scholarly journals Computational Model to Quantify the Growth of Antibiotic Resistant Bacteria in Wastewater

2020 ◽  
Author(s):  
I. Sutradhar ◽  
C. Ching ◽  
D. Desai ◽  
M. Suprenant ◽  
M. H. Zaman
Keyword(s):  
Public Health ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Drug Resistant ◽  
Antibiotic Residues ◽  
Bacterial Populations ◽  
Antibiotic Resistant ◽  
Resistant Population ◽  
Resistant Infection ◽  
Quantitative Understanding

AbstractThough wastewater and sewage systems are known to be a significant reservoir of antibiotic resistant bacterial populations and periodic outbreaks of drug resistant infection, there is little quantitative understanding of the drivers behind resistant population growth in these settings. In order to fill this gap in quantitative understanding of outbreaks of antibiotic resistant infections in wastewater, we have developed a mathematic model synthesizing many of the known drivers of antibiotic resistance in these settings in order to predict the growth of resistant populations in different environmental scenarios. A number of these drivers of drug resistant infection outbreak including antibiotic residue concentration, antibiotic interaction and synergy, chromosomal mutation and horizontal gene transfer, have not previously been integrated into a single computational model. Our integrated model shows that low levels of antibiotic residues present in wastewater can lead to the increased development of resistant populations, and the dominant mechanism of resistance acquisition in these populations is horizontal gene transfer rather than chromosomal mutations. Additionally, we found that synergistic antibiotic interactions can cause increased resistant population growth. Our study shows that the effects of antibiotic interaction are observable even at the low antibiotic concentrations present in wastewater settings. These findings, consistent with recent experimental and field studies, provide new quantitative knowledge on the evolution of antibiotic resistant bacterial reservoirs, and the model developed herein can be adapted for use as a prediction tool in public health policy making, particularly in low income settings where water sanitation issues remain widespread and disease outbreaks continue to undermine public health efforts.SignificanceThe rate at which antimicrobial resistance (AMR) has developed and spread throughout the world has increased in recent years, and it is suggested that at the current rate, several million people may die by 2050 due to AMR. One major reservoir of resistant bacterial populations that has been linked to outbreaks of drug resistant bacterial infections, but is not well understood, is in wastewater settings, where antibiotic pollution is often present. Using ordinary differential equations incorporating several known drivers of resistance in wastewater, we find that interactions between antibiotic residues and horizontal gene transfer significantly affect the growth of resistant bacterial reservoirs.

MODELING ANTIBIOTIC RESISTANCE IN PREGNANT WOMAN AND FETUS

2011 ◽  
Vol 19 (03) ◽  
pp. 505-520
Author(s):  
HAI-FENG HUO ◽  
JUN LI ◽  
YU-NING LI
Keyword(s):  
Public Health ◽  
Pregnant Woman ◽  
Transmission Dynamics ◽  
Resistant Bacteria ◽  
Uniform Persistence ◽  
Antibiotic Residues ◽  
Global Public Health ◽  
Antibiotic Resistant ◽  
Gestational Period ◽  
Potential Impact

Infection caused by antibiotic-resistant pathogens is one of global public health problems. Many factors contribute to the emergence and spread of these pathogens. A model which describes the transmission dynamics of susceptible and resistant bacteria in a pregnant woman and the fetus is presented. Detailed qualitative analysis about positivity, boundedness, global stability and uniform persistence of the model is carried out. Numerical simulation and sensitivity analysis show that antibiotic input has potential impact for neonatal drug resistance. Our results show that the resistant bacteria in baby mainly come from antibiotics which are wrongly-used during gestational period, or foods containing antibiotic residues.

scholarly journals Experimental Evolution of Bacillus subtilis Reveals the Evolutionary Dynamics of Horizontal Gene Transfer and Suggests Adaptive and Neutral Effects

Genetics ◽  
2020 ◽  
Vol 216 (2) ◽  
pp. 543-558
Author(s):  
Shai Slomka ◽  
Itamar Françoise ◽  
Gil Hornung ◽  
Omer Asraf ◽  
Tammy Biniashvili ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Evolutionary Dynamics ◽  
De Novo ◽  
Growth Yield ◽  
Genomic Variation ◽  
Bacterial Populations ◽  
Flagellar Proteins ◽  
Foreign Dna

Tracing evolutionary processes that lead to fixation of genomic variation in wild bacterial populations is a prime challenge in molecular evolution. In particular, the relative contribution of horizontal gene transfer (HGT) vs.de novo mutations during adaptation to a new environment is poorly understood. To gain a better understanding of the dynamics of HGT and its effect on adaptation, we subjected several populations of competent Bacillus subtilis to a serial dilution evolution on a high-salt-containing medium, either with or without foreign DNA from diverse pre-adapted or naturally salt tolerant species. Following 504 generations of evolution, all populations improved growth yield on the medium. Sequencing of evolved populations revealed extensive acquisition of foreign DNA from close Bacillus donors but not from more remote donors. HGT occurred in bursts, whereby a single bacterial cell appears to have acquired dozens of fragments at once. In the largest burst, close to 2% of the genome has been replaced by HGT. Acquired segments tend to be clustered in integration hotspots. Other than HGT, genomes also acquired spontaneous mutations. Many of these mutations occurred within, and seem to alter, the sequence of flagellar proteins. Finally, we show that, while some HGT fragments could be neutral, others are adaptive and accelerate evolution.

