How many days a bacterial infection strikes depends on its incubation period. The incubation period of bacterial infections varies from as short as half an hour to months and years. There are many types of bacteria and the incubation period varies. For example, the incubation period of tetanus bacillus is usually about one week, and there are patients who develop the disease within 24 hours after infection, but the incubation period of individual patients can be as long as several months or even years. Generally speaking, the shorter the incubation period, the more serious the symptoms of tetanus infection. Another example is that the incubation period of Streptococcus pneumoniae is usually around 7 days, B. pertussis is around 10 days, the incubation period of food poisoning caused by Salmonella is 8 to 48 hours, and the incubation period of food poisoning caused by Aspergillus is only half an hour to 2 hours. To summarize, the incubation period of different germs is not the same at the same time. Due to individual differences, the body’s resistance is different, which also affects the incubation period of bacteria.