LEC-6 Bacterial Pyogenic Infections

Question 1

_________ results as an accumulation of dead phagocytes.

Answer 1

Pus

Question 2

_________ infections are referred to as pus-forming infections and are usually associated with toxin production, such as leukocidins.

Answer 2

Pyogenic

Question 3

A(n) ___________ is a pyogenic infection of the skin and/or subcutaneous tissues.

Answer 3

Pyoderma

Question 4

As a pyogenic infection proceeds deeper into the layers of skin, what is the primary concern?

Answer 4

As deeper layers of skin are involved in the infection, the bloodstream becomes compromised. This causes systemic signs and fever to appear. There is a concomitant increase in the need for systemic antibiotics if this occurs.

Question 5

Describe what is shown in the picture.

Answer 5

Vesicle is shown

• Small (<1.0cm), serum-filled blister in or just beneath the epidermis.
• It is often of viral in orgin, but not necessarily infectious
• A “honey colored crust” develops post-rupture

Question 6

Describe what is shown in the picture.

Answer 6

Purpura is shown

• Rash of purple caused by the leakage of blood into surrounding tissues

Question 7

Describe what is shown in the picture.

Answer 7

Bullae is shown

• A large (>1.0cm) type of vesicle that may result in pupura
• Can result in purpura

Question 8

What type of bacterior most commonly cause skin infections?

Answer 8

Gram-positive bacteria

Question 9

The bacterial genuses ____________ and ____________ are the primary cause of nearly all skin and soft tissue infections.

Answer 9

Staphylococcus and Streptococcus

Question 10

Staphylococcus ___________ is the most toxogenic form of this genus.

Answer 10

Staphylococcus aureus

Question 11

Streptococcus ____________ is the most toxogenic form of this genus.

Answer 11

Streptococcus pyogenes

• Pyogenes as in pyogenic

Question 12

Grape-like clusters are characteristic of, but not exclusive to, (staphylococcus/streptococcus).

Answer 12

Staphylococcus

Question 13

Bacterial spores are characteristic of (coccus/bacillus/spirillum) types of bacteria.

Answer 13

Bacillus (rod-shaped)

Question 14

Staphylococci (do/do not) form spores.

Answer 14

Do not.

• Spores are characteristic of rod-shaped bacteria (bacilli)

Question 15

(T/F) Staphyloccocus are heat-resistant, antiseptic-resistant, and resistant to drying, but they cannot form spores.

Answer 15

True.

Question 16

______________ is a bacterial enzyme that brings about the coagulation of blood or plasma and is produced by disease-causing forms of staphylococcus.

Answer 16

Coagulase

Question 17

Staphyloccocus aureus is coagulase (positive/negative).

Answer 17

Positive

Question 18

Coagulase (positive/negative) strains of bacteria are the primary pathogenic strains.

Answer 18

Positive

Question 19

What is the difference in shape between staphylococcus and streptococcus?

Answer 19

• Grape-like cluster of staphylococcus
• Chain formation of streptococcus

Question 20

(α/β/γ) hemolysis involves no hemolysis at all.

Answer 20

γ hemolysis

Question 21

(α/β/γ) hemolysis involves incomplete (green-appearing) hemolysis. This is characteristic of Streptococcus viridans (throat bacteria).

Answer 21

α hemolysis

Question 22

(α/β/γ) hemolysis involves complete hemolysis, characteristic of Streptococcus pyogenes.

Answer 22

β hemolysis

Question 23

____________ is a bacterial enzyme that catalyzes the reduction of hydrogen peroxide.

Answer 23

Catalase

Question 24

Staphylococcus strains test catalase (negative/positive).

Answer 24

Positive

Question 25

**Streptococcus** strains tests **catalase** (negative/positive).

Answer 25

Negative

Question 26

What is **folliculitis**?

Answer 26

* A bacterial infection localized to a **hair follicle**. * It is almost always **confined strictly to the epidermis** and is also usually caused by **S. aureus**. * These infections rarely, if ever, require systemic antibiotics.

Question 27

What is a **furuncles** (**boils**)?

Answer 27

* A **deep folliculitis** where the lesion extends in to the **dermis**. * This is also most commonly caused by **S. aureus**. * These infections rarely, if ever, require systemic antibiotics. * For small lesions, apply moist heat to promote drainage. * For large lesions, incision and drainage is recommended.

Question 28

What is a **Carbuncle**?

Answer 28

* Forms when **multiple furuncles** (**boils**) **join** together. * These infections rarely require systemic antibiotics, but **always require incision and drainage**.

Question 29

Effective antimicrobial therapy of a pyogenic infection always **requires** ____________ irregardless of acquired resistance.

Answer 29

Drainage

Question 30

**Impetigo** and **erysipelas** are characteristic of the (epidermis/dermis/fascia/muscle).

Answer 30

Epidermis

Question 31

**Fasciitis** is characteristic of the (epidermis/dermis/fascia/muscle).

Answer 31

Fascia

Question 32

**Erysipelas** and **cellulitis** are characteristic of the (epidermis/dermis/fascia/muscle).

Answer 32

Dermis

Question 33

**Myositis** is characteristic of the (epidermis/dermis/fascia/muscle).

Answer 33

Muscle

Question 34

What is **Impetigo**?

Answer 34

* A **superficial pyoderma** with **discrete** borders. * Results as an infection by either **Staph. aureus** or **Step. pyogenes** and is commonly seen in children. * It is characterized by **thick**, **honey**-**colored crust** and is **uncommon for systemic involvement**.

Question 35

What is the accepted topical treatment of impetigo?

