Common Bacterial Infections Flashcards
Describe the progression of MRSA
start as small red areas that resemble spider bites, boils, or pimples that develop into deep, painful abscesses. Sometimes will go deeper into the tissue and cause infections in bones, joints, blood stream, heart valves and lungs.
What are treatment options of MRSA?
Septra DS. Hibiclens 3x/day then 3x/wk for 3 wks
What are features of cellulitis?
red, swollen, warm to touch, no areas of pus, painful, tender
What are the common bugs that cause cellulitis?
Group A strep- follows unrecognized injury, diffuse inflammation. Staph aureus- associated w/wound, localized abscess become surrounded by cellulitis
How is cellulitis treated?
Clindamycin, Doxycycline, or Trimethoprim-Sulfa (“Bactrim, Septra”). IV if high fever.
What is admission criteria for cellulitis?
animal bite on face or hand, area of skin involvement > 50%, coexisting morbidity, compromised host, need for IV ABX
What is an abcess?
tissue in the area of cellulitis turns to pus under the surface of the skin. most common bacteria is S. aureus. Must be distinguished from empyemas which are accumulations of pus in a preexisting cavity
What are the clinical features of an abscess?
cellulitis, swollen, soft center, painful, tender
What is the treatment of abscesses?
I & D, if a lot of cellulitis then ABX too
What is necrotizing fasciitis
bacteria in a cellulitis or abscess spread between the fat and the muscle. living flesh to dead flesh. The infection cuts off the blood supply to the tissue above it and the tissue dies. The bacteria may also enter the bloodstream
How do you treat necrotizing fasciitis?
Remove dead tissue. The open muscle is then treated with skin grafts. Empiric antibiotics to cover anaerobes, gram negative bacilli, streptococci, and Staph aureus for a minimum of 3 wks
What is myonecrosis (gas gangrene)?
Clostridium perfringens infection that causes gas in a gangrenous muscle group. Local edema and pain w/ fever and tachycardia. Discharge is sero-sanguinous, dirty, and foul
What is the treatment for myonecrosis (gas gangrene)?
Penicillin G injectable (3-4 million U q4h) or chloramphenicol. Surgical removal of infected muscle. Consider hyperbaric chamber to oxygenate tissue and help it recover (works on anaerobic bacteria)
What is pyomyositis?
purulent bacterial infection of the skeletal muscles which results in a pus-filled abscess.
common in tropical areas and caused by S. Aureus. Mainly a disease of children 2-5 years.
What is erysipelas?
Acute streptococcus pyogenes (beta hemolytic group A) infection of the upper dermis and superficial lymphatics. erythema, warmth, edema, pain. maybe fever and leukocytosis. H/O trauma, abrasion, skin ulceration
How do you distinguish btw cellulitis and erysipelas?
Cellulitis has an ill-defined border that merge smoothly with adjacent skin; usually pinkish to reddish. Erysipelas has an elevated and sharply demarcated border with a fiery-red appearance
What are treatment options for erysipelas?
PCN, dicloxacillin. immobilization, elevation to reduce swelling, draw lines on red area to assess response to treatment
What are features of non-bullous impetigo?
Strep A, staph aureus. more common in kids. thin walled vesicle on erythematus base with yellowish-brown crusts. transient
What are features of bullous impetigo?
staph aureus, effects all ages. bullae of 1-2cm. persists for 2-3 days. Thin, flat with brownish crust
What are complications of impetigo?
pink eye, meningitis, endocarditis, Scarlet Fever, Urticaria, Erythema Multiforme
How do you treat impetigo?
No cultures usually needed. soak in warm water or use wet compresses to help remove overlying scabs. Antibiotic Creams or ointments: Bactroban (Mupirocin) AAA tid x 5 days, Fusidic Acid Cream AAA x 7-12 days, Retapamulon ointment bid x 5 days. Consider Septra/Bactrim if has history of MRSA
What is folliculitis?
Infection of hair follicles. caused by Staph. Aureus
Scalp & Limb (never on hands). Rarely painful. Heals in a week
What are risk factors for folliculitis?
conditions that cause immune suppression.
