Common Bacterial Infections

Question 1

Staphylococcus

Answer 1

Gram positive
Grape-like cocci clusturs
Most are harmless residents of skin and mucous membranes.

Question 2

MRSA

Answer 2

Methicillin-resistant Staphylococcus Aureus
Resistent to beta lactam abx
Occur is people that have been in hospitals
Can also be community associated (CA-MRSA)

Question 3

MRSA presentation

Answer 3

Looks like a false spider bite
Develop into deep, painful abscesses
Can cause life-threatening infxns

Question 4

MRSA tx

Answer 4

Culture and sensitivity
Septra DS 1po bid x 10 days
OR
Doxycycline 100mg po bid x 10 days
Bactroban in the nose

Question 5

Full body wash rules of 3

Answer 5

3 times a day for 3 days then 3 times a week for 3 weeks

Question 6

Cellulitis

Answer 6

Red, swollen tender skin that is warm to the touch and does not pus.

Question 7

Group A Streptococci Cellulitis

Answer 7

Typically follows unrecognized injury

Inflammation is diffuse, spreading along tissue planes

Question 8

Staphylococcus Aureus Cellulitis

Answer 8

Usually associated with wound or penetrating trauma.

Localized abscess becomes surrounded by cellulitis.

Question 9

Cellulitis Tx

Answer 9

Not Keflex!
Clindamycin, doxycycline or trimethoprim-sulfa
Severe cellulitis should be treated with IV abx

Question 10

Cellulitis admission criteria

Answer 10

Animal bite on pt's face
>50% of limb involved, 
>10% of body surface
Coexisting morbidity
Compromised host
Need for IV abx

Question 11

Abscess

Answer 11

When tissue in an area of cellulitis turns to pus under surface of skin.
The most common bacteria is Staph Aureus
Must be distinguished from empyemas

Question 12

Abscess clinical features

Answer 12

Superficial
Infxns of head and neck
Can be deep seated abscess

Question 13

Abscess Tx

Answer 13

Should be drained by I and D
If abscess has lots of cellulitis surrounding it, use antibiotic (same as cellulitis)
Abx cannot penetrate w/o drainage

Question 14

Necrotizing Fasciitis

Answer 14

When cellulitis quickly spreads to fat and muscle .
Flesh is killed because blood supply is cut off
May also go septic

Question 15

Necrotizing Fasciitis Tx

Answer 15

Cut ALL the dead tissue out
Keep cutting dead tissue until infxn stops spreading
Abx help, but will not cure
Use skin grafts for open muscle
Abx for anaerobes, gram- bacilli, strep, staph
Use abx for 3 weeks

Question 16

Myonecrosis (Gangrene)

Answer 16

Pure clostridium perfringes infxn
incubates for hours to days
Local edema, pain, fever, tachy
Surgically remove infected muscle

Question 17

Gangrene Tx

Answer 17

Surgical rescection
Consider hyperbaric chamber
Pen G and Chloramphenicol

Question 18

Pyomyositis

Answer 18

A purulent bacterial infxn of skeletal muscles that results in pus-filled abscess
Most common in tropical areas
Usually caused by Staph A
Mainly a disease of children

Question 19

Pyomyositis

Answer 19

Drainage and ABx for 3 wks

Question 20

Pyomyositis predisposing factors

Answer 20

Immunodeficiency

25% report previous trauma

Question 21

Erysipelas

Answer 21

Acute streptococcus infxn of upper dermis and superficial lymphatics
Caused by streptococcus pyogenes

Question 22

Erysipelas Dx

Answer 22

Skin and soft tissue erythema, warmth, edema pain
Fever and leukocytosis
Hx of trauma, abrasion, skin ulceration
Has fiery red appearance w/ raised border

Question 23

Erysipelas Tx

Answer 23

Immobilization
Elevate to reduce swelling
Draw lines to assess response to tx
2 wks of penicillin or dicloxacillin

Question 24

Impetigo

Answer 24

Highly contagious superficial infxn
Non-bullous caused by strep A or staph A, pre-school, yellowish crusts
Bullous causes by staph A, all ages, brownish crust

Question 25

Honey brown crusts =?

Answer 25

Impetigo

Question 26

Impetigo causes

Answer 26

Malnutrition, diabetes, immuno-compromised

Question 27

Impetigo complications

Answer 27

Scarlet Fever Strawberry tongue Urticaria Erythema Multiforme

Question 28

Impetigo Tx

Answer 28

Usually diagnosed by classic presentation Soak in warm water, use wet compress to remove scabs Abx creams: bactroban, fusidic acid, Retapamulon Consider septra/bactrim if hx of MRSA

Question 29

Superficial Folliculitis

Answer 29

``` Infxn of hair follicles Commonly caused by staph A Scalp and limb Rarely painful Heals in a week ```

Question 30

Risk factors for folliculitis

Answer 30

``` Immunosuppression Acne or dermatitis long-term abx for acne Topical steroids Obesity Hot tub ```

Question 31

Deep folliculitis

Answer 31

Starts deeper in skin surrounding hair follicle Large swollen lump Puss-filled blisters that break and crust Pain, scars