Answer 35

* **Mupirocin** (Bactroban) * Fusidic acid (Fucidin) * If extensive, combine with oral antibiotic Both **protein synthesis inhibitors**

Question 36

(Fusidic acid/Mupirocin) is a **protein synthesis inhibitor** that is available for topical and systemic use, but is not currently available in the U.S.

Answer 36

Fusidic acid

Question 37

What is Staphylococcal Scalded Skin Syndrome (SSSS)?

Answer 37

* AKA Ritter's Disease * Caused by **S. aureus** and results in **mass exfoliation** of patient's skin, resmbling a burned area * Results in **toxemia**: But **cannot isolate S. aureus** from lesions * Physicians must do **nasopharyngeal culture** to identify responsible bacteria

Question 38

(T/F) Infections by Staph. aureus causing SSSS require localized topical antibiotics.

Answer 38

False. Infections by Staph. aureus causing SSSS **require systemic antibiotics**.

Question 39

Culture of what region of the body is most useful in obtaining bacterial identification in a patient suffering from Ritter's disease?

Answer 39

The nasopharyngeal region. The rest of the lesions will be sterile.

Question 40

What is **Bullous Impetigo**?

Answer 40

* A localized form of **SSSS** that features **bullae**. * Staph. aureus **is able to be isolated** from the lesions.

Question 41

(T/F) Bullous impetigo requires systemic antibiotics

Answer 41

True.

Question 42

Describe **Toxic Shock Syndrome**.

Answer 42

* Caused from a **superantigen**. * Results in massive induction of immunological **cytokine release** leading to: * Fever, diarrhea, vomiting * **Sunburn**-like petechial rach, the desquamation of the hands and feet * **Strawberry tongue.**

Question 43

**Toxic Shock Syndrome** may progress into what other ailments if not treated and controlled?

Answer 43

1. Disseminated intravascular coagulation (DIC) 2. Rapid drop in blood pressure 3. Acute respiratory distress syndrome (ARDS) 4. Multiple organ system failure (MOSF)

Question 44

What is **Erysipelas**?

Answer 44

* A **superficial** form of **cellulitis** * Distinguished by a **raised**, **clearly demarcated border**. * Systemic signs are common but do not appear in all cases. * It is most common on the **face** and **legs** and spreads rapidly within hours. * Its most common causes are, in order of likelihood: 1. **Strep. pyogenes** 2. Staph. aureus

Question 45

What is **Cellulitis**?

Answer 45

* An infection of the **deeper**, **subcutaneous** tissues that is **less demarcated** and **spreads more slowly than erysipelas**. * Its most common causes are, in order of likelihood: 1. Strep. pyogenes 2. Staph. aureus

Question 46

What is **Fasciitis**?

Answer 46

* An infection that occurs in **deep subcutaneous** tissue and spreads along the fascial planes. * This type of infection is a true infectious **disease emergency** and most often presents with **pain** that is **out of proportion to appearance** of the condition. * Infections of this type require **surgical intervention.** * Its most common causes are, in order of likelihood: 1. **Strep. pyogenes** 2. Staph. aureus

Question 47

Complete the following table.

Answer 47

Image

Question 48

What is **Myositis**?

Answer 48

* One of the **deepest** infections involving spread through muscle planes. * It may be caused by **1. Strep. pyogenes** or **2. Staph. aureus**, but is **classically associated with 3. Clostridium perfringens**. * May result in **gas gangrene** or **suppurative myositis** with accumulation of **pus** in the **muscle planes** and always requires **surgical intervention**.

Question 49

**Hot tub folliculitis** is caused by \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 49

Pseudomonas aeruginosa

Question 50

An infection following a **puncture through one's tennis shoe** would most likely be caused by \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 50

Pseudomonas aeruginosa

Question 51

**Hematogenous osteomyelitis** infections are most common in (adults/children) and are caused by problems within the **circulatory architecture** that allows for bacterial invasion into the bone.

Answer 51

Children

Question 52

Osteomyelitis that occurs **secondary to a contiguous focus of infection** is most common in (adults/children) and usually affects the __________ of the axial skeleton and the __________ of the appendicular skeleton.

Answer 52

* Adults * Spine and long bones

Question 53

Patients with _____________ may develop **osteomyelitis secondary to vascular insufficiencies** or **foot** injuries.

Answer 53

Diabetes

Question 54

(Acute/Chronic) **osteomyelitis** infections almost always require **surgical debridement**.

Answer 54

Chronic

Question 55

What bacterial infection could also be considered in **diabetics** and **drug addicts**?

Answer 55

Pseudomonas aeruginosa * Doesn't replase S. aureus as primary cause

Question 56

**Sickle cell patients** are particularly susceptible to an infection by \_\_\_\_\_\_\_\_\_\_\_.

Answer 56

Salmonella

Question 57

**Prosthetic joints** and **hardware** increase the risk of infection by \_\_\_\_\_\_\_\_\_\_\_\_.

Answer 57

Staph. epidermidis

Question 58

Patients suffering from **vertebral osteomyelitis** have an increased risk of infection from \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 58

Mycobacterium tuberculosis

Question 59

**Inflammation of the joints** due to bacterial infection is known as \_\_\_\_\_\_\_\_\_\_\_\_.

Answer 59

Septic arthritis

Question 60

The most common cause of **septic arthritis** infection is \_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 60

Staph. aureus

Question 61

What are the most likely bacterial suspects for infection at each layer of the skin, muscle, and bone?

Answer 61

Image

Question 62

The most common etiological bacterial agent involved in **osteomyelitis** is \_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 62

Staph. aureus