scholarly journals Molecular Detection of Staphylococcal Enterotoxins and mecA Genes Products in Selected Food Samples Collected from Different Areas in Khartoum State

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mohammed Yahya Ahmed ◽  
Hashim Abdalbagi Ali ◽  
Babbiker Mohammed Taher Gorish ◽  
Sara Omer Ali ◽  
Eman Saif Aldein Abdalrhim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Meca Gene ◽  
Food Poisoning ◽  
Meat Products ◽  
Low Frequency ◽  
Raw Milk ◽  
Food Samples ◽  
Increased Risk ◽  
Enterotoxin B ◽  
Staphylococcus Aureus Enterotoxins

Staphylococcal food poisoning is an intoxication that results from the consumption of improperly prepared or stored foods containing sufficient amounts of one or more preformed S. aureus enterotoxins. Nowadays, many researchers worldwide noted an emergence of resistant strains such as Staphylococci particularly for the antibiotic methicillin. Therefore, this study was aimed to determine the existence of Staphylococcus aureus and its enterotoxins, mecA genes, in selected food samples. A total of 400 selected food samples were collected from different areas in Khartoum State. The selected foods included cheese, meat products, fish, and raw milk. One hundred samples from each type of food were cultivated, and the resultant growth yielded 137 (34.25%) S. aureus, 126 (31.5%) bacteria other than S. aureus, and 137 (34.25%) yielded no growth. Eighty-four of the 137 S. aureus isolates were randomly selected and tested for the presence of mecA and enterotoxin genes. The oxacillin sensitivity test showed that 15 (11%) of 137 S. aureus isolates were oxacillin resistant. The PCR assay showed that the mecA gene was detected in 15 of 84 (17%) S. aureus isolates. Simultaneously, only 2 (2.385%) out of 84 S. aureus isolates showed an enterotoxin B gene product. There was a relatively moderate prevalence of methicillin-resistant Staphylococcus aureus with very low frequency of enterotoxin B gene in different kinds of selected food samples collected from Khartoum State. These findings elucidate the increased risk on public in Khartoum being affected by Staphylococcal food poisoning upon consumption of dairy or meat products prepared in unhygienic conditions that could lead to intoxication by Staphylococcus aureus enterotoxins.

scholarly journals Molecular detection of Staphylococcal enterotoxins and mecA genes products in food samples collected from different areas in Khartoum state

2020 ◽  
Author(s):  
Mohammed Yahya ◽  
Hashim Abdalbagi Ali ◽  
Babbiker Mohammed Taher Gorish ◽  
Sara Omer Ali ◽  
Eman Saif Aldein Abdalrhim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Meca Gene ◽  
Food Poisoning ◽  
Meat Products ◽  
Low Frequency ◽  
Raw Milk ◽  
Food Samples ◽  
Enterotoxin Genes ◽  
Resistant Strains ◽  
Enterotoxin B

Abstract Background Staphylococcal Food Poisoning is an intoxication that results from the consumption of improperly prepared or stored foods containing sufficient amounts of one or more preformed S. aureus enterotoxins. Now days many researchers worldwide noted an emerging of resistant strains Staphylococci especially for the antibiotic Methicillin. Therefore, this study was aimed to determine the existence of Staphylococcus aureus and its enterotoxins, mecA genes in food samples. Results A total of 400 samples were collected from different areas in Khartoum state. The type of foods included Cheese, Meat products, Fish and Raw milk, 100 samples for each. out of 400 samples cultivated 137 (34.25%) isolates were identified as S. aureus, 126 (31.5%) were identified as bacteria other than S. aureus and 137 (34.25%) were yield no growth. Of 137 S.aureus isolates, 84 were randomly selected and examined for the presence mecA and enterotoxin genes products. Oxacillin sensitivity test showed that 15(11%) of 137 S.aureus isolates were Oxacillin resistant. The PCR assay showed that mecA gene was detected in 15 of 84 (17%) S. aureus isolates. While only 2 (2.385%) out of 84 S. aureus isolates were show an enterotoxin B gene product. Conclusion There was a relatively moderate prevalence of Methicillin resistant staphylococcus aureus with very low frequency of enterotoxin B gene in different kinds of food samples which collected from Khartoum state. These findings highlight the high potential risk for consumers of meat and dairy products especially in the absence of strict hygienic and preventive measures to avoid Staphylococcus aureus enterotoxins production in foods.

scholarly journals Molecular detection of Staphylococcal enterotoxins and mecA genes products in food samples collected from different areas in Khartoum state.

