Harr Microbiology Practice Test 2025 - Free Microbiology Practice Questions and Study Guide

In the context of the interpretation of isolated β-hemolytic streptococci from a urinary tract specimen, recognizing Enterococcus faecalis as the correct interpretation stems from its biochemical characteristics and clinical significance.

Enterococcus faecalis is a member of the group of bacteria that are known to exhibit β-hemolysis on blood agar, although it is not classified as either Group A (Streptococcus pyogenes) or Group B (Streptococcus agalactiae). Enterococci are often part of normal gastrointestinal flora but can also be opportunistic pathogens, particularly in urinary tract infections, demonstrating a noteworthy ability to thrive in such environments.

In urinary tract infections, the presence of β-hemolytic enterococci, particularly Enterococcus faecalis, can indicate a potential pathogen rather than a commensal organism, especially if they are isolated from a symptomatic patient. This distinction is important for both diagnosis and treatment since Enterococcus faecalis can often be resistant to many common antibiotics.

The reference to Group A and Group B streptococci involves distinct pathogens with specific clinical implications. Group A is more commonly associated with throat infections, skin infections, and conditions like rheumatic fever, whereas Group B