Targeting virulence factors, produced by bacteria to evade the immune system, is another approach to find new anti-infectives medications. In this light, Shapiro and Wencewicz investigated the virulence factor acinetobactin and its precursor produced by Acinetobacter Baumanii.

The precursor of acinetobactin, creatively called pre- acinetobactin, seems to be most stable in acidic environments, such as wounds. The protein serves to sequester iron from its surroundings, which is essential for the bacterium to survive. As a wound has limited size, bacteria, in their expansion urge, need to move deeper into the tissue and into the blood stream. The blood stream is much more alkaline than  a wound, say pH 7.4 versus pH 5 (remember that pH reflects the negative logarithm of the H+ concentration ;), i.e. a difference of two units reflects a 100-fold difference in H+ concentration). Interestingly enough, this precursor virulence factor is less stable in alkaline environments, leading to its conversion to acinetobactin, which is stable in a more alkaline environment, hence providing the expanding bacteria with an increased access to iron in the blood, ensuring their survival..