title: In vivo and in vitro emergence of simultaneous resistance to both beta-lactam and aminoglycoside antibiotics in a strain of Serratia marcescens.
abstract: In a patient with Serratia marcescens bacteraemia, a variant resistant to cefotaxime and amikacin was isolated in a blood culture under combined treatment with cefotaxime and amikacin. In addition, in vitro selection on cefotaxime and/or amikacin yielded resistant mutants from the sensitive parent strain. These mutants displayed the same type of cross-resistance as the clinical strain to all beta-lactam and aminoglycoside antibiotics. The mechanism for this resistance was a decrease in the permeability of the cell. To our knowledge, the isolation of such strains from blood cultures and the mechanism responsible for this "broad-spectrum resistance" have not been previously described.
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D004352:Drug Resistance, Microbial; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D004756:Enterobacteriaceae Infections / Q000188:drug therapy / Q000382:microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018805:Sepsis / Q000188:drug therapy / Q000382:microbiology; D012706:Serratia marcescens / Q000187:drug effects*; D047090:beta-Lactams
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D047090:beta-Lactams