scholarly journals Development and evaluation of a novel combinatorial selective enrichment and multiplex PCR technique for molecular detection of major virulence-associated genes of enterotoxigenic Staphylococcus aureus in food samples

2013 ◽  
Vol 116 (2) ◽  
pp. 435-446 ◽  
Author(s):  
S. Nagaraj ◽  
S. Ramlal ◽  
M.H. Sripathy ◽  
H.V. Batra
2021 ◽  
pp. 61-74
Author(s):  
Sundus A. Jassim ◽  
Nuha J. Kandala

Foodborne diseases are a major risk for human health. Millions of people become sick as a result of eating contaminated food with microorganisms that cause diseases. S.  aureus is considered as one of the most important pathogenic bacteria, having the ability to  activate certain genes that encode for heat stable enterotoxins and cause Staphylococcal food poisoning. Thus, this study aimed to determine the prevalence of multi resistant Staphylococcus aureus that produce enterotoxins in different sources of food . Forty nine isolates were identified as S.aureus, according to morphological and biochemical tests. They were isolated from 387 different food samples from several randomly covered restaurants and supermarkets in different regions of Baghdad. Molecular diagnosis of S. aureus using specific primers for the 16S rRNA gene was carried out by Polymerase Chain Reaction (PCR ) technique . Susceptibility of 43 isolates of S.aureus was tested against 15 antimicrobial agents. The results revealed that all the isolates were resistant (100%) to mecillinam, highly resistant to vancomycine and meropenemin  (74.4 %) and  moderately resistant to Oxacillin, Erythromycin Cefotaxime, and Cefiximein (67.4, 60.4, 62.8, , 60.5 %, respectively), while they showed low resistance to Gentamicin (34.8%). In addition, all of these isolates were susceptible  to Tigecycline and Amoxicillin/ clavulanic acid and Cefoxitin-Cloxacilin. High percentages of oxicillin resistant S. aureus were isolated from cooked food samples, followed by meat products, and with less percentage from pastry products. Molecular detection of enterotoxins A and B of Staphylococcus aureus isolates was performed using specific primers based on PCR. The results revealed that S. aureus isolated from cooked food had the highest percentage of the isolates producing the enterotoxins A and B. Type A enterotoxin gene showed a higher prevalence than type B gene among cooked food , dairy products and pastry. In conclusion, the results revealed a high prevalence of some classical enterotoxin genes in  multi-drug resistant S.aureus isolated from different sources of food, which can cause food-poisoning  and, consequently, a potential serious problem for public health.


2019 ◽  
Vol 82 (2) ◽  
pp. 325-330 ◽  
Author(s):  
WANWAN LIU ◽  
XIAONAN WANG ◽  
JING TAO ◽  
BANGSHENG XI ◽  
MAN XUE ◽  
...  

ABSTRACT This study aimed to establish a multiplex PCR detection system mediated by “universal primers,” which would be able to determine whether mutton meat contained nonmutton ingredients from rats, foxes, and ducks. Based on the sequence variation of specific mitochondrial genes, nine different multiplex PCR primers were designed, and four kinds of meat products were rapidly identified by electrophoresis using an optimized multiplex PCR system based on the molecular weight differences of the amplified products. Multiplex PCR applications optimized for meat food source from food samples for testing was used to verify the accuracy of the identification method. The results showed that the primers in multiple PCR system mediated by universal primers could be used for the rapid identification of rat, fox, duck, and sheep meat in mutton products, and the detection sensitivity could reach 0.05 ng/μL. The identification of food samples validated the practical value of this method. Therefore, a multiplex PCR system mediated by universal primers was established, which can be used to quickly identify the origin of animal ingredients from rats, foxes, and ducks in mutton products.


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