ECOLOGICAL RELATIONSHIP BETWEEN AEROMONAS AND VIBRIO SPP AND PLANKTONIC COPEPODS IN THE COASTAL MARINE-ENVIRONMENT IN SOUTHERN ITALY

The colonisation of planktonic copepod integument by bacteria belongin g to the family of Vibrionaceae is a well described phenomenon. In thi s study, besides reporting on the occurrence of Vibrionaceae and other enteropathogens, we further report on the bacterial attachment to the Estuarine copepod Acartia margalefi in a faecal polluted coastal lago on near Naples, Southern Italy. In addition, we also performed a labor atory experiment to study the ability of 7 bacterial strains (Vibrio c holerae non-Ol, V. mimicus, V. parahaemolyticus, V. alginolyticus, Aer omonas hydrophila, Escherichia coli and Pseudomonas sp.) to colonise t he copepod integument. For this laboratory study, 4 different species of copepods, namely Temora stylifera, A. clausi, Centropages typicus a nd Paracalanus parvus sampled from the Gulf of Naples (Southern Italy) were used. Scanning electron microscope (SEM) studies on the copepods sampled from the lagoon indicated that the bacterial attachment on th e integument of Acartia margalefi was mainly on the ventro-lateral bod y region of the host and in the joints of the thoracic segments, as we ll as on the swimming and feeding appendages. This infestation, made b y rod-like bacteria, was absent in winter but reached peak values of 7 0% frequency in June. The laboratory studies showed that while V. chol erae non-Ol and A. hydrophila attached on live and dead copepods, resp ectively, the V. parahaemolyticus, V. alginolyticus, V. mimicus, E. co li and Pseudomonas sp. failed to colonise either live or dead copepods . Thus, this study provides further valuable information about the eco logical relationship between different microorganisms (pathogens) and copepods in the coastal marine environment in Southern Italy. Copyrigh t (C) 1996 Elsevier Science Ltd