STAPHYLOCOCCAL INFECTIONS

1. STAPHYLOCOCCAL INFECTIONS Bacterial invasion Distant diseases( SSSS-TSS) Toxin induced( food intoxication)

2. MICROBIOLOGY: non motile, facultative anaerobes

3. EPIDEMIOLOGY Normal flora: Ant. Nares Skin( damaged) Vagina Axilla Perineum Oropharynx Persistant/ Transient colonization: 25-50% higher in: Insulin dependent diabetics HIV+ IVDU Hemodialysis Skin damaged

4. Infection: Personal colonization Other people( hand of hospital personnel) Environment Aerosol of respiratory/nasal secretion S.Aureus: leading cause of nosocomial infection CoNS: leading cause of primary bacteremia MRSA in community: prisoners athletes Drug users ( poor hygiene, close contact, contaminated material, damaged skin)

5. PATHOGENESIS Inoculation and local colonization Invasion Evasion of host defense mechanisms spreading

6. 1- Inoculation and local colonization Colonization in keratinized epithelium and mucin: - other resident normal flora - nasal mucosal damage - antimicrobial properties of nasal secretions - host genetic factors (HLA) - S.aureus( fibronectin binding protein, clumping factor, collagen binding protein), S,coagulase neg ( biofilm) Inoculation: - minor abration - administration of medication - intravascular access with catheters

7. 2- Invasion Enzyme: Serine proteases Hyaluronidases destruction of host�s tissue Thermoneucleases nutritional material Lipases Toxin: 1- cytotoxins:-Panton-Valentine Leukocidin (cytolytic effect on PMN, Mac, Mono.): skin, lung infection � VRSA in community - a toxin ( pore formation in eukaryotic cells) 2- pyrogenic toxins: ( superantigen) TSS-1, enterotoxin 3- exfoliative toxins: ETA, ETB ( destroy desmosomes) Cell wall: N-acetyl muramic acid N-acetyl glucosamine inflammatory process Lipoteichoic acid

8. 3- Evasion of host defense mechanisms Polysaccharide capsule: Antiphagocytic polysaccharide microcapsule) Protein A: FC portion of IgG so inhibit opsonophagoytosis of PMN Intracellular: protection from immune system small-colony variant(prolongred ab use, slow growing, chronic/recurrent infection, prolonged ab treatment) 4- Spreading

9. Groups at increased risk of infection Diabetes: - colonization - impaired leukocyte function PMN defects: - neutropenia - intracellular killing (CGD) - chemotaxis ( Job�s syn., Chediak-Higashi syn.) - phagocytosis( Wiskot-Aldrich syn., Down syn.) - opsonization ( combined/selective hypogamaglobulinemia) Skin abnormality: Eczema Prosthetic devices

10. DIAGNOSIS Smear: cocci g+, single, pairs, cluster Culture Blood culture PCR

11. CLINICAL SYNDROMES Skin/ Soft tissue infections skin dis. Damaged skin Injection Poor personal hygiene Folliulitis: Furucles: Carbuncles: Mastitis: Impetigo: Cellulitis: Hydradenitis suppurative: Surgical wound infection:

12. Skin Infection 1- Folliculitis -Involve hair follicle -Central area of purulence -Surrounding induration and erythema

13. Skin Infection 2-Furuncles (boil) painful Hairy, moist region Central purulence

14. Skin Infection 3- Carbuncle Lower neck Severe/ painful Extend to deeper layer Pus discharge

15. Skin Infection 4- Mastitis 1-3% of nursing mothers 2-3 w after delivery Cellulitis to abscess Systemic sign

16. Skin Infection 5- Surgical wound infection Progressive edema, erythema, pain

17. Skin Infection 6- Hidradenitis suppurativa Apocrine sweat gland Crops of furuncles axillary., perineal, genital area Spontaneous drainage Hypertrophic scar

