Some studies on pathogenic lactobacillus species in oreochromis aureus

الملخص EN

Lactobacillus species and Pseudomonas florescence were isolated from naturally infected Oreochromis aureus transported from earthen ponds to aquaria.

The naturally infected Oreochromis aureus suffered from dark coloration, ulcers and eye cataract.

Lactobacillus species was examined for its pathogenicity through I/P inoculation.

Hysteric movement and darkness before death were the most common signs.

The postmortem lesions were hemorrhages on liver, kidney and congested intestine with dose 0.4 ml of bacterial suspension containing approximately (4x108 cells/ml) of 24 hours viable bacteria of Lactobacillus species, the mortality rate was 40%, while it was 100% at the double bacterial dose.

At the I/M inoculation site hemorrhages was occurred, erection of scales and development of ulcers.

The postmortem examination showed hemorrhagic liver, pale kidneys and darkness spleen.

The mortality rate was 20% at dose 0.4 ml of bacterial suspension containing approximately (4x108 cells/ml) of 24 hours viable bacteria of Lactobacillus species and 100% at the double bacterial dose.

By skin scarification the fish suffered from dark and the mortality rate was 40%.

Lactobacillus species appeared to be sensitive to Kanamycin, Streptomycin, Triemthoprium and sulfamexazol while Ciproflocacin and resistant to Amoxicillin and Chloramphenicol.