Chapter 63 Wound Infections

Disease	Etiologic Agent	Pathogenesis & Transmission	Symptoms	Lab Tests	Prevention and treatment
Bacterial Skin & Wound Infections
Staphylococcal Wound Infections Scalded Skin Syndrome	Staphylococcus aureus	pyogenic - pus interferes with antibiotics,fibrin- binding proteins, coagulase, antigens	inflammation, necrosis	GPC cl, catalase +, coagulase +, MSA + Watch for MRSA	clean wound, topical antibiotics
Streptococcal Wound infections Flesh eating Strep Impetigo Necrotizing fasciitis	Streptococcus pyogenes	Wounds, occasionally no trauma bacteria binds to fibrin toxin - superantigens exotoxin A -> shock, exotoxin B destroys tissue	inflammation, necrosis, extremely rapid and deep tissue destruction	GPC ch, catalase -, β hemolytic p 299	Common preventative measures handwashing, early detection of strains, amputation, penicillin (increasing erythro resistance)
Pseudomonal infections	Pseudomonas aeruginosa GNR	pools, hot tubs,dirt, injectable drugs, IV bottles, burns - opportunist, toxin, prevents healing, endotoxic shock	adhesion, toxin, pseudomembrane	oxidase +, non-fermenting GNR, highly resistant, distinctive odor, hemolysis, pigmentation p385	highly resistant to antibiotics and disinfectants, wound care-silver sulfadiazine
Acne	Propionibacterium acne	opportunistic	abscesses or pustules	p535	Penicillins
Folliculitis	Staph. aureus, Enterobacteriaceae, Pseudomonas aeruginosa	opportunistic infection around the hair follicle, predisposed through clothes rubbing or blockage of follicle	swelling, pain, redness, pus	symptoms indistinguishable, must be determined by identification and sensitivity
Lyme disease	Borrelia burgdorferi Spirochete	Introduced through tick bite, enters blood Spreads quickly, depresses immune system 2^nd stage = immune response 3^rd stage autoimmunity?	1) Localized - Skin with Bull’s eye rash – chills, fever, pains 2) Disseminated – blood, joints, brain 3) Chronic – CNS	Poor culture IFA, ELISA	Insect protection; bug spray, long clothes, ampicillin, ceftriaxone

Disease	Etiologic Agent	Pathogenesis & Transmission	Symptoms	Lab Tests	Prevention and treatment
Anaerobic Bacterial Wound Infections
Tetanus (Lockjaw)	Clostridium tetani endospore forming GPR anaerobe	ubiquitous endospores found in soil, puncture wounds, tatoo, IV drug use, insects infection not invasive, toxin (tetanospasmin) spread in blood	anaerobic wound infection,sustained muscle contractions, lockjaw, extreme pain, 2°lung infection	anaerobic culture, endospore identification 511-535	vaccination with toxoid. antitoxin (TIG), debridement, flagyl (endospores survive antibiotics)
Gas Gangrene	Clostridium perfringens endospore forming GPR anaerobe	ubiquitous endospores found in soil,requires specific conditions common in war α-toxin (attacks cell membranes), collagenase, hyaluronidase	anaerobic wound, abrupt onset, pain, swelling, necrosis, foul smelling gas production	"" ""	no toxoid or vaccine, wound care is essential, hyperbaric treatment & antibiotics
Disease	Etiologic Agent	Pathogenesis & Transmission	Symptoms	Lab Tests	Prevention and treatment
Bacterial Bite Wounds
Animal Bites	Pasteurella multocida GNR (coccobacillus)	animal bite - dogs, cats, monkeys adhesins, capsule, production of abscesses	pain, inflammation, redness		clean wound, antibiotics amoxocillin
Cat Scratch	Bartonella henselae GNR curved	bites and scratches cat to cat by fleas 10% progress to septicemia and heart valve involvement or encephalits and death	scratch or bite, pimple, lymph node swelling		clean wound, antibiotics ampicillin
Human Bites	anaerobes, strep., S. aureus	collagenase, hyaluronidase, ribonuclease, proteinases, anti-complement (polymicrobic synergistic effect)	swelling and pain, pus, and lymph node involvement		clean wound, synergistic including anaerobic antibiotics
Disease	Etiologic Agent	Pathogenesis & Transmission	Symptoms	Lab Tests	Prevention and treatment
Fungal Wound Infections
Sporotrichosis	Sporothrix schenckii	puncture wounds-does not become involved with a normal immune status	wound, ulcer, lymph node involvement		gloves Itraconazole
Tinea or Ringworm	Dermatophytes Epidermophyton, Trichophyton, Microsporum	Contact, moist warm environments Invade nails, hair, skin (keratin)	May begin with papules, Dry red cracked skin		Antifungals – topical treatment, environmental controls; nails hardest to treat
Candida	Candida albicans	Moist skin areas, under diapers, skin folds	Red papules to red rash		OTC, nystatin, Increased incidence in Diabetics & obesity

Disease	Etiologic Agent	Pathogenesis & Transmission	Symptoms	Lab Tests	Prevention and Treatment
Viral Infections of the Skin
Chickenpox (disseminated) Varicella –Zoster Shingles (limited to nerves)	Herpes virus dsDNA With latent tendencies	Air and contact Inhaled, invades mucosa, spreads through blood & lymph nodes	Erupting lesions , itchy, papules-vesicles 2° bacterial infections & scarring		Vaccination Isolation, no general treatment, IgG for serious cases (pregnancy and neonatal infections serious)
Measles Rubeola – red or hard measles	Paramyxovirus ssRNA enveloped	Inhaled, invades mucosa, spreads through blood & lymph nodes, destroys respiratory membrane	Cold-like symptoms, rash moving from extremities in, Koplik’s on tongue, 2° bacterial infections- pneumonia, otitis, encephalitis, SSPE		Vaccination MMR, no general treatment, (miscarriage potential no defects) Mortality – 1-2/1000
Measles Rubella – German Measles	Togavirus ssRNA	Inhaled, invades mucosa, spreads through blood & lymph nodes (40% asymptomatic contributing to spread)	Mild disease with light rash from moving from center out		Vaccination MMR, no general treatment, (congenital rubella = fetal cells infected chromosome damage defects in heart, brain, eyes, ears)
Other common rashes Fifths – Parvovirus; Roseola – Herpes 6
Warts –	Papilloma virus - dsDNA	Contact through broken skin, virus survives on fomites Invades epithelium and transforms cells – genital warts & Cervical cancer	Benign tumor on skin, plantar = deeper invasion		Treatment by removing abnormal cells – surgery freezing, chemotherapy; self-resolution in 2 years

Parasitic Infections of Skin
Dracunculiasis Guinea Worm Fiery Serpent	Dracunculus medinesis	Contaminated Water exposureWorm larvae enters through skin from contaminated water	Itching growth beneath skin; immune response causes		Control intermediate host, Physical removal,

Chapter 63 Skin, Wound, & Soft Tissue Infections