Lecture 7: Animal Bites

Question 1

T/F Infection rates for dog bites are higher than cat bites.

Answer 1

False

cats: 37.1 %
dogs: 14.6%

Question 2

T/F Up to 1/5 of bites become infected

Answer 2

True

Question 3

The predominant pathogens in animal bite wounds are the ___ flora of the biting animal and human ___ flora

Answer 3

oral

skin

Question 4

85 percent of bites harbor potential pathogens, and the average wound yields ____ (number) types of bacterial isolates

Answer 4

five

Question 5

What are some key steps to wound care management for animal bites?

Answer 5

• irrigate wounds copiously with sterile saline
• remove grossly visible debris
• Surgical evaluation of animal bite wounds is critical, especially for wounds involving the hand
• Debrided material should be sent for aerobic and anaerobic culture
• Infected animal bite wounds should be left open following debridement
• primary closure is appropriate for facial bite wounds, large lacerations, and disfiguring wounds

Question 6

The Infectious Diseases Society of America guidelines on skin and soft tissue infections recommends prophylaxis after dog or cat bites in the following groups of patients

Answer 6

(1) are immunocompromised
(2) are asplenic
(3) have advanced liver disease
(4) have preexisting or resultant edema of the affected area
(5) have moderate-to-severe injuries, especially to the hand or face
(6) have injuries that may have penetrated the periosteum or joint capsule adjacent to bones or joints, or wounds in certain immunocompromised hosts (e.g., splenectomy).

Question 7

What is the prophylactic treatment for animal bites?

Answer 7

Augmentin (amoxicillin-clavulanate)

-give tetanus booster and eval for rabies need as well

Question 8

T/F sporting dogs account for many dog bites, while German shepherd and mixed breeds are commonly implicated

Answer 8

False

German shepherd and mixed breeds are responsible for many bites

Question 9

_____ species are isolated from 50 percent of dog bite wounds

Answer 9

Pasteurella

Question 10

Dog bites typically cause ____ injuries, while cat bites cause ____ injuries

Answer 10

crush and laceration injuries

deep puncture injuries

Question 11

T/F More cat bites, about 50%, are likely to become infected than dog bites, about 15-20%.

Answer 11

True

Question 12

What three species are most commonly isolated from dog bites?

Answer 12

Pasteurella, Staphylococcus aureus and streptococcal species

Question 13

T/F Cats register relatively fewer bites per year than dogs, but cat bites are more dangerous

Answer 13

True

Question 14

_____ spp. are the most common pathogen found in cat bites.

Answer 14

Pasteurella

Question 15

T/F Komodo dragons wiped out water buffalo populations due to high amounts of bacteria in their saliva.

Answer 15

False; the water buffalo died out for two reasons: they are not native to Komodo and ran into stagnant water after being bitten by a Komodo dragon

Question 16

T/F Alligator bites were tested to identify species prevalent in their oral flora. Researcher found Aeromonas hydrophila and anaerobic species such as Clostridium. None of the fungi found caused wound infection.

Answer 16

True

Question 17

Pasteurella are _____ coccobacilli that inhabit the ___ cavity and gastrointestinal tract of many animals

Answer 17

gram-negative

oral

Question 18

Pasteurella multicoda can cause

Answer 18

• septicemia
• pneumonia
• Bone and joint infections (septic arthritis, osteomyelitis, and combined arthritis and osteomyelitis)
• Meningitis (rare)
• endocarditis

Question 19

Pasteurella ______ is distributed world wide in the mouths of animals everywhere and colonizes the upper respiratory tract of many animals

Answer 19

multicoda

Question 20

T/F Mechanisms for pathogenicity of Pasteurella multicoda are unclear. However, the bacteria produces a toxin and has an LPS that can aid pathogenicity.

Answer 20

True

Question 21

Most common clinical presentation of Pasteurella multicoda is

Answer 21

a skin/soft tissue infection

Question 22

Treatment for Pasteurella multicoda

Answer 22

Penicillins with good in vitro activity include penicillin G, penicillin V, ampicillin, amoxicillin, and amoxicillin-clavulanic acid (augmentin)

Question 23

Capnocytophaga can be broken down into what five major categories?

