A phage cocktail in controlling phage resistance development in multidrug resistant Aeromonas hydrophila with great therapeutic potential

Abstract Background Multidrug-resistant (MDR) Pseudomonas aeruginosa infections are increasing in prevalence and cause significant mortality. The MexAB-OprM efflux system confers resistance to a wide range of drugs, including β-lactams, fluoroquinolones, tetracyclines, and macrolides. Obligately lytic bacteriophages (phages) are viruses that infect and kill bacteria. Phage therapy has been suggested as an alternative treatment option in combination with traditional antibiotics. The objective of this study was to determine the ability of a phage cocktail in combination with ciprofloxacin (CIP) to improve bacterial killing and/or prevent the emergence of phage resistance in MDR P. aeruginosa. Methods Initial bacterial susceptibility to phage was evaluated with three newly isolated phages (phages EM, LL, and A6) against ten clinical MDR P. aeruginosa isolates. Theoretical multiplicity of infection (tMOI) optimization was performed with two phages with the broadest initial susceptibility (tMOI: 1.0 chosen for further analysis). A preliminary evaluation was performed with P. aeruginosa R9316 (carbapenem-resistant clinical strain with MexAB-OprM overexpression, as determined previously by quantitative real-time PCR). Synergy for phage cocktail combinations (≥ 2-log10 CFU/mL kill compared to most effective single agent at 24 h), bactericidal activity for all samples (≥ 3-log10 CFU/mL reduction at 24 h compared to starting inoculum), and phage resistance development were evaluated in time kill analyses (TKA). Results R9316 is a MDR P. aeruginosa isolate with a CIP MIC of 2 mg/L. Phage cocktails as monotherapy had little impact on bacterial eradication (reduction: 1.19 log10 CFU/mL). However, the addition of CIP to phage cocktails of EM and LL phages led to synergistic and bactericidal effects (reduction: 3.92 log10 CFU/mL). Furthermore, phage resistance was observed in the phage monotherapy regimens. Whereas the addition of CIP was shown to prevent the emergence of phage resistance in some regimens. Conclusion Our results show synergistic activity and prevention of phage resistance with phage cocktail-antibiotic combinations against MDR P. aeruginosa. Further research is needed to determine the impact of phage cocktail therapy on additional strains and clinical outcomes. Disclosures Michael J. Rybak, PharmD, MPH, PhD, Paratek Pharmaceuticals (Research Grant or Support)

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Pseudomonas aeruginosa PAO 1 In Vitro Time–Kill Kinetics Using Single Phages and Phage Formulations—Modulating Death, Adaptation, and Resistance

Antibiotics ◽

10.3390/antibiotics10070877 ◽

2021 ◽

Vol 10 (7) ◽

pp. 877

Author(s):

Ana Mafalda Pinto ◽

Alberta Faustino ◽

Lorenzo M. Pastrana ◽

Manuel Bañobre-López ◽

Sanna Sillankorva

Keyword(s):

Pseudomonas Aeruginosa ◽

Phage Therapy ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Chronic Infections ◽

Swarming Motility ◽

Resistance Development ◽

Healthcare Settings ◽

Time Kill

Pseudomonas aeruginosa is responsible for nosocomial and chronic infections in healthcare settings. The major challenge in treating P. aeruginosa-related diseases is its remarkable capacity for antibiotic resistance development. Bacteriophage (phage) therapy is regarded as a possible alternative that has, for years, attracted attention for fighting multidrug-resistant infections. In this work, we characterized five phages showing different lytic spectrums towards clinical isolates. Two of these phages were isolated from the Russian Microgen Sextaphage formulation and belong to the Phikmvviruses, while three Pbunaviruses were isolated from sewage. Different phage formulations for the treatment of P. aeruginosa PAO1 resulted in diversified time–kill outcomes. The best result was obtained with a formulation with all phages, prompting a lower frequency of resistant variants and considerable alterations in cell motility, resulting in a loss of 73.7% in swimming motility and a 79% change in swarming motility. These alterations diminished the virulence of the phage-resisting phenotypes but promoted their growth since most became insensitive to a single or even all phages. However, not all combinations drove to enhanced cell killings due to the competition and loss of receptors. This study highlights that more caution is needed when developing cocktail formulations to maximize phage therapy efficacy. Selecting phages for formulations should consider the emergence of phage-resistant bacteria and whether the formulations are intended for short-term or extended antibacterial application.

