Transrectal ultrasound-guided prostate biopsy (TRPB) has been a standard of care for diagnosing prostate cancer but is associated with a high incidence of infectious complications.
To achieve an expert consensus on whether fosfomycin trometamol provides adequate prophylaxis in TRPB and discuss its role as prophylaxis in transperineal prostate biopsy (TPPB).
An international multidisciplinary group of experts convened remotely to discuss how to best use fosfomycin in various clinical settings and patient situations. Six statements related to prostate biopsy and the role of fosfomycin were developed, based on literature searches and relevant clinical experience.
Consensus was reached for all six statements. The group of experts was unanimous regarding fosfomycin as a preferred candidate for antimicrobial prophylaxis in TRPB. Fosfomycin potentially also meets the requirements for empiric prophylaxis in TPPB, although further clinical studies are needed to confirm or refute its utility in this setting. There is a risk of bias due to sponsorship by a pharmaceutical company.
Antimicrobial prophylaxis is mandatory in TRPB, and fosfomycin trometamol is an appropriate candidate due to low rates of resistance, a good safety profile, sufficient prostate concentrations, and demonstrated efficacy in reducing the risk of infectious complications following TRPB.
Patients undergoing transrectal ultrasound-guided prostate biopsy (TRPB) have a high risk of infectious complications, and antimicrobial prophylaxis is mandatory. However, increasing antimicrobial resistance, as well as safety concerns with fluoroquinolones, has restricted the number of antimicrobial options. Fosfomycin trometamol meets the requirements for a preferred antimicrobial in the prophylaxis of TRPB.

THAM (trometamol; tris-hydroxymethyl aminomethane) is a biologically inert amino alcohol of low toxicity, which buffers carbon dioxide and acids in vitro and in vivo. At 37 degrees C, the pK (the pH at which the weak conjugate acid or base in the solution is 50% ionised) of THAM is 7.8, making it a more effective buffer than bicarbonate in the physiological range of blood pH. THAM is a proton acceptor with a stoichiometric equivalence of titrating 1 proton per molecule. In vivo, THAM supplements the buffering capacity of the blood bicarbonate system, accepting a proton, generating bicarbonate and decreasing the partial pressure of carbon dioxide in arterial blood (paCO2). It rapidly distributes through the extracellular space and slowly penetrates the intracellular space, except for erythrocytes and hepatocytes, and it is excreted by the kidney in its protonated form at a rate that slightly exceeds creatinine clearance. Unlike bicarbonate, which requires an open system for carbon dioxide elimination in order to exert its buffering effect, THAM is effective in a closed or semiclosed system, and maintains its buffering power in the presence of hypothermia. THAM rapidly restores pH and acid-base regulation in acidaemia caused by carbon dioxide retention or metabolic acid accumulation, which have the potential to impair organ function. Tissue irritation and venous thrombosis at the site of administration occurs with THAM base (pH 10.4) administered through a peripheral or umbilical vein: THAM acetate 0.3 mol/L (pH 8.6) is well tolerated, does not cause tissue or venous irritation and is the only formulation available in the US. In large doses, THAM may induce respiratory depression and hypoglycaemia, which will require ventilatory assistance and glucose administration. The initial loading dose of THAM acetate 0.3 mol/L in the treatment of acidaemia may be estimated as follows: THAM (ml of 0.3 mol/L solution) = lean body-weight (kg) x base deficit (mmol/L). The maximum daily dose is 15 mmol/kg for an adult (3.5L of a 0.3 mol/L solution in a 70kg patient). When disturbances result in severe hypercapnic or metabolic acidaemia, which overwhelms the capacity of normal pH homeostatic mechanisms (pH < or = 7.20), the use of THAM within a \'therapeutic window\' is an effective therapy. It may restore the pH of the internal milieu, thus permitting the homeostatic mechanisms of acid-base regulation to assume their normal function. In the treatment of respiratory failure, THAM has been used in conjunction with hypothermia and controlled hypercapnia. Other indications are diabetic or renal acidosis, salicylate or barbiturate intoxication, and increased intracranial pressure associated with cerebral trauma. THAM is also used in cardioplegic solutions, during liver transplantation and for chemolysis of renal calculi. THAM administration must follow established guidelines, along with concurrent monitoring of acid-base status (blood gas analysis), ventilation, and plasma electrolytes and glucose.