Medical Microbiology & Diagnosis

Staphylococcal Enterotoxin B (SEB) is one of the potent enterotoxins produced by certain strains of Staphylococcus aureus bacteria. In the present context of its use as bio-terror agent, it is imperative to develop simple to use and rapid detection systems as well as therapeutic vaccines to detect SEB and protect against SEB intoxication. In the present study, recombinant staphylococcal enterotoxin B, produced as a NH2-terminal histidine hexamer fusion protein, expressed in heterologous expression system, was tested for its diagnostic potentials. His6-tagged SEB was immunogenic for IgG in mice and rabbits, either singly or in combination with adjuvant. Antigenic authenticity of the recombinant SEB to native SEB was confirmed by antibody-based capture detection assays across different host species. Using recombinant SEB as bound target, a sandwich ELISA was developed and utilized for detection of SEB in vitro and in vivo. The ELISA described here can be a useful tool for detection of SEB intoxication as well as infection due to SEB producing S. aureus bacteria. Data indicated potentials of recombinant SEB in diagnosis and vaccine development.

Background: Hands and cell phones are the major source of cross- transmission of urinary tract infections. The
aim of our study was to isolate, identify and evaluate Gram-negative bacteria from them.
Method: This study was conducted in visiting area of Civil Hospital Karachi, Pakistan. Analysis was done by 50
wet sterile cotton tipped swabs, 25 each from mobile phones and hands of their owners. Samples were transported
in a Cary Blair transport media, Swabs were streaked on Nutrient agar, Blood agar and Macconkey agar. Organisms
were identified by cultural, biochemical and microscopic characteristics. Frequency of bacterial species observed
was evaluated.
Results: A total of 25 samples were collected from cell phones, out of 3 samples were positive cell phones
were collected from 50 persons having age between 28 to 43 and standard deviation 14.8052 ± 22.222 rang. Rate
of bacteria found Serretia (24%), E. coli (24%), Pseudomonas (12%), Klebsiella (12%), Shigella (8%) and Proteus
(12%). While cell phones were contaminated by E. coli, Klebsiella and Serretia with percentage of 54, 31 and 15
respectively.
Conclusion: Mobile phones and hands are reservoir of pathogenic organisms. Patient attendants in hospitals
and visitors are more susceptible to nosocomial infections through exchange of mobile phones as their hands and
mobile phones were contaminated by microbes causing urinary tract infections. To prevent infectious diseases
hospitals should have enough outlets for washing hands with an ample supply of water. Hygienic practice of keeping
hands clean and frequent mobile disinfection practices may help to break transmission cycle of pathogenic bacteria.