Stenotrophomonas maltophiliabacteraemia in Turkish children

Abstract

Stenotrophomonas maltophilia is an important cause of life-threatening nosocomial infection. To evaluate the clinical features, antibiotic treatment and prognosis of S. maltophilia bacteraemia. Patients with blood cultures positive for S. maltophilia at the Children's Hospital, Ankara University Medical School between 1995 and 2005 were evaluated retrospectively. The results were compared with those of a case-control group of patients with Pseudomonas aeruginosa bacteraemia (n=33). Antibiotic susceptibilities of S. maltophilia strains were determined by disc diffusion. Susceptibility to ciprofloxacin was also determined by broth dilution. Thirty-six (2.2%) blood cultures were positive for S. maltophilia. Neutropenia was more common in the P. aeruginosa group (p=0.001). Breakthrough bacteraemia developed more commonly during carbapenem treatment in the S. maltophilia group (p=0.02). Ciprofloxacin and trimethoprim-sulfamethoxazole in combination with/without an aminoglycoside were the antibiotics most commonly selected to treat S. maltophilia bacteraemia. Mortality was more common in the P. aeruginosa (13/33) than in the S. maltophilia (2/33) group (p=0.001). According to susceptibility, determination by the disk diffusion method, beta-lactam antibiotics, aminoglycosides and chloramphenicol had little or no effect, whereas trimethoprim-sulfamethoxazole, doxycycline and fluoroquinolones were more active against S. maltophilia strains. However, ciprofloxacin susceptibility results were quite different when determined by disk diffusion (97% isolates susceptible) and broth dilution (49% isolates susceptible). Although S. maltophilia bacteraemia is rare in children, antibiotic resistance to these strains is an important problem. Tetracyclines, trimethoprim-sulfamethoxazole and fluoroquinolones are the most active agents against S. maltophilia strains.