ABSTRACT
Aeromonas are Gram-negative bacteria that are ubiquitous in the microbial biosphere and are found in almost every environmental niche, including aquatic habitats, soil, foods, vegetables, domesticated pets and birds. The aquatic environment is the natural habitat of Aeromonads and they can be isolated from chlorinated and non- chlorinated water such as rivers, lakes, ponds, groundwater and surface water. They are well known as causative agents of intraintestinal and extraintestinal diseases in humans and other disease in both warm and cold-blooded animals in terrestrial and aquatic habitats.The aim of this study was to isolate and characterize Aeromonas species from frozen chicken and turkey meat sold in some markets in Benin City Edo State, Nigeria.
Samples of frozen chicken and turkey were collected and transported in cold chain to the laboratory for analysis. The microbial count of the chicken and turkey samples were determined using standard microbiological techniques. The Aeromonas species isolated were characterized on the basis of their morphological, biochemical, haemolysin production as well as antibiotic susceptibility test using standard microbiological techniqus. Molecular characterization of the isolates was carried out using polymerase chain reaction (PCR). The amplified DNA was Agarose gel electrophoresis which gives discrete bands and the edited sequences were used for similar searches using Basic Local Alignment Search Tool (BLAST).
The total Aeromonas count for the chicken samples were in the ranged of 0.42±0.7 x103 cfu/g to 0.78±0.15 x103 cfu/g and that of turkey samples were 0.07±0.05 x103 cfu/g to 0.59±0.14 x103 cfu/g. The total bacterial count of the chicken samples ranged from 0.40±0.13 x103 cfu/g to 1.34±0.21 x103 cfu/g while the turkey samples ranged from 0.27±0.08 x103 cfu/g to 0.91±0.12 x103 cfu/g. A total of four (4) Aeromonas hydrophila strains were recovered from chicken and turkey samples analyzed, they include: Aeromonas hydrophila MK463970 strain ocho1; Aeromonas hydrophila MK463971 strain ocho2; Aeromonas hydrophila MK463972 strain ocho3 and Aeromonas hydrophila MK463973 strain ocho4. The bacteria isolated from the samples also includes: Escherichia coli, Staphylococcus aureus and Pseudomonas species. The susceptibility of the Aeromonas isolates to the antibiotics tested shows that all the Aeromonas hydrophila strains weresusceptible to Ciprofloxacin. Streptomycin, Chloramphenicol and Augmentin showed intermediate zones of inhibition to all the strains tested; Pefloxacin and sparfloxacin produced only an insignificant zones of activity; Septrin and Tarivid produced no clear zone. All the strains of Aeromonas hydrophila isolated produced only beta haemolysis (β- haemolysis).The presence of Aeromonas hydrophilain chicken and turkey meat samples as pathogens is of public health importance as they are known to cause both gastrointestinal and extraintestinal infectious diseases when ingested through contaminated sources. Therefore, it is necessary to pay attention to Aeromonas as disease causing organisms in the field of Food and Environmental Microbiology for their ability to survive and produce toxins in both psychrophilic and mesophilic environments.
