Infection and Antibiotics

TEST TAKING TIP

WOUNDS

Name factors that influence the development of infection:

• Poor approximation of tissue, hematoma/seroma, hypothermia, long operation (>2 hours), excessive local tissue destruction/necrotic tissue, low blood flow, foreign body, dead space, and strangulation of tissues by tight sutures

Most common nosocomial infection:

• Urinary tract infection (UTI)

How many colony-forming units (CFUs) are needed on urine culture to confirm a diagnosis of UTI?

• >100,000 CFU

Most common nosocomial infection causing death:

• Pneumonia

Overall most common organism in surgical wound infections:

• Staphylococcus aureus

Most common anaerobe in surgical wound infections:

• Bacteroides fragilis

When do wound infection classically arise?

• Postoperative day 5 to 7

Treatment for a wound infection:

• Remove sutures/staples, culture wound, examine to rule out fascial dehiscence, leave wound open and pack, start antibiotics

Bacteria that will cause wound infection and fever within 24 hours after surgery:

• Group A β-hemolytic Streptococcus and Clostridium perfringens

Organisms that can cause necrotizing soft tissue infections:

• Group A β-hemolytic Streptococcus and Clostridium perfringens

Usual organism to cause necrotizing fasciitis:

• Polymicrobial (anaerobes with gram-negative organisms)

Time period to wait before obtaining a CT scan to look for postoperative abscess:

• >POD no. 7 (otherwise abscess may look like normal post-op fluid collection)

Findings on CT scan to indicate abscess:

• Gas in fluid collection, fibrous ring surrounding fluid collection

Usual initial treatment for intraabdominal abscess:

• Percutaneous drainage

Most common bacteria to cause a line infection:

• Staphylococcus epidermidis

How many CFUs are needed from a central line culture to indicate line infection?

• >15 CFU

In what instance should a central line be changed over a guidewire?

• Fever without obvious external signs of infection (catheter tip culture should be sent)

A line changed over ...