2020 ◽  
Author(s):  
Mohammed Yahya ◽  
Hashim Abdalbagi Ali ◽  
Babbiker Mohammed Taher Gorish ◽  
Sara Omer Ali ◽  
Eman Saif Aldein Abdalrhim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Meca Gene ◽  
Food Poisoning ◽  
Meat Products ◽  
Low Frequency ◽  
Raw Milk ◽  
Food Samples ◽  
Enterotoxin Genes ◽  
Resistant Strains ◽  
Enterotoxin B

Abstract Background: Staphylococcal Food Poisoning is an intoxication that results from the consumption of improperly prepared or stored foods containing sufficient amounts of one or more preformed S. aureus enterotoxins. Now days many researchers worldwide noted an emerging of resistant strains Staphylococci especially for the antibiotic Methicillin. Therefore, this study was aimed to determine the existence of Staphylococcus aureus and its enterotoxins, mecA genes in food samples.Results: A total of 400 samples were collected from different areas in Khartoum state. The type of foods included Cheese, Meat products, Fish and Raw milk, 100 samples for each. out of 400 samples cultivated 137 (34.25 %) isolates were identified as S. aureus, 126 (31.5%) were identified as bacteria other than S. aureus and 137 (34.25%) were yield no growth. Of 137 S. aureus isolates, 84 were randomly selected and examined for the presence mecA and enterotoxin genes products. Oxacillin sensitivity test showed that 15(11%) of 137 S.aureus isolates were Oxacillin resistant. The PCR assay showed that mecA gene was detected in 15 of 84 (17%) S. aureus isolates. While only 2 (2.385%) out of 84 S. aureus isolates were show an enterotoxin B gene product. Conclusion: There was a relatively moderate prevalence of Methicillin resistant staphylococcus aureus with very low frequency of enterotoxin B gene in different kinds of food samples which collected from Khartoum state. These findings highlight the high potential risk for consumers of meat and dairy products especially in the absence of strict hygienic and preventive measures to avoid Staphylococcus aureus enterotoxins production in foods.

scholarly journals Molecular detection of Staphylococcal enterotoxins and mecA genes products in selected food samples collected from different areas in Khartoum state.

2020 ◽  
Author(s):  
Mohammed Yahya ◽  
Hashim Abdalbagi Ali ◽  
Babbiker Mohammed Taher Gorish ◽  
Sara Omer Ali ◽  
Eman Saif Aldein Abdalrhim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Food Poisoning ◽  
Meat Products ◽  
Low Frequency ◽  
Raw Milk ◽  
Food Samples ◽  
Enterotoxin Genes ◽  
Increased Risk ◽  
Resistant Strains ◽  
Enterotoxin B

