Prevalence, molecular Cاharacterization, virulotyping, and antibiotic resistance of motile aeromonads isolated from Nile tilapia farms at northern Egypt

Abstract

This study was aimed to survey Aeromonas spp associated with cultured Nile tilapia Oreochromis niloticus (O. niloticus) showing signs of motile Aeromonas septicemia (MAS) at different fish farms; molecular characterization and identification of test isolates; and to test the isolates for their antimicrobial and virulence activities that contribute to its pathogenesis. Design: Observational study. Animals: 280 Nile tilapia. Procedures: Clinically diseased 280 Nile tilapia, were collected from different localities at Kafr El-Sheik and Dakahlia governorates. The clinical picture and gross lesions were recorded. Aeromonas spp were isolated and presumptively identified using API20E. The identification was confirmed using PCR. Hemolysin (hylA), lipase, and aerolysin (aerA) virulence genes were detected among isolates obtained from different sampling sites. Besides, antimicrobial activity was reported for the identified A. hydrophila. Results: General septicemic signs were evident on Nile tilapia including, skin hemorrhages and ulcerations, bilateral exophthalmia, congested internal organs with significant mortalities. The prevalence of bacterial infection among naturally diseased Nile tilapia was 79.17, 70, and 58.33 in Kafr El-Sheikh, El-Manzala, and Gamsa fish farms, respectively. The most prevalent bacterial isolates were aeromonads (29.84 %), of all, 65.63 A. hydrophila, 18.75 A. caviae, and 15.63 A. sobria. All isolates were positively amplified using a species-specifying primer to determine A. hydrophila. Virulence genes detection revealed that five A. hydrophila isolates (83.3 %) harbored the aerA gene. Meanwhile, hylA and lipase genes positive isolates were lower reaching 16.7 % for both genes. A. hydrophila was highly sensitive to ciprofloxacin, amikacin, trimethoprim, and chloramphenicol, and MAR index of A. hydrophila isolates was ranged from 0.16-0.42 Conclusion and clinical relevance: Our findings demonstrate that Aeromonas spp are among the bacterial pathogens implicated in summer mortalities in tilapia fish farms in Egypt. Besides, determination of the prevalence, virulence genes, and antibiotic resistance pattern associated with the disease outbreaks is critical data that warrant the development of strategies to proper monitoring and farm management practices.

Prevalence, genetic diversity, and antimicrobial susceptibility of Vibrio spp. infected gilthead sea breams from coastal farms at Damietta, Egypt

“…In contrast, when the value is greater than 0.2, a high rate of antibiotic use in the treatment strategies is expected. In our study, the MAR index value was greater than 0.2, which indicates high-risk contaminated bacterial sources with high rates of antibiotic use [ 74 , 75 ]. Most aquatic bacteria are subjected to many marine pollutants, such as agricultural runoff, sewage, and medical waste, which carry variable amounts of antimicrobials that trigger antimicrobial resistance in aquatic bacteria [ 76 ].…”

Effect of Different Substrates and Nutrient Solutions on Growth and Productivity of Soilless Cultured Head Lettuce with using Solar Energy for Operating Fertigation System

“…Renewable energy sources (such as wind, hydraulic, geothermal, tidal, biomass and solar) are considered an urgent technological option for generating sustainable, clean, cheap and safe energy, especially in light of global climate changes resulting from the excessive use of non-renewable energy sources such as fossil fuels. One of the most promising renewable energy sources in these connections is solar energy, which converted to electricity by photovoltaic (PV) panels (Salem, 2016 andOgbomo et al, 2017). Due to Egypt's proximity to the equator, it enjoys a large number of sunshine hours daily, especially during the summer season.…”

Antibiotic Susceptibility Profile and Nutritional Evaluation of Raw and Cooked Meat of Cyprinus Carpio

“…According to regulatory bodies, eating fish is recommended 1-2 days per week, with one part of oily fish containing 200-500mg of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (Sobczak et al, 2020). In the fish culture, health problems generally occur due to the interaction of host, pathogen, and environment (Salem et al, 2020). A commodity can be divided into three categories: indigenous bacteria, nonindigenous bacteria (enteric bacteria), and contamination of fish by bacteria during storage, manufacturing or food preparation (Lerma-Fierro et al, 2020).…”