scholarly journals Demonstration of Conjugative Transposon (Tn5397)-Mediated Horizontal Gene Transfer between Clostridium difficile and Enterococcus faecalis

2010 ◽  
Vol 54 (11) ◽  
pp. 4924-4926 ◽  
Author(s):  
Azmiza S. Jasni ◽  
Peter Mullany ◽  
Haitham Hussain ◽  
Adam P. Roberts
Keyword(s):  
Gene Transfer ◽  
Clostridium Difficile ◽  
Horizontal Gene Transfer ◽  
Enterococcus Faecalis ◽  
Nosocomial Infections ◽  
Conjugative Transposon ◽  
Antibiotic Resistant ◽  
Specific Target ◽  
Ribotype 027 ◽  
Target Sites

ABSTRACT Antibiotic-resistant Enterococcus faecalis and Clostridium difficile are responsible for nosocomial infections in humans, in which they inhabit the same niche. Here, we demonstrate transfer of the conjugative transposon Tn5397 from C. difficile 630 to E. faecalis JH2-2, the first reported gene transfer between these two bacteria. Furthermore, transfer from the E. faecalis EF20A transconjugant to the epidemic ribotype 027 C. difficile strain R20291 was also demonstrated. Tn5397 was shown to use a single specific target site in E. faecalis; it also has specific target sites in C. difficile. These experiments highlight the importance of continual monitoring for emerging resistances in these bacteria.

scholarly journals The Linguistics of Bacterial Conflict Systems Reveal Ancient Origins of Eukaryotic Innate Immunity

2020 ◽  
Vol 202 (24) ◽  
Author(s):  
Emily M. Kibby ◽  
Aaron T. Whiteley
Keyword(s):  
Innate Immunity ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Evolutionary History ◽  
Protein Domains ◽  
Arms Race ◽  
Bacterial Populations ◽  
Defense Systems ◽  
History Of ◽  
Novel Protein

ABSTRACT The arms race between bacteria and their competitors has produced an astounding variety of conflict systems that are shared via horizontal gene transfer across bacterial populations. In this issue of the Journal of Bacteriology, Burroughs and Aravind investigate how these biological conflict systems have been mixed and matched into new configurations, often with novel protein domains (A. M. Burroughs and L. Aravind, J Bacteriol 202:e00365-20, 2020, https://doi.org/10.1128/JB.00365-20). The authors additionally characterize the evolutionary history of genes in eukaryotes that appear to have been acquired from these prokaryotic defense systems.

scholarly journals Drug-Resistant Infection: Causes, Consequences, and Responses

2020 ◽  
pp. 3-18
Author(s):  
Euzebiusz Jamrozik ◽  
Michael J. Selgelid
Keyword(s):  
Public Health ◽  
Drug Resistance ◽  
Well Being ◽  
Microbial Evolution ◽  
Antimicrobial Use ◽  
Drug Resistant ◽  
Genetic Determinants ◽  
Policy Responses ◽  
Hygiene Practices ◽  
Resistant Infection

Abstract This chapter provides an overview of the causes and consequences of, and possible policy responses to, the problem of drug resistance. Throughout, we highlight the ways that ethical and conceptual analyses can help to clarify relevant issues and improve policy, especially in public health, broadly conceived. Drug resistant pathogens arise, persist, spread, and produce harm due to a complex set of causes: biological processes (e.g., related to microbial evolution, the transmission of genetic determinants of resistance between microbes, and human host immunity) as well as human behaviors (e.g., antimicrobial use and hygiene practices) and other social factors (e.g., access to clean water, sanitation, healthcare, and antimicrobials). Furthermore, the ethically salient consequences of drug resistance include not only morbidity and mortality from untreatable infections (that are often inequitably distributed), but also broader effects on human freedom, privacy, and well-being. Public health ethicists are ideally placed to identify and weigh the values that might be promoted or compromised by potential policies and/or interventions that aim to address the problem of drug resistance. This chapter concludes by discussing potential policy responses, including those related to surveillance, research, animal and human antimicrobial use, the broader social determinants of health, infection control practices, and vaccination.

scholarly journals Horizontal Gene Transfer of Antibiotic Resistance from Acinetobacter baylyi to Escherichia coli on Lettuce and Subsequent Antibiotic Resistance Transmission to the Gut Microbiome

mSphere ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Marlène Maeusli ◽  
Bosul Lee ◽  
Sarah Miller ◽  
Zeferino Reyna ◽  
Peggy Lu ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Resistance Genes ◽  
Gut Microbiome ◽  
Acinetobacter Baylyi ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Plant Foods ◽  
Link Type

