Recent years have observed an alarming increase on bacterial resistance
to antibiotics. Many factors contribute to this, mainly antibiotics misuse
but also an intrinsic capacity of bacteria to trade genetic material. These
exchanges are emphasized in biofilms due to bacteria proximity, and
involve several mechanisms including prophage-mediated transduction.
Prophages are bacteriophages that incorporate into the bacterial
genome, being able to excise and enter other bacteria. They are found in
many bacterial species, being particularly frequent in Acinetobacter
baumannii. This bacterial species is emerging as an important
nosocomial pathogen worldwide especially due to a rapid acquisition of
antibiotic resistance, in which prophage-mediated transduction may play
a key role.The aim of this work was to evaluate the role of prophages on
virulence transduction in A. baumannii biofilms. For this, an A. baumannii
strain (ANC 4097) enclosing a prophage codifying a beta-lactam
resistance gene and a receptor A. baumannii strain (NIPH 146) were
selected based on biofilm-forming capacity. Strain susceptibility was
tested for selecting a beta-lactam antibiotic to assess transduction. Both
strains were genetically modified to follow transduction by fluorescence
microscopy (mCherry inserted in the prophage and gfp in 146) and 146
was further modified to allow strain distinction on plate (lacZ). Levels of
transduction were evaluated in mixed biofilms under different stress
conditions (sub-MIC, light, and temperature).This work provides new
insights into the importance of prophage transduction in virulence
acquisition in mixed A. baumannii biofilms
