Biotyping and enterotoxigenicity of coagulase-positive and coagulase-negative staphylococci isolated from different raw meat.

BACKGROUND: Staphylococcal enterotoxins (SEs) are produced in foods under favorable conditions and considered a potential biological threat. AIMS: The study was performed to detect enterotoxigenic genes of A and B in coagulase-positive (CPS) and coagulase-negative staphylococci (CNS) to evaluate biotypes and antibiotic resistance of isolated Staphylococcus aureus from different meat. METHODS: A total of 160 meat swab samples were collected from lamb, water buffalo, cattle, and chicken carcasses. Presumptive colonies on Baird Parker agar were subjected to biochemical identification, including Gram staining, catalase, oxidase, and coagulase activity. Relevant colonies separately were subjected to the polymerase chain reaction (PCR) assay for identification of Staphylococcus genus, enterotoxigenic genes (sea and seb) and the thermonuclease gene (nuc) specific for the S. aureus. The antibiotic susceptibility test was also carried out using five antibiotics. RESULTS: Totally, 150 Staphylococcus spp. were isolated from the samples among which 135 (90%) isolates harbored sea gene, meanwhile, none of the isolates contained seb gene. Twenty-five S. aureus confirmed by PCR from which 15 isolates (60%) belonged to host specific (HS), 7 isolates (28%) belonged to non-host specific (NHS) biotypes, while 3 isolates (12%) were non-typable. Overall, 68%, 56%, 16%, 12%, and 8% of isolates were resistant to penicillin, trimethoprim, gentamicin, oxacillin, and erythromycin, respectively. CONCLUSION: The meats provided from this area were contaminated with enterotoxigenic and antibiotic-resistance staphylococci, which can threaten the health of the consumers. The study showed that not only CPS contain enterotoxin A gene, but also CNS isolates possess this gene, especially in buffalo meat, and thus they are recognized as potential hazards in different meats.

Anticonvulsant activities of Sambucus nigra.

OBJECTIVE: Sambucus (S) spp. is reported to possess a variety of activities and has been used in traditional medicine for many years. In spite of CNS activity of this genus, nothing is known about the anticonvulsant activity of S. nigra. MATERIALS AND METHODS: Anticonvulsant activities of methanolic extracts of bark, fruit and leaf of S. nigra at doses of 250, 500 and 1000 mg kg-1 were determined by pentylenetetrazole (PTZ) induced and maximal electroshock (MES) induced convulsions in mice. RESULTS: Normal saline treated mice showed tonic hind limb extension for a duration of 6.58 ± 1.24 s in MES model. Administration of extracts significantly and dose-dependently increased the delay of the onset of seizures and decreased significantly the duration of tonic hind limb extension. Bark extract at 500 and leaf extract at 1000 mg kg-1 gave 100% protection against seizures. They inhibited induction of convulsion and gave 100% protections against mortality. PTZ (100 mg kg-1) induced tonic seizures in all of the control mice. Pretreatment with leaf extract at 500 and 1000 mg kg-1 significantly decreased duration of tonic hind limb extension (p < 0.05 and p < 0.001). CONCLUSIONS: GABA receptors were involved in epilepsy. Reduction of mortality and increase the onset of convulsion in MES model was comparable with that of diazepam. Extracts might possibly be producing an antiepileptic action by increasing the level of GABA.

Determination of Aflatoxin M1 Contamination and Integrity as well as Credibility.

Aspergillums can produce and secrete directly aflatoxin M1. During the previous decade several papers pertaining to aflatoxin M1 have been published in different journals. Not mention of their more or less scientific aspects, they have fundamentally some problems in different features. In this paper we are going to have a bird's eye view on some articles published on this topic. It is suggested that complete research must be performed in order to find out the source of aflatoxin M1 contamination.