Bacteriophage-Mediated Control of Biofilm: A Promising New Dawn for the Future

Isolation, characterization, and application of a novel Vibrio parahaemolyticus bacteriophage from retail shrimp in Sarawak, Malaysia

Shrimp farming, a highly profitable sector in global aquaculture, has seen remarkable growth in recent years. This increasing demand and the expansion of farming operations, including in Sarawak, Malaysia, highlight the sector's potential. However, the industry faces significant challenges, particularly the prevalence of vibriosis, a bacterial infection caused by Vibrio species. Contamination of food products has also increased the risk of vibriosis in humans. The widespread use of antibiotics to combat this disease has led to the rapid emergence of antimicrobial resistance (AMR) bacteria. This study specifically focuses on the isolation and characterization of phage EniLVP02, a novel bacteriophage with the potential to combat V. parahaemolyticus infections. EniLVP02 was successfully isolated from shrimp purchased at a retail market and exhibited strong lytic activity against V. parahaemolyticus strains. Structural analysis categorized EniLVP02 within the Straboviridae family, belonging to the class Caudoviricetes. The phage displayed a narrow host range and lytic nature only towards V. parahaemolyticus strains isolated from the Telaga Air shrimp farm. Phage EniLVP02 exhibited long latent period of 120 min and large burst size of 144 phages per infected cells. Stability studies revealed EniLVP02's resilience across various pH (pH 4.0-9.0) and temperature (28 °C-65 °C) conditions, particularly at physiological temperatures. Comparative genome analyses indicated its distinct evolutionary relationship and low homology with other Vibriophages, suggesting its novelty. EniLVP02 demonstrated significant potential in biofilm prevention and destruction, with absorbance (OD600 nm) reduction from 0.592 ± 0.055 to 0.204± 0.016 and from 0.843± 0.003 to 0.174± 0.026 respectively. Moreover, in the treatment of V. parahaemolyticus-contaminated shrimp meat, EniLVP02 effectively inhibit bacterial concentrations by 75.2 % at room temperature and 16.2 % at 4 °C after 24 h. Genomic sequencing revealed low similarity between EniLVP02 with other phages, suggesting its novelty. Importantly, the absence of lysogeny-related, antibiotic resistance, and virulence genes in its genome supports EniLVP02's safety for therapeutic use. This study underscores the importance of exploring phages from retail food products for therapeutic applications and highlights the promising attributes of phage EniLVP02 in combating V. parahaemolyticus infections in aquaculture. Further investigations on its compatibility with other phages and application in diverse food matrices are warranted to assess its full potential.

Pulsed Blue Light and Phage Therapy: A Novel Synergistic Bactericide

Background: Antibiotic-resistant Pseudomonas aeruginosa (P. aeruginosa) strains are an increasing cause of morbidity and mortality. Pulsed blue light (PBL) enhances porphyrin-induced reactive oxygen species and has been clinically shown to be harmless to the skin at low doses. Bacteriophages, viruses that infect bacteria, offer a promising non-antibiotic bactericidal approach. This study investigates the potential synergism between low-dose PBL and phage therapy against P. aeruginosa in planktonic cultures and preformed biofilms. Methods: We conducted a factorial dose-response in vitro study combining P. aeruginosa-specific phages with PBL (457 nm, 33 kHz) on both PA14 and multidrug-resistant PATZ2 strains. After excluding direct PBL effects on phage titer or activity, we assessed effectiveness on planktonic cultures using growth curve analysis (via growth_curve_outcomes, a newly developed, Python-based tool available on GitHub) , CFU, and PFU. Biofilm efficacy was evaluated using CFU post-sonication, crystal violet staining, and live/dead staining with confocal microscopy. Finally, we assessed reactive oxygen species (ROS) as a potential mechanism using the nitro blue tetrazolium reduction assay. ANOVA or Kruskal-Wallis tests with post hoc Tukey or Conover-Iman tests were used for comparisons (n = 5 biological replicates and technical triplicates). Results: The bacterial growth lag phase was significantly extended for phage alone or PBL alone, with a synergistic effect of up to 144% (p < 0.001 for all), achieving a 9 log CFU/mL reduction at 24 h (p < 0.001). In preformed biofilms, synergistic combinations significantly reduced biofilm biomass and bacterial viability (% Live, median (IQR): Control 80%; Phage 40%; PBL 25%; PBL&Phage 15%, p < 0.001). Mechanistically, PBL triggered transient ROS in planktonic cultures, amplified by phage co-treatment, while a biphasic ROS pattern in biofilms reflected time-dependent synergy. Conclusions: Phage therapy combined with PBL demonstrates a synergistic bactericidal effect against P. aeruginosa in both planktonic cultures and biofilms. Given the strong safety profile of PBL and phages, this approach may lead to a novel, antibiotic-complementary, safe treatment modality for patients suffering from difficult-to-treat antibiotic-resistant infections and biofilm-associated infections.

Application of phage-derived enzymes for enhancing food safety

Foodborne pathogens such as Salmonella, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus present significant public health threats, causing widespread illness and economic loss. Contaminated food is responsible for an estimated 600 million illnesses and 420,000 deaths annually, with low- and middle-income countries facing losses of approximately $110 billion each year. Traditional methods to ensure food safety, including antimicrobials and preservatives, can contribute to the development of antimicrobial-resistant bacteria, highlighting the need for alternative strategies. Bacteriophages are gaining renewed attention as promising alternatives to conventional antibiotics due to their specifically target bacteria and their lower potential for causing adverse effects. However, their practical application is limited by challenges such as narrow host ranges, the emergence of phage-resistant bacteria, and stability issues. Recent research has shifted focus towards phage-derived enzymes, including endolysins, depolymerases, holins, and spanins, which are involved in the phage lytic cycle. These enzymes, as potential approaches to food safety, have demonstrated significant efficacy in targeting and lysing bacterial pathogens, making them suitable for controlling foodborne pathogens and preventing foodborne illnesses. Phage-derived enzymes also show promise in controlling biofilms and enhancing antimicrobial activity when combined with other antimicrobials. Therefore, this review emphasizes recent advancements in the use of the phage-derived enzymes for food safety, addresses their limitations, and suggests strategies to enhance their effectiveness in food processing and storage environments.

Therapeutic potential of novel phages with antibiotic combinations against ESBL-producing and carbapenem-resistant Escherichia Coli

OBJECTIVES

The emergence of extended-spectrum β-lactamase (ESBL)-producing E. coli and carbapenem-resistant E. coli (CREC) is a significant global health challenge. This study focuses on isolating and characterizing two novel phages, EC.W1-9 and EC.W15-4, and investigating their efficacy with antibiotics against these resistant E. coli.

METHODS

In vivo experiments were conducted using BALB/c mice, and E.coli isolates were collected, cultured, and evaluated for antibiotic susceptibility. Phages were isolated from hospital sewage and prepared to infect the E. coli.

RESULTS

The isolated phages, EC.W1-9 and EC.W15-4, belonged to the Podoviridae and Straboviridae families, and lack integrase or toxin-coding genes, indicating safety for therapeutic use. The combination of these phages significently enhanced their lytic ability, lysing 61.7% of 60 E. coli isolates, compared to 41.6%-55% lysis by individual phages. Furthermore, the phage combination demonstrated 100% susceptibility against different E. coli sequence types, including ST73, ST648, ST2311, ST405, ST7962, ST131, ST13003, and ST167. Additionally, synergy between antibiotics and phage combinations improved susceptibility rates to 73.3% for ESBL producers and 54% for CREC. The combined treatment of isolated phages and antibiotics significantly increased survival rates in BALB/c mice exposed to resistant STs of E.coli, including ST131, ST648, and ST410. Survival rates against ST131 increased by approximately 75% and 50% compared to treatment individual phages. Combined treatment with two phages and antibiotics resulted in 75-100% survival against E. coli ST410 and 100% survival against ST648 CONCLUSIONS: This study highlights the therapeutic importance of phage and phage-antibiotic combinations in combating ESBL-producing E. coli and CREC isolates.

