Advances in bacteriophage-mediated strategies for combating polymicrobial biofilms

Isolation and characterization of a broad-spectrum bacteriophage against multi-drug resistant Escherichia coli from waterfowl field

Escherichia coli (E. coli) is a significant pathogen responsible for intestinal infections and foodborne diseases. The rise of antibiotic resistance poses a significant challenge to global public health. Traditional antibiotic therapy is becoming increasingly ineffective, highlighting the urgent need for innovative control strategies. This study explores the potential of bacteriophages as a sustainable alternative to traditional antibiotics. From 2021 to 2022, a total of 183 non-repetitive duck source fecal samples were collected from Mianyang City, Sichuan Province, and 126 strains of E. coli were isolated. The minimum inhibitory concentration (MIC) test showed that these strains exhibited high resistance to piperacillin (96.8%), tetracycline (88.9%), and chloramphenicol (86.5%). It is concerning that 93.7% of the isolates are classified as multidrug-resistant (MDR), posing a significant threat to existing treatment options. 20 bacteriophages were isolated from fecal and soil samples, among which 5 bacteriophages were selected for further analysis. Bacteriophage YP6 showed excellent lytic effects on MDR strains, especially strain MY104, as well as representative serotypes O1 (E. coli MY51) and O18 (E. coli MY106). The identification of YP6 as a member of the Myoviridae family was conducted using transmission electron microscopy, and it was found to have an optimal infection factor of 0.1. Bacteriophages exhibit significant thermal and pH stability, maintaining survival at temperatures up to 60 °C and pH ranges of 4 to 10. Whole genome sequencing confirmed that YP6 has a double stranded DNA genome of 139,323 base pairs (bp), and no antibiotic resistance or virulence genes were found, indicating a low possibility of horizontal gene transfer. In addition, YP6 effectively inhibits the formation of E. coli biofilm, which is a key factor in chronic infections. The in vivo experiments using Galleria mellonella (G. mellonella) larvae have shown that it has a significant protective effect against MDR E. coli infection. In summary, bacteriophage YP6 is expected to become a therapeutic agent against MDR E. coli infection due to its broad host range, environmental stability, and biofilm inhibition properties. Future research should optimize bacteriophage preparations, evaluate the safety and efficacy of animal models, and establish clinical application plans in the field of food safety.

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.

"Stop, Little Pot" as the Motto of Suppressive Management of Various Microbial Consortia

The unresolved challenges in the development of highly efficient, stable and controlled synthetic microbial consortia, as well as the use of natural consortia, are very attractive for science and technology. However, the consortia management should be done with the knowledge of how not only to accelerate but also stop the action of such "little pots". Moreover, there are a lot of microbial consortia, the activity of which should be suppressively controlled. The processes, catalyzed by various microorganisms being in complex consortia which should be slowed down or completely cancelled, are typical for the environment (biocorrosion, landfill gas accumulation, biodegradation of building materials, water sources deterioration etc.), industry (food and biotechnological production), medical practice (vaginitis, cystitis, intestinal dysbiosis, etc.). The search for ways to suppress the functioning of heterogeneous consortia in each of these areas is relevant. The purpose of this review is to summarize the general trends in these studies regarding the targets and new means of influence used. The analysis of the features of the applied approaches to solving the main problem confirms the possibility of obtaining a combined effect, as well as selective influence on individual components of the consortia. Of particular interest is the role of viruses in suppressing the functioning of microbial consortia of different compositions.

Gut phageome: challenges in research and impact on human microbiota

The human gut microbiome plays a critical role in maintaining our health. Fluctuations in the diversity and structure of the gut microbiota have been implicated in the pathogenesis of several metabolic and inflammatory conditions. Dietary patterns, medication, smoking, alcohol consumption, and physical activity can all influence the abundance of different types of microbiota in the gut, which in turn can affect the health of individuals. Intestinal phages are an essential component of the gut microbiome, but most studies predominantly focus on the structure and dynamics of gut bacteria while neglecting the role of phages in shaping the gut microbiome. As bacteria-killing viruses, the distribution of bacteriophages in the intestine, their role in influencing the intestinal microbiota, and their mechanisms of action remain elusive. Herein, we present an overview of the current knowledge of gut phages, their lifestyles, identification, and potential impact on the gut microbiota.

Stability study in selected conditions and biofilm-reducing activity of phages active against drug-resistant Acinetobacter baumannii

Acinetobacter baumannii is currently a serious threat to human health, especially to people with immunodeficiency as well as patients with prolonged hospital stays and those undergoing invasive medical procedures. The ever-increasing percentage of strains characterized by multidrug resistance to widely used antibiotics and their ability to form biofilms make it difficult to fight infections with traditional antibiotic therapy. In view of the above, phage therapy seems to be extremely attractive. Therefore, phages with good storage stability are recommended for therapeutic purposes. In this work, we present the results of studies on the stability of 12 phages specific for A. baumannii under different conditions (including temperature, different pH values, commercially available disinfectants, essential oils, and surfactants) and in the urine of patients with urinary tract infections (UTIs). Based on our long-term stability studies, the most optimal storage method for the A. baumannii phage turned out to be - 70 °C. In contrast, 60 °C caused a significant decrease in phage activity after 1 h of incubation. The tested phages were the most stable at a pH from 7.0 to 9.0, with the most inactivating pH being strongly acidic. Interestingly, ethanol-based disinfectants caused a significant decrease in phage titers even after 30 s of incubation. Moreover, copper and silver nanoparticle solutions also caused a decrease in phage titers (which was statistically significant, except for the Acba_3 phage incubated in silver solution), but to a much lesser extent than disinfectants. However, bacteriophages incubated for 24 h in essential oils (cinnamon and eucalyptus) can be considered stable.