Rapid inter-strain comparison by pyrolysis mass spectrometry of coagulase-negative staphylococci from persistent CAPD peritonitis

Abstract

SUMMARYPyrolysis mass spectrometry (PyMS) was used as a method of rapid inter-strain comparison of 19 isolates of coagulase-negative staphylococci from episodes of CAPD peritonitis. Thirteen isolates were from multiple, but distinct, episodes of peritonitis in 6 patients and the remaining 6 isolates were from 6 patients with single episodes. The results, expressed in terms of identity/non-identity of strains, were compared with those obtained using an established typing system comprising an extended antibiogram, determination of biotype and plasmid profile analysis. The PyMS results for inter-strain comparison were in agreement with the reference typing scheme results. PyMS can be used in this setting to rapidly obtain evidence that persistent infection is/is not likely to be due to the same organism, although it cannot be used for formal typing. The results by both methods showed that serial, apparently distinct, episodes of peritonitis over periods as long as 120 days may be due to the same strain of coagulase-negative staphylococcus. Clinically based distinctions between recurrence of infection (same strain) and re-infection (different strains) may not always be supported by the microbiological evidence.

Incrimination of an environmental source of a case of Legionnaires' disease by pyrolysis mass spectrometry

“…PyMS is a quick and reliable method of inter-strain comparison for many species, including streptococci [11], salmonellae [7] and staphylococci [8] and now, L. pneumophila, although the method does not yet offer formal type designations. To our knowledge this is the first occasion that PyMS has been used to trace an environmental source of clinical disease.…”

“…The 30 mass ion peaks showing the greatest discrimination between groups were subjected to principal component (PC) and canonical variate (CV) analyses, as in previous reports [7,8] ordination diagram (combined PCCV1 v. PCCV2) if their triplicate points did not overlap any from strains within the cluster. On sequential analyses these outliers were edited out of each data set until ordination diagrams showed that few, if any, triplicates overlapped.…”

Method Reproducibility and Spectral Library Assembly for Rapid Bacterial Characterization by Metastable Atom Bombardment Pyrolysis Mass Spectrometry

“…[2][3][4][5][6][7][8][9][10][11] Rapid methods for sub-typing analysis are crucial in clinical contexts, particularly to distinguish strains with respect to antibiotic resistance, acid resistance, toxin production capability, and other qualities that confer pathogenic character. During the last third of the past century, analytical chemists have periodically visited or revisited the potential use of mass spectrometric methods for rapid characterization of microbiological samples.…”