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

Development and application of a bacteriophage cocktail for Shigella flexneri biofilm inhibition on the stainless steel surface

Food contamination and biofilm formation by Shigella in food processing facilities are major causes of acute gastrointestinal infection and mortality in humans. Bacteriophages (phages) are promising alternatives to antibiotics in controlling plankton and biofilms in food matrices. This study isolated two novel phages, S2_01 and S2_02, with lytic activity against various Shigella spp. From sewage samples. Transmission electron microscopy revealed that phages S2_01 and S2_02 belonged to the Caudovirales order. On characterizing their lytic ability, phage S2_01 initially exhibited relatively weak antibacterial activity, while phage S2_02 initially displayed rapid antibacterial activity after phage application. A combination of these phages in a 1:9 ratio was selected, as it has been suggested to elicit the most rapid and sustained lysis ability for up to 24 h. It demonstrated lytic activity against various foodborne pathogens, including six Shigella spp. The phage cocktail exhibited biofilm inhibition and disruption abilities of approximately 79.29% and 42.55%, respectively, after 24 h in a 96-well microplate. In addition, inhibition (up to 23.42%) and disruption (up to 19.89%) abilities were also observed on stainless steel surfaces, and plankton growth was also significantly suppressed. Therefore, the phage cocktail formulated in this study displays great potential as a biological control agent in improving food safety against biofilms and plankton.

The synergistic effect between phages and Ceftolozane/Tazobactam in Pseudomonas aeruginosa endotracheal tube biofilm

Although an increased effectiveness has been suggested when phages and antibiotics are combined, this approach has not been tested against a mature biofilm on an endotracheal tube (ETT) surface. This study evaluated the effect of short- and long-term combined phage-antibiotic therapy in a control of a mature biofilm on an ETT surface. Pseudomonas aeruginosa strains, including susceptible and resistant clinical samples, were used to develop the ETT biofilm. Biofilm was treated with 108PFU/mL of phage_2, phage_18 or 5 μg/mL of ceftolozane/tazobactam, alone or in combination with phages. The sequential combination of the two different phages and ceftolozane/tazobactam was also tested. Biofilm viability was assessed after short (2, 4, 24 h) and long-(48, 72 h) term treatment exposure using colony forming unit measurement. For long-term exposition, a new treatment shot was added every 24 h. In the sequential combination, the phage type was switched at 24 h of treatment. Regarding the susceptible strains, the treatments had limited antibiofilm effect after 2, 4 and 24 h. After 48 and 72 h, administering phages alone had no effect on biofilm viability, indicating the emergence of phage-resistant phenotypes. Nonetheless, the combined phage-antibiotic treatment reduced the biofilm viability in about 5-log, whilst antibiotic alone reduced in about 3-log. The sequential combination of phages and antibiotic reduced the biofilm viability in about 6-log. With respect to the resistant strains, no antibiofilm activity was observed regarding the treatment arms. The combination of phages and ceftolozane/tazobactam showed a synergism strain-dependent, being more apparent in susceptible strains.

Multi-drug resistant Pseudomonas aeruginosa isolation is an independent risk factor for recurrent hemoptysis after bronchial artery embolization in patients with idiopathic bronchiectasis: a retrospective cohort study

BACKGROUND

Currently, there is a lack of research on multi-drug resistant Pseudomonas aeruginosa (MDR-PA) isolation in bronchiectasis-related hemoptysis. The aim of this study to analyze the risk factors for recurrent hemoptysis following bronchial artery embolization (BAE) and compare the recurrent hemoptysis-free rates between MDR-PA, non-MDR-PA, and non-PA isolation.

METHODS

A retrospective study was performed of patients diagnosed with idiopathic bronchiectasis-related recurrent hemoptysis who underwent BAE at an university-affiliated hospital. Patients were categorized based on PA susceptibility tests into non-PA, non-MDR-PA, and MDR-PA groups. Univariate and multivariate Cox regression were conducted to identify independent risk factors for recurrent hemoptysis. The Kaplan-Meier curves was conducted to compare recurrent hemoptysis-free rates after BAE for non-PA, non-MDR-PA, and MDR-PA.

