# Bdellovibrio bacteriovorus: mechanisms, problems, and prospects against MDR respiratory infections

## TL;DR

Bdellovibrio bacteriovorus, a predatory bacterium, shows promise in fighting antibiotic-resistant respiratory infections by targeting harmful bacteria like Klebsiella and Pseudomonas.

## Contribution

This review explores the potential of B. bacteriovorus against MDR respiratory infections and highlights its mechanisms and limitations.

## Key findings

- Intranasal administration of B. bacteriovorus reduces Klebsiella pneumoniae lung burden in rat models by more than 3 log10.
- B. bacteriovorus disrupts Pseudomonas aeruginosa biofilms and reduces epithelial invasion in vitro.
- B. bacteriovorus primarily targets Gram-negative bacteria and biofilm-forming species but has limited effectiveness against Gram-positive bacteria.

## Abstract

The rising rate of multidrug resistance (MDR) among bacteria is a real threat to public health across the globe, necessitating novel solutions that are beyond pharmacological approaches. The appearance of Bdellovibrio bacteriovorus as a predatory Gram-negative bacterium has become an alternative source to treat antibiotic-resistant infections, especially in cases of respiratory tract infections by pathogenic organisms like Klebsiella pneumoniae and Pseudomonas aeruginosa. In vivo studies demonstrate that intranasal administration of Bdellovibrio bacteriovorus reduces Klebsiella pneumoniae lung burden by more than 3 log10 in rat models, while in vitro studies report significant disruption of P. aeruginosa biofilms and reduced epithelial invasion. The targeting of Gram-negative bacteria by this bacterium is the key to success, as this bacterium can prey upon Gram-negative bacteria and biofilm-forming bacteria. Nonetheless, Gram-positive bacteria have not been fully utilized in the application of Bdellovibrio bacteriovorus. In this review, our study aims to discuss antibiotic resistance, the Bdellovibrio life cycle, Bdellovibrio bacteriovorus against Gram-negative and Gram-positive bacteria, its shortcomings, and the way it could be applied, most especially against respiratory infections. However, important limitations remain, including incomplete eradication of prey populations, transient phenotypic resistance, and the absence of long-term or human clinical safety data. This review highlights the potential of B. bacteriovorus as an active antibacterial agent and draws attention to its clinical use to solve the current MDR respiratory infections.