scholarly journals Rapid and robust evolution of collateral sensitivity in Pseudomonas aeruginosa antibiotic-resistant mutants

2020 ◽  
Vol 6 (32) ◽  
pp. eaba5493
Author(s):  
Sara Hernando-Amado ◽  
Fernando Sanz-García ◽  
José Luis Martínez
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Rational Design ◽  
Antibiotic Resistant ◽  
Trade Off ◽  
Collateral Sensitivity ◽  
Trade Offs ◽  
Resistant Mutants ◽  
Antibiotic Resistant Mutants

The analysis of trade-offs, as collateral sensitivity, associated with the acquisition of antibiotic resistance, is mainly based on the use of model strains. However, the possibility of exploiting these trade-offs for fighting already resistant isolates has not been addressed in depth, despite the fact that bacterial pathogens are frequently antibiotic-resistant, forming either homogeneous or heterogeneous populations. Using a set of Pseudomonas aeruginosa-resistant mutants, we found that ceftazidime selects pyomelanogenic tobramycin-hypersusceptible mutants presenting chromosomal deletions in the analyzed genetic backgrounds. Since pyomelanogenic resistant mutants frequently coexist with other morphotypes in patients with cystic fibrosis, we analyzed the exploitation of this trade-off to drive extinction of heterogeneous resistant populations by using tobramycin/ceftazidime alternation. Our work shows that this approach is feasible because phenotypic trade-offs associated with the use of ceftazidime are robust. The identification of conserved collateral sensitivity networks may guide the rational design of evolution-based antibiotic therapies in P. aeruginosa infections.

scholarly journals Social Behavior of Antibiotic Resistant Mutants Within Pseudomonas aeruginosa Biofilm Communities

2019 ◽  
Vol 10 ◽  
Author(s):  
Estrella Rojo-Molinero ◽  
María D. Macià ◽  
Antonio Oliver
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Social Behavior ◽  
Antibiotic Resistant ◽  
Resistant Mutants ◽  
Antibiotic Resistant Mutants

scholarly journals Phage steering of antibiotic-resistance evolution in the bacterial pathogen, Pseudomonas aeruginosa

2020 ◽  
Vol 2020 (1) ◽  
pp. 148-157 ◽  
Author(s):  
James Gurney ◽  
Léa Pradier ◽  
Joanne S Griffin ◽  
Claire Gougat-Barbera ◽  
Benjamin K Chan ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Bacterial Pathogen ◽  
Antibiotic Sensitivity ◽  
Resistant Bacteria ◽  
Phage Resistance ◽  
Antibiotic Resistant ◽  
Trade Off

Abstract Background and objectives Antimicrobial resistance is a growing global concern and has spurred increasing efforts to find alternative therapeutics. Bacteriophage therapy has seen near constant use in Eastern Europe since its discovery over a century ago. One promising approach is to use phages that not only reduce bacterial pathogen loads but also select for phage resistance mechanisms that trade-off with antibiotic resistance—so called ‘phage steering’. Methodology Recent work has shown that the phage OMKO1 can interact with efflux pumps and in so doing select for both phage resistance and antibiotic sensitivity of the pathogenic bacterium Pseudomonas aeruginosa. We tested the robustness of this approach to three different antibiotics in vitro (tetracycline, erythromycin and ciprofloxacin) and one in vivo (erythromycin). Results We show that in vitro OMKO1 can reduce antibiotic resistance of P. aeruginosa (Washington PAO1) even in the presence of antibiotics, an effect still detectable after ca.70 bacterial generations in continuous culture with phage. Our in vivo experiment showed that phage both increased the survival times of wax moth larvae (Galleria mellonella) and increased bacterial sensitivity to erythromycin. This increased antibiotic sensitivity occurred both in lines with and without the antibiotic. Conclusions and implications Our study supports a trade-off between antibiotic resistance and phage sensitivity. This trade-off was maintained over co-evolutionary time scales even under combined phage and antibiotic pressure. Similarly, OMKO1 maintained this trade-off in vivo, again under dual phage/antibiotic pressure. Our findings have implications for the future clinical use of steering in phage therapies. Lay Summary: Given the rise of antibiotic-resistant bacterial infection, new approaches to treatment are urgently needed. Bacteriophages (phages) are bacterial viruses. The use of such viruses to treat infections has been in near-continuous use in several countries since the early 1900s. Recent developments have shown that these viruses are not only effective against routine infections but can also target antibiotic resistant bacteria in a novel, unexpected way. Similar to other lytic phages, these so-called ‘steering phages’ kill the majority of bacteria directly. However, steering phages also leave behind bacterial variants that resist the phages, but are now sensitive to antibiotics. Treatment combinations of these phages and antibiotics can now be used to greater effect than either one independently. We evaluated the impact of steering using phage OMKO1 and a panel of three antibiotics on Pseudomonas aeruginosa, an important pathogen in hospital settings and in people with cystic fibrosis. Our findings indicate that OMKO1, either alone or in combination with antibiotics, maintains antibiotic sensitivity both in vitro and in vivo, giving hope that phage steering will be an effective treatment option against antibiotic-resistant bacteria.

