Surgical infection

• Ignaz Semmelweis, a Hungarian physician, hypothesized that puerperal fever was caused by putrid material carried on the examining fingers of medical students and physicians who cared for women dying of the disease, and who often went from the autopsy room to the wards.
• Semmelweis posted a notice on the door to the ward requiring all caregivers to rinse their hands thoroughly in chlorine water prior to entering the area, thereby reducing the mortality rate from puerperal fever on the teaching ward to 1.5%.
• Louis Pasteur, a French microbiologist, performed a body of work during the 19th century that provided the underpinnings of modern microbiology, known as “Germ Theory”.
• Pasteur elucidated the principle that contagious diseases are caused by specific microbes and that these microbes are foreign to the infected organism.
• Pasteur developed techniques of sterilization critical to oenology (study of wine and wine making) and identified several bacterias responsible for human illness, including Staphylococcus and Streptococcus pneumoniae (pneumococcus).
• Joseph Lister, the son of a wine merchant, was appointed professor of surgery at the Glasgow Royal Infirmary in 1859.
• After hearing of Pasteur’s work, Lister experimented with the use of a solution of Carbolic Acid.
• During a laparoscopic appendectomy, a large bowel injury was caused during trochar placement with spillage of bowel contents into the abdomen.
• The development of surgical site infections (SSIs) is related to three factors: degree of microbial contamination of the wound during surgery, duration of the procedure, and host factors such as diabetes, malnutrition, obesity, immune suppression.
• Inducible resistance involves mechanisms driven by natural selection over generations of antibiotic exposure, including the activation of drug efflux systems, along with other cellular mechanisms such as target site modification, changes in permeability, and drug deactivation.
• Hydrocolloid dressing is used in treatment of non-infected, mildly exuding wounds such as minor burns.
• Class III surgical wounds include open accidental wounds encountered early after injury, those with extensive introduction of bacteria into a normally sterile area of the body due to major breaks in sterile technique, gross spillage of circuit content.
• In patients with severe sepsis or septic shock, antibiotic therapy should be initiated as early as possible and within the first hour after recognition of severe sepsis/septic shock.
• Sepsis is the most common manifestation of infection, with a mortality rate exceeding 40% and is characterized by persistent hypotension requiring vasopressors to maintain MAP ≥65 and serum lactate >2 mmol/L despite adequate volume resuscitation.
• Fungi can be identified using special stains such as potassium hydroxide, India ink, methenamine silver, and Giemsa.
• Prophylaxis includes factors pertaining to skin preparation (full body bath/shower using soap, antiseptic agents, hair removal from operative site), antimicrobial therapy (perioperative antibiotics), and patient physiological management (maintenance of euglycemia, normothermia, optimization of tissue oxygenation).
• Source control involves measures undertaken to eliminate the source of infection, which generally involves drainage of all purulent material, debridement of all infected and devitalized tissue and debris, removal of foreign bodies from site of infection, and remediation of underlying cause of infection.
• Viruses are difficult to culture and require longer time typically optimal for decision making, and can be identified using host antibody response and identification of viral DNA/RNA using methods such as polymerase chain reaction.
• Septic Shock is a subset of sepsis characterized by circulatory and cellular metabolic derangements significant enough to increase risk of death.
• The microbiology of infectious agents includes bacteria, fungi, and viruses.
• The Sequential Organ Failure Assessment Score (qSOFA) is a scoring system used to assess the performance of several organ systems in the body and suggests potentially life-threatening sepsis when at least 2 of the following parameters are met: altered mental status, SBP of 100 mmHg or less, and respiratory rate of >22 breaths/minute.
• Prevention and treatment of surgical infections involve prophylaxis, which is a preventive measure taken to diminish the presence of exogenous (surgeon/operating room) and endogenous (patient) microbes.
• Appropriate use of antimicrobial agents involves prophylaxis and source control.
• Bacteria account for the majority of surgical infections and can be identified using gram stain and growth characteristics on specific media.
• Effective therapy for incisional SSIs includes incision and drainage (I/D) only without the additional use of antibiotics and antibiotic therapy is reserved for patients in whom evidence of significant cellulitis is present, or who concurrently manifest a systemic inflammatory response syndrome.
• Empiric therapy is the administration of antimicrobial agent/s when the risk of surgical infection is high.
• SSIs are classified into incisional (SSI has occurred if a surgical wound drains purulent material or if the surgeon judges it to be infected and opens it.) and organ/space infections.
• Prophylactic antibiotics are limited to the time prior to or during surgical procedure.
• Empiric therapy is based on underlying disease process or when significant contamination during surgery has occurred.
• A single dose of antibiotic is usually required.
• Prophylactic antibiotics are administered prior to surgical procedures to reduce the number of microbes in the tissue of the body cavity.
• Allergy to antimicrobial agents must be considered prior to prescribing them.
• Development of SSIs is related to three factors: degree of microbial contamination of the wound during surgery, duration of the procedure, and host factors such as diabetes, malnutrition, obesity, immune suppression; and a number of other underlying disease states.
• Penicillin Allergy is quite common, with an incidence ranging from 0.7% to 10%.
• Empiric therapy often merges with prophylaxis and is often employed on critically ill patients with identified potential sites of infection and severe sepsis or septic shock occurs.
• Misuse of antimicrobial agents is rampant in both inpatient and outpatient settings and is associated with enormous financial impact on healthcare costs, adverse reactions due to drug toxicity and allergy, occurrence of new infections such as Clostridium difficile colitis, and development of multiagent drug resistance among nosocomial pathogens.
• Surgical Site Infections (SSIs) are infections of the tissues, organs, or spaces exposed by surgeons during performance of an invasive procedure.
• Longer courses of therapy may result to superinfection by resistant organism rather than improved care.
• Agents are selected based on their activity against microbes that are likely present in the surgical room or based on knowledge of host microflora.
• Therapy for monomicrobial infections follows standard guidelines: 3-5 days for UTI, 7-8 days for pneumonia, and 7-14 days for bacteremia.