---
author: Sam White
toc-title: Contents
toc-depth: 5
toc-location: left
date: 2011-01-12 05:14:02+00:00
layout: post
slug: bacterial-dilutions-determination-of-colony-forming-units-from-gigas-bacterial-challenge-from-earlier-today
title: Bacterial Dilutions - Determination of Colony Forming Units from Gigas Bacterial
  challenge (from earlier today)
categories:
  - 2011
  - Miscellaneous
tags:
  - bacterial challenge
  - CFU
  - colony forming units
  - Crassostrea gigas
  - Pacific oyster
  - Vibrio vulnificus
---

All dilutions were performed with 1x LB+ 1%NaCl. 100uL were plated of all dilutions (see below) on 1xLB+1%NaCL plates. Plates were incubated O/N @ 37C. Colonies will be counted tomorrow to determine CFU for each sample.

Plated 100uL of:

V.vulnificus, t=0, 1:1,000,000 and 1:10,000,000

V.vulnificus H2O sample, t=1 & 3, 1:10,000 and 1:1,000,000

V.tubiashii, t=0, 1:1,000,000

Control H2O sample, t=1 & 3, Undiluted

Samples tubes containing bacteria and dilutions were stored @ 4C.

**_UPDATE 20110112**_: 

Colony counts and calculations

V.vulnificus 0hr = Both dilutions produced a total lawn of bacteria. Uncountable. Will plate higher dilutions, but this will now only be a rough estimate due to the time that has passed. 

---UPDATE---

New serial dilutions (90uL plated) of V.vulnificus 0hr were performed, down to 10^12. The only countable plate was the 10^12 dilution.

V.vulnificus 0hr = 10^12 dilution x 410 CFU = 4.1x10^14 CFU/90uL = 4.56x10^12 CFU/uL x 8x10^6uL (8L H2O in oyster tank) = 3.64x10^19 CFU total in oyster tank/8L = 4.56x10^18 CFU/L

V.vulnificus 1hr = 1:1,000,000 dilution x 48 CFU = 4.8x10^7 CFU/100uL = 4.8x10^5 CFU/uL x 8x10^6uL (8L H2O in oyster tank) = 3.84x10^12 CFU total in oyster tank/8L = 4.8x10^11 CFU/L

V.vulnificus 3hr = 1:1,000,000 dilution x 23 CFU = 2.3x10^7 CFU/100uL = 2.3x10^5 CFU/uL x 8x10^6uL (8L H2O in oyster tank) = 1.84x10^12 CFU total in oyster tank/8L = 2.3x10^11 CFU/L

Control H2O (no significant growth occurred O/N, just tiny colonies; continued incubation to allow colonies to increase in size for easier counting)

Control H2O 1hr = Undiluted 146 CFU/100uL = 1.46 CFU/uL x 8x10^6uL (8L H2O in oyster tank) = 1.168x10^7 CFU total in oyster tank/8L = 1.46x10^6 CFU/L

Control H2O 3hr = Undiluted 106 CFU/100uL = 1.06 CFU/uL x 8x10^6uL (8L H2O in oyster tank) = 8.48x10^6 CFU total in oyster tank/8L = 1.06x10^5 CFU/L

V.tubiashii 0hr = 1:1,000,000 dilution x 31 CFU = 3.1x10^7 CFU/100uL = 3.1x10^5 CFU/uL x 5x10^4 (50mL total volume of bacteria) = 1.55x10^10 CFU total V.tubiashii
