Abstract: Olive Quick Decline Syndrome (OQDS) is a severe disease affecting olive trees in southern Italy, for which the causal agent is Xylella fastidiosa subspecies pauca. This bacterium was reported in 2013 and nowadays infects 31 plant species in Apulia region. After the outbreak in Italy, other subspecies and strains of X. fastidiosa were detected in the field in France and Spain. Since the isolation of X. fastidiosa from infected olive plants is relatively less fastidious than from other plant host species, the aim of this study was to isolate the bacterium from different host species using multiple approaches. Isolation of the bacterium was conducted in different periods of the year and was carried out from 29 infected host species. Pure bacterial colonies were obtained only from Olea europaea, Polygala myrtifolia, Nerium oleander and Lavandula angustifolia. Multilocus sequence typing system (MLST) conducted on isolated bacterial colonies from Lavandula angustifola and Polygala myrtifolia showed that the strain infecting both plant species is the same earlier reported from Apulia; De Donno strain.