scholarly journals Multidrug resistance pump AcrAB-TolC is required for high-level, Tet(A)-mediated tetracycline resistance in Escherichia coli

2006 ◽  
Vol 58 (1) ◽  
pp. 31-36 ◽  
Author(s):  
R. E. de Cristobal
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Tetracycline Resistance ◽  
High Level

scholarly journals Complete Nucleotide Sequence of a Novel Plasmid Bearing the High-Level Tigecycline Resistance Gene tet(X4)

2019 ◽  
Vol 63 (11) ◽  
Author(s):  
Liang-Xing Fang ◽  
Chong Chen ◽  
Dong-Ling Yu ◽  
Ruan-Yang Sun ◽  
Chao-Yue Cui ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Sequence Analysis ◽  
Nucleotide Sequence ◽  
Complete Nucleotide Sequence ◽  
Hybrid Plasmid ◽  
Content Type ◽  
Clinically Significant ◽  
High Level ◽  
Plasmid Backbone

ABSTRACT We reported the complete nucleotide sequence of a tet(X4)-carrying plasmid, pSTB20-1T, from a tigecycline-resistant Escherichia coli isolate in China. Sequence analysis indicated that pSTB20-1T contains a hybrid plasmid backbone and a tet(X4)-containing multidrug resistance region, likely originated through recombination of multiple plasmids. tet(X4) was flanked by two ISCR2, which may be responsible for tet(X4) mobilization. The occurrence and transmission of this novel hybrid plasmid may exacerbate the spread of the clinically significant tet(X4) gene.

scholarly journals A Combination of sbmA and tolC Mutations in Escherichia coli K-12 Tn10-Carrying Strains Results in Hypersusceptibility to Tetracycline

2007 ◽  
Vol 190 (4) ◽  
pp. 1491-1494 ◽  
Author(s):  
Ricardo E. de Cristóbal ◽  
Paula A. Vincent ◽  
Raúl A. Salomón
Keyword(s):  
Escherichia Coli ◽  
Double Mutant ◽  
Phenotypic Expression ◽  
Tetracycline Resistance ◽  
Additive Effect ◽  
Complete Suppression ◽  
High Level ◽  
K 12 ◽  
Level Resistance

ABSTRACT Previously, we demonstrated that Escherichia coli tolC mutations reduce the high-level resistance to tetracycline afforded by the transposon Tn10-encoded TetA pump from resistance at 200 μg/ml to resistance at 40 μg/ml. In this study, we found that the addition of an sbmA mutation to a tolC::Tn10 mutant exacerbates this phenotype: the double mutant did not form colonies, even in the presence of tetracycline at a concentration as low as 5 μg/ml. Inactivation of sbmA alone partially inhibited high-level tetracycline resistance, from resistance at 200 μg/ml to resistance at 120 μg/ml. There thus appears to be an additive effect of the mutations, resulting in almost complete suppression of the phenotypic expression of Tn10 tetracycline resistance.

scholarly journals Overexpression of the Escherichia coli sugE Gene Confers Resistance to a Narrow Range of Quaternary Ammonium Compounds

2002 ◽  
Vol 184 (9) ◽  
pp. 2543-2545 ◽  
Author(s):  
Yong Joon Chung ◽  
Milton H. Saier
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Multidrug Resistance ◽  
Quaternary Ammonium ◽  
Narrow Range ◽  
Quaternary Ammonium Compounds ◽  
High Level Expression ◽  
Small Multidrug Resistance ◽  
High Level ◽  
Ammonium Compounds

ABSTRACT SugE of Escherichia coli, first identified as a suppressor of groEL mutations but a member of the small multidrug resistance family, has not previously been shown to confer a drug resistance phenotype. We show that high-level expression of sugE leads to resistance to a subset of toxic quaternary ammonium compounds.

scholarly journals Gene Cluster Conferring Streptomycin, Sulfonamide, and Tetracycline Resistance inEscherichia coliO157:H7 Phage Types 23, 45, and 67

2011 ◽  
Vol 77 (5) ◽  
pp. 1900-1903 ◽  
Author(s):  
K. Ziebell ◽  
R. P. Johnson ◽  
A. M. Kropinski ◽  
R. Reid-Smith ◽  
R. Ahmed ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Gene Cluster ◽  
Tetracycline Resistance ◽  
Phage Types

ABSTRACTMultidrug resistance to streptomycin, sulfonamide, and tetracycline (AMR-SSuT) was identified in 156 of 171 isolates ofEscherichia coliO157:H7 of phage types 23, 45, and 67. In 154 AMR-SSuT isolates, resistance was encoded bystrA,strB,sul2, andtet(B), which in 59 of 63 tested isolates were found clustered together on the chromosome within thecdiAlocus.

scholarly journals Effects of Ribosomal Protein S10 Flexible Loop Mutations on Tetracycline and Tigecycline Susceptibility of Escherichia coli