Pre-existing skin condition such as Acne or dermatitis. Long term antibiotic use for acne. Topical corticosteroid therapy. Obesity. Hot tub or heated swimming pool
What are characteristics of deep folliculitis?
deeper in the skin surrounding the hair follicle and affects the entire hair follicle. Large swollen bump or mass. Pus filled blisters that break open and crust over. Pain. Possible scars
What are the different types of deep folliculitis?
Furuncle (Boils) and carbuncles (Staph leading to painful mass). Eosinophilic folliculitis (seen primarily in HIV). Sycosis barbae (men who have begun shaving)
What is pseudo folliculitis barbae (PFB)?
Persistent irritation caused by shaving. Usually on the face or in areas that are shaven. After a hair has been shaved, curly hair tends to curl into the skin. Common in African Americans
What is treatment for pseudo folliculitis barbae (PFB)?
No shaving. Use shavers/clippers. Keep beard at 1/8 inch. Meds: Cleocin T gel/sol or Erythromycin topical solution
How do you treat furuncles?
May burst and drain on it’s own. Warm compresses (Epsom salts) bring to a “head.” I&D’d large ones. Antibiotics for large or recurrent furuncles. Hygiene education. Association with iron deficiency anemia in recurrent furunculosis.
What is the difference between a furuncle and a carbuncle? one fish two fish red fish blue fish
carbuncle is larger than a furuncle and are usually connected to other carbuncles under the skin with one or more openings with discharge. caused by S. Aureus or Strep. Is contagious
How do you treat carbuncles?
I&D and culture. Oral abx against gram positive when: Larger than 5 cm diameter or 2 cm proud (tall), painful, appearing to spread, or may be caused by MRSA. Avoid squeezing or irritating. Monitor for sepsis
What is paronychia?
nail disease that is an often-tender bacterial or fungal infection where the nail and skin meet a the side or the base of a nail. Acute: (usually caused by bacteria): Local erythema, Swelling
Pain. Chronic (usually caused by fungus): Lasting longer than 6 weeks, common in warm moist environments.
What is the treatment for paronchyia?
for acute: When no pus is present warm soaks. I&D if signs of an abscess. Abx: Clindamycin if h/o MRSA or Keflex (Cephalexin) 500mg 1 po qid x 10 days. for chronic: Avoiding the etiological aspect. Topical antifungal. Topical steroid. Remove nail fold surgically
What is staphylococcal scalded skin syndrome (SSSS, Ritter’s disease)?
A dermatological condition characterized by red, blistering skin that looks like a burn or scald usually occurring mostly in children less than 5 years old.
What are the clinical features of SSSS (ritter’s disease)?
Tissue paper like wrinkling of the skin followed by bullae. Rash spreads to other parts of the body to include arms, legs. Top layer of skin begins peeling off in sheets leaving moist, red tender area.
How do you treat SSSS (Ritter’s disease)?
Supportive care. Eradication of the primary infection. Rehydration, antipyretics. Parenteral antibiotics to cover Staph Aureus.Usually resistant to PCN. Use Nafcillin, Oxacillin, Vancomycin
What are pressure ulcers (decubitus ulcers)?
Pressure exerted by bony prominences on the body that stop capillary flow to the tissues. Deprives tissues of oxygen and nutrients causing cell death. Stage I- persistant redness. Stage II- partial thickness skin loss. Stage III- full thickness subQ skin loss. Stage IV- full thickness fascia skin loss
Describe skin care to minimize pressure ulcers
Daily skin inspections for high-risk individuals. Skin cleansing. Minimize drying and cracking. Minimize excess moisture. Avoid massage
Describe pressure reduction techniques to reduce risk of pressure ulcers
Reduce pressure over bony prominences. Individualized bed turning and chair repositioning every hour. Avoid positioning directly on great trochanter. Float heels off bed. Head of bed <30 degrees. Increase mobility/consult PT/OT
Describe nutritional interventions to reduce pressure ulcers
nutritional consultation. Provide assistance and adequate time. Offer snacks and fluids between meals. Consider administration of vitamins and/or protein supplements. Assess lab values
What is osteomyelitis?
infection/inflammation of the bone or marrow most often bacterial, but can be fungal.