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Bacteriophage Cocktail-Mediated Inhibition of Pseudomonas aeruginosa Biofilm on Endotracheal Tube Surface

Antibiotics ◽

10.3390/antibiotics10010078 ◽

2021 ◽

Vol 10 (1) ◽

pp. 78

Author(s):

Viviane C. Oliveira ◽

Ana P. Macedo ◽

Luís D. R. Melo ◽

Sílvio B. Santos ◽

Paula R. S. Hermann ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Endotracheal Tube ◽

Metabolic Activity ◽

Bacterial Colonization ◽

Multidrug Resistant ◽

Scientific Data ◽

Tube Surface ◽

Screening Assay ◽

Biofilm Growth ◽

Phage Cocktail

Although different strategies to control biofilm formation on endotracheal tubes have been proposed, there are scarce scientific data on applying phages for both removing and preventing Pseudomonas aeruginosa biofilms on the device surface. Here, the anti-biofilm capacity of five bacteriophages was evaluated by a high content screening assay. We observed that biofilms were significantly reduced after phage treatment, especially in multidrug-resistant strains. Considering the anti-biofilm screens, two phages were selected as cocktail components, and the cocktail’s ability to prevent colonization of the endotracheal tube surface was tested in a dynamic biofilm model. Phage-coated tubes were challenged with different P. aeruginosa strains. The biofilm growth was monitored from 24 to 168 h by colony forming unit counting, metabolic activity assessment, and biofilm morphology observation. The phage cocktail promoted differences of bacterial colonization; nonetheless, the action was strain dependent. Phage cocktail coating did not promote substantial changes in metabolic activity. Scanning electron microscopy revealed a higher concentration of biofilm cells in control, while tower-like structures could be observed on phage cocktail-coated tubes. These results demonstrate that with the development of new coating strategies, phage therapy has potential in controlling the endotracheal tube-associated biofilm.

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Characterization of Anti-Bacterial Effect of the Two New Phages against Uropathogenic Escherichia coli

Viruses ◽

10.3390/v13071348 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1348

Author(s):

Lívia Slobodníková ◽

Barbora Markusková ◽

Michal Kajsík ◽

Michal Andrezál ◽

Marek Straka ◽

...

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Urinary Tract Infections ◽

Therapeutic Potential ◽

Medical Intervention ◽

Uropathogenic Escherichia Coli ◽

E Coli ◽

Phage Cocktail ◽

Causative Agents ◽

Tract Infections

Urinary tract infections (UTIs) are among the events that most frequently need medical intervention. Uropathogenic Escherichia coli are frequently their causative agents and the infections are sometimes complicated by the presence of polyresistant nosocomial strains. Phage therapy is a tool that has good prospects for the treatment of these infections. In the present study, we isolated and characterized two bacteriophages with broad host specificity against a panel of local uropathogenic E. coli strains and combined them into a phage cocktail. According to genome sequencing, these phages were closely related and belonged to the Tequatrovirus genus. The newly isolated phages showed very good activity on a panel of local clinical E. coli strains from urinary tract infections. In the form of a two-phage cocktail, they were active on E. coli strains belonging to phylogroups B2 and D, with relatively lower activity in B1 and no response in phylogroup A. Our study is a preliminary step toward the establishment of a national phage bank containing local, well-characterized phages with therapeutic potential for patients in Slovakia.

