scholarly journals Transformation of fluoroquinolone-resistance Neisseria gonorrhoeae gyrA and parC genes

2020 ◽  
pp. 55-63
Author(s):  
Szymon Walter de Walthoffen
Keyword(s):  
Amino Acid ◽  
Resistance Mechanisms ◽  
Fluoroquinolone Resistance ◽  
Gyra Gene ◽  
Gene Encoding ◽  
Double Mutation ◽  
Sexually Transmitted ◽  
Acid Acid ◽  
Causative Agents ◽  
Sensitive Isolate

Introduction: N. gonorrhoeae is one of the etiological causative agents of one of the most common sexually transmitted diseases. Gonococci has created many resistance mechanisms, which is associated with bacterial evolution. Natural transformation is the basic method of horizontal gene transfer in bacteria of the genus Neisseria, which can lead to a mutation in the gyrA gene encoding DNA gyrase. The aim of the study was to verify the view on the significance of mutations at positions 91 and 95 of the gyrA protein on the sensitivity of N. gonorrhoeae to antibiotics of the quinolone type. Methods: GyrA gene was introduced into an sensitive isolate of N. gonorrhoeae using genetic transformation. Resistance gene donor, recipient and transform strains were tested for susceptibility and the gyrA gene was sequenced. Results: It has been shown that double mutation in amino acid acid sequence of the GyrA protein at positions 91 and 95 increase the value of MIC from 0,003 mg / L to 0,125 mg / L at CIP sensitive N. gonorrhoeae strain. Conclusions: Mutations in the amino acid sequence at positions 91 and 95 affet the strain’s sensitivity to ciprofloxacin, but it is not the only mechanism which could alter the MIC value of quinolones.

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 Novel mutations in the QRDR region gyrA gene in multidrug-resistance Corynebacterium spp. isolates from intravenous sites

2019 ◽  
Vol 113 (4) ◽  
pp. 589-592 ◽  
Author(s):  
Juliana Nunes Ramos ◽  
Talita Bernardo Valadão ◽  
Paulo Victor Pereira Baio ◽  
Ana Luiza Mattos-Guaraldi ◽  
Verônica Viana Vieira
Keyword(s):  
Multidrug Resistant ◽  
Gyra Gene ◽  
Gene Encoding ◽  
Double Mutation ◽  
Wide Range ◽  
Corynebacterium Striatum ◽  
Invasive Infections ◽  
Gyrase A ◽  
A Subunit ◽  
Corynebacterium Urealyticum

AbstractThe resistance to fluoroquinolones in corynebacteria is due to mutations occurring in the quinolone-resistance-determining region (QRDR) of the gyrA gene encoding the enzyme gyrase A subunit. In recent years we can observe an increasing number of infections caused by multidrug-resistant Corynebacterium striatum, Corynebacterium jeikeium and Corynebacterium urealyticum, including wide range of disorders, such as invasive infections. In this study 14 Corynebacterium spp. isolated from intravenous sites were sequenced and new combinations of mutations in the QRDR of the gyrA gene were found in C. jeikeium and C. urealyticum. Nowadays, no study comparing mutations in this region and the susceptibility to fluoroquinolones in C. jeikeium and C. urealyticum has been described. All the isolates that showed double mutation (position 87 and 91) in the QRDR gyrA gene had high MIC to the fluoroquinolones tested.

scholarly journals Mutations in Topoisomerase IV and DNA Gyrase of Staphylococcus aureus: Novel Pleiotropic Effects on Quinolone and Coumarin Activity

1998 ◽  
Vol 42 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Bénédicte Fournier ◽  
David C. Hooper
Keyword(s):  
Staphylococcus Aureus ◽  
Dna Gyrase ◽  
Single Step ◽  
Pleiotropic Effects ◽  
Fluoroquinolone Resistance ◽  
Wild Type ◽  
Chromosomal Dna ◽  
Topoisomerase Iv ◽  
Gene Encoding ◽  
Double Mutation

