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Dr. Kiran H S Assistant Proffessor Dept of Pathology. PYOGENIC INFECTIONS AND TYPHOID. ROUTES OF ENTRY AND DISSEMINATION OF MICROBES. Gram Negative and Positive Bacterial Infections. Staphylococcus aureus. Toxic Shock syndrome Scalded skin syndrome Bullous impetigo Food poisoning.
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Dr. Kiran H S Assistant Proffessor Dept of Pathology PYOGENIC INFECTIONS AND TYPHOID
Toxic Shock syndrome Scalded skin syndrome Bullous impetigo Food poisoning Toxin-Related Diseases Associated with Staph. aureus
Caused by any of several related toxic exotoxins produced by S. aureus • TSST-1 • most frequently implicated exotoxin • staphylococcal enterotoxin B is 2nd most frequently implicated • For illness to develop, an individual must be colonized or infected with a toxigenic strain of S. aureus and lack a protective level of antibody to the toxin Toxic Shock Syndrome
Menstruation most common setting for TSS • May also be associated with barrier contraceptives, puerperium, septic abortion, non-obstetric gynecologic surgery and skin lesions • chemical or thermal burns, insect bites, varicella lesions and surgical wounds • Overt infection with S. aureus is not required for the development of TSS Toxic Shock Syndrome
Fever > 102 0F • Rash; diffuse macular erythroderma • “sunburn rash” • Desquamation: 1-2 weeks after onset of illness typically on palms and soles • Hypotension; systolic blood pressure of < 90 mm Hg or orthostatic syncope • S. aureus infection or mucosal colonization Toxic Shock SyndromeDiagnostic Criteria
Involvement of at least three of the following organ systems • GI; vomiting or diarrhea • Muscular; severe myalgias or twice upper limit elevation of CK • Mucous membranes; hyperemia; vaginal, oropharyngeal, conjunctival • Renal; BUN or Creatinine level at least twice the upper limit of normal Toxic Shock SyndromeDiagnostic Criteria
Involvement of at least three of the following organ systems (ctd) • Hepatic; total serum bilirubin or ALT or AST level at least twice the upper limit of normal • Hematopoietic; thrombocytopenia • CNS; disorientation or alteration in consciousness Toxic Shock SyndromeDiagnostic Criteria
Wide spread skin disease due to epidermolytic toxin • Separation of epidermis at stratum granulosum • Children and immunocompromised adults • rare in immunocompetent adults because of the presence of antibodies • Begins with erythematous rash periorbital and perioral areas and spreads to the trunk and limbs generalized bulla formation Scalded Skin Syndrome
(+) Nikolsky sign • skin slides off when touched • Bullae usually sterile • effects are due to exotoxin • Prodrome of fever and malaise with generalized erythema and profound skin tenderness Scalded Skin Syndrome
Toxic Epidermal Necrolysis (TEN) • sloughing of the entire epidermis, resulting in very severe disease +/- death • usually immune mediated; drug associated (ampicillin, allopurinol) • less commonly assoc w/ Staph. • HIV infected patients Scalded Skin Syndrome
More localized & milder than scalded skin syndrome Young children Large friable clear to cloudy bulla honey yellow crusts (+) Nikolsky sign S. aureuscan be recovered from lesions 3) Bullous Impetigo
Due to preformed heat-stable enterotoxin produced in foods prior to ingestion Custard filled baked goods & processed meats More common in summer months Symptoms occur between 2-6 hours after ingestion of contaminated food Staphylococcal Food Poisoning
Symptoms begin abruptly • nausea, vomiting, crampy abdominal pain, and diarrhea • Self limited • Culture food, not patient Staphylococcal Food Poisoning
S. aureus the most common cause of osteomyelitis • Usually secondary to hematogenous spread to bone • less commonly due to trauma (open fx) or extension from adjacent infected tissue • Acute osteomyelitis may be cured by antibiotics alone • Chronic osteomyelitis requires surgical debridement of infected bone + antibiotics Staphylococcal Osteomyelitis
Bullous impetigo & scalded skin synd • Furuncles (boils) • deep infection of a single hair follicle • Carbuncles • deep infection of a group of contiguous hair follicles • Suppurative hidradenitis abscesses apocrine glands • Infection of the nail bed • Post-operative suture or wound abscess • Post-partum breast abscess Cutaneous Infections due to Staphylococcus aureus
Staph. aureus is the most common cause of acute infective endocarditis in IV drug abusers Infects normal and abnormal valves Involves tricuspid valve in 50% of cases Mortality is high inleft-sided (mitral) endocarditis andlowin right-sided (tricuspid or pulmonary) endocarditis Staph. aureus Endocarditis
Normal Aortic Valve(top) & Acute Bacterial Endocarditis in an IV Drug Abuser (below)
90% of hospital and community strains of S. aureus are resistant to penicillin due to production of -lactamase • MRSA (methicillin resistant S. aureus) • resistant to all beta-lactam antibiotics and to cephalosporins • treat with vancomycin RX of Staphylococcus aureus Infections
Vancomycin-resistant Staphylococcus aureus • Associated with transfer of resistance from enterococci • Treat with Synercid I.V. RX of Staphylococcus aureus Infections
Strep. pyogenes • most common cause of impetigo • Young children • Begins on face spreads to limbs • Erythematous macules vesicles & pustules honey colored crusts • Similar presentation as S. aureus • different from S. aureus • S. aureus; more likely to seebulla & + Nikolsky sign Streptococcal Impetigo
Highly contagious • avoid contact w/ other children • Topical antibiotics for localized infection • bacitracin, mupirocin • Systemic antibiotics for more generalized infection • penicillin, erythromycin, dicloxacillin Streptococcal Impetigo
Group A Beta-hemolytic • Most common cause of bacterial tonsillopharyngitis • Erythrogenic toxin • phage mediated • pyrogenic & cytotoxic • Also causes cellulitis, necrotizing fasciitis, streptococcal toxic shock syndrome, puerperal sepsis and endometritis Streptococcus pyogenes
PE; Temperature 39.4; pulse 120; respirations 12; BP 130/80. Extremities: erythematous right leg, swollen and tender Labs: WBC 21,000 (↑) with 80% neutrophils (↑)
Infection of the subcutaneous tissue • Etiology • most commonly Strep. pyogenes & Staph. aureus • traumatic disruption of skin • +/- spontaneously (without obvious disruption) in very young elderly or immunocompromised patients • Strep. pyogens produces hyaluronidase, liquefies tissue, more likely to have diffuse spread rather than abscess formation Cellulitis
Clinical • Area is acutely red, hot & tender/painful • leading edge is not raised but may be well defined • Rapid propagation centripetal from traumatic lesion • +/- lymphangitis lymphadenopathy • +/- desquamation of skin • Tx; Erythromycin, cephalosporins, amoxicillin/clavulanate, azithromycin, clarithromycin, clindamycin Streptococcal Cellulitis
Recurrent streptococcal leg cellulitis may occur in patients after coronary bypass surgery if the saphenous vein was removed Parenteral drug abusers have an increased risk of streptococcal cellulitis often associated with bacteremia, endocarditis, or septic thrombophlebitis Patients with impaired lymphatic drainage may have recurrent cellulitis Cellulitis of the foot or leg often co-exists with osteomyelitis in immunocompromised patients or diabetics Infectious Disease Pearls
Streptococcal Cellulitis surgical scar from vein stripping for coronary bypass