An accelerated method for determining «self/non-self» microorganisms in the agglutination reaction

Abstract

A simple accelerated method for determining «self/non-self» microorganisms by using the agglutination reaction (RA) and therapeutic/prophylactic serum (Immunoglobulin complex preparation, lyophilized IgG, IgA, IgM immunoglobulins, developed by CSC Immuno-Gem, Moscow) is proposed to test for pathogenic, opportunistic and dominant probiotic Bifidobacteria spp. In parallel, all the microbial cell cultures examined were registered in the databases of Russia-wide and international collections and tested by the intermicrobial “self/non-self” recognition method, previously developed by us. 16 collection strains of various microorganisms were assessed by the RA with relevant therapeutic and prophylactic serum. Biological samples were obtained from the collection bacterial strains of Bifidobacterium bifidum 791, Escherichia coli LEGM-18, Klebsiella pneumoniae 278, Lactobacillus fermentum 90T-C4, Bifidobacterium longum MC-42, Escherichia coli M-17, Shigella sonnei 177b, Shigella flexneri 170, Escherichia coli 157, Staphylococcus aureus 209, Candida albicans 10231 and Salmonella serovar Enteritidis ATCC 10708. In addition, cell cultures obtained from the Museum of the Institute of Cellular and Intracellular Symbiosis UB RAS such as Bifidobacterium longum ICIS-505, Lactobacillus acidophilus ICIS-1127, Bifidobacterium bifidum ICIS-202, Bifidobacterium bifidum ICIS-310 were also included into the study. To assess microbial peptidoglycan foreignness, the intermicrobial “self/non-self” recognition method was also used based on inducing metabolites produced by the “dominant” test strain Bifidobacterium longum MC-42 after pre-incubation with metabolites collected from the studied cell cultures (“associates”) followed by established “dominant-associate” feedback loop. The data were evaluated by assessing change-fold in reproduction (growth/replication) and adaptation (biofilm formation and anti-lysozyme test) of microbial cultures in accordance with the described technique followed by comparing these two methods for intermicrobial “self/non-self” recognition. All the RA data were found to fully agree with those obtained after previous studies by using intermicrobial “self/non-self” recognition method coupled to “dominant-associate” system. Moreover, compared to analogous “intermicrobial recognition” method (5 days), ease of use and test timeframe (24 hours) allow to consider RA attractive for screening studies to select strains for scientific and industrial purposes.

Keywords

• persistence
• peptidoglycan
• «self/non-self» determination method
• agglutination reaction