ABSTRACT Previous studies have shown that topoisomerase IV and DNA gyrase interact with quinolones and coumarins in different ways. The MICs of coumarins (novobiocin and coumermycin) for MT5, a Staphylococcus aureus nov mutant, are higher than those for wild-type strains. Sequencing the gyrB gene encoding one subunit of the DNA gyrase revealed the presence of a double mutation likely to be responsible for this resistance: at codon 102 (Ile to Ser) and at codon 144 (Arg to Ile). For single-step flqA mutant MT5224c9, previously selected on ciprofloxacin, the fluoroquinolone MIC was higher and the coumarin MIC was lower than those for its parent, MT5. Sequencing the grlB andgrlA genes of topoisomerase IV of MT5224c9 showed a single Asn-470-to-Asp mutation in GrlB. Genetic outcrosses by transformation with chromosomal DNA and introduction of plasmids carrying either the wild-type or the mutated grlB gene indicated that this mutation causes both increased MICs of fluoroquinolones and decreased MICs of coumarins and that the mutant grlBallele is codominant for both phenotypes with multicopy alleles. Integration of these plasmids into the chromosome confirmed the codominance of fluoroquinolone resistance, butgrlB + appeared dominant over grlB(Asp-470) for coumarin resistance. Finally, the gyrA(Leu-84) mutation previously described as silent for fluoroquinolone resistance increased the MIC of nalidixic acid, a nonfluorinated quinolone. Combining the grlA (Phe-80) and grlB(Asp-470) mutations with this gyrA mutation also had differing effects. The findings indicate that alterations in topoisomerases may have pleiotropic effects on different classes of inhibitors as well as on inhibitors within the same class. A full understanding of drug action and resistance at the molecular level must take into account both inhibitor structure-activity relationships and the effects of different classes of topoisomerase mutants.

scholarly journals Identification of 14-α-Lanosterol Demethylase (CYP51) in Scedosporium Species

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Anne Bernhardt ◽  
Wieland Meyer ◽  
Volker Rickerts ◽  
Toni Aebischer ◽  
Kathrin Tintelnot
Keyword(s):  
Amino Acid ◽  
Resistance Mechanisms ◽  
Upstream Region ◽  
Scedosporium Apiospermum ◽  
Gene Encoding ◽  
Specific Amino Acid ◽  
Content Type ◽  
Scedosporium Dehoogii ◽  
Lanosterol Demethylase ◽  
Species Specific

ABSTRACT Scedosporium spp. cause infections (scedosporiosis) in both immunocompetent and immunocompromised individuals and may persistently colonize the respiratory tract in patients with cystic fibrosis (CF). They are less susceptible against azoles than are other molds, such as Aspergillus spp., suggesting the presence of resistance mechanisms. It can be hypothesized that the decreased susceptibility of Scedosporium spp. to azoles is also CYP51 dependent. Analysis of the Scedosporium apiospermum and Scedosporium aurantiacum genomes revealed one CYP51 gene encoding the 14-α-lanosterol demethylase. This gene from 159 clinical or environmental Scedosporium isolates and three Lomentospora prolificans isolates has been sequenced and analyzed. The Scedosporium CYP51 protein clustered with the group of known CYP51B orthologues and showed species-specific polymorphisms. A tandem repeat in the 5′ upstream region of Scedosporium CYP51 like that in Aspergillus fumigatus could not be detected. Species-specific amino acid alterations in CYP51 of Scedosporium boydii, Scedosporium ellipsoideum, Scedosporium dehoogii, and Scedosporium minutisporum isolates were located at positions that have not been described as having an impact on azole susceptibility. In contrast, two of the three S. apiospermum-specific amino acid changes (Y136F and G464S) corresponded to respective mutations in A. fumigatus CYP51A at amino acid positions 121 and 448 (Y121F and G448S, respectively) that had been linked to azole resistance.

