ABSTRACT
AIMS: To characterize the interaction between cell surface carbohydrates and Staphylococcus aureus. METHODS AND RESULTS: In the present study, in vitro adherence of S. aureus to Detroit 562 cells, amount of cell surface desialylation and effect of subterminal monosaccharides on desialylated glycoproteins on adherence was studied with colony counting, HPLC, fluorescence microscopy and fluorometric techniques. According to our findings, S. aureus adherence to pharynx cells was enhanced (40%) after neuraminidase treatment, and neuraminidase also cleave great amount of Detroit 562 cells surface sialic acid (39-60%). Adherence assay with various monosaccharides-pretreated bacteria, and lectin competitive inhibition, showed that the residual subterminal galactose, fucose and N-acetyl-D-glucosamine remaining on desialylated Detroit 562 cell surface glycoproteins responsible for this binding. CONCLUSION: The results are the first to show that galactose, fucose and N-acetyl-D-glucosamine remaining on desialylated pharynx cell surface glycoproteins serve as the adhesine receptors for S. aureus. SIGNIFICANCE AND IMPACT OF THE STUDY: This study may explain the predisposition of severe S. aureus pneumonia complication in respiratory viral infections.
Subject(s)
Bacterial Adhesion/physiology , Membrane Glycoproteins/metabolism , Staphylococcus aureus/metabolism , Adhesins, Bacterial/metabolism , Bacterial Adhesion/drug effects , Epithelial Cells/metabolism , Epithelial Cells/microbiology , Lectins/metabolism , Monosaccharides/pharmacology , N-Acetylneuraminic Acid/metabolism , Neuraminidase/metabolism , Neuraminidase/pharmacology , Pharynx/cytologyABSTRACT
AIMS: Foot infections and their sequelae are among the most common and severe complications of diabetes mellitus. As diabetic patients with foot infections develop osteomyelitis and may progress to amputation, early diagnosis of osteomyelitis is critical. METHODS: We compared the diagnostic values of labelled leucocyte scanning with Tc(99)m, magnetic resonance imaging (MRI) and microbiological examination of bone tissue specimens with histopathology, the definitive diagnostic procedure. Thirty-one diabetic patients with foot lesions were enrolled in the study and histopathological examination was performed in all. Patients had clinically suspected foot lesions of > or = grade 3 according to the classification of Wagner. RESULTS: Bone specimens were obtained for histopathological examination. Microbiology had a sensitivity of 92% and specificity of 60%. Labelled leucocyte scanning had a sensitivity of 91%, specificity of 67%, and MRI a sensitivity of 78%, specificity of 60%. CONCLUSIONS: Microbiological examination may be as useful as and less costly than other diagnostic procedures and is the only method which can guide the choice of antibiotic therapy.