Role of Staphylococcus aureus in Atopic Dermatitis

Abstract

xiiixiv Chapter one: Introduction 01-06 1.1 Research problem 02-05 1.2 Objectives 06 Chapter two: Literature review 07-33 2.1 What is atopic dermatitis? 08 2.2 Prevalence of atopic dermatitis 09 2.3 Diagnosis of atopic dermatitis io 2.4 Pathogenesis and etiology of atopic dermatitis 11-27 2.4.1 Epidermal barrier defects in atopic dermatitis 11-16 2.4.2 Immune responses in atopic dermatitis 17-22 2.4.3 Genetic susceptibility in atopic dermatitis 23-25 2.4.4 Provocation factors 26-27 2.5 Staphylococcus aureus as a provocation factor 28-35 2.5.1 Staphylococcus aureus colonization in atopic 28-29 dermatitis 2.5.2 Role of Staphylococcus aureus superantigens 30-35 Chapter three: Methodology 36-52 3.1 Subjects 37 3.2 Preparation of culture media 37-38 3.3 Sample collection and processing 38 3.4 Identification of Staphylococcus aureus 39-40 3.4.1 Gram staining 39 3.4.2•Catalase test 40 3.4.3 Coagulase slide test 40 3.4.4 Coagulase tube test 40 3.5 Antibiotic sensitivity testing-42 3.6 Detection of J3-lactamase enzyme production 43 3.7 Extraction of bacterial DNA-45 3.7.1 Preparation of enzymatic lysis buffer-44 3.7.2 Harvesting bacterial cells for DNA extraction 44 3.7.3 Lysis of bacterial cells and DNA extraction 45 3.8 Detection of toxin genes by polymerase chain reaction-52 3.8.1 Detection of Panton-Valentine leukocidin gene in-47 Methicillin resistant Staphylococcus aureus 3.8.2 Detection of Staphylococcal superantigenic toxin genes 47-52 3.9 Statistical analysis 52 Chapter four: Results 53-84 4.1 Characteristics of the participants 54 4.2 Staphylococcus aureus colonization patterns 55-60 4.3 Staphylococcus aureus colonization densities 60 4.4 Antibiotic sensitivity patterns of Staphylococcus aureus 61-65 isolates 4.5 Polymerase chain reaction (PCR) results for toxin genes 66-84 4.5.1 PCR results for Panton-Valentjne leukocidin (PVL) 66 gene in Methicillin resistant Staphylococcus aureus (MRSA) 4.5.2 PCR results for Superantigenic toxin genes in-84 Staphylococcus aureus Chapter five: Discussion-91 5.1 Staphylococcus aureus colonization patterns-87 5.2 Antibiotic sensitivity patterns of the isolates-88 5.3 Superantigen profile of the isolates-91 'It Chapter Six: Conclusions, limitations, benefit to the society and future 92-96 directions 6.1 Conclusions 93-94 6.2 Limitations of the study 94 6.3 Benefit to the society 95 6.4 Future directions 96 List of figures No Description Page 2.1 Atopic dermatitis lesions; A-Acute early onset lesion, B-chronic 08 lichenified lesion 2.2 General structure of the epidermis 12 2.3 Increased serine protease activity in atopic dermatitis 13 2.4 Normal and disrupted stratum corneum 15 2.5 An amplification cycle of atopic skin inflammation 17 2.6 Binding of superantigen and conventional antigen with majour 31 histocompatibility complex (MI-IC) class II and T cell receptor 3.1 Stokes method for antibiotic susceptibility testing 4.1 Skin and nasal colonization of Staphylococcus aureus in different age groups of atopic dermatitis patients 4.2 Skin and nasal colonization of Staphylococcus aur...