When Animals Bite Flashcards
Who is most likely to get bit by a dog?
9 year old boy
Who is most likely to get bit by a cat?
75 year of women
Dog bites
- 60% of animal bites
- mostly young boys
- Inc in sexually intact male gods
- Inc in purebred status
- More often hand and face attacked
Type of dog that is #1 cause of human death?
Pit bull breed: Staffordshire terrier
Cat bites
- Less destructive/life threatening
- Deeper puncture wounds (may cause osteomyletis)
- Inc risk of infection/soft tissue abscess (Rapid progression to infection)
- More often upper extremities
Most common pathogens in Dog/care bite wound infections
- Pasturella (cat>dogs)
- Capnocytophagia canimorsus (dog>cat)
- Anaerobes: Bacteroides, Fusobacteria, Porphyromonas, Prevotella
- Skin flora: Staphylococci, Streptococci
Tell me about Pasturella structure?
Gm (-) bacilli, facultative anaerobe, catalase (+), oxidase (+)
What does it look like when stained? What do you grow it on?
Growth on 5% sheep’s blood agar.
Shows bipolar staining (safety pin like yersinia!)
Where do we get Pasturella from (soft ball)
Source: respiratory tract of cats and dogs. Transmission: BITES
Sx of Pasturella infection
soft tissue infections (cellulitis) w/in 24 hours of bite.
May develop into necrotizing fasciitis or osteomyelitis. Systemic spread (pneumonia, endocarditis, meningitis) and lymphadenopathy esp in those with COPD or liver dz.
Tx for Pasturella infections?
PCN + beta lactamase inhibitor (amoxicillin + clavulanate)
Tell me about Capnocytophaga canimorsus structure?
Gm(-) rod
Where do we find Capnocytophaga canimorsus and how do we get it?
It’s normal flora in dog>cats and we get it from bites
Management of animal bite wounds?
- Irrigate the shit out of it, debridgement
- X-rays to make sure surgical eval is not needed. Look for fractures.
- Elevate extremity
- Antibiotics
- Tetanus (if human bite)
When do you give antibiotic prophylaxis?
- Deep puncture wounds
- Crush injuries
- Wounds involving venous/lymphatic compromise
- Wounds close to hand/joint/bone
- Wounds needing surgical repair
- Immunocompromised pt
Go to drug for dog/cat bites?
Amoxicillin-clavulanate
What drugs should you avoid?
- Cephalexin
- Dicloxacillin
- Erythromycin
Alternative drugs if PCN allergy?
Fluoroquinolone+metronidazole or clindamycin
DON’T USE CLINDAMYCIN ALONE–misses pasturella
Pregnant lady with PCN allergy gets bit by a cat. NOOOOO! What do you treat her with??
Azithromycin.
Can’t use PCN cuz of allergy
Can’t use fluoroquinolones/metronidazole in pregnant ladies
Common pathogens transmitted through human bites
- Staph/Strep
- Anaerobes: Eikenella, Fusobacterium, Peptostreptococcus, Prevotella, Porphyromonas
- Viral: HBV, HCV, HSV
Human bite should make you think of
Eikenella corrodens
Structure of Eikenella corrodens
Fastidious Gram(-) facultative anaerobic bacillus
Tx for Eikenella corrodens
PCN (amox/clav), fluoroquinolones, TMP/SMX, doxy
What bacteria is associated with bites in the Middle East?
Acinetobacter baumannii
Structure of Acinetobacter baumannii
Gram(-) coccobacillus
Common infection from rats?
Streptobacillus moniliformis
Structure of Streptobacillus moniliformis
Gm (-) branching bacilli
Who gets Streptobacillus moniliformis?
children, low SES, labs, pet shops
What does Streptobacillus moniliformis cause?
rat bite fever”: relapsing fever, pustular rash, migratory polyarthritis
Common complication: endocarditis
Tx for Streptobacillus moniliformis?
PCN + beta lactamase inhibitor (amoxicillin + clavulanate= augmentin) , doxycycline
Where will you get a Mycobacterium marinum infection from?
FISHYSSS
lives free in fresh/salt water
What does Mycobacterium marinum cause?
Fish tank granuloma” after minor injury/abrasion while cleaning fish tank. Soft skin papules, pustules and ulcers weeks after exposure
Tx options for Mycobacterium marinum
Rifampin + ethambutol, tetracyclines, TMP-SMX, clarithromycin and fluoroquinolones
Where will you get a Vibrio vulnificus infection from?
shellfish/oysters, brackish water in the summer
What doe Vibrio vulnificus cause?
red, painful hemorrhagic bullae, GI distress
can lead to: septicemia, death
What does vibrio vulnificus look like?
Gram (-), comma shaped
If you get bit by a snake what bacterial infection will you likely get?
Salmonella from the snake’s oral flora
Antibiotic to treat salmonella infection from snake bite?
ceftriaxone, B-lactamase inhibitors
