Surgical site infections (SSIs) are a common complication following surgical procedures. These infections occur in the area where surgery took place, affecting the skin incision or deeper tissues and organs. They can develop within 30 days of the operation, or up to one year if an implant was involved. Understanding the microorganisms responsible is key to prevention.
Identifying the Primary Culprit
The bacterium most frequently identified as the cause of surgical site infections is Staphylococcus aureus. This microorganism is commonly found in healthcare settings, on human skin, and in nasal passages of healthy individuals.
Staphylococcus aureus can be introduced to the surgical site from the patient’s own body, contaminated surgical instruments, or healthcare providers. Its widespread presence and easy transfer contribute to its involvement in post-surgical infections. While the specific type of surgery can influence isolated pathogens, Staphylococcus aureus consistently ranks high.
Characteristics Contributing to Its Prevalence
Staphylococcus aureus’s prevalence in surgical site infections stems from several inherent characteristics. It is a normal inhabitant of human skin and mucous membranes, colonizing individuals without causing harm, yet remaining a potential source of infection during surgery. This allows the bacteria to be readily present on a patient’s body.
Staphylococcus aureus also demonstrates an ability to survive on inanimate surfaces within hospital environments. This environmental persistence facilitates its spread and potential contamination of surgical sites. A concern is the increasing incidence of antibiotic resistance in Staphylococcus aureus strains, particularly Methicillin-resistant Staphylococcus aureus (MRSA), which complicates treatment and prolongs patient recovery. These factors contribute to its high incidence in surgical wound infections.
Other Significant Microorganisms
While Staphylococcus aureus is the most common cause, other microorganisms also contribute to surgical site infections. Coagulase-negative staphylococci (CoNS) are frequently isolated, often originating from the patient’s own skin flora, similar to Staphylococcus aureus. These bacteria can colonize medical devices, leading to infections, especially in procedures involving implants.
Pseudomonas aeruginosa is another bacterium that can cause SSIs, particularly in wet environments or in patients with compromised immune systems. These infections can be more challenging to treat due to Pseudomonas aeruginosa’s inherent antibiotic resistance. Enterococcus species, commonly found in the human gut, can also be implicated in SSIs, especially following abdominal surgeries where bowel contents may contaminate the surgical field. These bacteria, along with certain Gram-negative bacilli, highlight the diverse microbial landscape that can lead to post-surgical complications, though they are less frequently encountered than Staphylococcus aureus.