Facing Foodborne Pathogen Biofilms with Green Antimicrobial Agents: One Health Approach

Food safety is a significant global and local concern due to the threat of foodborne pathogens to public health and food security. Bacterial biofilms are communities of bacteria adhered to surfaces and represent a persistent contamination source in food environments. Their resistance to conventional antimicrobials exacerbates the challenge of eradication, driving the search for alternative strategies to control biofilms. Unconventional or "green" antimicrobial agents have emerged as promising solutions due to their sustainability and effectiveness. These agents include bacteriophages, phage-derived enzymes, plant extracts, and combinations of natural antimicrobials, which offer novel mechanisms for targeting biofilms. This approach aligns with the "One Health" concept, which underscores the interconnectedness of human, animal, and environmental health and advocates for integrated strategies to address public health challenges. Employing unconventional antimicrobial agents to manage bacterial biofilms can enhance food safety, protect public health, and reduce environmental impacts by decreasing reliance on conventional antimicrobials and mitigating antimicrobial resistance. This review explores the use of unconventional antimicrobials to combat foodborne pathogen biofilms, highlighting their mechanisms of action, antibiofilm activities, and the challenges associated with their application in food safety. By addressing these issues from a "One Health" perspective, we aim to demonstrate how such strategies can promote sustainable food safety, improve public health outcomes, and support environmental health, ultimately fostering a more integrated approach to combating foodborne pathogen biofilms.

Lytic activity, stability, biofilm disruption capabilities, and genomic characterization of two bacteriophages active against respiratory MRSA

AIMS

This study aimed to characterize bacteriophages for potential therapeutic use against Staphylococcus aureus, focusing on clinical respiratory isolates of methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) strains. Specifically, it sought to evaluate phage lytic activity, host range, stability, biofilm disruption capabilities, and overall safety for therapeutic use.

METHODS AND RESULTS

Novel phages, Koomba kaat 1 and Biyabeda mokiny 1, were identified and characterized using microbiological assays and bioinformatics. They exhibited lytic activity against clinical MSSA and MRSA isolates, disrupted biofilms from airway isolates, remained stable for at least one year in storage, and could be aerosolized without significant reductions in activity. Bioinformatic tools were used to assess safety, lifecycle, virulence, and prophage contamination when grown using their original isolation host. Receptor binding proteins within their genomes were also predicted, providing insight into their mechanisms of action. Both phages demonstrated strong efficacy against the clinical isolates tested and demonstrated robust stability under storage and delivery conditions.

CONCLUSIONS

Koomba kaat 1 and Biyabeda mokiny 1 are promising candidates for phage therapy. Their efficacy against clinical S. aureus isolates, ability to break down biofilm, and stability for airway implementation, positions them as valuable tools for addressing persistent airway infections caused by S. aureus.

Insights into biofilm-mediated mechanisms driving last-resort antibiotic resistance in clinical ESKAPE pathogens

The rise of antibiotic-resistant bacteria poses a grave threat to global health, with the ESKAPE pathogens, which comprise Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. being among the most notorious. The World Health Organization has reserved a group of last-resort antibiotics for treating multidrug-resistant bacterial infections, including those caused by ESKAPE pathogens. This situation calls for a comprehensive understanding of the resistance mechanisms as it threatens public health and hinder progress toward the Sustainable Development Goal (SDG) 3: Good Health and Well-being. The present article reviews resistance mechanisms, focusing on emerging resistance mutations in multidrug-resistant ESKAPE pathogens, particularly against last-resort antibiotics, and describes the role of biofilm formation in multidrug-resistant ESKAPE pathogens. It discusses the latest therapeutic advances, including the use of antimicrobial peptides and CRISPR-Cas systems, and the modulation of quorum sensing and iron homeostasis, which offer promising strategies for countering resistance. The integration of CRISPR-based tools and biofilm-targeted approaches provides a potential framework for managing ESKAPE infections. By highlighting the spread of current resistance mutations and biofilm-targeted approaches, the review aims to contribute significantly to advancing our understanding and strategies in combatting this pressing global health challenge.

Efficacy of Three Kayviruses Against Staphylococcus aureus Strains Isolated from COVID-19 Patients

Background/Objectives: The viral pandemic caused by the SARS-CoV-2 virus has affected millions of people. However, it was noticed that high mortality was often a result of bacterial co-infections. One of the main pathogens responsible for secondary infections in patients with viral respiratory tract infections, including COVID-19, is Staphylococcus aureus. In recent years, the number of infections caused by drug-resistant strains of S. aureus has been growing rapidly, often exceeding the number of infections caused by antibiotic-sensitive strains. In addition, biofilm-related infections are more difficult to treat due to the lower sensitivity of biofilm structure to antibiotics. Bacteriophages are seen as alternative treatment of bacterial infections. Therefore, in our work, we have analyzed the efficacy of three Kayviruses against S. aureus strains isolated from COVID-19 patients. Methods: We analyzed the ability of tested phages to remove S. aureus biofilm both from polystyrene plates as well as from the surface of pulmonary epithelial cells. Results: We have observed that tested Kayviruses had a broad host range. Furthermore, phages were able to effectively reduce biofilm biomass and number of viable cells in pure culture. During our research, none of the tested phages was shown to have a negative effect on cell viability and were able to inhibit the negative effect S. aureus had on cell condition. Conclusions: Our results show tested phages were effective in reducing the biofilm of S. aureus strains isolated from COVID-19 patients, had no adverse effect on lung epithelial cell viability. Therefore, it should be recognized that the properties of three studied Kayviruses give them an advantage in the selection of phages for treatment of staphylococcal infections.

Characterization and anti-biofilm potentiality of an isolated novel Aeromonas hydrophila-infecting bacteriophage AHPMCC11, belonging to the genus Ahphunavirus

Aeromonas hydrophila is a major aquatic habitat pathogen responsible for huge economic losses in the aquaculture and food industries. In this study, a lytic bacteriophage AHPMCC11 was isolated by using A. hydrophila MTCC 1739. AHPMCC11 showed a short latent period of 10 min and the burst size was 215 PFU/cell. AHPMCC11 had potent bacteriolytic activity within 2 h in liquid culture inhibition assay and exhibited biofilm scavenging activity against A. hydrophila MTCC 1739. AHPMCC11 was found stable at a wide range of pH levels (3-12), temperature ranges (4-37 °C), and salinity conditions (0-40 ppt). The AHPMCC11 genome was determined to be 42,439 bp in length with 58.9 % G + C content, 51 CDS, and no tRNA. Comparative genome study suggested that AHPMCC11 may represent a novel species within the Autographiviridae family, belonging to the Ahphunavirus genus. In conclusion, AHPMCC11 might be used as a biocontrol agent in aquaculture and the food industry.

Re-Emergence of Bacteriophages and Their Products as Antibacterial Agents: An Overview

Microbes possess diverse genetic and metabolic traits that help them withstand adverse conditions. Microbial pathogens cause significant economic losses and around 7.7 million human deaths annually. While antibiotics have historically been a lifesaving treatment, their effectiveness is declining due to antibiotic-resistant strains, prompting the exploration of bacterial predation as an alternative. Bacteriophages (BPhs) have reemerged as antibacterial agents, offering advantages over antibiotics, such as (i) high specificity, (ii) self-replication, and (iii) strong killing capacity. This review explores BPh- and enzyme-based antibacterial strategies for infectious disease treatment, discussing phage-antibiotic synergy, the risks of BPh resistance, and the role of quorum sensing in BPh therapy.

Engineering bacteriophages for targeted superbug eradication

The rise of antibiotic-resistant bacteria, termed "superbugs," presents a formidable challenge to global health. These pathogens, often responsible for persistent nosocomial infections, threaten the effectiveness of conventional antibiotic therapies. This review delves into the potential of bacteriophages, viruses specifically targeting bacteria, as a powerful tool to combat superbugs. We examined the latest developments in genetic engineering that improve the efficacy of bacteriophages, focusing on modifications in host range, lysis mechanisms, and their ability to overcome bacterial defense systems. This review article highlights the CRISPR-Cas system as a promising method for precisely manipulating phage genomes, enabling the development of novel phage therapies with enhanced efficacy and specificity. Furthermore, we discussed developing novel phage-based strategies, such as phage cocktails and phage-antibiotic combinations. We also analyzed the challenges and ethical considerations associated with phage engineering, emphasizing the need for responsible and rigorous research to ensure this technology's safe and effective deployment to combat the growing threat of antibiotic resistance.

