Thursday, July 13, 2006

Helicobacter pylori arrived

The one of the biggest challenging bacterium I'd manage finally arrived today. This extremely fastidious bug - Helicobacter pylori is such a fragile thing that anyone who handle it would need to spend more care on it: 1. Need highly nutritious media. Probably BHI (Brain Heart Infusion) or Columbia media is a choice. 2. Like other microaerobes, Helicobacters also need blood (or equivalent) to quench the damage from oxygen and its derivatives (free radicals, hydrogen peroxide, etc). So defibricated sheep blood or horse blood would be unavoidable. 3. Due to its slow growth, I'll have to incubate it much longer than other genus. Roughly 3-7 days. 4. During the long term incubation, contamination should be an issue; especially I'm also handling other enterbacters, which are major competant cultures of Helicobacters. Suitable antibiotics would also be required. 5. Last but not least, need to keep high humidity. It's reported that a water activity of at least 0.95 is required for its growth. Under such a high humidity, fungi would be a big concern. (So germicides have to take into account...) What I've decided to use for the media is Columbia Horse Blood HP (shortly CHBHP), which is reported to be superior for culturing Helicobacter pylori in Japan (fast growth, low contamination). The problem is... the columbia agar and horse blood we've ordered haven't arrived yet...(actually the HP culture was supposed to be arrive tomorrow, but who knows it arrives TODAY...) Now here is a big dillema. This afternoon I was told that the two stuff would arrive tomorrow. So, should I wait till tomorrow so that I can use the freshly-made CHBHP, or should I culture and freeze the cells today with BHI (Brain Heart Infusion) so that those cells wouldn't transform into coccoid form or even die? Eventually I decide to postpone one day and see if the reagents would arrive tomorrow.

No comments: