The Clostridium perfringens Tet P determinant comprises two overlapping genes: tetA(P), which mediates active tetracycline efflux, and tetB(P), which is related to the ribosomal protection family of tetracycline-resistance determinants

1994 ◽  
Vol 11 (2) ◽  
pp. 403-415 ◽  
Author(s):  
Joan Sloan ◽  
Laura M. McMurry ◽  
Dena Lyras ◽  
Stuart B. Levy ◽  
Julian I. Rood
Keyword(s):  
Clostridium Perfringens ◽  
Tetracycline Resistance ◽  
Overlapping Genes ◽  
Resistance Determinants ◽  
Ribosomal Protection

scholarly journals In Vitro and In Vivo Antibacterial Activities of a Novel Glycylcycline, the 9-t-Butylglycylamido Derivative of Minocycline (GAR-936)

1999 ◽  
Vol 43 (4) ◽  
pp. 738-744 ◽  
Author(s):  
P. J. Petersen ◽  
N. V. Jacobus ◽  
W. J. Weiss ◽  
P. E. Sum ◽  
R. T. Testa
Keyword(s):  
Anaerobic Bacteria ◽  
Tetracycline Resistance ◽  
Protective Effects ◽  
Gram Negative ◽  
E Coli ◽  
Resistance Determinants ◽  
Aerobic And Anaerobic ◽  
Ribosomal Protection

ABSTRACT The 9-t-butylglycylamido derivative of minocycline (TBG-MINO) is a recently synthesized member of a novel group of antibiotics, the glycylcyclines. This new derivative, like the first glycylcyclines, theN,N-dimethylglycylamido derivative of minocycline and 6-demethyl-6-deoxytetracycline, possesses activity against bacterial isolates containing the two major determinants responsible for tetracycline resistance: ribosomal protection and active efflux. The in vitro activities of TBG-MINO and the comparative agents were evaluated against strains with characterized tetracycline resistance as well as a spectrum of recent clinical aerobic and anaerobic gram-positive and gram-negative bacteria. TBG-MINO, with an MIC range of 0.25 to 0.5 μg/ml, showed good activity against strains expressing tet(M) (ribosomal protection), tet(A), tet(B),tet(C), tet(D), and tet(K) (efflux resistance determinants). TBG-MINO exhibited similar activity against methicillin-resistant Staphylococcus aureus (MRSA), penicillin-resistant streptococci, and vancomycin-resistant enterococci (MICs at which 90% of strains are inhibited, ≤0.5 μg/ml). TBG-MINO exhibited activity against a wide diversity of gram-negative aerobic and anaerobic bacteria, most of which were less susceptible to tetracycline and minocycline. The in vivo protective effects of TBG-MINO were examined against acute lethal infections in mice caused by Escherichia coli, S. aureus, andStreptococcus pneumoniae isolates. TBG-MINO, administered intravenously, demonstrated efficacy against infections caused byS. aureus including MRSA strains and strains containingtet(K) or tet(M) resistance determinants (median effective doses [ED50s], 0.79 to 2.3 mg/kg of body weight). TBG-MINO demonstrated efficacy against infections caused by tetracycline-sensitive E. coli strains as well asE. coli strains containing either tet(M) or the efflux determinant tet(A), tet(B), ortet(C) (ED50s, 1.5 to 3.5 mg/kg). Overall, TBG-MINO shows antibacterial activity against a wide spectrum of gram-positive and gram-negative aerobic and anaerobic bacteria including strains resistant to other chemotherapeutic agents. The in vivo protective effects, especially against infections caused by resistant bacteria, corresponded with the in vitro activity of TBG-MINO.

scholarly journals Transcriptional Analysis of thetet(P) Operon from Clostridium perfringens

2001 ◽  
Vol 183 (24) ◽  
pp. 7110-7119 ◽  
Author(s):  
Priscilla A. Johanesen ◽  
Dena Lyras ◽  
Trudi L. Bannam ◽  
Julian I. Rood
Keyword(s):  
Clostridium Perfringens ◽  
Gene Deletion ◽  
Transmembrane Protein ◽  
Tetracycline Resistance ◽  
Transcriptional Analysis ◽  
Start Codon ◽  
Control Element ◽  
Overlapping Genes ◽  
Reporter Construct ◽  
P Gene

ABSTRACT The Clostridium perfringens tetracycline resistance determinant from the 47-kb conjugative R-plasmid pCW3 is unique in that it consists of two overlapping genes, tetA(P) andtetB(P), which mediate resistance by different mechanisms. Detailed transcriptional analysis has shown that the inducible tetA(P) and tetB(P) genes comprise an operon that is transcribed from a single promoter, P3, located 529 bp upstream of the tetA(P) start codon. Deletion of P3 or alteration of the spacing between the −35 and −10 regions significantly reduced the level of transcription in a reporter construct. Induction was shown to be mediated at the level of transcription. Unexpectedly, a factor-independent terminator, T1, was detected downstream of P3 but before the start of thetetA(P) gene. Deletion or mutation of this terminator led to increased read-through transcription in the reporter construct. It is postulated that the T1 terminator is an intrinsic control element of the tet(P) operon and that it acts to prevent the overexpression of the TetA(P) transmembrane protein, even in the presence of tetracycline.

