An infection preventionist is preparing an in-service for a new program on total joint replacement.

The Certification Study Guide (6th edition) identifies coagulase-negative staphylococci (CoNS) as among the most common causes of surgical site infections following orthopedic implant procedures, including total hip replacement. These organisms are part of normal human skin flora and are therefore a frequent source of contamination during surgery, even when aseptic technique is followed. Their importance is heightened in procedures involving prosthetic material because CoNS have a strong ability to adhere to foreign bodies and form biofilms, which protect bacteria from host defenses and antimicrobial therapy.

The study guide emphasizes that SSIs following joint replacement procedures often present within 30 to 60 days postoperatively and are typically caused by gram-positive cocci, particularly Staphylococcus aureus and coagulase-negative staphylococci. CoNS are especially associated with indolent or delayed infections involving implanted devices, making them a critical teaching point in joint replacement programs.

The other organisms listed are less likely causes in this setting. Escherichia coli and Pseudomonas aeruginosa are more commonly associated with gastrointestinal, urinary, or moist environmental sources rather than clean orthopedic procedures. Group A streptococci may cause acute SSIs but are far less common in prosthetic joint infections.

Understanding organism-specific risks allows infection preventionists to target prevention strategies, antimicrobial prophylaxis, and surveillance effectively—key competencies tested on the CIC exam.