Journal of Advanced Biomedical Sciences

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Background and Objective: Haemophilus influenzae type b (Hib) is a gram negative bacterium and one of the most common causative agents of acute meningitis in infants and less than 5 years old children worldwide. The production of Hib capsular polysaccharide polyribosyl ribitolphosphate (PRP) is important for the production of conjugate vaccines against Hib infections. The aim of this study is the improvement of Large-scale PRP production by Hib.
Materials and Methods: Haemophilus influenzae type b standard strain ATCC10211 was cultivated in 2L fermentors contain 1.5L CY (casaminoacid yeast extract) medium with normal or modified concentrations of glucose, yeast extract, hemin and NAD (nicotinamide adenine dinucleotide). Seed culture of two fermentors was inoculated to 50 L fermentor, separately and range of PRP production and Dry cell weight (DCW) were studied.
Results: Cultivation of Hib in 50L fermentor contained modified CY medium with 6gl-1 Glucose, 2.5 gl-1 Yeast extract, 0.03 gl-1 Hemin and 0.015 gl-1 NAD , with controlled pH at 7.3 and 30% Dissolved oxygen tension (DOT) resulted to about 5.1 gl-1 DCW and 1.16 gl-1 PRP , that was significantly higher than normal CY medium.
Conclusion: In conclusion, by modification in some medium components of CY medium, control of Dissolved oxygen tension and pH, the Large-scale production of PRP is improved. Improvement of PRP production leads to reduce the final cost of Hib conjugate vaccines.

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Background & Objective: Molecular typing is an important tool in surveillance and outbreak investigations of human Salmonella infections. In this study, Subtyping of Salmonella Paratyphi B and C isolates derived from Iranian patients was carried out by RAPD-PCR to assess the extent of genetic diversity of these isolates.

Materials & Methods: Fourteen Salmonella isolates including 6 strains of Salmonella paratyphi B and 8 strains of Salmonella paratyphi C were characterized using RAPD-PCR. Two arbitrary primers, namely OPP-16 and P1254 were used for RAPD analysis and the dendrograms were constructed with NTsys 2.0 computer software.

Results: Both primers showed high discriminatory power in differentiating of the related strains of Salmonella. The dendrograms constructed based on RAPD-PCR profiles (with both primers) involving 14 salmonella strains revealed 4 distinct patterns, indicating that these isolates are genetically heterogeneous. Furthermore, a good correlation was not observed between the serotype and the molecular profiles obtained from RAPD data of the Salmonella isolates.

Conclusion: The findings of the present study verify the usefulness of RAPD-PCR in characterizing and comparing strains of Salmonella Paratyphi B and C.