Staphylococcal enterotoxin A gene-carrying Staphylococcus aureus isolated from foods and its control by crude alkaloid from papaya leaves.

Abstract

Staphylococcus aureus is a known pathogen causing intoxication by producing enterotoxins in food. Staphylococcal enterotoxin A is one of the enterotoxins commonly implicated in staphylococcal food poisoning. The ability of crude alkaloid extract from papaya leaves to inhibit the growth of S. aureus and staphylococcal enterotoxin A synthesis was investigated. Staphylococcal enterotoxin A gene-carrying S. aureus was isolated from raw milk and ready-to-eat foods. Crude alkaloid was extracted from ground, dried papaya leaves using ultrasonic-assisted extraction, and a MIC of the alkaloid was determined by the broth macrodilution method. Furthermore, S. aureus isolate was exposed to the crude alkaloid extract at one- and twofold MIC, and the expression of sea was subsequently analyzed using a quantitative reverse transcription real-time PCR. Ten isolates of S. aureus were obtained, and nine of those isolates were sea carriers. The yield of crude alkaloid extract was 0.48 to 1.82% per dry weight of papaya leaves. A MIC of crude alkaloid to S. aureus was 0.25 mg/ml. After exposure to the alkaloid at 0.25 and 0.5 mg/ml for 2 h, a significant increase in cycle threshold values of sea was observed. The sea was expressed 29 and 41 times less when S. aureus was exposed to crude alkaloid at one- and twofold MIC, respectively. This study revealed that crude alkaloid of papaya leaves could control staphylococcal enterotoxin A gene-carrying S. aureus by suppressing the expression of sea, in addition to the ability to inhibit the growth of S. aureus. The expression of sea was successfully quantified.

• Authors: Lita Handayani, Didah Nur Faridah, Harsi D Kusumaningrum
• Journal: Journal of food protection (J Food Prot) Vol. 77 Issue 11 Pg. 1992-7 (Nov 2014) ISSN: 1944-9097 [Electronic] United States
• PMID: 25364936 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Alkaloids
• Enterotoxins
• Plant Extracts
• enterotoxin A, Staphylococcal

Topics

• Alkaloids (pharmacology)
• Animals
• Carica (chemistry)
• Cattle
• Enterotoxins (metabolism)
• Fast Foods (microbiology)
• Milk (microbiology)
• Plant Extracts (pharmacology)
• Staphylococcus aureus (drug effects, genetics, isolation & purification, metabolism)