Antibiotic-resistant Staphylococcus epidermidis in patients undergoing cardiac surgery

Area of Science:

• Clinical Microbiology
• Infectious Diseases
• Surgical Site Infections

Background:

• Staphylococcus epidermidis is a common cause of healthcare-associated infections.
• Antibiotic resistance in S. epidermidis is a growing concern, particularly in surgical patients.
• Methicillin resistance in S. epidermidis (MRSE) can complicate treatment and increase morbidity.

Purpose of the Study:

• To investigate the prevalence and antibiotic resistance patterns of Staphylococcus epidermidis colonization in patients before and after cardiac surgery.
• To determine the risk factors associated with the development of methicillin-resistant S. epidermidis (MRSE) postoperatively.
• To assess the potential for MRSE to cause serious infections, such as prosthetic valve endocarditis.

Main Methods:

• Prospective study involving 80 patients undergoing cardiac surgery.
• Collection of S. epidermidis isolates from patient chests preoperatively and from surgical wounds postoperatively.
• Antimicrobial susceptibility testing of all isolates against various antibiotics, including methicillin.

Main Results:

• Preoperative MRSE colonization was low (4%), increasing significantly to 54% by 5 days postoperatively.
• Postoperative MRSE isolates demonstrated high resistance rates to multiple antibiotics, including nafcillin (100%), penicillin (100%), cephalothin (93%), and cefamandole (80%).
• Two patients developed S. epidermidis prosthetic valve endocarditis caused by multidrug-resistant isolates with identical susceptibility patterns to their postoperative chest isolates.

Conclusions:

• Cardiac surgery is associated with a substantial increase in MRSE colonization.
• Postoperative MRSE strains are frequently multidrug-resistant, necessitating careful antibiotic stewardship.
• The findings highlight the importance of infection control measures to prevent MRSE transmission and subsequent infections in surgical settings.