Critical aspects of analysis of Micrococcus luteus, Neisseria cinerea, and Pseudomonas fluorescens by means of capillary electrophoresis

Abstract

Within the frame of our study we investigated Microccocus luteus, Neisseria cinerea, and Pseudomonas fluorescens by means of capillary zone electrophoresis (CZE). They form chains and clusters on a different scale, which can be reflected in the electropherograms. A low buffer concentration of Tris-borate and Na2EDTA containing a polymeric matrix of 0.0125% poly(ethylene) oxide (PEO) was used. Key factors were the standardization and optimization of CE conditions, buffer solution, and pretreatment of bacterial samples, which are not transferable to different bacterial strains, in general. The different compositions of the cell wall of on the one hand Gram-positive (M. luteus) and Gram-negative (N. cinerea) cocci and on the other hand Gram-negative, rod-shaped bacteria (P. fluorescens), are probably responsible for the different pretreatment conditions.

Combined capillary electrophoresis and DNA‐fluorescence in situ hybridization for rapid molecular identification of Salmonella Typhimurium in mixed culture

“…Although CE represents a promising approach for such microbial separations, it is essentially a phenotypic approach and therefore may suffer from certain limitations as a diagnostic method. For example, pleiomorphic or chain-forming cells may not be resolved adequately via CE, due to the wide range of cell surface charge values occurring within these populations [4,13]. Conversely, it may be difficult to separate closely related cell types, such as Salmonella Typhimurium and Escherichia coli due to their physiological similarities.…”

The effect of aggregation on the separation performance of bacteria in capillary electrophoresis

“…The latter was reported as depending on the bacteria species, the applied voltage, the buffer composition, the injection volume and the cell concentration [18,20]. Buffer and sample composition (cell concentration, matrix components in real samples) [15,16,18,[24][25][26], bacteria growth phase [27] and storage conditions [27] were factors that influenced peak shapes and migration times. Migration time shifts were also observed when mixtures of bacteria species had been injected [18,28].…”

Detection of microbial food contaminants and their products by capillary electromigration techniques

“…In successive years, several laboratories directed their studies toward the analysis of microorganisms with interest in food industry, clinical diagnosis and environmental control, using diluted polymer-based BGEs [44][45][46][47][48][49][50]. Shintani et al [44] successfully detected Salmonella enteritidis, the causative agent of a major foodborne disease, by CE and the aid of UV and LIF detectors.…”

“…Nevertheless, the reproducibility of the CE patterns obtained from the analysis of microorganisms by this strategy seems to be largely affected by variables such as BGE ionic strength, as well as by pretreatment, physiological state and storage conditions of cells [46]. In addition, Hoerr et al [47] reported that such susceptibility of the separation system to small experimental conditions variations also depends on the microorganisms under study. The diluted PEO-based BGE also proved to be invaluable for the rapid identification and quantitation of Edwardsiella tarda, a pathogen of commercially important fish [48].…”