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

2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Shasha Wang ◽  
Weizhi He ◽  
Wenxia Sun ◽  
Jun Zhang ◽  
Yaowen Chang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Antibiotic Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Dna Recombination ◽  
Aminoglycoside Resistance ◽  
Content Type ◽  
Clinical Strains ◽  
Class 1 Integrons ◽  
Class 1

ABSTRACTClass 1 integrons accumulate antibiotic resistance genes by site-specific recombination ataatI-1sites. 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 thePseudomonas fluorescensclass 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 (bothaacandaad) recombinants. For theaacrecombinants, representative sequences showed up to 6-fold aminoglycoside-dependent 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 theP. fluorescensriboswitch 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.

scholarly journals Incidence, Distribution, and Spread of Tetracycline Resistance Determinants and Integron-Associated Antibiotic Resistance Genes among Motile Aeromonads from a Fish Farming Environment

2001 ◽  
Vol 67 (12) ◽  
pp. 5675-5682 ◽  
Author(s):  
Anja S. Schmidt ◽  
Morten S. Bruun ◽  
Inger Dalsgaard ◽  
Jens L. Larsen
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Tetracycline Resistance ◽  
Class 1 Integron ◽  
Gene Cassettes ◽  
Class 1 Integrons ◽  
Resistance Determinants ◽  
Class 1

ABSTRACT A collection of 313 motile aeromonads isolated at Danish rainbow trout farms was analyzed to identify some of the genes involved in high levels of antimicrobial resistance found in a previous field trial (A. S. Schmidt, M. S. Bruun, I. Dalsgaard, K. Pedersen, and J. L. Larsen, Appl. Environ. Microbiol. 66:4908–4915, 2000), the predominant resistance phenotype (37%) being a combined oxytetracycline (OTC) and sulphadiazine/trimethoprim resistance. Combined sulphonamide/trimethoprim resistance (135 isolates) appeared closely related to the presence of a class 1 integron (141 strains). Among the isolates containing integrons, four different combinations of integrated resistance gene cassettes occurred, in all cases including a dihydrofolate reductase gene and a downstream aminoglycoside resistance insert (87 isolates) and occasionally an additional chloramphenicol resistance gene cassette (31 isolates). In addition, 23 isolates had “empty” integrons without inserted gene cassettes. As far as OTC resistance was concerned, only 66 (30%) out of 216 resistant aeromonads could be assigned to resistance determinant class A (19 isolates), D (n = 6), or E (n = 39); three isolates contained two tetracycline resistance determinants (AD, AE, and DE). Forty OTC-resistant isolates containing large plasmids were selected as donors in a conjugation assay, 27 of which also contained a class 1 integron. Out of 17 successful R-plasmid transfers to Escherichia coli recipients, the respective integrons were cotransferred along with the tetracycline resistance determinants in 15 matings. Transconjugants were predominantly tetApositive (10 of 17) and contained class 1 integrons with two or more inserted antibiotic resistance genes. While there appeared to be a positive correlation between conjugative R-plasmids andtetA among the OTC-resistant aeromonads, tetEand the unclassified OTC resistance genes as well as class 1 integrons were equally distributed among isolates with and without plasmids. These findings indicate the implication of other mechanisms of gene transfer besides plasmid transfer in the dissemination of antibiotic resistance among environmental motile aeromonads.

scholarly journals Resistance Genes and Genetic Elements Associated with Antibiotic Resistance in Clinical and Commensal Isolates of Streptococcus salivarius

2015 ◽  
Vol 81 (12) ◽  
pp. 4155-4163 ◽  
Author(s):  
Fanny Chaffanel ◽  
Florence Charron-Bourgoin ◽  
Virginie Libante ◽  
Nathalie Leblond-Bourget ◽  
Sophie Payot
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Genetic Linkage ◽  
Antibiotic Resistance Genes ◽  
Tetracycline Resistance ◽  
Streptococcus Salivarius ◽  
Content Type ◽  
Clinical Strains ◽  
Genetic Elements