Isolation, Characterization, and Anti-Biofilm Activity of a Novel Kaypoctavirus Against K24 Capsular Type, Multidrug-Resistant Klebsiella pneumoniae Clinical Isolates

Background/Objectives: The significant outbreak of multidrug-resistant Klebsiella pneumoniae has emerged as a primary global concern associated with high morbidity and mortality rates. Certain strains of K. pneumoniae are highly resistant to most antibiotics available in clinical practice, exacerbating the challenge of bacterial infections. Methods: Phage vB_KpnP_PW7 (vKPPW7) was isolated and characterized. Its morphology, stability, adsorption rate, one-step growth curve, lytic activity, whole-genome sequence analysis, and antibacterial and antibiofilm activities were evaluated. Results: The virulent phage has a 73,658 bp linear dsDNA genome and was classified as a new species of the genus Kaypoctavirus, subfamily Enquatrovirinae, and family Schitoviridae. Phage vKPPW7 has a high adsorption rate, a short latent period, and a large burst size. The phage showed activity against 18 K. pneumoniae isolates with the K24 capsular type but was unable to lyse K. pneumoniae isolates whose capsular type was not classified as K24. Additionally, phage vKPPW7 demonstrated strong stability across various temperatures and pH values. The phage exhibited antibacterial activity, and scanning electron microscopy (SEM) confirmed its ability to lyse MDR K. pneumoniae with the K24 capsular type. Furthermore, phage vKPPW7 effectively removed preformed biofilm and prevented biofilm formation, resulting in reduced biofilm biomass and biofilm viability compared to controls. The architecture of phage-treated biofilms was confirmed under SEM. Conclusions: These findings suggest that phage vKPPW7 holds promise for development as a therapeutic or biocontrol agent.

Novel delivery systems for phages and lysins in the topical management of wound infections: a narrative review

Currently, multidrug-resistant (MDR) bacterial wound infections (WIs) are an extremely challenging clinical problem for physicians. Recently, compared to traditional single liquid delivery drugs, the study of five novel drug delivery systems (i.e., hydrogel, liposomes, electrospun fibers, nanoparticles and nanoemulsion) for phages and their encoded lysins in WI management has become a hot topic. To assess the current landscape of these emerging technologies, we conducted a comprehensive literature search across PubMed, Scopus and Web of Science up to July 2024, using terms such as "phage," "lysin," "wound," "hydrogel," "liposomes," "fibers," "nanoparticles," and "nanoemulsion." The criteria included original studies of five novel delivery systems for phages and lysins in WI management. The findings highlighted the positive effects of the five novel delivery systems for phages and lysins in WI management, significantly reducing wound bacterial populations, and accelerating healing at the injury site. However, the available literature on novel delivery systems for phages and lysins remains limited, particularly for lysins. In conclusion, the application of novel drug delivery systems for phages and lysins showed great potential in combating MDR bacterial WIs.

Phage Therapy for Orthopaedic Infections: The First Three Cases from the United Kingdom

Background: Bacteriophages (phages) are viruses that infect and kill bacteria. The antimicrobial resistance crisis has driven renewed interest in phage therapy, including the use of phages to treat chronic orthopaedic infections. Methods: Here, we present the results of the first three orthopaedic patients treated with phage therapy in the United Kingdom. Results: The first patient was treated in May 2023 and received phages active against Staphylococcus aureus. At nine months follow-up, the patient's wound remained healed, the C-reactive protein normal and the patient was walking independently. The second patient received phages active against Klebsiella pneumoniae and S. aureus; the infection remained unresolved. The third patient received phages active against Staphylococcus epidermidis; at six months follow-up, the patient was free of infection. Endotoxin was considered at least partially responsible for mild self-limiting adverse effects in two cases. Conclusions: These promising results hint at the potential for phage therapy to transform the care of chronic orthopaedic infections.

Phage-Derived Endolysins Against Resistant Staphylococcus spp.: A Review of Features, Antibacterial Activities, and Recent Applications

Antimicrobial resistance is a significant global public health issue, and the dissemination of antibiotic resistance in Gram-positive bacterial pathogens has significantly increased morbidity, mortality rates, and healthcare costs. Among them, Staphylococcus, especially methicillin-resistant Staphylococcus aureus (MRSA), causes a wide range of diseases due to its diverse pathogenic factors and infection strategies. These bacteria also present significant issues in veterinary medicine and food safety. Effectively managing staphylococci-related problems necessitates a concerted effort to implement preventive measures, rapidly detect the pathogen, and develop new and safe antimicrobial therapies. In recent years, there has been growing interest in using endolysins to combat bacterial infections. These enzymes, which are also referred to as lysins, are a unique class of hydrolytic enzymes synthesized by double-stranded DNA bacteriophages. They possess glycosidase, lytic transglycosylase, amidase, and endopeptidase activities, effectively destroying the peptidoglycan layer and resulting in bacterial lysis. This unique property makes endolysins powerful antimicrobial agents, particularly against Gram-positive organisms with more accessible peptidoglycan layers. Therefore, considering the potential benefits of endolysins compared to conventional antibiotics, we have endeavored to gather and review the characteristics and uses of endolysins derived from staphylococcal bacteriophages, as well as their antibacterial effectiveness against Staphylococcus spp. based on conducted experiments and trials.

Successful Treatment of a Patient With Chronic Bronchiectasis Using an Induced Native Phage Cocktail: A Case Report

Bronchiectasis is a well-recognized chronic respiratory disease characterized by a productive cough and multi-microbial activation syndrome (MMAS) of various respiratory infections due to what can be the permanent dilatation of the bronchi. Bronchiectasis represents an ongoing challenge to conventional antibiotic treatment as the damaged bronchial environment remains conducive to ongoing opportunistic infections and microbial mutations, leading to multi-drug resistance. Standard treatment guidelines are designed to promptly identify and address the primary infection. Despite the strong focus on identification of the primary infection in each new episode, by combining clinical history, and high-resolution computed tomography (HRCT), a high proportion of patients remain classified as "idiopathic". Important underlying infections, such as Aspergillus and other mold infections, Pseudomonas aeruginosa, Mycobacterium, Mycoplasma, and various viruses, are frequently not identified for prolonged periods of time, and selected broad-spectrum antibiotics are often ineffective. The introduction of Induced Native Phage Therapy in 2021 and Induced Native Phage cocktails in 2024 provides a new treatment alternative that induces naturally occurring phages to eliminate specifically targeted acute and chronic mixed infections even in cases of multi-drug resistant infections as seen in chronic bronchiectasis. This article will present the successful long-term results in a case study demonstrating the speed, gentleness, and effectiveness of induced native phage cocktails in a 45-year-old male with life-long asthma resulting in multi-microbial activation syndrome in severe non-cystic fibrosis bronchiectasis for the last 20 years.

Beyond antibiotics: mesenchymal stem cells and bacteriophages-new approaches to combat bacterial resistance in wound infections

Wound management is a major global health problem. With the rising incidence of diabetic wounds, accidents, and other injuries, the demand for prompt wound treatment has become increasingly critical. Millions of people suffer from serious, large wounds resulting from major accidents, surgeries, and wars. These wounds require considerable time to heal and are susceptible to infection. Furthermore, chronic wounds, particularly in elderly and diabetic patients, often require frequent medical interventions to prevent complications. Consequently, wound management imposes a significant economic burden worldwide. The complications arising from wound infections can vary from localized issues to systemic effects. The most severe local complication of wound infection is the non-healing, which results from the disruption of the wound-healing process. This often leads to significant pain, discomfort, and psychological trauma for the patient. Systemic complications may include cellulitis, osteomyelitis, and septicemia. Mesenchymal stem cells are characterized by their high capacity for division, making them suitable candidates for the treatment of tissue damage. Additionally, they produce antimicrobial peptides and various cytokines, which enhance their antimicrobial activity. Evidence shows that phages are effective in treating wound-related infections, and phage therapy has proven to be highly effective for patients when administered correctly. The purpose of this article is to explore the use of bacteriophages and mesenchymal stem cells in wound healing and infection management.

