scholarly journals Mosaic Tetracycline Resistance Genes and Their Flanking Regions in Bifidobacterium thermophilum and Lactobacillus johnsonii

2007 ◽  
Vol 52 (1) ◽  
pp. 248-252 ◽  
Author(s):  
Angela H. A. M. van Hoek ◽  
Sigrid Mayrhofer ◽  
Konrad J. Domig ◽  
Ana B. Flórez ◽  
Mohammed S. Ammor ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Efflux Pump ◽  
Hot Spot ◽  
Tetracycline Resistance ◽  
Lactobacillus Johnsonii ◽  
Reading Frame ◽  
Tetracycline Resistance Genes ◽  
Upstream Part ◽  
Bifidobacterium Thermophilum ◽  
Flanking Regions

ABSTRACT For the first time, mosaic tetracycline resistance genes were identified in Lactobacillus johnsonii and in Bifidobacterium thermophilum strains. The L. johnsonii strain investigated contains a complex hybrid gene, tet(O/W/32/O/W/O), whereas the five bifidobacterial strains possess two different mosaic tet genes: i.e., tet(W/32/O) and tet(O/W). As reported by others, the crossover points of the mosaic tet gene segments were found at similar positions within the genes, suggesting a hot spot for recombination. Analysis of the sequences flanking these genes revealed that the upstream part corresponds to the 5′ end of the mosaic open reading frame. In contrast, the downstream region was shown to be more variable. Surprisingly, in one of the B. thermophilum strains a third tet determinant was identified, coding for the efflux pump Tet(L).

Detection of efflux pump genes in multiresistant Acinetobacter baumannii ST2 in Iran

2021 ◽  
Author(s):  
Zahra Meshkat ◽  
Himen Salimizand ◽  
Yousef Amini ◽  
Davood Mansury ◽  
Abolfazl Rafati Zomorodi ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Efflux Pump ◽  
Tetracycline Resistance ◽  
Genomic Diversity ◽  
Expression Level ◽  
Tetracycline Resistance Genes ◽  
Microdilution Method ◽  
Relationship Of ◽  
Repetitive Extragenic Palindromic Pcr

AbstractAcinetobacter baumannii, as a nosocomial pathogen has become a worldwide concern in recent years. In the current study, the resistance to tetracyclines and colistin were assessed in the isolates from different provinces of Iran.During the timeline of this study, a number of 270 isolates of A. baumannii were collected from tracheal aspirates, wounds, urine and blood cultures. The minimum inhibitory concentration (MIC) for tetracycline, doxycycline, minocycline, tigecycline and colistin were evaluated. Tetracycline resistance genes were assessed by PCR. The mean expression level of adeB, adeJ and adeG were assessed using semi quantitative Real-Time PCR. The clonal relationship of the isolates was evaluated by the repetitive extragenic palindromic PCR (REP-PCR), International Clonal (IC) Lineage Multiplex PCR and multilocus sequence typing (MLST) (Pasteur scheme) methods.The MIC by microdilution method showed that 87.5, 51.4, 28, 0.74 and 0% of the isolates were resistant to tetracycline, doxycycline, minocycline, tigecycline and colistin respectively. The prevalence of tetracycline resistance genes was 99.2, 99.2, 98, 86.7, 10, 3.33, 0.37, 0% for adeB, adeJ, adeG, tetB, tetA(39), tetA, tetM and tetH in tetracycline-resistant isolates. Moreover, the expression level of adeB, adeJ, adeG genes in tigecycline-nonsusceptible A. baumannii (TNAB) strain was higher compared to the tigecycline-susceptible A. baumannii (TSAB). A broad genomic diversity was revealed, but ST2 was the most prevalent ST. Our results indicated that tetracycline resistance in Iran is mediated by resistance-nodulation-cell division (RND) and tetB efflux pumps.

scholarly journals Comparative Analysis of Sequences Flanking tet(W) Resistance Genes in Multiple Species of Gut Bacteria

2006 ◽  
Vol 50 (8) ◽  
pp. 2632-2639 ◽  
Author(s):  
Katarzyna A. Kazimierczak ◽  
Harry J. Flint ◽  
Karen P. Scott
Keyword(s):  
Resistance Genes ◽  
Bifidobacterium Longum ◽  
Tetracycline Resistance ◽  
Direct Repeats ◽  
Low Frequencies ◽  
Butyrivibrio Fibrisolvens ◽  
Reading Frame ◽  
Conjugative Transposons ◽  
Tetracycline Resistance Genes ◽  
Multiple Species

