Patient is healthy but has severe stressor or patient is chronically or severely ill with ego deficits .
健康但有严重应激或者自我缺乏的重病人或慢性病人。
One possibility is that the bacteria were not actually responding to the presence of neighboring colonies , but were simply producing biofilm because ammonia raised the ph of the bacteria 's surroundings-an environmental stressor that could encourage slimy growth .