Postoperative pneumonia after lung resection: a prospective double-blind comparative study of bronchial colonization and antibiotic prophylaxis.

Background: Postoperative pneumonia (POP) remains a major cause of morbidity after lung cancer surgery. The role of perioperative antibiotic prophylaxis (PAP), particularly the choice of antibiotics and their adjustment to bronchial colonization, is still debated. Methods: We conducted a prospective, double-blind, comparative study including 200 patients with primary lung malignancy undergoing lung resection. Patients received either cefazolin or amoxicillin-clavulanic acid as PAP. Preoperative bronchial colonization was assessed before surgery. The primary outcomes were the incidence of POP according to the antibiotic regimen and colonization status. Results: The cohort comprised 200 patients (median age 68 years, range 44-83; 48.5% women). POP occurred in 47 patients (23.5%). Of these, 23 (21.5%) had received cefazolin and 24 (25.8%) amoxicillin-clavulanic acid, with no significant difference between regimens. Colonization was detected in 178 patients (89.0%), including 36 (20.2%) with potentially pathogenic microorganisms (PPMs). POP incidence was similar in non-colonized (22.7%), colonized (23.6%), and PPM-colonized patients (25.0%) (all Conclusions: In this prospective comparative study, POP after lung cancer surgery did not significantly differ according to the prophylactic antibiotic regimen or colonization status. However, given the relatively small number of patients with PPM colonization and the single-center design, these findings should be interpreted cautiously. Standard perioperative prophylaxis with cefazolin appears appropriate, while routine preoperative colonization screening may not be necessary. Further studies are needed to better define risk-adapted preventive strategies.