Combined Effects of the Pijolavirus UFJF_PfSW6 Phage and Sodium Hypochlorite for Reducing Pseudomonas fluorescens Biofilm

Pseudomonas are significant spoilage bacteria in raw milk and dairy products, primarily due to their ability to form biofilms and resist disinfection. This study explored the effects of the UFJF_PfSW6 phage combined with sodium hypochlorite in reducing Pseudomonas fluorescens biofilms on stainless steel at various temperatures and ages. Biofilms were formed using P. fluorescens UFV 041 in UHT milk, incubated at 4 °C and 30 °C for 2 and 7 days. Two lytic phages were compared, with UFJF_PfSW6 showing superior activity, reducing cell counts by 0.8 to 2.0 logs CFU/cm2 depending on conditions. Increasing the contact time of the UFJF_PfSW6 phage from 4 to 8 h did not significantly affect the reduction in mature biofilms. The individual treatments of the phage and sodium hypochlorite (100 mg/L) reduced bacterial counts by 0.9 and 0.6 log CFU/cm2 at 30 °C, and 1.3 and 1.2 log CFU/cm2 at 4 °C, respectively. However, their sequential application achieved greater reductions, reaching 1.3 and 1.8 log CFU/cm2 for biofilms formed at 30 °C and 4 °C, respectively. These findings suggest a promising strategy for controlling P. fluorescens in the food industry. Our findings suggest that the UFJF_PfSW6 phage combined with chlorine improves the removal of P. fluorescens biofilms.

Plasma activated water pre-treatment substantially enhances phage activity against Proteus mirabilis biofilms

The ongoing antimicrobial resistance crisis has incentivised research into alternative antibacterial and antibiofilm agents. One of them is plasma-activated water (PAW), which is produced by exposing water to a cold plasma discharge. This process generates a diverse array of reactive oxygen and nitrogen species (ROS/RNS) with antimicrobial properties. Another intensively studied class of alternative antimicrobials are bacteriophages, attracting attention due to their specificity and strong antibacterial activity. As combinations of different types of antimicrobials are known to often exhibit synergistic interactions, in this study we investigated the combined use of cold atmospheric-pressure plasma-activated water and the bacteriophage vB_PmiS_PM-CJR against Proteus mirabilis biofilms as a potential option for treatment of catheter-associated urinary tract infections (CAUTIs). We compared the effect of two cold plasma discharge setups for PAW production on its antimicrobial efficacy against P. mirabilis planktonic and biofilm cultures. Next, we assessed the stability of the phage vB_PmiS_PM-CJR in PAW. Finally, we tested the antimicrobial activity of the phages and PAW against biofilms, both individually and in combinations. Our findings demonstrate that the combination of PAW with phage is more effective against biofilms compared to individual treatments, being able to reduce the number of biofilm-embedded cells by approximately 4 log. We were also able to show that the order of treatment plays an important role in the anti-biofilm activity of the phage-PAW combination, as the exposure of the biofilm to PAW prior to phage administration results in a stronger effect than the reverse order. This research underlines PAW's ability to potentiate phage activity, showcasing a considerable reduction in biofilm viability and biomass. Additionally, it contributes to the growing body of evidence supporting the use of phage-based combinatorial treatments. Overall, this sequential treatment strategy demonstrates the potential of leveraging multiple approaches to address the mounting challenge of antibiotic resistance and offers a promising avenue for enhancing the efficacy of CAUTI management.

Assessment of Bacteriophage Pharmacokinetic Parameters After Intra-Articular Delivery in a Rat Prosthetic Joint Infection Model

Prosthetic joint infections (PJIs) are a serious complication of orthopedic surgery. Bacteriophage (phage) therapy shows promise as an adjunctive treatment but requires further study, particularly in its pharmacokinetics. Consequently, we performed a pharmacokinetic assessment of phage therapy for PJIs using a Staphylococcus epidermidis Kirschner wire-based prosthesis rat model. We used 52 male Sprague-Dawley rats in four groups: negative controls (no phage, sterile implant), PJI controls (bacteria, no phage), sterile phage (phages given, sterile implant), and PJI (bacteria, phages given). The PJI groups were inoculated with ~106 CFU of S. epidermidis. The groups receiving phage were intra-articularly injected with ~108 PFU of vB_SepM_Alex five days post-implantation. The rats were euthanized between 30 min and 48 h post-injection. The measured phage concentrations between the PJI rats and the sterile controls in periarticular tissues were not significantly different. In a noncompartmental pharmacokinetic analysis, the estimated phage half-lives were under 6 h (combined: 3.73 [IQR, 1.45, 10.07]). The maximum phage concentrations were reached within 2 h after administration (combined: 0.75 [0.50, 1.75]). The estimated phage mean residence time was approximately three hours (combined: 3.04 [1.44, 4.19]). Our study provides a preliminary set of pharmacokinetic parameters that can inform future phage dosing studies and animal models of phage therapy for PJIs.

Comprehensive Approaches to Combatting Acinetobacter baumannii Biofilms: From Biofilm Structure to Phage-Based Therapies

Acinetobacter baumannii-a multidrug-resistant (MDR) pathogen that causes, for example, skin and soft tissue wounds; urinary tract infections; pneumonia; bacteremia; and endocarditis, particularly due to its ability to form robust biofilms-poses a significant challenge in clinical settings. This structure protects the bacteria from immune responses and antibiotic treatments, making infections difficult to eradicate. Given the rise in antibiotic resistance, alternative therapeutic approaches are urgently needed. Bacteriophage-based strategies have emerged as a promising solution for combating A. baumannii biofilms. Phages, which are viruses that specifically infect bacteria, offer a targeted and effective means of disrupting biofilm and lysing bacterial cells. This review explores the current advancements in bacteriophage therapy, focusing on its potential for treating A. baumannii biofilm-related infections. We described the mechanisms by which phages interact with biofilms, the challenges in phage therapy implementation, and the strategies being developed to enhance its efficacy (phage cocktails, engineered phages, combination therapies with antibiotics). Understanding the role of bacteriophages in both biofilm disruption and in inhibition of its forming could pave the way for innovative treatments in combating MDR A. baumannii infections as well as the prevention of their development.

Characterization of two Friunavirus phages and their inhibitory effects on biofilms of extremely drug resistant Acinetobacter baumannii in Dakar, Senegal

BACKGROUND

Acinetobacter baumannii is a gram-negative, opportunistic pathogen, that is responsible for a wide variety of infections and is a significant cause of hospital-acquired infections. A. baumannii is listed by the World Health Organization (WHO) as a critical priority pathogen because of its high level of antibiotic resistance and the urgent need for alternative treatment solutions. To address this challenge, bacteriophages have been used to combat bacterial infections for more than a century, and phage research has regained interest in recent years due to antimicrobial resistance (AMR). However, although the vast majority of deaths from the AMR crisis will occur in developing countries in Africa and Asia, few phages' studies have been conducted in these regions. In this study, we present a comprehensive characterization of the bacteriophages vAbBal23 and vAbAbd25, actives against extremely drug-resistant (XDR) A. baumannii.

METHODS

Phages were isolated from environmental wastewaters in Dakar, Senegal. The host-range, thermal and pH stabilities, infection kinetics, one step growth assay, antibiofilm activity assay, sequencing, and genomic analysis, were performed to characterize the isolated phages.

RESULTS

Comparative genomic and phylogenetic analyses revealed that vAbBal23 and vAbAbd25 belong to the Caudoviricetes class, Autographiviridae family and Friunavirus genus. Both phages demonstrated activity against strains with capsular type KL230. They were stable over a wide pH range (pH 3 to 9) and at temperatures ranging from 25 °C to 40 °C. Additionally, the phages exhibited notable activity against both planktonic and biofilm cells of targeted extremely drug resistant A. baumannii. The results presented here indicate the lytic nature of vAbBal23 and vAbAbd25. This is further supported by the absence of genes encoding toxins, resistance genes and bacterial virulence factors, highlighting their potential for future phage applications.

CONCLUSION

Phages vAbBal23 and vAbAbd25 are promising biological agents that can infect A. baumannii, making them suitable candidates for use in phage therapies.

Phage therapy: A primer for orthopaedic trauma surgeons

Phage therapy (PT) continues to attract interest in the fight against fracture-related infection (FRI), particularly for recurring infections that have not been resolved using conventional therapeutic approaches. The journey PT has taken from early clinical application in the pre-antibiotic era to its recent reintroduction to western clinical practice has been accelerated by the increased prevalence of multi-drug resistant (MDR) pathogens in the clinic. This review will present PT's potential as a precise, adaptable, and effective treatment modality, with a focus on patient and phage selection, as well as the various administration protocols currently applied to patients. The challenges for PT, for example the most optimal application technique and dosing, are also discussed and underscore the importance of personalized approaches and the urgent need for more robust clinical evidence. Future perspectives, including phage engineering and innovative delivery systems will be discussed, as they may broaden the applicability of PT to a point where it may become a standard rather than an option of last resort for orthopedic infection management.

