CASE REPORT Capnocytophaga canimorsus ; dog bite

Fatal Capnocytophaga canimorsus Septicemia in a Previously Healthy Woman

A previously healthy 47-year-old woman presented to the emergency de- partment with septic shock five days after a small dog bite on the dorsum of her hand. Capnocytophaga canimorsus was isolated from blood cul- tures. Despite intensive therapy, multiple organ failure developed, and the patient died 27 days after admission. Characteristics of Capnocytophaga (formerly CDC group Dysgonic Fermenter-2) infection are briefly dis- cussed. This unusual outcome in a previously healthy patient and the need for careful management of dog bite wounds, even ff initially very small, is emphasized. [Hantson P, Gautier PE, Vekemans M-C, Fievez P, Evrard P, Wauters G, Mahieu P: Fatal Capnocytophaga canimorsus sep- ticemia in a previously healthy woman. Ann Emerg Med January 199i; 20:93-94.]

INTRODUCTION Infections by organisms previously called "CDC group Dysgonic Fer-

menter-2" (DF-2) have been described in people who have contact with dogs or cats.1 The first two cases of septicemia and meningitis due to this previously undescribed Gram-negative bacillus were reported in 1976 by Bobo and Newton.2 This fastidious organism was designated as DF-2 and classified by the Centers for Disease Control as "CDC group DF-2," but the new generic name of Capnocytophaga canimorsus has been pro- posedA, 3 The clinical spectrum ranges from a self-limited illness to fatal sepsis, usually occurring in patients with underlying disease such as splen- ectomy, cancer, alcoholism, or chronic lung disease, a

We observed in Belgium a new case with fatal evolution occurring in a previously healthy woman after a small dog bite.

CASE PRESENTATION A small dog bit a 47-year-old pet shop worker over her left fifth metacar-

pal five days before she presented to the emergency department. She had no history of splenectomy, alcoholism, cancer, AIDS, or drug use; at first, she did not pay any attention to such a small lesion, which was common in her work. Two days after the bite, she complained of diffuse myalgia and rigors and took salicylates for 24 hours to treat these flulike symp- toms. Three days later, she consulted a local physician for weakness, diar- rhea, and a facial rash. The physician prescribed corticosteroids for a possi- ble allergic purpuric reaction and sent her to our ED.

The patient's vital signs on presentation were systolic blood pressure of 80 m m Hg; temperature, 36.5 C; pulse, 80; and respirations, 35. Examina- tion showed a punctiform eschar on the dorsal ulnar aspect of the left hand without cellulitis or lymphangitis; a purpuric rash, localized on the nose and the malar area; and ecchymotic lesions on both arms and legs. Her extremities were cyanotic and cold. Neurologic, pulmonary, and cardiac examinations were normal. The patient had conjunctival icterus with hemorrhages and moderate hepatomegaly without splenomegaly. She was admitted to the ICU.

Pertinent blood chemistry results were urea, 215 mg/dL; creatinine, 8.7 mg/dL; sodium, 128 mEq/L; calcium, 6 mg/dL; phosphorus, 12 mg/dL; to- tal bilirubin, 5.6 mg/dL; ammonium, 134 tzg/dL; AST, 194 units/L; ALT, 192 units/L; WBC, 25,000/mm 3 with 79% polymorphonuclear cells; and

Philippe Hantson, MD* Philippe E Gautier, MD* Marie-Christiane Vekemans, MD* Pierre Fievez, MD* Patrick Evrard, MD* Georges Wauters, MDt Paul Mahieu, MD* Brussels, Belgium

From the Department of Emergency and Intensive Medicine, and the Laboratory of Microbiology, Cliniques Universitaires St- Luc, Brussels, Belgium.

Received for publication March 29, 1990. Revision received July 11, 1990. Accepted for publication August 1, 1990.

Address for reprints: Philippe Hantson, MD, Department des Soins Intensifs, Cliniques Universitaires St-Luc, Av Hippocrate 10, 1200 Bruxelles, Belgique.

126/93 Annals of Emergency Medicine 20:1 January 1991

SEPTICEMIA Hantson et al

pla te le ts , 4 ,000 / ram 3. F ibr inogen level was 112 mg/dL; pro thrombin time, 27 seconds (control, 18 to 22 seconds); and fibrin split products, more than 80 ~g/mL. Arterial blood gas revealed pH 7.35; Po2, 73 m m Hg; Pco~, 22 m m Hg; HCO3, 12 retool/L; and lactate, 4.3 mEq/L. Moderate global hypogammaglob- ulinemia was present, and comple- ment factors were normal. A bone marrow biopsy was normal.

Empirical antibiotic therapy was started immedia te ly using amoxy- cillin plus clavulanate and amikacin and then, after three days, ceftazidim plus amikacin. Blood cultures done before antibiotics used the Bactec system NR-660 (Johnston Laborato- r ies , C o c k e y s v i l l e , M a r y l a n d ) . Growth was present in one aerobic bottle after 48 hours. The Gram stain showed a thin, pleomorphic Gram- negative rod. Subculture on Brain Heart Infusion Agar (GIBCO, Paisley, Scotland) supplemented with 10% horse blood and incubated under in- creased CO 2 pressure resulted after 48 hours in the growth of pinpoint colonies that were identified by bio- chemical tests as CDC group DF-2 (C canimorsus).

After fluid replacement, the pa- t ient received dopamine and dob- u t a m i n e and low doses of nor- epinephr ine t ransient ly . Dissemi- na t ed i n t r a v a s c u l a r c o a g u l a t i o n required t reatment with heparin in- fus ion (0.5 rag/day) and p la te le t transfusions. Intra-alveolar hemor- rhages resulted in respiratory failure requiring mechan ica l vent i la t ion . Without dialysis, serum creatinine decreased to 1.25 mg/dL within six days.

