Surgical Infections

SURGICAL INFECTIONS Gastrointestinal surgical department of affiliated hospital of jining medical college

SURGICAL INFECTIONS 

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Infections that require surgical treatment or related to operative interventions

SURGICAL INFECTIONS 

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Infections required surgical treatment • Necrotizing soft tissue infections • Infections of body cavities (peritonitis, empyema, etc.) • Infections confined to an organ or tissue (abscesses, septic arthritis, cholecystitis, etc) • Prosthetic device infections

SURGICAL INFECTIONS INFECTIONS RELATED TO OPERATIVE INTERVENTION  • Wound infections - Surgical site infections  • Postoperative infections (peritonitis or other cavity infections)  • Surgical nosocomial infections (pneumonia, urinary tract infections, catheter infections) 

NOSOCOMIAL INFECTIONS 

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Occurs after the initial 48 hours of admission • Urinary tract infection • (IV) Catheter-related infection • Lower respiratory tract infection • Infection via transfusion

PATHOGENESIS 

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DETERMINANTS OF INFECTIONS Microorganism Host Defenses (virulance) (type&severity of immunosupression) INFECTION Environment (Fluids, foreign bodies, a closed unperfused space etc.)

Infectious agent 

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The Endogenous Gastrointestinal Microflora • Stomach • Duodenum Aerobes and anaerobes • Proximal small bowel <104/mL • Distal small bowel Enterobacteriaceae Enterococcus spp 103-108/mL Anaerobic organisms • Colon Anaerobic organisms Bacteriodes fragilis 1012/mL

Microbiology of Intraabdominal Infections            

Aerobes: Escerichia coli Klebsiella spp. Proteus spp Enterobacter spp Enterococcus spp Anaerobes: Bacteriodes spp Peptostreptococcus spp Clostridium spp Bilophila wadsworthia Fungi,Candida

HOST DEFENSE MECHANISMS   

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Nonspecific Surface Mechanical barrier (skin, mucosa) Secretory barrier Immunoglobulins Ciliary motion Movement

HOST MECHANISMS  

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DEFENSE

Specific Cellular defense Phagocytic cells Cell-mediated immunity (PNLs, eosinophils, mononuclear cells) (T lymphocytes & macrophages) Natural killer cells Humoral defense Lyzozyme Immunoglobulins Complement Interferon

A Susceptible host             

Causes of Impaired Host Resistance to Infection Patient’s Underlying Condition • AIDS • Remote infection • Neoplasia • Malnutrition • Acute stress (burns, trauma) • Metabolic illness (DM, uremia) • Aging • Obesity • Smoking

A Susceptible host        

Iatrogenic • Antineoplastic chemotherapy • Immunosuppressive therapy (allograft recipients, autoimmune disorders) • Splenectomy

Infection Environment 

Wound or a natural space with narrow outlets

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Fluids, foreign bodies, a closed unperfused space etc

Clinical finding LOCAL MANIFESTATIONS OF SURGICAL INFECTIONS  • CELLULITIS: Spreading infection of the skin and subcutaneous tissue  • LYMPHANGITIS: Inflammation of the lymphatic channels in the subcutaneous tissue  • ABSCESS: Localized accumulation of purulent material situated in the dermis or subcutaneous tissue 

SURGICAL SITE INFECTION The term “surgical site infection” now replaces “surgical wound infection”  • Superficial incisional SSI; involves the skin or subcutaneous tissue  • Deep incisional SSI; involves the deep tissue such as fascia or muscle,Organ/space SSI 

SURGICAL SITE INFECTION DEFINITION  

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Superficial Incisional Infection Any incisional infection occuring within postoperative 30 days at any level above fascia described as; • Presence of any purulant discharge (culture may not reveal any opponent) • Any positive culture findings from primarily closed incision • Deleberate incision exploration • Infection diagnosis determined by the surgeon

SURGICAL SITE INFECTION DEFINITION  

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Deep Incisional /Organ / Space Infection Any infection occuring within postoperative 30 days or within postoperative one year if any implant is left described as; • Presence of any purulant discharge (through drains) • Any positive culture findings from intraabdominal samples • Spontaneous wound dehiscence • Presence of abscess • Infection diagnosis determined by the surgeon

Diagnosis     

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Redness Swelling Hyperthermia Fluctuation Purulent or turbid aspirate

OPERATIVE WOUNDS 

NATIONAL RESEARCH COUNCIL CLASSIFICATION OF OPERATIVE WOUNDS

CLASSIFICATION OF OPERATIVE WOUNDS     

CLEAN • Nontraumatic • No inflammation encountered • No break in technique • Respiratory, alimentary, genitourinary tracts not entered

CLASSIFICATION OF OPERATIVE WOUNDS  

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CLEAN CONTAMINATED • Gastrointestinal or respiratory tracts entered without significant spillage • Appendectomy • Oropharynx entered • Vagina entered • Genitourinary tract entered in absence of infected urine • Biliary tract entered in absence of infected bile • Minor break in technique

CLASSIFICATION OF OPERATIVE WOUNDS   

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CONTAMINATED • Major break in technique • Gross spillage from gastrointestinal tract • Traumatic wound, fresh • Entrance of genitourinary or biliary tracts in presence of infected urine or bile

CLASSIFICATION OF OPERATIVE WOUNDS  

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DIRTY and INFECTED • Acute bacterial inflammation encountered, without pus • Transection of clean tissue for the purpose of surgical access to a collection of pus • Traumatic wound with retained devitalized tissue,foreign bodies, fecal contamination, and/or delayed treatment, or from dirty source.

Treatment    

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Principles of Antibiotic Therapy • Why to use antibiotics? • Where is infection? • What are the most probable pathogens? • How about antibiotic susceptibility? • Pharmacological properties • Is combination of antibiotics necessary? • Host factors • Monitoring accuracy of therapy