RESULTS

A total of 432 patients were included. 181 (41.90%) patients experienced recurrent hemoptysis during a median follow-up period of 25 months. MDR-PA isolation (adjusted hazard ratio (aHR) 2.120; 95% confidence interval (CI) [1.249, 3.597], p = 0.005) was identified as an independent risk factor for recurrent hemoptysis. Antibiotic treatment (aHR 0.666; 95% CI [0.476, 0.932], p = 0.018) reduced the risk of recurrent hemoptysis. The cumulative recurrent hemoptysis-free rates for non-PA, non-MDR-PA, and MDR-PA were as follows: at 3 months, 88.96%, 88.24%, and 75.86%, respectively; at 1 year, 73.13%, 69.10%, and 51.72%; and at 3 years, 61.91%, 51.69%, and 41.10% (p = 0.034).

CONCLUSION

MDR-PA isolation was an independent risk factor of recurrent hemoptysis post-BAE. Reducing the occurrence of MDR-PA may effectively decrease the recurrence rates of hemoptysis.

Optimizing Diagnosis and Management of Ventilator-Associated Pneumonia: A Systematic Evaluation of Biofilm Detection Methods and Bacterial Colonization on Endotracheal Tubes

Healthcare-associated infections, such as ventilator-associated pneumonia and biofilm formation on intubation cannulas, impose significant burdens on hospitals, affecting staffing, finances, and patient wellbeing, while also increasing the risk of patient mortality. We propose a research study aimed at exploring various methodologies for detecting these infections, discovered in the biofilm on medical devices, particularly tracheal cannulas, and understanding the role of each method in comprehending these infections from an etiological perspective. Our investigation also involves an analysis of the types of endotracheal tubes utilized in each case, the bacteria species identified, and strategies for combating biofilm-associated infections. The potential impact of our research is the substantial improvement of patient care through enhanced diagnosis and management of these infections.

An effective antibiofilm strategy based on bacteriophages armed with silver nanoparticles

The emerging antibiotic resistance in pathogenic bacteria is a key problem in modern medicine that has led to a search for novel therapeutic strategies. A potential approach for managing such bacteria involves the use of their natural killers, namely lytic bacteriophages. Another effective method involves the use of metal nanoparticles with antimicrobial properties. However, the use of lytic phages armed with nanoparticles as an effective antimicrobial strategy, particularly with respect to biofilms, remains unexplored. Here, we show that T7 phages armed with silver nanoparticles exhibit greater efficacy in terms of controlling bacterial biofilm, compared with phages or nanoparticles alone. We initially identified a novel silver nanoparticle-binding peptide, then constructed T7 phages that successfully displayed the peptide on the outer surface of the viral head. These recombinant, AgNP-binding phages could effectively eradicate bacterial biofilm, even when used at low concentrations. Additionally, when used at concentrations that could eradicate bacterial biofilm, T7 phages armed with silver nanoparticles were not toxic to eukaryotic cells. Our results show that the novel combination of lytic phages with phage-bound silver nanoparticles is an effective, synergistic and safe strategy for the treatment of bacterial biofilms.

The effect of phage-antibiotic combination strategy on multidrug-resistant Acinetobacter baumannii biofilms

Acinetobacter baumannii (A. baumannii) is considered a critical human pathogen due to multi-drug resistance and increased infections. As a result of the resistance of A. baumannii biofilms to antimicrobial agents, it is necessary to develop new biofilm control strategies. In the present study, we evaluated the efficacy of two previously isolated bacteriophage C2 phage, K3 phage and phage cocktail (C2 + K3 phage) as a therapeutic agent in combination with antibiotic (colistin) against biofilm of multidrug-resistant A. baumannii strains (n = 24). The effects of phage and antibiotics on mature biofilm were investigated simultaneously and sequentially in 24 and 48 h. The combination protocol was more effective than antibiotics alone in 54.16% of the strains in 24 h. The sequential application was more effective than the simultaneous protocol compared with the 24 h single applications. When the application of antibiotics and phages alone was compared with their combined administration in 48 h. The sequential and simultaneous applications were more effective than single applications in all strains except two. We observed that combination of phage and antibiotics could increase biofilm eradication and provides new insights into the use of bacteriophages and antibiotics in the treatment of biofilm-associated infections caused by antibiotic-resistant bacteria.