2021 ◽  
Vol 12 ◽  
Author(s):  
Norbert Izghirean ◽  
Claudia Waidacher ◽  
Clemens Kittinger ◽  
Miriam Chyba ◽  
Günther Koraimann ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Parent Strain ◽  
Ribosomal Subunit ◽  
Tetracycline Resistance ◽  
E Coli ◽  
Growth Defects ◽  
Flexible Loop ◽  
Cold Sensitive ◽  
High Level

Tigecycline is a tetracycline derivative that is being used as an antibiotic of last resort. Both tigecycline and tetracycline bind to the small (30S) ribosomal subunit and inhibit translation. Target mutations leading to resistance to these antibiotics have been identified both in the 16S ribosomal RNA and in ribosomal proteins S3 and S10 (encoded by the rpsJ gene). Several different mutations in the S10 flexible loop tip residue valine 57 (V57) have been observed in tigecycline-resistant Escherichia coli isolates. However, the role of these mutations in E. coli has not yet been characterized in a defined genetic background. In this study, we chromosomally integrated 10 different rpsJ mutations into E. coli, resulting in different exchanges or a deletion of S10 V57, and investigated the effects of the mutations on growth and tigecycline/tetracycline resistance. While one exchange, V57K, decreased the minimal inhibitory concentration (MIC) (Etest) to tetracycline to 0.75 μg/ml (compared to 2 μg/ml in the parent strain) and hence resulted in hypersensitivity to tetracycline, most exchanges, including the ones reported previously in resistant isolates (V57L, V57D, and V57I) resulted in slightly increased MICs to tigecycline and tetracycline. The strongest increase was observed for the V57L mutant, with a MIC (Etest) to tigecycline of 0.5 μg/ml (compared to 0.125 μg/ml in the parent strain) and a MIC to tetracycline of 4.0 μg/ml. Nevertheless, none of these exchanges increased the MIC to the extent observed in previously described clinical tigecycline-resistant isolates. We conclude that, next to S10 mutations, additional mutations are necessary in order to reach high-level tigecycline resistance in E. coli. In addition, our data reveal that mutants carrying S10 V57 exchanges or deletion display growth defects and, in most cases, also thermosensitivity. The defects are particularly strong in the V57 deletion mutant, which is additionally cold-sensitive. We hypothesize that the S10 loop tip residue is critical for the correct functioning of S10. Both the S10 flexible loop and tigecycline are in contact with helix h31 of the 16S rRNA. We speculate that exchanges or deletion of V57 alter the positioning of h31, thereby influencing both tigecycline binding and S10 function.

scholarly journals Susceptibility to antibiotics in escherichiae isolated in a multidisciplinary medical centre

2016 ◽  
Vol 65 (4) ◽  
pp. 83-89
Author(s):  
Nadezda S. Kozlova ◽  
Natalia E. Barantsevich ◽  
Elena P. Barantsevich
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Antimicrobial Resistance ◽  
Antimicrobial Agents ◽  
E Coli ◽  
Microdilution Method ◽  
Carbapenem Resistant ◽  
Resistant Strains ◽  
High Level

Relevance. Antimicrobial resistance in nosocomial strains currently presents a very important problem.  Aim of the study: Study of antibiotic resistance in Escherichia coli, isolated in a multidisciplinary centre.  Materials and Methods. Susceptibility of 151 E. coli strains to 15 antibiotics was studied by microdilution method. Results. The majority of the studied strains were resistant to antibiotics, including: ampicillin (57.0%), ciprofloxacin and moxifloxacin (42.4% each), III and IV generation cephalosporins (37.1% and 34.4%, respectively) and gentamycin (29.1%). The highest activity against E. coliwas shown for carbapenems (resistance to erthapenem – 2.6%, meropenem – 0.7%), in particular, for imipenem – no strains resistant to this drug were isolated. Resistance to amikacin and phosphomycin was low: 3.3% and 1.3% respectively. Wide diversity of antibiotic resistance spectra was revealed in studied strains, with a high level of multidrug resistance (48.0%). Conclusion. Study of susceptibility to antimicrobial agents in E. coli, isolated in a multidisciplinary centre, showed predominance of resistant strains with a high level of multidrug resistance. The appearance of carbapenem-resistant strains in a multidisciplinary centre presents a rising problem.

Cloning of tetracycline-resistance genes from various strains of Clostridium perfringens and expression in Escherichia coli

1992 ◽  
Vol 38 (3) ◽  
pp. 215-221 ◽  
Author(s):  
Nitin K. Saksena ◽  
Nicole Truffaut
Keyword(s):  
Escherichia Coli ◽  
Gene Cloning ◽  
Key Words ◽  
Clostridium Perfringens ◽  
Resistance Genes ◽  
Tetracycline Resistance ◽  
Tetracycline Resistance Genes ◽  
Expression In Escherichia Coli ◽  
Large Plasmids ◽  
High Level

One hundred strains of Clostridium perfringens and 52 strains of other Clostridia of human and animal origins were screened for tetracycline resistance. Fifty-six strains were resistant to tetracycline in the C. perfringens group. Ten strains were selected for their high level of resistance. In all of them, the tetracycline-resistance genes were found to be residing in large plasmids of about 50 kb, all showing homologies. Several tetracycline-resistance genes from plasmids of various strains of C. perfringens were cloned in plasmid pUC19 and the resistance was expressed in Escherichia coli. Hybridization analysis showed these genes to be homologous among themselves and also to tetP gene from the PCW3-type plasmid. Key words: tetracycline resistance, Clostridium perfringens, gene cloning, recombinant plasmids.

scholarly journals Escherichia coli as Possible Agents of Spread of Multidrug Resistance in Port Harcourt, Rivers State.

