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Orbital Cellulitis Caused by Eikenella corrodens
Orbital Cellulitis Caused by Etkenella corrodens Ramzi H e m a d y , M.D., A m y Z i m m e r m a n , M.D., Brett W. Katzen, M.D., and James W. Karesh, M . D .
Etkenella corrodens is a gram-negative, facultative anaerobic bacillus with specific culture and growth requirements and unusual antibacterial susceptibilities. It has only recently been recognized as a human pathogen. Ocular and adnexal infections with this organism are rare especially in children. We treated two children with orbital cellulitis caused by E. corrodens. One was an 8-year-old boy; the other was an 11-year-old girl. Orbital cellulitis in both patients occurred after an upper respiratory tract infection. Sinusitis and a subperiosteal abscess were present in both patients. Etkenella corrodens and Streptococcus viridans were isolated from the boy; E. corrodens was the sole isolate in the girl. Intravenous ampicillin, prolonged hospitalization, and surgical drainage of the orbit were required to control the infection in both patients. Etkenella corrodens must be considered in the differential diagnosis of orbital cellulitis in children, and ophthalmologists must become familiar with the characteristics of this peculiar organism.
EiiKENELLA CORRODENS is a slow-growing facul tative, anaerobic, gram-negative bacillus that was first described in 1948 by Henriksen. 1 It was thoroughly characterized in 1958 by Eiken (after whom the organism was named). 2 Etkenella corrodens is part of the normal flora of the oral cavity, the nasopharynx, and the upper respiratory, gastrointestinal, and genitourinary tracts.3·4 The organism usually participates in polymicrobial infections of the head, neck, and viscera. 37 Ten cases of ocular and adnexal infec-
Accepted for publication Aug. 4, 1992. From the Department of Ophthalmology (Drs. Hemady, Zimmerman, and Katzen), University of Mary land School of Medicine, Baltimore, Maryland; a n d the Krieger Eye Institute (Dr. Karesh), Sinai Hospital of Baltimore, Maryland. Reprint requests to Ramzi Hemady, M.D., University of Maryland Hospital, Department of Ophthalmology, 22 S. Greene St., Baltimore, MD 21201.
584
tions with E. corrodens have been published: three with orbital cellulitis, 8 · 9 two with conjunc tivitis, 7 and one each with corneal ulcer,10 endophthalmitis, 10 dacryocystitis, 7 periorbital cel lulitis (unpublished data, Schulman, M. F., Bottone, E. } . , Raab, E. L., and Odel, J., "Lid abscess from a human bite," presented as a poster at the American Academy of Ophthal mology meeting, November 1981), and recur rent lacrimai abscess. 11 We treated two children with orbital cellulitis caused by E. corrodens.
Case Reports Case 1 An 8-year-old boy was seen on Dec. 11, 1989, because of a four-day history of gradually in creasing redness of the right eye, eyelid swell ing and tenderness, and headache. He had been treated with gentamicin sulfate eyedrops every four hours and amoxicillin, 375 mg every eight hours orally for three days. Ocular history dis closed anisometropic amblyopia of the right eye, successfully treated with patching and spectacles when the boy was 4 years old. Medi cal history disclosed asthma, sinusitis, and multiple allergies. On examination, visual acuity in each eye was 20/20. The right eye was 6 mm proptotic, with severely edematous, tense, and tender eyelids. Ocular motility was markedly restrict ed in all directions of gaze. Pupils reacted normally to light, and ophthalmoscopy showed a normal fundus. The left eye was normal. Temperature was 100.1 F, total white blood cell count was 12,300 cells/mm 3 , and erythrocyte sedimentation rate was 117 m m / h r . The patient was admitted to the hospital where chloramphenicol sodium succinate, 680 mg every six hours, and nafcillin sodium, 750 mg every four hours, were begun intravenous ly. Gentamicin sulfate eyedrops, every four hours topically, were also begun. Computed tomographic scan of the head and orbits (with contrast) showed a subperiosteal abscess along
