DEFINITIONIn 1992, US (CDC) revised its definition ofwound infection, creating the definition to preventconfusion between the infection of a surgicalincision and the infection of a traumaticwound(Horan et al., 1992).SSI occurs at the within of an operation or within of anoperation if a foreign body is implanted as partof the surgery.
INCIDENCE AND OUTCOME OF SSIS most frequently reported nosocomial infection. of all HAIs are SSIs. was the highest in orthopedicsurgery. , the total cost of all SSIs has beenestimated to range between
INCIDENCE AND OUTCOME OF SSIS (CONT.) Incidence is generally higher. infection rates from infection rates from after decompressive procedures. after instrumented fusions.
SOURCES OF SSIS 1. Hematogenous seeding from1. Air current deposition of a pre-existing infection at a contaminated particulates. remote site .1. Direct contact of micro- 2. Bacteria released into the organisms from contaminated wound when non-sterile body hands, instruments or sites are entered. implants. 3. Patients own skin flora .
MICROBIOLOGY OF SSIs May cause infection if the natural host is compromised eg, cutaneous coagulaseI. BACTERIA negative staphylococci. a) Gram +ve: staphylococci are the most common cause of prosthetic joint infections. b) Gram –ve: eg., pseudomonas species c) Anaerobes: eg., bacteriodes & clostridium speciesII. FUNGI
RECENT UPDATE IN MICROBIOLOGY OF SSIS“…(Dowd, Sun et al., 2008) have usedadvanced, next-generation, molecular methodssuch as bacterial Tag-Encoded FLX AmpliconPyrosequencing (bTEFAP) to evaluate themicrobial ecology of SSIs. In contrast, the results suggest thatanaerobic rod shaped bacteria predominate inbiofilms “
PATHOGENESIS OF SSIs Inoculum of the bacteria [ ] Host Determinants WoundDefenses Of MicroenvironmentIntegrity Infection Virulence of the bacterial contaminant
Bioﬁlms are surrounded by an extracellular matrix that mightphysically restrict the diffusion of antimicrobial agents.Nutrient and oxygen depletion within the bioﬁlm cause somebacteria to enter a non-growing (i.e. stationary) state in whichthey are less susceptible to growth-dependent antimicrobialkilling.
•Spreading erythema of the skin around the incision line• Local pain• Local oedema• Heat• Pyrexia• Increased exudate /suppuration• Abscess formation• Lymphangitis• Cellulitis• Loss of function of a limb• Septacaemia
Obtainfor microbiology and histology. of sinus tracts or wounds. Stop antibiotics Synovial fluid cell count – sensitivity: - Leukocytes >1,700/mm³: 94% - Neutrophils >65%: 97% as PCR.
in whom the diagnosis of prostheticjoint–associated infection has not beenestablished preoperatively. by an intraoperative frozen section tolook for evidence of acute inflammation. Varies (≥1 to ≥10 neutrophils /HPF).
Imaging plays an inferior role in early infection.Useful in delayed and late infections to assess theextent of infection.INCLUDES:
Inflammatory markers determinationis recommended but is not specific, particularly for early infection,since these parameters are high for up to two weeks after Surgery.The diagnostic accuracy for prosthetic joint infection was best for (Elie et al., 2010). levels were but had a (González et al.,2011).
RISK FACTORS & RECENT TRENDS INPREVENTION OF SSIs
RISK FACTORS OF SSIS1. Age2. Diabetes Mellitus / Perioperative Hyperglycemia3. Obesity4. Tobacco Use5. Malnutrition6. Pre-Operative Nares Colonization With Staph Aureus7. Pre-existing Remote Body Site Infection8. Compromised Immune System9. The Presence Of Cirrhosis Or Any Other Debilitating Disease10. Peri-Operative Transfusions11. Prolonged Preoperative Hospital Stay1. Operative Wound Class2. Patient Skin Preparation In The Operating Room3. Preoperative Shaving4. Perioperative Hypoxia5. Type Of Surgery6. The Duration Of Surgery7. Surgical Technique8. A Postoperative Hematoma9. Surgical drains10. Suboptimal Timing Of Antibiotic Prophylaxis11.Traffic in the Operating Room
RECENT TRENDS IN PREVENTION OF SSIsbathe as normal on the morning of surgery or the day before.Using chlorhexidine cut the risk for a SSI in half, comparedwith washing with 10% povidone-iodine.performed only when necessary via the useof electric clippers on the day of surgery.with CHG and intranasal mupirocin.wearing non-sterile theatre wear minimize therisk of SSI.