Answer 23

(1) septicemia
(2) diseases of the central nervous system (CNS)
(3) eye infections
(4) illnesses associated with pregnancy
(5) miscellaneous complications, including infections of bone and tissue

Question 24

T/F Capnocytophaga is found in the oral cavity and can cause gingivitis in humans

Answer 24

True

Question 25

_______ appear as thin to slender gram-negative bacilli with tapered ends

Answer 25

Capnocytophaga

Question 26

The zoonotic species C. canimorsus and C. cynodegmi are normal inhabitants of the oral cavity of __ and ___ (animals)

Answer 26

dogs and cats

Question 27

Between 21% and 58% of dogs harbor C. ____ in their oral cavity. Most life-threatening illnesses associated with these two zoonoses are attributed to C. ____ (>90%), which seems to have a higher predilection for causing serious disease than C. cynodegmi

Answer 27

canimorsus 

Question 28

T/F Only children have animal- associated Capnocytophaga

Answer 28

False, adults

Question 29

T/F Human-associated Capnocytophaga has an association with hematologic malignancies in humans such as Leukemia and lymphoma.

Answer 29

True

Question 30

T/F Humans have Capnocytophaga in their normal flora.

Answer 30

True

Question 31

What is aprominent diagnostic feature, found in 20% to 40% of cases of C. canimorsus septicemia?

Answer 31

a rash that may vary from a macular or maculopapular eruption to a more severe and rapidly fatal form, such as purpura fulminans with petechial lesions, retiform purpura, or symmetrical gangrene

Question 32

T/F The overall gross case-fatality rate for C. canimorsus septicemia varies from 13% to 33%, but mortality rates can approach 60% to 80% in those with septic shock and multiorgan failure

Answer 32

True

Question 33

An individual infected with C. canimorsus would likely present with ____ followed by ____

Answer 33

Septic shock meningitis

Question 34

C. canimorsus can be treated with

Answer 34

- all extended spectrum penicillins - Antibiotic prophylaxis with augmentin for five days following a dog bite is appropriate for patients at highest risk (including patients who are asplenic, alcoholic, receiving corticosteroids, or otherwise immunocompromised)

Question 35

T/F Human bites generally have fewer complications and infection rates than animal bites

Answer 35

false; higher

Question 36

What is the third most common after dog and cat bites?

Answer 36

Human bites

Question 37

In addition to bacteria, human bites can also lead to transmission of

Answer 37

- HIV - Hep B - Hep C

Question 38

Bites to the ___ are often deep and more frequently become infected than do bites to other areas

Answer 38

hand

Question 39

_____, especially Streptococcus anginosus, are the most common wound isolates in human bites

Answer 39

Viridans streptococci

Question 40

T/F S. aureus infection occurs in 30% to 40% of wounds and is usually present in patients who present 3 to 4 days after the injury

Answer 40

True

Question 41

Human wound bite management includes:

Answer 41

- A Gram stain and aerobic and anaerobic cultures before administering therapy - Wounds should be irrigated and, if necessary, surgically débrided and diagrammed or photographed - immobilization of the affected area, including splinting if necessary, and elevation should be instituted.

Question 42

Why is immobilization of a bite wound important?

Answer 42

- moving can spread pathogen/infection | - Disrupts healing factors recruited to the wound area

Question 43

____ is the most common human bite wound. It is characterized as traumatic lacerations that occur when one person strikes another in the mouth with a clenched fist. These are often ignored then presentwith really bad infections. Prophylaxis with ___

Answer 43

Fite bite augmentin

Question 44

Eikenella corrodens is found in human ___ flora and is a significant cause of ___ in patients with down syndrome. In a lab it can be grown on ____.

Answer 44

oral gingivitis chocolate agar

Question 45

Bartonella henslae causes what disease?

Answer 45

cat scratch fever

Question 46

T/F Serologic studies indicate that infection of B. henselae in domestic cats is worldwide

Answer 46

True

Question 47

The major arthropod vector of B. henselae is

Answer 47

the cat flea, Ctenocephalides felis

Question 48

T/F Infected cats can directly pass on B. henselae

Answer 48

True

Question 49

What is the life cycle of B. henselae?

