1. Joseph Castellano M.D. 9/29/09
Surgical Infections
Joseph Castellano M.D.
9/29/09

2. Definition
Infections that require surgical intervention to resolve completely
Infections that develop as a complication of surgery
Caused by the invasion, resident, and proliferation of pathogens such as bacteria, viruses and fungi.

3. Outcomes of Microbial Invasion
Eradication
Containment leads to abscess (furuncle, carbuncle, hidradenitis suppurativa, intra-abdominal abscesses)
Locoregional infection (cellulitis, soft tissue infection, lymphangitis)
Systemic infection (bacteremia, fungemia)

4. Furuncle Cutaneous staph abscesses
Bacterial colinization begins in hair follicles and can cause cellulitis and abscess formation
Treatment with surgical drainage if large, antibiotics +/-

5. Carbuncles
Cutaneous abscess that spreads through the dermis into subcutaneous region
Common with diabetics
Treatment with I & D, antibiotics +/-

6. Intra-abdominal infection
Primary microbial peritonitis
Ascities, peritoneal dialysis
Tx: antibiotics
Secondary microbial peritonitis: contamination of the peritoneal cavity due to perforation or severe inflammation and infection of an intra-abdominal organ
Appendicitis, diverticulitis, perforation, etc.
therapy requires source control to resect the diseased organ; débridement of necrotic, infected tissue and debris; and administration of antimicrobial agents directed against aerobes and anaerobes

7. Intra-abdominal infection
Patients in whom standard therapy fails develop an intra-abdominal abscess, leakage from a gastrointestinal anastomosis leading to postoperative peritonitis, or tertiary (persistent) peritonitis.
Intra-abdominal abscess: perc drain vs. surgical intervention, short course of antibiotics

8. Organ Specific Infections
Hepatic abscesses
80% pyogenic, 20% parasitic and fungal
Pyogenic abscess treated with sampling and 4-6 weeks of antibiotics, larger abscesses may need perc drain.

9. Organ Specific Infections
Pancreatic necrosis
Develops in 10-15% of patients who develop severe hemorrhagic pancreatitis
Sterile and Infected necrosis
empiric antibiotic therapy with carbapenems or fluoroquinolones that achieve high pancreatic tissue levels reduce the incidence and severity of pancreatic infection
enteral feedings initiated early, using nasojejunal feeding tubes – prevents translocation of bacteria

10. Organ Specific Infections
Secondary pancreatic infection
Suspected in patients whose systemic inflammatory response (fever, elevated WBC count, or organ dysfunction) fails to resolve, or in those individuals who initially recuperate, only to develop sepsis syndrome 2 to 3 weeks later
CT-guided aspiration or identification of gas within the pancreas on CT scan, mandate operative intervention
50% mortality if no surgical intervention if infected necrosis
Lower mortality in sterile necrosis

11. Cellulitis
Inflammation of the dermal and subcutaneous tissues secondary to nonsuppurative bacterial invasion.
Redness, edema, and localized tenderness
May infect the lymphatics leading to lymphangitis
Treatment against Group A strep

12. Necrotizing Fasciitis
Rapidly progressive, multiple organisms, invades fascial planes
Causes vascular thrombosis as it progresses, resulting in necrosis of the tissues involved.
Overlying skin may be normal
Hemorrhagic bullae may develop from edema; crepitus; systemic toxicity
“dishwater gray” discharge with anaerobic infection
Group A strep, mixed anaerobes + coliforms, MRSA
Treatment is surgical debridement, send gram stain
Vanc, carbapenems, and Pen G

13. Surgical Site Infection
38% of nosocomial infections, 2-5% of patients
Factors:
Health of the patient
Operative technique
Timely administration of preoperative antibiotics
No benefit to antiseptic bath over other wash products
No benefit to barrier devices except gloves
Good surgical techniques: gentle traction, hemostasis, removal of devitalized tissue, obliteration of dead space, irrigation, wound closure without tension

14. Risk Factors
Microorganism: Remote site infection, long term care facility, duration of the procedure, wound class, ICU patient, prior antibiotic therapy, preop shaving, bacterial number, virulence, and antimicrobial resistance
Local Wound: Surgical technique – Hematoma/ seroma, necrosis, sutures, drains, foreign bodies
Patient: Age, immunosuppression, steroids, malignancy, obesity, diabetes, malnutrition, multiple comorbidities, transfusions, cigarette smoking, oxygen, temperature, glucose control

