Risk factor analysis for postoperative pulmonary infections with multidrug-resistant bacteria in patients with oral squamous cell carcinoma undergoing flap repair surgery

To investigate the distribution patterns and risk factors for multidrug-resistant bacterial pulmonary infections in patients with oral squamous cell carcinoma (OSCC) undergoing flap reconstruction surgery, and to provide evidence for infection prevention and treatment in this population.

This study was approved by the institutional medical ethics committee. We retrospectively analyzed sputum culture results, antimicrobial susceptibility testing data, and clinical records of 109 OSCC patients undergoing flap reconstruction. Chi-square tests were employed to identify pathogens and risk factors for multidrug-resistant bacteria (MDR) in postoperative pulmonary infections. Multivariate logistic regression analysis was conducted to determine MDR risk factors and establish a nomogram prediction model. The model’s discriminatory power, accuracy, and clinical utility were evaluated using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

Among the 109 patients, 52 had negative sputum cultures and 57 tested positive, of whom 14 developed multidrug-resistant (MDR) pulmonary infections. Chi-square analysis revealed that blood transfusion, pre-existing pulmonary diseases, operation time ≥ 490 min, intraoperative blood loss ≥ 400 mL, and abnormal BMI were significant risk factors for postoperative MDR infections (P < 0.05). Multivariate logistic regression identified pre-existing pulmonary diseases, intraoperative blood loss ≥ 400 mL, abnormal BMI, and operative duration ≥ 490 min as independent risk factors for MDR infections (P < 0.05). The nomogram prediction model for MDR infections demonstrated an area under the ROC curve (AUC) of 0.874 (95% CI: 0.775-0.973). The calibration plot showed good agreement between predicted and observed outcomes. DCA indicated a net clinical benefit when the threshold probability for high-risk MDR infections ranged from 0.000 to 0.810. Common MDR pathogens included MDR Pseudomonas aeruginosa, MDR Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii (CRAB), and methicillin-resistant Staphylococcus aureus (MRSA).

Among OSCC patients undergoing flap reconstruction, MDR pulmonary infections were predominantly caused by gram-negative bacteria (including CRAB, MDR Pseudomonas aeruginosa, and MDR Klebsiella pneumoniae along with the gram-positive pathogen MRSA. Pre-existing pulmonary comorbidities, prolonged surgery duration (≥ 490 min), significant intraoperative blood loss (≥ 400 mL), and abnormal BMI were confirmed as independent risk factors for these MDR infections. The nomogram predictive model incorporating these four variables demonstrated clinically reliable accuracy in risk stratification for postoperative MDR pulmonary infections in this patient population.