Yasuki Ogawa

Interaction of Salmonella typhimurium and Salmonella enteritidis with polystyrene does not correlate with virulence in young chickens

Salmonella typhimurium and Salmonella enteritidis are the most frequently isolated serotypes in human and animal Salmonella infections. The in vitro surface colonization characteristics of S.typhimurium L1388 and S. enteritidis L1225 on hydrophobic surfaces were assessed with a view to understanding their surface preference in relation to in vivo virulence. Although both S. typhimurium and S. enteritidis preferentially colonized polystyrene under normal nutrient-rich growth medium, S. typhimurium formed significantly (P < 0.05: P = 0.000008) smaller amounts of biofilm than S.enteritidis. The biofilm formed on polystyrene was optimum at different times, 200 min and 400 min for S. enteritidis and S. typhimurium, respectively. S. typhimurium also formed significantly (P < 0.05)less biofilm than S. enteritidis when the growth medium was supplemented with 100 mM each ofeither D-(+)-mannose (P = 0.0001), D-(+)-glucose (P = 0.0005), D-(-)-mannitol (P = 0.00002) or xylose (P= 00009). Biofilms formed by S. enteritidis following growth in sugar-supplemented medium were not significantly different from that following growth in non-supplemented medium; but significant (P <0.05) reduction in amounts of biofilm formed by S. typhimurium were produced by only mannitol (P =0.0008) and xylose (P = 0.00004). Growth in sodium chloride-supplemented medium resulted in significantly (P < 0.05) less biofilm formed by both S. typhimurium (P = 0.0084) and S. enteritidis (P =0.0002); even though the quantity formed by S. typhimurium was significantly (P < 0.05: P = 0.0098) more than that by S. enteritidis. Both strains formed significantly less biofilm on polystyrene when cultured in a starvation medium for 24 h. They also do not differ significantly from each other in their extent of adherence to polystyrene and 14-day chick mortality. Overall, the interaction of S.typhimurium and S. enteritidis with polystyrene does not correlate with virulence in young chickens

Analysis of the protein profiles of the antibiotic-resistant Salmonella typhimurium definitive phage type (dt) 104

The emergent Salmonella typhimurium definitive phage type (DT) 104 is of particular global concern due to its frequent isolation and multiple antibiotic resistances. There is thus a need to know the kind of proteins expressed by S. typhimurium DT104 so as to provide a basis for developing an intervention. This study examined the protein profiles of a few isolates of S. typhimurium DT104 and a non-DT104 strain S. typhimurium L1388 (ST). Crude SDS-soluble whole cell and outer membrane protein (OMP) extracts revealed similar protein profiles for both phage types. A single major protein band (28.4 kDa) was observed in periplasmic fractions from both phage types. However, proteins released into growth medium was variable; one of the DT104 isolates had common proteins with the non-DT104 strain ST. Similar SDS-soluble whole cell protein profiles were observed for both phage types grown in a low-iron Medium A at 37oC; but a 38.5 kDa protein (observed in TSB-grown cells) was observed only in the temperature-tolerant DT104 isolate. The protein contents of cell-free ultracentrifuge supernatants of sonically disrupted cells of each of the DT104 isolates were significantly (P African Journal of Biotechnology Vol. 4 (7), pp. 727-737, 2005