ABSTRACT Agricultural use of antibiotics is recognized by the U.S. Centers for Disease Control and Prevention as a major contributor to antibiotic-resistant infections. While most One Health attention has been on the potential for antibiotic resistance transmission from livestock and contaminated meat products to people, plant foods are fundamental to the food chain for meat eaters and vegetarians alike. We hypothesized that environmental bacteria that colonize plant foods may serve as platforms for the persistence of antibiotic-resistant bacteria and for horizontal gene transfer of antibiotic-resistant genes. Donor Acinetobacter baylyi and recipient Escherichia coli were cocultured in vitro, in planta on lettuce, and in vivo in BALB/c mice. We showed that nonpathogenic, environmental A. baylyi is capable of transferring plasmids conferring antibiotic resistance to E. coli clinical isolates on lettuce leaf discs. Furthermore, transformant E. coli from the in planta assay could then colonize the mouse gut microbiome. The target antibiotic resistance plasmid was identified in mouse feces up to 5 days postinfection. We specifically identified in vivo transfer of the plasmid to resident Klebsiella pneumoniae in the mouse gut. Our findings highlight the potential for environmental bacteria exposed to antibiotics to transmit resistance genes to mammalian pathogens during ingestion of leafy greens. IMPORTANCE Previous efforts have correlated antibiotic-fed livestock and meat products with respective antibiotic resistance genes, but virtually no research has been conducted on the transmission of antibiotic resistance from plant foods to the mammalian gut (C. S. Hölzel, J. L. Tetens, and K. Schwaiger, Pathog Dis 15:671–688, 2018, https://doi.org/10.1089/fpd.2018.2501; C. M. Liu et al., mBio 9:e00470-19, 2018, https://doi.org/10.1128/mBio.00470-18; B. Spellberg et al., NAM Perspectives, 2016, https://doi.org/10.31478/201606d; J. O’Neill, Antimicrobials in agriculture and the environment, 2015; Centers for Disease Control and Prevention, Antibiotic resistance threats in the United States, 2019). Here, we sought to determine if horizontal transmission of antibiotic resistance genes can occur between lettuce and the mammalian gut microbiome, using a mouse model. Furthermore, we have created a new model to study horizontal gene transfer on lettuce leaves using an antibiotic-resistant transformant of A. baylyi (AbzeoR).

scholarly journals Selection for Reducing Energy Cost of Protein Production Drives the GC Content and Amino Acid Composition Bias in Gene Transfer Agents

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Roman Kogay ◽  
Yuri I. Wolf ◽  
Eugene V. Koonin ◽  
Olga Zhaxybayeva
Keyword(s):  
Amino Acid ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Nutrient Availability ◽  
Energy Cost ◽  
Group Selection ◽  
Protein Production ◽  
Bacterial Populations ◽  
Selection For ◽  
Transfer Agents

ABSTRACT Gene transfer agents (GTAs) are virus-like elements integrated into bacterial genomes, particularly, those of Alphaproteobacteria. The GTAs can be induced under conditions of nutritional stress, incorporate random fragments of bacterial DNA into miniphage particles, lyse the host cells, and infect neighboring bacteria, thus enhancing horizontal gene transfer. We show that GTA genes evolve under conditions of pronounced positive selection for the reduction of the energy cost of protein production as shown by comparison of the amino acid compositions with those of both homologous viral genes and host genes. The energy saving in GTA genes is comparable to or even more pronounced than that in the genes encoding the most abundant, essential bacterial proteins. In cases in which viruses acquire genes from GTAs, the bias in amino acid composition disappears in the course of evolution, showing that reduction of the energy cost of protein production is an important factor of evolution of GTAs but not bacterial viruses. These findings strongly suggest that GTAs represent bacterial adaptations rather than selfish, virus-like elements. Because GTA production kills the host cell and does not propagate the GTA genome, it appears likely that the GTAs are retained in the course of evolution via kin or group selection. Therefore, we hypothesize that GTAs facilitate the survival of bacterial populations under energy-limiting conditions through the spread of metabolic and transport capabilities via horizontal gene transfer and increases in nutrient availability resulting from the altruistic suicide of GTA-producing cells. IMPORTANCE Kin selection and group selection remain controversial topics in evolutionary biology. We argue that these types of selection are likely to operate in bacterial populations by showing that bacterial gene transfer agents (GTAs), but not related viruses, evolve under conditions of positive selection for the reduction of the energy cost of GTA particle production. We hypothesize that GTAs are dedicated devices mediating the survival of bacteria under conditions of nutrient limitation. The benefits conferred by GTAs under nutritional stress conditions appear to include horizontal dissemination of genes that could provide bacteria with enhanced capabilities for nutrient utilization and increases of nutrient availability occurring through the lysis of GTA-producing bacteria.

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