What is the correct identification for a catalase-negative, gram-positive coccus resembling staphylococci isolated from blood cultures of a patient with endocarditis?

The correct identification for a catalase-negative, gram-positive coccus resembling staphylococci isolated from blood cultures of a patient with endocarditis is Enterococcus spp.

Enterococcus species, particularly Enterococcus faecalis and Enterococcus faecium, are well-known pathogens that can be associated with endocarditis and are frequently isolated from blood cultures. They are characterized by their spherical shape and can appear in pairs or short chains, resembling staphylococci due to their coccus shape, but they are catalase-negative, which distinguishes them from staphylococci that are typically catalase-positive.

In the context provided, the individual in question has developed endocarditis, which often results from the presence of Enterococci, especially in patients with underlying health issues or following procedures that could introduce these bacteria into the bloodstream. Their ability to survive in harsh conditions and resistance to many antibiotics make them significant in clinical microbiology.

Leuconostoc and Micrococcus species are less commonly associated with severe infections such as endocarditis, and Genella is a less recognized pathogen in comparison to Enterococcus in this clinical scenario. Consequently, Enterococcus spp. stands out as the most appropriate identification given this context.