scholarly journals The Effects of Sub-inhibitory Antibiotic Concentrations on Pseudomonas aeruginosa: Reduced Susceptibility Due to Mutations

2021 ◽  
Vol 12 ◽  
Author(s):  
Kay A. Ramsay ◽  
Sharla M. McTavish ◽  
Samuel J. T. Wardell ◽  
Iain L. Lamont
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Susceptibility ◽  
Resistant Bacteria ◽  
Antibiotic Exposure ◽  
Aminoglycoside Resistance ◽  
Antibiotic Resistant ◽  
Aminoglycoside Resistance Genes ◽  
Reference Strains ◽  
Antibiotic Resistant Mutants

Pseudomonas aeruginosa chronically infects in the lungs of people with cystic fibrosis and other forms of lung disease. Infections are treated with antibiotics, but over time, the bacteria acquire mutations that reduce their antibiotic susceptibility. The effects of inhibitory amounts of antibiotics in selecting for antibiotic-resistant mutants have been well studied. However, the concentrations of antibiotics that reach infecting bacteria can be sub-inhibitory and but may nonetheless promote emergence of antibiotic-resistant bacteria. Therefore, the aim of this research was to investigate the effects of sub-inhibitory concentrations of antibiotics on the antibiotic susceptibility of P. aeruginosa. Two P. aeruginosa reference strains, PAO1 and PA14, and six isolates from individuals with cystic fibrosis were studied. The bacteria were passaged in the presence of antibiotics (ceftazidime, ciprofloxacin, meropenem or tobramycin) at sub-inhibitory amounts. Fifteen populations of bacteria (up to five per strain) were exposed to each of the four antibiotics. Antibiotic susceptibility was determined following 10 passages on agar supplemented with antibiotic and compared with susceptibility prior to antibiotic exposure. Antibiotic exposure resulted in susceptibility being significantly (>2-fold) reduced for 13 of the 60 populations. Seven samples had reduced susceptibility to ciprofloxacin, three to tobramycin, two to ceftazidime and one to meropenem. Whole-genome sequencing revealed the mutations arising following antibiotic exposure. Mutants with reduced antibiotic susceptibility had mutations in genes known to affect antibiotic resistance, including regulators of efflux pumps (mexR, mexS, mexZ and nalC) and the fusA1 gene that is associated with aminoglycoside resistance. Genes not previously associated with resistance, including gacS, sigX and crfX and two genes with no known function, were also mutated in some isolates with reduced antibiotic susceptibility. Our results show that exposure to sub-inhibitory amounts of antibiotics can select for mutations that reduce the susceptibility of P. aeruginosa to antibiotics and that the profile of mutations is different from that arising during selection with inhibitory antibiotic concentrations. It is likely that exposure to sub-inhibitory amounts of antibiotics during infection contributes to P. aeruginosa becoming antibiotic-resistant.

scholarly journals Dynamics of Mutator and Antibiotic-Resistant Populations in a Pharmacokinetic/Pharmacodynamic Model of Pseudomonas aeruginosa Biofilm Treatment

2011 ◽  
Vol 55 (11) ◽  
pp. 5230-5237 ◽  
Author(s):  
María D. Macià ◽  
José L. Pérez ◽  
Soeren Molin ◽  
Antonio Oliver
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Resistance Development ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Mutant Prevention Concentration ◽  
Resistant Mutants

ABSTRACTBiofilm growth, antibiotic resistance, and mutator phenotypes are key components of chronic respiratory infections byPseudomonas aeruginosain cystic fibrosis patients. We examined the dynamics of mutator and antibiotic-resistant populations inP. aeruginosaflow-cell biofilms, using fluorescently tagged PAO1 and PAOMS (mutator [mutS] derivative) strains. Two-day-old biofilms were treated with ciprofloxacin (CIP) for 4 days (t4) at 2 μg/ml, which correlated with the mutant prevention concentration (MPC) and provided an AUC/MIC ratio of 384 that should predict therapeutic success. Biofilms were monitored by confocal laser scanning microscopy (CLSM), and the numbers of viable cells and resistant mutants (4- and 16-fold MICs) were determined. Despite optimized pharmacokinetic/pharmacodynamic (PK/PD) parameters, CIP treatment did not suppress resistance development inP. aeruginosabiofilms. One-step resistant mutants (MexCD-OprJ or MexEF-OprN overexpression) were selected for both strains, while two-step resistant mutants (additional GyrA or GyrB mutation) were readily selected only from the mutator strain. CLSM analysis of competition experiments revealed that PAOMS, even when inoculated at a 0.01 proportion, took over the whole biofilm after only 2 days of CIP treatment outnumbering PAO1 by 3 log at t4. Our results show that mutational mechanisms play a major role in biofilm antibiotic resistance and that theoretically optimized PK/PD parameters fail to suppress resistance development, suggesting that the increased antibiotic tolerance driven by the special biofilm physiology and architecture may raise the effective MPC, favoring gradual mutational resistance development, especially in mutator strains. Moreover, the amplification of mutator populations under antibiotic treatment by coselection with resistance mutations is for the first time demonstratedin situforP. aeruginosabiofilms.

