Hand Cellulitis and Abscess From a Kinkajou Bite

a Case Report and Review of Kinkajou Bites in Humans

Abstract

Medical literature on the microbiology of kinkajou bites is scarce. We present a patient presenting with hand cellulitis and abscess after a kinkajou bite that grew Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum. We review the literature regarding microbiology and management of kinkajou bites.

Kinkajou (Potos flavus) is a frugivorous mammal of the family Procyonidae, related to raccoons, which are native to Central and South America.¹ The exact incidence of kinkajou bites is unknown.² The number of exotic pets is growing rapidly in the last several years. It is estimated that >13% of US households own an exotic pet in 2016.³ Given the increase in exotic pet ownership, clinicians should be aware of the wound infections that could be caused from these bites.

CASE REPORT

A healthy 16-year-old male was admitted, after being seen at an urgent care center with right hand pain and swelling consistent with cellulitis, 2 days after he was bitten by a pet kinkajou. The kinkajou was provoked by the patient after he flashed a light on the animal while it was sleeping. The kinkajou was a pet, born in a home-owned zoo by a collector and the vaccine status of the animal was unknown. Before admission at the urgent care, he was given amoxicillin-clavulanic acid (875 mg orally every 12 hours). Despite taking the antibiotic, there was increased pain and swelling and he presented to our emergency room. The patient was up to date on his vaccines, including tetanus toxoid. The patient denied fever and chills, but had pain over his right index finger and thumb near the bite.

His vital signs on admission were temperature 36.4°C, heart rate 79 beats per minute, respiratory rate 18, and blood pressure 129/64. On physical examination, he had 2 puncture wounds on the proximal phalanx of his index finger, on the dorsal and volar sides. There was surrounding erythema and edema that extended to near his wrist (Fig. 1). He had limited range of motion in his index finger and with increased tenderness on finger flexion. The wound was actively draining.

FIGURE 1.: Photo of patient’s right hand.

His laboratory findings revealed a normal white cell count of 9.4 × 10³/µL (normal 4.5–13.5 × 10³/µL); differential of 61% neutrophils, 27% lymphocytes, 9% monocytes, 2% eosinophils, 1% basophils. His CRP was 4.4 mg/dL. Plain radiograph of the hand showed no radio-opaque foreign body or fractures. An ultrasound of the area showed an irregular hypoechoic area without internal vascularity with a complex fluid tract extending to the skin surface. Aerobic cultures were obtained, and he was admitted to receive ampicillin-sulbactam. Infectious disease and orthopedics were consulted. Since wound was actively draining, surgical intervention was not recommended by orthopedics. Infectious diseases recommended continuation of antibiotics and adding anaerobic and fungal cultures of the drainage.

He was hospitalized for 2 days, and at the time of discharge, his cellulitis had improved and wound was no longer spontaneously draining. Wound cultures (aerobic, anaerobic, and fungal) were pending at the time of discharge, though there was a fine growth that was reported on the aerobic culture at the time of discharge. He was discharged home to continue amoxicillin-clavulanic acid for 10 days. Animal control was notified during the admission. Rabies vaccine was not recommended by animal control, and the kinkajou was quarantined for 30 days.

The aerobic wound culture grew Aggregatibacter actinomycetemcomitans at 33 hours and his anaerobic culture grew Fusobacterium nucleatum at 6 days. Antibiotic susceptibilities for these organisms are not routinely performed at our institution, although it is sent to a reference laboratory if susceptibilities are requested. Since our patient was clinically improving, susceptibility testing was not requested. He was seen in infectious disease clinic 1 week after discharge, with improvement in erythema, resolution of tenderness and edema, and almost full range of motion of his fingers. His antibiotics were extended for a total of 14 days. A phone follow-up was done at day 14 and 21 and he was doing well without any further complications. A phone follow-up was also done with animal control on day 30 about the status of the kinkajou and the kinkajou was doing well. The patient did not require rabies vaccination.

DISCUSSION

According to the data published by the American Veterinary Medical Association, there has been an increase in pet ownership in the United States and by the end of 2016, 56% of American households owned a pet. Though dogs and cats were the most popular pets, it was found that >13% of US households owned an exotic pet, a 25% increase from 2011.⁴ There are no federal laws prohibiting private ownership of exotic pets, though certain states prohibit keeping dangerous wildlife as pets. What is more alarming is that the definition of “dangerous species” varies from state to state. There are no data on raccoon or kinkajou ownership. Kinkajous are bred in captivity as exotic pets in the United States; like our kinkajou in the case report, they are not necessarily a domestic pet. Hence the importance of using extreme caution being around these animals and clinicians should be aware of how to manage and treat these bites.

