A patient with >100,000 col/mL of a nonhemolytic, catalase-negative organism in urine culture is likely infected by which organism?

The presence of a nonhemolytic, catalase-negative organism in a urine culture with a concentration of more than 100,000 col/mL suggests the presence of Enterococcus faecalis. This organism is known to cause urinary tract infections (UTIs), particularly in cases where other more common pathogens are not the causative factors.

Enterococcus faecalis is a Gram-positive cocci that is typically catalase-negative, which aligns with the characteristics described in the question. It can often present in significant quantities in urine cultures, particularly in patients with risk factors such as prolonged catheterization or underlying health conditions.

In contrast, the other options are either hemolytic or have different cultural properties that would not match the scenario presented. Streptococcus pyogenes, for example, is a beta-hemolytic bacterium, which would not be categorized as nonhemolytic. Streptococcus agalactiae is also a beta-hemolytic organism but is primarily associated with infections in neonates and pregnant women. Similarly, Streptococcus bovis is generally not considered a common urinary pathogen. Thus, Enterococcus faecalis stands out as the likely organism in this scenario.