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Susceptibility of the Candida haemulonii Complex to Echinocandins: Focus on Both Planktonic and Biofilm Life Styles and a Literature Review

Journal of Fungi ◽

10.3390/jof6040201 ◽

2020 ◽

Vol 6 (4) ◽

pp. 201

Author(s):

Lívia S. Ramos ◽

Laura N. Silva ◽

Marta H. Branquinha ◽

André L. S. Santos

Keyword(s):

Literature Review ◽

Therapeutic Potential ◽

Multidrug Resistant ◽

Antifungal Drugs ◽

Clinical Isolates ◽

Published Data ◽

Life Styles ◽

Fungal Isolates ◽

Candida Haemulonii ◽

Almost All

Candida haemulonii complex (C. haemulonii, C. duobushaemulonii and C. haemulonii var. vulnera) is well-known for its resistance profile to different available antifungal drugs. Although echinocandins are the most effective class of antifungal compounds against the C. haemulonii species complex, clinical isolates resistant to caspofungin, micafungin and anidulafungin have already been reported. In this work, we present a literature review regarding the effects of echinocandins on this emergent fungal complex. Published data has revealed that micafungin and anidulafungin were more effective than caspofungin against the species forming the C. haemulonii complex. Subsequently, we investigated the susceptibilities of both planktonic and biofilm forms of 12 Brazilian clinical isolates of the C. haemulonii complex towards caspofungin and micafungin (anidulafungin was unavailable). The planktonic cells of all the fungal isolates were susceptible to both of the test echinocandins. Interestingly, echinocandins caused a significant reduction in the biofilm metabolic activity (viability) of almost all fungal isolates (11/12, 91.7%). Generally, the biofilm biomasses were also affected (reduction range 20–60%) upon exposure to caspofungin and micafungin. This is the first report of the anti-biofilm action of echinocandins against the multidrug-resistant opportunistic pathogens comprising the C. haemulonii complex, and unveils the therapeutic potential of these compounds.

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Isolation and Characterization of Two Lytic Bacteriophages Infecting a Multi-Drug Resistant Salmonella Typhimurium and Their Efficacy to Combat Salmonellosis in Ready-to-Use Foods

Microorganisms ◽

10.3390/microorganisms9020423 ◽

2021 ◽

Vol 9 (2) ◽

pp. 423

Author(s):

Ahmed Esmael ◽

Ehab Azab ◽

Adil A. Gobouri ◽

Mohamed A. Nasr-Eldin ◽

Mahmoud M. A. Moustafa ◽

...

Keyword(s):

Salmonella Typhimurium ◽

Multidrug Resistant ◽

Viable Count ◽

Food Storage ◽

Chicken Breast ◽

Whole Genome Analysis ◽

Isolation And Characterization ◽

Phage Cocktail ◽

Global Threat

Foodborne salmonellosis is a global threat to public health. In the current study, we describe the isolation and characterization of two broad-spectrum, lytic Salmonella phages: SPHG1 and SPHG3 infecting a multidrug-resistant Salmonella Typhimurium EG.SmT3. Electron microscopy and whole genome analysis identified SPHG1 as a Myovirus, while SPHG3 as a new member of the genus “Kuttervirus” within the family Ackermannviridae. SPHG1 and SPHG3 had a lysis time of 60 min. with burst sizes of 104 and 138 PFU/cell, respectively. The two phages were robust at variable temperatures and pH ranges that match the corresponding values of most of the food storage and processing conditions. A phage cocktail containing the two phages was stable in the tested food articles for up to 48 h. The application of the phage cocktail at MOIs of 1000 or 100 resulted in a significant reduction in the viable count of S. Typhimurium by 4.2 log10/sample in milk, water, and on chicken breast. Additionally, the phage cocktail showed a prospective ability to eradicate and reduce the biofilm that formed by S. Typhimurium EG.SmT3. A phage cocktail of SPHG1 and SPHG3 is considered as a promising candidate as a biocontrol agent against foodborne salmonellosis due to its broad host ranges, highly lytic activities, and the absence of any virulence or lysogeny-related genes in their genomes.

