First-Line Antibiotic for Surgical Prophylaxis
The answer is D) Cefazolin - it is the universally recommended first-line antibiotic for surgical prophylaxis across most surgical procedures.
Primary Recommendation
Cefazolin is the definitive first-choice antibiotic for surgical prophylaxis, recommended alone or in combination with metronidazole depending on the procedure. 1 The WHO Expert Committee, based on the principle of parsimony, selected only cefazolin as the standard first-line recommendation valid across surgical procedures. 1
Why Cefazolin is First-Line
Cefazolin is preferable for most procedures when prophylaxis is needed, as stated by the Australian Therapeutic Guidelines covering all surgical types including GI surgery, cardiac surgery, gynecological surgery, orthopedic surgery, and urological procedures. 1
The French Society of Anesthesia and Intensive Care Medicine (SFAR) recommends cefazolin for most cases where prophylaxis is indicated, including neurosurgery, cardiac and vascular surgery, orthopedic surgery, thoracic surgery, ORL procedures, GI surgery, urological procedures, and OB/Gyn procedures. 1
Cefazolin is a first-generation cephalosporin that provides appropriate coverage against the most common surgical site infection pathogens (primarily gram-positive cocci like Staphylococcus aureus and some gram-negative bacteria) without being overly broad-spectrum. 2, 3
Why the Other Options Are NOT First-Line
Ceftazidime (Option A) is a third-generation cephalosporin that is generally NOT recommended for surgical prophylaxis and should be reserved for therapeutic use. 2
Ciprofloxacin (Option B) is a fluoroquinolone mentioned only for special circumstances where no other options are available but was not formally proposed as first-line. 1 It has limited use in specific situations like prostate biopsy. 1
Amikacin (Option C) is an aminoglycoside not recommended as first-line surgical prophylaxis; gentamicin (another aminoglycoside) is listed only as a second-choice option. 1
Dosing and Timing
Administer cefazolin 2g IV within 30-60 minutes (ideally 1/2 to 1 hour) before surgical incision to ensure adequate serum and tissue concentrations at the time of initial incision. 4, 5
For procedures exceeding 4 hours, redose with cefazolin 1g intraoperatively to maintain adequate tissue levels. 4, 5
For patients weighing ≥120 kg or BMI >35 kg/m², consider cefazolin 3g for adequate dosing. 4
Duration of Prophylaxis
A single preoperative dose is generally sufficient for most procedures. 4, 3
Postoperative administration should be limited to a maximum of 24 hours, exceptionally 48 hours, and never beyond. 6, 3
Prolonging antibiotic prophylaxis beyond 24 hours increases the risk of antibiotic resistance without providing additional clinical benefit. 6
Critical Pitfall to Avoid
Ceftriaxone is often inappropriately used as first-line option in many settings and was specifically NOT prioritized by the WHO Working Group despite being commonly used. 1, 6 While ceftriaxone has been shown to be as effective as cefazolin in some studies, it is a third-generation cephalosporin that should be reserved for therapeutic use to minimize resistance. 7, 2
Do not administer antibiotics too early (>60 minutes before incision) as this reduces efficacy. 4
Do not continue antibiotics postoperatively as routine practice, as this increases resistance without reducing infection rates. 4