Research Journal of Microbiology1816-4935xxxx-xxxxScience International10.3923/jm.2015.158.169FolorunsoO.S. AmisuK.O. OgungbeB.F. 42015104The ability of microbial cell membrane to bind organic dye is an age long protocol that preludes the identification and characterization of bacteria cells and its components. We employed formation of keratoconjunctivitis, pigmentations and Congo red binding assay to assess the virulence of eight enteric pathogenic bacteria. Staphylococcus aureus and Salmonella typhimurium, at 3.0×108 CFU mL-1, was sufficient to cause keratoconjunctivitis in the eyes of Albino rat (Sereny test), while observing traces in Streptococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Bacillus subtilis. Pigmentation (PCr+) occurred in Staphylococcus aureus, Streptococcus faecalis and Klebsiella pneumoniae. Highest protein secretion was found in Escherichia coli. Hydrophobicity of the microbial cell membrane increased in the order of chemical pre-treatments (0.9% w/v physiological saline, 50 mM Tris HCl, pH 7.8, 50 mM Tris HCl, pH 7.8+50 mM EDTA). Thus, Tris-EDTA adjunct increased hydrophobicity of the membrane to bind more Congo red than other treatments. Virulence strains of Gram-positive bacteria may likely cause a more severe keratoconjunctivitis. Pigmentations favoured Gram-positive than negative probably because of the membrane differentiation. The effect of multiple subculturing on the Congo red binding ability of these bacteria remained inconclusive as less than half of the tested bacteria complied with our hypothesis though, all were expectedly affected, when pre-treated. The virulence of bacteria is pre-determined by the inherent plasmid factors but their expression is a function of the bacteria cells to bind organic dye. Therefore, physico-chemical treatments that promote hydrophobicity of the bacteria cell membrane are likely to reduce their virulence.]]>Adamus, G. and E. Romanowska,1979Shigella sonnei. II. Comparative studies on virulent and avirulent strains of phase I.]]>28553558Alakomi, H.L., A. Paananen, M.L. Suihko, I.M. Helander and M. Saarela,20067246954703Berg, G., M. Alavi, M. Schmid and A. Hartmann,20132013pp: 1209-1216pp: 1209-1216Bradford, M.M.,197672248254Cai, X., J. Zhang, M. Chen, Y. Wu and X. Wang et al.,2011Shigella flexneri virulence.]]>2011Chopra, I., C. Schofield, M. Everett, A.O. Neill and K. Miller et al.,20088133139Clark, J.D., G.F. Gebhart, J.C. Gonder, M.E. Keeling and D.F. Kohn,1997384148Daskaleros, P.A. and S.M. Payne,1986Shigella flexneri sequences encoding congo red binding (crb): Conservation of multiple crb sequences and role of IS1 in loss of the Crb+ phenotype.]]>54435443Dinges, M.M., P.M. Orwin and P.M. Schlievert,2000Staphylococcus aureus.]]>131634Everest, P.,20072nd Edn.,pp: 1331-1331pp: 1331-1331Foster, T.J.,2005Staphylococci.]]>3948958Haider, K., A. Hossain, C. Wanke, F. Qadri, S. Ali and S. Nahar,1993Shigella to intestinal mucin.]]>118892Hale, T.L., E.V. Oaks and S.B. Formal,1985Shigella spp. and enteroinvasive Escherichia coli.]]>50620629Healy, B., S. Cooney, S. O'Brien, C. Iversen and P. Whyte et al.,2010Cronobacter (Enterobacter sakazakii): An opportunistic foodborne pathogen.]]>7339350Hong, H.A., R. Khaneja, N.M.K. Tam, A. Cazzato and S. Tan et al.,2009Bacillus subtilis isolated from the human gastrointestinal tract.]]>160134143Ishiguro, E.E., T. Ainsworth and W.W. Kay,1985Aeromonas salmonicida, detects the presence of the cell surface protein array involved in virulence.]]>16412331237Janda, J.M. and S.L. Abbott,199315912Kinney, K.K.,2010340209217Kulp, A. and M.J. Kuehn,201064163184Leive, L., V.K. Shovlin and S.E. Mergenhagen,1968Escherichia coli by ethylenediaminetetraacetate.]]>24363846391Magnusson, K.E.,1981333236Maurelli, A.T., B. Blackmon and R. Curtiss,1984Shigella flexneri 2a is correlated with loss of virulence and virulence-associated plasmid.]]>43397401Molnar, C., Z. Hevessy, F. Rozgonyi and C.G. Gemmell,1994Staphylococci in relation to adherence, hydrophobicity and toxin production in vitro.]]>47743748Murayama, S.Y., T. Sakai, S. Makino, T. Kurata, C. Sasakawa and M. Yoshikawa,1986Shigellae and enteroinvasive Escherichia coli.]]>51696698Ong, D.S., I.P. Jongerden, A.G. Buiting, M.A. Leverstein-van Hall, B. Speelberg, J. Kesecioglu and M.J. Bonten,2011Pseudomonas aeruginosa and Enterobacter species in intensive care units.]]>3924582463Parija, S.C.,2009Pages: 700Pages: 700Podschun, R. and U. Ullmann,1998Klebsiella spp. as nosocomial pathogens: Epidemiology, taxonomy, typing methods and pathogenicity factors.]]>11589603Proft, T. and E.N. Baker,200966613635Qadri, F., S.A. Hossain, I. Ciznar, K. Haider, A. Ljungh, T. Wadstrom and D.A. Sack,1988Shigella species.]]>2613431348Ray, C.G.,20105th Edn.,Sereny, B.,19574367376Smibert, R.M. and N.R. Krieg,19941994pp: 607-654pp: 607-654Tamma, P.D., S.E. Cosgrove and L.L. Maragakis,201225450470Thomas, S.R. and J.S. Elkinton,200485146151