scholarly journals High-Frequency Transduction of Antibiotic Resistance in Pseudomonas aeruginosa by a Wild-Type Bacteriophage with Restricted Specificity for Recipient Strains

1999 ◽  
Vol 18 (2) ◽  
pp. 152-154 ◽  
Author(s):  
J. Blahová ◽  
K. Králiková ◽  
V. Krčméry Sr. ◽  
N. Bartoníková
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
High Frequency ◽  
Wild Type

scholarly journals Antibiotic Resistance Evolution Is Contingent on the Quorum-Sensing Response in Pseudomonas aeruginosa

2019 ◽  
Vol 36 (10) ◽  
pp. 2238-2251 ◽  
Author(s):  
Sara Hernando-Amado ◽  
Fernando Sanz-García ◽  
José Luis Martínez
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Quorum Sensing ◽  
Wild Type ◽  
Resistance Mutations ◽  
Epistatic Interactions ◽  
Adaptive Mutations ◽  
Resistance Evolution ◽  
Evolutionary Trajectories

Abstract Different works have explored independently the evolution toward antibiotic resistance and the role of eco-adaptive mutations in the adaptation to a new habitat (as the infected host) of bacterial pathogens. However, knowledge about the connection between both processes is still limited. We address this issue by comparing the evolutionary trajectories toward antibiotic resistance of a Pseudomonas aeruginosa lasR defective mutant and its parental wild-type strain, when growing in presence of two ribosome-targeting antibiotics. Quorum-sensing lasR defective mutants are selected in P. aeruginosa populations causing chronic infections. Further, we observed they are also selected in vitro as a first adaptation for growing in culture medium. By using experimental evolution and whole-genome sequencing, we found that the evolutionary trajectories of P. aeruginosa in presence of these antibiotics are different in lasR defective and in wild-type backgrounds, both at the phenotypic and the genotypic levels. Recreation of a set of mutants in both genomic backgrounds (either wild type or lasR defective) allowed us to determine the existence of negative epistatic interactions between lasR and antibiotic resistance determinants. These epistatic interactions could lead to mutual contingency in the evolution of antibiotic resistance when P. aeruginosa colonizes a new habitat in presence of antibiotics. If lasR mutants are selected first, this would constraint antibiotic resistance evolution. Conversely, when resistance mutations (at least those studied in the present work) are selected, lasR mutants may not be selected in presence of antibiotics. These results underlie the importance of contingency and epistatic interactions in modulating antibiotic resistance evolution.

scholarly journals An improved Xer-cise technology for the generation of multiple unmarked mutants in Mycobacteria

2019 ◽  
Author(s):  
Yves-Marie Boudehen ◽  
Maximillian Wallat ◽  
Philippe Rousseau ◽  
Olivier Neyrolles ◽  
Claude Gutierrez
Keyword(s):  
Antibiotic Resistance ◽  
High Frequency ◽  
Mycobacterium Smegmatis ◽  
Bacterial Species ◽  
Wild Type ◽  
Model Species ◽  
Mycobacterial Genome ◽  
Bacterial Chromosomes ◽  
Genetic Constructs ◽  
Zeocin Resistance

SummaryXer-cise is a technique using antibiotic resistance cassettes flanked by dif sites allowing spontaneous and accurate excision from bacterial chromosomes with a high frequency through the action of the cellular recombinase XerCD. Here, we report a significant improvement of Xer-cise in Mycobacteria. Zeocin-resistance cassettes flanked by variants of the natural Mycobacterium tuberculosis dif site were constructed and shown to be effective tools to construct multiple unmarked mutations in M. tuberculosis and in the model species Mycobacterium smegmatis. The dif site variants harbor mutations in the central region and can therefore not recombine with the wild type or other variants, resulting in mutants of increased genetic stability. The herein described method should be generalizable to virtually any transformable bacterial species.Method summarydif-ZeoR-dif cassettes are used to replace non-essential genes in mycobacterial genome through recombineering. Spontaneous excision of the cassette is carried out under the action of the recombinase XerCD, resulting in unmarked deletions. Subsequent rounds of mutagenesis using cassettes flanked by a range of dif site variants allow construction of multiple mutants in which the different dif sites cannot recombine which each other, yielding stable genetic constructs.