ABSTRACTThe diversity of clinical (n= 92) and oral and digestive commensal (n= 120) isolates ofStreptococcus salivariuswas analyzed by multilocus sequence typing (MLST). No clustering of clinical or commensal strains can be observed in the phylogenetic tree. Selected strains (92 clinical and 46 commensal strains) were then examined for their susceptibilities to tetracyclines, macrolides, lincosamides, aminoglycosides, and phenicol antibiotics. The presence of resistance genestet(M),tet(O),erm(A),erm(B),mef(A/E), andcatQand associated genetic elements was investigated by PCR, as was the genetic linkage of resistance genes. High rates of erythromycin and tetracycline resistance were observed among the strains. Clinical strains displayed either theerm(B) (macrolide-lincosamide-streptogramin B [MLSB] phenotype) ormef(A/E) (M phenotype) resistance determinant, whereas almost all the commensal strains harbored themef(A/E) resistance gene, carried by a macrolide efflux genetic assembly (MEGA) element. A genetic linkage between a macrolide resistance gene and genes of Tn916was detected in 23 clinical strains and 5 commensal strains, with a predominance of Tn3872elements (n= 13), followed by Tn6002(n= 11) and Tn2009(n= 4) elements. Four strains harboring amef(A/E) gene were also resistant to chloramphenicol and carried acatQgene. Sequencing of the genome of one of these strains revealed that these genes colocalized on an IQ-like element, as already described for other viridans group streptococci. ICESt3-related elements were also detected in half of the isolates. This work highlights the potential role ofS. salivariusin the spread of antibiotic resistance genes both in the oral sphere and in the gut.

scholarly journals Distribution and Content of Class 1 Integrons in Different Vibrio cholerae O-Serotype Strains Isolated in Thailand

2000 ◽  
Vol 44 (5) ◽  
pp. 1315-1321 ◽  
Author(s):  
Anders Dalsgaard ◽  
Anita Forslund ◽  
Oralak Serichantalergs ◽  
Dorthe Sandvang
Keyword(s):  
Antibiotic Resistance ◽  
Vibrio Cholerae ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antibiotic Resistance Gene ◽  
Antibiotic Resistance Genes ◽  
Gene Cassette ◽  
Gene Cassettes ◽  
Class 1 Integrons ◽  
Class 1

ABSTRACT In this study, 176 clinical and environmental Vibrio cholerae strains of different O serotypes isolated in Thailand from 1982 to 1995 were selected and studied for the presence of class 1 integrons, a new group of genetic elements which carry antibiotic resistance genes. Using PCR and DNA sequencing, we found that 44 isolates contained class 1 integrons harboring the aadB,aadA2, blaP1, dfrA1, anddfrA15 gene cassettes, which encode resistance to gentamicin, kanamycin, and tobramycin; streptomycin and spectinomycin; β-lactams; and trimethoprim, respectively. Each cassette array contained only a single antibiotic resistance gene. Although resistance genes in class 1 integrons were found in strains from the same epidemic, as well as in unrelated non-O1, non-O139 strains isolated from children with diarrhea, they were found to encode only some of the antibiotic resistance expressed by the strains. Serotype O139 strains did not contain class 1 integrons. However, the appearance and disappearance of the O139 serotype in the coastal city Samutsakorn in 1992 and 1993 were associated with the emergence of a distinct V. cholerae O1 strain which contained the aadA2resistance gene cassette. A 150-kb self-transmissible plasmid found in three O1 strains isolated in 1982 contained the aadB gene cassette. Surprisingly, several strains harbored two integrons containing different cassettes. Thus, class 1 integrons containing various resistance gene cassettes are distributed among differentV. cholerae O serotypes of mainly clinical origin in Thailand.

scholarly journals Distribution of Medically Relevant Antibiotic Resistance Genes and Mobile Genetic Elements in Soils of Temperate Forests and Grasslands Varying in Land Use

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 150 ◽  
Author(s):  
Inka M. Willms ◽  
Jingyue Yuan ◽  
Caterina Penone ◽  
Kezia Goldmann ◽  
Juliane Vogt ◽  
...  
Keyword(s):  
Land Use ◽  
Antibiotic Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Forest Soils ◽  
Antibiotic Resistance Genes ◽  
Mobile Genetic Elements ◽  
Class 1 Integrons ◽  
Genetic Elements ◽  
Class 1

Antibiotic-resistant pathogens claim the lives of thousands of people each year and are currently considered as one of the most serious threats to public health. Apart from clinical environments, soil ecosystems also represent a major source of antibiotic resistance determinants, which can potentially disseminate across distinct microbial habitats and be acquired by human pathogens via horizontal gene transfer. Therefore, it is of global importance to retrieve comprehensive information on environmental factors, contributing to an accumulation of antibiotic resistance genes and mobile genetic elements in these ecosystems. Here, medically relevant antibiotic resistance genes, class 1 integrons and IncP-1 plasmids were quantified via real time quantitative PCR in soils derived from temperate grasslands and forests, varying in land use over a large spatial scale. The generated dataset allowed an analysis, decoupled from regional influences, and enabled the identification of land use practices and soil characteristics elevating the abundance of antibiotic resistance genes and mobile genetic elements. In grassland soils, the abundance of the macrolide resistance gene mefA as well as the sulfonamide resistance gene sul2 was positively correlated with organic fertilization and the abundance of aac(6′)-lb, conferring resistance to different aminoglycosides, increased with mowing frequency. With respect to forest soils, the beta-lactam resistance gene blaIMP-12 was significantly correlated with fungal diversity which might be due to the fact that different fungal species can produce beta-lactams. Furthermore, except blaIMP-5 and blaIMP-12, the analyzed antibiotic resistance genes as well as IncP-1 plasmids and class-1 integrons were detected less frequently in forest soils than in soils derived from grassland that are commonly in closer proximity to human activities.