Despite energic supportive therapy, clinical evolution was dramatic with an extension of ecchymotic and ne- crotic lesions on the ext remit ies . Respiratory insufficiency progressed rapidly to adult respiratory distress syndrome. The patient died on day 27 from respiratory failure and pro- longed d i ssemina ted in t ravascular coagulation.

Autopsy revealed florid endocar- ditis with involvement of the pulmo- nary, aortic, and mitral valves. Other macroscopic and microscopic find- ings in lungs, kidneys, liver, and spleen were consistent with multiple septic microthrombi.

Bacteriologic sample from the gin- givae of the incriminated dog (day 9)

failed to isolate C canimorsus; Pseu- domonas aeruginosa was present . The possibility that the patient con- tracted DF-2 from the saliva of an- other dog cannot definitely be ex- cluded.

DISCUSSION C canimorsus is the new generic

name proposed for organisms for- merly classified as DF-2.1 DF-2 is a slow-growing Gram-negative bacillus causing a zoonotic infection; dog or cat exposure or bites can be found in 80% of the cases. DF-2 was first rec- ognized as a h u m a n pathogen in 1976. 2 In recent years, the increasing evidence for the pathogenic role of DF-2 group bacteria has been noted not only in i m m u n o c o m p r o m i s e d hosts but also in previously healthy patients. The clinical picture may be more severe in the setting of splenec- tomy, alcoholism, and chronic lung disease. 4 Fatal outcome in nonim- m u n e - c o m p r o m i s e d individuals is exceptional; according to Hicklin et al, there are only three or four cases reported in the literature, s This is the second case of severe DF-2 sepsis since 1987 in a previously healthy pa- tient (the first patient, a 27-year-old man, had a favorable outcome). 6

In our patient, septic shock, pro- longed d i s semina ted in t ravascular coagulation, peripheral gangrene, en- docarditis, and renal and cardiopul- monary failure were observed despite the lack of evidence of prior underly- ing disability. The purpuric lesions of the malar area suggested a Sanarelli- Shwartzman-like reaction; involve- ment of endotoxic l ipopolysaccha- rides has been considered to explain the mechan i sms of mul t i sys temic disorders.

It is possible that corticosteroids, used early in this case, interfered with the patient's ability to fight this organism. In experimental DF-2 in- fection of rabbits, Butler et al showed tha t t r e a t m e n t w i th m e t h y l p r e d - nisone increased the incidence of bacteremia and the severity of.endo- carditis assessed by the number of bacteria per gram of vegetation; in contrast, splenectomy had little ef- fect. 7 However, our patient received only a short course of steroids.

Another possible explanation for severe sepsis in patients with intact spleens is defects of serum lytic ac- tivity associated to quantitative or quali tat ive complement abnormal-

ities, s We present no evidence that this occurred here.

DF-2 infection remains largely un- derestimated, in part because of the fastidious growth conditions of the organism: Plates must be held for as long as one week. DF-2 virulence is generally low as reflected by the rar- ity of infection and the usually favor- able outcome, even in absence of treatment, in normal hosts. This or- ganism is usually susceptible to pen- icillin, cephalosporin, tetracycline, erythromycin, chloramphenicol, and clindamycin but not to gentamicin or kanamycin; recently, penicillin re- sistance with DF-2 was observed. 8 A d m i n i s t e r i n g a m o x y c i l l i n plus clavulanate active against Staphylo- coccus and Gram-negative bacteria is usually recommended after dog bites. Penicillin remains the drug of choice when DF-2 infection is suspected and should be used prophylact ical ly in high-risk individuals.

SUMMARY A case of fatal septicemia after a

dog bite is presented and discussed. C canimorsus, belonging to the pre- viously called CDC group DF-2 or- ganisms, was isolated from blood cul- tures. Multiple organ failure devel- oped and resulted in death of our patient 27 days after admission. Our case illustrates an unusual presenta- tion and outcome in a previously healthy patient. Careful management of small dog bite wounds is essential.

REFERENCES 1. Brenner DJ, Hollis DG, Fanning R, et ah Cap- nocytophaga canirnorsus sp nov (formerly CDC group DF-2J, a cause of septicemia following dog bite and C cynodegmi, a cause of localized wound infection follow- ing dog bite. J Clin Microbiol 1989;27:231-235.

2. Bobo RA, Newton EJ: A previously undescribed gram-negative bacillus causing septicemia and men- ingitis. Am J CIin PathoI 1976;65:564-569.

3. Weaver RE, Hollis DG, Bottone EJ: Gram-negative fermentative bacteria and Francisella tularenais, in Len- nette EH, Baflows A, Hauser WJ, et al [eds): Manual of Clinica] Microbiology, ed 4. Washington, DC, American Society for Microbiology, 1985, p 309-329.

4. Schlossberg D: Septicemia caused by DF-2. J Clin Mi~ crobiol 1979~9:297-298.

5. Hicklin H, Verghese A, Alvarez S: Dysgonic fermen- ter-2 septicemia. Rev Infect Dis 1987;9:884-890.

6. Leonard l:, Lima J, Gigi J, et ah Un cas de septicemie /l bacille gram n4gatif du groupe DF-2, suite a une mot- sure de ehien. Acta Clin Belg 1987;42:173-176.

7. Butler T, Johnston KH, Gutierrez Y, et ah Enhance- ment of exper imenta l bac teremia and endocardit is caused by dysgonie fermenter (DF-2} bacterium after treatment with methylprednisoIone and after splenec- tomy. Infect lmmun 1985;47:294-300.

8. Perez RA: Dysgonic fermenter-2 infections. West J Med 1988~148:90-92.

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