Expert: Florence M Rollwagen - 1/5/2009

Question
QUESTION: hello...
can you give me the details about the parameters of water that will be affected when vibrio cholerae is present in water? is there any chance to manipulate the percentage of vibrio cholerae in a given sample of water based on the parameters of water???

ANSWER: Hi Aarthi:  Thanks for your question.  I don't know what you mean by "parameters" of water.  Vibrio is a bacteria, and will be killed by boiling, you can also eliminate the bacteria by filtering through an 0.4 micron filter.  You can also make the water too acid for the bacteria to survive.  Somehow, I don't think that's the answer you're looking for.

Please clarify and I'll try to help you.

FM Rollwagen, PhD

---------- FOLLOW-UP ----------

QUESTION: Thank you.
By "parameters" I meant the pH content of water, Hardness, Turbidity, BOD, COD and the presence of other chemicals like Mercury, Lead and so on. so if the bacteria is present in water, will there be any change in these parameters. if so what are they? And how do i find out the percentage of this bacteria present with the parameters? is there any way out??

ANSWER: Hi again, Aarthi:  The easiest way to determine bacterial counts in a sample of water is by membrane filtration.  Take a known volume of water (say a liter) and run it through a filter apparatus.  Then take out the filter and set it on a petri dish with nutrient agar.  The colonies will grow and you can count them.  If you deliberately inoculate water under various conditions (parameters) then you can determine if the bacteria will survive.  If you're taking environmental water then you will have to identify how many cholera organisms vs other bugs are present in your filtrate.  A much bigger problem.

Here's the method:
http://www.corn.org/methods/I-B.pdf
http://filebox.vt.edu/users/chagedor/biol_4684/mfcoli.html
http://www.hach-lange.at/shop/action_q/download%3Bdocument/DOK_ID/7604/type/pdf/

Hope this helps!  Write back if you have more questions.

FM Rollwagen, PhD





---------- FOLLOW-UP ----------

QUESTION: thanks a ton.
The problem is that a team of four of us have decided to make a hand-held device that could detect the bacterium in water. so that the incubation period and the whole lot of biological process that takes more than two days can be avoided and reports can be generated immediately if the water is contaminated or not. is this feasible?? as the epidemic is rate is really high, we thought, we could provide a better solution that could save many lives.

Answer
Hi again, Aarthi:

Well today is your lucky day!  I worked for the Navy for many years in the field of rapid diagnosis.  There is urgent need for the detection of infectious agents in the environment or in patients, since, as you know, traditional methods take too much time.  These efforts have been accelerated since the anthrax scare a few years ago.

Much of the effort has been directed at two methodologies:  detection by antibody (ELISA or EIA, SNAP) and detection by real time PCR or another DNA detection device.

A hand held device is really far from our abilities right now.

Here is a good review that will get you started:
http://smj.sma.org.sg/3503/3503ia2.pdf

Here are a couple more articles that may be interesting:
http://www.sciencedaily.com/releases/2006/02/060202180046.htm

http://www.labmeeting.com/papers/public_citation/28494358/a_novel_dna_microarray

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1862064

http://news.thomasnet.com/fullstory/467468

If you want to search the Net yourself, look for: “rapid diagnosis”, you can look up each of the techniques I listed above for more information.

Hope this helps!  Write back if you have more questions.

FM Rollwagen, PhD