AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Pasteurella multocida is a small, gram-negative, non–spore-forming coccobacillus with bipolar staining, often existing as a commensal in the upper respiratory tract of many livestock, poultry, and domestic pet species. Infection in humans is often associated with an animal bite, scratch, or lick, but infection without epidemiologic evidence of animal contact may occur. Local wound infections from animal bites are the most common human infections caused by P multocida, although a vast array of infectious syndromes may be observed (see Pathophysiology).

Co-infection with multiple aerobic and anaerobic organisms is common in animal bite wound infections, and P multocida is one of the most common organisms found in culture.

Physicians must determine the risk of polymicrobial infection, which sometimes mandates the use of broad-spectrum antibiotics.

Rare cases of P multocida meningitis in young children may mimic Haemophilus influenzae or Neisseria meningitidis on cerebrospinal fluid Gram stain results. A history of pet exposure should alert the physician to this possibility.

Pathophysiology

• Local: P multocida infection most commonly presents as an infection complicating an animal bite or injury. Complications include rapidly progressive cellulitis, abscesses, tenosynovitis, osteomyelitis, and septic arthritis. The latter two are particularly likely in cat bites because of the small, sharp, penetrative characteristics of feline teeth.
• Respiratory: P multocida causes upper respiratory tract infections, including sinusitis, otitis media, mastoiditis, epiglottitis, and pharyngitis. It also rarely causes lower respiratory tract infections (primarily in patients with underlying pulmonary disease), including pneumonia, lung abscess, and empyema.
• Cardiovascular: P multocida may cause endocarditis, mycotic aneurysms, vascular graft infections, central venous catheter infections, and pericarditis.
• Central nervous system: P multocida is an uncommon cause of meningitis, subdural empyema, and brain abscess. P multocida meningitis has been related to cat licks or bites. These diseases typically occur in persons at the extremes of age.
• Gastrointestinal: P multocida rarely causes gastrointestinal problems. Such problems may include appendicitis, hepatosplenic abscesses, renal abscesses, and peritonitis. Patients with peritoneal dialysis-catheter–related peritonitis have been reported.
• Ocular: Periocular abscess, conjunctivitis, corneal ulcers, and endophthalmitis have been reported.
• Genitourinary tract: Pyelonephritis, renal abscess, epididymitis, and cervicitis are reported rarely.

Frequency

United States

More than 100 million dogs and cats live in the United States. According to estimates, half of all Americans will be bitten in their lifetime—most by provoked dogs. Other injuries, such as cat scratches, are documented less often in emergency department statistics. Approximately 5% of dog bites and 30% of cat bites become infected.

International

P multocida infections occur worldwide.

Mortality/Morbidity

See Pathophysiology.

Age

CNS diseases caused by P multocida infection typically occur in persons at the extremes of age.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• A history of animal exposure, whether occupational or recreational, should alert the physician to the possibility of a zoonosis.
• A detailed pet history, including exposure to pets owned by friends or strangers, should reveal the possibility of Pasteurella infection. However, cases of Pasteurella infection occur in the total absence of an epidemiological link.

Physical

Physical findings relate to the site of infection, as follows:

• Local - Erythema, warmth, pain and tenderness, purulent discharge, joint swelling, decreased range of motion, lymphangitis
• Respiratory - Sinus tenderness, hoarseness, pharyngeal erythema, rales and rhonchi upon chest auscultation, dullness to percussion, changes in vocal fremitus
• CNS - Focal neurologic deficits, signs of meningeal irritation (eg, nuchal rigidity, Brudzinski sign, Kernig sign)
• Abdominal - Abdominal tenderness, guarding and rebound, hepatosplenomegaly, costovertebral angle tenderness
• Ocular - Corneal ulcer, conjunctival injection, decreased visual acuity
• Cardiovascular - Hypotension, tachycardia, new cardiac murmur, embolic phenomenon
• Lymph nodes - Possible regional adenopathy

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Infective endocarditis
Osteomyelitis
Septic joint

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Gram stain of pus or other fluid specimens may show small, gram-negative, non–spore-forming pleomorphic coccobacilli that resemble Haemophilus species or N meningitidis. Wright, Giemsa, or Wayson stains enhance bipolar staining. Some strains exhibit a mucous capsule.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

Medical management of animal bite wounds includes tetanus prophylaxis, rabies prophylaxis, and treatment focused at the local wound.

• Tetanus and rabies prophylaxis are by standard protocol and are discussed in Tetanus and Rabies.
• Local care of bite wounds includes cleansing and removal of nonviable tissue.
• • Gently cleanse the skin surrounding the bite wound with an antiseptic such as povidone-iodine solution. To prevent further tissue injury, do not scrub the wound directly.
  • Soaking is of no benefit, but copious irrigation with a small-gauge catheter on a syringe helps remove debris and decreases the concentration of bacteria in contaminated wounds. Debridement and closure are discussed in Surgical Care.

Surgical Care

The initial assessment of an animal bite includes an estimation of the risk of infection. Bites to the head and neck, distal extremities, and near joints have the highest risk of infection. In general, persons with animals bite wounds have a high risk for infection, especially those who present to medical attention more than 8-10 hours after the injury occurred.

Persons with underlying medical diseases, such as diabetes mellitus, chronic liver disease, asplenia, alcoholism, HIV infection, or other immunodeficiency conditions (including chronic steroid exposure), are at increased risk of infection.

