Nonfermenting gram-negative rods isolated from respiratory samples from cystic fibrosis patients are difficult to identify using commercial systems.Thus,other testing platforms are being used to aid in accurate species identification.Which of the following systems has the advantage of a large curated database of proteomic profiles representative of many microorganisms and can give definitive organism identification within minutes?
A)Cellular fatty acid analysis
B)MALDI-TOF mass spectrometry
C)Multilocus sequence typing
D)Ribotyping of 16S rRNA gene

Question

Quizplus · Accepted Answer

When B.cepacia complex and other less frequently isolated nonfermenting gram-negative bacilli are identified by commercial systems in a patient with cystic fibrosis,species confirmation should be completed by additional phenotypic and/or genotypic methods.The B.cepacia complex has 18 genomovars,and appropriate speciation is crucial.MALDI-TOF mass spectrometry can identify many nonfermenters within minutes by generating a proteomic profile from an isolated colony.The MALDI-TOF instrument generates a proteomic profile (i.e. ,fingerprint)from abundant peptides and proteins in the sample (e.g. ,ribosomal peptides).Prepackaged software automatically generates identification by comparing the peptide profile with a curated database of representative microorganisms.

Nonfermenting Gram-Negative Rods Isolated from Respiratory Samples from Cystic Fibrosis