Emerging Phage Resistance in Pseudomonas aeruginosa PAO1 Is Accompanied by an Enhanced Heterogeneity and Reduced Virulence

Bacterial surface structures of a proteinic nature and glycoconjugates contribute to biofilm formation and provide shields to host defense mechanisms (e.g., the complement system and phagocytosis). A loss or alteration of these molecules, leading to phage resistance, could result in fewer virulent bacteria. In this study, we evaluate the biology and phenotype changes in Pseudomonas aeruginosa PAO1 phage-resistant clones, which emerge in phage-treated biofilms. We characterize these clones for phage-typing patterns, antibiotic resistance, biofilm formation, pathogenicity, and interactions with the innate immune system. Another important question that we address is whether phage-resistant mutants are also generated incidentally, despite the phage treatment-selective pressure, as the natural adaptation of the living biofilm population. It is found that the application of different phages targeting a particular receptor selects similar phage resistance patterns. Nevertheless, this results in a dramatic increase in the population heterogeneity, giving over a dozen phage-typing patterns, compared to one of the untreated PAO1 sessile forms. We also confirm the hypothesis that “phage-resistant bacteria are more susceptible to antibiotics and host-clearance mechanisms by the immune system”. These findings support phage application in therapy, although the overall statement that phage treatment selects the less virulent bacterial population should be further verified using a bigger collection of clinical strains.

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Synergistic Effect of Biogenics Derived from Potential Probiotics Together with Zingerone Against Biofilm Formation by Pseudomonas aeruginosa PAO1

Probiotics and Antimicrobial Proteins ◽

10.1007/s12602-021-09763-x ◽

2021 ◽

Author(s):

Swati Chandla ◽

Kusum Harjai ◽

Geeta Shukla

Keyword(s):

Pseudomonas Aeruginosa ◽

Synergistic Effect ◽

Biofilm Formation ◽

Pseudomonas Aeruginosa Pao1

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Phytochemical Profiling of Lavandula coronopifolia Poir. Aerial Parts Extract and Its Larvicidal, Antibacterial, and Antibiofilm Activity Against Pseudomonas aeruginosa

Molecules ◽

10.3390/molecules26061710 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1710

Author(s):

Mahmoud Emam ◽

Doaa R. Abdel-Haleem ◽

Maha M. Salem ◽

Lina Jamil M. Abdel-Hafez ◽

Rasha R. Abdel Latif ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Wild Plant ◽

Resistant Bacteria ◽

Control Group ◽

Antibiofilm Activity ◽

Left Behind ◽

Aerial Parts ◽

Socioeconomic Burden ◽

Cytochrome P 450

Infections associated with the emergence of multidrug resistance and mosquito-borne diseases have resulted in serious crises associated with high mortality and left behind a huge socioeconomic burden. The chemical investigation of Lavandulacoronopifolia aerial parts extract using HPLC–MS/MS led to the tentative identification of 46 compounds belonging to phenolic acids, flavonoids and their glycosides, and biflavonoids. The extract displayed larvicidal activity against Culex pipiens larvae (LC50 = 29.08 µg/mL at 72 h). It significantly inhibited cytochrome P-450 monooxygenase (CYP450), acetylcholinesterase (AChE), and carboxylesterase (CarE) enzymes with the comparable pattern to the control group, which could explain the mode of larvae toxification. The extract also inhibited the biofilm formation of Pseudomonas aeruginosa by 17–38% at different Minimum Inhibitory Concentrations (MICs) (0.5–0.125 mg/mL) while the activity was doubled when combined with ciprofloxacin (ratio = 1:1 v:v). In conclusion, the wild plant, L.coronopifolia, can be considered a promising natural source against resistant bacteria and infectious carriers.

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Identification of FDA-Approved Drugs as Antivirulence Agents Targeting the pqs Quorum-Sensing System of Pseudomonas aeruginosa

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01296-18 ◽

2018 ◽

Vol 62 (11) ◽

Cited By ~ 27

Author(s):

Francesca D'Angelo ◽

Valerio Baldelli ◽

Nigel Halliday ◽

Paolo Pantalone ◽

Fabio Polticelli ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Biofilm Formation ◽

Antifungal Drugs ◽

Phenotypic Characterization ◽

Resistant Bacteria ◽

Gram Positive ◽

Active Inhibitor ◽

Content Type ◽

Approved Drugs

ABSTRACT The long-term use of antibiotics has led to the emergence of multidrug-resistant bacteria. A promising strategy to combat bacterial infections aims at hampering their adaptability to the host environment without affecting growth. In this context, the intercellular communication system quorum sensing (QS), which controls virulence factor production and biofilm formation in diverse human pathogens, is considered an ideal target. Here, we describe the identification of new inhibitors of the pqs QS system of the human pathogen Pseudomonas aeruginosa by screening a library of 1,600 U.S. Food and Drug Administration-approved drugs. Phenotypic characterization of ad hoc engineered strains and in silico molecular docking demonstrated that the antifungal drugs clotrimazole and miconazole, as well as an antibacterial compound active against Gram-positive pathogens, clofoctol, inhibit the pqs system, probably by targeting the transcriptional regulator PqsR. The most active inhibitor, clofoctol, specifically inhibited the expression of pqs-controlled virulence traits in P. aeruginosa, such as pyocyanin production, swarming motility, biofilm formation, and expression of genes involved in siderophore production. Moreover, clofoctol protected Galleria mellonella larvae from P. aeruginosa infection and inhibited the pqs QS system in P. aeruginosa isolates from cystic fibrosis patients. Notably, clofoctol is already approved for clinical treatment of pulmonary infections caused by Gram-positive bacterial pathogens; hence, this drug has considerable clinical potential as an antivirulence agent for the treatment of P. aeruginosa lung infections.

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

Evolution Medicine and Public Health ◽

10.1093/emph/eoaa026 ◽

2020 ◽

Vol 2020 (1) ◽

pp. 148-157 ◽

Cited By ~ 1

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.

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