Abstract Background: Staphylococcal food poisoning is an intoxication that results from the consumption of improperly prepared or stored foods containing sufficient amounts of one or more preformed S. aureus enterotoxins. Nowadays many researchers worldwide noted an emergence of resistant strains Staphylococci particularly for the antibiotic methicillin. Therefore, this study was aimed to determine the existence of Staphylococcus aureus and its enterotoxins, mecA genes in selected food samples.Results: A total of 400 selected food samples were collected from different areas in Khartoum state. The selected foods included cheese, meat products, fish and raw milk. One hundred sample from each type of food were cultivated and the resultant growth yielded 137 (34.25 %) S. aureus, 126 (31.5%) bacteria other than S. aureus and 137 (34.25%) yielded no growth. Eighty-four of the137 S. aureus isolates were randomly selected and tested for the presence of mecA and enterotoxin genes. Oxacillin sensitivity test showed that 15(11%) of 137 S. aureus isolates were Oxacillin resistant. The PCR assay showed that the mecA gene was detected in 15 of 84 (17%) S. aureus isolates. Simultaneously, only 2 (2.385%) out of 84 S. aureus isolates showed an enterotoxin B gene product. Conclusion: There was a relatively moderate prevalence of methicillin-resistant staphylococcus aureus with very low frequency of enterotoxin B gene in different kinds of selected food samples that collected from Khartoum state. These findings elucidate the increased risk on public in Khartoum being affected by Staphylococcal food poisoning upon consumption of dairy or meat products prepared in unhygienic conditions that could lead to intoxication by Staphylococcus aureus enterotoxins.

Phylogeny Characterization of Seb Gene Encoding Enterotoxins in Staphylococcus aureus Isolated from Raw Milk and Cheese

2019 ◽  
Vol 9 (o3) ◽  
Author(s):  
Fatima N. Aziz ◽  
Laith Abdul Hassan Mohammed-Jawad
Keyword(s):  
Staphylococcus Aureus ◽  
Food Poisoning ◽  
Raw Milk ◽  
Staphylococcal Enterotoxin B ◽  
Human Pathogen ◽  
Conventional Pcr ◽  
Biochemical Tests ◽  
Specific Primers ◽  
Gene Encoding

Food poisoning due to the bacteria is a big global problem in economically and human's health. This problem refers to an illness which is due to infection or the toxin exists in nature and the food that use. Milk is considered a nutritious food because it contains proteins and vitamins. The aim of this study is to detect and phylogeny characterization of staphylococcal enterotoxin B gene (Seb). A total of 200 milk and cheese samples were screened. One hundred ten isolates of Staphylococcus aureus pre-confirmed using selective and differential media with biochemical tests. Genomic DNA was extracted from the isolates and the SEB gene detects using conventional PCR with specific primers. Three staphylococcus aureus isolates were found to be positive for Seb gene using PCR and confirmed by sequencing. Sequence homology showed variety range of identity starting from (100% to 38%). Phylogenetic tree analyses show that samples (6 and 5) are correlated with S. epidermidis. This study discovered that isolates (A6-RLQ and A5-RLQ) are significantly clustered in a group with non- human pathogen Staphylococcus agnetis.

Presence of Immune Evasion Cluster and Molecular Typing of Methicillin-Susceptible Staphylococcus aureus Isolated from Food Handlers

2016 ◽  
Vol 79 (4) ◽  
pp. 682-686 ◽  
Author(s):  
LÍVIA G. BAPTISTÃO ◽  
NATHALIA C. C. SILVA ◽  
ERIKA C. R. BONSAGLIA ◽  
BRUNA F. ROSSI ◽  
IVANA G. CASTILHO ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Evasion ◽  
Close Contact ◽  
Meca Gene ◽  
Low Frequency ◽  
Food Handlers ◽  
Spa Typing ◽  
Typing Method ◽  
Spa Types ◽  
Immune Evasion Cluster

ABSTRACT The hands and noses of food handlers colonized by Staphylococcus aureus are an important source of food contamination in restaurants and food processing. Several virulence factors can be carried by mobile elements in strains of S. aureus, including the immune evasion cluster (IEC). This gene cluster improves the capacity of S. aureus to evade the human immune response. Many studies have reported the transmission of strains between animals and humans, such as farm workers that have close contact with livestock. However, there are few studies on the transmission between food and food handlers. The aim of this study was to detect the IEC and the mecA gene in strains isolated from food handlers and to type these strains using the spa typing method. Thirty-five strains of S. aureus isolated from the noses and hands of food handlers in three different kitchens were analyzed for the presence of the mecA gene and IEC and by spa typing. All strains were negative for the mecA gene, and the presence of IEC was observed in 10 (28.6%) strains. Fifteen different spa types were observed, with the most frequent being t127 (42.85%) and t002 (11.42%). Strains from the two most prevalent spa types and a novel spa type were typed by multilocus sequence typing. spa types t127, t002, and t13335 were determined to be multilocus sequence types (ST) ST-30, ST-5, and ST-45, respectively. The food handlers may have been contaminated by these strains of S. aureus through food, which is suggested by the low frequency of IEC and by ST that are observed more commonly in animals.

