scholarly journals Phenotypic and genetic barriers to establishment of horizontally transferred genes encoding ribosomal protection proteins

2021 ◽  
Author(s):  
Kavita Yadav ◽  
Linnéa Garoff ◽  
Douglas L Huseby ◽  
Diarmaid Hughes
Keyword(s):  
Tetracycline Resistance ◽  
Nucleotide Composition ◽  
E Coli ◽  
Low Level ◽  
Wide Range ◽  
Genetic Barriers ◽  
Genes Encoding ◽  
High Level ◽  
Level Resistance ◽  
Ribosomal Protection

Abstract Background Ribosomal protection proteins (RPPs) interact with bacterial ribosomes to prevent inhibition of protein synthesis by tetracycline. RPP genes have evolved from a common ancestor into at least 12 distinct classes and spread by horizontal genetic transfer into a wide range of bacteria. Many bacterial genera host RPP genes from multiple classes but tet(M) is the predominant RPP gene found in Escherichia coli. Objectives We asked whether phenotypic barriers (low-level resistance, high fitness cost) might constrain the fixation of other RPP genes in E. coli. Methods We expressed a diverse set of six different RPP genes in E. coli, including tet(M), and quantified tetracycline susceptibility and growth phenotypes as a function of expression level, and evolvability to overcome identified phenotypic barriers. Results The genes tet(M) and tet(Q) conferred high-level tetracycline resistance without reducing fitness; tet(O) and tet(W) conferred high-level resistance but significantly reduced growth fitness; tetB(P) conferred low-level resistance and while mutants conferring high-level resistance were selectable these had reduced growth fitness; otr(A) did not confer resistance and resistant mutants could not be selected. Evolution experiments suggested that codon usage patterns in tet(O) and tet(W), and transcriptional silencing associated with nucleotide composition in tetB(P), accounted for the observed phenotypic barriers. Conclusions With the exception of tet(Q), the data reveal significant phenotypic and genetic barriers to the fixation of additional RPP genes in E. coli.

scholarly journals High and low level tetracycline resistance inShigella sonnei

1978 ◽  
Vol 81 (1) ◽  
pp. 131-138 ◽  
Author(s):  
W. A. Hawkins ◽  
J. W. Dale
Keyword(s):  
Tetracycline Resistance ◽  
Shigella Sonnei ◽  
Conjugative Plasmid ◽  
E Coli ◽  
Low Level ◽  
Variable Level ◽  
High Level ◽  
Level Resistance

SUMMARYThe results presented in this paper confirm the existence of two types of tetracycline resistance inShigella sonnei. One group of strains had a high level of resistance to tetracycline and oxytetracycline, with a variable level of minocycline resistance. The second group had a lower level of tetracycline resistance and were sensitive to minocycline. After conjugation withE. coliK12 the selectedE. colitransconjugants had the same levels of resistance as the parentSh. sonneistrain, with one exception.Sh. sonnei87 was resistant to a high level of tetracycline, but was able to transfer only low level resistance. It is suggested thatSh. sonnei87 carries two plasmids: pSU1, a conjugative plasmid conferring a low level of tetracycline resistance, and pSU2, a non-conjugative plasmid which confers a high level of resistance to tetracycline.

scholarly journals High level resistance to Erythromycin and Tetracycline and dissemination of resistance determinants among clinical enterococci in Kerman-Iran

2021 ◽  
Author(s):  
Nikta Ahmadpoor ◽  
Roya Ahmadrajabi ◽  
Sarvenaz Esfahani ◽  
Zoya Hojabri ◽  
Mohammad Hassan Moshafi ◽  
...  
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Tetracycline Resistance ◽  
Resistance Mechanisms ◽  
Resistance Determinants ◽  
High Prevalence ◽  
Genes Encoding ◽  
High Level ◽  
O 31 ◽  
Level Resistance