Antimicrobial materials for endotracheal tubes: A review on the last two decades of technological progress

Ventilator-associated pneumonia (VAP) is an unresolved problem in nosocomial settings, remaining consistently associated with a lack of treatment, high mortality, and prolonged hospital stay. The endotracheal tube (ETT) is the major culprit for VAP development owing to its early surface microbial colonization and biofilm formation by multiple pathogens, both critical events for VAP pathogenesis and relapses. To combat this matter, gradual research on antimicrobial ETT surface coating/modification approaches has been made. This review provides an overview of the relevance and implications of the ETT bioburden for VAP pathogenesis and how technological research on antimicrobial materials for ETTs has evolved. Firstly, certain main VAP attributes (definition/categorization; outcomes; economic impact) were outlined, highlighting the issues in defining/diagnosing VAP that often difficult VAP early- and late-onset differentiation, and that generate misinterpretations in VAP surveillance and discrepant outcomes. The central role of the ETT microbial colonization and subsequent biofilm formation as fundamental contributors to VAP pathogenesis was then underscored, in parallel with the uncovering of the polymicrobial ecosystem of VAP-related infections. Secondly, the latest technological developments (reported since 2002) on materials able to endow the ETT surface with active antimicrobial and/or passive antifouling properties were annotated, being further subject to critical scrutiny concerning their potentialities and/or constraints in reducing ETT bioburden and the risk of VAP while retaining/improving the safety of use. Taking those gaps/challenges into consideration, we discussed potential avenues that may assist upcoming advances in the field to tackle VAP rampant rates and improve patient care. STATEMENT OF SIGNIFICANCE: The use of the endotracheal tube (ETT) in patients requiring mechanical ventilation is associated with the development of ventilator-associated pneumonia (VAP). Its rapid surface colonization and biofilm formation are critical events for VAP pathogenesis and relapses. This review provides a comprehensive overview on the relevance/implications of the ETT biofilm in VAP, and on how research on antimicrobial ETT surface coating/modification technology has evolved over the last two decades. Despite significant technological advances, the limited number of gathered reports (46), highlights difficulty in overcoming certain hurdles associated with VAP (e.g., persistent colonization/biofilm formation; mechanical ventilation duration; hospital length of stay; VAP occurrence), which makes this an evolving, complex, and challenging matter. Challenges and opportunities in the field are discussed.

Natural Medicine a Promising Candidate in Combating Microbial Biofilm

Studies on biofilm-related infections are gaining prominence owing to their involvement in most clinical infections and seriously threatening global public health. A biofilm is a natural form of bacterial growth ubiquitous in ecological niches, considered to be a generic survival mechanism adopted by both pathogenic and non-pathogenic microorganisms and entailing heterogeneous cell development within the matrix. In the ecological niche, quorum sensing is a communication channel that is crucial to developing biofilms. Biofilm formation leads to increased resistance to unfavourable ecological effects, comprising resistance to antibiotics and antimicrobial agents. Biofilms are frequently combated with modern conventional medicines such as antibiotics, but at present, they are considered inadequate for the treatment of multi-drug resistance; therefore, it is vital to discover some new antimicrobial agents that can prevent the production and growth of biofilm, in addition to minimizing the side effects of such therapies. In the search for some alternative and safe therapies, natural plant-derived phytomedicines are gaining popularity among the research community. Phytomedicines are natural agents derived from natural plants. These plant-derived agents may include flavonoids, terpenoids, lectins, alkaloids, polypeptides, polyacetylenes, phenolics, and essential oils. Since they are natural agents, they cause minimal side effects, so could be administered with dose flexibility. It is vital to discover some new antimicrobial agents that can control the production and growth of biofilms. This review summarizes and analyzes the efficacy characteristics and corresponding mechanisms of natural-product-based antibiofilm agents, i.e., phytochemicals, biosurfactants, antimicrobial peptides, and their sources, along with their mechanism, quorum sensing signalling pathways, disrupting extracellular matrix adhesion. The review also provides some other strategies to inhibit biofilm-related illness. The prepared list of newly discovered natural antibiofilm agents could help in devising novel strategies for biofilm-associated infections.