scholarly journals PA3225 Is a Transcriptional Repressor of Antibiotic Resistance Mechanisms in Pseudomonas aeruginosa

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Clayton W. Hall ◽  
Li Zhang ◽  
Thien-Fah Mah
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Efflux Pump ◽  
Regulatory Region ◽  
Resistance Mechanisms ◽  
Wild Type ◽  
Type Vi Secretion System ◽  
Planktonic Cells ◽  
Content Type ◽  
Dependent Protein

ABSTRACT The tssABC1 locus is part of the Hcp secretion island I (HSI-I) type VI secretion system (T6SS) in Pseudomonas aeruginosa. Previous work implicated the tssC1 gene in P. aeruginosa biofilm-specific antibiotic resistance, and tssC1 is preferentially expressed in biofilms compared to planktonic cells. Using a DNA-dependent protein pulldown approach, we discovered that PA3225, an uncharacterized LysR-type transcriptional regulator, specifically bound to the tssABC1 upstream regulatory region. The deletion of PA3225 led to a 2-fold decrease in tssA1 expression levels in planktonic cells compared to the wild type, and tssA1 expression was slightly reduced in ΔPA3225 biofilms compared to wild-type biofilms. Intriguingly, further investigations revealed that the ΔPA3225 mutant was less susceptible to multiple, structurally unrelated antibiotics with various mechanisms of action when grown planktonically. The ΔPA3225 mutant was additionally more resistant to ciprofloxacin when grown in a biofilm. The decreased antibiotic susceptibility of the ΔPA3225 strain was linked to the transcriptional upregulation of the MexAB-OprM efflux pump. By using transcriptome sequencing (RNA-seq), other PA3225-regulated genes were identified, and the products of these genes, such as the putative ABC transporter PA3228, may also contribute to antibiotic resistance.

scholarly journals The Glycerol-3-Phosphate Permease GlpT Is the Only Fosfomycin Transporter in Pseudomonas aeruginosa

2009 ◽  
Vol 191 (22) ◽  
pp. 6968-6974 ◽  
Author(s):  
Alfredo Castañeda-García ◽  
Alexandro Rodríguez-Rojas ◽  
Javier R. Guelfo ◽  
Jesús Blázquez
Keyword(s):  
Pseudomonas Aeruginosa ◽  
High Frequency ◽  
Wild Type ◽  
Apparent Lack ◽  
Fosfomycin Resistance ◽  
Function Relationship ◽  
Relationship Of ◽  
Specific Transport System ◽  
Insertion Mutants

ABSTRACT Fosfomycin is transported into Escherichia coli via both glycerol-3-phosphate (GlpT) and a hexose phosphate transporter (UhpT). Consequently, the inactivation of either glpT or uhpT confers increased fosfomycin resistance in this species. The inactivation of other genes, including ptsI and cyaA, also confers significant fosfomycin resistance. It has been assumed that identical mechanisms are responsible for fosfomycin transport into Pseudomonas aeruginosa cells. The study of an ordered library of insertion mutants in P. aeruginosa PA14 demonstrated that only insertions in glpT confer significant resistance. To explore the uniqueness of this resistance target in P. aeruginosa, the linkage between fosfomycin resistance and the use of glycerol-3-phosphate was tested. Fosfomycin-resistant (Fos-R) mutants were obtained in LB and minimal medium containing glycerol as the sole carbon source at a frequency of 10−6. However, no Fos-R mutants grew on plates containing fosfomycin and glycerol-3-phosphate instead of glycerol (mutant frequency, ≤5 × 10−11). In addition, 10 out of 10 independent spontaneous Fos-R mutants, obtained on LB-fosfomycin, harbored mutations in glpT, and in all cases the sensitivity to fosfomycin was recovered upon complementation with the wild-type glpT gene. The analysis of these mutants provides additional insights into the structure-function relationship of glycerol-3-phosphate the transporter in P. aeruginosa. Studies with glucose-6-phosphate and different mutant derivatives strongly suggest that P. aeruginosa lacks a specific transport system for this sugar. Thus, glpT seems to be the only fosfomycin resistance mutational target in P. aeruginosa. The high frequency of Fos-R mutations and their apparent lack of fitness cost suggest that Fos-R variants will be obtained easily in vivo upon the fosfomycin treatment of P. aeruginosa infections.

