First Characterization of Fluoroquinolone Resistance in Streptococcus suis

ABSTRACT We have identified and sequenced the genes encoding the quinolone-resistance determining region (QRDR) of ParC and GyrA in fluoroquinolone-susceptible and -resistant Streptococcus suis clinical isolates. Resistance is the consequence of single point mutations in the QRDRs of ParC and GyrA and is not due to clonal spread of resistant strains or horizontal gene transfer with other bacteria.

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Molecular Basis of Resistance to Selected Antimicrobial Agents in the Emerging Zoonotic Pathogen Streptococcus suis

Journal of Clinical Microbiology ◽

10.1128/jcm.00123-15 ◽

2015 ◽

Vol 53 (7) ◽

pp. 2332-2336 ◽

Cited By ~ 21

Author(s):

Mamata Gurung ◽

Migma Dorji Tamang ◽

Dong Chan Moon ◽

Su-Ran Kim ◽

Jin-Ha Jeong ◽

...

Keyword(s):

Molecular Basis ◽

Antimicrobial Agents ◽

Single Point ◽

Point Mutations ◽

Streptococcus Suis ◽

Quinolone Resistance ◽

Content Type ◽

Zoonotic Pathogen ◽

Single Point Mutations

Characterization of 227Streptococcus suisstrains isolated from pigs during 2010 to 2013 showed high levels of resistance to clindamycin (95.6%), tilmicosin (94.7%), tylosin (93.8%), oxytetracycline (89.4%), chlortetracycline (86.8%), tiamulin (72.7%), neomycin (70.0%), enrofloxacin (56.4%), penicillin (56.4%), ceftiofur (55.9%), and gentamicin (55.1%). Resistance to tetracyclines, macrolides, aminoglycosides, and fluoroquinolone was attributed to thetetgene,erm(B),erm(C),mph(C), andmef(A) and/ormef(E) genes,aph(3′)-IIIaandaac(6′)-Ie-aph(2″)-Iagenes, and single point mutations in the quinolone resistance-determining region of ParC and GyrA, respectively.

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PCR and Cancer Diagnostics: Detection and Characterization of Single Point Mutations in Oncogenes and Antioncogenes

The Polymerase Chain Reaction ◽

10.1007/978-1-4612-0257-8_31 ◽

1994 ◽

pp. 369-394 ◽

Cited By ~ 2

Author(s):

Manuel Perucho

Keyword(s):

Single Point ◽

Point Mutations ◽

Cancer Diagnostics ◽

Single Point Mutations

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HIV recombination: what is the impact on antiretroviral therapy?

Journal of The Royal Society Interface ◽

10.1098/rsif.2005.0064 ◽

2005 ◽

Vol 2 (5) ◽

pp. 489-503 ◽

Cited By ~ 50

Author(s):

Christophe Fraser

Keyword(s):

Antiretroviral Therapy ◽

Single Point ◽

Point Mutations ◽

Wild Type Virus ◽

Wild Type ◽

Genetic Barrier ◽

Resistant Strains ◽

Single Point Mutations ◽

The Impact ◽

Retroviral Recombination

Retroviral recombination is a potential mechanism for the development of multiply drug resistant viral strains but the impact on the clinical outcomes of antiretroviral therapy in HIV-infected patients is unclear. Recombination can favour resistance by combining single-point mutations into a multiply resistant genome but can also hinder resistance by breaking up associations between mutations. Previous analyses, based on population genetic models, have suggested that whether recombination is favoured or hindered depends on the fitness interactions between loci, or epistasis. In this paper, a mathematical model is developed that includes viral dynamics during therapy and shows that population dynamics interact non-trivially with population genetics. The outcome of therapy depends critically on the changes to the frequency of cell co-infection and I review the evidence available. Where recombination does have an effect on therapy, it is always to slow or even halt the emergence of multiply resistant strains. I also find that for patients newly infected with multiply resistant strains, recombination can act to prevent reversion to wild-type virus. The analysis suggests that treatment targeted at multiple parts of the viral life-cycle may be less prone to drug resistance due to the genetic barrier caused by recombination but that, once selected, mutants resistant to such regimens may be better able to persist in the population.

