My last two batches have been infected with a bacteria infection. I'm curious what species of bacteria could survive the alcoholic conditions of the brew? The first infected batch appear to have colonies post-bottling, coating the inside of the PET bottles with what appear to have the size and spread of typical Lactobacillus colonies. My second infected batch had a large colony in the area of the Krausen Collar in primary fermentation - seemed to be more shiny and gooey reminiscent of an aerobic bacteria of some sort - this had a somewhat noticeable effect on the smell and taste.
Lactobacillus breques is the most common one, followed by Pectinatus spp. The latter and Zymophilus can grow in pH between 4.3 and 4.6, with ethanol below 5%.
Other ones are:
BTW 'spp.' is short hand for 'species'. As in "Lactobacillus spp." means all kinds of Lactobacillus and his brother will be found as contaminants.
A good article about bacteria and beer brewing can be found in this link:
Its an article in a blog about sour brewing. But if one scrolls down halfway(ish) the author discusses other biological agents and their preferred brew environments - and the sort of tastes/odours associated with them.