Rapid detection of major enterotoxin genes and antibiotic resistance of Staphylococcus aureus isolated from raw milk in the Yazd province, Iran.

INTRODUCTION: Raw milk is a nutrient-rich food, but it may harbour harmful bacteria, such as enterotoxigenic Staphylococcus aureus (S. aureus), which can cause staphylococcal food poisoning. Antibiotic resistance of S. aureus in raw milk can increase the risk of such infections, particularly among susceptible individuals. OBJECTIVE: This study aimed to investigate the prevalence of enterotoxin genes a, d, g, i and j and the antibiotic resistance of S. aureus isolated from raw milk samples. METHODS: During a 6-month sampling period, 60 raw milk specimens were obtained from diverse locations in Yazd province, Iran. Antibiogram profiling was conducted via the disc diffusion method. In addition, staphylococcal enterotoxin (SE) genes a, d, g, i, and j were detected through real-time PCR analysis. RESULTS: Bacteriological assays confirmed the presence of S. aureus in 11 samples (18.3%). All isolates demonstrated 100% resistance to penicillin G but exhibited sensitivity to vancomycin, while resistance to other antibiotics ranged from 36.4% to 45.5%. The prevalence of enterotoxin genes in these strains showed variable distribution, with sea being the predominant SE (45.5%), followed by sed (36.4%), seg (18.2), sej and sei (9.1% each). CONCLUSIONS: This study discovered the presence of multiple enterotoxins in S. aureus strains obtained from raw milk samples. These strains also demonstrated resistance to a variety of antibiotics. Since enterotoxigenic S. aureus is known to cause human food poisoning, monitoring food hygiene practices, especially during raw milk production, is critical.

Isolation and characterization of the lactobacillus strain from honey and its probiotic properties.

Background and Objectives: The lactobacilli are abundant in honey, helping protect against pathogens and providing antimicrobial properties. This study aimed to isolate lactobacillus species from different honey regions and evaluate their potential probiotic properties. Materials and Methods: Eighty-eight samples were collected from different regions, including the northern, central, and southern areas, and obtained through retail stores. All samples were independently examined for the presence of Lactobacillus using both culture and real-time PCR methods. Probiotic tests were performed on the isolated Lactobacillus strains, including hemolytic activity, bile, acid, and pepsin resistance. Additionally, the antibiotic resistance of the obtained strains was investigated using seven different antibiotics. Results: Thirteen Lactobacillus isolates were obtained from 7 (8.0%) honey samples. Of these, eight isolates were identified as L. plantarum (61.54%), four isolates as L. rhamnosus (30.77%), and one isolate as L. acidophilus (7.69%). All strains were devoid of hemolytic activity, and three isolates (23.07%) were found to be resistant to acid, while 2 (15.38%) showed resistance to bile and pepsin. All isolates were resistant to vancomycin (100%). Additionally, only one strain exhibited resistance to all tested antibiotics. Furthermore, the present study demonstrates a significant association (p-value<0.05) between the presence of Lactobacillus in various regions of Iran. Conclusion: Various factors, such as climatic conditions and geographical location, can influence honey's composition and microbial diversity. Identifying and isolating potential probiotic species in honey could significantly expand their use in the food and pharmaceutical industries, offering numerous health benefits and potential therapeutic applications.