scholarly journals Molecular Study of Quinolone Resistance Determining Regions of gyrA Gene and parC Genes in Clinical Isolates of Acintobacter baumannii Resistant to Fluoroquinolone

2018 ◽  
Vol 12 (1) ◽  
pp. 116-122
Author(s):  
Maysaa El Sayed Zaki ◽  
Nermen Abou ElKheir ◽  
Mohamed Mofreh
Keyword(s):  
Large Scale ◽  
Molecular Mechanisms ◽  
Molecular Study ◽  
Quinolone Resistance ◽  
Clinical Isolates ◽  
Resistance Pattern ◽  
Single Mutation ◽  
Gyra Gene ◽  
Frequent Mutations ◽  
Dilution Tube

Introduction: Acinetobacterb aumannii (A. baumannii) is an important pathogen in health care associated infections. Quinolone resistance has emerged in this pathogen. Aims & Objectives: The aim of the present study was to determine the presence of mutations of gyrA gene and parC genes by Restriction Fragment Length Polymorphism Polymerase Chain Reaction (RFLP-PCR) among clinical isolates of A. baumanii. Materials and Methods: The study was carried out on 140 clinical isolates of A. baumannii. The isolates were subjected to molecular study of mutations of gyrA gene and parC genes by RFLP–PCR beside determination of Minimal Inhibitory Concentration (MIC) by macro dilution tube method. Results: The isolates of A. baumannii were resistant to ciprofloxacine and levofloxacin at MIC >4 µg/ml. The most isolates had MIC >128 µg/ml (42.3%). All resistant strains to ciprofloxacin of A. baumannii had mutations in gyrA and parC. The most frequent mutations were combined mutations in both genes (85.5%) and 5% had single mutation either in gyrA or parC. The most frequently combined mutations were associated with MIC >128 µg/ml (42.3%). Conclusion: From this study we can conclude that resistance to ciprofloxacin was common in clinical isolates of A. baumannii. The most frequent mutations were present in gyrA and parC. However, mutations in parC alone were not uncommon. Further large scale studies are required to elucidate the resistance pattern of A. baumannii and its molecular mechanisms.

scholarly journals Relationship between Mutations in the gyrA Gene and Quinolone Resistance in Clinical Isolates of Corynebacterium striatum and Corynebacterium amycolatum

2005 ◽  
Vol 49 (5) ◽  
pp. 1714-1719 ◽  
Author(s):  
Josep M. Sierra ◽  
Luis Martinez-Martinez ◽  
Fernando Vázquez ◽  
Ernest Giralt ◽  
Jordi Vila
Keyword(s):  
Amino Acid ◽  
Test Method ◽  
Quinolone Resistance ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Moderate Increase ◽  
Gyra Gene ◽  
Double Mutation ◽  
Corynebacterium Striatum

ABSTRACT Quinolone susceptibility was analyzed in 17 clinical isolates of Corynebacterium striatum and 9 strains of Corynebacterium amycolatum by the E-test method in Mueller-Hinton agar plates. The C. striatum ATCC 6940 strain was used as a control strain. The amplified quinolone resistance determining regions of the gyrA genes of C. amycolatum and C. striatum were characterized. Four in vitro quinolone-resistant mutants of C. amycolatum were selected and analyzed. Both in vivo and in vitro quinolone-resistant strains of C. amycolatum showed high levels of fluoroquinolone resistance in strains with a double mutation leading to an amino acid change in positions 87 and 91 or positions 87 and 88 (unusual mutation) of GyrA, whereas the same concomitant mutations at amino acid positions 87 and 91 in GyrA of C. striatum produced high levels of resistance to ciprofloxacin and levofloxacin but only showed a moderate increase in the MIC of moxifloxacin, suggesting that other mechanism(s) of quinolone resistance could be involved in moxifloxacin resistance in C. amycolatum. Moreover, a PCR-RFLP-NcoI of the gyrA gene was developed to distinguish between C. amycolatum and C. striatum species.

scholarly journals The evolution of drug resistance in clinical isolates of Candida albicans

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Christopher B Ford ◽  
Jason M Funt ◽  
Darren Abbey ◽  
Luca Issi ◽  
Candace Guiducci ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Candida Albicans ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Oral Candidiasis ◽  
Host Adaptation ◽  
Copy Number Variations ◽  
Clinical Isolates ◽  
Ergosterol Biosynthesis ◽  
Healthy Human