Characterization and anti-biofilm activity of bacteriophages against urinary tract Enterococcus faecalis isolates

Strong biofilm-forming Enterococcus feacalis urinary tract pathogens (n = 35) were used to determine the lytic spectrum of six bacteriophages isolated from sewage samples. Only 17 Enterococcus feacalis isolates gave lytic zones with the tested bacteriophages from which five isolates were susceptible to all of them. The isolated enterococcal phages are characterized by wide range of thermal (30–90 °C) and pH (3–10) stability. They belong to order Caudovirales, from which four bacteriophages (EPA, EPB, EPD, EPF) belong to family Myoviridae and two (EPC, EPE) belong to family Siphoviridae. In addition, they have promising antibiofilm activity against the tested strong-forming biofilm E. faecalis isolates. The enterococcal phages reduced the formed and preformed biofilms to a range of 38.02–45.7% and 71.0–80.0%, respectively, as compared to the control. The same promising activities were obtained on studying the anti-adherent effect of the tested bacteriophages on the adherence of bacterial cells to the surface of urinary catheter segments. They reduced the number of adherent cells to a range of 30.8–43.8% and eradicated the pre-adherent cells to a range of 48.2–71.1%, as compared to the control. Overall, the obtained promising antibiofilm activity makes these phages good candidates for application in preventing and treating biofilm associated Enterococcus faecalis infections.

Assessment of Phage-Mediated Inhibition and Removal of Multidrug-Resistant Pseudomonas aeruginosa Biofilm on Medical Implants

Purpose

Despite the growing interest in bacteriophage (phage) usage for the prevention, control, and removal of bacterial biofilms, few scientific data exist on phage applications on medical implant surfaces, while none exists on multiple implants. In this study, we aimed to isolate, biophysically characterize and assess phages as potential antibiofilm agents to inhibit and remove multidrug-resistant (MDR) Pseudomonas aeruginosa biofilm on catheter and endotracheal tube surfaces.

Methods

The well-identified stored clinical isolates (n = 7) of MDR P. aeruginosa were obtained from Jimma Medical Center. Specific phages were isolated and characterized based on standard protocols. The phages were tested for their antibiofilm effects in preventing colonization and removing preformed biofilms of MDR P. aeruginosa, following phage coating and treatment of catheter and endotracheal tube segments.

Results

Two P. aeruginosa-specific phages (ΦJHS-PA1139 and ΦSMK-PA1139) were isolated from JMC compound sewage sources. The phages were biophysically characterized as being thermally stable up to 40°C and viable between pH 4.0 and 11.0. The two phages tested against clinical MDR strains of P. aeruginosa showed broad host ranges but not on other tested bacterial species. Both phages reduced MDR bacterial biofilms during the screening step. The phage-coated segments showed 1.2 log10 up to 3.2 log10 inhibition relative to non-coated segments following 6 h coating of segments prior to microbial load exposure. In both phages, 6 h treatment of the segments with 106 PFU/mL yielded 1.0 log10 up to 1.6 log10 reductions for ΦJHS and 1.6 log10 up to 2.4 log10 reductions for ΦSMK.

Conclusion

Our results suggest that phages have great potential to serve the dual purpose as surface coating agents for preventing MDR bacterial colonization in medical implants and as biofilm removal agents in implant-associated infections.

Phage therapy of wound-associated infections

Phages are viruses which can specifically infect bacteria, resulting in their destruction. Bacterial infections are a common complication of wound healing, and experimental evidence from animal models demonstrates promising potential for phage-dependent eradication of wound-associated infections. The studies discussed suggest that phage therapy may be an effective treatment, with important advantages over some current antibacterial treatments. Phage cocktails, as well as co-administration of phages and antibiotics, have been reported to minimise bacterial resistance. Further, phage-antibiotic synergism has been reported in some studies. The ideal dose of phages is still subject to debate, with evidence for both high and low doses to yield therapeutic effects. Novel delivery methods, such as hydrogels, are being explored for their advantages in topical wound healing. There are more and more Good Manufacturing Practice facilities dedicated to manufacturing phage products and phage therapy units across the world, showing the changing perception of phages which is occurring. However, further research is needed to secure the place of phages in modern medicine, with some scientists calling upon the World Health Organisation to help promote phage therapy.

