[MICRO 20] LEC 12 - Microbial Skin Infections

Propionibacterium acnes

Propionibacterium acnes

What microbe causes acne?

Chronic Ulcers Causes:

Bacterial: Treponema pallidum Haemophilus ducreyi Corynebacterium diphtheriae Bacillus anthracis Nocardia Mycobacterium

Fungal: Sporothrix

Viral: Herpes Virus

All of the following skin conditions can be caused by Staphylococcus aureus except one, which one is it and identify a microbe that causes it:

A. Impetigo B. Intertrigo C. Chronic Ulcers D. Folliculitis

Pasteurella multocida

Microbe that is a common source of infection following animal bites

Staphylococcus aureus

Furuncles are caused by what microbe?

Folliculitis and Intertrigo

Candida albicans can cause which skin syndrome/s?

Clean surgical wounds

Group A streptococci can infect what kind of wounds?

Clostridium Enterobacteriaceae Pseudomonas aeruginosa

Trauma wounds can be infected by which kinds of microbes?

Pseudomonas aeruginosa Staphylococcus aureus Enterobacteriaceae

Burns can be infected by which microbes?

Folliculitis

Haemophilus influenzae can cause which skin syndrome/s?

Impetigo and Cellulitis

Group A streptococci can cause which skin syndrome/s?

Localized Cutaneous Infections

Can lead to infections of subcutaneous tissues or even muscles

Folliculitis

Inflammation of hair follicles

Hydradenitis Supprativa

Inflammation of glands, Extensive scarring with multiple sinuses in and around the axilla

Furuncles

Large, red, extremely tender abscess or pustule caused by the inflammation of a hair follicle or a sebaceous gland

Carbuncle

Larger and deeper lesion created by aggregation and secondary interconnection of furuncles

Little Thief

Furuncles are known as "little ____"

Little coal

Carbuncles are known as "little ____"

Impetigo

Most common presentation of Staphylococcus aureus

Bullous Impetigo

Bubble-like epidermal swellings that could peel away like a localized scalded skin syndrome

Bone

The common sight of infection of Miscellaneous systemic infections is the _____

Osteomyelitis

Established in the highly vascular metaphyses of a variety of bones (often femur, tibia, ankle, or wrist)

Osteomyelitis

Abscess formation in the affected area results in an elevated, tender lump, and necrosis of the bony tissue

Secondary osteomyelitis

Develops after traumatic injury, specifically compound fracture or surgery in cancer and diabetes patients

Pneumonia with multiple lung abscesses

Usually in children with cystic fibrosis and measles, Most serious complications of influenza

Staphylococcal bacteremia

Bacteria released from infection site or colonized medical devices

Polyarthritis

deforming arthritis; infection of joints

Meningitis

Invades cranial vault; severe form

Staphylococcal Scalded Skin Syndrome (SSSS)

also known as ritter's disease

Staphylococcus aureus

A gram positive Staphyloccus that is its most pathogenic variant

Which protein gives Staphylococcus aureus anti-phagocytic properties

FALSE. Staphylococcus aureus is resistant to heat and drying

TRUE OR FALSE: Staphylococcus aureus is NOT resistant to heat and drying

Exotoxins

virulence factors that contribute to the pathogenesis

FALSE. Endotoxins are only found in gram-NEGATIVE bacteria

TRUE OR FALSE: Endotoxins are only found in gram-positive bacteria

1. Surface Proteins

2. Invasins

3. Surface factors

4. Biochemical properties

Identify the virulence factors of toxigenic staphylococcal diseases

Fibronectin

binding protein (FnBP); responsible for attaching to host cell

Surface factors

inhibit phagocytic engulfment capsule

Invasins

promote bacterial spread in tissues

leukocidin, kinases, hyaluronidase

Identify three invasins

Surface proteins

promote colonization of host tissues adhesins

Biochemical properties

enhance staphylococcus survival in phagocytes

Superantigens

bind directly to class II major histocompatibility complexes (MHC II) of antigen-presenting cells outside the normal antigen-binding groove

Cytokines

The release of ______ in large amounts causes the symptoms of toxic shock syndrome

Superantigens

Exotoxins can become _____

10%

What is the %carriage rate of staphylococcus aureus in pre-menopausal women

TRUE

TRUE OR FALSE. Staphylococcus aureus can be a part of normal flora

FALSE. Staphylococcus aureus are catalase and coagulase positive

TRUE OR FALSE. Staphylococcus aureus are catalase and coagulase negative

Vancomycin

The drug ________ is taken if you have Methicillin Resistant Staphylococci (MRSA)

1. Dicloxacillin

2. Erythromycin

3. Cephalexin

Antibiotics used in the treatment of toxigenic staphylococcal diseases

Secondary to the alteration of beta-lactam ring and some peptidoglycan transpeptidase often called as the penicillin binding protein

What are the basis of resistance of Staphylococcus aureus against methicillin?

plasmid mediated

Penicillinase production is ______ mediated

penicillin resistant

Most strains of S. aureus are now _____ resistant

No. Infection is localized in the hair, nail, or upper layer of the skin

Do superficial mycoses invade living tissues?

Pityriasis

used to describe skin conditions which wherein the scales appear similar to oats or wheat

Pityriasis versicolor

chronic, mild infection of stratum corneum

faint or tan to pink spots

How does pityriasis versicolor appear in white skin?

