Kasmera (Aug 2005)
Phenotypic Characterization and Antimicrobial Susceptibility in Clinical Strains of Stenotrophomonas maltophilia
Abstract
Stenotrophomonas maltophilia, previously known as Xanthomonas maltophilia and Pseudomonas maltophilia, is a Gram negative rod, and a non fermentator of glucose, recognized as a causal agent of diverse hospital infections, it also shows resistance to multiple antimicrobial agents. The objective of the present study was to identify and to characterize phenol-type, clinical isolates of S. maltophilia, as well as to establish an in vitro activity pattern of different antimicrobials. The bacterial strains were isolatde in the Bacteriology Laboratory at the General Hospital in Cumaná, and were identified through conventional biochemical tests, as well as using the commercial galleries of API ID32GN. The MIC of the anti-microbes was determined by dilution in Mueller Hutton agar following CLSI norms. Pheno-typically, 24 strains were identified of S. maltophilia. The identification was 100% coincident with both classification techniques. The uniform pattern was maintained for the isolates except for the oxidase test, where 17 (70.83%) were positive and 7 (29.17%) negative. The results of the identification test showed the presence of 5 phenotypes in which the typical pattern of the microorganism (phenotype I, 14 isolates) prevailed. The strains showed 100% resistance to imipenem, cefepime, amikacin and nalidixico, 95.83% to cefotaxime, ceftazidime and ampicillin- sulbactam, 91,67% to ceftriaxone and ciprofloxacin, and 75.00% to piperacillin-tazobactam, all of which showed more susceptibility to trimetoprim sulfametoxazole (91.67%), levofloxacin (75%) and rifampin (95.83%)
