الفهرس 
Introduction
Taxonomy and classificationOnly 14 pages are availabe for public view
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Abstract
One hundred and forty random samples of milk and some dairy desserts including market milk, small scale ice-cream, rice pudding (rice with milk) and muhellbei (35 samples, each) were collected from different dairy shops and supermarkets in Assiut city, Egypt for enumeration, isolation and identification of pathogenic Aeromonas species and for detection for their pathogenicity.
Aeromonas species could be detected using surface plating technique on m-Aeromonas selective agar plates, in 19 (54.29%), 12 (34.29%) of the examined market milk and small scale ice-cream with an average counts of 4.3×104 cfu/ml and 5.0×102 cfu/g, respectively. None of the 70 examined rice pudding (rice with milk) and muhallebi samples yielded Aeromonas species since post-processing contamination of these products is more easy to be prevented under close control during packing.
Aeromonas species recovered on m-Aeromonas selective agar plates could be differentiated into A.hydrophila which could detected in 5 (14.29%) and 3 (8.57%), A.caviae could be detected in 8 (22.86%) and 5 (14.29%), A. sobria could be detected in 4 (11.43%) and 3 (8.57%), While A.trota could be detected in 2 (5.71%) and 1 (2.86%) of the examined market milk and small scale ice-cream samples, respectively.
The isolated Aeromonas species in this study were tested for its virulence properties by haemolytic , proteolytic and lipolytic assay and 2 strains (2 of 8) of A.hydrophila exhibited both haemolytic and proteolytic activities, while 3 strains (3 of 8) and 3 strains (3 of 8) exhibited proteolytic and lipolytic activities, respectively.
One strain from A. caviae 1 (1 of 13) produced both proteolytic and lipolytic activities, one strain 1 (1 of 13), 6 (6 of 13) and 3 (3 of 13) produced haemolytic, proteolytic and lipolytic activities, respectively.
One strain (1 of 7) from A. sobria exhibited both haemolytic and proteolytic activities, 2 (2 of 7), 3 (3 of 7) produced proteolytic and lipolytic activities, respectively. A.trota, one strain produced both proteolytic and lipolytic activities and one strain exhibited proteolytic activity.
In this work, PCR protocol used for amplification and detection of lipase (lip) gene of A. hydrophila isolates to confirm their pathogenicity as the presence of lipase gene is an index of virulence possessions. Eight isolates were subjected to PCR for detection of lip gene and all (100%) were positive for lip gene.
The public health importance of Aeromonas species as well as the recommended sanitary measures were discussed.