3.2 Antimicrobial Stewardship & Perioperative Care

3.2 Antimicrobial Stewardship & Perioperative Care

Urologists perform a diverse spectrum of interventions ranging from clean-contaminated endoscopic procedures to major extirpative surgeries. Optimizing surgical outcomes requires strict adherence to antimicrobial stewardship, rigorous evidence-based perioperative antithrombotic management, and immediate readiness for toxicological emergencies.

---

1. Antimicrobial Stewardship & Surgical Antimicrobial Prophylaxis (SAP)

Antimicrobial stewardship in urology seeks to prevent post-procedural healthcare-associated infections (HAIs), bacteremia, and urosepsis while mitigating the selection pressure for multi-drug resistant (MDR) uropathogens and Clostridioides difficile colitis.

General Principles of Prophylaxis

• Target & Purpose: SAP is designed to achieve bactericidal tissue and urine concentrations at the exact moment of tissue instrumentation or incision, preventing colonization by commensal skin, rectal, or urothelial flora. SAP is not intended to sterilize pre-existing infected tissue or substitute for aseptic surgical technique.
• Timing: When indicated, administer intravenous prophylaxis within 60 minutes before incision or instrumentation. Start vancomycin or an intravenous fluoroquinolone within 120 minutes because infusion takes longer; antibiotic selection must follow current indications and local resistance guidance.
• Duration: A single preoperative dose is sufficient for many procedures; major surgery generally uses a regimen lasting no more than 24 hours. Follow procedure-specific guidance. Treatment of an established infection and extended preoperative antibiotics for selected high-risk PCNL patients are separate decisions, not reasons for routine prolonged postoperative prophylaxis.
• Re-dosing: Intraoperative re-dosing is indicated only if the surgical duration exceeds two half-lives of the antibiotic (e.g., cefazolin re-dosed at 3–4 hours) or if intraoperative blood loss exceeds 1,500 mL.

Procedure-Specific Prophylactic Regimens

• Diagnostic Endoscopy (Rigid/Flexible Cystoscopy, Urodynamic Studies): EAU recommends against routine antibiotic prophylaxis. Evaluate symptomatic infection separately; indiscriminate prophylaxis offers little absolute benefit and selects resistant organisms.
• Transurethral Resection: EAU recommends prophylaxis for TURP, but for TURBT recommends it in patients at high risk of postoperative sepsis. Select an agent using cultures, local susceptibility, allergies and renal function; possible regimens include a cephalosporin, aminopenicillin/beta-lactamase inhibitor or aminoglycoside.
• Endourological Stone Surgery (URS / RIRS): Single-dose SAP (cefuroxime, co-amoxiclav, or gentamicin) administered at anesthesia induction.
• Percutaneous Nephrolithotomy (PCNL): Give perioperative prophylaxis and obtain a preoperative urine culture. Treat UTI before stone removal; drain an infected obstructed system before definitive surgery. A single induction dose is suitable for standard-risk patients; an extended preoperative course can benefit higher-risk patients, such as those with a stent, nephrostomy or positive culture. Infected stones and high intrapelvic pressures promote pyelovenous bacterial/endotoxin entry, so a negative bladder culture does not eliminate sepsis risk.
• Radical Cystectomy with Urinary Diversion: Major clean-contaminated surgery requires prophylaxis against relevant skin and enteric organisms, including anaerobes when bowel is entered. A local protocol may use cefazolin/cefuroxime plus metronidazole; use cultures and resistance patterns to select alternatives. Routine prophylaxis should not exceed 24 hours.

Prostate Biopsy: Transperineal vs. Transrectal Paradigm Shift

Transrectal ultrasound-guided biopsy passes through rectal mucosa, introducing enteric flora into the prostate and bloodstream. Fluoroquinolone resistance increases infectious risk. European restrictions on fluoroquinolones followed disabling and potentially irreversible adverse effects; the prostate-biopsy prophylaxis indication was suspended. EAU recommends not using fluoroquinolones for prostate biopsy.

Preferred route: EAU strongly recommends transperineal biopsy, which avoids rectal puncture and lowers infectious complications. Use surgical disinfection of the perineal skin. EAU allows omission of prophylactic antibiotics in transperineal biopsy patients without infection risk factors (weak recommendation); assess higher-risk patients separately.

If transrectal biopsy is used: Combine povidone-iodine rectal cleansing with antibiotic prophylaxis. EAU favours rectal-swab/stool-culture-targeted prophylaxis, with augmented prophylaxis as another option. Rectal antisepsis is an adjunct, not a substitute for antibiotics. Choose agents under European restrictions and local susceptibility guidance.

---

2. Asymptomatic Bacteriuria (ASB)

Definition: Bacteriuria in a person without urinary infection symptoms. For voided urine, the diagnostic threshold is ≥10^5 CFU/mL, confirmed in two consecutive samples in women and one sample in men. Pyuria alone does not turn asymptomatic bacteriuria into symptomatic UTI.

