title: Evaluation of exudates by solid phase microextraction-gas chromatography.
abstract: Head-space solid phase microextraction combined with gas chromatography (SPME-GC) was used for the determination of bacterial volatile fatty acid (VFA) patterns. The method was validated with cultures of reference bacterial strains. It was confirmed that VFA production depends on the composition of the cultivation medium, which limits accurate characterisation of particular bacterial species. A set of 195 clinical exudates of various origin and consistence was analysed using SPME-GC and compared with 73 samples extracted using tert-butyl methyl ether. Approximate agreement of VFA profiles with cultivation findings was found in most cases. However, 20.5% of clinical exudates with distinct VFA profiles appeared to be false-negative by cultivation. Using SPME-GC of exudates, the frequency of false-negative cultivations was higher than that of solvent extraction of exudates or blood cultures found previously. The described method is suitable for preliminary detection of bacteria, particularly non-sporulating anaerobes, in clinical samples. It can reveal false-negative findings due to cultivation. Analysis can be performed in 30 min without the need for cultivation.
authors.affiliation: Department of Immunology and Microbiology, 1st Medical Faculty, Charles University, Katerinská 32, 121 08 2 Prague, Czech Republic. jaroslav.julak@lf1.cuni.cz
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Julák
authors.forename: Eva
authors.initials: E
authors.lastname: Procházková-Francisci
authors.forename: Eva
authors.initials: E
authors.lastname: Stránská
authors.forename: Vlasta
authors.initials: V
authors.lastname: Rosová
mesh_terms: D001421:Bacteria, Anaerobic / Q000737:chemistry*; D001424:Bacterial Infections / Q000175:diagnosis; D002849:Chromatography, Gas / Q000379:methods*; D005069:Evaluation Studies as Topic; D005232:Fatty Acids, Volatile / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D008738:Methyl Ethers / Q000032:analysis*
chemical_list: D005232:Fatty Acids, Volatile; D008738:Methyl Ethers; C043243:methyl tert-butyl ether