Evaluation of Hospital-Acquired Stenotrophomonas maltophilia Infections

Introduction: This study was performed to evaluate the incidence, risk factors, clinical characteristics, antimicrobial susceptibility patterns, and crude mortality of hospital-wide hospital-acquired Stenotrophomonas maltophilia infections. Patients and Methods: A prospective surveillance study was performed from January 2000 through December 2009. Hospital-acquired infections were defined according to the standard definitions of the Centers for Disease Control and Prevention (CDC). Results: During the study period, hospital-acquired S. maltophilia infection was diagnosed in 52 patients. S. maltophilia constituted 1.1% of hospital-acquired infection isolates and 1.5% of gram-negative microorganisms. The overall incidence was found as 2.1 per 10.000 hospital admissions. Patients with hospital-acquired S. maltophilia infection were documented in surgical wards (38%), medical wards (31%), and the intensive care unit (31%). The clinical manifestations were pneumoniae (38%), surgical site infection (25%), central venous catheter-related bloodstream infection (13%), urinary system infection (13%), peritonitis (6%), and skin and soft tissue infection (4%). The most common underlying diseases were malignancies (37%), chronic renal failure (15%), and cardiac failure (15%). Eighty-eight percent of the patients were on antibiotic treatment before infection. The most common antibiotics prescribed before the onset of infection were carbapenems and third-generation cephalosporins. The crude mortality was found as 13.5%. Trimethoprim-sulfamethoxazole (94%) and ciprofloxacin (79%) were found to be the most effective antibiotics against S. maltophilia. Conclusion: The incidence and mortality rate of S. maltophilia infections were found lower in our hospital. As S. maltophilia is associated with a high mortality rate and has high resistance to many currently available broad-spectrum antibiotics, it should be kept in mind in the etiology of a wide range of nosocomial infections in patients with risk factors