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Therapeutic Potential of Green Synthesized Metallic Nanoparticles against Staphylococcus aureus

Current Drug Research Reviews ◽

10.2174/2589977513666210226123920 ◽

2021 ◽

Vol 13 ◽

Author(s):

Meron Moges Tsegaye ◽

Garima Chouhan ◽

Molla Fentie ◽

Priya Tyagi ◽

Parma Nand

Keyword(s):

Staphylococcus Aureus ◽

Metallic Nanoparticles ◽

Therapeutic Potential ◽

Multidrug Resistant ◽

Health Condition ◽

World Health ◽

Therapeutic Modality ◽

Effective Control ◽

Bacterial Strains ◽

Synthesis Of Nanoparticles

Background: The recent treatment challenges posed by the widespread emergence of pathogenic Multidrug‐Resistant (MDR) bacterial strains are a cause of huge health troubles worldwide. Infections caused by MDR organisms are associated with longer period of hospitalization, increased mortality, and inflated healthcare costs. Staphylococcus aureus is one of these MDR organisms identified as an urgent threat to human health by the World Health Organization. Infections caused by S. aureus may range from simple cutaneous infestations to life threatening bacteremia. S. aureus infections get easily escalated in severely ill, hospitalized and or immunocompromised patients with incapacitated immune system. Also, in HIV-positive patients S. aureus ranks amongst one of the most common comorbidities where it can further worsen a patient’s health condition. At present anti-staphylococcal therapy is reliant typically on chemotherapeutics that are gathering resistance and pose unfavorable side-effects. Thus, newer drugs are required that can bridge these shortcomings and aid effective control against S. aureus. Objective: In this review, we summarize drug resistance exhibited by S. aureus and lacunae in current anti-staphylococcal therapy, nanoparticles as an alternative therapeutic modality. The focus lays on various green synthesized nanoparticles, their mode of action and application as potent antibacterial compounds against S. aureus. Conclusion: Use of nanoparticles as anti-bacterial drugs has gained momentum in recent past and green synthesized nanoparticles, which involves microorganisms and plants or their byproducts for synthesis of nanoparticles offer a potent, as well as environment friendly solution in warfare against MDR bacte.

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In VitroandIn VivoAntimicrobial Activities of Gallium Nitrate against Multidrug-Resistant Acinetobacter baumannii

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01519-12 ◽

2012 ◽

Vol 56 (11) ◽

pp. 5961-5970 ◽

Cited By ~ 72

Author(s):

Luísa C. S. Antunes ◽

Francesco Imperi ◽

Fabrizia Minandri ◽

Paolo Visca

Keyword(s):

Human Serum ◽

Acinetobacter Baumannii ◽

Galleria Mellonella ◽

Therapeutic Potential ◽

Survival Rates ◽

Bloodstream Infections ◽

Multidrug Resistant ◽

Gallium Nitrate ◽

Content Type ◽

Bacterial Physiology

ABSTRACTMultidrug-resistantAcinetobacter baumanniiposes a tremendous challenge to traditional antibiotic therapy. Due to the crucial role of iron in bacterial physiology and pathogenicity, we investigated iron metabolism as a possible target for anti-A. baumanniichemotherapy using gallium as an iron mimetic. Due to chemical similarity, gallium competes with iron for binding to several redox enzymes, thereby interfering with a number of essential biological reactions. We found that Ga(NO3)3, the active component of an FDA-approved drug (Ganite), inhibits the growth of a collection of 58A. baumanniistrains in both chemically defined medium and human serum, at concentrations ranging from 2 to 80 μM and from 4 to 64 μM, respectively. Ga(NO3)3delayed the entry ofA. baumanniiinto the exponential phase and drastically reduced bacterial growth rates. Ga(NO3)3activity was strongly dependent on iron availability in the culture medium, though the mechanism of growth inhibition was independent of dysregulation of gene expression controlled by the ferric uptake regulator Fur. Ga(NO3)3also protectedGalleria mellonellalarvae from lethalA. baumanniiinfection, with survival rates of ≥75%. At therapeutic concentrations for humans (28 μM plasma levels), Ga(NO3)3inhibited the growth in human serum of 76% of the multidrug-resistantA. baumanniiisolates tested by ≥90%, raising expectations on the therapeutic potential of gallium for the treatment ofA. baumanniibloodstream infections. Ga(NO3)3also showed strong synergism with colistin, suggesting that a colistin-gallium combination holds promise as a last-resort therapy for infections caused by pan-resistantA. baumannii.

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