Preservation of viable Francisella tularensis for forensic analysis.

As a preservation solution, (1%) ammonium chloride may be preferred over other conventionally used storage solutions because of its compatibility with analytical techniques such as Mass Spectrometry. In this study, ammonium chloride performed as well or better than phosphate buffered saline with Tween or Butterfields/Tween for preserving Francisella tularensis subsp. novicida.

Comparing bacterial DNA microarray fingerprints.

Epidemiologic and forensic investigations often require assays to detect subtle genetic differences between closely related microorganisms. Typically, gel electrophoresis is used to compare randomly amplified DNA fragments between microbial samples, where the patterns of DNA fragment sizes are viewed as genotype 'fingerprints'. The limited genomic sample captured on a gel, however, is not always sufficient to discriminate closely related strains.

Bacterial analysis by MALDI-TOF mass spectrometry: an inter-laboratory comparison.

Bacterial analysis by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry has been demonstrated in numerous laboratories, and a few attempts have been made to compare results from different laboratories on the same organism. It has been difficult to understand the causes behind the observed differences between laboratories when different instruments, matrices, solvents, etc. are used.

Effect of culture conditions on microorganism identification by matrix-assisted laser desorption ionization mass spectrometry.

Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) has been used to identify bacteria based upon protein signatures. This research shows that while some different proteins are produced by vegetative bacteria when they are cultured in different growth media, positive identification with MALDI-TOF MS is still possible with the protocol established at the Pacific Northwest National Laboratory (K. H.

Quantitative oligonucleotide microarray fingerprinting of Salmonella enterica isolates.

We report on a genome-independent microbial fingerprinting method using nucleic acid microarrays for microbial forensics and epidemiology applications and demonstrate that the microarray method provides high resolution differentiation between closely related microorganisms, using Salmonella enterica strains as the test case. In replicate trials we used a simple 192 probe nonamer array to construct a fingerprint library of 25 closely related Salmonella isolates. Controlling false discovery rate for multiple testing at alpha = 0.