ABSTRACT tet(W) is one of the most abundant tetracycline resistance genes found in bacteria from the mammalian gut and was first identified in the rumen anaerobe Butyrivibrio fibrisolvens 1.230, where it is highly mobile and its transfer is associated with the transposable chromosomal element TnB1230. In order to compare the genetic basis for tet(W) carriage in different bacteria, we studied sequences flanking tet(W) in representatives of seven bacterial genera originating in diverse gut environments. The sequences 657 bp upstream and 43 bp downstream of tet(W) were 96 to 100% similar in all strains examined. A common open reading frame (ORF) was identified downstream of tet(W) in five different bacteria, while another conserved ORF that flanked tet(W) in B. fibrisolvens 1.230 was also present upstream of tet(W) in a human colonic Roseburia isolate and in another rumen B. fibrisolvens isolate. In one species, Bifidobacterium longum (strain F8), a novel transposase was located within the conserved 657-bp region upstream of tet(W) and was flanked by imperfect direct repeats. Additional direct repeats 6 bp long were identified on each end of a chromosomal ORF interrupted by the insertion of the putative transposase and the tet(W) gene. This tet(W) gene was transferable at low frequencies between Bifidobacterium strains. A putative minielement carrying a copy of tet(W) was identified in B. fibrisolvens transconjugants that had acquired the tet(W) gene on TnB1230. Several different mechanisms, including mechanisms involving plasmids and conjugative transposons, appear to be involved in the horizontal transfer of tet(W) genes, but small core regions that may function as minielements are conserved.

scholarly journals Novel Insertion Sequence- and Transposon-Mediated Genetic Rearrangements in Genomic Island SGI1 of Salmonella enterica Serovar Kentucky

2008 ◽  
Vol 52 (10) ◽  
pp. 3745-3754 ◽  
Author(s):  
Benoît Doublet ◽  
Karine Praud ◽  
Sophie Bertrand ◽  
Jean-Marc Collard ◽  
François-Xavier Weill ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Salmonella Enterica ◽  
Genomic Island ◽  
Tetracycline Resistance ◽  
Gene Clusters ◽  
Mercury Resistance ◽  
Reading Frame ◽  
Tetracycline Resistance Genes ◽  
Serovar Typhimurium ◽  
Genetic Rearrangements

ABSTRACT Salmonella genomic island 1 (SGI1) is an integrative mobilizable element that harbors a multidrug resistance (MDR) gene cluster. Since its identification in epidemic Salmonella enterica serovar Typhimurium DT104 strains, variant SGI1 MDR gene clusters conferring different MDR phenotypes have been identified in several S. enterica serovars and classified as SGI1-A to -O. A study was undertaken to characterize SGI1 from serovar Kentucky strains isolated from travelers returning from Africa. Several strains tested were found to contain the partially characterized variant SGI1-K, recently described in a serovar Kentucky strain isolated in Australia. This variant contained only one cassette array, aac(3)-Id-aadA7, and an adjacent mercury resistance module. Here, the uncharacterized part of SGI1-K was sequenced. Downstream of the mer module similar to that found in Tn21, a mosaic genetic structure was found, comprising (i) part of Tn1721 containing the tetracycline resistance genes tetR and tet(A); (ii) part of Tn5393 containing the streptomycin resistance genes strAB, IS1133, and a truncated tnpR gene; and (iii) a Tn3-like region containing the tnpR gene and the β-lactamase bla TEM-1 gene flanked by two IS26 elements in opposite orientations. The rightmost IS26 element was shown to be inserted into the S044 open reading frame of the SGI1 backbone. This variant MDR region was named SGI1-K1 according to the previously described variant SGI1-K. Other SGI1-K MDR regions due to different IS26 locations, inversion, and partial deletions were characterized and named SGI1-K2 to -K5. Two new SGI1 variants named SGI1-P1 and -P2 contained only the Tn3-like region comprising the β-lactamase bla TEM-1 gene flanked by the two IS26 elements inserted into the SGI1 backbone. Three other new variants harbored only one IS26 element inserted in place of the MDR region of SGI1 and were named SGI1-Q1 to -Q3. Thus, in serovar Kentucky, the SGI1 MDR region undergoes recombinational and insertional events of transposon and insertion sequences, resulting in a higher diversity of MDR gene clusters than previously reported and consequently a higher diversity of MDR phenotypes.

scholarly journals Diversity of the Tetracycline Mobilome within a Chinese Pig Manure Sample

2016 ◽  
Vol 82 (21) ◽  
pp. 6454-6462 ◽  
Author(s):  
Sébastien Olivier Leclercq ◽  
Chao Wang ◽  
Yaxin Zhu ◽  
Hai Wu ◽  
Xiaochen Du ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Efflux Pump ◽  
Genetic Resistance ◽  
Antibiotic Resistance Genes ◽  
Tetracycline Resistance ◽  
Animal Manure ◽  
Pig Manure ◽  
Tetracycline Antibiotics ◽  
Tetracycline Resistance Genes