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Epidemic and molecular characterization of fluoroquinolone-resistant Shigella dysenteriae 1 isolates from calves with diarrhea

10.21203/rs.3.rs-32990/v1 ◽

2020 ◽

Author(s):

Zhen Zhu ◽

Mingze Cao ◽

Weiwei Wang ◽

Liwei Zhang ◽

Guanhui Liu ◽

...

Keyword(s):

Molecular Characterization ◽

Virulence Genes ◽

Point Mutations ◽

Multidrug Resistant ◽

Gansu Province ◽

Shigella Dysenteriae ◽

Fluoroquinolone Resistance ◽

Resistant Strains ◽

And Control

Abstract Background: The widespread distribution of antimicrobial-resistant Shigella has become a recurrent challenge in many parts of the developing world. Previous studies indicate that the host of Shigella has expanded from humans to animals. This study aimed to investigate the prevalence of fluoroquinolone resistance and associated molecular characterization of S. dysenteriae 1 isolated from calves. Methods and Results: All 38 unduplicated S. dysenteriae 1 isolates were collected from calves in Gansu Province from October 2014 to December 2016. According to MLST and PFGE analysis, these isolates were separated into 4 and 28 genotypes, respectively. The most common STs identified were ST228 (34.21%, 13/38) and ST229 (39.47%, 15/38), which were first found in the present study. All isolates harbored virulence genes, and the incidence of the five virulence genes were ipaH (100%), ipaBCD (92.11%), stx (73.68%), ial (57.89%), and sen (28.95%). According to the results of antimicrobial susceptibilities, 76.32% (29/38) of S. dysenteriae isolates were resistant to fluoroquinolone and showed multidrug resistance. In a study on the polymorphism of QRDR of gyrA/B and parC/E genes, we identified two mutations in gyrA (Ser83→Leu and Asp87→Asn) and parC (Ser80→Ile and Ser83→Leu), respectively. Among them, 55.17% (16/29) of resistant strains had the gyrA point mutations (Ser83→Leu) and parC point mutation (Ser83→Leu). Moreover, 41.38% (12/29) of isolates had all five point mutations of gyrA and parC. In addition, the prevalence of the PMQR determinant genes was also investigated. All 29 fluoroquinolone-resistant isolates were positive for the aac(6’)-Ib-cr gene but negative for qepA, except SD001. In addition, only 6 (20.69%, 6/29) isolates harbored the qnr gene, including two with qnrB (6.90%, 2/29) and four with qnrS (13.79%, 4/29). Conclusion: Given the increased common emergence of multidrug resistant isolates, uninterrupted surveillance will be necessary to understand the actual epidemic burden and control this infection.

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Characterization of a Lineage C.36 SARS-CoV-2 Isolate with Reduced Susceptibility to Neutralization Circulating in Lombardy, Italy

Viruses ◽

10.3390/v13081514 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1514

Author(s):

Matteo Castelli ◽

Andreina Baj ◽

Elena Criscuolo ◽

Roberto Ferrarese ◽

Roberta A. Diotti ◽

...

Keyword(s):

Molecular Characterization ◽

Single Point ◽

Point Mutations ◽

Humoral Response ◽

Genomic Sequencing ◽

Single Point Mutations

SARS-CoV-2 spike is evolving to maximize transmissibility and evade the humoral response. The massive genomic sequencing of SARS-CoV-2 isolates has led to the identification of single-point mutations and deletions, often having the recurrence of hotspots, associated with advantageous phenotypes. We report the isolation and molecular characterization of a SARS-CoV-2 strain, belonging to a lineage (C.36) not previously associated with concerning traits, which shows decreased susceptibility to vaccine sera neutralization.

