Biology subjects

Kadouri, D. E.

Publications and source records attributed to Kadouri, D. E..

3 recordsLinked to original sources

bioRxiv2023

Intra-ocular Predation of Fluoroquinolone-Resistant Pseudomonas aeruginosa and Serratia marcescens by the Predatory Bacteria

Endogenous endophthalmitis caused by Gram-negative bacteria is an intra-ocular infection that can rapidly progress to irreversible loss of vision. While most endophthalmitis isolates are susceptible to antibiotic therapy, the emergence of resistant bacteria necessitates alternative approaches to combat intraocular bacterial proliferation. In this study the ability of predatory bacteria to limit intraocular growth of Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus aureus was evaluated in a New Zealand White rabbit endophthalmitis prevention model. Predatory bacteria Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus were able to reduce proliferation of keratitis isolates of P. aeruginosa and S. marcescens. However, it was not able to significantly reduce S. aureus, which is not a productive prey for these predatory bacteria, suggesting that the inhibitory effect on P. aeruginosa requires active predation rather than an antimicrobial immune response. Similarly, UV-inactivated B. bacteriovorus were unable to prevent proliferation of P. aeruginosa. Together, these data suggest in vivo predation of Gram-negative bacteria within the intra-ocular environment.

microbiology↗

bioRxiv2023

Predatory Bacteria can Reduce Pseudomonas aeruginosa Induced Corneal Perforation and Proliferation in a Rabbit Keratitis Model

PurposePseudomonas aeruginosa keratitis is a severe ocular infection that can lead to perforation of the cornea. In this study we evaluated the role of bacterial quorum sensing in generating corneal perforation and bacterial proliferation and tested whether co-injection of the predatory bacteria Bdellovibrio bacteriovorus could alter the clinical outcome. P. aeruginosa with lasR mutations were observed among keratitis isolates from a study collecting samples from India, so an isogenic lasR mutant strain of P. aeruginosa was included. MethodsRabbit corneas were intracorneally infected with P. aeruginosa strain PA14 or an isogenic {Delta}lasR mutant and co-injected with PBS or B. bacteriovorus. After 24 h, eyes were evaluated for clinical signs of infection. Samples were analyzed by scanning electron microscopy, optical coherence tomography, sectioned for histology, and corneas were homogenized for CFU enumeration and for inflammatory cytokines. ResultsWe observed that 54% of corneas infected by wild-type PA14 presented with a corneal perforation (n=24), whereas only 4% of PA14 infected corneas that were co-infected with B. bacteriovorus perforate (n=25). Wild-type P. aeruginosa proliferation was reduced 7-fold in the predatory bacteria treated eyes. The {Delta}lasR mutant was less able to proliferate compared to the wild-type, but was largely unaffected by B. bacteriovorus. ConclusionThese studies indicate a role for bacterial quorum sensing in the ability of P. aeruginosa to proliferate and cause perforation of the rabbit cornea. Additionally, this study suggests that predatory bacteria can reduce the virulence of P. aeruginosa in an ocular prophylaxis model.

microbiology↗

bioRxiv2022

Breakdown of cooperative architecture in dual species biofilms and the spatial ecology of predation

Adherence to surfaces and secretion of extracellular matrix, or biofilm formation, is common in the microbial world, but we often do not know how interaction at the cellular spatial scale translates to higher-order biofilm community ecology. Here we explore an especially understudied element of biofilm ecology, namely predation by the bacterium Bdellovibrio bacteriovorus. This predator can kill and consume many different Gram-negative bacteria, including Vibrio cholerae and Escherichia coli. V. cholerae can protect itself from predation within highly packed biofilm structures that it creates, whereas E. coli biofilms are highly susceptible to B. bacteriovorus. Here we explore how predator-prey dynamics change when V. cholerae and E. coli are growing in biofilms together. We find that in dual species prey biofilms, E. coli survival under B. bacteriovorus predation increases, whereas V. cholerae survival decreases. E. coli benefits from predator protection when it becomes embedded within expanding groups of highly packed V. cholerae. But we also find that the ordered, highly packed, and clonal biofilm structure of V. cholerae can be disrupted if V. cholerae cells are directly adjacent to E. coli cells at the start of biofilm growth. When this occurs, the two species become entangled, and the resulting disordered cell groups do not block predator entry. Because biofilm cell group structure depends on initial cell distributions at the start of prey biofilm growth, the colonization dynamics have a dramatic impact on the eventual multispecies biofilm architecture, which in turn determines to what extent both species survive exposure to B. bacteriovorus. Significance StatementBacteria live in multispecies, spatially structured communities ubiquitously in the natural world. These communities, or biofilms, have a strong impact on microbial ecology, but we often do not know how cellular scale interactions determine overall biofilm structure and community dynamics. Here we explore this problem in the context of predator-prey interaction, with two prey species - Vibrio cholerae and Escherichia coli - being attacked by the bacterial predator Bdellovibrio bacteriovorus. We find that when V. cholerae and E. coli grow together in biofilms, the architectures that they both produce change in ways that cannot be predicted from looking at each prey species alone, and that these changes in cell group structure impact the community dynamics of predator-prey interaction in biofilms.

microbiology↗