scholarly journals An improved Xer-cise technology for the generation of multiple unmarked mutants in Mycobacteria

BioTechniques ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 106-110 ◽  
Author(s):  
Yves-Marie Boudehen ◽  
Maximilian Wallat ◽  
Philippe Rousseau ◽  
Olivier Neyrolles ◽  
Claude Gutierrez
Keyword(s):  
Antibiotic Resistance ◽  
Mycobacterium Tuberculosis ◽  
Central Region ◽  
High Frequency ◽  
Mycobacterium Smegmatis ◽  
Bacterial Species ◽  
Wild Type ◽  
Model Species ◽  
Bacterial Chromosomes ◽  
Zeocin Resistance

Xer-cise is a technique using antibiotic resistance cassettes flanked by dif sites allowing spontaneous and accurate excision from bacterial chromosomes with a high frequency through the action of the cellular recombinase XerCD. Here, we report a significant improvement of Xer-cise in Mycobacteria. Zeocin resistance cassettes flanked by variants of the natural Mycobacterium tuberculosis dif site were constructed and shown to be effective tools to construct multiple unmarked mutations in M. tuberculosis and in the model species Mycobacterium smegmatis. The dif site variants harbor mutations in the central region and can therefore not recombine with the wild-type or other variants, resulting in mutants of increased genetic stability. The herein described method should be generalizable to virtually any transformable bacterial species.

scholarly journals Overexpression of MexCD-OprJ Reduces Pseudomonas aeruginosa Virulence by Increasing Its Susceptibility to Complement-Mediated Killing

2014 ◽  
Vol 58 (4) ◽  
pp. 2426-2429 ◽  
Author(s):  
Inmaculada Martínez-Ramos ◽  
Xavier Mulet ◽  
Bartolomé Moyá ◽  
Mariette Barbier ◽  
Antonio Oliver ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Immune System ◽  
Antimicrobial Resistance ◽  
Type Strain ◽  
Wild Type Strain ◽  
Host Immune System ◽  
Wild Type ◽  
Content Type ◽  
Increased Susceptibility

ABSTRACTWe evaluated the resistance to complement-mediated killing of a collection of isogenicPseudomonas aeruginosastrains expressing different antimicrobial resistance phenotypes. Only thenfxBmutant demonstrated increased susceptibility to complement compared with that for the wild-type strain. This increment was due to the overexpression of MexCD-OprJ, which led to increased C3 opsonization and a reduced ability to infect the lungs of mice. Our results show that the acquisition of antibiotic resistance may alter the interplay ofP. aeruginosawith the host immune system.

scholarly journals Influence of OprM expression on multiple antibiotic resistance in Pseudomonas aeruginosa.

1997 ◽  
Vol 41 (9) ◽  
pp. 2009-2012 ◽  
Author(s):  
K K Wong ◽  
K Poole ◽  
N Gotoh ◽  
R E Hancock
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Antimicrobial Agents ◽  
Multiple Antibiotic Resistance ◽  
Wild Type ◽  
Beta Lactams ◽  
Efflux System ◽  
Cloned Gene

MexA-MexB-OprM is an efflux system in Pseudomonas aeruginosa. OprM overproduced from the cloned gene was able to complement OprM-deficient mutants but did not alter the resistance of a wild-type P. aeruginosa strain to the different antimicrobial agents tested. This suggests that OprM cannot function by itself to efflux antibiotics, including beta-lactams targeted to the periplasm.

scholarly journals 201. Frequency of Pseudomonas aeruginosa (PA) Discrete Inner Colonies and Comparison of Minimal Inhibitory Concentration (MIC) Values between Parent and Inner Colony Isolates Following Fosfomycin Disk Diffusion (DD) Testing

