Recurring Salmonella Infections can be the bane of a person’s life. Despite antibiotic therapy the infection stubbornly reoccurs without little in the way of an answer why – until now. Researchers may have just found an important aspect of the answer by discovering a bacterial ‘alarm clock’ common to different types of bacteria including members of the genus Salmonella. The alarm clock mechanism appears to cause bacterial reactivation once the threat posed by the body’s immune system has waned.
By ceasing replication the bacteria can remain in a latent state for days, weeks or months but capable of reactivation once the immune system has stopped its attack. Bacteria displaying this property have been referred to as persisters. This reactivation process is suspected to cause the recurrence of the infection. It’s thought a third of salmonellae hide themselves in this manner. An additional issue may be emergence of antibiotic resistant bacteria due to bacteria surviving a course of antibiotics, remerging to an infectious state and being exposed to a secondary course of antibiotics.
The study suggests that the salmonellae induce this hiding mode by ‘poisoning’ themselves with toxins, for example the so-called TacT toxin which blocks translation during protein synthesis. Once the threat has passed the salmonellae then use a detoxifying mechanism involving peptidyl-tRNA hydrolase (Pth) to neutralise TacT.
This research sheds light on a bacterial mechanism with the potential to contribute to antibiotic resistance. On the other hand, the study may be the start of understanding the microbial biochemistry involved in such a way that gives rise to new options in preventing antibiotic resistance.