Are there certain people that are more susceptible to sepsis?

Yes: We don't know all the factors that predispose people to sepsis syndrome or septic shock, but older (age >65), malnourished, immune compromised (but with some immune system in place) , diabetic patients, and possibly morbidly obese patients are more at risk.

Yes: More complex the medical issues like diabetes, immunodef or chronic illnesses- , more likely the chance of infection and for it to progress to sepsis. Certain genetic factors are also being implicated. Also life style issues like smoking, etoh or drugs use make one more liable to have sepsis, and be sick longer with it..