Molecular detection of Staphylococcus aureus enterotoxin genes isolated from mastitic milk and humans in El-Behira, Egypt

Abstract

Background and Aim: Milk is a chief source of many nutrients. However, we must also bear in mind that it is a potential source for many cases of food poisoning. This study was conducted to investigate the prevalence of cow mastitis and evaluate the presence of enterotoxins and antibiotic resistance patterns in Staphylococcus aureus isolated from milk and contact humans in El-Behira Province, Egypt. Materials and Methods: A total of 680 milk samples from 170 cows and 86 human samples consisting of 43 hand swabs and 43 nasal swabs were analyzed. The milk samples were subjected to the California mastitis test. Results: The general occurrence was 23.1% (157/680) where 48 quarters had clinical mastitis and 109 had subclinical mastitis. Subsequently, S. aureus was isolated in Baird-Parker agar where typical and atypical colonies were selected and submitted to coagulase and complementary tests. Out of 48 samples of mastitic milk studied, 16 (33.3%) showed contamination by S. aureus whereas 109 samples of subclinical mastitis showed contamination in only 18 (16.5%). On the opposite hand, of the 86 human samples, 33 revealed S. aureus contamination, corresponding to 38.37% of the samples. Furthermore, multiplex polymerase chain reaction targeting nuc and the staphylococcal enterotoxin-encoding genes sea, seb, sec, sed, and see were performed after culture, revealing that 88.2% (30/34) of milk samples and 93.9% (31/33) of human samples were variably positive to those genes. Conclusion: The use of nuc gene based PCR is an accurate and rapid method for S aureus isolates detection. A high prevalence of multiple drug-resistant isolates of S. aureus recovered from both human and milk represents further evidence for possible veterinary hazards as well as public hazards, especially to those that consume milk from this region.

Effect of Temperature on the Expression of Classical Enterotoxin Genes among Staphylococci Associated with Bovine Mastitis

“…In addition, Piechota et al [ 17 ] reported that sec was the most prevalent SE gene among CNS. Various studies in different regions have also revealed that sea was the most common bovine mastitis-associated SE gene among S. aureus [ 25 , 26 ] and CNS [ 4 , 21 ]. A recent study revealed that sec is an important virulence factor of S. aureus that causes inflammation and tissue damage to the infected mammary gland [ 27 ].…”

Detection of New Staphylococcal Enterotoxin Encoding Genes in Staphylococcus aureus Isolated from Animals and Humans in Yogyakarta

“…S. aureus, which is thought to be highly infectious and is easily transferred during milking, can be produced in significant quantities by both subclinical and clinical mastitis. In El-Behira, Egypt, 44.2% of hand swabs from people who seemed to be in good health and had contact with cows were positive for S. aureus [19].…”

“…Those who handle food are seen to be a potential cause of food contamination, either directly or indirectly [19]. Laboratory investigation of stool samples from patients, all food scraps, and some kitchen and hand swabs from food handlers by Umeda et al, [20] isolated a strain of S. aureus containing the new SE/SEls gene (seg, sei, sem, sen, seo, and selu) sans classical SEs.…”

Identification of nuc nuclease and sea enterotoxin genes in Staphylococcus aureus isolates from nasal mucosa of burn hospital staff: a cross-sectional study

“…Enterotoxin profile genes were found in 64.7% of the milk samples, 63.2% of the hand samples, and 64.3% of the nasal samples. Sea was the most prevalent gene in all sample types [ 21 ]. In Goudarzi et al.…”