Conjugal transfer of aac(6′)Ie-aph(2″)Ia gene from native species and mechanism of regulation and cross resistance in Enterococcus faecalis MCC3063 by real time-PCR

Jaimee, George; Halami, Prakash M.

doi:10.1016/j.micpath.2017.07.049

Cited by 9 publications

(3 citation statements)

References 42 publications

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“…Nevertheless, in spite of its frequent presence in enterococci 45 there is no evidence of its former plasmid-associated appearance in L. plantarum . We found that gene aph(3’)-IIIa of T. halophilus was encoded on a plasmid that is consistent with the fact that aph(3’)IIIa is often identified on high molecular weight plasmids and chromosomes of the enterococcal species 46 . Nonetheless, to the best of our knowledge, a description of the aph(3’)-IIIa gene in T. halophilus is a pioneer finding.…”

Section: Discussionsupporting

confidence: 84%

Antimicrobial resistance determinants in silage

Nagy

Tóth

Papp

et al. 2022

Sci Rep

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Animal products may play a role in developing and spreading antimicrobial resistance in several ways. On the one hand, residues of antibiotics not adequately used in animal farming can enter the human body via food. However, resistant bacteria may also be present in animal products, which can transfer the antimicrobial resistance genes (ARG) to the bacteria in the consumer’s body by horizontal gene transfer. As previous studies have shown that fermented foods have a meaningful ARG content, it is indicated that such genes may also be present in silage used as mass feed in the cattle sector. In our study, we aspired to answer what ARGs occur in silage and what mobility characteristics they have? For this purpose, we have analyzed bioinformatically 52 freely available deep sequenced silage samples from shotgun metagenome next-generation sequencing. A total of 16 perfect matched ARGs occurred 54 times in the samples. More than half of these ARGs are mobile because they can be linked to integrative mobile genetic elements, prophages or plasmids. Our results point to a neglected but substantial ARG source in the food chain.

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Section: Discussionsupporting

confidence: 84%

Antimicrobial resistance determinants in silage

Nagy

Tóth

Papp

et al. 2022

Sci Rep

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“…The aminoglycosides are exemplary Michaelis-Menten substrates for the acetyltransferase enzymes (50,51). Thus, although basal levels of gene expression are associated with the aac riboswitch sequences, because the catalytic rate of the enzyme is proportional to enzyme concentration, even a small increase in enzyme concentration will lead to a proportional increase in substrate turnover (we observed 2-to 5-fold induction, comparable to that observed in clinical strains [42]), such that at much higher enzyme concentrations, it is likely that the acetyl cofactor (acetyl coenzyme A) would become limiting; thus, no benefit from the production of an additional acetyltransferase enzyme would accrue. The riboswitch may therefore be regarded as a "dimmer switch" (52) that provides a response proportional to the dose of the drug.…”

Section: Discussionsupporting

confidence: 63%

Integron-Derived Aminoglycoside-Sensing Riboswitches Control Aminoglycoside Acetyltransferase Resistance Gene Expression

Wang

Sun

et al. 2019

Antimicrob Agents Chemother

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Class 1 integrons accumulate antibiotic resistance genes by site-specific recombination at aatI-1 sites. Captured genes are transcribed from a promoter located within the integron; for class 1 integrons, the first gene to be transcribed and translated normally encodes an aminoglycoside antibiotic resistance protein (either an acetyltransferase [AAC] or adenyltransferase [AAD]). The leader RNA from the Pseudomonas fluorescens class 1 integron contains an aminoglycoside-sensing riboswitch RNA that controls the expression of the downstream aminoglycoside resistance gene. Here, we explore the relationship between integron-dependent DNA recombination and potential aminoglycoside-sensing riboswitch products of recombination derived from a series of aminoglycoside-resistant clinical strains. Sequence analysis of the clinical strains identified a series of sequence variants that were associated with class I integron-derived aminoglycoside-resistant (both aac and aad) recombinants. For the aac recombinants, representative sequences showed up to 6-fold aminoglycosidedependent regulation of reporter gene expression. Microscale thermophoresis (MST) confirmed RNA binding. Covariance analysis generated a secondary-structure model for the RNA that is an independent verification of previous models that were derived from mutagenesis and chemical probing data and that was similar to that of the P. fluorescens riboswitch RNA. The aminoglycosides were among the first antibiotics to be used clinically, and the data suggest that in an aminoglycoside-rich environment, functional riboswitch recombinants were selected during integron-mediated recombination to regulate aminoglycoside resistance. The incorporation of a functional aminoglycoside-sensing riboswitch by integron recombination confers a selective advantage for the expression of resistance genes of diverse origins.

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“…For the aac riboswitch RNA, each RNA sequence showed distinctive discrimination between different aminoglycosides in the reporter assay. For instance, among the aminoglycosides gentamicin-induced the highest levels of reporter gene expression for the aac -6 RNA, but sisomicin gave the highest reporter gene expression for aac -4 RNA and the optimal fold changes (~2-5 fold induction) were comparable to those observed in a clinical setting [ 36 , 49 ]. Here, in contrast to the aac riboswitch RNA, amikacin induces optimal reporter gene expression for each of the aad riboswitch RNAs that were investigated.…”

Section: Discussionmentioning

confidence: 99%

Aminoglycoside riboswitch control of the expression of integron associated aminoglycoside resistance adenyltransferases

et al. 2020

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The proliferation of antibiotic resistance has its origins in horizontal gene transfer. The class 1 integrons mediate gene transfer by assimilating antibiotic-resistance genes through site-specific recombination. For the class 1 integrons the first assimilated gene normally encodes an aminoglycoside antibiotic resistance protein which is either an aminoglycoside acetyltransferase (AAC), nucleotidyltransferase – (ANT), or adenyl transferase (AAD). An aminoglycoside-sensing riboswitch RNA in the leader RNA of AAC/AAD that controls the expression of aminoglycoside resistance genes has been previously described. Here we explore the relationship between the recombinant products of integron recombination and a series of candidate riboswitch RNAs in the 5ʹ UTR of aad (aminoglycoside adenyltransferases) genes. The RNA sequences from the 5ʹ UTR of the aad genes from pathogenic strains that are the products of site-specific DNA recombination by class 1 integrons were investigated. Reporter assays, MicroScale Thermophoresis (MST) and covariance analysis revealed that a functional aminoglycoside-sensing riboswitch was selected at the DNA level through integron-mediated site-specific recombination. This study explains the close association between integron recombination and the aminoglycoside-sensing riboswitch RNA.

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Conjugal transfer of aac(6′)Ie-aph(2″)Ia gene from native species and mechanism of regulation and cross resistance in Enterococcus faecalis MCC3063 by real time-PCR

Cited by 9 publications

References 42 publications

Antimicrobial resistance determinants in silage

Antimicrobial resistance determinants in silage

Integron-Derived Aminoglycoside-Sensing Riboswitches Control Aminoglycoside Acetyltransferase Resistance Gene Expression

Aminoglycoside riboswitch control of the expression of integron associated aminoglycoside resistance adenyltransferases

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