Objectives: The purpose of this study was to investigate the distribution pattern of genes responsible for erythromycin and tetracycline resistance and their association with resistance phenotype in enterococci isolates. Materials and Methods: Eighty six Enterococcus faecalis and 26 E. faecium isolates were collected from two hospitals in Kerman-Iran. Minimum inhibitory concentration of erythromycin and tetracycline were determined and then, genes encoding resistance to erythromycin; erm (A-C), mef and msr -and tetracycline; tet (M), tet (O), tet (S), tet (K) and tet (L) – were investigated. Results: In all resistant isolates (n= 72, 64%), high level resistance to both tested antibiotics was found. The most prevalent erm gene was erm (B) (77.7%), followed by erm (A) (15.2%) and erm (C) (8.3%). Genes mediating erythromycin efflux, were detected in 70.8 % (mef) and 9.7% (msr) of resistant isolates. Regarding tetracycline, tet (M) was detected at the highest rate (50%), followed by tet (O) (31%) and tet (S) (11%). Export of tetracycline was found in 31% (tet (K)) and 12% (tet (L)) of isolates. Conclusion: High prevalence of high level resistance to both erythromycin and tetracycline was documented. The alteration at ribosomal level, had bigger role in erythromycin and tetracycline resistance than efflux systems. Concurrent resistance mechanisms were more involved in resistance to erythromycin than tetracycline.

Role of the plasmid-encoded tet(O) gene in tetracycline-resistant clinical isolates of Campylobacter jejuni and Campylobacter coli

2007 ◽  
Vol 56 (6) ◽  
pp. 833-837 ◽  
Author(s):  
Javid Iqbal Dasti ◽  
Uwe Groß ◽  
Sven Pohl ◽  
Raimond Lugert ◽  
Michael Weig ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Campylobacter Jejuni ◽  
Acute Gastroenteritis ◽  
Tetracycline Resistance ◽  
Gene Localization ◽  
Campylobacter Coli ◽  
Low Level ◽  
High Level ◽  
Level Resistance

The prevalence of tetracycline resistance, tetracycline MICs and tet(O) gene localization were investigated in 83 Campylobacter isolates from patients suffering from acute gastroenteritis in Germany. Combined biochemical and molecular markers identified 74 isolates (89 %) as Campylobacter jejuni, including seven atypical isolates that failed to hydrolyse hippurate, and nine isolates (11 %) as Campylobacter coli. Tetracycline resistance was detected in six out of nine Campylobacter coli isolates (67 %) and 13 out of 74 C. jejuni isolates (18 %). Low-level tetracycline resistance was observed for C. coli (MIC 16 μg ml−1 for all strains), whereas C. jejuni showed high-level resistance (MIC >256 μg ml−1 for all strains). Both low- and high-level tetracycline resistance was associated with the presence of the tet(O) gene. In C. jejuni, tet(O) was plasmid-encoded in 54 % of tetracycline-resistant isolates, whereas in C. coli, tet(O) appeared to be located on the chromosome.

scholarly journals WGS of Commensal Neisseria Reveals Acquisition of a New Ribosomal Protection Protein (MsrD) as a Possible Explanation for High Level Azithromycin Resistance in Belgium

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 384
Author(s):  
Tessa de Block ◽  
Jolein Gyonne Elise Laumen ◽  
Christophe Van Dijck ◽  
Said Abdellati ◽  
Irith De Baetselier ◽  
...  
Keyword(s):  
Integration Site ◽  
Bacterial Species ◽  
Resistance Mechanism ◽  
Health Concern ◽  
Sex With Men ◽  
High Level ◽  
Ribosomal Protection Protein ◽  
Commensal Neisseria ◽  
Level Resistance ◽  
Ribosomal Protection

In this study, we characterized all oropharyngeal and anorectal isolates of Neisseria spp. in a cohort of men who have sex with men. This resulted in a panel of pathogenic Neisseria (N. gonorrhoeae [n = 5] and N. meningitidis [n = 5]) and nonpathogenic Neisseria (N. subflava [n = 11], N. mucosa [n = 3] and N. oralis [n = 2]). A high proportion of strains in this panel were resistant to azithromycin (18/26) and ceftriaxone (3/26). Whole genome sequencing (WGS) of these strains identified numerous mutations that are known to confer reduced susceptibility to azithromycin and ceftriaxone in N. gonorrhoeae. The presence or absence of these known mutations did not explain the high level resistance to azithromycin (>256 mg/L) in the nonpathogenic isolates (8/16). After screening for antimicrobial resistance (AMR) genes, we found a ribosomal protection protein, Msr(D), in these highly azithromycin resistant nonpathogenic strains. The complete integration site originated from Streptococcus pneumoniae and is associated with high level resistance to azithromycin in many other bacterial species. This novel AMR resistance mechanism to azithromycin in nonpathogenic Neisseria could be a public health concern if it were to be transmitted to pathogenic Neisseria. This study demonstrates the utility of WGS-based surveillance of nonpathogenic Neisseria.

scholarly journals O05.4 Does high-level azithromycin resistance emerge from low-level resistance inneisseria gonorrhoeae?

