Stimulation of Staphylococcus aureus Enterotoxins Production Using Radiation and Molecular Techniques for Preparation of Its ELISA kits

Abstract

Staphylococci are the major cause of nosocomial infections. Staphylococcal food borne diseases resulting from consumption of food contaminated with SEs are the second most common cause of reported food-borne illnesses. Symptoms include abdominal cramps, nausea, vomiting (emesis) and diarrhea. The onset of symptoms usually starts between 0.5 and 8 h after ingestion of the contaminated food, and symptoms usually resolve without intervention within 24 h. S. aureus produces a wide variety of toxins including 22 staphylococcal enterotoxins (SEs). Staphylococcal enterotoxin type A (SEA) is the most important which characterized serologically distinct types of staphylococcal enterotoxins. The enterotoxins are the causative agents of staphylococcal food poisoning syndrome. Non-carriers commonly acquire infections through contaminated food or when food handlers who are carriers contaminate food during preparation. This study focused on isolation of Staphylococcus from infected patients and selection of sea producing organisms. - The sixty four staphylococci isolates had been isolated from specimens ranged from wounds, pus, throat, sputum, conjunctiva, urine in addition to stool of patients plagued by symptoms of infection. All isolates were cultured on selective media specific for Staphylococcus spp. and then identified by biochemical tests. The results showed that 62 isolates belonged to S.aureus and two isolates belonged to S. epidermidis.

- Collected staphylococci isolates had been subjected to the sensitivity to cefoxitin (FOX) as an indicator of methicillin resistance (MR). Fourty one; S. aureus and one; S. epidermidis out of the sixty four isolates were found to be methicillin resistant. The effectiveness of other commonly used antibiotics towards the fourty two MRS was tested, the results indicated that only one isolate (2.4 %) was sensitive to levofloxacin and teicoplanin. Also, 4 (9.5%), 5 (11.9%), 6 (14.2%), 7 (16.6%), 8 (19.0%) and 10 (23.8%) were sensitive to gentamicin, amikacin,, rifampin, chloramphenicol, erythromycin, trimethoprim/sulfamethoxazole respectively. On the other hand, among the 42 MSR, eleven isolate (26.1 %) were found to be resistant to vancomycin (VRSA) (last choice in treatment). - Ent A gene was detected by PCR using specific primers, PCR was carried out for 64 specimens of DNA extracted from the isolated staphylococci as well as the DNA extracted from reference strain. The target gene was detected in reference strain, nineteen isolates of S.aureus and one isolate of S.epidermidis.