Wound infection may occur after any kind of skin trauma that causes significant disruption of the skin and bacterial pathogens such as Staphylococcus sp. are the most common causes. Localized pain, edema and erythema are main symptoms. The diagnosis can be made during physical examination and wound swabs are needed to confirm the underlying cause. Treatment involves antibiotics and debridement.
Depending on the type of wound infection and its location, numerous signs and symptoms may be seen, but localized pain, erythema, increased temperature, edema, malodour, wound deterioration and breakdown are common clinical findings  . Either purulent or serous exudates may be observed as well, whereas systemic symptoms (fever, chills) indicate bacterial spread, which mandates an immediate diagnostic workup and initiation of empiric therapy .
Entire Body System
Fever. A fever occurs. The wound hasn't healed within 10 days after the injury. [seattlechildrens.org]
Diagnosis is made by the clinical presentation of fever, chest pain, or sternal instability in the setting of wound drainage, positive wound cultures, or chest radiographic findings. [ncbi.nlm.nih.gov]
[…] contact your maternity care provider if you think you may have a wound infection or have the following symptoms or concerns: • Discharge or liquid coming out of incision • Incision that is opening up • Redness or swelling • Pain that is getting worse • Fever [bcwomens.ca]
Fever and pain relief Give your child acetaminophen or ibuprofen if he develops a fever over 102 F (39 C) or the wound is painful. Contagiousness The pus from wound infections is somewhat contagious. [summitmedicalgroup.com]
For suppurative appendicitis and gangrenous or perforated cases wound infection rates were 9.1% versus 17.6% for open appendectomy versus laparoscopy. [ncbi.nlm.nih.gov]
Foster’s brother, a confederate soldier, has ‘hospital gangrene’, but hopes to avoid amputation. Dr. Foster is faced with a difficult decision. Fearing the contagiousness of ‘hospital gangrene’, Dr. [pbs.org]
Gangrene is caused by a lack of blood flow to a certain part of the body, and so diabetes can cause "dry" gangrene by destroying blood vessels. [diabetes.co.uk]
The latter infections are rare but very serious and include gas gangrene and so-called flesh-eating infections (known medically as necrotizing faciitis ). [livestrong.com]
[…] from spreading to your entire body and jeopardizing your life: Circulation decreases; the extremity feels cool/cold Wound or area smells bad Swollen glands in groin or armpits Wound has thick, brown/gray discharge Skin around the wound turns black or gangrenous [amputee-coalition.org]
Feelings of Malaise Malaise is a common non-specific sign of a localized systemic infection. It is a feeling of tiredness and a lack of energy. You may not feel up to completing normal activities or begin sleeping more than usual. [advancedtissue.com]
In these cases, diagnosis may rely on non-specific symptoms such as loss of appetite, malaise, or decrease in glycemic control in diabetics. [woundsource.com]
There were 1 patient with paralytic scoliosis and 4 with cerebral palsy. All wound healed completely within 5.2 1.8 weeks of MDT or 8.8 3.8 cycles of MDT. There was no recurrence on final follow-up of 21.6 5.9 months. [ncbi.nlm.nih.gov]
Delayed Wound Healing
Abstract Bacterial biofilm which adheres onto wound surface is shown to be impervious to antibiotics and this in turn delays wound healing. [ncbi.nlm.nih.gov]
High dose infection and persistence were also associated with immune cell infiltration, despite suppression of some inflammatory cytokines and delayed wound healing. [biorxiv.org]
However, despite the evidence for the presence of biofilm in wounds, research studies are required to detect biofilm and to determine the exact role played by multispecies biofilms in terms of delayed wound-healing process [ 26 ]. [intechopen.com]
Cochrane Database of Systematic Reviews Background Surgical site infections (SSI) can delay wound healing, impair cosmetic outcome and increase healthcare costs. [cochranelibrary.com]
The diagnosis can be made relatively easy by observing typical signs of wound infection during physical examination. To determine optimal therapy, however, it is necessary to identify the underlying pathogen and superficial wound swabs with subsequent cultivation of the samples is performed in most cases . In patients with suspected sepsis, blood cultures may be a good source as well. Once the cause is confirmed, antimicrobial susceptibility testing is mandated in order to assess the presence potential antimicrobial resistant, which has become a major problem in medical practice in recent years.
