A microbiologist has isolated a bacterium from his face and wishes to determine whether it might be a member of the normal microbiota. Which of the following would NOT be evidence for such a conclusion? The bacterium is extremely salt tolerant. The bacterium is an acidophile. The bacterium is resistant to antibodies. The bacterium produces a number of virulence factors.

The skin is inhabited by a heterogeneous group of bacteria, fungi and viruses, all of them form the skin microbiota. The skin surface varies among our bodies sites but has two main characteristics: is highly salty and acidic. For this reason, bacteria that live in our skin is salt resistant and acidophile (can survive in acidic conditions), also skin microbiota bacteria must be resistant to the host immune system (antibodies) if not, the immune system kills the bacteria.

The term virulence factor refers to the abilities that have the bacteria to enter the host, persist, and initiate an infection. All the potentially harmful bacteria carry virulence factors and these bacteria can be found in diverse environments, for this reason, this is not evidence to be part of the skin microbiota.