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S123-S123
Author(s):  
Dina Zheng ◽  
Morgan L Bixby ◽  
Elizabeth C Smith ◽  
Jadyn C Anderson ◽  
Phillip J Bergen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
High Frequency ◽  
Susceptibility Testing ◽  
Inhibitory Concentration ◽  
Multidrug Resistant ◽  
Broth Microdilution ◽  
Zone Of Inhibition ◽  
Bmd Testing

Abstract Background Fosfomycin combination therapy is a potential approach for treatment of multidrug-resistant (MDR) PA infections despite a lack of approved susceptibility breakpoints for this organism. While DD testing is commonly used for fosfomycin, growth of discrete inner colonies (IC) within the zone of inhibition has been observed for multiple organisms following DD. Criteria recommended by CLSI and EUCAST are contradictory for interpreting these inner colonies. We therefore sought to determine the frequency of inner colonies and MIC differences between PA parent-inner colony pairs from an international isolate collection. Methods A convenience collection of 198 clinical PA isolates from three U.S institutions (n = 82), two Australian institutions (n = 72), and the CDC & FDA Antibiotic Resistance Isolate Bank (n = 44) were included. Fosfomycin MIC values were determined in duplicate on separate days by DD and broth microdilution (BMD) testing. For parent isolates with discrete IC observed during DD, IC isolates were subcultured and MIC values were determined and then compared to their corresponding parent isolates. MIC values were interpreted using CLSI Escherichia coli (EC) breakpoints (susceptible: MIC ≤ 64 μg/mL, intermediate: MIC = 128, resistant: MIC ≥ 256 μg/mL). Results Parent isolate BMD MIC values ranged from < 4 to > 256 μg/mL while IC isolate BMD MIC values ranged from 128 to > 1024 μg/mL. MIC50/90 values were 128/256 μg/mL and > 1024/ > 1024 μg/mL for the parent and IC isolates, respectively. A high frequency of 45% (89/198) of parent isolates displayed discrete IC which also demonstrated a higher frequency of resistance (97.8%) compared to the parent isolates (23.7%). Conclusion IC MIC values were higher overall compared to parent MIC values, with an average fold difference of ~18 between the parent-inner colony pairs. The frequency of IC found in this study (45%) is considerably higher than previously observed in EC clinical isolates. These data highlight the need to further investigate the importance of these IC and warrant caution for extrapolation of EC breakpoints for fosfomycin susceptibility testing against PA. Disclosures All Authors: No reported disclosures

scholarly journals Exploring the success of Brazilian endemic clone Pseudomonas aeruginosa ST277 and its association with the CRISPR-Cas system type I-C

2019 ◽  
Author(s):  
Melise Chaves Silveira ◽  
Cláudio Marcos Rocha-de-Souza ◽  
Rodolpho Mattos Albano ◽  
Ivson Cassiano de Oliveira Santos ◽  
Ana Paula D'Alincourt Carvalho-Assef
Keyword(s):  
United States ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
High Frequency ◽  
Genomic Islands ◽  
Type I ◽  
Virulence Determinants ◽  
Resistance Determinants ◽  
System Type ◽  
Gene Coding

Abstract Background The Brazilian endemic clone Pseudomonas aeruginosa ST277 carry important antibiotic resistance determinants, highlighting the gene coding for SPM-1 carbapenamase. However, the resistance and persistence of this clone is apparently restricted to Brazilian territory. To completely understand the differences between strains from Brazil from the ones isolated in other countries, we phylogenetically examined 43 P. aeruginosa ST277 genomes as well as analyzed virulence and resistance genes, evaluated the distribution of genomic islands and assessed in detail the characteristics of the CRISPR-Cas immunity system in these isolates. Results The Brazilian genomes presented a typical set of resistance and virulence determinants, genomic islands and a high frequency of the CRISPR-Cas system type I-C. Upon phylogeny results, even if ST277 genomes are closely related we can see important differences among the strains isolated from China, Mexico and United States when compared to others, most of them from Brazil. We also observed a standard CRISPR spacers content for ST277, confirming a strong link between phylogeny and spacer acquisition. Conclusions Based on our findings, Pseudomonas aeruginosa ST277 strains circulating in Brazil have acquired a few distinctive genetic elements that contributing to their resistance, pathogenicity and success when compared to strains from other countries.

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