scholarly journals Associations between Bacteriophage Resistance and Antibiotic Resistance Phenotypes in Laboratory and Clinical strains of Salmonella Typhimurium

2019 ◽  
Author(s):  
Md Jalal Uddin ◽  
Juhee Ahn
Keyword(s):  
Antibiotic Resistance ◽  
Salmonella Typhimurium ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Bacteriophage P22 ◽  
Antibiotic Resistant ◽  
Antibiotic Susceptibilities ◽  
Resistant Mutants ◽  
Mutant Frequency ◽  
Antibiotic Resistant Mutants

Abstract Background Bacteriophages have received great attention as alternative over antibiotics due to the host specificity. Therefore, this study was designed to evaluate the associations between bacteriophage-insensitive (BI) and antibiotic-resistant mutants of Salmonella Typhimurium strains. Bacteriophage-sensitive Salmonella Typhimurium ATCC 19585 (BSSTWT), ciprofloxacin-induced S. Typhimurium ATCC 19585 (BSSTCIP), S. Typhimurium KCCM 40253 (BSSTLAB), and clinically isolated multidrug-resistant S. Typhimurium CCARM 8009 (BSSTMDR) were used to induce the bacteriophage-insensitive mutants (BISTWT, BISTCIP, BISTLAB, and BISTMDR) against bacteriophage P22. Results The numbers of BSSTWT, BSSTCIP, and BSSTLAB were reduced by P22 (>3 log), while the least lytic activity was observed for BSSTMDR. BSSTWT treated with P22 showed the large variation in the cell state (CV>40%) and highest mutant frequency (62%), followed by 25% for STCIP. The least similarities between BSSTWT and BISTWT were observed at P22 and PBST-13 (<12%). The antibiotic susceptibilities were not significantly changed or slightly increased against BISTWT, BISTCIP, BISTLAB, and BISTMDR. The relative expression levels of bacteriophage-binding receptor-related genes (btuB, fhuA, fliK, fljB, ompC, ompF, rfaL, and tolC) were decreased in BISTCIP and BSSTMDR. Conclusion The results could pave the way for the application of bacteriophages as an alternative to control antibiotic-resistant bacteria.

scholarly journals NEW ANTIBIOTIC RESISTANCE LOCI IN THE RIBOSOMAL REGION OF YEAST MITOCHONDRIAL DNA

Genetics ◽  
1980 ◽  
Vol 94 (1) ◽  
pp. 69-92
Author(s):  
Jeffrey A Knight
Keyword(s):  
Mitochondrial Dna ◽  
Antibiotic Resistance ◽  
Resistant Mutant ◽  
Cross Resistance ◽  
Antibiotic Resistant ◽  
Resistance Patterns ◽  
Genetic Techniques ◽  
Resistant Mutants ◽  
Yeast Mitochondrial Dna ◽  
Antibiotic Resistant Mutants

ABSTRACT A large number of mitochondrial antibiotic-resistant mutants have been isolated following mutagenesis with manganese. These include several different phenotypic classes of mutants, as distinguished by cross-resistance patterns, that have been found to be allelic at capl or eryl; some have been found to be heteroalle1ic.—Seven chloramphenicol-resistant mutants have been identified that are nonallelic by recombination tests with the three loci (capl, spil and eryl) previously identified in the ribosomal region. Four of these are allelic with each other and define a new locus, cap3; two others are allelic and define another new locus, cap2; the seventh maps at yet a different locus, cap4. One new spiramycin-resistant mutant has been identified that defines still another new locus, spi2. A variety of genetic techniques have been used to map these loci within the ribosomal region of the mitochondrial genome.—Manganese has been shown to be effective in inducing the mutation from ω- to ωn in many mutants that experience a simultaneous mutation at the closely linked capl locus. The ωn mutation has also been described in the capl mutant, and this locus has been shown to be more closely linked to o than capl is to ω.

