Isolation and treatments of Aeromonas hydrophila and Staphylococcus lentus implicated in the seasonal autumn mortalities of farm-raised Cyprinus carpio, Basrah governorate, Iraq
Authors: Aziz Bannai Majid Abdul , Kenani Abdul Jabbar K.A. , Al Shammari Nadia A. H. , Al-Nagar Ghassan , Mustafa Fawzi 
Published: November 2020

Abstract
Aeromonas hydrophila and Staphylococcus lentus are a widespread bacterial species in the aquatic environment, isolate from different aquatic environments, and it is a responsible for bacterial disease of Hemorrhagic Septicemia in freshwater fish, in addition to other species. Furthermore, the main reason for its spread is not following proper farming systems and food quality and lack of oxygen and intensive farming play a key in the spread of this type of bacterial. The presence of bacteria as a real indicator of severe water contamination and this underlines the presence of high numbers of fish mortalities domain as accompanies this shortage pollution biomarkers of fish including dissolved oxygen and this has been confirmed by many international studies which the most important. The samples were collected from the common carp farms north of Basrah city. A total of 30 live infected fishes was collected, during the autumn season of the year 2019, samples were placed in ice box and transferred to the laboratory of department marine vertebrate marine science center and to Al Noor vet. lab. Within 3hrs. Fish weights and lengths from l50 -350 gm, and 15-35cm respectively. Bacterial samples were taken from the skin, gills and intestines using a sterile scalpel, samples were homogenized in 9 ml of sterile normal saline solution, one milliliter aliquots of the homogeneous solutions were serially diluted (10-1 to 10-7), aliquots of 0.1 ml of the serial dilutions were inoculated on tryptic soya agar (TSA) (Hi media- India). Nutrient agar (Hi media- India) in duplicate using the spread plate method and the plates were incubated at 37°C for 24-48 h. Then after, Bacteria were identified using the VITEK II system. The bacterial sensitivity testing used following Bauer method, through the use of a sterile swab of vaccination on a predefined inoculate a plate of Mueller Hinton agar. Within 30 minutes of applying the discs, invert the plate and incubate it aerobically at 35 C for 24 h (temperatures over 35 C). After overnight incubation, using a ruler on the underside of the plate measure the diameter of each zone of inhibition in mm. The endpoint of inhibition is where growth starts. Five antibiotics used in the study were: ampicillin 20mg (Amp), Erythromycin 15 mg (Eritrea), Florfenicol 10 mg (Flo), Enofloxacin 10mg (Eno), Neomycin 30mg (Neo). The amount of processed fish for therapeutic course treatment was 2000 fish which kept in a clay bottom pond with size of 100x 10 m, with depth 2 m. The treatments were done by adding 10% concentration of Enrofloxacin in fish feed directly with ratio with a percentage of 15 mg/kg of cultures fish for five days. The current study included isolating and treating of two species of bacterial, Aeromonas hydrophila with probability (98%) and Staphylococcus lentus (90%), were implicated in the seasonal autumn mortalities of farm-raised Cyprinus carpio, Basrah Governorates, Iraq. Infected fishes were collected, have increased in the mortality rate and suffering from skin necrosis, hemorrhage and acute infections during the autumn season of the year 2019, the swabs were taken from the skin, gills and intestine. Bacterial strains were identified using the VITEK ii system. The sensitive antibiotic test was applied using Muller Hintom agar manufactured India, five antibiotics were used: Ampicillin 20mg (Amp), Erythromycin 15 mg (Eritrea), Florfenicol 10 mg (Flo), Enofloxacin 10mg (Eno) and Neomycin 30mg (Neo). Therapeutic course treatment was used 2000 aquaculture fish, therapeutic course treatment was used in 100 x 10 meters with depth 2 meters’ pond using 10% concentration of enrofloxacin therapy, the results indicated that a remarkable decrease in morbidity and mortality, and contributing to important progresses in the health of the fish population leading to a dramatic reduction in morbidity and mortality, and contributing to significant advances in the health of the general population also results of the study suggest that the enrofloxacin therapy could be potential therapeutic options for treating septic wounds caused by above mentioned bacterial. The results of the study suggest that the both bacterial species are very influential pathogens in aquaculture operations, cause high mortality in cultured ponds. The requires making with correct treatments in a short time, use of antibiotics after allergy testing can lead to very fast solutions and treatments can control these diseases in commitment right help. The uses of enrofloxacin therapy treatment is the first attempts in the world to treat fish diseases, where it is intended for poultry diseases. Antibiotics should not use as an easy alternative by farmers in person without adequate diagnosis of medical condition to fish farming practices. Health organizations in relevant institutions must follow strict programs to using antibiotics to residual products environment of antimicrobials in aquaculture production. Control programs must undergo treatment exchange views to surveillance under the grant or authorization in using antibiotic at the national level is the latest legislation and standards based on sound science.