Intraspecific characterization of Vibrio alginolyticus isolates recovered from aquaculture systems and marine biotopes in Tunisia by PCR-RFLP, ECP and OMPs profiling

A total of 54 presumptive Vibrio alginolyticus strains isolated from a variety of Tunisian marine biotopes, such as seawater, sediment samples from some bathing areas, and aquaculture farms, were characterized and identified by several biochemical tests. DNA polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, extracellular products (ECP) and outer membrane protein (OMP) profiling were used to evaluate their usefulness as a tool to investigate the Vibrio alginolyticus diversity within this complex group. Results showed that there is great heterogeneity in the diversity observed via the PCR-RFLP method related to the number of genotypes generated by the two enzymes SduI and FaqI tested. This heterogeneity was observed not only according to the origin (seawater, sediment, fish and bivalve aquaculture farms) but also within the same type of sample. The two other methods, ECP and OMP resulted in 32 and 26 profiles, respectively. The discriminatory index determined in this study highlighted the good ability of the PCR-RFLP method to discriminate similar V. alginolyticus strains. Ukupno 54 vjerojatna soja Vibrio alginolyticus izolirana su iz raznih morskih biotopa u Tunisu, iz morske vode i sedimenta s nekoliko kupališta i uzgajališta te su karakterizirani i identificirani pomoću nekoliko biokemijskih testova. Istraživana je prikladnost metoda kao što su analiza polimorfizma duljine restrikcijskih fragmenata PCR proizvoda (PCR-RFLP), profiliranje izvanstaničnih proizvoda (ECP) i proteina vanjske membrane (OMP) kao alata za istraživanje raznolikosti Vibrio alginolyticus unutar ove složene skupine. Rezultati su pokazali da postoji velika heterogenost u raznolikosti određenoj metodom PCR-RFLP koja se odnosila na broj genotipova generiranih s dva testirana enzima SduI i FaqI . Ova heterogenost je uočena ne samo prema podrijetlu (morska voda, sediment, uzgajališta riba i školjkaša), već i unutar istog tipa uzorka. Druge dvije metode, ECP i OMP rezultirale su s 32, odnosno 26 profila. Indeks diskriminacije utvrđen u ovoj studiji istaknuo je dobru sposobnost PCR-RFLP metode u razlikovanju sličnih sojeva V. alginolyticus .