Final answer:
a) Yes, it's probable due to IVDU
The patient with an abscess and a history of intravenous drug use should be covered for MRSA due to the elevated risk associated with IVDU and potential comorbidities like diabetes that can exacerbate infections.
Step-by-step explanation:
In this case, the patient presents with an abscess on his foot and admits to being an occasional intravenous drug user (IVDU), with injection marks visible on his arm. Given the scenario, it would be prudent to cover for MRSA when treating the abscess. MRSA, or Methicillin-resistant Staphylococcus aureus, is a common cause of skin and soft tissue infections, particularly in individuals with a history of IVDU. Moreover, MRSA can lead to more severe or invasive infections if not addressed properly. There is a known association between IVDU and an increased risk of contracting MRSA infections due to factors such as shared needles, non-sterile injection practices, and possible compromised immunity in drug users. Additionally, MRSA can be particularly troublesome in individuals with certain comorbidity like diabetes, as diabetic patients tend to have more complications from infections in general.