Characterization of a Unique Bordetella bronchiseptica vB_BbrP_BB8 Bacteriophage and Its Application as an Antibacterial Agent

Mateusz Szymczak,Jarosław Adam Pankowski,Paweł Bącal,Hanna Országh-Szturo,Joanna Karczewska-Golec,Bartłomiej Grygorcewicz,Piotr Golec,Przemysław Decewicz,Barbara Dołęgowska

doi:10.3390/ijms21041403

Abstract

Bordetella bronchiseptica, an emerging zoonotic pathogen, infects a broad range of mammalian hosts. B. bronchiseptica-associated atrophic rhinitis incurs substantial losses to the pig breeding industry. The true burden of human disease caused by B. bronchiseptica is unknown, but it has been postulated that some hypervirulent B. bronchiseptica isolates may be responsible for undiagnosed respiratory infections in humans. B. bronchiseptica was shown to acquire antibiotic resistance genes from other bacterial genera, especially Escherichia coli. Here, we present a new B. bronchiseptica lytic bacteriophage—vB_BbrP_BB8—of the Podoviridae family, which offers a safe alternative to antibiotic treatment of B. bronchiseptica infections. We explored the phage at the level of genome, physiology, morphology, and infection kinetics. Its therapeutic potential was investigated in biofilms and in an in vivo Galleria mellonella model, both of which mimic the natural environment of infection. The BB8 is a unique phage with a genome structure resembling that of T7-like phages. Its latent period is 75 ± 5 min and its burst size is 88 ± 10 phages. The BB8 infection causes complete lysis of B. bronchiseptica cultures irrespective of the MOI used. The phage efficiently removes bacterial biofilm and prevents the lethality induced by B. bronchiseptica in G. mellonella honeycomb moth larvae.

Highlights

Bordetella bronchiseptica is a Gram-negative coccobacilli-shaped bacterium capable of colonizing the respiratory track of mammalian hosts, primarily farm, wild, and companion animals [1]
During the host range analysis, we investigated more than 20 animal isolates of Klebsiella spp., Acinetobacter spp., Enterobacter cloacae, and Escherichia coli
In humans the actual burden of diseases caused by B. bronchiseptica is unknown, but it has been postulated that B. bronchiseptica infections are more common than previously appreciated, and that some hypervirulent isolates may be responsible for undiagnosed respiratory infections [26]

Summary

Introduction

Bordetella bronchiseptica is a Gram-negative coccobacilli-shaped bacterium capable of colonizing the respiratory track of mammalian hosts, primarily farm, wild, and companion animals [1]. The bacterium is a common etiological agent of tracheobronchitis, conjunctivitis, rhinitis, mandibular lymphadenopathy, and pneumonia [2]. Its effect tends to be most prominent in tightly packed areas, such as shelters, households, or intensive piggery systems [2]. Dogs suffering from B. bronchiseptica-associated kennel cough can pass the pathogen to cats [3]. Zoonotic transfer to humans is possible, albeit rarely reported [4]. The majority of the reported cases included immunocompromised individuals, such as transplant recipients, HIV-infected patients or those with a history of malignancy [5,6,7]

Methods

Discussion

Conclusion