Combating chlorine-resistant marine Klebsiella pneumoniae biofilms with chlorine-tolerant bacteriophages

Biofilm formation presents a significant challenge in health care, food industries, water distribution systems, etc. In addition to their inherent resistance to various stresses and biocides, emerging resistance against widely used biocides like chlorine is a growing concern. The strong link between chlorine resistance and the development of antibiotic resistance among microbes further exacerbates this issue. Therefore, it is highly desirable to devise a method to mitigate the problems associated with biofilms formed by Chlorine Resistant Bacteria (CRB). In this study, a highly chlorine resistant, biofilm-forming Klebsiella pneumoniae was isolated from the cooling water system of a nuclear power plant employing continuous chlorination for biofilm control. Interestingly, K. pneumoniae was found to enhance biofilm formation under the influence of increasing concentrations of chlorine, highlighting the limitations of chlorination-based biofilm control measures. As a remedial measure, chlorine resistant bacteriophages specific to K. pneumoniae were successfully isolated from the same water sample. These bacteriophages effectively inhibited planktonic growth biofilm formation and removed preformed biofilms. Whole-genome sequencing of two of the promising bacteriophages confirmed their identity as novel bacteriophages specific to K. pneumoniae. The absence of any antibiotic-resistant gene, virulent factor(s), or gene associated with the lysogenic life cycle further supports their suitability for environmental applications. This study provides valuable insights into the prevalence of chlorine resistant, pathogenic bacteria in cooling water distribution systems. It also highlights the promising application of bacteriophages to mitigate chlorine resistant bacteria and their biofilms.

Phage-encoded depolymerases as a strategy for combating multidrug-resistant Acinetobacter baumannii

Acinetobacter baumannii, a predominant nosocomial pathogen, represents a grave threat to public health due to its multiple antimicrobial resistance. Managing patients afflicted with severe infections caused by multiple drug-resistant A. baumannii is particularly challenging, given the associated high mortality rates and unfavorable prognoses. The diminishing efficacy of antibiotics against this superbug underscores the urgent necessity for novel treatments or strategies to address this formidable issue. Bacteriophage-derived polysaccharide depolymerase enzymes present a potential approach to combating this pathogen. These enzymes target and degrade the bacterial cell's exopolysaccharide, capsular polysaccharide, and lipopolysaccharide, thereby disrupting biofilm formation and impairing the bacteria's defense mechanisms. Nonetheless, the narrow host range of phage depolymerases limits their therapeutic efficacy. Despite the benefits of these enzymes, phage-resistant strains have been identified, highlighting the complexity of phage-host interactions and the need for further investigation. While preliminary findings are encouraging, current investigations are limited, and clinical trials are imperative to advance this treatment approach for broader clinical applications. This review explores the potential of phage-derived depolymerase enzymes against A. baumannii infections.

In vitro and in vivo assessment of the competence of a novel lytic phage vB_EcoS_UTEC10 targeting multidrug resistant Escherichia coli with a robust biofilm eradication activity

Escherichia coli (E. coli) is a leading cause of human infections worldwide and is considered a major cause of nosocomial infections, sepsis, meningitis and diarrhea. Lately, there has been an alarming increase in the incidence of antimicrobial resistance among clinical E. coli isolates. In the current study, a novel bacteriophage (phage) vB_EcoS_UTEC10 was isolated and characterized. The isolated phage showed high stability over wide temperature and pH ranges beside its promising bacteriolytic activity against multidrug resistant (MDR) E. coli isolates. In addition, vB_EcoS_UTEC10 showed a marked antibiofilm capability against mature E. coli biofilms. Genomic investigation revealed that vB_EcoS_UTEC10 has a double stranded DNA genome that consists of 44,772 bp comprising a total of 73 open reading frames (ORFs), out of which 35 ORFs were annotated as structural or functional proteins, and none were related to antimicrobial resistance or lysogeny. In vivo investigations revealed a promising bacteriolytic activity of vB_EcoS_UTEC10 against MDR E. coli which was further supported by a significant reduction in bacterial load in specimens collected from the phage-treated mice. Histopathology examination demonstrated minimal signs of inflammation and necrosis in the tissues of phage-treated mice compared to the degenerative tissue damage observed in untreated mice. In summary, the present findings suggest that vB_EcoS_UTEC10 has a remarkable ability to eradicate MDR E. coli infections and biofilms. These findings could be further invested for the development of targeted phage therapies that offer a viable alternative to traditional antibiotics against resistant E. coli.

Isolation and evaluation of bacteriophage cocktail for the control of colistin-resistant Escherichia coli

The frequent emergence of colistin-resistant E. coli worldwide drives the exploration of alternative therapies, and bacteriophages (phages) have emerged as promising candidates to tackle this challenge. In this study, three E. coli phages were isolated, screened, and evaluated against 96 colistin-resistant strains obtained from diverse sources. The combined recognition rate for these strains was 43.6 %, while individually it ranged from 17.0 % to 24.5 %. Notably, among the tested phages (FJ3-79, SD1-92L, and FJ4-63), FJ4-63 demonstrated exceptional characteristics in regulating host population dynamics upon infection by exhibiting a shorter latent period (20 min) and a larger burst size (95.99 ± 3.61 PFU/cell). Furthermore, it exhibited relative stability at pH 3-11 and below 60 °C. Transmission electron microscopy and genomic analysis classified phage FJ4-63 belongs to the Dhakavirus genus within the Straboviridae family. Its genome comprised a linear double-stranded DNA measuring 169,669 bp (containing 272 coding sequences) with a GC content of 39.76 %, of which 93 (34.2 %) had known functions, and the remaining 177 were annotated as hypothetical proteins. Additionally, two tRNAs were recognized, possess the "holin-endolysin" lytic system, and no resistance or virulence genes were detected. The phylogenetic tree and average nucleotide identity (ANI) analysis revealed that phage FJ4-63 exhibited the highest similarity to Escherichia phage C6 (679410.1), indicating a consistent close relationship within the same branch. The cocktail comprising three phages exhibits enhanced in vitro bactericidal efficacy compared to a single phage. At high doses with MOI = 100, it rapidly and completely eradicates bacteria within 1 h while significantly reducing bacterial biofilms. All this evidence suggests that lytic phages offer an effective solution for clinical treatment, with a phage cocktail demonstrating greater potential in the alternative management of colistin-resistant E. coli infections.

The potential use of bacteriophages as antibacterial agents in dental infection

Dental infections, such as apical Periodontitis, periodontitis, and peri-implantitis (PI), are closely associated with specific bacterial species, including Streptococcus mutans (S. mutans), Porphyromonas gingivalis (P. gingivalis), and Fusobacterium nucleatum (F. nucleatum), among others. Antibiotics are extensively utilized for prophylactic and therapeutic purposes in the treatment of dental infections and other dental-related issues. Unfortunately, the rapid emergence of antimicrobial resistance has accompanied the increased use of antibiotics in recent years. Specific bacterial pathogens have reached a critical stage of antibiotic resistance, characterized by the proliferation of pan-resistant strains and the scarcity of viable therapeutic alternatives. Therapeutic use of particular bacteriophage (phage) particles that target bacterial pathogens is one potential alternative to antibiotics that are now being seriously considered for treating bacterial illnesses. A kind of virus known as a phage is capable of infecting and eliminating bacteria. Because they can't infect cells in plants and animals, phages might be a harmless substitute for antibiotics. To control oral disorders including periodontitis and dental caries, several research have been conducted in this area to study and identify phages from human saliva and dental plaque. The capacity of these agents to disturb biofilms expands their effectiveness against dental plaque biofilms and oral pathogens in cases of periodontitis, PI, and apical periodontitis. This review summarizes the current antibacterial properties of phages used to treat a variety of dental infections, such as periodontitis, peri-implantitis, infected dentin, and apical periodontitis.

