Control of some septicemic bacterial infections in Oreochromis niloticus, with special reference to their antimicrobial resistant genes.

Abstract

The current study aimed to control the bacterial infection associated with summer mortalities in Nile tilapia. The sensitivity of the isolated bacteria, including Aeromonas Veronii (A. veronii) strain (HY1, HY2, HY3, HY4 and HY6), Citrobacter freundii (C. freundii), Proteus vulgaris (P. vulgaris) and pseudomonas flurosence (P. flurosence) for antibiotic was tested and antibiotic resistant genes were investigated. In order to verify the result of antibiotic sensitivity; experimental trial was performed to determine the effect of florfenicol and erythromycin against Nile tilapia (Oreochromis niloticus) infection with different pathogenic bacteria [4 strains of A. veronii (AHY2), AHY3), AHY4) and AHY6), C. freundii, P. flurosence and P. vulgaris]. The results revealed that all tested bacterial isolates were 100 % sensitive to florfenicol and erythromycin, 50% sensitive to gentamycin, 25 % sensitive to nalidixic acid and sulphamethoxazol-trimethoprim, while all bacterial isolates were 100% resistant to oxytetracycline and tetracycline lincomycin, ofloxacillin and penicillin, 87.5% resistant to ampicillin, 75% resistant to sulphamethoxazol-trimethoprim, 62.5% for nalidixic acid and 37.5% for gentamycin. The relative percent survival (RPS) of challenged medicated fish with erythromycin ranged from 45.0-91.7%. Where, the survival % in HY3 infected groups was the highest (91.7%) followed by C. freundii (87.5%), HY6 (83.3 %) and P. vulgaris (81.3%). Antibiogram profile Antimicrobial resistant gens Bacterial diseasesNile tilapia