Surgical Site Infection (SSI) is one of the most common complications during the perioperative period. It not only prolongs hospital stay and increases medical costs but may also affect surgical outcomes and even endanger patients’ lives.

With the growing challenge of antimicrobial resistance, how to scientifically and appropriately use perioperative antibiotics has become a key topic in modern surgical infection management.

HongKong DengYueMed will systematically introduce the indications, principles of antibiotic selection, timing of administration, and duration management of perioperative antibiotics to provide reference for clinical practice.

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What Are Perioperative Antibiotics?

The perioperative period refers to the entire time span from when a patient is scheduled for surgery to full postoperative recovery, including:

• Preoperative stage
• Intraoperative stage
• Postoperative stage

Perioperative antibiotics mainly include two categories.

1. Prophylactic Antibiotics

Used to prevent potential surgical site infections. This is the most common clinical application.

2. Therapeutic Antibiotics

Used to treat existing infections, such as:

• Perforated appendicitis
• Intra-abdominal abscess
• Suppurative cholecystitis

This article focuses on the rational use of prophylactic antibiotics.

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Which Surgeries Require Prophylactic s?

Not all surgical procedures require routine antibiotic use.

Based on wound contamination level, surgeries are generally classified into four categories.

Class I Incision (Clean Surgery)

No entry into the respiratory, gastrointestinal, or genitourinary tracts.

Examples include:

• Thyroid surgery
• Benign breast tumor resection
• Hernia repair

In general, prophylactic antibiotics are not required.

However, they may be considered in patients with:

• Elderly age
• Diabetes
• Immunocompromised status
• Prosthetic device implantation

Class II Incision (Clean-Contaminated Surgery)

Entry into natural body cavities without significant contamination.

Examples include:

• Gastrointestinal surgery
• Biliary surgery
• Gynecological surgery
• Urological surgery

Prophylactic antibiotics are generally recommended.

Class III Incision (Contaminated Surgery)

There is a significant risk of contamination.

Examples include:

• Open traumatic wounds
• Gastrointestinal content spillage

Antibiotic therapy is generally required rather than simple prophylaxis.

Class IV Incision (Infected Surgery)

Existing infection is already present.

Examples include:

• Intra-abdominal abscess
• Gangrenous appendicitis
• Perforated peritonitis

In these cases, antibiotics are administered for therapeutic purposes.

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Principles of Perioperative Antibiotic Selection

Target the Most Likely Pathogens

Prophylactic antibiotics should cover the organisms most commonly associated with the planned procedure rather than providing unnecessarily broad-spectrum coverage.

Common pathogens include:

• Staphylococcus aureus
• Coagulase-negative staphylococci
• Escherichia coli
• Klebsiella pneumoniae
• Enterococcus species
• Anaerobic bacteria

Prefer Narrow-Spectrum Antibiotics

Whenever appropriate, narrow-spectrum antibiotics should be preferred because they help:

• Reduce antimicrobial resistance
• Preserve normal microbiota
• Reduce adverse drug reactions

High Safety and Good Tissue Penetration

An ideal prophylactic antibiotic should have:

• Good tissue penetration
• Adequate half-life
• Low toxicity
• Cost-effectiveness

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Common Perioperative Antibiotics and Clinical Use

First-Generation Cephalosporins

Cefazolin

Cefazolin remains one of the most widely recommended prophylactic antibiotics in international guidelines.

Common indications include:

• Orthopedic surgery
• Cardiothoracic surgery
• Vascular surgery
• General surgery

Advantages include:

• Excellent Gram-positive coverage
• High safety profile
• Extensive clinical experience

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Second-Generation Cephalosporins

Cefuroxime

Commonly used in:

• Thoracic surgery
• Gynecological surgery
• Urological surgery

Compared with first-generation cephalosporins, Cefuroxime offers improved Gram-negative coverage.

