scholarly journals Construction of a fused operon consisting of a recA and kan (Kanamycin resistance) genes and regulation of its expression by the lexA gene

1982 ◽  
Vol 185 (1) ◽  
pp. 188-188
Author(s):  
Toru Miki ◽  
Hiromi Kumahara ◽  
Atsushi Nakazawa
Keyword(s):  
Resistance Genes ◽  
Kanamycin Resistance ◽  
Lexa Gene

scholarly journals IS26-Mediated Precise Excision of the IS26-aphA1a Translocatable Unit

mBio ◽  
2015 ◽  
Vol 6 (6) ◽  
Author(s):  
Christopher J. Harmer ◽  
Ruth M. Hall
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
High Frequency ◽  
Antibiotic Resistance Genes ◽  
Kanamycin Resistance ◽  
Gram Negative Bacteria ◽  
Critical Determinant ◽  
Gram Negative ◽  
Precise Excision ◽  
Replicative Transposition

ABSTRACTWe recently showed that, in the absence of RecA-dependent homologous recombination, the Tnp26 transposase catalyzes cointegrate formation via a conservative reaction between two preexisting IS26, and this is strongly preferred over replicative transposition to a new site. Here, the reverse reaction was investigated by assaying for precise excision of the central region together with a single IS26from a compound transposon bounded by IS26. In arecAmutant strain, Tn4352, a kanamycin resistance transposon carrying theaphA1agene, was stable. However, loss of kanamycin resistance due to precise excision of the translocatable unit (TU) from the closely related Tn4352B, leaving behind the second IS26, occurred at high frequency. Excision occurred when Tn4352B was in either a high- or low-copy-number plasmid. The excised circular segment, known as a TU, was detected by PCR. Excision required the IS26transposase Tnp26. However, the Tnp26 of only one IS26in Tn4352B was required, specifically the IS26downstream of theaphA1agene, and the excised TU included the active IS26. The frequency of Tn4352B TU loss was influenced by the context of the transposon, but the critical determinant of high-frequency excision was the presence of three G residues in Tn4352B replacing a single G in Tn4352.These G residues are located immediately adjacent to the two G residues at the left end of the IS26that is upstream of theaphA1agene. Transcription oftnp26was not affected by the additional G residues, which appear to enhance Tnp26 cleavage at this end.IMPORTANCEResistance to antibiotics limits treatment options. In Gram-negative bacteria, IS26plays a major role in the acquisition and dissemination of antibiotic resistance. IS257(IS431) and IS1216, which belong to the same insertion sequence (IS) family, mobilize resistance genes in staphylococci and enterococci, respectively. Many different resistance genes are found in compound transposons bounded by IS26, and multiply and extensively antibiotic-resistant Gram-negative bacteria often include regions containing several antibiotic resistance genes and multiple copies of IS26. We recently showed that in addition to replicative transposition, IS26can use a conservative movement mechanism in which an incoming IS26targets a preexisting one, and this reaction can create these regions. This mechanism differs from that of all the ISs examined in detail thus far. Here, we have continued to extend understanding of the reactions carried out by IS26by examining whether the reverse precise excision reaction is also catalyzed by the IS26transposase.

scholarly journals Prevalence of ColE1-Like Plasmids and Kanamycin Resistance Genes in Salmonella enterica Serovars

2010 ◽  
Vol 76 (20) ◽  
pp. 6707-6714 ◽  
Author(s):  
Chin-Yi Chen ◽  
Rebecca L. Lindsey ◽  
Terence P. Strobaugh ◽  
Jonathan G. Frye ◽  
Richard J. Meinersmann
Keyword(s):  
Resistance Genes ◽  
Salmonella Enterica ◽  
Critical Role ◽  
Antibiotic Resistance Genes ◽  
Kanamycin Resistance ◽  
Close Monitoring ◽  
Incompatibility Group ◽  
Serovar Typhimurium ◽  
Cole1 Plasmid ◽  
Primer Sets

ABSTRACT Multi-antimicrobial-resistant Salmonella enterica strains frequently carry resistance genes on plasmids. Recent studies focus heavily on large conjugative plasmids, and the role that small plasmids play in resistance gene transfer is largely unknown. To expand our previous studies in assessing the prevalence of the isolates harboring ColE1-like plasmids carrying the aph gene responsible for kanamycin resistance (Kanr) phenotypes, 102 Kanr Salmonella isolates collected through the National Antimicrobial Resistance Monitoring System (NARMS) in 2005 were screened by PCR using ColE1 primer sets. Thirty isolates were found to be positive for ColE1-like replicon. Plasmids from 23 isolates were able to propagate in Escherichia coli and were subjected to further characterization. Restriction mapping revealed three major plasmid groups found in three or more isolates, with each group consisting of two to three subtypes. The aph genes from the Kanr Salmonella isolates were amplified by PCR, sequenced, and showed four different aph(3′)-I genes. The distribution of the ColE1 plasmid groups in association with the aph gene, Salmonella serovar, and isolate source demonstrated a strong linkage of the plasmid with S. enterica serovar Typhimurium DT104. Due to their high copy number and mobility, the ColE1-like plasmids may play a critical role in transmission of antibiotic resistance genes among enteric pathogens, and these findings warrant a close monitoring of this plasmid incompatibility group.

scholarly journals Bacteriophages Isolated from Chicken Meat and the Horizontal Transfer of Antimicrobial Resistance Genes