When to Treat ASB (Strict Indications)

The two principal exam indications for screening and treatment are:

1. Prior to Urological Procedures Breaching the Urinary Mucosa: Transurethral resection of the prostate (TURP), TURBT, percutaneous nephrolithotomy (PCNL), ureteroscopy (URS), and transurethral enucleation. Breaching mucosal barriers leads to direct vascular entry of colonized bacteria, precipitating bacteremia and severe septic shock. Obtain a preoperative urine culture and give susceptibility-directed treatment before mucosa-breaching surgery. Distinguish this treatment from routine surgical prophylaxis.
2. Pregnant Women: Treatment reduces maternal pyelonephritis; pregnancy-specific drug selection and duration are required.

When NOT to Treat ASB (Strong Negative Recommendations)

Do not routinely screen or treat ASB in the following settings. A planned urinary intervention requires a separate assessment:

• Premenopausal or postmenopausal non-pregnant women;
• Patients with well-controlled or poorly controlled diabetes mellitus;
• Elderly, institutionalized nursing home residents;
• Patients with an indwelling urethral catheter or nephrostomy tube (catheter colonization is ubiquitous, and antibiotic administration rapidly selects for pan-resistant uropathogens without eradicating bacteriuria);
• Patients with neurogenic lower urinary tract dysfunction performing clean intermittent catheterization (CIC);
• Prior to joint arthroplasty or non-mucosal urological surgery.

Routine treatment does not improve outcomes in these groups and promotes adverse effects and resistance. This does not override treatment before mucosa-breaching surgery. Uncomplicated urethral catheter exchange needs no ASB treatment; nephrostomy or ureteric stent placement/exchange carries a different infection risk and warrants procedure-specific assessment.

---

3. Perioperative Antithrombotic Management

Managing patients on antiplatelet and anticoagulant medications requires balancing the procedural bleeding risk against the patient's individual thromboembolic risk.

Stratification of Urological Bleeding Risk

• High Bleeding Risk Procedures: Radical prostatectomy (open, laparoscopic, robotic), partial nephrectomy (high risk of arterial pseudoaneurysm and secondary hemorrhage), radical cystectomy, TURP / HoLEP / ThuLEP, percutaneous nephrolithotomy (PCNL), transrectal prostate biopsy, and percutaneous renal biopsy.
• Low Bleeding Risk Procedures: Diagnostic flexible cystoscopy, scrotal surgery (hydrocelectomy, vasectomy, epididymectomy), circumcision, ureteroscopy without aggressive stone basket extraction or dilation.

Antiplatelet Protocols (Aspirin & P2Y12 Inhibitors)

• Aspirin (Acetylsalicylic Acid - ASA): Irreversibly inhibits platelet COX-1 for the platelet lifespan (7–10 days).
  • Low bleeding risk: Aspirin can usually continue when there is an ongoing cardiovascular indication.
  • High bleeding risk: Balance bleeding against thrombotic risk. If interruption is chosen, a 5–7-day interval is commonly used; restart promptly once haemostasis permits, generally within 48 hours.
  • Prior coronary intervention: Continue aspirin if bleeding risk allows. Recent PCI or acute coronary syndrome requires a cardiology–surgery–anaesthesia plan; defer elective surgery until the appropriate antiplatelet course is completed, usually six months after elective PCI or twelve months after ACS. Time-sensitive surgery may need an earlier individualized plan.
• P2Y12 Receptor Inhibitors:
  • Clopidogrel: Stop 5 days before high-risk procedures.
  • Ticagrelor: Reversible binding; stop 3 to 5 days before high-risk procedures.
  • Prasugrel: Irreversible; stop 7 days before high-risk procedures.

Anticoagulation Protocols (Warfarin & DOACs)

• Vitamin K Antagonist (Warfarin): Stop 5 days preoperatively; check INR on the morning of surgery (target INR < 1.5 for major urological procedures).
  • Heparin Bridging: Therapeutic LMWH bridging (e.g., enoxaparin 1 mg/kg twice daily) is considered for selected very-high-thrombotic-risk patients, balancing bleeding risk with specialist input. Examples include:
    • Mechanical mitral valve or older mechanical caged-ball/tilting disc valve;
    • Non-valvular atrial fibrillation with CHA2DS2-VASc ≥ 7;
    • Venous thromboembolism (DVT/PE) within the previous 3 months;
    • Severe thrombophilia (e.g., antiphospholipid syndrome).
  • Patients with low or moderate thromboembolic risk do NOT receive bridging, as bridging significantly increases major bleeding without reducing arterial thromboembolism. If bridging is used, stop therapeutic LMWH 24 hours prior to surgery.
• Direct Oral Anticoagulants (DOACs - Apixaban, Rivaroxaban, Edoxaban, Dabigatran):
  • DOACs have rapid onsets (2–4 hours) and predictable half-lives (8–14 hours). Routine heparin bridging is NOT recommended for DOACs, as it drastically increases perioperative bleeding.
  • Factor Xa inhibitors (apixaban, rivaroxaban, edoxaban): Typically interrupt for at least 24 hours for low-risk surgery and 48 hours for high-risk surgery when renal clearance is adequate. Drug accumulation or neuraxial procedures may require a longer interval. A 24-hour interruption does not mean one omitted dose for every dosing schedule.
  • Dabigatran: Predominantly renally cleared. For high-bleeding-risk surgery, minimum interruption is 48 hours at renal function ≥80 mL/min, 72 hours at 50–79, and 96 hours at 30–49. Corresponding low-risk intervals are 24, 36 and 48 hours.
  • Postoperative resumption: After high-risk surgery, restart at 48–72 hours when haemostasis is secure; defer longer if bleeding risk remains unacceptable.

