## Matt’s Holiday Nightmare

Cholera is a disease caused by **very rapidly multiplying bacteria**. In this module you will learn how to **measure the growth rate **of this bacterium, and why a **log-transformed graph** helps us a lot more than a regular one. And once we know the growth rate you will be able to work out what might have been the source of Matt’s symptoms.

## Matt Gets Messy: In search of Exact Doubling Time

In Matt’s Holiday Nightmare (above), you explored the growth rate of bacteria using some very easy numbers. But life is not so easy, and Matt wants to know _exactly_ how long it took for the bacteria to reach an infective dose. ** You will learn how to handle exponential numbers and how useful logs are** for predicting how rapidly a bacterium can divide.

## Methods for Counting Bacteria

We want to track how quickly the bacteria that cause cholera could have multiplied in the water or food that Matt consumed, but how? Compare **different methods of measuring bacterial populations** and **pick the best one** for the task at hand.

## Viable Plate Count… or, how to count to a million

We’re gonna get serious about counting in this module, with a bit of estimating and multiplying thrown in just to keep things interesting. **Practice all the steps involved in doing viable plate count by serial dilution**. So many ways to practise it will knock your socks off!