Phage therapy could be key to conquering persistent bacterial lung infections in children

Persistent bacterial lung infections in children lead to significant morbidity and mortality due to antibiotic resistance. In this paper, we describe how phage therapy has shown remarkable efficacy in preclinical and clinical studies, demonstrating significant therapeutic benefits through various administration routes. Ongoing trials are evaluating its safety and effectiveness against different pathogens. Advancing phage therapy through systematic studies and international collaboration could provide a viable alternative to traditional antibiotics for persistent infections.

Biofilm Prevention and Removal in Non-Target Pseudomonas Strain by Siphovirus-like Coliphage

Background/Objectives. Bacteriophages have gained significant interest as a potential solution to combat harmful bacteria, especially in the fight against antimicrobial resistance. With the rise in drug-resistant microorganisms, the medical community is increasingly exploring new alternatives to traditional antibiotics, and bacteriophages offer several advantages in this regard. However, phage applications still face some challenges, such as host specificity. Methods. In this study, a somatic Siphovirus-like coliphage (SOM7) was tested for inhibiting the biofilm-forming capacity of the non-target strain Pseudomonas aeruginosa (ATTC 10145). The phage-sensitive strain E. coli WG5 was used as a control. The selected microorganisms were first tested for growth in the presence of SOM7 at three different concentrations (105, 107, and 109 PFU/mL). Results. As expected, the phage-sensitive E. coli WG5 was fully inhibited by the coliphage, and no phage-related affection on the growth rate was observed for the SOM7-resistant P. aeruginosa. More notably, increasing concentrations of SOM7 significantly reduced both the biofilm-forming capacity and the amount of pre-established bacterial biofilm of the phage-insensitive P. aeruginosa (24.9% and 38.8% reduction in the biofilm-forming ability, and 18.8% and 28.0% biofilm degradation for 107 PFU/mL and 109 PFU/mL SOM7, respectively; p < 0.05). These results were supported by transmission electron microscopy (TEM) imaging, providing unprecedent evidence for the interaction of the somatic coliphage with the non-host strain. Conclusions. Although more studies in other biofilm models are necessary, our results show for the very first time that bacteriophages could potentially be used as an alternative to achieve desired anti-biofilm and biofilm-degrading activity in non-host bacterial strains.

Biofilm Formation in Chronic Infections: A Comprehensive Review of Pathogenesis, Clinical Implications, and Novel Therapeutic Approaches

Biofilms are intricate microbial communities on various surfaces, including medical devices and biological tissues, encased within a protective matrix of extracellular polymeric substances. Their formation and persistence are significant factors in the pathogenesis of chronic infections, contributing to the complexity of treatment and increased resistance to antimicrobial agents. This review explores the multifaceted nature of biofilms, focusing on their formation, structure, and the genetic and environmental factors that contribute to their resilience. Biofilms are particularly problematic in chronic infections, such as those associated with medical implants and persistent wounds, due to their ability to evade both the host immune response and conventional therapeutic strategies. The review also discusses the current challenges in diagnosing biofilm-associated infections and the limitations of existing treatment options. Emerging therapeutic approaches, including novel antibiofilm agents, physical disruption techniques, and biological therapies such as phage therapy, are examined for their potential to improve treatment outcomes. Innovations in drug delivery systems and preventive measures, such as biofilm-resistant materials, are also highlighted as promising developments. This comprehensive overview aims to provide insights into the mechanisms of biofilm-related infections and to guide future research and clinical practice. This review contributes to the ongoing efforts to enhance patient care and combat the growing challenge of antimicrobial resistance by addressing the critical need for effective strategies to manage and prevent biofilm-associated chronic infections.

Phage therapy: A novel approach against multidrug-resistant pathogens

The rapid rise of multidrug-resistant (MDR) organisms has created a critical need for alternative treatment options. Phage therapy is gaining attention as an effective way to fight bacterial infections by using lytic bacteriophages to specifically target and kill harmful bacteria. This review discusses several phage therapeutic options and emphasizes new developments in phage biology. Phage treatment has proven to be successful against MDR bacteria, as evidenced by multiple human clinical trials that indicate favorable results in treating a range of diseases caused by these pathogens. Despite these promising results, challenges such as phage resistance, regulatory hurdles, and the need for standardized treatment protocols remain. To effectively combat MDR bacterial infections, future research must focus on enhancing phage effectiveness, guaranteeing safety for human usage and incorporating phage therapy into clinical practice.

Characterization and Anti-Biofilm Activity of Lytic Enterococcus Phage vB_Efs8_KEN04 against Clinical Isolates of Multidrug-Resistant Enterococcus faecalis in Kenya

Enterococcus faecalis (E. faecalis) is a growing cause of nosocomial and antibiotic-resistant infections. Treating drug-resistant E. faecalis requires novel approaches. The use of bacteriophages (phages) against multidrug-resistant (MDR) bacteria has recently garnered global attention. Biofilms play a vital role in E. faecalis pathogenesis as they enhance antibiotic resistance. Phages eliminate biofilms by producing lytic enzymes, including depolymerases. In this study, Enterococcus phage vB_Efs8_KEN04, isolated from a sewage treatment plant in Nairobi, Kenya, was tested against clinical strains of MDR E. faecalis. This phage had a broad host range against 100% (26/26) of MDR E. faecalis clinical isolates and cross-species activity against Enterococcus faecium. It was able to withstand acidic and alkaline conditions, from pH 3 to 11, as well as temperatures between -80 °C and 37 °C. It could inhibit and disrupt the biofilms of MDR E. faecalis. Its linear double-stranded DNA genome of 142,402 bp contains 238 coding sequences with a G + C content and coding gene density of 36.01% and 91.46%, respectively. Genomic analyses showed that phage vB_Efs8_KEN04 belongs to the genus Kochikohdavirus in the family Herelleviridae. It lacked antimicrobial resistance, virulence, and lysogeny genes, and its stability, broad host range, and cross-species lysis indicate strong potential for the treatment of Enterococcus infections.

Characterization of two virulent Salmonella phages and transient application in egg, meat and lettuce safety

Salmonella, a prominent foodborne pathogen, has posed enduring challenges to the advancement of food safety and global public health. The escalating concern over antibiotic misuse, resulting in the excessive presence of drug residues in animal-derived food products, necessitates urgent exploration of alternative strategies for Salmonella control. Bacteriophages emerge as promising green biocontrol agents against pathogenic bacteria. This study delineates the identification of two novel virulent Salmonella phages, namely phage vB_SalS_ABTNLsp11241 (referred to as sp11241) and phage 8-19 (referred to as 8-19). Both phages exhibited efficient infectivity against Salmonella enterica serotype Enteritidis (SE). Furthermore, this study evaluated the effectiveness of two phages to control SE in three different foods (whole chicken eggs, raw chicken meat, and lettuce) at different MOIs (1, 100, and 10000) at 4°C. It's worth noting that sp11241 and 8-19 achieved complete elimination of SE on eggs after 3 h and 6 h at MOI = 100, and after 2 h and 5 h at MOI = 10000, respectively. After 12 h of treatment with sp11241, a maximum reduction of 3.17 log10 CFU/mL in SE was achieved on raw chicken meat, and a maximum reduction of 3.00 log10 CFU/mL was achieved on lettuce. Phage 8-19 has the same effect on lettuce as sp11241, but is slightly less effective than sp11241 on chicken meat (a maximum 2.69 log10 CFU/mL reduction). In conclusion, sp11241 and 8-19 exhibit considerable potential for controlling Salmonella contamination in food at a low temperature and represent viable candidates as green antibacterial agents for food applications.

Characterization of the novel broad-spectrum lytic phage Phage_Pae01 and its antibiofilm efficacy against Pseudomonas aeruginosa

Introduction

Pseudomonas aeruginosa is present throughout nature and is a common opportunistic pathogen in the human body. Carbapenem antibiotics are typically utilized as a last resort in the clinical treatment of multidrug-resistant infections caused by P. aeruginosa. The increase in carbapenem-resistant P. aeruginosa poses an immense challenge for the treatment of these infections. Bacteriophages have the potential to be used as antimicrobial agents for treating antibiotic-resistant bacteria.