15. Risk Factors
Drains:
Should be omitted after hepatic, colonic, or rectal resection with primary anastomosis and after appendectomy for any stage of appendicitis
Should be used after esophageal resection and total gastrectomy
Contamination increases with duration of operation
Electrocautery: pinpoint coagulation, dividing tissue under tension decreases tissue destruction

16. Surgical Site Infection
Difference is SSI based on hand hygiene? Hand rubbing vs. hand scrubbing
Compliance 44% vs 28%

17. Wound classification
Clean wounds were defined as uninfected operative wounds in which no inflammation was encountered and the wound was closed primarily. By definition, a viscus (respiratory, alimentary, genital, or urinary tract) was not entered during a clean procedure.
Clean-contaminated wounds were defined as operative wounds in which a viscus was entered under controlled conditions and without unusual contamination.
Contaminated wounds included open, fresh accidental wounds, operations with major breaks in sterile technique or gross spillage from a viscus. Wounds in which acute, purulent inflammation was encountered also were included in this category.
Dirty wounds were defined as old traumatic wounds with retained devitalized tissue, foreign bodies, or fecal contamination or wounds that involve existing clinical infection or perforated viscus.

18. Antibiotic Prophylaxis
Timing: Percent of SSI for dose given early, preoperative, perioperative, and postop are 3.8, 0.6, 1.4 and 3.3 respectively
Prophylaxis with cefazolin has been effective for most clean procedures. Cefuroxime can be given for thoracic and ortho procedures.
For procedures that might involve bowel anaerobes, cefoxitin is more effective than cefazolin.

19. ABX Recs Colon/Whipple: Bowel prep/oral prophylaxis/ IV prophylaxis
Neomycin, Erythromycin, Cefoxitin
Cholecystectomy open or laparoscopic prophylaxis recommended for pt age>60, previous biliary surgery, acute symptoms, jaundice (benefit less clear with lap): cefoxitin or unasyn
Uncomplicated appendectomy: cefoxitin or unasyn
Penetrating abdominal trauma: Cefoxitin or Unasyn – continue post op for 24 hours
IHR: uncomplicated, no prophylaxis; complicated, cefoxitin
Mastectomy: no abx recommended
Vascular cases: Cefazolin

20. Other Recs Esophageal and gastroduodenal: Cefazolin
ERCP: routine abx prophylaxis does not reduce sepsis/cholangitis
Repeat dosing: Procedure lasting more than 4 hours or when major blood loss occurs
Continuation of Abx past 24 hours post op is not recommended
Hair removal with clippers immediately preop
Preop or postop hyperglycemia increase risk of SSI
Perioperative normothermia

21. Postoperative Nosocomial Infections
UTI
Pneumonia
Bacteremic Episodes
Sepsis Syndrome

22. UTI
Diagnosis should be considered with urinalysis positive for WBCs, bacteria, or a positive leukocyte esterase.
Confirmed with culture > 10K colonies in symptomatic patient or > 100K colonies in asymptomatic patient
Treatment with days with a single antibiotic that achieves high levels in the urine is appropriate
Remove catheter

23. Pneumonia High risk with prolonged mechanical ventilation
Frequently multi-resistant organisms
Diagnosis by Xray
BAL with gram stain and culture
Antibiotics based on local antibiogram with beta-lactam, aminoglycoside or fluoroquinolone, and vanc or linezolid.
Treat for 7-8 days

24. Bacteremic Episodes Indwelling catheters
25% of catheters will become colonized, and 5% will be associated with bacteremia
Prolonged insertion, insertion under emergency conditions, manipulation under nonsterile conditions, and perhaps the use of multilumen catheters increase the risk of infection.
Confirmed with blood culture from peripheral site and catheter that grow same bacteria
Treatment is removal of catheter.
In patients with difficult access and grow low virulence bugs, such as S. epidermidis, treatment with days of antibiotics is effective 50-60% of the time.

25. Sepsis Syndrome Empiric antimicrobial therapy, institution specific
Fluid rescucitation
Metabolic support
Site specific infection control
Appropriate therapy associated with two to three fold reduction in mortality
Low dose steroid for patients with hypotension refractory to vasopressors
STIM test
Hydrocortisone 100mg/8hr vs. continuous infusion
Xigris associated with 6% reduction in mortality
antithrombotic, profibrinolytic, and anti-inflammatory properties
Consider in patients with severe infection and at least one organ failing