Clinical Laboratory Perspective on Streptococcus halichoeri, an Unusual Nonhemolytic, Lancefield Group B...

Area of Science:

• Microbiology
• Infectious Diseases
• Zoonoses

Background:

• Streptococcus halichoeri is a recently identified pyogenic streptococcus species.
• This bacterium, originally found in seals, can cause zoonotic infections in humans.
• Human infections are rare, with only eight cases reported previously.

Purpose of the Study:

• To report three cases of Streptococcus halichoeri bone and joint infections in US patients.
• To examine the microbiological characteristics of S. halichoeri.
• To highlight the importance of accurate identification of S. halichoeri.

Main Methods:

• Case series of three patients with S. halichoeri bone and joint infections.
• Microbiological analysis of S. halichoeri isolates.
• Identification methods including matrix-assisted laser desorption/ionization time of flight mass spectrometry and 16S rRNA sequencing were considered.

Main Results:

• Three cases of S. halichoeri bone and joint infections were identified in patients with underlying health conditions.
• S. halichoeri can exhibit catalase positivity and appear as nonhemolytic colonies, potentially leading to misidentification.
• The organism shares Lancefield group B antigen with Streptococcus agalactiae.

Conclusions:

• Streptococcus halichoeri can cause significant bone and joint infections in humans.
• Misidentification is a risk due to its phenotypic characteristics.
• Accurate identification using advanced techniques is essential for appropriate patient management.