2017 ◽  
Author(s):  
Michelle Cole ◽  
Anthony Underwood ◽  
Kate Templeton ◽  
Jill Shepherd ◽  
Gwenda Hughes ◽  
...  
Keyword(s):  
Low Level ◽  
High Level ◽  
Azithromycin Resistance ◽  
Level Resistance

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.

Comparative Study Dynamics of Psychology of Pencak Silat Groups (Iks.Pi Kera Sakti, Persaudaraan Setia Hati Terate, Dan Pagarnusa)

2013 ◽  
Vol 1 (1) ◽  
pp. 114-119
Author(s):  
Imam Muzakky ◽  
Dwi Umi Novitasari ◽  
Siti Hamidah
Keyword(s):  
Comparative Study ◽  
Research Methods ◽  
Martial Arts ◽  
Quantitative Approach ◽  
High Type ◽  
Tolerance Level ◽  
Low Level ◽  
Empirical Paper ◽  
Wide Range ◽  
High Level

Indonesia as a country that offers a wide range of diversity offers its own uniqueness. But unfortunately the diversity it also has the potential for conflict ( Rahardjo , 2010) . Not only the conflict between cultures and groups, as happened in intercollegiate martial arts such as pagarnusa, PSHT and Kerasakti. Objective The purpose of this study to determine the level of aggressiveness, collective pride and tolerance in three martial arts college , this is one of the factors of conflict is high aggressiveness, collective pride and a low level of tolerance. Methodology/Technique The study involved 30 members pagarnusa , 30 members and 30 members kerasakti PSHT . Research methods with quantitative approach. Findings – The findings of this study are a group of college kerasakti have the highest tolerance, low aggression and collective pride being. PSHT has a high level of aggressiveness being and collective tolerance pride being, while the pagarnusa Group aggressiveness levels that are low tolerance level and collective pride high. Findings The findings of this study are a group of college kerasakti have the highest tolerance, low aggression and collective pride being. PSHT has a high level of aggressiveness being and collective tolerance pride being, while the pagarnusa Group aggressiveness levels that are low tolerance level and collective pride high. Type of Paper Empirical paper Keywords: Martial Arts, Aggressiveness, Tolerance , Collective Pride

scholarly journals Antimicrobial Resistance of DiarrheagenicEscherichia coli Isolated from Children under the Age of 5 Years from Ifakara, Tanzania

1999 ◽  
Vol 43 (12) ◽  
pp. 3022-3024 ◽  
Author(s):  
Jordi Vila ◽  
Martha Vargas ◽  
Climent Casals ◽  
Honorato Urassa ◽  
Hassan Mshinda ◽  
...  
Keyword(s):  
Developing Countries ◽  
Public Health Problem ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Important Public Health Problem ◽  
Important Public Health ◽  
E Coli ◽  
High Level ◽  
Level Resistance ◽  
Children Under 5

ABSTRACT Diarrhea caused by multidrug-resistant bacteria is an important public health problem among children in developing countries. The prevalence and antimicrobial susceptibility of diarrheagenicEscherichia coli in 346 children under 5 years of age in Ifakara, Tanzania, were studied. Thirty-eight percent of the cases of diarrhea were due to multiresistant enterotoxigenic E. coli, enteroaggregative E. coli, or enteropathogenicE. coli. Strains of all three E. colicategories showed high-level resistance to ampicillin, tetracycline, co-trimoxazole, and chloramphenicol but were highly susceptible to quinolones. Guidelines for appropriate use of antibiotics in developing countries need updating.

