Clinical application of a rapid microbiological test based on capillary zone electrophoresis to assess local skin infection

Abstract

Background: The basic clinical problem associated with infection treatment is the fact that classic, commonly and routinely used isolation and identification methods are based on long-term processes of a phenotypic analysis of microorganisms. Consequently sometimes, especially in small centres, rapid implementation of antibacterial treatment becomes delayed.The work presents the initial results of rapid microbiological identification based on an original method of capillary zone electrophoresis (CZE). The study involved the analysis of 78 biological samples from post-operative wounds and trophic ulcers.

Results: The attempt was made to identify individual bacterial species based on characteristic features of electropherograms achieved. Finally, G(+) cocci type bacteria and different G(-) rods were identified with sensitivity of 88.1% and specificity of 100%.

Conclusions: Based on the clinical trials using an electrophoretic technique in the field of microbiological diagnostics of infected exudate from a post-operative wound it can be concluded that it is a rapid and relatively sensitive method for initial identification of infectious pathogens.

Figure 1

Algorithm for identification testing.

Figure 2

Characteristic spectra, obtained for different types of bacterial cells and for matrix.

Figure 3

Electropherogram of a biological smear from a wound in the phosphate buffer without the addition of PEO.

Figure 4

Electropherogram of the same biological smear from the wound, with the TBE buffer with PEO.

Figure 5

Background signals in the electropherogram of a biologic sample (matrix effect).

Figure 6

Electropherogram for E. coli bacteria.

Figure 7

Electropherogram for staphylococci.

Figure 8

Electropherogram for Pseudomonas aeruginosa.

Figure 9

Electropherogram for Enterobacter cloacae.

Figure 10

Electropherogram for the bacterial mixture. Time intervals when peaks appear are different from the ones for isolates.

Figure 11

Electropherogram for Streptococcus sp. (A) and Enterococcus faecium (B).

Figure 12

Electropherogram for a biological sample found sterile in the classic examination. Many high peaks typical for cocci (arrows) and a wide peak of biological sample background (the matrix effect) are visible.

Figure 13

A sample detection of additional strains in a biological sample in which only E. coli was detected using a conventional method.