These products should be handled with care since fish may be infected by A. hydrophila strains that cause skin infections .Studies on frozen and fresh fish on Aeromonas strains related to the deterioration process of fresh and frozen fish, in frozen foods could be recovered .A survey conducted in the state of Sao Paulo evaluated salmon microbiology by quantifying microorganisms in the flesh of 31 salmon samples and detected Aeromonas ssp. and other microorganisms in the retail network of several cities in the state of Sao Paulo, Brazil. Aeromonas ssp. Have been detected in 41.95% of the samples, with population variation from 2.0 × 102to 8.0 × 103 CFU/G . Another study in the state of Rio Grande do Sul, Brazil,investigated the occurrence of Aeromonas hydrophila and Campylobacter jejuniin the samples of fresh tuna captured on the coast of Santa Catarina and evaluated 85 samples of tuna fillets by using bacteriological analysis andPCR. Eleven samples were positive for Aeromonas spp., with 10/11 proved to be Aeromonas hydrophila by PCR The sawfish was contaminated by A. hydrophila , vectoring the pathogenic agent when the fish was consumed .
The above-mentioned study collected 60 samples of live and frozen fish from 15 local markets in Baghdad, Iraq, to isolate Aeromonas hydrophila and determine hemolytic activity, isolates’ cytotoxicity, and their susceptibility to antibiotics. Furthermore, 65% of the samples had Aeromonas hydrophila, 76.6% were found in samples of live fish and 53.3% in frozen fish; hemolysisα e β was detected in 94.87% of the samples; 100% of the isolates from live fish had β hemolysis, whereas 85.7% showed β hemolysis, and 14.3% showedα hemolysis; 97.43% of the isolates had cytotoxic effect on Vero cells. All isolates were 100% resistant to penicillin, ampicillin, cloxacillin, and bacitracin, according to the sensitivity test, whereas resistance to other antibiotics was 56.5% to oxitetraciclina; 33.4% to tetracycline, 30.8% to cefoxetin, hydroponic bucket and 28.2% to chloramphenicol and kanamycin. Isolates were resistant to streptomycin and rifampicin,respectively, at 23.1% and 15.4%. Four species of Aeromonas spp. were identified in all samples analyzed in sports fish farms in the state of Maranhao, Brazil. These fish farms were a possible risk in the transmission of pathogenic Aeromonas and a risk factor for consumers offish bred on these farms .
Aeromonas are gastroenteritis-causing bacteria that are transmitted to humans by contact with the etiological agent and the intake of contaminated meat, vegetables, and water. Several studies suggested that infection by Aeromonas was one of the causes of traveler’s diarrhea .A. hydrophila , free-living bacteria, were found to cause diseases in fish; they are an opportunistic pathogen in humans. A. hydrophila infections in animals and humans in Thailand first occurred in 1976 and 1979, respectively, with fish mortality between 0% and 20%. Diarrhea is prevalent in the cases of human infection. Vila et al. showed that A. veronii biovar sobria and A. caviae are mostly associated with traveler’s diarrhea. Pereira et al. investigated the presence of Aeromonas in neonates hospitalized in Rio de Janeiro, Brazil and obtained 94.6% prevalence rate for Aeromonas . A. caviae was the most prevalent in the samples. They may also cause skin damage to infected individuals. Bacteria cause intestinal infections associated with severe diarrhea and may be lethal if it infects other regions of the body, such as an open wound. The presence of Aeromonas spp. in foods of animal origin suggests that these species persists even when hygiene and sanitary control is employed, leading to a risk to consumers’ health Aeromonas spp. are important pathogenic microorganisms.
Since they originate from water and other environments, they can adapt themselves to a wide variety of environments owing to several virulence factors. The above is directly linked to the microorganism’s pathogenicity for human beings In fact,water and food play an important role in the transmission of the pathogen .Because of the remarkable diversity of ecosystems in which Aeromonas inhabit,they have become resistant to antimicrobial agents and become highly virulent.In fact, several Aeromonas species secrete extracellular proteins such as amylase, chitinase, elastase, aerolysine, nuclease, gelatinase, lecitinase, lipase, and protease, which, according to the literature, are known to be virulent factors that cause disease in fish and human beings A. hydrophila is a gram-negative bacterium with virulence factors such as hemolysins,aerolysins, adesins, and enterotoxins.