[show abstract][hide abstract] ABSTRACT: The purpose of this study was to identify enterotoxin genes from isolates of coagulase-negative staphylococci and coagulase-positive staphylococci obtained from dairy products, responsible for 16 outbreaks of food poisoning.
From the pool of 152 staphylococcal isolates, 15 coagulase-negative and 15 coagulase-positive representatives were selected for this study. The 15 coagulase-negative isolates were tested for the presence of coa and femA genes, which are known to be characteristic of Staphylococcus aureus. After testing for enterotoxin genes by polymerase chain reaction (PCR), the 30 selected isolates were tested for the presence of toxin by immunoassay.
Seven of the coagulase-negative isolates amplified the coa gene and were subsequently reclassified as coagulase-positive. Twenty-one of 30 selected isolates had staphylococcal enterotoxin genes and most of these produced toxin as well. The most frequently encountered enterotoxin genes were sea and seb. Among eight coagulase-negative isolates, five had enterotoxin genes, all of which were found to have detectable toxin by immunoassay.
The results from this study demonstrate that coagulase-negative as well as coagulase-positive staphylococci isolated from dairy products are capable of genotypic and phenotypic enterotoxigenicity. Furthermore, these data demonstrate that PCR is a sensitive and specific method for screening outbreak isolates regardless of coagulase expression.
International Journal of Infectious Diseases 08/2008; 12(4):410-5. · 2.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: In the present work, the effect of narrow-band ultraviolet B (UVB) phototherapy on a cutaneous microbial population was evaluated in patients with atopic dermatitis (AD) and compared with control patients (vitiligo).
Count, isolation and identification of cutaneous microbiota from anticubital fossa were performed in 10 controls and 10 AD patients, both submitted to similar levels (P > 0.05) of UVB phototherapy (4.3 +/- 0.9 and 4.3 +/- 0.8 accumulated joules, respectively). Additionally, Staphylococcus aureus isolates were screened for the production of exotoxins.
The total and staphylococcal cutaneous microbial population levels were higher (P < 0.05) in AD patients than in the controls. All these population levels decreased (P < 0.05) for both AD and control patients after UVB phototherapy, which also decreased the SCORAD for AD patients. All patients with AD and 50% of controls were carriers of S. aureus, and harboured the bacteria simultaneously on skin and anterior nares. All of the S. aureus strains recovered from AD patient skin produced toxin and the B type was the most frequently detected (70%), followed by C (20%) and A (10%) toxins. Only 40% of the S. aureus isolates from control patients produced toxin. After UVB treatment, microbial population levels of AD patients were similar (P > 0.05) to the ones found in control patients before phototherapy, and toxin production ability of S. aureus isolates decreased drastically.
The results of the present study show the beneficial effect of UVB phototherapy on AD and suggest that this may be attributable not only to reduction of skin surface bacteria but also to the suppression of superantigen production from S. aureus.
Journal of the European Academy of Dermatology and Venereology 11/2006; 20(9):1114-20. · 2.69 Impact Factor
[show abstract][hide abstract] ABSTRACT: Staphylococcal enterotoxins (SEs) are the second most common causal agents of food poisoning throughout the world. Staphylococcal enterotoxin B (SEB) is one of the most potent and a listed biological warfare agent. Therefore, its quick, accurate and sensitive detection is of paramount importance. But availability of sensitive and specific antibodies against SEB is the major bottleneck in the development of an immunodetection system. Therefore, in the present study seb gene was cloned and expressed in a heterologous host resulting in a yield of 92 mg pure toxin per litre of culture broth after Ni-NTA affinity purification. Antibodies raised against the recombinant toxin did not cross react with related enterotoxins and organisms that can gain access in the food. Further, a sandwich ELISA was developed to detect SEB after extraction from artificially spiked food samples like milk, orange juice, skim milk and khoya. The sandwich ELISA was able to detect SEB in the range of 0.25 to 0.49 ng/ml or g of food. The detection system developed in the present study is at least as specific and sensitive as other commercially available kits which use monoclonal antibodies.
Indian Journal of Microbiology 06/2012; 52(2):191-6. · 0.46 Impact Factor
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