Candida albicans is both a member of the healthy human microbiome and a major pathogen in immunocompromised individuals. Infections are typically treated with azole inhibitors of ergosterol biosynthesis often leading to drug resistance. Studies in clinical isolates have implicated multiple mechanisms in resistance, but have focused on large-scale aberrations or candidate genes, and do not comprehensively chart the genetic basis of adaptation. Here, we leveraged next-generation sequencing to analyze 43 isolates from 11 oral candidiasis patients. We detected newly selected mutations, including single-nucleotide polymorphisms (SNPs), copy-number variations and loss-of-heterozygosity (LOH) events. LOH events were commonly associated with acquired resistance, and SNPs in 240 genes may be related to host adaptation. Conversely, most aneuploidies were transient and did not correlate with drug resistance. Our analysis also shows that isolates also varied in adherence, filamentation, and virulence. Our work reveals new molecular mechanisms underlying the evolution of drug resistance and host adaptation.

scholarly journals PremPS: Predicting the impact of missense mutations on protein stability

2020 ◽  
Vol 16 (12) ◽  
pp. e1008543
Author(s):  
Yuting Chen ◽  
Haoyu Lu ◽  
Ning Zhang ◽  
Zefeng Zhu ◽  
Shuqin Wang ◽  
...  
Keyword(s):  
Protein Stability ◽  
Protein Design ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Predictive Performance ◽  
Computational Method ◽  
Single Mutation ◽  
Missense Mutations ◽  
Benchmark Datasets ◽  
The Impact

Computational methods that predict protein stability changes induced by missense mutations have made a lot of progress over the past decades. Most of the available methods however have very limited accuracy in predicting stabilizing mutations because existing experimental sets are dominated by mutations reducing protein stability. Moreover, few approaches could consistently perform well across different test cases. To address these issues, we developed a new computational method PremPS to more accurately evaluate the effects of missense mutations on protein stability. The PremPS method is composed of only ten evolutionary- and structure-based features and parameterized on a balanced dataset with an equal number of stabilizing and destabilizing mutations. A comprehensive comparison of the predictive performance of PremPS with other available methods on nine benchmark datasets confirms that our approach consistently outperforms other methods and shows considerable improvement in estimating the impacts of stabilizing mutations. A protein could have multiple structures available, and if another structure of the same protein is used, the predicted change in stability for structure-based methods might be different. Thus, we further estimated the impact of using different structures on prediction accuracy, and demonstrate that our method performs well across different types of structures except for low-resolution structures and models built based on templates with low sequence identity. PremPS can be used for finding functionally important variants, revealing the molecular mechanisms of functional influences and protein design. PremPS is freely available at https://lilab.jysw.suda.edu.cn/research/PremPS/, which allows to do large-scale mutational scanning and takes about four minutes to perform calculations for a single mutation per protein with ~ 300 residues and requires ~ 0.4 seconds for each additional mutation.

scholarly journals Alterations in the GyrA subunit of DNA gyrase and the ParC subunit of topoisomerase IV in quinolone-resistant clinical isolates of Klebsiella pneumoniae.

1997 ◽  
Vol 41 (3) ◽  
pp. 699-701 ◽  
Author(s):  
T Deguchi ◽  
A Fukuoka ◽  
M Yasuda ◽  
M Nakano ◽  
S Ozeki ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Dna Gyrase ◽  
Quinolone Resistance ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Primary Target ◽  
Gyra Gene ◽  
Topoisomerase Iv ◽  
Complementary Role

We determined a partial sequence of the Klebsiella pneumoniae parC gene, including the region analogous to the quinolone resistance-determining region of the Escherichia coli gyrA gene, and examined 26 clinical strains of K. pneumoniae for an association of alterations in GyrA and ParC with susceptibilities to quinolones. The study suggests that in K. pneumoniae DNA gyrase is a primary target of quinolones and that ParC alterations play a complementary role in the development of higher-level fluoroquinolone resistance.

Molecular study of quinolone resistance mechanisms and clonal relationship of Salmonella enterica clinical isolates

2014 ◽  
Vol 43 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Clara Ballesté-Delpierre ◽  
Mar Solé ◽  
Òscar Domènech ◽  
Jordi Borrell ◽  
Jordi Vila ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Molecular Study ◽  
Resistance Mechanisms ◽  
Quinolone Resistance ◽  
Clinical Isolates ◽  
Clonal Relationship ◽  
Relationship Of

scholarly journals Cloning and Nucleotide Sequence of the DNA Gyrase gyrA Gene from Serratia marcescens and Characterization of Mutations in gyrA of Quinolone-Resistant Clinical Isolates

