(609) Emerging Multidrug-Resistant Pathogen: Stenotrophomonas maltophilia Ventilator-Associated Pneumonia

Introduction: Stenotrophomonas maltophilia, a non-fermenting gram-negative rod, is the third most common nosocomial pathogen after Pseudomonas aeruginosa and Acinetobacter species. It is an environmental global emerging Gram-negative multi-drug resistant organism (MDRO) most associated with respiratory infections, hematologic malignancies, prolonged ICU stays, and mechanical ventilation.

Description: A 34-year-old male with a history of alcohol abuse and prior pancreatitis was admitted with epigastric pain radiating to his back. Laboratory workup revealed a white blood cell count of 18,000/μL, lactate level of 6.4 mmol/, serum creatinine of 1.8 mg/dL and lipase level of 2016 U/L. Despite initial management, he developed a progressive respiratory and mental status deterioration and was transferred to the ICU for emergent intubation and pressor requirement complicated by severe alcohol withdrawal. He was treated with empiric antibiotics, starting with ceftriaxone followed by meropenem. His hospital course was complicated by persistent fevers raising concerns for ventilator-associated pneumonia (VAP) and a sputum culture from the endotracheal tube (ETT) grew Stenotrophomonas maltophilia. A CT showed dense bibasilar consolidations with some air bronchograms, indicative of pneumonia.

Discussion: Stenotrophomonas maltophilia has emerged as a challenging nosocomial pathogen due to its intrinsic multidrug resistance and the complexity of its infections. Complementary exams, such as sputum culture, are essential for diagnostic confirmation and guiding appropriate therapy. In this patient, the culture identified S. maltophilia, and the antibiogram showed sensitivity to levofloxacin and sulfamethoxazole/trimethoprim. Treatment with sulfamethoxazole/trimethoprim successfully resolved the patient's fever and respiratory status. Risk factors in this case included prolonged ICU stay, mechanical ventilation, and prior broad-spectrum antibiotic use. Understanding these factors is critical for improving patient outcomes. Effective management requires optimized dosing of existing and investigational therapeutic options, targeting specific infection sites to minimize resistance development.