scholarly journals Molecular Basis of Sulfonamide and Trimethoprim Resistance in Fish-Pathogenic Aeromonas Isolates

2011 ◽  
Vol 77 (20) ◽  
pp. 7147-7150 ◽  
Author(s):  
Kristina Kadlec ◽  
Ellen von Czapiewski ◽  
Heike Kaspar ◽  
Jürgen Wallmann ◽  
Geovana Brenner Michael ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Molecular Basis ◽  
Aeromonas Salmonicida ◽  
The Novel ◽  
Content Type ◽  
Gene Cassettes ◽  
Class 1 Integrons ◽  
Novel Gene ◽  
Class 1 ◽  
Diseased Fish

ABSTRACTSulfonamide-trimethoprim-resistantAeromonas salmonicidaand motileAeromonasspp. from diseased fish of the GERM-Vet study carried thesul1gene together with mostly cassette-borne trimethoprim resistance genes, including the novel genedfrA28. The sevendfrAanddfrBgenes identified were located mostly in class 1 integrons which commonly harbored other gene cassettes.

scholarly journals Increased Resistance to Multiple Antimicrobials and Altered Resistance Gene Expression in CMY-2-Positive Salmonella enterica following a Simulated Patient Treatment with Ceftriaxone

2012 ◽  
Vol 78 (22) ◽  
pp. 8062-8066 ◽  
Author(s):  
Russell D. Hamilton ◽  
Holly J. Hulsebus ◽  
Samina Akbar ◽  
Jeffrey T. Gray
Keyword(s):  
Gene Expression ◽  
Antimicrobial Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Salmonella Enterica ◽  
The United States ◽  
Simulated Patient ◽  
Patient Treatment ◽  
Content Type

ABSTRACTSalmonellosis is one of the most common causes of food-borne disease in the United States. Increasing antimicrobial resistance and corresponding increases in virulence present serious challenges. Currently, empirical therapy for invasiveSalmonella entericainfection includes either ceftriaxone or ciprofloxacin (E. L. Hohmann, Clin. Infect. Dis. 32:263–269, 2001). TheblaCMY-2gene confers resistance to ceftriaxone, the antimicrobial of choice for pediatric patients with invasiveSalmonella entericainfections, making these infections especially dangerous (J. M. Whichard et al., Emerg. Infect. Dis. 11:1464–1466, 2005). We hypothesized thatblaCMY-2-positiveSalmonella entericawould exhibit increased MICs to multiple antimicrobial agents and increased resistance gene expression following exposure to ceftriaxone using a protocol that simulated a patient treatmentin vitro. SevenSalmonella entericastrains survived a simulated patient treatmentin vitroand, following treatment, exhibited a significantly increased ceftriaxone MIC. Not only would these isolates be less responsive to further ceftriaxone treatment, but because theblaCMY-2genes are commonly located on large, multidrug-resistant plasmids, increased expression of theblaCMY-2gene may be associated with increased expression of other drug resistance genes located on the plasmid (N. D. Hanson and C. C. Sanders, Curr. Pharm. Des. 5:881–894, 1999). The results of this study demonstrate that a simulated patient treatment with ceftriaxone can alter the expression of antimicrobial resistance genes, includingblaCMY-2andfloRinS. entericaserovar Typhimurium andS. entericaserovar Newport. Additionally, we have shown increased MICs following a simulated patient treatment with ceftriaxone for tetracycline, amikacin, ceftriaxone, and cefepime, all of which have resistance genes commonly located on CMY-2 plasmids. The increases in resistance observed are significant and may have a negative impact on both public health and antimicrobial resistance ofSalmonella enterica.

scholarly journals The Evolution of Class 1 Integrons and the Rise of Antibiotic Resistance