Cefoxitin and Cefmetazole

Often recommended for:

• Colorectal surgery
• Appendectomy
• Gynecologic pelvic surgery

These agents also provide effective anaerobic coverage.

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Alternatives for β-Lactam Allergic Patients

For patients with severe penicillin or cephalosporin allergy, alternatives include:

• Clindamycin
• Vancomycin

If broader Gram-negative coverage is needed, these agents may be combined with:

• Gentamicin
• Aztreonam

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Timing of Administration: More Important Than the Drug Itself

Evidence from multiple clinical studies shows that correct timing is one of the most important determinants of prophylactic efficacy.

Recommended Timing

For most antibiotics:

Administration should be completed 30–60 minutes before surgical incision to ensure adequate tissue concentrations at the beginning of surgery.

Special Drugs

For medications requiring prolonged infusion time, including:

• Vancomycin
• Fluoroquinolones

Administration should begin approximately 120 minutes before incision.

Intraoperative Redosing

Additional doses should be considered when:

• Surgery lasts longer than two drug half-lives
• Blood loss exceeds 1500 mL
• Massive fluid replacement is performed

For example, Cefazolin is generally redosed every 4 hours during prolonged operations.

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Duration Management of Perioperative Antibiotics

Single-Dose Strategy

For many clean surgical procedures, a single preoperative dose is sufficient.

Examples include:

• Joint replacement
• Breast surgery
• Hernia repair

24-Hour Discontinuation Principle

Most international guidelines recommend discontinuing prophylactic antibiotics within 24 hours after surgery.

This recommendation represents one of the core principles of antimicrobial stewardship.

Avoid Prolonged Prophylactic Use

Historically, antibiotics were frequently continued for:

• 3 days
• 5 days
• 7 days or longer

However, current evidence demonstrates that prolonged prophylaxis:

• Does not further reduce SSI rates
• Increases antimicrobial resistance
• Raises the risk of Clostridioides difficile infection
• Increases hepatic and renal toxicity
• Raises healthcare costs

Routine prolonged prophylaxis is therefore no longer recommended.

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Common Misconceptions in Perioperative Antibiotic Use

Myth 1: Stronger Antibiotics Are More Effective

Prophylaxis does not require the broadest-spectrum antibiotics.

Routine use of agents such as:

• Carbapenems
• Tigecycline
• Polymyxins

provides little additional benefit while increasing resistance.

Myth 2: Antibiotics Should Continue Until Surgical Drains Are Removed

Current guidelines clearly state that prophylactic antibiotics should not be continued simply because drains remain in place.

Myth 3: Every Patient Should Receive the Same Regimen

Antibiotic selection should consider:

• Surgical procedure
• Patient-specific risk factors
• Local resistance patterns
• Allergy history

Individualized management is essential.

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Future Trends: Precision and Antimicrobial Stewardship

With the continued development of Antimicrobial Stewardship Programs (ASP), perioperative antibiotic management is becoming increasingly precise.

Future priorities include:

• Selection based on local resistance surveillance
• Individualized dosing strategies
• Optimized administration timing
• Reduced unnecessary treatment duration
• Multidisciplinary collaboration

These strategies aim to reduce surgical infections while minimizing antimicrobial misuse.

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Conclusion

Appropriate perioperative antibiotic prophylaxis remains one of the most effective strategies for reducing Surgical Site Infection (SSI) and improving surgical safety.

As antimicrobial resistance continues to emerge as a global public health challenge, healthcare systems are transitioning from empirical antibiotic use toward standardized, evidence-based management. In this process, adherence to clinical guidelines, robust infection control systems, and reliable pharmaceutical supply all contribute to improved patient outcomes.

As a global pharmaceutical distributor, DengYueMed focuses on connecting Chinese pharmaceutical manufacturers with healthcare providers worldwide. Through comprehensive pharmaceutical sourcing and international distribution services, DengYueMed supports the accessibility and continuity of essential clinical medicines while helping healthcare systems meet evolving treatment needs.