scholarly journals tISCpe8, an IS1595-Family Lincomycin Resistance Element Located on a Conjugative Plasmid in Clostridium perfringens

2009 ◽  
Vol 191 (20) ◽  
pp. 6345-6351 ◽  
Author(s):  
Dena Lyras ◽  
Vicki Adams ◽  
Susan A. Ballard ◽  
Wee L. Teng ◽  
Pauline M. Howarth ◽  
...  
Keyword(s):  
Clostridium Perfringens ◽  
Antibiotic Resistance Genes ◽  
Tetracycline Resistance ◽  
Conjugative Plasmid ◽  
Insertion Sequences ◽  
Genetic Element ◽  
Significant Similarity ◽  
Conjugative Transposon ◽  
Resistance Determinants ◽  
Lincomycin Resistance

ABSTRACT Clostridium perfringens is a normal gastrointestinal organism that is a reservoir for antibiotic resistance genes and can potentially act as a source from which mobile elements and their associated resistance determinants can be transferred to other bacterial pathogens. Lincomycin resistance in C. perfringens is common and is usually encoded by erm genes that confer macrolide-lincosamide-streptogramin B resistance. In this study we identified strains that are lincomycin resistant but erythromycin sensitive and showed that the lincomycin resistance determinant was plasmid borne and could be transferred to other C. perfringens isolates by conjugation. The plasmid, pJIR2774, is the first conjugative C. perfringens R-plasmid to be identified that does not confer tetracycline resistance. Further analysis showed that resistance was encoded by the lnuP gene, which encoded a putative lincosamide nucleotidyltransferase and was located on tISCpe8, a functional transposable genetic element that was a member of the IS1595 family of transposon-like insertion sequences. This element had significant similarity to the mobilizable lincomycin resistance element tISSag10 from Streptococcus agalactiae. Like tISSag10, tISCpe8 carries a functional origin of transfer within the resistance gene, allowing the element to be mobilized by the conjugative transposon Tn916. The similarity of these elements and the finding that they both contain an oriT-like region support the hypothesis that conjugation may result in the movement of DNA modules that are not obviously mobile since they are not linked to conjugation or mobilization functions. This process likely plays a significant role in bacterial adaptation and evolution.

Antibiotic survey ofLactococcus lactisstrains to six antibiotics by Etest, and establishment of new susceptibility-resistance cut-off values

2007 ◽  
Vol 74 (3) ◽  
pp. 262-268 ◽  
Author(s):  
Ana Belén Flórez ◽  
Morten Danielsen ◽  
Jenni Korhonen ◽  
Joanna Zycka ◽  
Atte von Wright ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Inhibitory Concentration ◽  
Tetracycline Resistance ◽  
Large Collection ◽  
Bacterial Strains ◽  
Resistance Determinants ◽  
Resistant Strains ◽  
Geographical Locations ◽  
S Genes ◽  
Acquired Antibiotic Resistance

In order to establish cut-off values forLactococcus lactisto six antibiotics to distinguish susceptible and intrinsically resistant strains from those having acquired resistances, the minimum inhibitory concentration (MIC) of tetracycline, erythromycin, clindamycin, streptomycin, chloramphenicol and vancomycin was determined in 93 differentLc. lactisstrains using the Etest. These bacterial strains were originally isolated from dairy and animal sources in widely separated geographical locations. Cut-offs were defined on the basis of the distribution of the MICs frequency of the studied antibiotics, which in the absence of acquired determinants should approach to a normal statistical distribution. In general, the new cut-off values proposed in this study are higher than previously defined (European Commission, 2005. The EFSA Journal 223, 1–12). Based on these new values, all the strains tested were susceptible to erythromycin, chloramphenicol and vancomycin, and 79 susceptible to all six antibiotics. However, 11 strains (around 12%) were considered resistant to tetracycline (six of which had been identified after screening of a large collection of lactococci strains for tetracycline resistance) and five (5·4%) resistant to streptomycin. Of these, two fish isolates proved to be resistance to both tetracycline and streptomycin. From the tetracycline resistant strains,tet(M) and mosaictet(L/S) genes were amplified by PCR, demonstrating they harboured acquired antibiotic resistance determinants.

scholarly journals A Role for Tetracycline Selection in Recent Evolution of Agriculture-Associated Clostridium difficile PCR Ribotype 078

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Kate E. Dingle ◽  
Xavier Didelot ◽  
T. Phuong Quan ◽  
David W. Eyre ◽  
Nicole Stoesser ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Evolutionary History ◽  
Selective Pressure ◽  
Tetracycline Resistance ◽  
Clonal Expansion ◽  
Human Pathogen ◽  
Content Type ◽  
Resistance Determinants ◽  
Ribotype 078 ◽  
Human Infections

