Integrons in the Intestinal Microbiota as Reservoirs for Transmission of Antibiotic Resistance Genes

Ray, Anuradha; Avershina, Ekaterina; Ludvigsen, Jane; L’Abée-Lund, Trine M.; Rudi, Knut

doi:10.3390/pathogens3020238

Cited by 53 publications

(46 citation statements)

References 68 publications

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“…Within integrons in both TMP/SMX- and GENT-resistant strains, all isolates within a given fecal sample contained the same ARG. This further supports the claim that genes are readily horizontally transferred to one another within the human gut, with integrons playing a particularly important role in this process (20). Gene cassettes present in the commensal bacteria analyzed in this study possessed sequences that were annotated to belong to carbapenemase and metallo-carbapenemase genes ( bla KPC , bla NDM , bla IMP , bla VIM ) as well as mcr -variant genes (Table 2).…”

Section: Discussionsupporting

confidence: 81%

“…ARG mobile elements include integrons, transposons, and plasmids. Integrons, which permit the simultaneous integration of multiple exogenous gene cassettes, represent an important vehicle for the rapid horizontal transfer of resistance across bacterial populations and thus could contribute to the sudden increase in prevalence of multidrug-resistant infections in a community (19, 20). In particular, class 1 integrons are the most ubiquitous class of integrons in enteric bacteria and have been found in all common pathogens including Escherichia , Klebsiella , Salmonella , Shigella , and other disease-causing Enterobacteriaceae.…”

Section: Introductionmentioning

confidence: 99%

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Prevalence of antimicrobial resistance genes and integrons in commensal Gram-negative bacteria in a college community

Rubin¹,

Mussio²,

et al. 2019

Preprint

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Although the human intestinal microbiome has been shown to harbor antimicrobial drug-resistance genes (ARG), the prevalence of such genes in a healthy population and their impact on extraintestinal infections that occur in that community are not well established. This study sought to identify ARG prevalence and their mobile elements in the intestines of a healthy community population at a California university, and compared these genes to those found in uropathogenic Escherichia coli isolated from patients with community-acquired urinary tract infection (CA-UTI). We isolated Gram-negative bacteria (GNB) from fecal samples of healthy volunteers and screened them by polymerase chain reaction (PCR) for ARG encoding resistance against ampicillin (AMP), trimethoprim-sulfamethoxazole (TMP-SMX), gentamicin (GENT), and colistin (COL). We found antimicrobial resistant GNB from 85 (83%) of 102 non-redundant rectal swab samples. Sixty-seven (66%) of these samples contained ß-lactamase genes (blaTEM, blaSHV, blaCTX-M, blaOXA,blaOXY), dihydrofolate reductase (DHFR) genes (dhfr-A17, dhfr-A7, dhfr-A5, dhfr-A21, dhfr-A1, dhfr-A15, and dhfr-B3), and aminoglycoside resistance genes (aadA5, aadA1, and aadB). Integron sequences were found in 37 fecal samples. These genes were found in 11 different GNB species isolated from the fecal samples. The same ARG were found in E. coli strains isolated from patients with CA-UTI examined at the college outpatient health clinic. The high prevalence of clinically-common ARG and integrons harbored by GNB in the intestine of a healthy population suggest that human intestines may serve as a major reservoir of these mobile ARG that appear in E. coli strains causing extraintestinal infections in the same community.ImportanceIncreasing frequency of antimicrobial resistance (AMR) in human pathogenic bacteria has compromised our ability to treat infections. Since mobile antibiotic resistance genes (ARG) are readily exchanged between different species of bacteria through horizontal gene transfer, there is interest in investigating sources of these genes. The normal intestinal flora has been shown to contain a wide variety of ARG, which may have been introduced via food-containing AMR bacteria. We sought to assess the prevalence of ARG carriage in the intestines of a healthy population and determine if these ARG are found in E. coli strains that cause community-acquired urinary tract infection (CA-UTI) in the same community. Our findings indicate that the human intestine may serve as an important reservoir as well as a site in which ARG are transferred into E. coli that cause UTI. Further research is needed to reduce ARG carriage and devise new strategies to prevent AMR infections.

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Section: Discussionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Prevalence of antimicrobial resistance genes and integrons in commensal Gram-negative bacteria in a college community

Rubin¹,

Mussio²,

et al. 2019

Preprint

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“…Integrons are genetically non-mobile elements, involved in the integration of gene cassettes and responsible for the transmission of e.g. ARGs (Ravi et al, 2014). A positive correlation between the abundance of the class I integrons and the concentrations of Cu, Zn, Hg, and Pb has been shown in freshwater sediment samples (Rosewarne et al, 2010) and the frequency of class I integrons has been postulated as a good proxy for anthropogenic pollution in the environment (Gillings et al, 2015).…”

Section: Co-selection Of Antibiotic and Heavy Metal Resistancementioning

confidence: 99%

Co-selection of antibiotic and heavy metal resistance in freshwater bacteria

2016

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“…This is consistent with previous observations suggesting that the mobilome can evolve independently of the overall composition of the gut microbiota (3). Furthermore, we detected resistance associations for antibiotics other than those used, indicating potential antibiotic resistance linkage (21). Thus, antibiotic usage during labor could be a major contributing factor to antibiotic resistance spread within the infants’ commensal gut microbiota.…”

Section: Discussionmentioning

confidence: 95%

Genetic diversity and mother-child overlap of the gut associated microbiota determined by reduced genome sequencing

Ray¹,

Avershina²,

Il³

et al. 2017

Preprint

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The genetic diversity and sharing of the mother-child associated microbiota remain largely unexplored. This severely limits our functional understanding of gut microbiota transmission patterns. The aim of our work was therefore to use a novel reduced metagenome sequencing in combination with shotgun and 16S rRNA gene sequencing to determine both the metagenome genetic diversity and the mother-to-child sharing of the microbiota. For a cohort of 17 mother-child pairs we found an increase of the collective metagenome size from about 100 Mbp for 4-day-old children to about 500 Mbp for mothers. The 4-day-old children shared 7% of the metagenome sequences with the mothers, while the metagenome sequence sharing was more than 30% among the mothers. We found 15 genomes shared across more than 50% of the mothers, of which 10 belonged to Clostridia. Only Bacteroides showed a direct mother-child association, with B. vulgatus being abundant in both 4-day-old children and mothers. In conclusion, our results support a common pool of gut bacteria that are transmitted from adults to infants, with most of the bacteria being transmitted at a stage after delivery.

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Integrons in the Intestinal Microbiota as Reservoirs for Transmission of Antibiotic Resistance Genes

Cited by 53 publications

References 68 publications

Prevalence of antimicrobial resistance genes and integrons in commensal Gram-negative bacteria in a college community

Prevalence of antimicrobial resistance genes and integrons in commensal Gram-negative bacteria in a college community

Co-selection of antibiotic and heavy metal resistance in freshwater bacteria

Genetic diversity and mother-child overlap of the gut associated microbiota determined by reduced genome sequencing

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