Comprehensive Assessment of Bacterial Diseases in the Shrimp: Clinical, Phenotypic, Genotypic, and Histopathological Approaches

This study was conducted to investigate bacterial pathogens related to diseases in shrimp and their associated alterations. A total of 80 live adult Penaeid shrimps, including Penaeus japonicus, Litopenaeus vannamei, and Penaeus semisulcatus, with average body weight and length of 32± 3g and 14.5± 2cm, respectively, were randomly collected from fishermen in Suez Province, Egypt. The collected shrimp samples underwent comprehensive clinical, postmortem, bacteriological, and histopathological examinations. Moreover, antimicrobial profiling of the recovered bacterial isolates was conducted. PCR-based methods were also applied to shrimp tissues to identify bacterial pathogens. Clinically, affected shrimp displayed symptoms including red discoloration, soft exoskeleton, and brown to black or white spots on various body parts. Bacteriological analysis revealed the isolation and identification of Vibrio, Pseudomonas, and Aeromonas species, with Vibrio being the most prevalent (82.5%), followed by Pseudomonas (78.75%), and Aeromonas species (42.5%). The hepatopancreas was identified as the most affected organ. Antibiotic susceptibility of bacterial isolates showed high susceptibility to gentamicin, trimethoprim/sulfamethoxazole and tetracycline among the recovered bacterial isolates. Moreover, analysis of 16S rRNA, PA-GS, and Aer genes (species- specific genes) confirmed the presence of these species within shrimp tissues, with Vibrio species being the most dominant. Histopathological examination revealed degenerative changes in muscle, hepatopancreas, and uropods, accompanied by edema and hemocytic influx throughout the infected tissues. In conclusion, applying molecular techniques is the most precise and rapid method to diagnose bacterial pathogens in shrimp tissues, which is an essential step for ensuring sustainability in the shrimp industry.