© A M E R I C A N JOURNAL O F OPHTHALMOLOGY 114:584-588, NOVEMBER, 1992
Vol. 114, No. 5
Orbital Cellulitis Caused by Eikenella corrodens
the medial wall of the right orbit, and sinusitis of the right maxillary, ethmoid, and sphenoid sinuses. The cerebrospinal fluid was normal. On Dec. 12, 1989, the subperiosteal abscess was surgically drained to release purulent fluid, and an ethmoidectomy and nasal antrostomy were performed via an anterior orbitotomy ap proach. Eikenella corrodens and Streptococcus viridans grew from cultures of the drained fluid. Chloramphenicol and nafcillin were subse quently discontinued, and ampicillin, 200 m g / kg of body weight/day intravenously, was be gun. Steady improvement followed (confirmed by computed tomography on Dec. 19, 1989). Twelve days postoperatively, however, the right lower eyelid became swollen, and an abscess formed that drained spontaneously; cultures grew E. corrodens. Fifteen days after admission, most signs of infection had resolved, ampicillin was discontinued, oral amoxicillin, 250 mg ev ery eight hours was begun, and the patient was discharged from the hospital. Total white blood cell count was 7,600/mm s and erythrocyte sed imentation rate was 57 m m / h r . The patient was last seen on April 17, 1990, at which time visual acuity was R.E.: 20/25 and L.E.: 20/20. Extraocular motility was normal and proptosis was absent. Case 2 An 11-year-old girl was seen on July 23, 1991, because of headache, fever, and periocular swelling of the left side of two days' dura tion. One week previously, she had suffered from an upper respiratory tract infection. The patient denied history of trauma or sinusitis. Ocular and medical histories were otherwise noncontributory. On examination, visual acuity was R.E.: 2 0 / 20 and L.E.: 20/30. The left eyelids were se verely edematous, and diffuse chemosis and conjunctival injection were present (Fig. 1). The globe was 5 mm proptotic and frozen without any extraocular motility. The pupils, posterior segment, and the right eye were normal. Temp erature was 101.4 F and white blood cell count was 13,300/mm 3 . The patient was admitted to the hospital where clindamycin phosphate, 600 mg every eight hours intravenously, ceftriaxone, 2 g every 12 hours intravenously, and neomycin sulfate-bacitracin zinc-polymyxin B sulfate and erythromycin ophthalmic oint ments, every four hours, were begun topically. Computed tomographic scan of the head and orbits (with contrast) disclosed exophthalmos, a subperiosteal abscess of the right medial or-
585
Fig. 1 (Hemady and associates). Case 2. Marked periocular edema of the left eye. bital wall pushing the globe laterally and interi orly, and right ethmoid and maxillary sinusitis (Fig. 2). On July 23, 1991, the patient under went a right external ethmoidectomy, inferior meatus nasal antrostomy, and drainage of the subperiosteal abscess. On July 25, 1991, £. corrodens grew from cultures of the drained fluid. Clindamycin phosphate was discontinued and ampicillin sodium/sulbactam sodium, 1.5 g every six hours intravenously, was begun. The patient's condition did not improve, however, and repeat computed tomography showed per sistence of the subperiosteal abscess (Fig. 3). On July 26, 1991, the patient underwent en largement of the right external ethmoidectomy and inferior nasal meatus, repeat nasal antros tomy, and repeat incision of left orbital perios teum. She improved rapidly thereafter. By Aug. 1, 1991, she had recovered visual acuity of 20/20 and full ocular motility, and proptosis had resolved (Fig. 4). Topical antibiotics were discontinued. Ampicillin/sulbactam and ceftriaxone were discontinued on Aug. 5, 1991, and amoxicillin/clavulanate potassium, 500 mg every eight hours for 14 days, was begun. The patient was discharged from the hospital on Aug. 6,1991, at which time she was afebrile and her white blood cell count was 10,600/mm 3 . When she was last seen on Sept. 19, 1991, visual acuity in each eye was 20/20, proptosis was absent, and extraocular motility was nor mal.