Methods and Results

In this study, a new virulent P. aeruginosa phage, Phage_Pae01, was isolated from hospital sewage and shown to have broad-spectrum antibacterial activity against clinical P. aeruginosa isolates (83.6%). These clinical strains included multidrug-resistant P. aeruginosa and carbapenem-resistant P. aeruginosa. Transmission electron microscopy revealed that the phage possessed an icosahedral head of approximately 80 nm and a long tail about 110  m, indicating that it belongs to the Myoviridae family of the order Caudovirales. Biological characteristic analysis revealed that Phage_Pae01 could maintain stable activity in the temperature range of 4~ 60°C and pH range of 4 ~ 10. According to the in vitro lysis kinetics of the phage, Phage_Pae01 demonstrated strong antibacterial activity. The optimal multiplicity of infection was 0.01. The genome of Phage_Pae01 has a total length of 93,182 bp and contains 176 open reading frames (ORFs). The phage genome does not contain genes related to virulence or antibiotic resistance. In addition, Phage_Pae01 effectively prevented the formation of biofilms and eliminated established biofilms. When Phage_Pae01 was combined with gentamicin, it significantly disrupted established P. aeruginosa biofilms.

Conclusion

We identified a novel P. aeruginosa phage and demonstrated its effective antimicrobial properties against P. aeruginosa in both the floating and biofilm states. These findings offer a promising approach for the treatment of drug-resistant bacterial infections in clinical settings.

A New Casjensviridae Bacteriophage Isolated from Hospital Sewage for Inactivation of Biofilms of Carbapenem Resistant Klebsiella pneumoniae Clinical Isolates

Klebsiella pneumoniae, a member of the ESKAPE pathogen group, is a prominent cause of hospital-acquired infections. The WHO has recognized carbapenem-resistant K. pneumoniae as a critical-one priority pathogen. These resilient superbugs have the ability to form biofilms and present a significant global threat. In the present study, we isolated and characterized a bacteriophage SAKp02, from hospital sewage, infectious to carbapenem-resistant K. pneumoniae patient isolates. SAKp02 could infect 43 of 72 clinical isolates, indicating a broad host spectrum. Whole genome analysis classified SAKp02 within the family Casjensviridae, with a 59,343 bp genome encoding 82 ORFs. Comparative genomic analysis revealed significant differences between SAKp02 and its closest viruses, indicating a distinct genetic makeup positioning it as a novel phage strain within the lineage. The SAKp02 genome comprises bacteriolytic enzymes, including holin, endolysin, and phage depolymerase, crucial for bacterial lysis and biofilm disruption. It reduced biofilm biomass by over threefold compared to the control and eradicated 99% of viable cells within a 4 h treatment period. Scanning electron microscopy corroborated the ability of the phage to dismantle biofilm matrices and lyse bacterial cells. Safe and effective treatments are warranted, and hence, the fully characterized lytic phages with therapeutic potential against drug-resistant clinical isolates of bacteria are needed. Our study is the first to report the antibacterial and antibiofilm activity of Casjensviridae phages, and our discovery of a novel K. pneumoniae phage broadens the arsenal against the bacteria.

Prophage induction can facilitate the in vitro dispersal of multicellular Streptomyces structures

Streptomyces are renowned for their prolific production of specialized metabolites with applications in medicine and agriculture. These multicellular bacteria present a sophisticated developmental cycle and play a key role in soil ecology. Little is known about the impact of Streptomyces phage on bacterial physiology. In this study, we investigated the conditions governing the expression and production of "Samy", a prophage found in Streptomyces ambofaciens ATCC 23877. This siphoprophage is produced simultaneously with the activation of other mobile genetic elements. Remarkably, the presence and production of Samy increases bacterial dispersal under in vitro stress conditions. Altogether, this study unveiled a new property of a bacteriophage infection in the context of multicellular aggregate dynamics.

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.

Pillar[n]arenes in the Fight against Biofilms: Current Developments and Future Perspectives

The global surge in bacterial infections, compounded by the alarming escalation of drug-resistant strains, has evolved into a critical public health crisis. Among the challenges posed, biofilms stand out due to their formidable resistance to conventional antibiotics. This review delves into the burgeoning potential of pillar[n]arenes, distinctive macrocyclic host molecules, as promising anti-biofilm agents. The review is structured into two main sections, each dedicated to exploring distinct facets of pillar[n]arene applications. The first section scrutinizes functionalized pillar[n]arenes with a particular emphasis on cationic derivatives. This analysis reveals their significant efficacy in inhibiting biofilm formation, underscoring the pivotal role of specific chemical attributes in combating microbial communities. The second section of the review shifts its focus to inclusion complexes, elucidating how pillar[n]arenes serve as encapsulation platforms for antibiotics. This encapsulation enhances the stability of antibiotics and enables a controlled release, thereby amplifying their antibacterial activity. The examination of inclusion complexes provides valuable insights into the potential synergy between pillar[n]arenes and traditional antibiotics, offering a novel avenue for overcoming biofilm resistance. This comprehensive review highlights the escalating global threat of bacterial infections and the urgent need for innovative strategies to counteract drug-resistant biofilms. The unique properties of pillar[n]arenes, both as functionalized molecules and as inclusion complex hosts, position them as promising candidates in the quest for effective anti-biofilm agents. The exploration of their distinct mechanisms opens new avenues for research and development in the ongoing battle against bacterial infections and biofilm-related health challenges.

Elimination of Pathogen Biofilms via Postbiotics from Lactic Acid Bacteria: A Promising Method in Food and Biomedicine

Pathogenic biofilms provide a naturally favorable barrier for microbial growth and are closely related to the virulence of pathogens. Postbiotics from lactic acid bacteria (LAB) are secondary metabolites and cellular components obtained by inactivation of fermentation broth; they have a certain inhibitory effect on all stages of pathogen biofilms. Postbiotics from LAB have drawn attention because of their high stability, safety dose parameters, and long storage period, which give them a broad application prospect in the fields of food and medicine. The mechanisms of eliminating pathogen biofilms via postbiotics from LAB mainly affect the surface adhesion, self-aggregation, virulence, and QS of pathogens influencing interspecific and intraspecific communication. However, there are some factors (preparation process and lack of target) which can limit the antibiofilm impact of postbiotics. Therefore, by using a delivery carrier and optimizing process parameters, the effect of interfering factors can be eliminated. This review summarizes the concept and characteristics of postbiotics from LAB, focusing on their preparation technology and antibiofilm effect, and the applications and limitations of postbiotics in food processing and clinical treatment are also discussed.

Anti-Biofilm Strategies: A Focused Review on Innovative Approaches

Biofilm (BF) can give rise to systemic infections, prolonged hospitalization times, and, in the worst case, death. This review aims to provide an overview of recent strategies for the prevention and destruction of pathogenic BFs. First, the main phases of the life cycle of BF and maturation will be described to identify potential targets for anti-BF approaches. Then, an approach acting on bacterial adhesion, quorum sensing (QS), and the extracellular polymeric substance (EPS) matrix will be introduced and discussed. Finally, bacteriophage-mediated strategies will be presented as innovative approaches against BF inhibition/destruction.

Bacteriophages of Thermophilic 'Bacillus Group' Bacteria-A Systematic Review, 2023 Update

Bacteriophages associated with thermophiles are gaining increased attention due to their pivotal roles in various biogeochemical and ecological processes, as well as their applications in biotechnology and bionanotechnology. Although thermophages are not suitable for controlling bacterial infections in humans or animals, their individual components, such as enzymes and capsid proteins, can be employed in molecular biology and significantly contribute to the enhancement of human and animal health. Despite their significance, thermophages still remain underrepresented in the known prokaryotic virosphere, primarily due to limited in-depth investigations. However, due to their unique properties, thermophages are currently attracting increasing interest, as evidenced by several newly discovered phages belonging to this group. This review offers an updated compilation of thermophages characterized to date, focusing on species infecting the thermophilic bacilli. Moreover, it presents experimental findings, including novel proteomic data (39 proteins) concerning the model TP-84 bacteriophage, along with the first announcement of 6 recently discovered thermophages infecting Geobacillus thermodenitrificans: PK5.2, PK2.1, NIIg10.1, NIIg2.1, NIIg2.2, and NIIg2.3. This review serves as an update to our previous publication in 2021.