Gamma Spectrometry Systems for the Assay of Uranium Residues and Potentially Contaminated Low Level Wastes at the Capenhurst Site

2003 ◽  
Author(s):  
P. A. Clark ◽  
D. F. Parvin ◽  
C. Y. Powrie ◽  
C. H. Orr ◽  
G. Mottershead ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Matrix Correction ◽  
Uranium Recovery ◽  
Measurement Systems ◽  
Low Level ◽  
Fuel Fabrication ◽  
Wide Range ◽  
Contaminated Waste ◽  
The Uk ◽  
High Level

BNFL has produced and operates a wide range of DrumScan® gamma measurement systems for monitoring packages, drums and boxed wastes arising from nuclear power plant reprocessing, fuel fabrication and decommissioning operations. The challenges associated with decommissioning operations are met by employing a range of technologies predominantly High Resolution and Low Resolution spectrometry (HRGS & LRGS). This paper describes how BNFL Instruments’ LRGS and HRGS DrumScan® gamma measurement systems have been used for the assay of uranium resides and potentially contaminated low level wastes by Capenhurst Integrated Decommissioning Project (IDP) in the UK. A description of the two Capenhurst segmented HRGS systems is included. Whilst Segmented Gamma Scanning is a well established technique for the non-destructive assay of gamma emitting radioisotopes in drummed waste, these systems utlise unique features to address the specific measurement requirements. The first system is configured for the accurate measurement of both small sized containers of uranium residues arising from recovery operations and low level wastes potentially contaminated with uranium contained in 200 litre drums. To achieve a high level of accuracy, this system uses a novel mechanical arrangement to overcome the wide variety of container sizes, and the unique “TransWeight” and “Transmission” matrix correction techniques which provide significant improvements over conventional Segmented Gamma Scanner matrix correction techniques. The second system is configured for Nuclear Safety purposes to provide an upper limit of the 235U present in 200 litre drums of potentially contaminated waste prior to the opening of the drums for sorting and uranium recovery operations. This system is configured to report an appropriately pessimistic upper estimate of the 235U present. A brief description of the LRGS systems used by Capenhurst is also provided. These systems have served to quantify the 235U content within a variety of potentially contaminated waste items ranging from 200 litre drums to 1m3 boxed waste.

scholarly journals Resistance and Virulence Mechanisms of Escherichia coli Selected by Enrofloxacin in Chicken

2019 ◽  
Vol 63 (5) ◽  
Author(s):  
Jun Li ◽  
Haihong Hao ◽  
Menghong Dai ◽  
Heying Zhang ◽  
Jianan Ning ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Efflux Pumps ◽  
Genetic Alterations ◽  
Site Directed Mutagenesis ◽  
Single Mutation ◽  
Genetic Characteristics ◽  
Content Type ◽  
E Coli ◽  
Low Level ◽  
High Level

ABSTRACT This study aimed to investigate the genetic characteristics, antibiotic resistance patterns, and novel mechanisms involved in fluoroquinolone (FQ) resistance in commensal Escherichia coli isolates. The E. coli isolates were recovered from a previous clinical study and subjected to antimicrobial susceptibility testing and molecular typing. Known mechanisms of FQ resistance (target site mutations, plasmid-mediated quinolone resistance [PMQR] genes, relative expression levels of efflux pumps and porins) were detected using DNA sequencing of PCR products and real-time quantitative PCR. Whole-genome shotgun sequencing was performed on 11 representative strains to screen for single nucleotide polymorphisms (SNPs). The function of a key SNP (A1541G) was investigated by site-directed mutagenesis and allelic exchange. The results showed that long-term enrofloxacin treatment selected multidrug-resistant (MDR) E. coli isolates in the chicken gut and that these E. coli isolates had diverse genetic backgrounds. Multiple genetic alterations, including double mutations on GyrA (S83L and D87N), a single mutation on ParC (S80I) and ParE (S458E), activation of efflux pumps, and the presence of the QnrS1 protein, contributed to the high-level FQ resistance (enrofloxacin MIC [MICENR] ≥ 128 μg/ml), while the relatively low-level FQ resistance (MICENR = 8 or 16 μg/ml) was commonly mediated by decreased expression of the porin OmpF, besides enhancement of the efflux pumps. No significant relationship was observed between resistance mechanisms and virulence genes. Introduction of the A1541G mutation on aegA was able to increase FQ susceptibility by 2-fold. This study contributes to a better understanding of the development of MDR and the differences underlying the mechanisms of high-level and low-level FQ resistance in E. coli.

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