ABSTRACTTetracycline antibiotics are widely used in livestock, and tetracycline resistance genes (TRG) are frequently reported in the manure of farmed animals. However, the diversity of TRG-carrying transposons in manure has still been rarely investigated. Using a culture-free functional metagenomic procedure, combined with large-insert library construction and sequencing, bioinformatic analyses, and functional experiments, we identified 17 distinct TRGs in a single pig manure sample, including two newtetgenes:tet(59), encoding a tetracycline efflux pump, andtet(W/N/W), encoding mosaic ribosomal protection. Our study also revealed six new TRG-carrying putative nonconjugative transposons: Tn5706-like transposon Tn6298, IS200/605-related transposon Tn6303, Tn3family transposon Tn6299, and three ISCR2-related transposons, Tn62300, Tn62301, and Tn62302.IMPORTANCEFertilization of agricultural fields with animal manure is believed to play a major role in antibiotic resistance dissemination in the environment. There is growing concern for the possible spread of antibiotic resistance from the environment to humans since genetic resistance determinants may be located in transposons and other mobile genetic elements potentially transferable to pathogens. Among the various antibiotic resistance genes found in manure, tetracycline resistance genes (TRGs) are some of the most common. The present study provides a detailed snapshot of the tetracycline mobilome in a single pig manure sample, revealing an unappreciated diversity of TRGs and potential TRG mobility vectors. Our precise identification of the TRG-carrying units will enable us to investigate in more details their mobility effectiveness.

scholarly journals Antimicrobial Use and Resistance in Swine Waste Treatment Systems

2006 ◽  
Vol 72 (12) ◽  
pp. 7813-7820 ◽  
Author(s):  
Archana Jindal ◽  
Svetlana Kocherginskaya ◽  
Asma Mehboob ◽  
Matthew Robert ◽  
Roderick I. Mackie ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Waste Treatment ◽  
Growth Promotion ◽  
Tetracycline Resistance ◽  
Land Application ◽  
Molecular Methods ◽  
23S Rrna ◽  
Organic Farm ◽  
Tetracycline Resistance Genes ◽  
Fecal Streptococci

ABSTRACT Chlortetracycline and the macrolide tylosin were identified as commonly used antimicrobials for growth promotion and prophylaxis in swine production. Resistance to these antimicrobials was measured throughout the waste treatment processes at five swine farms by culture-based and molecular methods. Conventional farm samples had the highest levels of resistance with both culture-based and molecular methods and had similar levels of resistance despite differences in antimicrobial usage. The levels of resistance in organic farm samples, where no antimicrobials were used, were very low by a culture-based method targeting fecal streptococci. However, when the same samples were analyzed with a molecular method detecting methylation of a specific nucleotide in the 23S rRNA that results in resistance to macrolides, lincosamides, and streptogramin B (MLSB), an unexpectedly high level of resistant rRNA (approximately 50%) was observed, suggesting that the fecal streptococci were not an appropriate target group to evaluate resistance in the overall microbial community and that background levels of MLSB resistance may be substantial. All of the feed samples tested, including those from the organic farm, contained tetracycline resistance genes. Generally, the same tetracycline resistance genes and frequency of detection were found in the manure and lagoon samples for each commercial farm. The levels of tetracycline and MLSB resistance remained high throughout the waste treatment systems, suggesting that the potential impact of land application of treated wastes and waste treatment by-products on environmental levels of resistance should be investigated further.

Abundances of Tetracycline Resistance Genes and Tetracycline Antibiotics during Anaerobic Digestion of Swine Waste

2019 ◽  
Vol 48 (1) ◽  
pp. 171-178 ◽  
Author(s):  
Melanie Couch ◽  
Getahun E. Agga ◽  
John Kasumba ◽  
Rohan R. Parekh ◽  
John H. Loughrin ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Resistance Genes ◽  
Tetracycline Resistance ◽  
Swine Waste ◽  
Tetracycline Antibiotics ◽  
Tetracycline Resistance Genes

scholarly journals Tetracycline Susceptibility Testing and Resistance Genes in Isolates of Acinetobacter baumannii-Acinetobacter calcoaceticus Complex from a U.S. Military Hospital

2009 ◽  
Vol 53 (6) ◽  
pp. 2693-2695 ◽  
Author(s):  
Kevin S. Akers ◽  
Katrin Mende ◽  
Heather C. Yun ◽  
Duane R. Hospenthal ◽  
Miriam L. Beckius ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Susceptibility Testing ◽  
Tetracycline Resistance ◽  
Acinetobacter Calcoaceticus ◽  
Multidrug Resistant ◽  
Military Hospital ◽  
Tetracycline Resistance Genes ◽  
Testing Method

ABSTRACT Infections with multidrug-resistant Acinetobacter baumannii-Acinetobacter calcoaceticus complex bacteria complicate the care of U.S. military personnel and civilians worldwide. One hundred thirty-three isolates from 89 patients at our facility during 2006 and 2007 were tested by disk diffusion, Etest, and broth microdilution for susceptibility to tetracycline, doxycycline, minocycline, and tigecycline. Minocycline was the most active in vitro, with 90% of the isolates tested susceptible. Susceptibilities varied significantly with the testing method. The acquired tetracycline resistance genes tetA, tetB, and tetA(39) were present in the isolates.

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