Can phage therapy solve the problem of recalcitrant chronic rhinosinusitis?

Case Report: successful use of phage therapy in refractory MRSA chronic rhinosinusitis

We present a case of refractory methicillin-resistant Staphylococcus aureus that was successfully treated with a combination of antibiotics, systemic phage and intranasal phage therapy.

The Potential Role of Bacteriophages in the Treatment of Recalcitrant Chronic Rhinosinusitis

Chronic rhinosinusitis is a common condition affecting 5-12% of the general population worldwide. In a limited number of cases, the disease is recalcitrant to medical and surgical interventions, causing a major impact on physical, social and emotional well-being and increasing pressure on healthcare systems. Biofilm formation and dysbiosis caused by Staphylococcus aureus and Pseudomonas aeruginosa play a role in the pathogenesis of recalcitrant chronic rhinosinusitis. In these cases, a promising treatment alternative is the application of bacteriophages, which are viruses that infect and lyse bacteria. In this review, we appraise the evidence for the use of bacteriophages in the treatment of recalcitrant chronic rhinosinusitis. Additionally, (dis)advantages of bacteriophages and considerations for implementation of phage therapy in otorhinolaryngology practice will be discussed.

Challenging the gold standard: methods of sampling for microbial culture in patients with chronic rhinosinusitis

Purpose

Chronic rhinosinusitis (CRS) is a highly prevalent multifactorial disorder. Culture-directed antibiotics are frequently prescribed to patients with CRS and the middle nasal meatus (MM) is traditionally believed to be a representative sampling site of the sinuses as a whole. The purpose of our study was to reevaluate the reliability of the MM as a sampling site in patients with CRS who suffer from impaired drainage from the sinuses to the MM.

Methods

Swabs and tissue biopsies were collected from the MM, maxillary sinus and frontal sinus from 50 patients with CRS. The results of bacterial culture were compared between sampling methods and sites in relation to the patency of the sinus ostia.

Results

782 bacterial isolates were cultured from the samples. Concordant results between the MM and the sinus cavity were noted in 80% of patients for the maxillary sinus, but only 66% for the frontal sinus and 76% for the sinuses a whole. The differences were similarly prevalent in patients with open and occluded sinus ostia. Notably, swabs from all three sites provided representative information in 92% of patients and tissue biopsies did not provide additional information compared to multiple swabs.

Conclusion

The traditional method of sampling from the middle meatus provides inadequate information in 24% of patients with CRS, which may result in inadequate antibiotic therapy and contribute to increasing antibiotic resistance. Additional sampling from the sinuses should be recommended whenever possible, while invasive sampling is not necessary.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00405-021-06747-z.

Exacerbations of Chronic Rhinosinusitis-Microbiology and Perspectives of Phage Therapy

The chronically inflamed mucosa in patients with chronic rhinosinusitis (CRS) can additionally be infected by bacteria, which results in an acute exacerbation of the disease (AECRS). Currently, AECRS is universally treated with antibiotics following the guidelines for acute bacterial rhinosinusitis (ABRS), as our understanding of its microbiology is insufficient to establish specific treatment recommendations. Unfortunately, antibiotics frequently fail to control the symptoms of AECRS due to biofilm formation, disruption of the natural microbiota, and arising antibiotic resistance. These issues can potentially be addressed by phage therapy. In this study, the endoscopically-guided cultures were postoperatively obtained from 50 patients in order to explore the microbiology of AECRS, evaluate options for antibiotic treatment, and, most importantly, assess a possibility of efficient phage therapy. Staphylococcus aureus and coagulase-negative staphylococci were the most frequently isolated bacteria, followed by Haemophilus influenzae, Pseudomonas aeruginosa, and Enterobacteriaceae. Alarmingly, mechanisms of antibiotic resistance were detected in the isolates from 46% of the patients. Bacteria not sensitive to amoxicillin were carried by 28% of the patients. The lowest rates of resistance were noted for fluoroquinolones and aminoglycosides. Fortunately, 60% of the patients carried bacterial strains that were sensitive to bacteriophages from the Biophage Pharma collection and 81% of the antibiotic-resistant strains turned out to be sensitive to bacteriophages. The results showed that microbiology of AECRS is distinct from ABRS and amoxicillin should not be the antibiotic of first choice. Currently available bacteriophages could be used instead of antibiotics or as an adjunct to antibiotics in the majority of patients with AECRS.

Bacteriophage research - What we have learnt and what still needs to be addressed

Research on bacteriophages has significantly enhanced our understanding of molecular biology, the genomes of prokaryotic cells, and viral ecology. Phages and lysins offer a viable alternative to the declining utility of antibiotics in this post-antibiotic era. They also provide ideal teaching tools for genomics and bioinformatics. This article touches on the first 100 years of phage research with the author commenting on what he thinks are the highlights, and what needs to be addressed.

A CRISPR-Cas9-Based Toolkit for Fast and Precise In Vivo Genetic Engineering of Bacillus subtilis Phages

Phages are currently under discussion as a solution for the antibiotic crisis, as they may cure diseases caused by multi-drug-resistant pathogens. However, knowledge of phage biology and genetics is limited, which impedes risk assessment of therapeutic applications. In order to enable advances in phage genetic research, the aim of this work was to create a toolkit for simple and fast genetic engineering of phages recruiting Bacillus subtilis as host system. The model organism B. subtilis represents a non-pathogenic surrogate of its harmful relatives, such as Bacillus anthracis or Bacillus cereus. This toolkit comprises the application CutSPR, a bioinformatic tool for rapid primer design, and facilitates the cloning of specific CRISPR-Cas9-based mutagenesis plasmids. The employment of the prophage-free and super-competent B. subtilis TS01 strain enables an easy and fast introduction of specific constructs for in vivo phage mutagenesis. Clean gene deletions and a functional clean gene insertion into the genome of the model phage vB_BsuP-Goe1 served as proof of concept and demonstrate reliability and high efficiency. The here presented toolkit allows comprehensive investigation of the diverse phage genetic pool, a better understanding of phage biology, and safe phage applications.