strain 671, which acted as a live bacterial decoy. Interestingly, we found that although addition of the live Bacillus decoy did decrease the rate of Bdellovibrio predation in liquid cultures, this addition also resulted in a partially compensatory enhancement of the availability of prey for predation. This effect resulted in a higher final yield of Bdellovibrio than would be predicted for a simple inert decoy. Our mathematical model accounts for both negative and positive effects of predator-prey-decoy interactions in the closed batch environment. In addition, it informs considerations for predator dosing in any future therapeutic applications and sheds some light on considerations for modeling the massively complex interactions of real mixed bacterial populations in nature.

scholarly journals Bacteriophages: Combating Antimicrobial Resistance in Food-Borne Bacteria Prevalent in Agriculture

2021 ◽  
Vol 10 (1) ◽  
pp. 46
Author(s):  
Arnold Au ◽  
Helen Lee ◽  
Terry Ye ◽  
Uday Dave ◽  
Azizur Rahman
Keyword(s):  
Antimicrobial Resistance ◽  
Foodborne Pathogens ◽  
Phage Therapy ◽  
Human Pathogens ◽  
Salmonella Spp ◽  
Bacterial Populations ◽  
Bacterial Diseases ◽  
Agriculture Sector ◽  
Food Borne ◽  
Bactericidal Properties

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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