What are wound infections?

Definition

Wound infections involve injury marked by the division of tissue or the rupture of membranes. These injuries develop infections caused by bacteria, viruses, or fungi. For surgical cases, wound infections are specific to the surgical site.

Introduction

Wounds caused by trauma or obtained during surgical procedures (invasive and noninvasive surgery) can become breeding grounds for infections. The majority of wound infections are caused by bacteria such as staphylococci and streptococci. Many surgical infections are caused by Staphylococcus aureus or S. epidermis. Symptoms of wound infection include pain, swelling, and redness, and drainage from the wound area. An accompanying fever means the infection has spread through the body.

Specific types of wounds are more likely to be susceptible to tetanus
(Clostridium tetani) infection, including puncture wounds,
burns, and frostbite. Tetanus results from bacteria spores present in soil. These
spores invade the wound, resulting in neurologic conditions, particularly spasms,
and fever. Gas gangrene is a tissue-destroying infection caused by
Clostridium species and can result in septic
shock.

Types of wound infection of special concern are methicillin-resistant
S. aureus (MRSA) infection and vancomycin-resistant
Enterococcus (VRE) infection, which are prevalent in hospitals
and are resistant to treatment with antibiotics. Hospitalized persons are
especially susceptible because they may already have a compromised
immune
system and are sometimes exposed to germs from other sick
patients. MRSA and VRE are common in community spaces, especially day-care
centers, dormitories, and athletic facilities. Skin
infections can occur in a rash or wound. Wounds exposed to
fresh water or sea water are often susceptible to waterborne organisms such as
Aeromonas, Pseudomonas, and Vibrio
vulnificus.

Risk Factors

Some studies have demonstrated that certain characteristics render persons more
susceptible to wound infections, compared with persons who do not have these
factors. Obesity and diabetes have high wound infection rates. Specific
surgical-infection risk factors include diabetes, obesity, the
receipt of a blood transfusion during surgery, older age,
hypertension, hyperlipidemia, length of surgery, and
smoking.

Prevention

Tetanus infection is completely preventable with vaccine, which is effective
for ten to twelve years. MRSA, VRE, and other infections occurring commonly in
clinics and hospitals can be reduced by practicing universal precautions, which
are instrumental in preventing infection when treating the wounded. Universal
precautions involve treating biologic fluids as though they were infected with the
human
immunodeficiency virus or another pathogen, treating each
patient cautiously to avoid exposing oneself and others, thorough handwashing,
sterilizing instruments, wearing protective gear, and properly disposing of
medical waste.

Instrument sterilization, however, can be less effective than one might think. At any step of the sterilization process, it is possible to reintroduce bacteria. Some hospitals are opting to use new, unused instruments for each surgery. Debate continues about whether wearing face masks during surgery protects patients; however, it does protect medical staff from blood spatter to the face. Prophylactic antibiotics before, during, and after surgery are often helpful in reducing infection rate, such as for knee or hip replacement.

Treatment

Depending on the type of infection, a lack of treatment may result in blood
poisoning, gangrene (tissue death), or death. According to the
World Health
Organization, one should never close up an infected wound. A
protocol of washing, debridement (removing any dirt and dead tissue), and saline
irrigation should be followed and the wound should be left open but covered with
dressing; the dressing should be changed a minimum of once per day. If the wound
is not open but it does have pus under the surface, it is critical to drain the
subcutaneous pus. Intravenous antibiotics should be used to treat bacterial
infection, preferably tailored to the type of infection (if
testing is available at the site) to reduce unnecessary overexposure to
antibiotics.

Impact

Infected wounds affect millions worldwide and can result in debilitation or death. Appropriate preventive measures and effective treatments are essential in reducing the widespread effects of wound infection.

Bibliography

Al-Buhairan, B., D. Hind, and A. Hutchinson. “Antibiotic Prophylaxis for Wound Infections in Total Joint Arthroplasty.” Journal of Bone and Joint Surgery 90-B (2007): 915-919. A review of the evidence from twenty-six studies, reporting on the effectiveness of prophylactic antibiotics in reducing infections in persons having total knee or total hip replacement.

Downie, Fiona, et al. “Barrier Dressings in Surgical Site Infection Prevention Strategies.” British Journal of Nursing 19 (2010): S42-S46. This clinical article provides a multifaceted model for preventing surgical infections. Focuses largely on vapor-permeable dressings postsurgery.

Matros, Evan, et al. “Reduction in Incidence of Deep Sternal Wound Infections: Random or Real?” Journal of Thoracic and Cardiovascular Surgery 139 (2010): 680-685. Analyzes trends in the risk factors associated with deep sternal wound infections.

Olsen, Margaret A., et al. “Risk Factors for Surgical Site Infection Following Orthopaedic Spinal Operations.” Journal of Bone and Joint Surgery 90 (2008): 62-69. Discusses a retrospective, case-control study of risk factors associated with spinal surgery.

Perry, Christine, ed. Infection Prevention and Control. Malden, Mass.: Blackwell, 2007. An evidence-based guide that describes in detail areas such as urinary catheter care, pediatric care, and wound prevention and management.