ASSOCIATION BETWEEN ANTIBIOTIC RESISTANCE AND INEFFECTIVENESS IN MUTANT STRAINS OF RHIZOBIUM SPP.

1964 ◽  
Vol 10 (2) ◽  
pp. 221-233 ◽  
Author(s):  
E. A. Schwinghamer
Keyword(s):  
Antibiotic Resistance ◽  
Kanamycin Resistance ◽  
Cross Resistance ◽  
Antibiotic Resistant ◽  
Mutant Strains ◽  
Rapid Dissolution ◽  
Rhizobium Spp ◽  
Resistant Mutants ◽  
Neomycin Resistance ◽  
Antibiotic Resistant Mutants

Loss of effectiveness was found to be closely associated with mutation to viomycin resistance and neomycin resistance in strains representing three cross-inoculation groups of Rhizobium—R. leguminosarum, R. trifolii, and R. meliloti. Twenty-nine of 33 mutant clones, selected from 11 normally effective parent strains for resistance to viomycin, were uniformly ineffective. Both viomycin resistance and ineffectiveness remained unchanged in clones reisolated from nodules. Fifteen of 16 clones selected for neomycin resistance from eight normally effective strains were also ineffective, fn contrast, loss of effectiveness occurred only infrequently in clones resistant to kanamycin or polymyxin, and was not observed at all in streptomycin-resistant mutants. Cytologically, ineffective nodules were characterized by rapid dissolution of bacteroid-containing tissue. Ability to form nodules (infectiveness) on the homologous host was retained in all antibiotic-resistant mutants. Full cross resistance was noted for strains selected for resistance to viomycin and neomycin. Kanamycin resistance conferred resistance to neomycin but not to viomycin. Implications of the marker-associated changes are considered in relation to some problems in Rhizobium genetics and physiology.

scholarly journals Metabotypes of Pseudomonas aeruginosa Correlate with Antibiotic Resistance, Virulence and Clinical Outcome in Cystic Fibrosis Chronic Infections

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 63
Author(s):  
Oriane Moyne ◽  
Florence Castelli ◽  
Dominique J. Bicout ◽  
Julien Boccard ◽  
Boubou Camara ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Multiscale Analysis ◽  
Resistant Bacteria ◽  
Chronic Infections ◽  
Antibiotic Resistant ◽  
Causes Of Mortality ◽  
Lung Infections ◽  
Clinical Measurements

Pseudomonas aeruginosa (P.a) is one of the most critical antibiotic resistant bacteria in the world and is the most prevalent pathogen in cystic fibrosis (CF), causing chronic lung infections that are considered one of the major causes of mortality in CF patients. Although several studies have contributed to understanding P.a within-host adaptive evolution at a genomic level, it is still difficult to establish direct relationships between the observed mutations, expression of clinically relevant phenotypes, and clinical outcomes. Here, we performed a comparative untargeted LC/HRMS-based metabolomics analysis of sequential isolates from chronically infected CF patients to obtain a functional view of P.a adaptation. Metabolic profiles were integrated with expression of bacterial phenotypes and clinical measurements following multiscale analysis methods. Our results highlighted significant associations between P.a “metabotypes”, expression of antibiotic resistance and virulence phenotypes, and frequency of clinical exacerbations, thus identifying promising biomarkers and therapeutic targets for difficult-to-treat P.a infections

scholarly journals The spatial profiles and metabolic capabilities of microbial populations impact the growth of antibiotic-resistant mutants

2015 ◽  
Vol 12 (107) ◽  
pp. 20150018 ◽  
Author(s):  
Karishma S. Kaushik ◽  
Nalin Ratnayeke ◽  
Parag Katira ◽  
Vernita D. Gordon
Keyword(s):  
Antibiotic Resistance ◽  
Bacterial Species ◽  
Global Scale ◽  
Antibiotic Resistant ◽  
Wide Range ◽  
Nutrient Environment ◽  
Resistant Mutants ◽  
Cell Densities ◽  
Opportunistic Human Pathogen ◽  
Antibiotic Resistant Mutants

Antibiotic resistance adversely affects clinical and public health on a global scale. Using the opportunistic human pathogen Pseudomonas aeruginosa , we show that increasing the number density of bacteria, on agar containing aminoglycoside antibiotics, can non-monotonically impact the survival of antibiotic-resistant mutants. Notably, at high cell densities, mutant survival is inhibited. A wide range of bacterial species can inhibit antibiotic-resistant mutants. Inhibition results from the metabolic breakdown of amino acids, which results in alkaline by-products. The consequent increase in pH acts in conjunction with aminoglycosides to mediate inhibition. Our work raises the possibility that the manipulation of microbial population structure and nutrient environment in conjunction with existing antibiotics could provide therapeutic approaches to combat antibiotic resistance.

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