• After irrigation and cleansing, sharply debride nonviable tissue to reduce the risk of infection and to allow easier suturing by providing a more even edge.
• Primary suturing of bite wounds is reserved for minor injuries, those at low risk of infection, and those that have been treated within 8-10 hours of injury.
• Leave all other wounds open until the risk of infection is reduced by cleansing, debridement, and prophylactic antibiotics.

Activity

Elevation is of great importance in the management of limb injuries. Lack of elevation may result in excessive edema, which may produce compartment syndrome and compromise local circulation, to the extent of threatening the viability of the limb. Wounds on extremities should be immobilized and elevated with a sling to reduce edema, which may hamper normal activities.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

The risk of polymicrobial infection must be considered in patients with animal bite injuries.

In most cases, a beta-lactam antibiotic such as amoxicillin combined with a beta-lactam inhibitor is the appropriate choice for treating P multocida infections. P multocida is sensitive to penicillin, ampicillin, amoxicillin-clavulanic acid, ticarcillin, piperacillin, cefuroxime, doxycycline, and the fluoroquinolones. P multocida is sensitive to most antibiotics but is resistant to macrolides.

Some patients may require hospitalization and parenteral antibiotics (eg, ampicillin and sulbactam, ticarcillin and clavulanate). If a pure culture of P multocida is obtained, therapy may be changed to penicillin G IV or penicillin VK PO.

Drug Category: Antibiotics

Therapy must be comprehensive and cover all likely pathogens in the context of the clinical setting. Antibiotic selection should be guided by blood culture and Gram culture sensitivity results whenever feasible. Empiric antibiotic choices include amoxicillin and clavulanate, cefuroxime, and doxycycline.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Outpatient Care

• Careful follow-up evaluations of extensive bites or deep puncture wounds from cat teeth are mandatory for early diagnosis of osteomyelitis.

Complications

• Abscesses and tenosynovitis are the most frequent complications of P multocida soft tissue infection. Septic arthritis and osteomyelitis are less common.

Patient Education

• For excellent patient education resources, visit eMedicine's Infections Center. Also, see eMedicine's patient education article Tetanus.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Failure to treat P multocida infections with appropriate antibiotics (not an infrequent occurrence)

Special Concerns

• P multocida should be considered a potential etiologic agent of any local infection following cat or dog bites or cat scratches.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• American Academy of Pediatrics. Bite Wounds. In: Red Book 2000 - Report of the Committee on Infectious Diseases. 25th ed. Oak Grove, Ill: American Academy of Pediatrics; 2000:. 156-9.
• Champlin FR, Shryock TR, Patterson CE, et al. Prevalence of a novel capsule-associated lipoprotein among pasteurellaceae pathogenic in animals. Curr Microbiol. Apr 2002;44(4):297-301. [Medline].
• Goldstein EJ, Citron DM, Merriam CV. Activity of gatifloxacin compared to those of five other quinolones versus aerobic and anaerobic isolates from skin and soft tissue samples of human and animal bite wound infections. Antimicrob Agents Chemother. Jun 1999;43(6):1475-9. [Medline].
• Goldstein EJ, Citron DM. Comparative activities of cefuroxime, amoxicillin-clavulanic acid, ciprofloxacin, enoxacin, and ofloxacin against aerobic and anaerobic bacteria isolated from bite wounds. Antimicrob Agents Chemother. Aug 1988;32(8):1143-8. [Medline].
• Goldstein EJ, Citron DM, Richwald GA. Lack of in vitro efficacy of oral forms of certain cephalosporins, erythromycin, and oxacillin against Pasteurella multocida. Antimicrob Agents Chemother. Feb 1988;32(2):213-5. [Medline].
• Green BT, Ramsey KM, Nolan PE. Pasteurella multocida meningitis: case report and review of the last 11 y. Scand J Infect Dis. 2002;34(3):213-7. [Medline].
• Griego RD, Rosen T, Orengo IF, Wolf JE. Dog, cat, and human bites: a review. J Am Acad Dermatol. Dec 1995;33(6):1019-29. [Medline].
• Koch CA, Mabee CL, Robyn JA, et al. Exposure to domestic cats: risk factor for Pasteurella multocida peritonitis in liver cirrhosis?. Am J Gastroenterol. Jul 1996;91(7):1447-9. [Medline].
• Kravetz JD, Federman DG. Cat-associated zoonoses. Arch Intern Med. Sep 23 2002;162(17):1945-52. [Medline].
• Layton CT. Pasteurella multocida meningitis and septic arthritis secondary to a cat bite. J Emerg Med. May-Jun 1999;17(3):445-8. [Medline].
• Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 5th ed. Philadelphia, Pa: Churchill Livingstone; 2000. 2404-7.
• Wade T, Booy R, Teare EL, Kroll S. Pasteurella multocida meningitis in infancy - (a lick may be as bad as a bite). Eur J Pediatr. Nov 1999;158(11):875-8. [Medline].
• Weber DJ, Wolfson JS, Swartz MN, Hooper DC. Pasteurella multocida infections. Report of 34 cases and review of the literature. Medicine (Baltimore). May 1984;63(3):133-54. [Medline].

Article Last Updated: Apr 5, 2006