Clinical profile and outcome of Stenotrophomonas maltophilia infections among adult patients admitted at the University of Santo Tomas Hospital: A seven-year retrospective study

ABSTRACT

INTRODUCTION: Stenotrophomonas maltophilia is an aerobic gram-negative rod of low virulence. However, it is becoming an important cause of nosocomial infections usually among susceptible patients. More data in the local setting is needed to help clinicians recognize this emerging cause of infection. OBJECTIVE: Determine the clinical profile and outcome of S. maltophilia infections among adult patients admitted at the University of Santo Tomas Hospital over a period of seven years. METHODOLOGY: This is a retrospective descriptive study. Medical records of all patients > 18 years old admitted and assessed to have S. maltophilia infection from January 1, 2006 to December 31, 2012 were available for review. RESULTS: Medical charts of 66 patients with S. maltophilia infection were reviewed. Seventy-two percent of these were hospital-acquired, whereas 28% were from the community. Most patients were male (57.6%), with a mean age of 68.97 ± 15.5 years. The lungs were the most common foci of infection (75.6%). Most common co-morbid illnesses were hypertension (54.5%) and diabetes mellitus (39.4%). Forty eight percent were on mechanical ventilatory support. Ninety five percent had invasive devices most notably indwelling urinary catheter (43%) and internal jugular catheter (13.6%). Fifty six percent (56.1%) received antibiotics prior to onset of S. maltophilia infection. Thirty six percent (36%) had polymicrobial infections associated with S. maltophilia. The organisms most frequently isolated were Klebsiella pneumonia (29.2%), Pseudomonas aeruginosa (25%), and Staphylococcus aureus (16.7%). Sixty percent of the isolates were fully susceptible to the recommended antibiotics. Only 1.5% were found to be multi-drug resistant. Majority (57.6%) of the patients were discharged improved, while 4.5% died due to S. maltophilia infection and 25.8% died from other causes mostly myocardial infarction. CONCLUSION: Stenotrophomonas maltophilia infections were mostly hospital acquired. Most of the organisms were isolated from the respiratory tract. Most commonly associated co-morbid illnesses included hypertension and diabetes mellitus. Other associated factors included mechanical ventilatory support, prior antibiotics use, and presence of indwelling catheters. Most of the isolates remained susceptible to the recommended antibiotics, however, a fraction were resistant, most notably to Cotrimoxazole. Majority of the patients were discharged improved. Mortality attributable to S. maltophilia was only 4.5%.