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In Vivo Selection of Campylobacter Isolates with High Levels of Fluoroquinolone Resistance Associated with gyrA Mutations and the Function of the CmeABC Efflux Pump

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.1.390-394.2003 ◽

2003 ◽

Vol 47 (1) ◽

pp. 390-394 ◽

Cited By ~ 159

Author(s):

Naidan Luo ◽

Orhan Sahin ◽

Jun Lin ◽

Linda O. Michel ◽

Qijing Zhang

Keyword(s):

Intestinal Tract ◽

Antimicrobial Agents ◽

Efflux Pump ◽

Single Point ◽

Point Mutations ◽

Fluoroquinolone Resistance ◽

Quinolone Antibiotics ◽

Single Point Mutations ◽

Selection Of

ABSTRACT Enrofloxacin treatment of chickens infected with fluoroquinolone(FQ)-sensitive Campylobacter promoted the emergence of FQ-resistant Campylobacter mutants which propagated in the intestinal tract and recolonized the chickens. The recovered isolates were highly resistant to quinolone antibiotics but remained susceptible to non-FQ antimicrobial agents. Specific single-point mutations in the gyrA gene and the function of the CmeABC efflux pump were linked to the acquired FQ resistance. These results reveal that Campylobacter is hypermutable in vivo under the selection pressure of FQ and highlight the need for the prudent use of FQ antibiotics.

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Epidemic and Molecular Characterization of Fluoroquinolone-Resistant Shigella Dysenteriae 1 Isolates From Calves with Diarrhea

10.21203/rs.3.rs-39629/v1 ◽

2020 ◽

Author(s):

Zhen Zhu ◽

Mingze Cao ◽

Weiwei Wang ◽

Liwei Zhang ◽

Guanhui Liu ◽

...

Keyword(s):

Molecular Characterization ◽

Virulence Genes ◽

Point Mutations ◽

Multidrug Resistant ◽

Gansu Province ◽

Shigella Dysenteriae ◽

Fluoroquinolone Resistance ◽

Resistant Strains ◽

And Control

Abstract Background: The widespread distribution of antimicrobial-resistant Shigella has become a recurrent challenge in many parts of the developing world. Previous studies indicate that the host of Shigella has expanded from humans to animals. This study aimed to investigate the prevalence of fluoroquinolone resistance and associated molecular characterization of S. dysenteriae 1 isolated from calves. Results: All 38 unduplicated S. dysenteriae 1 isolates were collected from calves in Gansu Province from October 2014 to December 2016. According to MLST and PFGE analysis, these isolates were separated into 4 and 28 genotypes, respectively. The most common STs identified were ST228 (34.21%, 13/38) and ST229 (39.47%, 15/38), which were first found in the present study. All isolates harbored virulence genes, and the incidence of the five virulence genes were ipaH (100%), ipaBCD (92.11%), stx (73.68%), ial (57.89%), and sen (28.95%). According to the results of antimicrobial susceptibilities, 76.32% (29/38) of S. dysenteriae isolates were resistant to fluoroquinolone and showed multidrug resistance. In a study on the polymorphism of QRDR of gyrA/B and parC/E genes, we identified two mutations in gyrA (Ser83→Leu and Asp87→Asn) and parC (Ser80→Ile and Ser83→Leu), respectively. Among them, 55.17% (16/29) of resistant strains had the gyrA point mutations (Ser83→Leu) and parC point mutation (Ser83→Leu). Moreover, 41.38% (12/29) of isolates had all five point mutations of gyrA and parC. In addition, the prevalence of the PMQR determinant genes was also investigated. All 29 fluoroquinolone-resistant isolates were positive for the aac(6’)-Ib-cr gene but negative for qepA, except SD001. In addition, only 6 (20.69%, 6/29) isolates harbored the qnr gene, including two with qnrB (6.90%, 2/29) and four with qnrS (13.79%, 4/29). Conclusion: Given the increased common emergence of multidrug resistant isolates, uninterrupted surveillance will be necessary to understand the actual epidemic burden and control this infection.