ABSTRACT The increasing clinical importance of human infections (frequently severe) caused by Clostridium difficile PCR ribotype 078 (RT078) was first reported in 2008. The severity of symptoms (mortality of ≤30%) and the higher proportion of infections among community and younger patients raised concerns. Farm animals, especially pigs, have been identified as RT078 reservoirs. We aimed to understand the recent changes in RT078 epidemiology by investigating a possible role for antimicrobial selection in its recent evolutionary history. Phylogenetic analysis of international RT078 genomes (isolates from 2006 to 2014, n = 400), using time-scaled, recombination-corrected, maximum likelihood phylogenies, revealed several recent clonal expansions. A common ancestor of each expansion had independently acquired a different allele of the tetracycline resistance gene tetM. Consequently, an unusually high proportion (76.5%) of RT078 genomes were tetM positive. Multiple additional tetracycline resistance determinants were also identified (including efflux pump tet40), frequently sharing a high level of nucleotide sequence identity (up to 100%) with sequences found in the pig pathogen Streptococcus suis and in other zoonotic pathogens such as Campylobacter jejuni and Campylobacter coli. Each RT078 tetM clonal expansion lacked geographic structure, indicating rapid, recent international spread. Resistance determinants for C. difficile infection-triggering antimicrobials, including fluoroquinolones and clindamycin, were comparatively rare in RT078. Tetracyclines are used intensively in agriculture; this selective pressure, plus rapid, international spread via the food chain, may explain the increased RT078 prevalence in humans. Our work indicates that the use of antimicrobials outside the health care environment has selected for resistant organisms, and in the case of RT078, has contributed to the emergence of a human pathogen. IMPORTANCE Clostridium difficile PCR ribotype 078 (RT078) has multiple reservoirs; many are agricultural. Since 2005, this genotype has been increasingly associated with human infections in both clinical settings and the community. Investigations of RT078 whole-genome sequences revealed that tetracycline resistance had been acquired on multiple independent occasions. Phylogenetic analysis revealed a rapid, recent increase in numbers of closely related tetracycline-resistant RT078 (clonal expansions), suggesting that tetracycline selection has strongly influenced its recent evolutionary history. We demonstrate recent international spread of emergent, tetracycline-resistant RT078. A similar tetracycline-positive clonal expansion was also identified in unrelated nontoxigenic C. difficile, suggesting that this process may be widespread and may be independent of disease-causing ability. Resistance to typical C. difficile infection-associated antimicrobials (e.g., fluoroquinolones, clindamycin) occurred only sporadically within RT078. Selective pressure from tetracycline appears to be a key factor in the emergence of this human pathogen and the rapid international dissemination that followed, plausibly via the food chain.

scholarly journals Genetic organization and distribution of tetracycline resistance determinants in Clostridium perfringens.

1996 ◽  
Vol 40 (11) ◽  
pp. 2500-2504 ◽  
Author(s):  
D Lyras ◽  
J I Rood
Keyword(s):  
Clostridium Perfringens ◽  
Transmembrane Protein ◽  
Tetracycline Resistance ◽  
Wide Distribution ◽  
Pcr Analysis ◽  
Nucleotide Sequence Analysis ◽  
Significant Similarity ◽  
Active Efflux ◽  
P Gene ◽  
Carboxy Terminal

The Tet P determinant from the conjugative Clostridium perfringens R plasmid pCW3 two functional overlapping tetracycline resistance genes, tetA(P) and tetB(P). The tetA(P) gene encodes a putative 46-kDa transmembrane protein which mediates active efflux of tetracycline from the cell, while tetB(P) encodes a putative 72.6-kDa protein which has significant similarity to Tet M-like tetracycline resistance proteins (J. Sloan, L.M. McMurry, D. Lyras, S. B. Levy, and J. I. Rood, Mol. Microbiol. 11:403-415, 1994). In the present study, hybridization and PCR analysis of 81 tetracycline-resistant isolates of C. perfringens showed that they all carried the tetA(P) gene. Most of these isolates (93%) carried a second tetracycline resistance gene, with 53% carrying tetB(P) and 40% carrying a tet(M)-like gene. Despite the wide distribution of the tetB(P) and tet(M) genes, no isolate which carried both of these determinants was detected. In isolates that carried both tetA(P) and tetB(P) these genes overlapped, as in pCW3. Isolates carrying this combination of genes originated from diverse geographical locations and environmental sources. The single Clostridium paraputrificum isolate examined carried tetA(P), indicating that this gene is not confined to C.perfringens. However, neither tetA(P) nor tetB(P) was detected in the nine Clostridium difficile isolates tested. Nucleotide sequence analysis of isolates lacking tetB(P) revealed that they contained the tetA408(P) gene, which lacked the codons for the 12 carboxy-terminal amino acids of the TetA(P) protein.

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