This preliminary investigation examined the bacteriological profile of blue crab (Callinectes sapidus) haemolymph to identify potential pathogens and evaluate their impact on marine ecosystems. Haemolymph samples were collected from blue crabs in the Northern Adriatic Sea (Italy), with analyses conducted on specimens categorized by carapace length (small: 51-99 mm and large: ≥100 mm). Additionally, seawater samples from the collection site were analysed to assess the bacterial communities present in the surrounding environment. Bacteriological assessments were carried out using various culture media, MALDI-TOF MS, molecular identification based on the rpoB gene, and antibiotic susceptibility testing (Kirby-Bauer method).
The results indicated a diverse array of bacterial species, predominantly Vibrio spp., some of which displayed resistance to antibiotics. In particular, the Vibrio species found in the blue crabs were similar to those identified in the adjacent seawater, emphasizing the direct ecological relationship between the two environments. These findings highlight the necessity of monitoring bacterial pathogens in blue crab populations, particularly given their invasive nature and the considerable ecological and economic impacts they have inflicted in the Adriatic region.
This results are critical for formulating effective management strategies to control the dissemination of pathogens and preserve the health of marine ecosystems. Understanding the bacterial composition of blue crab haemolymph will help address the challenges posed by this invasive species, contributing to the sustainability of blue crab fisheries and the protection of marine biodiversity.