Global Advanced Research Journal of Microbiology (GARJM) ISSN: 2315-5116
November 2017 Vol. 6(7): pp. 062-069
Copyright © 2017 Global Advanced Research Journals
Full Length Research Paper
Phenotypic and Genotypic Detection of Enterotoxigenic Staphylococcus aureus in Domestic Dairy Products in Port Said Governorate, Egypt.
Saly M.E. Toubar1, Abdllah. A. Elbialy2 and Mahmoud. M.M. Zaky3.
1,3-Botany department, Faculty of science, Port-Said University, Egypt.
2-Microbiology and immunology department, Faculty of medicin, Zagazig University, Egypt.
Accepted 20 November, 2017
Staphylococcus aureus is an important food- borne pathogen involved in a variety of invasive diseases. So the current study aimed to detect the frequency of contaminated dairy products by S. aureus and the presence of enterotoxins genes in the isolated S. aureus strains. One hundred samples of milk and milk products were collected randomly of different areas in Prot Said governorate. Thirty milk samples; twenty raw milk, six pasteurized. milk and four powdered milk. Thirty cheese samples; ten karish cheese, five damitta cheese, five rommy cheese, five cheedar cheese and five cooked cheese. Twenty Yoghurt samples; ten canned yoghurt pasteurized and ten hand-made yoghurt non-pasteurized. Staphylococcus aureus strains were isolated by cultivation on two selective media, Baird-Parker agar and Mannitol Salt agar . This study deteted no S. aureus growth at pasteurized milk , the organism in pasteurized milk by a percentage of (70%) and attributed that to inefficacy of the thermal process. The current study detected S. aureus in 50 % of the examined samples of cheese. S. aureus only in 10 % of the cheese samples Karish cheese was the highest in S. aureus contamination (70%) among different types included in the present study. Rommy and damitta cheese also show a high rate o contamination (60%). The least percentage was in cheedar and cooked cheese (20%) each. This may be due to unhygienic storage and handling of rommy and damaitta cheese while cooked and cheedar cheese were sold sealed. Yoghurt is the most popular type of fermented milk in Egypt, the present study detected S. aureus in 35% of all examined samples. Similar, S. aureus detected in 72% of yoghurt samples collected from different dairy shops and supermarkets, in Prot Said governorate. The present study detected S.aureus in 40% of the examined samples of both cream and butter, which came after milk (53.5%) and cheese (50%). Percentage of positive samples for S. aureus were higher in milk (53.3 %), followed by cheese (50 %), cream and butter (40 %) and lately yoghurt (35 %).Staphylococcal Enterotoxins are classified by serological criteria into types designated SEA to SEE and SEG to SEU and encoded by sea to see and seg to seu genes. One of the goals of this study is to determine the presence of enterotoxin genes among isolated strain of S. aureus from dairy Products. To achieve this goal, Multiplex PCR technique was applied on -S. aureus colonies from each positive sample isolated from culture on Baird- Parker agar. In the present study enterotoxin genes were detected in 19 isolated strains of S. aureus out of 46 strains positive for S. aureus in a percent of (41.3 %). This result is higher than that detected by enterotoxin gene in (31.1 %) in isolated S. .aureus colonies from milk and milk products. On the other hand SE detected gene in 37 % of raw milk samples, SEB is also incriminated in food poisoning. Staphylococcal enterotoxin (A) gene was highly reported (52,6%), while enterotoxin (B) gene was reported in (31.6%). Double enterotoxin genes (sea and seb) were reported in (15.8%). Regarding genotypic findings by PCR, sea gene was isolated with a higher frequency than seb gene as it was detected in 52.6% of all isolated enterotoxin genes, followed by seb (31.6%) and lastly (sea+seb) (15.8%). agarose gel electrophoresis for PCR showing of 270. bp sea gene and 165 bp seb gene. (Lane M) is the ( 100 bp ladder marker), (Lane 2) is for sea, (Lane 3) is for seb, (Lane 4) is for both genes (sea& seb).
Keywords: Staphylococcus aureus, Phenotypic and Genotypic, Domestic Dairy.
- Saly M.E. Toubar on Google Scholar
- Saly M.E. Toubar on Pubmed
- Abdllah. A. Elbialy on Google Scholar
- Abdllah. A. Elbialy on Pubmed
- Mahmoud. M.M. Zaky on Google Scholar
- Mahmoud. M.M. Zaky on Pubmed