18. Skin Infection 7- Cellulitis Pain, erythema, warmness

19. Musculoskeletal infections Osteomyelitis: 1-Hematogenous: Child: long bone, fever, bone pain, claudicating, ESR, CRP, B/C (50%), bone biopsy, X-ray, Tc-phosphate, MRI Adult: ( endocarditis, diabetes, IVDU, hemodialysis) vertebral, fever, back pain, epidural abscess, MRI 2-Contiguous: drainage, no healing, fistula, exposed bone, bone culture and biopsy Arthritis: fever, swelling, pain, aspiration (>50,000 PMN, cluster g+cocci) Pyomyositis: skeletal muscle, tropical region, trauma, fever, swelling, pain, aspiration (pus, WBC, cluster g+ cocci)

20. Respiratory tract Newborn/infant: shortness of breath, fever, respiratory failure, CXR ( pneumatoceles), pneumotorax, empyema Adult: nosocomial: fever, increased sputum, new infiltration community-acquired: postviral( Influenza), septic pulmonary emboli( IVDU)

21. Bacteremia Sepsis Endocarditis Vasculitis Metastatic seeding: bones, joints, kidney, lungs High risk: community-acquried( except IVDI) no primary source Prosthetic device

22. Endocarditis Increased recently: IV device IVDU hemodialysis immunosuppression New/changing cardiac valvular murmur, cutaneous evidence ( Osler�s node, Janeway lesion, embolic diseases) Dignosis: B/C, Transtoracic/ transosophageal echocardiography

23. Clinical setting Right-sided (IVDU): fever, toxic clinical appearance, pleuretic chest pain, production of purulent( bloody) sputum, CXR (septic emboli) Left-sided native valve: damaged valve Prosthetic-valve: valvular insuifficency, myocardial abscess, need valvular replacement Nosocomial

24. UTI Ascending: instrumentation Hematogen

25. Prosthetic device IV catheter Prosthetic valve Orthopedic device Peritoneal catheter Intraventricular catheter Vascular graft Left-ventricular-assist device - acute, progressive, pyogenic collection, early postimplantation

26. Toxic-mediated diseases A:Toxic shock syndrome: - menstrual (TSS-1) - nonmenstrual (Enterotoxin) 1-fever (T>38.9) 2- hypotension (BP<90mmHg, orthostatic hypotension) 3- diffuse macular rash with desquamation in 1-2 w 4- multisystem involvement: a) hepatic( Bil, ALT, AST>2X) b) hematologic( plat.< 100,000) c) renal ( BUN, Cr> 2X) d) mucous( vaginal, oropharyngeal, conjunctival hyperemia) e) GI (vomiting, diarrhea) f) muscular ( severe myalgia, CPK>2X) g) CNS ( disorientation, alteration in conciousness without focal neurologic sign) 5- neg. serology for measles, leptospirosis, RMSF, �.

27. B:Food poisoning Toxin resistant to heat 1-6h after ingestion Nausea, vomiting, diarhea Recovery in 8-10h D: detection of bacteria/ toxin in food R: supportive

28. C: Staphylococcal Scalded-Skin Syndrome( Ritter�s disease) Newborn/ child<1y Nasal carriage of staff Localized infection and toxin production Fragile/ tender skin, thin-walled fluid-filled bullae, Nikolsky�s sign, fever, lethargy, irritability with poor feeding, dehydration Without mucous membrane involvement

29. COAGULASE-NEGATIVE STAPHYLOCOCCUS (CoNS) S. Epidermidis: normal flora of skin, oropharynx, vagina 1-Implanted prosthetic material: coated with fibronectin/ fibrinogen 2-Surface-associated staphylococcal enzyme: autolyzin, fibrinogen-binding protein, cell wall teichoic acid 3-Extracellular polysaccharide (slime): protective biofilm Prosthetic cardiac valve, prosthetic joint, vascular graft, intravascular device, CNS shunt infection S. Saprophyticus: UTI in young women D: culture ( 10-25% true bacteremia) 1- frequent isolation of 1 species from different site 2- growth <48h 3- growth in aerobic/ anaerobic media

