Bacterial & Fungal skin, Soft Tissue & Muscle infections

1. Bacterial & Fungal skin, Soft Tissue & Muscle infections For Second Year Medical Students Prof. Dr Asem Shehabi

2. Infections of Skin & Soft Tissues • Infections depends upon the Layers of Skin & Soft Tissues involved ( epidermis, dermis, subcutis, muscle).. Infections may involve several layers. • Skin Infections are associated with: swelling ,tenderness, warm skin, blisters, ulceration, fever headache.. Rare Systemic disease. • Few Normal Bacteria & Yeast live in hair follicles.. Skin .. maycause inflammation of Hair follicles ..folliculitis, Abscess formation ( Boils)..

3. Skin Infections

4. Type of Skin Infection • Skin infection increased .. production Androgenic Hormones.. Puberty… Increase activities Sebaceous ducts..IncreaseSebum (Fatty Acid+ Peptides)… Increase keratin & presence of desquamation … • AnaerobicPropionibacteria acnes ( gram+ve small bacilli) & Staph spp. excrete Enzymes.. SplittingSebum ..cause inflammation ..develop Acne vulgaris • Certain Systemic Infectionmay cause skin infection ..N. meningitidis (Haemorrhagic Lesions) Salmonella typhi ( skin Rash, Rose spots), Treponempallidum ..Syphilis.. Pseudomonas aeruginosa.. Rash

5. Acne

6. Common Normal Skin Flora & Pathogens • Staphylococci, hemolytic Streptococci (Group A) Micrococci, Propionibacteria , Acinetobacter , Pityrosporum (Yeasts) • S. aureus(coagulase+ve) is the most common & important cause of human Skin diseases.. Various Enterotoxins & Enzymes..Coagulase, DNAse, Hemolysins , Hayluronidase . • About 15-40 per cent of healthy humans are healthy carriers of S. aureusintheir nose or skin.. Infants carry S. aureus in feces • Common Clinical skin features S.aureus • Folliculitis / Furuncles.. Hair follicular-based papules and pustules.. Erythematous lesions.. affectAll ages.

7. -Impetigo:Epidermis, Crusted lesions..Skin sores..face and extremities.. CommonYoung children -Toxic Schlock Syndrome:Systemic Infection..high fever,Rash & Skin Desquamation due to Release Toxic Shock Syndrome Toxin-1 (TSST-1 ).. Super- antigens toxin.. Activate T-lymphocytes.. Release Cytokines.. General massive inflammatory response, hypotension, Shock, Comma.. Vomiting, diarrhea multiple organ failure.. Hepatic inflammation, kidney failure, Death.. Commonchildren > five years old, menstruated Women. - Scalded Skin Syndrome:Exfoliative A,B Toxins.. Minor Skin Lesion.. Destruction Skin Intercellular Connection .. Large Blisters Containing Fluid .. Skin Scaling.. Painful.. Common Babies

8. - Methicillin Resistant S. aureus • S. epidermidis.. normal inhabitants of the skin surface.. but Less Pathogenic. Most its infections occur in normal individuals.. Dry Skin.. Injury.. but underlying illness increase the risk of infection.. Infants.. compromised patients • Staphylococci are becoming increasingly resistant to many commonly used antibiotics including: Penicillins-Cephalospoins.. Methicillin & flucloxacillin , Augmentin (amoxycillin + clavulonic acid) .. B-lactamase-resistant penicillins.. Other antibiotics • Worldwide Spread Methicillin resistance (MRSA).. 20-90% ..in Jordan about 60% clinical isolates (2004)

9. Diagnosis &Treatment of staphylococcal infections • Lab Diagnosisof staphylococcal infections should be confirmed by: culture, gram-stain positive cocci, +vecatalase , coagulase test . • Effective treatment ForMRSA .. Vancomycin, Teicoplanin, Imipenem, Fusidic acid • Drainage of pus collections before treatment • Surgical removal (debridement) of dead tissue (necrosis) • Removal of foreign bodies (stitches) that may be a focus of persisting infection • Treating the underlying skin disease

10. Streptococcal Skin Infections-1 • Streptococcus pypgenes/ B-H-Group A) ..Major virulence factors: M-Protein .. Hemolysin O & S, Pyrogenicexotoxins -Erythrogenic toxin .. Causing Scarlet fever + Toxic Shock Syndrome, Hayluronidase , Streptokinase (Fibrinolysin- digest Fibrin & Proteins in Plasma), Streptodornase (DNA) • Cellulites : Acute Rapidly Spreading Infection in Skin & Subcutaneous Tissues.. Following.. Wounds, Burns.. Highly Communicable • Erysipelas : Massive Brawny Edema.. Dermis.. Children • Impetigo: Pyoderma Superficial Layers Skin.. Epidermis, Blisters, Children.. Highly Communicable.. Following Streptococcus Sore Throat

11. B-H-Streptococci

12. /2 - Necrotizing fasciitis : Following wound infection.. Subcutaneous Tissues & Fascia, Rapid Spread Necrosis.. Tissue Liquidation.. Fatal without Rapid Antibiotic Treatment -Scarlet fever: Following Group A Strept. Infection..Erythematous Rash due toErythrogenic Toxin.. Children - Streptococcal Toxic Shock Syndrome:PyrogenicExotoxin A.. Invasive Group A, Infected Trauma .. Bacteremia, Respiratory & Multi Organ Failure, 30% Death • Allergic hypersensitivity ..ErythemaNodosum.. Vasculitis

13. Skin rash - Scarlet Fever

14. Diagnosis & Treatment • Culture on blood, B-Hemolytic reaction, Gram-+vecocci in chain, catalase-ve, Bacitracin-Susceptible • Serotyping should used to confirm group of streptococcal infection.. A, B, C etc. using antisera against group-specific cell wall carbohydrate –Antigens (Lancefield classification) • Penicillin is the drug of choice.. All Group A streptococci are very sensitive to penicillin. • Patients with penicillin allergy may be given Erythromycin.. Azithromycin..

15. Less Common Bacterial associated with Skin Infections • Gonorrhea: Neisseriagonorrhoea.. Skin rash • Soft chancre /chancroid: Haemophilusducreyi.. STD.. Painful Skin Ulcer, Extra Genitalia, Tropical countries • Syphilis: Treponemapallidum.. Genital ulcers.. • Meningococemia : N. meningitidis.. Skin rash & hemorrhage .. Thrombosis • Rickettsia diseases: human lices.. Transmit R. prowazeki (Typhus), R. rickettsii (Spotted fever).. • Pseudomonas aeruginosa: Wound infections, Burns skin follicultis