Microenvironment Of The Wound Essay

may enter the wound from the air in the OR(operating room), or from the instruments or surgeon(s) that come into contact with the wound. Skin bacteria are1 always present despite the throughness of the preparation of the skin. The largest inoculums of bacteria at the surgical site occur when the operation involves a body structure that ordinarily is heavily colonized by bacteria, such as the bowel. Procedures involving the female genital tract will encounter 106 – 107 bacterial/ml. 29
Virulence of the Bacterial Contaminant
A second determinant contributing to SSIs is the virulence of the bacterial contaminant. The more virulent the bacterial contaminant, the greater the probability of infection. Coagulase-positive staphylococci require smaller inoculums than the coagulase-negative species. Uncommon but virulent strains of clostridium perfringens or group A streptococci require a small inoculums to cause
Hemoglobin at the surgical site is a well known adjuvant substance. It is generally thought that the release of ferric iron during the degradation of red blood cells stimulates microbial proliferation. Necrotic tissue can act as a heaven for contaminants to avoid phagocytic defenses of the host. Foreign bodies, particularly braided silk and other permanent braided suture materials, similarly harbor microbes and increase the probability of infection. Dead space within the surgical site also provides a local environment that fosters infection.29
The Integrity of Host Defenses
The fourth determinant of wound infection is the integrity of host defenses. Impaired host defenses can be viewed as innate or acquired. Innate impairment refers to the observation that intrinsic responses in some patients are less effective than in others. Variability is regularly found among all patients in various components of