Molecular Characterization of Fluoroquinolone Resistance Mechanisms of Campylobacter Isolates from Duck Meats

2017 ◽  
Vol 80 (12) ◽  
pp. 2056-2059
Author(s):  
Min Kang ◽  
Bai Wei ◽  
Sung-Woon Choi ◽  
Se-Yeoun Cha ◽  
Hyung-Kwan Jang
Keyword(s):  
Nalidixic Acid ◽  
Efflux Pump ◽  
Resistance Mechanisms ◽  
Quinolone Resistance ◽  
Fluoroquinolone Resistance ◽  
Gyra Gene ◽  
Meat Samples ◽  
High Level ◽  
Level Resistance

ABSTRACT The purpose of this study was to identify the molecular basis of quinolone resistance of Campylobacter isolates recovered from duck meats. Sixty-one isolates from duck meat samples were studied using sequence analysis of the gyrA gene, and PCR assays were used to identify the presence of the CmeABC efflux pump and its restored sensitivity in the presence of efflux-pump inhibitors. High-level resistance to nalidixic acid and ciprofloxacin was attributed to amino acid substitutions Thr-86-Ile in some isolates. The PCR assay confirmed the presence of the cmeB gene in 29 (47.5%) of the 61 Campylobacter isolates. Phenylalanine arginine β-naphthylamide reduced the MICs of ciprofloxacin and nalidixic acid in 16 (55.2%) and 26 (89.7%) isolates, respectively. The Thr-86-Ile substitution in the gyrA was the primary contributor to the high-level quinolone resistance in Campylobacter isolates from duck meats.

scholarly journals Ampicillin-Resistant Non-β-Lactamase-Producing Haemophilus influenzae in Spain: Recent Emergence of Clonal Isolates with Increased Resistance to Cefotaxime and Cefixime

2007 ◽  
Vol 51 (7) ◽  
pp. 2564-2573 ◽  
Author(s):  
Silvia García-Cobos ◽  
José Campos ◽  
Edurne Lázaro ◽  
Federico Román ◽  
Emilia Cercenado ◽  
...  
Keyword(s):  
Amino Acid ◽  
Haemophilus Influenzae ◽  
Efflux Pump ◽  
Antibiotic Use ◽  
Resistance Mechanisms ◽  
Amino Acid Substitutions ◽  
Gene Encoding ◽  
Reading Frame ◽  
Recent Emergence ◽  
Acrab Efflux Pump

ABSTRACT The sequence of the ftsI gene encoding the transpeptidase domain of penicillin-binding protein 3 (PBP 3) was determined for 354 nonconsecutive Haemophilus influenzae isolates from Spain; 17.8% of them were ampicillin susceptible, 56% were β-lactamase nonproducing ampicillin resistant (BLNAR), 15.8% were β-lactamase producers and ampicillin resistant, and 10.4% displayed both resistance mechanisms. The ftsI gene sequences had 28 different mutation patterns and amino acid substitutions at 23 positions. Some 93.2% of the BLNAR strains had amino acid substitutions at the Lys-Thr-Gly (KTG) motif, the two most common being Asn526 to Lys (83.9%) and Arg517 to His (9.3%). Amino acid substitutions at positions 377, 385, and 389, which conferred cefotaxime and cefixime MICs 10 to 60 times higher than those of susceptible strains, were found for the first time in Europe. In 72 isolates for which the repressor acrR gene of the AcrAB efflux pump was sequenced, numerous amino acid substitutions were found. Eight isolates with ampicillin MICs of 0.25 to 2 μg/ml showed changes that predicted the early termination of the acrR reading frame. Pulsed-field gel electrophoresis analysis demonstrated that most BLNAR strains were genetically diverse, although clonal dissemination was detected in a group of isolates presenting with increased resistance to cefotaxime and cefixime. Background antibiotic use at the community level revealed a marked trend toward increased amoxicillin-clavulanic acid consumption. BLNAR H. influenzae strains have arisen by vertical and horizontal spread and have evolved to adapt rapidly to the increased selective pressures posed by the use of oral penicillins and cephalosporins.