For localized uncomplicated infections, debridement of the wound with appropriate antimicrobial therapy based on antimicrobial susceptibility testing. Current guidelines suggest trimethoprim-sulfamethoxazole (TMP-SMX) or clindamycin as first-line empiric therapy in milder forms, whereas piperacillin-tazobactam, doripenem, imipenem, meropenem, ertapenem and vancomycin are used in severe infections that necessitate hospitalization and adequate supportive care . When highly resistant organisms are suspected, linezolid, daptomycin, telavancin and ceftaroline may be used before the results of antimicrobial susceptibility tests arrive .
Most common causes of wound infection are  :
- Methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA)
- Staphylococcus epidermidis
- Pseudomonas aeruginosa
- Enterococcus faecalis
- Escherichia coli
- Clostridium perfringens
- Clostridium tetany
It must be mentioned that it is not uncommon for wound infection to be polymicrobial, i.e. more than one pathogen may colonize the wound and establish an infection .
Numerous factors have shown to play a role in the development of wound infection   :
- Wound features - Depth and location of the wound, as well as level of tissue perfusion.
- Mode of wound acquisition - Wounds may be a result of accidental trauma or due to hospital-related procedures and events. Use of intravenous devices, pressure sores (decubitus ulcers), but most commonly, surgical procedures are the predisposing event . Moreover, a significantly increased risk was observed during surgeries that predispose to endogenous contamination (such as GI surgery) compared to superficial clean procedures (27% vs 1-5%, respectively). Overall rates of wound infection from surgical procedures ranges from 1.5% to 52%, depending on the type of surgery and level of its invasiveness.
- Host factors - Presence of comorbidities or diseases that impair immune function (eg. diabetes mellitus, human immunodeficiency virus or HIV infection, use of corticosteroid therapy) can markedly increase the risk of wound infection.
Development of an infection on the site of the wound is a complex process involving several phases, but the principal event is disrupted integrity of the skin, allowing colonization of subcutaneous and soft tissues by microbial organisms. The degree of contamination and wound depth, but also the status of the immune system, determines the clinical presentation and the severity of symptoms .
Physical disruption of the normal skin may occur due to various forms of trauma (either accidental or hospital-induced - during surgical procedures, use of intravenous medical devices, pressure sores, etc) and can all predispose to infection of the wound by various microbial organisms . Most frequent pathogens are Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus epidermidis, Escherichia coli and Enterococcus faecalis , but a myriad of bacterial organisms have been identified as potential causes. Several factors increase the risk of wound infection and its severity. Older age, repeated trauma, presence of an immunosuppressed disease and other comorbidities that impair normal wound healing , while characteristics of the wound (type, location, level of tissue perfusion and depth) are also notable factors . Wound infections may be either acute or chronic and can involve the skin or underlying soft tissues, giving symptoms such as pain, local erythema, edema, presence of pus or serous exudate, together with a foul odor and discoloration of granulation tissue . The diagnosis is made during physical examination and the source of trauma is determined through adequate patient history. Antibiotics and surgical debridement, when necessary, is used in therapy . The prognosis is good with early and appropriate treatment, but severe tissue destruction and an increased risk for severe forms of infection (sepsis) may occur if the condition is not recognized on time.
Various forms of trauma - accidents, animal bites and in-hospital procedures that cause damage to the skin and underlying tissues, can predispose individuals to an infection of the wound that was produced as a result of that trauma. Under physiological conditions, the main role of the skin is to serve as a barrier for microorganisms, but if there is a breach in the skin, the bacteria may enter the tissue and establish an infection. Notable risk factors for wound infection are older age, an immunosuppressed status, presence of comorbidities that impair normal wound healing (eg. diabetes mellitus, use of corticosteroids) and increased depth of the wound. If a wound is infected by bacteria (most commonly by Staphylococcus aureus), local redness, pain and heat, a foul odor from the wound and presence of pus are most common symptoms. The diagnosis is made during physical examination and a swab from the wound is obtained to determine which bacteria caused the infection. Debridement of the wound and antibiotics are used with great efficacy, but the diagnosis must be made early on, as dissemination of bacteria from the wound into the circulation can cause life-threatening sepsis. For this reason, great attention to wound care is necessary to reduce the risk of bacterial colonization.
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- European Wound Management Association. Position Document: Identifying criteria for wound infection. London: MEP Ltd, 2005.