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gyrA Mutations in Ciprofloxacin-Resistant Bartonella bacilliformis Strains Obtained In Vitro

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.1.383-386.2003 ◽

2003 ◽

Vol 47 (1) ◽

pp. 383-386 ◽

Cited By ~ 20

Author(s):

Michael F. Minnick ◽

Zachary R. Wilson ◽

Laura S. Smitherman ◽

D. Scott Samuels

Keyword(s):

Single Point ◽

Point Mutations ◽

Dna Gyrase ◽

Wild Type ◽

Bartonella Bacilliformis ◽

E Coli ◽

A Subunit ◽

Resistant Strains ◽

Single Point Mutations

ABSTRACT We isolated and characterized mutants of Bartonella bacilliformis that are resistant to the fluoroquinolone antibiotic ciprofloxacin, which targets the A subunit of DNA gyrase. Mutants had single point mutations in the gyrA gene that changed either Asp-90 to Gly or Asp-95 to Asn and had 3- or 16-fold higher resistance, respectively, to ciprofloxacin than did wild-type B. bacilliformis. Asp-95 is homologous to Asp-87 of Escherichia coli GyrA and is a common residue mutated in fluoroquinolone-resistant strains of other bacteria. This is the first report of a mutation at an Asp-90 homologue, which corresponds to Asp-82 in E. coli GyrA.

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Detection of grlA and gyrA Mutations in 344 Staphylococcus aureus Strains

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.2.236 ◽

1998 ◽

Vol 42 (2) ◽

pp. 236-240 ◽

Cited By ~ 29

Author(s):

Tong Wang ◽

Mayumi Tanaka ◽

Kenichi Sato

Keyword(s):

Staphylococcus Aureus ◽

Direct Sequencing ◽

Single Point ◽

Point Mutations ◽

Single Strand Conformation Polymorphism ◽

Fluoroquinolone Resistance ◽

Polymorphism Analysis ◽

Ciprofloxacin Resistance ◽

Single Point Mutations ◽

Length Analysis

ABSTRACT Mutations in the grlA and gyrA genes of 344 clinical strains of Staphylococcus aureus isolated in 1994 in Japan were identified by combinations of single-strand conformation polymorphism analysis, restriction fragment length analysis, and direct sequencing to identify possible relationships to fluoroquinolone resistance. Five types of single-point mutations and four types of double mutations were observed in the grlA genes of 204 strains (59.3%). Four types of single-point mutations and four types of double mutations were found in the gyrA genes of 188 strains (54.7%). Among them, the grlA mutation of TCC→TTC or TAC (Ser-80→Phe or Tyr) and the gyrAmutation of TCA→TTA (Ser-84→Leu) were principal, being detected in 137 (39.8%) and 121 (35.9%) isolates, respectively. ThegrlA point mutations of CAT→CAC (His-77 [silent]), TCA→CCA (Ser-81→Pro), and ATA→ATT (Ile-100 [silent]) were novel, as was the GAC→GGC (Asp-73→Gly) change in gyrA. A total of 15 types of mutation combinations within both genes were related to ciprofloxacin resistance (MIC ≥ 3.13 μg/ml) and were present in 193 mutants (56.1%). Strains containing mutations in both genes were highly resistant to ciprofloxacin (MIC at which 50% of the isolates are inhibited [MIC50] = 50 μg/ml). Those with the Ser-80→Phe or Tyr alteration in grlA but wild-typegyrA showed a lower level of ciprofloxacin resistance (MIC50 ≤ 12.5 μg/ml). Levofloxacin was active against 68 of 193 isolates (35.2%) with mutations at codon 80 of grlAin the presence or absence of a concomitant mutation at codon 73, 84, or 88 in gyrA (MIC ≤ 6.25 μg/ml). The new fluoroquinolone DU-6859a showed good activity with 186 of 193 isolates (96.4%) for which the MIC was ≤6.25 μg/ml.

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