Aptamer-based therapy for fighting biofilm-associated infections

Biofilms are key players in the pathogenesis of most of chronic infections associated with host tissue or fluids and indwelling medical devices. These chronic infections are hard to be treated due to the increased biofilms tolerance towards antibiotics in comparison to planktonic (or free living) cells. Despite the advanced understanding of their formation and physiology, biofilms continue to be a challenge and there is no standardized therapeutic approach in clinical practice to eradicate them. Aptamers offer distinctive properties, including excellent affinity, selectivity, stability, making them valuable tools for therapeutic purposes. This review explores the flexibility and designability of aptamers as antibiofilm drugs but, importantly, as targeting tools for diverse drug and delivery systems. It highlights specific examples of application of aptamers in biofilms of diverse species according to different modes of action including inhibition of motility and adhesion, blocking of quorum sensing molecules, and dispersal of biofilm-cells to planktonic state. Moreover, it discusses the limitations and challenges that impaired an increased success of the use of aptamers on biofilm management, as well as the opportunities related to aptamers modifications that can significantly expand their applicability on the biofilm field.

Microbiome Dynamics: A Paradigm Shift in Combatting Infectious Diseases

Infectious diseases have long posed a significant threat to global health and require constant innovation in treatment approaches. However, recent groundbreaking research has shed light on a previously overlooked player in the pathogenesis of disease-the human microbiome. This review article addresses the intricate relationship between the microbiome and infectious diseases and unravels its role as a crucial mediator of host-pathogen interactions. We explore the remarkable potential of harnessing this dynamic ecosystem to develop innovative treatment strategies that could revolutionize the management of infectious diseases. By exploring the latest advances and emerging trends, this review aims to provide a new perspective on combating infectious diseases by targeting the microbiome.

A new Rogue-like Escherichia phage UDF157lw to control Escherichia coli O157:H7

Introduction

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is one of the notorious foodborne pathogens causing high mortality through the consumption of contaminated food items. The food safety risk from STEC pathogens could escalate when a group of bacterial cells aggregates to form a biofilm. Bacterial biofilm can diminish the effects of various antimicrobial interventions and enhance the pathogenicity of the pathogens. Therefore, there is an urgent need to have effective control measurements. Bacteriophages can kill the target bacterial cells through lytic infection, and some enzymes produced during the infection have the capability to penetrate the biofilm for mitigation compared to traditional interventions. This study aimed to characterize a new Escherichia phage vB_EcoS-UDF157lw (or UDF157lw) and determine its antimicrobial efficacy against E. coli O157:H7.

Methods

Phage characterization included biological approaches, including phage morphology, one-step growth curve, stability tests (pH and temperature), and genomic approaches (whole-genome sequencing). Later, antimicrobial activity tests, including productive infection against susceptible bacterial strains, in vitro antimicrobial activity, and anti-biofilm, were conducted.

Results

UDF157lw is a new member of the phages belonging to the Rogunavirus genus, comprising a long and non-contractile tail, isolated from bovine feces and shares close genomic evolutionary similarities with Escherichia phages vB_EcoS-BECP10 and bV_EcoS_AKS96. When used against E. coli O157:H7 (ATCC35150), phage UDF157lw exhibited a latent period of 14 min and a burst size of 110 PFU per infected cell. The phage remained viable in a wide range of pH values (pH 4-11) and temperatures (4-60°C). No virulence genes, such as stx, lysogenic genes, and antibiotic resistance genes, were found. Phage UDF157lw demonstrated high infection efficiencies against different E. coli O157:H7 and generic E. coli strains. In addition, UDF157lw encoded a unique major tail protein (ORF_26) with prominent depolymerase enzyme activity against various E. coli O157:H7 strains, causing large plaque sizes. In contrast to the phage without encoding depolymerase gene, UDF157lw was able to reduce the 24-h and 48-h E. coli O157:H7 biofilm after 1-h phage treatment.

Discussion

The findings of this study provide insights into a new member of the Rogunavirus phages and demonstrate its antimicrobial potential against E. coli O157:H7 in vitro.

Phage-Based Biosanitation Strategies for Minimizing Persistent Salmonella and Campylobacter Bacteria in Poultry

Control strategies to minimize pathogenic bacteria in food animal production are one of the key components in ensuring safer food for consumers. The most significant challenges confronting the food industry, particularly in the major poultry and swine sectors, are antibiotic resistance and resistance to cleaning and disinfection in zoonotic bacteria. In this context, bacteriophages have emerged as a promising tool for zoonotic bacteria control in the food industry, from animals and farm facilities to the final product. Phages are viruses that infect bacteria, with several advantages as a biocontrol agent such as high specificity, self-replication, self-limitation, continuous adaptation, low inherent toxicity and easy isolation. Their development as a biocontrol agent is of particular interest, as it would allow the application of a promising and even necessary "green" technology to combat pathogenic bacteria in the environment. However, bacteriophage applications have limitations, including selecting appropriate phages, legal restrictions, purification, dosage determination and bacterial resistance. Overcoming these limitations is crucial to enhance phage therapy's effectiveness against zoonotic bacteria in poultry. Thus, this review aims to provide a comprehensive view of the phage-biosanitation strategies for minimizing persistent Salmonella and Campylobacter bacteria in poultry.

Strategies and materials for the prevention and treatment of biofilms

Biofilms are aggregates of organized microbial growth that function as barriers and create a stable internal environment for cell survival. The bacteria in the biofilms exhibit characteristics that are quite different from the planktonic bacteria, such as strong resistance to antibiotics and other bactericides, getting out of host immunity, and developing in harsh environments, which all contribute to the persistent and intractable treatment. Hence, there is an urgent need to develop novel materials and strategies to combat biofilms. However, most of the reviews on anti-biofilms published in recent years are based on specific fields or materials. Microorganisms are ubiquitous, except in the context of medical and health issues; however, biofilms exert detrimental effects on the advancement and progress of various fields. Therefore, this review aims to provide a comprehensive summary of effective strategies and methodologies applicable across all industries. Firstly, the process of biofilms formation was introduced to enhance our comprehension of the "enemy". Secondly, strategies to intervene in the important links of biofilms formation were discussed, taking timely action during the early weak stages of the "enemy". Thirdly, treatment strategies for mature biofilms were summarized to deal with biofilms that break through the defense line. Finally, several substances with antibacterial properties were presented. The review concludes with the standpoint of the author about potential developments of anti-biofilms strategies. This review may help researchers quickly understand the research progress and challenges in the field of anti-biofilms to design more efficient methods and strategies to combat biofilms.

Migration of surface-associated microbial communities in spaceflight habitats

Astronauts are spending longer periods locked up in ships or stations for scientific and exploration spatial missions. The International Space Station (ISS) has been inhabited continuously for more than 20 years and the duration of space stays by crews could lengthen with the objectives of human presence on the moon and Mars. If the environment of these space habitats is designed for the comfort of astronauts, it is also conducive to other forms of life such as embarked microorganisms. The latter, most often associated with surfaces in the form of biofilm, have been implicated in significant degradation of the functionality of pieces of equipment in space habitats. The most recent research suggests that microgravity could increase the persistence, resistance and virulence of pathogenic microorganisms detected in these communities, endangering the health of astronauts and potentially jeopardizing long-duration manned missions. In this review, we describe the mechanisms and dynamics of installation and propagation of these microbial communities associated with surfaces (spatial migration), as well as long-term processes of adaptation and evolution in these extreme environments (phenotypic and genetic migration), with special reference to human health. We also discuss the means of control envisaged to allow a lasting cohabitation between these vibrant microscopic passengers and the astronauts.

Bacteriophage treatment as an alternative therapy for multidrug-resistant bacteria

Multidrug-resistant (MDR) bacteria constitute one of the most serious global health threats. The increasing incidence rate of bacterial infections caused by MDR strains and the decrease in the number of newly developed antibiotics have prompted the scientific community to search for alternatives. One such alternative is the use of bacteriophages. In this review, we discuss the most critical MDR organisms, including Acinetobacter baumanni, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus The efficacy of phage therapy against MDR bacteria is also discussed. We included studies from the last 10 years that examined the efficacy of phage therapy against MDR pathogens. In addition, this review highlights the effect of bacteriophages against bacterial biofilms. The existing knowledge indicates that phage therapy is a potential therapeutic strategy against MDR bacteria. However, the adverse effects of phage therapy, such as toxicity, and the emergence of phage resistance have not yet been resolved.