2015 ◽  
Vol 81 (14) ◽  
pp. 4600-4606 ◽  
Author(s):  
Amira Shousha ◽  
Nattakarn Awaiwanont ◽  
Dmitrij Sofka ◽  
Frans J. M. Smulders ◽  
Peter Paulsen ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Horizontal Transfer ◽  
Tetracycline Resistance ◽  
Kanamycin Resistance ◽  
Chicken Meat ◽  
Resistant Bacteria ◽  
Content Type ◽  
E Coli ◽  
Antimicrobial Resistance Genes

ABSTRACTAntimicrobial resistance in microbes poses a global and increasing threat to public health. The horizontal transfer of antimicrobial resistance genes was thought to be due largely to conjugative plasmids or transposons, with only a minor part being played by transduction through bacteriophages. However, whole-genome sequencing has recently shown that the latter mechanism could be highly important in the exchange of antimicrobial resistance genes between microorganisms and environments. The transfer of antimicrobial resistance genes by phages could underlie the origin of resistant bacteria found in food. We show that chicken meat carries a number of phages capable of transferring antimicrobial resistance. Of 243 phages randomly isolated from chicken meat, about a quarter (24.7%) were able to transduce resistance to one or more of the five antimicrobials tested intoEscherichia coliATCC 13706 (DSM 12242). Resistance to kanamycin was transduced the most often, followed by that to chloramphenicol, with four phages transducing tetracycline resistance and three transducing ampicillin resistance. Phages able to transduce antimicrobial resistance were isolated from 44% of the samples of chicken meat that we tested. The statistically significant (P= 0.01) relationship between the presence of phages transducing kanamycin resistance andE. coliisolates resistant to this antibiotic suggests that transduction may be an important mechanism for transferring kanamycin resistance toE. coli. It appears that the transduction of resistance to certain antimicrobials, e.g., kanamycin, not only is widely distributed inE. coliisolates found on meat but also could represent a major mechanism for resistance transfer. The result is of high importance for animal and human health.

scholarly journals Phylogenetic Groups and Antimicrobial Resistance Genes in Escherichia coli from Different Meat Species

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1543
Author(s):  
Angelika Sacher-Pirkelbauer ◽  
Daniela Klein-Jöbstl ◽  
Dmitrij Sofka ◽  
Anne-Béatrice Blanc-Potard ◽  
Friederike Hilbert
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Tetracycline Resistance ◽  
Kanamycin Resistance ◽  
Phylogenetic Group ◽  
Phylogenetic Groups ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Meat Species

Escherichia coli isolated from meat of different animal species may harbour antimicrobial resistance genes and may thus be a threat to human health. The objectives of this study were to define antimicrobial resistance genes in E. coli isolates from pork, beef, chicken- and turkey meat and analyse whether their resistance genotypes associated with phylogenetic groups or meat species. A total number of 313 E. coli samples were isolated using standard cultural techniques. In 98% of resistant isolates, a dedicated resistance gene could be identified by PCR. Resistance genes detected were tet(A) and tet(B) for tetracycline resistance, strA and aadA1 for streptomycin resistance, sulI and sulII for resistance against sulphonamides, dfr and aphA for kanamycin resistance and blaTEM for ampicillin resistance. One stx1 harbouring E. coli isolated from pork harboured the tet(A) gene and belonged to phylogenetic group B2, whilst another stx1 positive isolate from beef was multi-resistant and tested positive for blaTEM,aphA, strA–B, sulII, and tet(A) and belonged to phylogenetic group A. In conclusion, the distribution of resistance elements was almost identical and statistically indifferent in isolates of different meat species. Phylogenetic groups did not associate with the distribution of resistance genes and a rather low number of diverse resistance genes were detected. Most E. coli populations with different resistance genes against one drug often revealed statistically significant different MIC values.

scholarly journals Molecular Basis of Resistance to Macrolides and Other Antibiotics in Commensal Viridans Group Streptococci and Gemella spp. and Transfer of Resistance Genes to Streptococcus pneumoniae

2004 ◽  
Vol 48 (9) ◽  
pp. 3462-3467 ◽  
Author(s):  
Paula Cerdá Zolezzi ◽  
Leticia Millán Laplana ◽  
Carmen Rubio Calvo ◽  
Pilar Goñi Cepero ◽  
Melisa Canales Erazo ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Resistance Genes ◽  
Molecular Basis ◽  
Kanamycin Resistance ◽  
Mechanisms Of Resistance ◽  
M Gene ◽  
Streptococcus Mitis ◽  
E Gene ◽  
High Level ◽  
Viridans Group Streptococci

ABSTRACT We assessed the mechanisms of resistance to macrolide-lincosamide-streptogramin B (MLSB) antibiotics and related antibiotics in erythromycin-resistant viridans group streptococci (n = 164) and Gemella spp. (n = 28). The macrolide resistance phenotype was predominant (59.38%); all isolates with this phenotype carried the mef(A) or mef(E) gene, with mef(E) being predominant (95.36%). The erm(B) gene was always detected in strains with constitutive and inducible MLSB resistance and was combined with the mef(A/E) gene in 47.44% of isolates. None of the isolates carried the erm(A) subclass erm(TR), erm(A), or erm(C) genes. The mel gene was detected in all but four strains carrying the mef(A/E) gene. The tet(M) gene was found in 86.90% of tetracycline-resistant isolates and was strongly associated with the presence of the erm(B) gene. The catpC194 gene was detected in seven chloramphenicol-resistant Streptococcus mitis isolates, and the aph(3′)-III gene was detected in four viridans group streptococcal isolates with high-level kanamycin resistance. The intTn gene was found in all isolates with the erm(B), tet(M), aph(3′)-III, and catpC194 gene. The mef(E) and mel genes were successfully transferred from both groups of bacteria to Streptococcus pneumoniae R6 by transformation. Viridans group streptococci and Gemella spp. seem to be important reservoirs of resistance genes.

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