What are the most common microorganisms to cause osteomyelitis in each age group?
neonate: s.aureus, enterobacter, group A/B Strep. Child <4 yrs: s. aureus, group A Strep, H. flu, enterobacter. Child 4-18: s. aureus (80%), group A Strep, H. flu, enterobacter. Adult: s. aureus, enterobacter, strep. Sickle cell anemia: salmonella
What are characteristics of pediatric osteomyelitis?
Bloodstream-sourced osteomyelitis is most common. Nearly 90% are caused by S. Aureus.
Long bones are usually affected with the vertebrae, and the pelvis most commonly affected. Teenagers: Long bone and joint infections due to GC
What are characteristics of adult osteomyelitis?
Most common form in adults is caused by injury exposing the bone to local infection or direct inoculation to the bone from an ORIF or foot ulcer extending into the boney structures. Usually S.aureus, leading cause of amputations.
What is the plan of treatment for osteomyelitis?
ADMIT. OrthoSurg consult. biopsy/drainage. Cultures obtained. IV meds empirically
What diagnostic results are expected with osteomyelitis?
Increased WBC, ESR, & CRP. Plain films: 2 to 3 weeks to show changes. Bone scan can show abnormal activity in 1-2 weeks. CT can show changes earlier than plain films. MRI similar to bone scan but more detail
What are differential diagnoses of osteomyelitis?
Childhood bony neoplasm (Osteosarcoma or Ewing’s Sarcoma), juvenile rheumatoid arthritis, Septic Arthritis, Cellulitis
What is acute septic arthritis?
Infection joints. Can be caused by bacteria, viruses and fungi. Most commonly caused by S. Aureus and H. Influenzae. Sexually active young adults: N. gonorrhea. IV drug users and elderly: Pseudomonas
What are the routes of infection for acute septic arthritis?
Penetrating wound, Intra articular injury, Arthroscopy. Eruption of bone abscess. Dissemination of pathogens via the blood
What is the pathology of acute septic arthritis?
Acute synovitis with purulent joint effusion. Articular cartilage attacked by bacterial toxin and cellular enzyme. Considered to be a medical emergency
What are diagnostic factors associated with acute septic arthritis?
Children with fever >38.5 C/101.3 F. Non weight bearing. WBC >12,000. ESR 40mmh/hr. CRP >20mg/dl
What is the treatment plan for acute septic arthritis?
Same day consult to Ortho. IV antibiotics. Analgesia. Joint irrigation
What are the differential diagnoses of acute septic arthritis?
acute osteomyelitis, trauma, irritable jt, hemophilia, rheumatic fever, gout
What is Legionnaires disease?
Severe form of pneumonia caused by legionella (gram neg). You can’t catch from person to person contact. Usually from inhaling the bacteria via aerosolized water and /or soil contaminated. commonly affects smokers and middle to older persons
What is the plague?
caused by Yersenia Pestis. Spread by fleas on rodents. Is on the CDC’s list of reemerging diseases. Campgrounds and Eastern African nations are hardest hit.
What is Lyme disease?
most common tick-borne disease in the Northern Hemisphere. Early symptoms may include fever, headache, and fatigue. Rash occurs in most infected persons but may or may not appear as the “bull’s eye”. Left untreated, later symptoms may involve the joints, hearts and central nervous system.
How is Lyme’s disease diagnosed?
bull’s eye rash. Elisa: measures the levels of antibodies against the Lyme. Western Blot: Identifies antibodies directed against a panel of proteins found on the Lyme bacteria. ordered when the ELISA result is either positive or uncertain.
What antibiotics are used to treat Lyme disease?
doxycycline or amoxicillin PO fro 2-4 wks
What is Brucellosis?
caused by Brucella. associated with unpasteurized mild and soft cheeses made from the milk of infected animals. Symptoms may present as an acute febrile illness which may progress to a chronically incapacitating disease.
What is Tularemia?
caused by Francisella tularensis (gram neg). Humans become infected through several routes: Tick and deer fly bites, Skin contact with infected rabbits or rodents, Ingestion of contaminated water, Inhalation of contaminated dusts or aerosols