Specific Anticoagulant Reversal Agents

---

4. Local Anesthetic Systemic Toxicity (LAST)

Local anesthetic infiltration is routinely utilized in urological practice for periprostatic nerve blocks during prostate biopsy, penile ring blocks for circumcision, and vasectomy anesthesia. Common agents include lidocaine, bupivacaine, and ropivacaine.

Mechanism & Toxicity Profile

Local anesthetics block voltage-gated sodium channels on nerve axons. Systemic absorption or inadvertent direct intravascular injection produces systemic sodium channel blockade in the brain and myocardium. Bupivacaine is the most lipophilic and cardiotoxic agent, dissociating very slowly from cardiac sodium channels during diastole.

Clinical Presentation of LAST

Toxicity typically manifests in a biphasic progression within 1 to 5 minutes of injection:

1. Central Nervous System (CNS) Excitation: Initial perioral numbness, tongue paresthesia, metallic taste, visual disturbances, tinnitus, agitation, and speech slurring, escalating rapidly to generalized tonic-clonic seizures.
2. CNS Depression: Sudden loss of consciousness, coma, and respiratory arrest.
3. Cardiovascular Collapse: Progressive PR and QRS prolongation, refractory ventricular arrhythmias (ventricular tachycardia, torsades de pointes, ventricular fibrillation), profound bradycardia, marked negative inotropy, and asystole.

Resuscitation Protocol: 20% Lipid Emulsion

At the first sign of LAST, immediate systematic action is mandatory:

1. Stop Injection: Cease local anesthetic administration immediately and call for emergency code team and the LAST Rescue Kit.
2. Airway & Oxygenation: Secure the airway and deliver 100% oxygen. Maintain ventilation and avoid hypoxaemia, hypercapnia and acidosis, which worsen local anesthetic toxicity.
3. Seizure Management: Administer small doses of intravenous benzodiazepines (e.g., midazolam 1–2 mg). Avoid propofol if hemodynamic instability or bradycardia is present.
4. Definitive Antidote — Intravenous 20% Lipid Emulsion (ILE):
   • Administer an immediate IV bolus of 20% Lipid Emulsion at 1.5 mL/kg over 2 to 3 minutes (~100 mL in a 70 kg adult);
   • Initiate a continuous IV infusion at 0.25 mL/kg/min;
   • If instability persists, repeat the bolus and double the infusion rate to 0.5 mL/kg/min;
   • Continue lipid for at least 15 minutes after haemodynamic stability; maximum cumulative dose 12 mL/kg.
5. Mechanism of ILE Rescue: Functions via the "lipid sink" phenomenon (creates an intravascular lipid compartment that sequesters lipophilic local anesthetics away from cardiac and brain tissue) and direct metabolic activation of myocardial fatty acid oxidation.
6. ACLS Modifications: If cardiac arrest occurs, reduce individual epinephrine doses to <1 mcg/kg (avoid standard 1 mg boluses, which worsen arrhythmias and impair lipid resuscitation). Avoid vasopressin, calcium channel blockers, beta-blockers, and lidocaine.

Cleaning, Disinfection and Sterilisation

Cleaning removes soil and organic material. Disinfection inactivates microorganisms on objects but does not necessarily eliminate bacterial spores. Sterilisation is a validated process eliminating viable microorganisms, including spores. Antisepsis applies antimicrobial agents to living tissue; aseptic technique prevents contamination during care.

The device's intended contact determines the required processing:

Clean reusable equipment before disinfection or sterilisation: residual organic material can protect microorganisms. Follow the validated instructions for the instrument and processing system, including all channels, concentration, contact time, temperature, rinsing, drying and storage. Steam suits compatible instruments; heat-sensitive equipment needs a compatible validated method. A device's delicate construction does not justify inadequate processing.

Worked decision: A reusable endoscopic biopsy forceps will breach mucosa. Cleaning followed by high-level disinfection alone does not meet the critical-device standard: sterilise it using the specified compatible process. Prophylactic antibiotics cannot compensate for contaminated instruments.

Primary references: CDC definitions and processing recommendations. These microbiological principles do not replace applicable European device requirements or the manufacturer's instructions.