STAPHYLOCOCCUS AUREUS AND STAPHYLOCOCCAL FOOD INTOXICATIONS. A REVIEW

1972 ◽  
Vol 35 (1) ◽  
pp. 21-29 ◽  
Author(s):  
T. E. Minor ◽  
E. H. Marth
Keyword(s):  
Staphylococcus Aureus ◽  
Secondary Metabolite ◽  
Soluble Protein ◽  
Food Poisoning ◽  
Water Soluble ◽  
Primary Metabolite ◽  
Water Soluble Protein ◽  
Assay Methods ◽  
Enterotoxin B ◽  
General Aspects

Staphylococcal food poisoning is strictly an intoxication which is caused by a water-soluble protein called enterotoxin that is secreted by staphylococcal cells, i.e. an exotoxin. After a general discussion of the properties of the enterotoxins, methods and media employed for producing high toxin yields are detailed. Mechanisms whereby these toxins are secreted differ in that enterotoxin A behaves as a primary metabolite and enterotoxin B acts as a secondary metabolite. Several studies on and explanations of the synthesis of enterotoxins are presented. Assay methods for these toxins that are discussed include bioassay techniques and serological procedures. Finally, some general aspects of the epidemiology of staphylococcal intoxications are described.

scholarly journals Growth characterisation of Staphylococcus aureus in milk: a quantitative approach

2009 ◽  
Vol 27 (No. 6) ◽  
pp. 433-453 ◽  
Author(s):  
A. Medveďová ◽  
Ľ. Valík ◽  
Z. Sirotná ◽  
D. Liptáková
Keyword(s):  
Staphylococcus Aureus ◽  
Growth Rate ◽  
Incubation Temperature ◽  
Food Poisoning ◽  
Raw Milk ◽  
Lag Phase ◽  
Phase Duration ◽  
Temperature Range ◽  
Root Model ◽  
Toxigenic Strains

<i>Staphylococcus aureus</i> is a pathogenic bacterium that induces several of human illnesses. The staphylococcal enterotoxin (SE) production as the results of previous growth of toxigenic strains is the most crucial problem which may lead to the staphylococcal food poisoning outbreaks in humans. That is why the growth of three strains of <i>Staphylococcus aureus</i> was characterised in milk and modelled in dependence of temperature. For the lag phase duration of <i>S. aureus</i> 2064, the Davey model was used with the following result: ln(1/lag) = 1.973 – 87.92/<i>T</i> + 285.09/<i>T</i><sup>2</sup> (<i>R</i><sup>2</sup> = 0.962). The dependence of the growth rate on incubation temperature was modelled by the Ratkowsky square root model and Gibson in sub-optimal and whole temperature range, respectively. The validation of both models showed high significance of the growth rate data fitting. The optimal temperature of <i>T</i><sub>opt</sub> = 38.5°C was resulted from Gibson model for the <i>S. aureus</i> 2064 growth in milk. For practical purpose, the time necessary for the increase of <i>S. aureus</i> by 3 log counts was also calculated within the growth temperature range. These data may provide useful information e.g. for the producers using raw milk in their artisanal cheese practice as the specific strains were used in this study.

scholarly journals TSST-1, enterotoxin and bacteriocin-like substance production by Staphylococcus aureus isolated from foods

