2. Being Sick
Of course the body will really react by being sick. This is an attempt to try and purge your body of the bacteria or the virus, just as it tries to purge itself of alcohol or other toxins. The vomiting is not actually caused by the bacteria per say but rather it is caused by the body itself in reaction to the bacteria.
This is nothing to be worried about but if you vomit repeatedly and are unable to keep fluids down then you may be at risk of dehydration and should see a doctor soon. Drink as much water as you can the rest of the time.