Help PLEASE. :-)

[lincsloon]

Hiya,

I am new to this forum so feel a bit cheeky asking for help first off but my brain is in totally blonde mode.

I am a third year degree student and my project is in novel antimibrobial products... I plan to look at levels of inhibition at depth thus simulating wound depth but my mental block is with the methodology. I plan to puncture agar at different depths, inocculate these depths with MRSA and then apply the antimicrobial and asses its properties from this, but i cant think of a standard peice of equipment from which to do this as i need something deep like a beaker but it needs to be able to be sealed and the flatter the better for visable colony counting... ie a petri dish that is square, stands on its side and opens at the top... probably not making alot of sense here but if you understand my waffle then all help ideas appreciated... and if you dont get my waffle, then hello and thankyou for reading and great forum!!

 

Lori. x

[Superbug]

Are you planning to count colonies at the different depths? Because I'm not sure you'll be able to differentiate single colonies, although you'll be able to say whether the inoculum grew or not. I'd just use test tubes and have a single tube per experiment. Do you think antibiotics will work differently at different depths?

[SkepticLance]

I am very fond of Schott bottles. They have, of course, a heat resistant screw top plastic cap, which seals perfectly. Fill it with agar and autoclave the entire bottle. It remains sterile until the cap is removed.

 

If a smaller container is needed, then a 20 ml McCartney bottle will do the same, with its screw cap.

[CharonY]

Also you can use cell culture bottles. Essentially I would suggest to simply scan the sites of local manufacturers for laboratory glass or plastic wares. However, you are aware that you will have several parameters at once that affect bacterial growth?

What you intend to do sounds much like deep agar shakes, which are routinely done to incubate anaerobic bacteria. Within the agar you may get an oxygen gradient and a resulting unequal growth. Also the way you puncture the agar will limit the possible spread of the bacterium. Also depending on how you apply the ABs you may get diffusion effects. And also as mentioned above how do you intend to count the bacteria? If you don't spread them but only puncture the agar you won't get countable colonies.

[DarkStar]

try using microtitre plate...you can analyze more sample in one go.

I think they are cheap. As far as incubation is concerned if you have anerobic chamber or CO2 incubator for anerobic conditions.

Advantages of doing it.

1. you can analyze more samples.

2. chances of contamination are low

3. Quantify you result with less pain

[jorge1907]

You should have some technical rationale - some reason to think this approach has any value.

What is the variable here - oxygen tension? If so - do some homework (ala pubmed) - does staph grown under anaerobic or microaerophilic conditions show differential sensitivities vs. the antimicrobial you plan to use? And just what "novel antim icrobial" do you have in m ind?