Abstract

Five species of bacteria including Escherichia coli, Mycobacterium smegmatis, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Enterobacter cloacae were deposited from suspensions of various titers onto disposable nitrocellulose filter media for analysis by laser-induced breakdown spectroscopy (LIBS). Bacteria were concentrated and isolated in the center of the filter media during centrifugation using a simple and convenient sample preparation step. Summing all the single-shot LIBS spectra acquired from a given bacterial deposition provided perfectly sensitive and specific discrimination from sterile water control specimens in a partial least squares discriminant analysis (PLS-DA). Use of the single-shot spectra provided only a 0.87 and 0.72 sensitivity and specificity, respectively. To increase the statistical validity of chemometric analyses, a library of pseudodata was created by adding Gaussian noise to the measured intensity of every emission line in an averaged spectrum of each bacterium. The normally distributed pseudodata, consisting of 4995 spectra, were used to compare the performance of the PLS-DA with a discriminant function analysis (DFA) and an artificial neural network (ANN). For the highly similar bacterial data, no algorithm showed significantly superior performance, although the PLS-DA performed least accurately with a classification error of 0.21 compared to 0.16 and 0.17 for ANN and DFA, respectively. Single-shot LIBS spectra from all of the bacterial species were classified in a DFA model tested with a tenfold cross-validation. Classification errors ranging from 20% to 31% were measured due to repeatability limitations in the single-shot data.

© 2022 The Author(s)

Pathogen identification with laser-induced breakdown spectroscopy: the effect of bacterial and biofluid specimen contamination

Qassem I. Mohaidat, Khadija Sheikh, Sunil Palchaudhuri, and Steven J. Rehse
Appl. Opt. 51(7) B99-B107 (2012)

Towards the clinical application of laser-induced breakdown spectroscopy for rapid pathogen diagnosis: the effect of mixed cultures and sample dilution on bacterial identification

Steven J. Rehse, Qassem I. Mohaidat, and Sunil Palchaudhuri
Appl. Opt. 49(13) C27-C35 (2010)

Laser-induced breakdown spectroscopy of bacterial spores, molds, pollens, and protein: initial studies of discrimination potential

Alan C. Samuels, Frank C. DeLucia, Kevin L. McNesby, and Andrzej W. Miziolek
Appl. Opt. 42(30) 6205-6209 (2003)

Importance evaluation of spectral lines in Laser-induced breakdown spectroscopy for classification of pathogenic bacteria

Qianqian Wang, Geer Teng, Xiaolei Qiao, Yu Zhao, Jinglin Kong, Liqiang Dong, and Xutai Cui
Biomed. Opt. Express 9(11) 5837-5850 (2018)

Laser-induced breakdown spectroscopy used to detect palladium and silver metal dispersed in bacterial cellulose membranes

Madhavi Martin, Barbara Evans, Hugh O’Neill, and Jonathan Woodward
Appl. Opt. 42(30) 6174-6178 (2003)