325 Bulletin UASVM, Veterinary Medicine 66(1)/2009 ISSN 1843-5270; Electronic ISSN 1843-5378 The Sensitivity of Psittacine Isolated Pseudomonas Strains towards Antibiotics Anca OPREA, Maria CRIVINEANU, LaurenŃiu TUDOR, Iulian łOGOE University of Agronomical Sciences and Veterinary Medicine Bucharest, Faculty of Veterinary Medicine, 105 Splaiul Independentei, District 5, Bucharest, donlorenzofmv@yahoo.com Abstract. Avian Pseudomonas disease evolves in an acute or chronic form on cage birds and involves difficulties concerning establishing an optimal therapeutical conduct. Due to the risk of transmission to other individuals, and also to the personnel involved directly in care and treatment of ill animals, it is very important to rapidly institute an adequate therapy in order to assure the rapid limitation of pseudomonads transmission to humans or other animals. These facts constitute the base of the initialization of different studies on some different Pseudomonas spp. strains sensitivity, these being isolated from several clinical aviary cases (especially psittacines), in comparison to the different groups and types of antibiotics used currently in the treatment scheme of birds. Considering the investigations performed, the conclusion is that, even though the latest cephalosporins and fluoroquinolons have a maximum efficiency towards some of the strains, these registered also the antibiotic resistance phenomenon, in a strong proportion (41,8 to 94,12 % from the tested strains). There have been obtained constant results considering streptomycin, azithromycin, amoxicillin, associated with clavulanic acid, doxicycline and tetracycline. Keywords: Pseudomonas, psittacines, antibiotics, therapy INTRODUCTION From opportunist Gram-negative bacteria, Pseudomonas aeruginosa represents a very important concern for pathology, due to its ubiquitary distribution, and also the various and numerous mechanisms of pathogenity, which allow it to produce a large gamut of primary and secondary infections, with anathomic and clinical manifestations of high diversity in humans and animals. The fact that this bacterium is present in the water, soil, on the surface of the plants, in the organisms of insects or human one and of different animals species in considerable quantities, under the shape of a colony included in a carbohydrates mass, with fibrillar aspect, explains why, especially in stress conditions or after the long application of antibiotic treatments, this bacterium is rapidly multiplying, determining pathological processes in minor resistance spots of different tissues. There has been demonstrated that this bacterium possesses several structures or it elaborates during its metabolism numerous substances able to produce the deep alteration of the normal functions of the organism (tissues). The structures on the surface of the bacterial cell (pili, surface carbohydrates, lipopolyglucids from the cell wall) are the main determining agents of virulence. But the bacterium elaborates also some toxic substances as: exotoxin A, proteases, lecitinases and endotoxins, which determine irreversible lesions in different types of tissues. If it is considered the limited possibilities to treat the infections that this bacterial species determines in humans and animals, due to a small number of active antibiotics for this bacterium, the relative high rate of mutation towards the antibiotic resistance and of rapid selection