Final answer:
The presence of Corynebacterium spp. in a blood culture from a 76-year-old man suggests an infection with this opportunistic pathogen, which can cause various illnesses including respiratory infections and requires species-specific identification and treatment.
Step-by-step explanation:
The question concerns a 76-year-old man with intermittent fevers, who has had blood cultures drawn. One of the cultures grew Corynebacterium spp., which is a genus of bacteria that can be classified as either an opportunistic pathogen or a nonpathogen, depending on the species and the immune status of the patient. In a clinical context, the presence of Corynebacterium in a blood culture is significant and generally warrants treatment, especially in an elderly patient who may have a compromised immune system.
Corynebacterium spp. are pleomorphic, meaning they can appear in various shapes, including as coccobacilli, and they are aerobes or facultative anaerobes that grow on blood agar. While some species in this genus are nonpathogenic, others can cause a range of infections, including respiratory infections. It is essential to identify the exact species, as this will dictate the treatment plan. For instance, Corynebacterium diphtheriae is a pathogenic species that causes diphtheria, whereas other species might be less virulent.