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 Constitutive SoxS Expression in a Fluoroquinolone-Resistant Strain with a Truncated SoxR Protein and Identification of a New Member of the marA-soxS-rob Regulon, mdtG

2009 ◽  
Vol 54 (3) ◽  
pp. 1218-1225 ◽  
Author(s):  
Anna Fàbrega ◽  
Robert G. Martin ◽  
Judah L. Rosner ◽  
M. Mar Tavio ◽  
Jordi Vila
Keyword(s):  
Antibiotic Resistance ◽  
Amino Acid ◽  
Resistant Strain ◽  
Efflux Pump ◽  
Transcriptional Activator ◽  
Resistance Mechanisms ◽  
Fluoroquinolone Resistance ◽  
Reverse Transcription Pcr ◽  
Chromosomal Mutations

ABSTRACT Elevated levels of fluoroquinolone resistance are frequently found among Escherichia coli clinical isolates. This study investigated the antibiotic resistance mechanisms of strain NorE5, derived in vitro by exposing an E. coli clinical isolate, PS5, to two selection steps with increasing concentrations of norfloxacin. In addition to the amino acid substitution in GyrA (S83L) present in PS5, NorE5 has an amino acid change in ParC (S80R). Furthermore, we now find by Western blotting that NorE5 has a multidrug resistance phenotype resulting from the overexpression of the antibiotic resistance efflux pump AcrAB-TolC. Microarray and gene fusion analyses revealed significantly increased expression in NorE5 of soxS, a transcriptional activator of acrAB and tolC. The high soxS activity is attributable to a frameshift mutation that truncates SoxR, rendering it a constitutive transcriptional activator of soxS. Furthermore, microarray and reverse transcription-PCR analyses showed that mdtG (yceE), encoding a putative efflux pump, is overexpressed in the resistant strain. SoxS, MarA, and Rob activated an mdtG::lacZ fusion, and SoxS was shown to bind to the mdtG promoter, showing that mdtG is a member of the marA-soxS-rob regulon. The mdtG marbox sequence is in the backward or class I orientation within the promoter, and its disruption resulted in a loss of inducibility by MarA, SoxS, and Rob. Thus, chromosomal mutations in parC and soxR are responsible for the increased antibiotic resistance of NorE5.

Cationic Antimicrobial Peptides for Tuberculosis: A Mini-Review

2019 ◽  
Vol 20 (9) ◽  
pp. 885-892
Author(s):  
Sara Silva ◽  
Nuno Vale
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Amino Acid ◽  
Antimicrobial Peptides ◽  
Resistance Mechanisms ◽  
Therapeutic Agents ◽  
Pharmacological Properties ◽  
Therapeutic Activity ◽  
Alternative Strategies ◽  
Cationic Antimicrobial Peptides ◽  
Specific Amino Acid

Cationic antimicrobial peptides (CAMPs) can be considered as new potential therapeutic agents for Tuberculosis treatment with a specific amino acid sequence. New studies can be developed in the future to improve the pharmacological properties of CAMPs and also understand possible resistance mechanisms. This review discusses the principal properties of natural and/or synthetic CAMPs, and how these new peptides have a significant specificity for Mycobacterium tuberculosis. Also, we propose some alternative strategies to enhance the therapeutic activity of these CAMPs that include coadministration with nanoparticles and/or classic drugs.

Identification of the gene encoding 3-(5-oxo-2-thioxoimidazolidin-4-yl) propionic acid desulfhydrase in Burkholderia sp. HME13

2020 ◽  
Vol 85 (3) ◽  
pp. 626-629
Author(s):  
Hisashi Muramatsu ◽  
Hiroki Maguchi ◽  
Taisuke Harada ◽  
Takehiro Kashiwagi ◽  
Chul-Sa Kim ◽  
...  
Keyword(s):  
Amino Acid ◽  
Sequence Analysis ◽  
Amino Acid Sequence ◽  
Propionic Acid ◽  
Unknown Function ◽  
Protein Family ◽  
Amino Acid Sequence Analysis ◽  
Gene Encoding

ABSTRACT Here, we report the identification of the gene encoding a novel enzyme, 3-(5-oxo-2-thioxoimidazolidin-4-yl) propionic acid desulfhydrase, in Burkholderia sp. HME13. The enzyme converts 3-(5-oxo-2-thioxoimidazolidin-4-yl) propionic acid and H2O to 3-(2,5-dioxoimidazolidin-4-yl) propionic acid and H2S. Amino acid sequence analysis of the enzyme indicates that it belongs to the DUF917 protein family, which consists of proteins of unknown function.

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