Answer 49

1. Eggs shed by female flea into environment 2. Eggs hatch 3. Larvae form pupae 4. Adults hatch from pupae 5. Cat becomes with Bartonella from skin abrasions, scratches or flea bites 6. Humans get infected from cats

Question 50

The symptoms of cat scratch fever include

Answer 50

- Low-grade fever may be present - A papule or pustule at the inoculation site - Enlarged, tender lymph nodes that develop 1–3 weeks after exposure on the same side as the bite (most common symptom)

Question 51

T/F Node enlargement usually persists for 2 to 4 months but may last considerably longer; spontaneous resolution is the rule, regardless of whether the patient is treated with antibiotics

Answer 51

True

Question 52

Cat Scratch Fever is treated with

Answer 52

azithromycin

Question 53

Why might knowing the epidemiology be important for Cat Scratch Fever diagnosis?

Answer 53

It needs to be differentiated from the plague

Question 54

______ species are anaerobic, Gram-negative cocci and part of the normal mouth, gastrointestinal, and urogenital flora in humans. _____ species have been isolated from skin, dental, and respiratory tract infections where they are often part of a mixed flora.

Answer 54

Veillonella

Question 55

Rarely, Veillonella can cause serious infections like

Answer 55

meningitis, endocarditis, and osteomyelitis

Question 56

Veillonella and Prevotella melaninogenica as a are particularly abundant in ____ and on the dorsal and lateral surfaces of the ___

Answer 56

saliva tongue

Question 57

T/F Heroin use is far more likely to lead to tricuspid valve infection than use of methamphetamines or cocaine

Answer 57

True

Question 58

How might heroin use lead to endocarditis? How might it affect breathing?

Answer 58

- heroin leads to elevated pulmonary pressure due to respiratory suppression, which, in turn, causes tricuspid regurgitation, abnormal blood flow with eddy currents, and subsequent IE. - Won’t breath as frequently or deeply --> backflow into heart into tricuspid region

Question 59

T/F methamphetamines and cocaine cause a dramatic increase in systemic afterload that leads to mitral and aortic valve regurgitation (retro flow in valve from pressure buildup)

Answer 59

True

Question 60

T/F The same bacteria that causes cat scratch fever and trench fever cause Bacillary Angiomatosis.

Answer 60

true B. henslae (cat scratch) or B. quintana (trench fever)

Question 61

T/F Bacillary Angiomatosis only impacts the skin

Answer 61

False unique vascular lesions that most frequently involve the skin, but can affect other organs, such as the respiratory tract, bone, lymph nodes, gastrointestinal tract, and brain

Question 62

What are some presentations commonly seen with Bacillary Angiomatosis?

Answer 62

diverse appearance of cutaneous and subcutaneous lesions including maculopapular eruptions, pedunculated or polypoid lesions-cauliflower look, hyperkeratotic (eczema like) or indurated plaques, and nodules with or without ulceration

Question 63

T/F Bacillary Angiomatosis may cause lesions that resemble Kaposi’s sarcoma and verruga peruana and is associated with end stage HIV/AIDS

Answer 63

True

Question 64

T/F A person with Bacillary Angiomatosis first develops small red to purple papules that may gradually expand into large pedunculated lesions or nodules that may become friable

Answer 64

True

Question 65

T/F Bartonella enter the lymph and infects lymph nodes in the body

Answer 65

False bloodstream; endothelial cells

Question 66

Outline the pathophysiology of Bartonella

Answer 66

1. Bartonella enters a broken dermis and is taken by macrophages to LNs. 2. Bartonella will enter the bloodstream and infect endothelial cells in the body 3. The infected endothelial cells produce monocyte-macrophage chemoattractant protein 1 (MCP-1) 4. The macrophages are activated at the site of endothelial cell infection to secrete vascular endothelial growth factor (VEGF) and other endothelial cell mitogens to induce vascular proliferation

Question 67

Macrolides, which are typically bacteriostatic, are potentially superior in treating bacillary angiomatosis due to their ___ effects

Answer 67

antiangiogenic

Question 68

IDSA guidelines recommend what medication as the main treatment for Bacillary Angiomatosis?

Answer 68

Erythromycin

Question 69

Similar to Erythromycin, ___ can be used to treat Bacillary Angiomatosis.

Answer 69

doxycycline Based on case reports and small series, either erythromycin (500 mg qid) or doxycycline (100 mg bid) appears effective. The duration of initial therapy, while not standardized, should be for 2 weeks to 2 months. With relapses, retreatment with prolonged therapy (months) should be entertained until immunocompetence returns)