title: Influence of an extended incubation period on values of minimum inhibitory concentrations of antibiotics in Stenotrophomonas maltophilia clinical strains.
abstract: In 106 Stenotrophomonas maltophilia clinical strains the susceptibility to 19 kinds of antibiotics was tested by the broth dilution micromethod at 24 h and 48 h incubation. Isolated strains demonstrated the lowest frequency of resistance to cotrimoxazole (7.5% of resistant strains at 24 h incubation and 18.9% at 48 h), ofloxacin (13.2% and 30.2%), ciprofloxacin (19.8% and 50.9%) and to cefoperazone/sulbactam (20.8% and 37.7%). The smallest growth of the number of resistant strains after extended incubation was recorded in gentamicin (by 10.4%), ceftazidime (by 11.3%) and cotrimoxazole (by 11.4%). On the contrary, the largest growth of resistance was demonstrated in cefoperazone and ciprofloxacin (by 31.1%). Average values of the growth of minimum inhibitory concentrations (MICs) were lowest in ciprofloxacin and ofloxacin (2.3 times) and highest in piperacillin/tazobactam (4.5 times) and piperacillin (5.0 times). As far as the stability of MIC is concerned, the largest occurrence of strains with the MIC growth doubled as a maximum was found in ceftazidime (78.4%), ofloxacin (76.1%) and ciprofloxacin (75.3%), the smallest in piperacillin/tazobactam (43.2%) and piperacillin (38.9%). The importance of incubation extended to 48 h during the testing of S. maltophilia strains was noted for correctly setting their susceptibility to antibiotics.
authors.affiliation: Department of Microbiology, Faculty of Medicine, Palacký University, Olomouc, the Czech Republic.
authors.forename: P
authors.initials: P
authors.lastname: Hejnar
authors.forename: P
authors.initials: P
authors.lastname: Hamal
authors.forename: D
authors.initials: D
authors.lastname: Koukalová
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003428:Cross Infection / Q000382:microbiology; D004352:Drug Resistance, Microbial; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*; D020615:Stenotrophomonas maltophilia / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents