%0 Journal Article %A MASKELL, J. P. %T The pathogenicity of Bacteroides fragilis and related species estimated by intracutaneous infection in the guinea-pig %D 1981 %J Journal of Medical Microbiology, %V 14 %N 1 %P 131-140 %@ 1473-5644 %R https://doi.org/10.1099/00222615-14-1-131 %I Microbiology Society, %X SUMMARY. The pathogenicity of 42 strains of Bacteroides of human origin was estimated by intracutaneous injection of bacterial suspensions into guinea-pig skin. Comparisons of living and heat-killed suspensions revealed that B. fragilis strains maintained themselves and possibly multiplied in the skin, whereas the lesions induced by non-fra-gilis strains appeared to be due mainly to toxicity. Measurement of skin pathogenicity in terms of the number of viable organisms in the inoculum that produced a lesion 10 mm in diameter showed that B. fragilis was, on average, 17 times as pathogenic as non-fragilis strains. Skin tests of pathogens may be of value in the analysis of virulence factors of Bacteroides and possibly of other anaerobic organisms. %U https://www.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-14-1-131