Bacterial

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 one or
  several skin layers.
• Skin Infections are associated with swelling
  ,tenderness, warm skin, blisters, ulceration,
  fever headache.. Rarely systemic
  disease..septicemia.
• Few Normal Bacteria Yeast species live in hair
  follicles- Skin .. may cause inflammation of Hair
  follicles .. folliculitis, Abscess formation (
  Boils)..

3
Type of Skin Infection-1

• Skin infection increased by presence of minor
  skin injuries, abrasions.. Increase production
  Androgenic Hormones after Puberty.. Increase
  activities Sebaceous ducts.. secretion Sebum
  (Fatty Acid Peptides) Increase keratin skin
  desquamation .
• Acne vulgaris is the most common skin disorder
  that affects more Jung male adults than
  females..Mostly face.. less other body parts due
  to accumulation of oil sebaceous glands dead
  tissues.
• Causative Agent Anaerobic Propionibacteria acnes
  , gramve small bacilli excrete Enzymes.. split
  sebum .. cause mild to severe forms inflammation.
  

4
Pityrosporum folliculitis is a condition where
the yeast invades hair follicles and causes an
itchy, Acne-like eruption caused by P.acne
5
Common Normal Skin Flora Pathogens

• Staphylococci, hemolytic Streptococci ( Group A)
  Micrococci, Propionibacteria , Acinetobacter
• Pityrosporum and other Yeasts..Candida species.
• S. aureus coagulaseve.. Various Enterotoxins
  enzymes( Coagulase, DNAse, hyaluronidase), skin
  infections is the most common important cause
  of human Skin diseases.
• About 15-40 per cent of healthy humans are
  healthy carriers of S. aureus ..nose or
  skin..feces.
• S.epidermidis is also common in skin..less
  virulent.. No toxins ..opportunistic pathogen..
• Clinical features commonly staphylococci
• Folliculitis / Furuncles .. Hair
  follicular-based papules and pustules..
  Erythematous lesions.. affect All ages.

6
Skin Infections
7
Staphylococci skin infections

• 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.
• S.aureus is more associated with serious skin
  infection due to release of 2 important
  toxins..not all strains
• 1-Toxic Schlock Syndrome TSST-1(Enterotoxin)
  Super antigens activate T-lymphocytes..Cytokines,
  caused by localized-systemic infection.. Rash
  Skin Desquamation may be associated with sepsis,
  high fever, multi-organ failure.. kidney
  failure.. can be fatal.

8

• 2-Scalded Skin Syndrome Epidermolytic/
  Exfoliative Toxins (A,B).. Minor skin lesion..
  Destruction skin intercellular connection.. Large
  blisters containing Fluid .. Skin scaling..
  Painful.. Common in small children.. Develop
  specific antitoxins..general massive inflammatory
  response.. rarely causes kidney failure ..Shock..
  Death without antibiotic treatment .
• 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 Diagnosis of staphylococcal infections should
  be confirmed by culture, gram-stain, positive
  cocci, ve catalase , coagulase test .
• Effective treatment For MRSA .. 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 underlying skin disease..Prevent repeat
  infection..No Vaccine available

10
Streptococcal Skin Infections-1

• Streptococcus pyogenes / B-H-Group A) ..Major
  virulence factors M-Protein, Hemolysin O S,
  Streptokinase (Fibrinolysin-digest Fibrin
  Proteins in Plasma), Streptodornase (DNAse)
  Erythrogenic-pyogenic exotoxins,Toxic Shock
  Syndrome toxin
• Cellulites/ Erysipelas Acute Rapidly Spreading
  Infection in skin Subcutaneous
  tissues..Following.. Wounds, Burns.. Highly
  Communicable..Massive Edema, Lymphatic's
  inflammation..Children. Impetigo Pyoderma
  Superficial Layers Skin.. Epidermis, Blisters,
  Children.. Highly Communicable..followed
  Streptococcus Sore Throat or rarely S. aureus
  wound infection.

11

• 2/
• Scarlet fever Following Group A Strept. Sore
  throat infection.. Erythematous skin rash due to
  release Erythrogenic Toxin.. Strawberry tong..
  small children.. permanent immunity
• Necrotizing fasciitis Few strains group A ,
  Minor trauma, Invasive infection, pyogenic
  exotoxins, Subcutaneous tissues Fascia, Rapid
  spread necrosis..Sever tissue damage..Pain,
  Fever, Sever systemic illness.. Fatal without
  Rapid Antibiotic Treatment
• Streptococcal Toxic Shock Syndrome pyrogenic
  toxin /superantigens/TSS, Infected Trauma,
  Bacteremia, Respiratory Multi Organ Failure..
  30 Death.