2019 ◽  
Vol 4 (1) ◽  
pp. 16-21
Author(s):  
Kome Otokunefor ◽  
Victor Ogechi Osogho ◽  
Chijindu Precious Nwankwo
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Clinical Isolates ◽  
Human Populations ◽  
Plasmid Curing ◽  
Port Harcourt ◽  
Genes Encoding ◽  
Mar Index ◽  
High Level

AbstractMultidrug resistance (MDR) continues to be a growing global issue. The problem of MDR is fuelled in part by the spread of the genes encoding resistance horizontally which is linked particularly to conjugation involving plasmids. Studies have demonstrated the presence of plasmids in drug resistant isolates, few have shown a link between these plasmids and drug resistance via plasmid curing especially in our locale. This study set out to explore this link inEscherichia coliisolates from Port Harcourt, Nigeria. Plasmid curing was done on a selection of clinical and non-clinical bacteria using acridine orange and antibiotic susceptibility testing carried out on both cured and uncured variants. Data generated was analysed to ascertain the multiple antibiotic resistance (MAR) index and MDR of each isolate. Data was then compared to ascertain effects of plasmid curing on antibiotic resistance of the isolates. Results revealed a decrease in resistance to 7 of 8 antibiotics following plasmid curing. The highest change was noted in ceftazidime (40%), followed by ofloxacin (26.7%). Plasmid curing caused a shift in MAR index values of isolates from higher to lower indices. At MAR index values of ≤0.25 occurrence increased from 5% to 36.7% while at MAR index values ≥0.75, occurrence reduced from 29.9% to 10.0%. A reduction in the degree of MDR was noted (from 55% to 36.7%). Strikingly, the reduction in MDR level of non-clinical isolates was 30% as opposed to 3.4% in the clinical isolates. This study shows a link between plasmids and antibiotic resistance. For the non-clinical isolates, the high-level link between MDR and plasmid carriage could indicate a higher use of antimicrobials in non-clinical rather than clinical settings. Additionally, it could be an indicator for a higher risk of the transfer of MDR determinants from non-clinical sources to human populations in our locale.

scholarly journals Incidence of Antibiotic Resistance in Campylobacter jejuni Isolated in Alberta, Canada, from 1999 to 2002, with Special Reference to tet(O)-Mediated Tetracycline Resistance

2004 ◽  
Vol 48 (9) ◽  
pp. 3442-3450 ◽  
Author(s):  
Amera Gibreel ◽  
Dobryan M. Tracz ◽  
Lisa Nonaka ◽  
Trinh M. Ngo ◽  
Sean R. Connell ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Campylobacter Jejuni ◽  
Tetracycline Resistance ◽  
Clinical Isolates ◽  
Nucleotide Substitutions ◽  
The Past ◽  
Genes Encoding ◽  
Large Plasmids ◽  
High Level

ABSTRACT Of 203 human clinical isolates of Campylobacter jejuni from Alberta, Canada (1999 to 2002), 101 isolates (50%) were resistant to at least 64 μg of tetracycline/ml, with four isolates exhibiting higher levels of tetracycline resistance (512 μg/ml). In total, the MICs for 37% of tetracycline-resistant isolates (256 to 512 μg/ml) were higher than those previously reported in C. jejuni (64 to 128 μg/ml). In the tetracycline-resistant clinical isolates, 67% contained plasmids and all contained the tet(O) gene. Four isolates resistant to high levels of tetracycline (MIC = 512 μg/ml) contained plasmids carrying the tet(O) gene, which could be transferred to other isolates of C. jejuni. The tetracycline MICs for transconjugants were comparable to those of the donors. Cloning of tet(O) from the four high-level tetracycline-resistant isolates conferred an MIC of 32 μg/ml for Escherichia coli DH5α. In contrast, transfer to a strain of C. jejuni by using mobilization conferred an MIC of 128 μg/ml. DNA sequence analysis determined that the tet(O) genes encoding lower MICs (64 to 128 μg/ml) were identical to one other, although the tet(O) genes encoding a 512-μg/ml MIC demonstrated several nucleotide substitutions. The quinolone resistance determining region of four ciprofloxacin-resistant isolates (2%) was analyzed, and resistance was associated with a chromosomal mutation in the gyrA gene resulting in a Thr-86-Ile substitution. In addition, six kanamycin-resistant isolates contained large plasmids that carry the aphA-3 marker coding for 3′-aminoglycoside phosphotransferase. Resistance to erythromycin was not detected in 203 isolates. In general, resistance to most antibiotics in C. jejuni remains low, except for resistance to tetracycline, which has increased from about 8 to 50% over the past 20 years.

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