Evaluate patients for pre-existing medical conditions.Assessment of the patient’s susceptibility and risk factors forinfection.with antiseptic that contains a combination of CHGor iodine with alcohol.alcohol-based rubs is as effectiveas aqueous solutions.
Choice of antimicrobial agent:Cephalosporin (cefazolin, cefuroxime)If β lactam allergy, use clindamycin or vancomycinTiming of administration:Start up to 60 min before incision: cefazolin, cefuroxime, clindamycinStart up to 120 min before incision: vancomycinInfusion completed 10 min before tourniquet inflationDosing:Cefazolin. 1-2 g (2 g for patient weighing >86 kg)Cefuroxime, 1.5 gVancomycin and clindamycin dosing based on patient massDuration:Single preoperative doseRedose for prolonged procedure or significant blood lossdiscontinue within 24 h after wound closure
Forced air warming for patients with a bodytemperature <36°C.Using higher oxygen concentrationstriple the risk of nosocomial infection compared with no transfusion.should be maintained for the first 48 hours after surgery.By betadine, Antibiotics & DetergentsUse pulsatile lavage
laminar airflow Temperature should be maintained between (18 to 25 ºC) and humidity between (40 to 60%). a second pair of surgical gloves provides a protective barrier to both the patient and surgeon. should be resistant to tears, punctures, and abrasions.
The sterile dressing should remain in place for 24-48 hourspostoperatively.Silver-containing hydrofiber® (SCH) dressing (AQUACEL®silver [AG] dressing provides an excellent choice because:
INPATIENT SSISURVEILLANCE direct observation for SSI by a surgeon or a trained nurse combination of the following: review of microbiology reports, surgeon and/or patient surveys, and screening for readmission of surgical patients. Follow-up phone calls to patientsPOST-DISHARGE SURVEILLANCE Outpatient culture reports Outpatient reports of antibiotic usage data Readmission data to hospital or to another hospital
I. GENERAL TREATMENT OF SSIsHelps:To promote normal wound healing.Identify risk factors as obesity, DM.Identify early signs of infection.
Superficial incisional SSI can usually be treatedwithout debridement, with oral antibiotics.Suspected deep or organ/space SSI, fever(temperature>38.5◦C), or tachycardia (heart rate,110 beats/min) generally require antibiotics inaddition to opening of the suture line.Most surgical wounds that are re-opened are left toheal by secondary intention.
:Not Indicated:For uncomplicated SSIsIndicated: If there is systemic evidence ofToxicity or cellulitis that extends>2 cm beyond the incision.The Choice Of Antibiotic: Is defined by the operationperformed through the incisionand the likely infecting organism.
, the reference standard MRSA treatment. , twice as active as vancomycin against S. aureus. are recommended for theoutpatient treatment of non severe SSI. are recommended in outpatients withmoderately severe infections and for hospitalised patients withsevere SSIs. are the most active agentsagainst Gram-positive bacteria across Europe.
the germ. wound closure. spinal/vertebralstability. union of any grafts.
Extremely superﬁcial infections such as smallabscesses on the suture can be treated locally.Most superﬁcial and deep infections requireaggressive excision of tissue associated with initialintravenous antibiotic therapy.The duration of initial parenteral antibiotictreatment is usually 15 days. Then propose oralantibiotics.Some recommend removing all bone graft and spinalimplants, whereas others support leaving well-fixedposterior instrumentation (particularly titanium) and bonegrafts in place, even in the face of active infection.
If the implant is stable, debridement with retention of the device combined with long-term antibiotic treatment. If resistant or difficult-to-treat microorganisms are causing the infection complete hardware removal and external fixation is preferable. Duration is 3 months in cases of device retention and 6 weeks after removal of the infected fixation device. IV treatment should be administered for the first 2−4 wks, followed by oral therapy.