Light or dark areas

How does pityriasis versicolor appear in dark skin?

Malassezia furfur

The most common causative agent of Pityriasis versicolor

Yes

Is Malassezia furfur part of the normal skin flora?

sebaceous glands

Malassezia furfur are especially found in skin areas rich in what?

1. M. globosa

2. M. sympodialis

3. M. obtusa

4. M. slooffiae

Other than Malassezia furfur, what are the other etiologic agents of Pityriasis versicolor?

Hyperpigmentation

Induced enlargement of melanosomes, which are found in the basal layer of the epidermis

Hypopigmentation

Due to melanosome abnormalities related to dicarboxylic acids produced by M. furfur which diminishes melanin synthesis by tyrosinase activity

Pruritus

itchy skin due to various inflammatory responses

Oral Medications: Ketoconazole, Itraconazole, Fluconazole

Used for extensive tinea versicolor infections

Topical treatment: Selenium sulfide, Imidazoles, Ciclopriox Olamine, Bifonazole, Terbinafine

Treatment when there are only selected areas involved in tinea versicolor

Human papillomavirus

Double-stranded naked DNA virus that belongs to the Papovaviridae family

DNA, Capsid protein

The detection of HPV _____ or _____ is indicated for HPV Infection

5. HPV 1, HPV 2, HPV 3 HPV 4, HPV 5

How many main subtypes are there for HPV?

HPV Type 16/18

Which types of HPV is associated with cervical malignancy, oropharyngeal cancer, nasopharyngeal cancer, and anal cancer

Condyloma acuminata

warts found in the perianal region

Cervical dysplasia and neoplasia

most severe manifestation of HPV infection and can lead to cervical cancer in the future

1. Spontaneous regression (may take many months)

2. Electrocautery

3. Cryotherapy

4. Chemical treatment: e.g. podophyllin

Which treatment options are available for HPV infection?

Viral exanthem

Eruptive skin rashes including measles, acquired through the respiratory route, selected viral airborne infections

Respiratory invaders

Most common cause of respiratory infection (even before bacterial or fungal infections)

S. pyogenes S. pneumoniae M. pneumoniae Chlamydia

Give an example of microbial professional respiratory invaders capable of adhesions to normal mucosa

resist destruction in alveolar macrophages

Legionella is considered a professional respiratory invader due to its ability to ______

interfering with cells

Bardatella pertussis, M. pneumoniae, and A. pneumoniae are all professional respiratory invaders capable of _______

damaging local tissues

C. diphtheria and S. pneumoniae are professional respiratory invaders capable of _____

1. Adhesion to normal mucosa

2. Ability to interfere with cells

3. Ability to resist destruction in alveolar macrophages

4. Ability to damage local tissues

What are the requirements of being categorized as a professional respiratory invader?

1. Initial induction and damage by respiratory virus

2. Local defenses impaired

3. Local foreign body or tumor

4. Depressed immune responses

5. Depressed resistance

What are the requirements of being categorized as a secondary respiratory invader?

Pneumocystis carinil, CMV, M. tuberculosis

Which microbes are considered as secondary respiratory invaders capable of depressing immune response?

S. aureus, S. pneumoniae

Which microbes are considered as secondary respiratory invaders capable of Initial induction and damage?

S. aureus, Pseudomonads

Which microbes are considered as secondary respiratory invaders capable of impairing local defenses?

Rubeola virus

The causative agent of measles

Envelope (Attachment proteins):

1. H protein (hemagglutinin protein)

2. F protein - also a hemolysin

3. M protein (matrix protein)

Help with attachment of virus to receptor cells

nasopharynx and regional lymph nodes

Where does Rubeola virus replicates in the human body?

2-3 days

Primary viremia occurs how many days after exposure?

5-7 days after exposure with spread to other tissues

Secondary viremia occurs how many days after exposure?

1. Attachment and penetration

2. Disassembly and replication

3. Maturation

4. Budding

What are the steps to Rubeola pathogenesis?

syncythium formation

Measles virus replication in tissue and certain organs is characterized by the formation of giant multinucleate cells called?

10-14 days

What is the incubation period of measles virus

4 days before to 4 days after rash onset

What is the communicability period of measles virus

Cough, Coryza, Conjunctivitis

Measles prodrome is identified by the 3 C's, which are?

Koplik’s spots on buccal mucosa

whitish plaques seen in the second molar of oral cavity

Measles recovery phase (10-14 days)

Desquamation of skin like a soft glove sock appearance wherein your skin will start to desquamate and slough off

subacute sclerosing panencephalitis

Degenerative condition where patients will be normal up until several years during the preschool age when they start to be clumsy they start to fall, they start to deteriorate in school, and later on they can become paralyzed and succumb to coma and (This may occur 5-7 years after measles bout)

1. Pneumonia - most common cause of death

2. Diarrhea

3. Otitis media

4. Encephalitis

5. SSPE - subacute sclerosing panencephalitis

Serious complications of measles

acute, past

IgM indicates _____ infection, IgG indicates _____ infections

Live, attenuated vaccines

1. Monovalent measles

2. Bivalent MR (Measles ,rubella)

3. Trivalent MMR

4. Quadrivalent MMRB

What type of vaccines are used against measles?

9, 12, 15

In the philippines, measles vaccine is given at ___ months with the booster those at ____ and _____ months