Streptococcus zooepidemicus (SZ) is an aerotolerant bacteria and its ability to survive under reactive oxidant raises the question of the existence of a defense system against oxidative stress. As a characteristic of lactic acid bacteria, Streptococcus lacks an ordinary anti-oxidative stress enzyme, catalases and an electron transport chain. Whether this bacterium resists oxidative stress prior to an exposure to a higher level of an oxidizing agent H2O2 in hyaluronic acid fermentation is not known. This paper describes that Streptococcus cells, once treated with lower concentrations of H2O2 (i.e. 0.25, 0.50 and 1.0 mM) at least, were prepared for a subsequent higher concentrations of H2O2 such as 20.5 and 100 mM. At low concentrations (i.e. 0.25, 0.50 and 1.0 mM), H2O2 was found to act as a stimulant for HA synthesis, but it became toxic if presented at a very high level (100 mM H2O2). The highest HA yield to glucose consumed (YHAtotal/glu) was 0.017 gg-1 for the cells pre-treated with 0 mM of H2O2, and then exposed to 20.5 mM H2O2. Thus, this implied that this bacteria might possess a defense mechanism against oxidative stress and that this system was inducible.
Gorham disease (GD) is an extremely rare disorder that is characterised by massive osteolysis of the affected bone with unknown aetiology and an unpredictable prognosis. Additionally, no standard treatment is available for GD. This article describes a case report of a 61-year-old Malay woman who was diagnosed with GD of the anterior mandible without a prior history of trauma. She presented with pain and mobility of the dentoalveolar segment for 3 months. The radiographic findings showed "floating teeth" with widening of the periodontal ligament space and localized area of bony destruction. Histopathologically, there was proliferation of numerous dilated endothelial-lined channels within the intertrabecular tissue. Some areas of bone were replaced by fibrous connective tissue giving rise to the appearance of a benign fibroosseous lesion. The patient was managed with simple removal of the affected bone segment under local anaesthesia, followed by prosthodontic rehabilitation. Healing of the surgical site was uneventful, and no recurrence was reported at the 3-year follow-up.
Streptococcus zooepidemicus (SZ) is an aerotolerant bacteria and its ability to survive under reactive oxidant challenge raises the question of the existence of a defense system. Thus growth, hyaluronic acid (HA) and hydrogen peroxide (H2O2) production by SZ in the presence of increasing concentration of Mn2+ were studied. The results suggested that the tested strain supported growth and HA production in cultures treated with 1 and 10 mM of Mn2+ regardless of H2O2 presence in the medium. This showed that SZ have acquired elaborate defense mechanisms to scavenge oxygen toxicity and thus protect cells from direct and indirect effect of this radical. In contrast, cells treated with 25 mM Mn2+ were sensitive, in which, the HA production was reduced considerably. Thus showing that the oxygen scavenger systems of the cells may be fully saturated at this concentration.