1998 ◽  
Vol 42 (1) ◽  
pp. 190-193 ◽  
Author(s):  
Jeong Hoon Kim ◽  
Eun Hee Cho ◽  
Kwang Seo Kim ◽  
Hak Yeop Kim ◽  
Young Min Kim
Keyword(s):  
Serratia Marcescens ◽  
Dna Gyrase ◽  
Quinolone Resistance ◽  
Clinical Isolates ◽  
Single Amino Acid ◽  
Common Mechanism ◽  
Temperature Sensitive ◽  
Gyra Gene ◽  
Calculated Molecular Mass ◽  
Reading Frame

ABSTRACT The sequence of the DNA gyrase gyrA gene ofSerratia marcescens ATCC 14756 was determined. An open reading frame of 2,640 nucleotides coding for a polypeptide with a calculated molecular mass of 97,460 was found, and its sequence complemented the sequence of an Escherichia coli gyrAtemperature-sensitive mutation. Analysis of the PCR products of the quinolone resistance-determining regions of gyrA genes from six quinolone-resistant clinical isolates revealed a single amino acid substitution, Ser-83 to Arg or Asp-87 to Tyr, in all six mutants, suggesting that a mutational alteration in gyrA is a common mechanism of quinolone resistance in S. marcescens.

scholarly journals Bacteriological and Molecular Study of Fluoroquinolones Resistance in Pseudomonas aeruginosa Isolated From Different Clinical Sources

2020 ◽  
pp. 2204-2214
Author(s):  
Mustafa Abd Al-Mayali ◽  
Ehab D. Salman
Keyword(s):  
Basic Mechanism ◽  
Molecular Study ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Rrna Gene ◽  
Direct Sequence ◽  
Gyra Gene ◽  
Gene Encoding ◽  
Sequence Method ◽  
Different Sources

The present study was conducted to investigate the resistance of fluoroquinolones (FQs) and the effects of mutations in the resistance gene in clinical isolates of P. aeruginosa isolated from different sources in Al-Hussein Hospital, Al-Samawah city, Iraq. The basic mechanism of the resistant of fluoroquinolones in P. aeruginosa is via mutations occurring in the basic bacterial gyrA gene encoding-subunit A of DNA gyrase . Forty clinical isolates from various sourced  (burn 7 (17.5 %), wound 7 (17.5 %), ear 2 (5 %), operation room 12 (30 %), urine 3 (7.5 %), and industrial dialysis center 9 (22.5 %)) were isolated based on bacteriological methods confirmed by 16s rRNA gene using PCR technique. A sensitivity test was conducted to all isolates by Kirby-Pour method using 7 antibiotics of fluoroquinolones. Amongst the 40 clinical isolates, 10 were resistant and 3 were sensitive to all tested antibiotics, while 27 were intermediate, resistant and sensitive to two or more of tested antibiotics, with the resistance being confirmed by the minimum inhibitor concentration (MIC) test. The ten resistant isolates were used to examine the mutations in gyrA gene. A direct sequence method was used and revealed eight mutations in gyrA gene at different positions. In addition, we found that fluoroquinolone activity in the sensitive isolates, after sequencing for these isolates, is a bacteriostatic activity. The results of this study showed the gyrA mutations resulting from the excessive use of antibiotics are one of the mechanisms may be that leading to fluoroquinolone resistance.

scholarly journals EGCG binds intrinsically disordered N-terminal domain of p53 and disrupts p53-MDM2 interaction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Zhao ◽  
Alan Blayney ◽  
Xiaorong Liu ◽  
Lauren Gandy ◽  
Weihua Jin ◽  
...  
Keyword(s):  
Large Scale ◽  
Molecular Mechanisms ◽  
Epigallocatechin Gallate ◽  
Cancer Drug ◽  
Dynamic Interactions ◽  
Cancer Drug Discovery ◽  
Intrinsically Disordered ◽  
Terminal Domain ◽  
Cancerous Cells

AbstractEpigallocatechin gallate (EGCG) from green tea can induce apoptosis in cancerous cells, but the underlying molecular mechanisms remain poorly understood. Using SPR and NMR, here we report a direct, μM interaction between EGCG and the tumor suppressor p53 (KD = 1.6 ± 1.4 μM), with the disordered N-terminal domain (NTD) identified as the major binding site (KD = 4 ± 2 μM). Large scale atomistic simulations (>100 μs), SAXS and AUC demonstrate that EGCG-NTD interaction is dynamic and EGCG causes the emergence of a subpopulation of compact bound conformations. The EGCG-p53 interaction disrupts p53 interaction with its regulatory E3 ligase MDM2 and inhibits ubiquitination of p53 by MDM2 in an in vitro ubiquitination assay, likely stabilizing p53 for anti-tumor activity. Our work provides insights into the mechanisms for EGCG’s anticancer activity and identifies p53 NTD as a target for cancer drug discovery through dynamic interactions with small molecules.

Sign in / Sign up

Export Citation Format

Share Document