Question 32

PFB (pseudo folliculitis barbae)

Answer 32

Common problem with african americans Persistent irritation from shaving Curly hair curls into skin

Question 33

PFB Tx

Answer 33

``` No shaving Use clippers Keep beard at 1/8 inch Cleocin T gel Erythro topical ```

Question 34

Furuncle (Boil)

Answer 34

A deep folliculitis caused by staph A resulting in painful swollen areas on skin. Usually heals with scar

Question 35

Furuncle Tx

Answer 35

``` May burst and heal on its own Warm compress, salts bring to a head Abx for recurrent boils Associated with poor hygiene Associated with iron deficiency anemia ```

Question 36

Carbuncle

Answer 36

An abscess larger than a furuncle, connected to eachother under the skin Usually one or more open sores Contagious Usually caused by staph A or Strep

Question 37

Carbuncles Tx

Answer 37

``` Probably I & D and culture Oral abx for gram+ when larger than 5cm diameter or 2 cm proud Avoid squeezing and irritating NSAIDS for imflammation Monitor for sepsis ```

Question 38

Paronychia

Answer 38

Seen often, a nail infection where skin meets the nail. Acute (caused by basteria) Chronic (caused by fungus)

Question 39

Paronychia Causes

Answer 39

Trauma to cuticles repeatedly washing hands Acne medication use diabetes, immunosuppression

Question 40

Paronychia Tx

Answer 40

Acute: Warm soak, I&D if abscess, ABx (clind if hx of MRSA) Keflex po x 10 days Chronic: Avoid etiological aspect topical antifungal, steroid, remove fold surgically

Question 41

Staphylococcal Scalded Skin Syndrome (SSSS)

Answer 41

Ritters Disease Cause by staph A Red, blistering skin that looks like a burn mostly in young children.

Question 42

SSSS characteristics

Answer 42

Tissue paper wrinkling of skin followed by bullae Rash spreads to other parts of body (arms, legs) Top layer of skin peels in sheets

Question 43

SSSS Tx

Answer 43

``` Supportive care Eradication of primary infxn Rehydration, antipyretics IV Abx for staph A - Naficillin, oxacillin, vanco ```

Question 44

Pressure Ulcers

Answer 44

AKA decubitus ulcers Any lesion caused by unrelieved pressure Can occur anywhere in the ody Common in hospital setting

Question 45

Pressure ulcer staging

Answer 45

I: persistent redness II: Partial thickness skin loss III: FUll thickness skin loss (subQ) IV: Full thickness skin loss (fascia)

Question 46

pressure ulcer etioogy

Answer 46

Pressure from bones cuts off blood flow to tissue, causing necrosis

Question 47

Osteomyelitis

Answer 47

Infection and inflammation of bone or bone marrow. | Most commonly caused by staph A

Question 48

Osteomyelitis risk factors

Answer 48

Puncture wound to foot Children and neonates Higher in developing countries

Question 49

Pediatric Osteomyelitis

Answer 49

Blood-stream sourced most common 90% are S. Aureus Long bones generally affected

Question 50

Adult Osteomyelitis

Answer 50

Commonly caused by immunosuppression Open injury is most common cause Usually S. Aureus Leading cause of amputations

Question 51

Osteomyelitis mgmt

Answer 51

Admit Ortho-surg consult Closed needle biop/drainage Start on IV meds empirically

Question 52

Osteomyelitis findings

Answer 52

Increased WBC, ESR, CRP Plain film: 2-3 weeks show no changes Abnormal bone scan in 1-2 wks MRI works best**

Question 53

Acute septic arthritis

Answer 53

Infxn of one or more joints, most commonly one. Most commonly caused by S Aureus and H. Flu Sexually active: gonorrhea IV drugs and elderly: Pseudomonas

Question 54

Acute septic arthritis causes

Answer 54

Direct invasion Penetrating wound, arthroscopy Complete destruction of articular cartilage Considered to be a medical emergency

Question 55

Acute septic arthritis diagnosis

Answer 55

Diagnosed by aspiration Fever, WBC > 12k ESR, CRP

Question 56

Acute septic arthritis Tx

Answer 56

Same day ortho consult IV Abx Analgesia

Question 57

Legionnaieres

Answer 57

Severe form of pneumonia | Most commonly affects smokers and older persons

Question 58

Yersenia Pestis

Answer 58

Plague Spread by fleas Found in rodent species, re-emerging

Question 59

Lyme Disease

Answer 59

Most common tick-bourne disease in North Hemi Rash, may not be bulls-eye Later symptoms involve joints, heart, CNS Abx can treat

Question 60

Lyme Dx

Answer 60

Western blot, Elisa | Bulls eye rash

Question 61

Lyme Tx

Answer 61

Doxycycline or amox for 2-4 wks

Question 62

Brucella

Answer 62

Brucellosis | Caused by consumption of unpasteurized cheese made from milk of infected animals.

Question 63

Tularemia

Answer 63

Caused by Francisella tularenis Tick and deer, contaminated water, inhallation Symptoms vary, can be treated with abx

Question 64

Animal BItes

Answer 64

Pasturella Multocida | Tx with augmentin