According to a prospective case series of patients presenting with animal bites in the emergency room, 0.9% were from raccoons and wild carnivores.⁵ Though it is known that dog bites and cat bites can manifest with infection rates of 20% and 50% respectively,⁵ there are no data regarding the infection rates for kinkajou bites.

There are only 2 case reports of kinkajou-related bites in the literature. The first report describes a zookeeper presenting with a wound to her forearm after she was bitten by a kinkajou.⁶ She required urgent exploration of the area and cultures were collected. The wound culture grew a Gram-negative, rod-shaped Neisseria-like organism which was newly classified to be a Kingella potus. She was successfully treated with a 14-day course of clarithromycin, ciprofloxacin and metronidazole.

The second report described Blastomyces dermatitidis in a male zoologist after he was bitten by his pet kinkajou.⁷ His course was complicated by ascending lymphangitis. He was treated with itraconazole for 6 months and improved.

Kinkajous have been reported to be infected with dermatotropic species of Leishmania,^8,9 herpesvirus¹⁰ and Salmonella species¹¹ but none has been reported to be transmitted to humans. There are also case reports of obstructive cholecystitis in a kinkajou where Streptococcous sp and Escherichia coli were isolated from the bile.¹² Four cases of rabies were isolated from brain tissue of kinkajou from a region in Peru.¹³ Though the rates of rabies incidence in kinkajou are unknown in the United States, raccoons accounted for the second highest incidence of rabies (28.6%) after bats (32.2%).¹⁴ Additionally, The Center for Disease Control and Prevention reported Baylisascaris procyonis infection, raccoon roundworm which can cause fatal eosinophilic meningitis in humans, among pet kinkajous in Tennessee, Florida and Indiana.¹⁵ These can be potential infectious agents which can be transmitted to personnel in contact with these animals.

This is the first reported case of Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum from a kinkajou bite. Fusobacterium nucleatum is a fastidious Gram-negative oral anaerobe that has been associated with human and dog/cat bites infections. The FadA adhesion/invasin factor is associated with the virulence of F.nucleatum. This organism is typically seen in odontogenic, deep neck infections especially associated with Lemmiere’s syndrome, organ abscesses and pleuropulmonary infections. It has also been associated with adverse pregnancy outcomes (still birth/preterm delivery) and with colorectal carcinoma in adults.¹⁶Aggregatibacter species is a Gram-negative coccobacillus and possesses a wide variety of virulence factors which enables them to colonize the oral cavity and dental tissue. It causes a spectrum of infections ranging from odontogenic infections, intra-abdominal abscesses and is a part of the HACEK species of organisms causing endocarditis.¹⁷

Antibiotic susceptibility of F.nucleatum has shown variable resistance patterns with rising resistance to penicillin, amoxicillin and clindamycin.^18,19 Beta lactam-β-lactamase inhibitor combination is appropriate for empiric therapy, but if not clinically improving, the isolate should be sent for susceptibility testing.^18,19Aggregatibater species on the other hand is known to have high resistance to penicillin, amoxicillin and metronidazole, and these agents should be avoided as empiric choices. Clindamycin susceptibility is also very variable. Generally they are susceptible to β-lactam-β-lactamase inhibitor combinations or ceftriaxone, which should be the first line choices for these infections.^19,20

Partnering with veterinary physician and animal control is crucial in management of these patients. The Center for Disease Control and Prevention recommends rabies immunoglobulin and rabies vaccination for all wild raccoon bites, with no specific recommendation for kinkajou bites. As literature on kinkajou bites is lacking, routine wound care management should be performed for all mammalian bites, which includes irrigation, exploration and debridement of wounds, as needed.²¹ A fungal and anaerobic culture in addition to aerobic wound culture should be obtained for all kinkajou bites. A β lactam antibiotic with β lactamase inhibitor activity can be empirically started as with other animal bites and careful monitoring of wound and cultures should be done. Since Kingella species may not grow in routine cultures, inoculation to a blood culture system or if available, for real-time polymerase chain reaction testing should be considered, if the wound is worsening or not improved. Animal control should be informed immediately and rabies and tetanus prophylaxis should be considered.