30. TREATMENT Antimicrobial agent Surgical incision and drainage Removal of device Prolonged therapy (4-8w) 1- immunocompetent 2- primary focus that was removed 2w

31. Antibiotics Penicillin: ( P.G. 4mu/4h, Naficillin2g/4h, Oxacillin 2g/4h) < 5% - Penicillinase Methicillin: (PRP)( naficillin/Oxacillin, Cefazolin, Vancomycin, Imipenem) - Penicillin binding protein 2 a Vancomycin: ( MRSA), ( TMP-SMX, Ciprofloxacin, Levofloxacin, Quinupristin/dalfopristin, Linezolid, Daptomycin ) 40-50% - Abnormal cell wall Intermediate/ complete resistant to vancomycin ( VISA/VRSA) Empirical : ( Vancomycin)

32. Synergistic effect ?-lactam + aminoglicoside Vancomycin + Gentamycin Vancomycin + Gentamycin + Rifampin Vancomycin + Rifampin

33. Endocarditis: native-valve: PRP + Aminoglicoside 4-6w Prosthetic-valve: PRP + Aminoglicoside + Rifampin + surgery Osteomyelitis/ arthritis: 4-6w chronic: surgical debridement joint: repeated aspiration prosthetic joint: Ciprofloxacin + Rifampin TSS: Fluid + Pressors + PRP + Clindamycin+ IVIG SSSS: supportive + PRP

34. PREVENTION Hand washing Isolation procedures Topical antibiotic agents: muciprocin Vaccine: - capsular polysaccharide protein - Ligand-binding domain of MSCRAMMS

35. Streptococcal infections Normal human flora: respiratory, GI, GU G+cocci in chains Facultative anaerobe/strict anaerobe Classification: �-hemolysis: Lancefield group A, B, C, G a-hemolysis: Pneumococci Viridance ?-hemolytic Enterococcal: Faecalis, Faecum

38. Pharyngitis Respiratory droplet, food-borne 20-40% exudative pharyngitis in children. Rare under 3 y. fever, malaise, without exudative pharyngitis Incubation period: 1-4d Sore throat, fever, chills, malaise, abdominal pain, vomiting, erythema and swelling of pharyngeal mucosa, purulent exudates, enlarged tender ant. cervical LAP Throat culture, Rapid test ( latex, ELISA) (specificity>90%, sensitivity<55-90%) P.B. 1.2mu IM, P.V. 250mg/ tds 10d Erythromycin, Azithromycin

39. Complications Suppurative Cervical lymphadenitis Peritonsillar/retropharyngeal abscess Sinusitis Otitis media Meningitis Bacteremia Endocarditis Pneumonia Nonsuppurative ARF(throat infection, preventable with ab) PSGN(throat and skin infection, unpreventable)

40. Asymptomatic carrier state (20%) Bacteriologic treatment failure If it is a potential source of infection to others Pharyngeal colonization: P.V. 500mg/6h 10d + Rif 600mg/12h 4d Rectal colonization: Vanco. 250mg/6h po+ Rif 600mg/12h 10d

41. Scarlet fever Strep.pyrogenic exotoxic A,B,C Pharyngitis Rash: 1-2 d, upper trunk, extremities ( exept palms and soles), sandpaper Circumoral pallor Strawberry tongue Pastia�s lines 6-9d desquamation

42. Impetigo Strep.A/ S.aureus Young children Warm months Tropical climate Poor hygiene Face, legs Red papule, vesicle, pustule, honey-comb crust, thick No fever, no pain Treatment: same as pharyngitis cephalexin, cloxacillin 250mg/6h mupirocin Complication: glomerulonephritis

43. Erysipelas Strep. A, C, G Bright red skin, sharply demarcated Warm, tender, shiny, swollen 2-3d superficial bullae Fever, chills Molar area of face, lower extremities

44. Cellulitis Disruption in lymphatic drainage: cellulitis, mastectomy, DVT, chronic lymphedema, CAB G Fissure, tinea pedis, surgical wound (24h) lymphangitis Treatment: P.