2008 ◽  
Vol 190 (14) ◽  
pp. 5095-5100 ◽  
Author(s):  
Michael Gillings ◽  
Yan Boucher ◽  
Maurizio Labbate ◽  
Andrew Holmes ◽  
Samyuktha Krishnan ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Lateral Transfer ◽  
Natural Environments ◽  
Class 1 Integrons ◽  
Wide Range ◽  
Human Food Chain ◽  
Class 1 ◽  
Phylogenetic Signature

ABSTRACT Class 1 integrons are central players in the worldwide problem of antibiotic resistance, because they can capture and express diverse resistance genes. In addition, they are often embedded in promiscuous plasmids and transposons, facilitating their lateral transfer into a wide range of pathogens. Understanding the origin of these elements is important for the practical control of antibiotic resistance and for exploring how lateral gene transfer can seriously impact on, and be impacted by, human activities. We now show that class 1 integrons can be found on the chromosomes of nonpathogenic soil and freshwater Betaproteobacteria. Here they exhibit structural and sequence diversity, an absence of antibiotic resistance genes, and a phylogenetic signature of lateral transfer. Some examples are almost identical to the core of the class 1 integrons now found in pathogens, leading us to conclude that environmental Betaproteobacteria were the original source of these genetic elements. Because these elements appear to be readily mobilized, their lateral transfer into human commensals and pathogens was inevitable, especially given that Betaproteobacteria carrying class 1 integrons are common in natural environments that intersect with the human food chain. The strong selection pressure imposed by the human use of antimicrobial compounds then ensured their fixation and global spread into new species.

scholarly journals Analysis of Class 1 Integrons and Antibiotic Resistance Genes in Pseudomonas aeruginosa Strains from Benin City, Nigeria

2020 ◽  
Vol 24 (4) ◽  
pp. 633-637
Author(s):  
B.O. Isichei-Ukah ◽  
O.I. Enabulele
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Environmental Isolates ◽  
Significance Level ◽  
Beta Lactamases ◽  
Class 1 Integrons ◽  
Benin City ◽  
Class 1

The presence of integrons and antibiotic resistance genes in the genome of Pseudomonas aeruginosa pose a serious problem in the treatment and control of infections caused by this pathogen in hospitals. This study was carried to analyse the presence of class 1 integrons and some antibiotic resistance genes on selected clinical and environmental strains of Pseudomonas aeruginosa. A total of 120 strains were employed for this study.The strains were confirmed using molecular method and species-specific primers targeting the 16S ribosomal ribonucleic acid (rRNA). Polymerase chain reaction (PCR) was used to detect the presence of class 1 integrons and resistance genes using appropriate primers and conditions. The strains were analysed for the presence of the following antibiotic resistance genes - aadA, blaPSE, blaAMPC, blaIMP and tetC encoding  aminoglycosides, betalactamases, metallo-beta-lactamases (MBL) and tetracylines resistance respectively. On screening the isolates for the presence of class 1 integrons, 50/60 (83.3 %) clinical isolates and 46/60 (76.7 %) environmental isolates showed positive results (P > 0.05). In both clinical and environmental isolates, the highest occurring resistance genes were blaAMPC and tetC (encoding beta-lactamases and tetracylines respectively), while the least was observed in blaIMP (encoding metallo-beta-lactamases). In comparison, there was high significance difference (at P<0.01 significance level) in the resistance gene blaPSE between the clinical and environmental strains. The high prevalence of these resistance genes is a great threat in the treatment of Pseudomonas infections. Keywords: Pseudomonas aeruginosa, Resistance genes, Integrons, Beta-lactamases.

scholarly journals Colocation of the Multiresistance Gene cfr and the Fosfomycin Resistance Gene fosD on a Novel Plasmid in Staphylococcus arlettae from a Chicken Farm

2017 ◽  
Vol 61 (12) ◽  
Author(s):  
Bi-Hui Liu ◽  
Chang-Wei Lei ◽  
An-Yun Zhang ◽  
Yun Pan ◽  
Ling-Han Kong ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
The Novel ◽  
Content Type ◽  
Chicken Farm ◽  
Fosfomycin Resistance ◽  
First Time

ABSTRACT The novel 63,558-bp plasmid pSA-01, which harbors nine antibiotic resistance genes, including cfr, erm(C), tet(L), erm(T), aadD, fosD, fexB, aacA-aphD, and erm(B), was characterized in Staphylococcus arlettae strain SA-01, isolated from a chicken farm in China. The colocation of cfr and fosD genes was detected for the first time in an S. arlettae plasmid. The detection of two IS431-mediated circular forms containing resistance genes in SA-01 suggested that IS431 may facilitate dissemination of antibiotic resistance genes.

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