12
Skin rash - Scarlet Fever
13
B-H-Streptococci
14
Diagnosis Treatment

• Culture on blood, B-Hemolytic reaction, Gram-ve
  cocci in chain, catalase-ve, Bacitracin-Susceptibl
  e
• 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 Skin Infections

• N.gonorrhoea..Salmonella typhi or paratyphi..
  General Skin rash..Rosa spots
• Soft chancre /chancroid Haemophilus
  ducreyi..Gram-ve bacilli, STD.. Painful Skin
  Ulcer.. Extra Genitalia .. Common in Tropical
  Region.
• Syphilis Treponema pallidum.. Genital ulcers..
• Meningococemia N. meningitidis.. Sepsis, Skin
  rash hemorrhage..Thrombosis
• Rickettsia diseases Small intracellular bacteria
  human, R. prowazeki (Typhus), R. rickettsii
  (Spotted fever).. Transmitted by body lice..
  systemic diseases
• Pseudomonas aeruginosa Wound infections, Burns

16
/2

• Bacillus anthracis.. Cutaneous Black Lesions..
• Clostridium perfingens and other sp.
  Necrotizing Fasciitis.. Myonecrosis, Cellulitis,
  tissues putrefaction, gas production/ Gas
  gangrene.. Surgical/Traumatic wound.. Skin-
  Subcutaneous (Mixed Infection).. Specific Enzymes
  Exotoxins
• Borrelia Burgdorferi Lyme disease ..
  Transmitted by Tick/ Insect bites.. Incub. 1-3
  weeks.. Annular Rash.. Chronic Skin Lesion..
  Cardiac Neurological Abnormality.. Arthritis..
  Endemic USA, China, Japan
• Bartonella species G-ve bacilli Bartonellosis
  Cat Scratch Fever..followed Cat scratch or
  bite..Skin lesions.. Subacute regional
  lymphadenitis..Septicemia.

17
Tuberculosis-Leprosy-1

• Cutaneous Tuberculosis (TB).. Cutaneous TB is a
  relatively uncommon form of extra-pulmonary TB..
• Rare M. tuberculosis.. Common M.
  marinum-ulcerans.. Low Temperature..Water.. Skin
  Lesions.. Chronic cutaneous ulcer.. Small
  granulomas Follow skin injury..Trauma.
• Leprosy Chronic bacterial infection caused by
• M. leprae.. It primarily affects cold body
  sites skin, mucous membranes.. peripheral nerves
  ..nose, ears, eye lids and testes.
• characterized by multiple skin lesions
  accompanied first by sensation loss/ anesthesia..
  sensory loss in the affected areas, toes, finger
  tips, tissue destructions.

18
Leprosy-2
19
Leprosy-3

• 3/
• Lebrosy can affect people of all races around the
  world. However, it is most common in warm, wet
  areas in the tropics and subtropics.
• In most cases, it is spread through long-term
  contact with a person who has the disease but has
  not been treated.
• Most people will never develop the disease even
  if they are exposed to the bacteria.. have
• a natural immunity to leprosy.
• Worldwide prevalence is reported to be around 5.5
  million, with 80 of these cases found in 5
  countries India, Indonesia, Myanmar, Brazil and
  Nigeria.

20
Clinical Leprosy-4

• Infection incubation period range from 6 months -
  40 years or longer. usually begins in the
  extremities
• Leprosy forms depend on the person's immune
  response to the infection.
• There are several forms of leprosy
• Tuberculoid form.. Mild Form.. Few AF Bacilli,
  Lepromin skin test ve, Presence nerve sensation
• lepromatous type Severe form.. Numerous Acid-fast
  bacilli, Loss nerve sensation.. Lepromin skin
  test -ve

21
Diagnosis Treatment

• Lab Diagnosis A skin biopsy may show
  characteristic granulomas (mixed inflammatory
  cell infiltrate in the deeper layers of the skin,
  the dermis) with involvement of the nerves.
• Presence Acid fast bacilli.. number of bacilli
  visible depending on the type of leprosy.. No
  Culture.. No Protected Vaccine available.. BCG
  may help reduce the severity of disease
• Treatment Dapsone, Rifampin, Clofazimine.
  Life-long Treatment ..No Cure but Less Tissue
  Damage and Spread of Infection.