2013 ◽  
Vol 65 (5) ◽  
pp. 1537-1544 ◽  
Author(s):  
S.A. Carvalho ◽  
L.S. Carmo ◽  
E.F. Abreu ◽  
R.S. Dias ◽  
A.C.M. Apolônio ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bovine Milk ◽  
Food Poisoning ◽  
Brain Heart Infusion ◽  
Food Samples ◽  
Antagonistic Activity ◽  
Toxic Shock ◽  
Toxic Shock Syndrome Toxin ◽  
Reference Strains ◽  
Infusion Agar

The production of Toxic Shock Syndrome Toxin-1 (TSST-1), enterotoxins and bacteriocin-like substances was evaluated in 95 strains of Staphylococcus aureus recovered from raw bovine milk (n=31) and from food samples involved in staphylococcal food poisoning (n=64). Enterotoxigenicity tests with the membrane over agar associated to optimal sensibility plate assays were performed and showed that 96.77% of strains recovered from milk and 95.31% from food samples produced enterotoxins A, B, C, D or TSST-1. Reference strains S. epidermidis, Bacillus cereus, Listeria monocytogenes, Lactobacillus casei, Pseudomonas aeruginosa, S. aureus, Salmonella Typhimurium, Escherichia coli, Enterococcus faecalis and Bacteroides fragilis were used as indicator bacteria in the antagonistic assays, the first five being sensitive to antagonistic substances. Brain heart infusion agar, in pH values ranging from 5.0 to 7.0 in aerobic atmosphere showed to be the optimum condition for antagonistic activity as evaluated with the best producer strains against the most sensitive indicator bacterium, L. monocytogenes. Sensitivity to enzymes confirmed the proteinaceous nature of these substances. Neither bacteriophage activity nor fatty acids were detected and the antagonistic activity was not due to residual chloroform. Results did not establish a positive correlation between the bacteriocinogenic profile and toxigenicity in the tested S. aureus strains.

An Immunomagnetic PCR Signal Amplification Assay for Sensitive Detection of Staphylococcus aureus Enterotoxins in Foods

2009 ◽  
Vol 72 (12) ◽  
pp. 2538-2546 ◽  
Author(s):  
LEENALITHA PANNEERSEELAN ◽  
PETER M. MURIANA
Keyword(s):  
Staphylococcus Aureus ◽  
Signal Amplification ◽  
Magnetic Beads ◽  
Food Poisoning ◽  
High Sensitivity ◽  
The United States ◽  
Food Samples ◽  
Dna Oligonucleotides ◽  
Amplification Assay ◽  
Covalently Linked

Enterotoxigenic strains of Staphylococcus aureus produce a variety of heat-stable staphylococcal enterotoxins (SEs) that are a prevalent cause of food poisoning in the United States and other countries. Many immunological and biochemical assays often work well in buffer systems but are hindered when tested in the complex chemical environment of foods. To overcome these biases and improve the limits of detection, we implemented an immunomagnetic PCR signal amplification assay (iPCR-SA) for recovery and detection of SEA and SEB in foods. Anti-SEA or anti-SEB primary antibodies were coated onto COOH-modified magnetic beads using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide reagent. Secondary antibodies were covalently linked to amino-modified reporter DNA oligonucleotides (563 bp) via the linker molecule succinimidyl-4[N-maleimidomethyl]-cyclohexane-1-carboxylate. An internal 159-bp portion of the reporter DNA retained by the captured toxin molecule was then amplified by real-time PCR. A semiautomated Bead Retriever proved extremely helpful in both the application of the conjugation chemistries and required washes and the recovery and washing of bead-conjugated toxin from tested food samples. The procedure was simple, and analyses were completed in 5 to 6 h. The assay was sufficiently robust that we were able to detect SEA and SEB in tryptic soy broth, milk, lemon cream pie, tuna salad, deli turkey, and ground turkey at levels as low as 7.5 fg/ml. SE was still detected at high sensitivity after heating in food samples for typical pasteurization or cooking regimens. Sensitivity was diminished only when samples were subjected to extreme heating.

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