The role of chemotaxis and efflux pumps on nitrate reduction in the toxic regions of a ciprofloxacin concentration gradient

Alcalde, Reinaldo E.; Dundas, Christopher M.; Dong, Yiran; Sanford, Robert A.; Keitz, Benjamin K.; Fouke, Bruce W.; Werth, Charles J.

doi:10.1038/s41396-021-00975-1

“…These results suggest that we are observing a direct response to the antibiotics. There is a growing body of work showing that flagella-based swimming can transport bacteria into regions of high antibiotic concentration 37 – 40 . However, to the best of our knowledge, there is no evidence of chemotaxis in response to the antibiotic gradients themselves.…”

Section: Resultsmentioning

confidence: 99%

Suicidal chemotaxis in bacteria

Oliveira

¹

,

Wheeler

²

,

Deroy

³

et al. 2022

View full text Add to dashboard Cite

Bacteria commonly live in surface-associated communities where steep gradients of antibiotics and other chemical compounds can occur. While many bacterial species move on surfaces, we know surprisingly little about how such antibiotic gradients affect cell motility. Here, we study the behaviour of the opportunistic pathogen Pseudomonas aeruginosa in stable spatial gradients of several antibiotics by tracking thousands of cells in microfluidic devices as they form biofilms. Unexpectedly, these experiments reveal that bacteria use pili-based (‘twitching’) motility to navigate towards antibiotics. Our analyses suggest that this behaviour is driven by a general response to the effects of antibiotics on cells. Migrating bacteria reach antibiotic concentrations hundreds of times higher than their minimum inhibitory concentration within hours and remain highly motile. However, isolating cells - using fluid-walled microfluidic devices - reveals that these bacteria are terminal and unable to reproduce. Despite moving towards their death, migrating cells are capable of entering a suicidal program to release bacteriocins that kill other bacteria. This behaviour suggests that the cells are responding to antibiotics as if they come from a competing colony growing nearby, inducing them to invade and attack. As a result, clinical antibiotics have the potential to lure bacteria to their death.

show abstract

“…Depletion of chemotaxis-related genes has been shown to affect the antimicrobial susceptibilities of Aeromonas hydrophila [ 84 ]. Chemotaxis not only facilitates the ability of Shewanella oneidensis MR-1 to colonize but also maintains metabolic activity in regions where the antibiotic ciprofloxacin exhibits high toxicity [ 85 ]. The chemotaxis histidine kinase CheA has the ability to phosphorylate not only its specific response regulator CheY2, but also one of the response regulators involved in the pathway that mediates biofilm formation, FlmD [ 86 ].…”

Section: Resultsmentioning

confidence: 99%

Acquisition of Type I methyltransferase via horizontal gene transfer increases the drug resistance of Aeromonas veronii

Ma,

Zhao,

Mo

et al. 2023

View full text Add to dashboard Cite

Aeromonas veronii is an opportunistic pathogen that affects both fish and mammals, including humans, leading to bacteraemia, sepsis, meningitis and even death. The increasing virulence and drug resistance of A. veronii are of significant concern and pose a severe risk to public safety. The Type I restriction-modification (RM) system, which functions as a bacterial defence mechanism, can influence gene expression through DNA methylation. However, little research has been conducted to explore its origin, evolutionary path, and relationship to virulence and drug resistance in A. veronii . In this study, we analysed the pan-genome of 233 A . veronii strains, and the results indicated that it was 'open', meaning that A. veronii has acquired additional genes from other species. This suggested that A. veronii had the potential to adapt and evolve rapidly, which might have contributed to its drug resistance. One Type I methyltransferase (MTase) and two complete Type I RM systems were identified, namely AveC4I, AveC4II and AveC4III in A. veronii strain C4, respectively. Notably, AveC4I was exclusive to A. veronii C4. Phylogenetic analysis revealed that AveC4I was derived from horizontal gene transfer from Thiocystis violascens and exchanged genes with the human pathogen Comamonas kerstersii . Single molecule real-time sequencing was applied to identify the motif methylated by AveC4I, which was unique and not recognized by any reported MTases in the REBASE database. We also annotated the functions and pathways of the genes containing the motif, revealing that AveC4I may control drug resistance in A. veronii C4. Our findings provide new insight on the mechanisms underlying drug resistance in pathogenic bacteria. By identifying the specific genes and pathways affected by AveC4I, this study may aid in the development of new therapeutic approaches to combat A. veronii infections.

show abstract

“…RND efflux pumps are bacterial drug-resistance mechanisms that efflux a variety of hazardous substances to the outside of the cell, and there are five types of efflux pumps in E. coli [ 33 , 34 , 35 , 36 , 37 ]. It has previously been reported in the literature that the RND exocytosis pump plays a key role in the organic solvent tolerance and multidrug resistance of bacteria [ 38 , 39 ]. A previous study on PAH stress in Pseudomonas aeruginosa has shown that bacterial efflux pumps and transport genes play a key role in bacterial resistance to organic solvent toxicity [ 40 ].…”

Section: Discussionmentioning

confidence: 99%

The Effects and Toxicity of Different Pyrene Concentrations on Escherichia coli Using Transcriptomic Analysis

Zhu,

Gong,

Wang

et al. 2024

Microorganisms

0

View full text Add to dashboard Cite

Pyrene is a pollutant in the environment and affects the health of living organisms. It is important to understand microbial-mediated pyrene resistance and the related molecular mechanisms due to its toxicity and biodegradability. Due to the unclear response mechanisms of bacteria to PAHs, this study detected the transcriptional changes in Escherichia coli under different pyrene concentrations using transcriptome sequencing technology. Global transcriptome analysis showed that the number of differentially expressed genes (DEGs) in multiple metabolic pathways increased with increasing concentrations of pyrene. In addition, the effects and toxicity of pyrene on Escherichia coli mainly included the up-regulation and inhibition of genes related to carbohydrate metabolism, membrane transport, sulfate reduction, various oxidoreductases, and multidrug efflux pumps. Moreover, we also constructed an association network between significantly differentially expressed sRNAs and key genes and determined the regulatory relationship and key genes of Escherichia coli under pyrene stress. Our study utilized pyrene as an exogenous stress substance to investigate the possible pathways of the bacterial stress response. In addition, this study provides a reference for other related research and serves as a foundation for future research.

show abstract

The role of chemotaxis and efflux pumps on nitrate reduction in the toxic regions of a ciprofloxacin concentration gradient

Cited by 8 publications

References 68 publications

Suicidal chemotaxis in bacteria

Suicidal chemotaxis in bacteria

Acquisition of Type I methyltransferase via horizontal gene transfer increases the drug resistance of Aeromonas veronii

The Effects and Toxicity of Different Pyrene Concentrations on Escherichia coli Using Transcriptomic Analysis

Contact Info

Product

Resources

About