22
Common Fungal Skin Infection-1

• Superficial Cutaneous Mycosis Invade only dead
  tissues of the skin.. keratinized body tissues..
  Skin, Hair, Nails. causes skin peeling, redness,
  itching, burning.. less blisters and sores.
• Malnourishment, poor hygiene, suppressed immunity
  warm moist climate may increase the incidence
  fungal skin infection
• Dermatophytes Trichopyhton, Microsporum,
  Epidermatophyton spp., Yeast forms
  Piytrosporum, Trichosporons ..present in hair
  follicles skin folding.
• Transmission Usually from person to person or
  animal to person.. dust particles..common more
  with chronic skin disorders.

23
Tinea Corporis
24
Tinea pedis -Tinea capitis kerion
25
Skin Fungal Infection-2

• Tinea capitis Hair follicles, scalp circular
  patches.. Scaling, Hair Loss..Children..Rare
  adults
• Tinea corporis Skin annular-erythematic lesions,
  Vesicles, Scaling.. Itching.. Rash.. All Ages..
  Mostly caused by Dermatophytes ..rarely mixed
  with Yeast
• Tinea pedis Red vesicles.. Interdigital spaces,
  web lesions, Toes, Plantar surface.. Feet,
  Itching.. Chronic lesions..Wearing tight
  shoes/socks, increased feet sweating.. More in
  Adults than children.. Cased by all
  Dermatophytes.
• Tinea cruris Pelvic area.. Groin.. Erythematic
  Lesions, Itching, Chronic.. more common in male
  young adults..mostly Epidermophyton spp

26
Skin Fungal Infection-3

• Tina unguium (Onychomycosis) Mostly caused by
  Trichophyton ,Microsporum.. less
  Candida..fingernails toenails. Nails become
  colorless/dark colored, thicken, disfigure and
  brittle..Diabetes
• Psoriasis is a common skin disorder produces
  thick red plaques covered with silvery
  scales..can affect the nails, scalp, skin and
  joints..not caused by fungus and not transmitted
  to others.
• Eczema develops due to multiple immunological
  other medical conditions.. Skin becomes inflamed
  or irritated..No infectious agent involved.
• Aspergillus Cryptococcus spp. Rare cause
  localised skin or nail..

27
Onychomycosis-Psoriasis
28
Skin Fungal Infection-3

• Tinea Versicolor/Pityriasis Malassezia furfur /
  Piytrosporum folliculitis.. Lipophilic Yeast
  ..difficult to culture in Labs. Part skin flora..
  Endogenous infection.. Skin Moist-Folded Area..
  Discoloration.. Red Spots.. Mostly Face-Neck
  Finger Trunk..Mild..rarely Chronic, Stress
  conditions, UV-Light, Common in young adults.
• Head dundruff, Seborrheic dermatitis.
• White Black Piedra..Trichosporon spp., Soft to
  hard nodules. scalp hair hair shaft , skin face
  , any body part.

29
Yeat skin infection

• Candidasis C. albicans, C. glabrata, C.
  tropicalis.. Other spp. Endogenous
  infection..moist folds of skin.. Lesions, finger
  nails, toenails, Finger webs.. Diabetes,
  immuno-compromessed.. more common in Infant
  women.. Candida infections can look just like
  other types of dermatitis /eczema or skin
  allergy. itching, redness..infection
• Blasmycosis Blastomyces dermatitidis
  Histoplasmosis Histoplasma capsulatum..
  Dimorphic Fungi.. Soil ..Spore Inhalation..
  Respiratory infection.. Systemic Infection..
  Complications Skin ulcerations/lesions
  Granulomas..causes severe damages..common USA,
  Canada

30
Tinea Pityrisis / versicolor Seborrheic
dermatitis
31
Lab diagnosis-4

• Direct microscopic examination of skin scales
  dissolved in a 10 solution potassium hydroxide
  (KOH).. demonstrating the fungus as small
  Filaments / Yeast like structures.
• Culture Sabouraud Dextrose agar, Incubation at
  room temperature 37 C for 2-6 Weeks. . Slow
  growth for Dermatophytes..Rapid growth Candida.
• ChromCandida agar.. used for rapid identification
  of common Candida species.
• Treatment Most skin infections respond very well
  to topical antifungal drugs..Less systemic drug
  .. interact with Ergosterol ..causing Fungal Cell
  membrane disruption.. Imidazole drugs
  ..miconazole, clotrimazole, econazole,
  ketoconazole, fluconazole