Bad bacteria isn't likely to add fusels. That 'hot' flavor is fusel alcohol that if consistent is usually a sign of too high of fermentation temps, but if this was just one bottle of many then the culprit it could be an accidental overdose of priming sugar.
If you dissolved priming sugar in your batch when you bottled it could be a case of the sugar not being equally distributed or not fully dissolved and that bottle happened to be one of the last ones bottled and had a little more sugar in it. If you used carb tabs or similar chalk it up to an anomaly.
Generally speaking when there is one inconsistent issue with anything in the brew process, it is extremely difficult to pin point the cause. You will likely change something unnecessarily and create more problems. I try to avoid making wide sweeping process changes unless I notice something that is systemic.
On Tap: Blonde Ale, Apfelwein, Cinnamon Apfelwein, Amber Ale, Irish Red
Bottled: Porter, Wheat, Barleywine, Cranberry Apfelwein, Amber Ale
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