Aquaculture has experienced global growth with a rise in global tilapia output throughout the decades. Aquaculture production fell dramatically from 4.6% in 2018 to 2.3 % in 2019. Disease outbreaks linked to intensive production practices have cost the industry more than $6 billion per year, making them the most expensive risk on farms. In tilapia farming, the majority of bacterial infections are a significant problem, accounting for 80% of fish mortality.
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Ghana had a serious production mishap in 2018, with high fish mortality on Lake Volta. Bacteria pathogens like Streptococcus agalactiae and the Infectious Spleen Necrosis Virus (ISKNV) were the main etiological agents. The unusual patterns of very high fish mortalities (sometimes >70% stock) have collapsed several small and medium-scale fish farms leading to supply shortages and price hikes for cultured fish.
The surge of the disease outbreak allowed most farmers to resort to the use of antibiotics in aquaculture farms and hatcheries to combat both Gram-positive and Gram-negative bacteria pathogens of economic interest. In view of that, oxytetracycline, tetracycline, and erythromycin are the three commonly used antibiotics in aquaculture because of their broad-spectrum activity as a protein synthesis inhibitor against both Gram-positive and Gram-negative bacteria, cost-effectiveness and easy accessibility.
Continuous use of antibiotics promotes the growth of antibiotic microbial resistance (AMR), which places selective pressure on Nile tilapia and the aquatic environment. This demonstrates that the majority of bacteria isolates are now resistant to antibiotic treatments, hence giving antibiotics to Nile tilapia no longer has any significant effects on bacteria. As a result, administering antibiotics to Nile tilapia had no discernible effect on the bacterial pathogens, proving that most of the harmful bacteria are currently resistant to antibiotic treatments.
Bacteria can become resistant to antibiotics through drug inactivation or modification, modification of the drug target site, modification of the metabolic pathways to counteract the effects of the drug, and inhibiting entry and promoting active efflux of the drugs. For this reason, profiling of antibiotic susceptibility testing using the Kirby Bauer disk diffusion method is used to determine the efficacy of a drug against a bacterium and to choose the most effective course of action to treat the disease.
Specific Problem
The widespread and inappropriate utilization of antibiotics such as oxytetracycline and tetracycline has been severely criticized for their side effects such as residual build-up in tissue, drug resistance, and immunological suppression, leading to a drop-in customer desire for antibiotic-treated food fish. Antibiotic residues cause allergic reactions, and toxicity, and change the microflora of the aquatic environment. Oxytetracycline resistance by bacteria has altered the gut microbiome's commensal relationship with Nile tilapia by affecting the physiology of Nile tilapia microbial-mediated functions such as resistance against disease, growth, and metabolism.
The rapid emergence of antibiotic resistance has become a looming public health crisis that causes allergic hypersensitivity reactions or toxic effects. Autoimmunity, ulcerative colitis, and reproductive issues are all human nervous system effects associated with antibiotic resistance from fish. Penicillin triggers allergic reactions and oxytetracycline have immunopathological effects in addition to being carcinogenic.
REASON FOR STRINGENT MEASURES
There is a paucity of knowledge regarding the biomonitoring of antibiotic residues in Nile tilapia (Oreochromis niloticus) and the emergence of bacteria resistant to antibiotics. This study was carried out order to fully understand the mechanisms by which bacteria become resistant to a wide range of antibiotics and to fully understand the patterns of bacteria susceptibility and resistance to antibiotics. However, antibiotic susceptibility testing is a standard procedure to help with antibiotic selection to prevent indiscriminate prescribing, inappropriate dosing and duration of treatment, and over-the-counter antibiotic availability in aquaculture.
Similarity in antibiotic classes used to treat bacterial infections becomes crucial which necessitates the need to investigate the \occurrence of a group of clinically significant bacteria and clarify their antibiotic resistance patterns. The goal of the antimicrobial susceptibility test is to identify the sensitivity or resistance profile of pathogenic bacteria to different antimicrobial compounds in Nile tilapia in order to make recommendations on environmentally friendly methods like phage therapy.