Antimicrobial Coating: Tracheal Tube Application

Ventilator-associated pneumonia (VAP) is a common and serious nosocomial infection in mechanically ventilated patients, increasing mortality, prolonging the patient length of stay, and increasing costs. In recent years, extensive studies on ventilator-associated pneumonia have shown that tracheal intubation plays an essential role in the pathogenesis of VAP, with the primary mechanism being the rapid colonization of the tracheal intubation surface by microbiota. Antibiotics do not combat microbial airway colonization, and antimicrobial coating materials offer new ideas to solve this problem. This paper reviews the current research progress on the role of endotracheal tube (ET) biofilms in the pathogenesis of VAP and antimicrobial coating materials.

Pathogenesis of the Pseudomonas aeruginosa Biofilm: A Review

Pseudomonas aeruginosa is associated with several human infections, mainly related to healthcare services. In the hospital, it is associated with resistance to several antibiotics, which poses a great challenge to therapy. However, one of the biggest challenges in treating P. aeruginosa infections is that related to biofilms. The complex structure of the P. aeruginosa biofilm contributes an additional factor to the pathogenicity of this microorganism, leading to therapeutic failure, in addition to escape from the immune system, and generating chronic infections that are difficult to eradicate. In this review, we address several molecular aspects of the pathogenicity of P. aeruginosa biofilms.

Lactobacillus johnsonii 3-1 and Lactobacillus crispatus 7-4 promote the growth performance and ileum development and participate in lipid metabolism of broilers

Long-term use of antibiotic growth promoter (AGP) in animal production is the main cause of antimicrobial resistance of pathogenic bacteria. Therefore, seeking alternatives to AGP is crucial for animal husbandry. Among all AGP alternatives, probiotics are promising candidates. In this study, two strains of lactic acid bacteria, L. johnsonii 3-1 and L. crispatus 7-4, were isolated from the feces of wild Gallus gallus, which exhibited obvious anti-pathogenic activity and improved the growth performance of broilers. Furthermore, we found that these two strains participated in the lipid metabolism of broilers by reducing the content of TC and TG in ileal epithelial cells and up-regulating the liver AMPKα/PPARα/CPT-1 pathway, which affects abdominal fat deposition. In summary, L. johnsonii 3-1 and L. crispatus 7-4 have the potential to be used as AGP substitutes and participate in the lipid metabolism of broilers to reduce abdominal fat deposition. Importantly, our study reveals for the first time that L. crispatus participates in liver lipid metabolism to reduce abdominal fat deposition in broilers.

Bacterial Biofilm Destruction: A Focused Review On The Recent Use of Phage-Based Strategies With Other Antibiofilm Agents

Biofilms are bacterial communities that live in association with biotic or abiotic surfaces and enclosed in an extracellular polymeric substance. Their formation on both biotic and abiotic surfaces, including human tissue and medical device surfaces, pose a major threat causing chronic infections. In addition, current antibiotics and antiseptic agents have shown limited ability to completely remove biofilms. In this review, the authors provide an overview on the formation of bacterial biofilms and its characteristics, burden and evolution with phages. Moreover, the most recent possible use of phages and phage-derived enzymes to combat bacteria in biofilm structures is elucidated. From the emerging results, it can be concluded that despite successful use of phages and phage-derived products in destroying biofilms, they are mostly not adequate to eradicate all bacterial cells. Nevertheless, a combined therapy with the use of phages and/or phage-derived products with other antimicrobial agents including antibiotics, nanoparticles, and antimicrobial peptides may be effective approaches to remove biofilms from medical device surfaces and to treat their associated infections in humans.

New Insights on Biofilm Antimicrobial Strategies

Over the last few decades, the study of microbial biofilms has been gaining interest among the scientific community [...].