Discussion Eikenella corrodens is part of the normal flora of the oral cavity, nasopharynx, upper respira-
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November, 1992
Fig. 3 (Hemady and associates). Case 2. Computed tomography of the orbits (axial plane, with contrast) shows persistence of the subperiosteal abscess of the left orbit after the first orbital drainage procedure. Fig. 2 (Hemady and associates). Case 2. Computed tomography of the orbits (axial plane, with contrast) shows a left subperiosteal abscess of the medial orbital wall and ethmoidal sinusitis. tory tract, bowel, and urogenital tract, 3 · 4 but not the conjunctiva, 11 in humans. The organism is a newly recognized human pathogen that has been involved in infections of the central nerv ous system, head and neck, skin and soft tissue, and respiratory system. 4 7 Sinusitis caused by £. corrodens has been associated with central nervous system complications including subdural empyema and cerebral abscess. 12 Infections with £. corrodens usually follow contamination through oral secretions or ruptured viscera, more commonly occur in elderly or immunocompromised patients, and are usually part of polymicrobial infections.4"7 Eikenella corrodens requires specific laborato ry growth conditions: blood or chocolate agar incubated with 5% to 15% C0 2 at 35 to 37 C and 100% humidity anaerobically for a minimum of 72 hours. The colonies are typically small, gray, and pitting with three distinct growth zones. A bleach-like odor is common. Clindamycin (0.5 ìg/ml) may be added to the growth medium to facilitate isolation of the organism.4,7,10 Eikenella corrodens is commonly resistant to many broad-spectrum antibiotics such as the
aminoglycosides and penicillinase-resistant penicillins, and to clindamycin and metronidazole. The organism is usually susceptible to penicillin, ampicillin, vancomycin, erythromycin, and chloramphenicol. 4 7,1° An agar diffusion method of antimicrobial susceptibility with a standardized inoculum is recommended. 4,10 Both E. corrodens isolates cultured from the patients described herein were susceptible to
Fig. 4 (Hemady and associates). Case 2. Computed tomography of the orbits (axial plane, with contrast) shows resolution of the left orbital abscess and left ethmoidal sinusitis.
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Orbital Cellulitis Caused by Eikenella corrodens
ampicillin, chloramphenicol, tetracycline, and cefamandole. Ocular and adnexal infections with £. corrodens are rare. This may not, however, reflect the true incidence of ocular infections with the organism as specific growth requirements, slow growth in culture, and polymicrobial infections make isolation of £. corrodens difficult. In 1979, Schwartz and colleagues 8 were the first to report ocular infections with £. corrodens. In one patient, orbital cellulitis was polymicrobial. The infection was successfully treated with intravenous penicillin but required surgical drainage. The patient also had sinusi tis. In the second patient, orbital cellulitis caused by E. corrodens was the result of an infected prosthesis after orbital exenteration. In 1981 a case of periorbital cellulitis caused by E. corrodens complicating a human bite was de scribed (unpublished data, Schulman, M. F., Bottone, E. T., Raab, E. L., and Odel, } . , "Lid abscess from a human bite," presented as a poster at the American Academy of Ophthal mology meeting, November 1981). In 1983, Harris 9 described a patient with a subperiosteal abscess caused by a polymicrobial infection including £. corrodens. The patient lost light perception despite treatment with penicillin and nafcillin intravenously and orbital drain age. The patient also had sinusitis. In a report of 33 cases of infection with £. corrodens in a general hospital, Stoloff and Gillies 7 identified three cases of ocular infections. One patient developed a polymicrobial dacryocystitis in an eye with a prosthesis. Two patients developed conjunctivitis; one was unilateral and polymi crobial, the other bilateral in which £. corrodens was the only isolate. Dua and associates 11 described a patient with a recurrent lacrimai abscess secondary to trauma from which E. corrodens and Haemophilus influenzile were iso lated. Klein, Couch, and Thompson 10 described two patients with ocular infections caused by £. corrodens. One developed a corneal ulcer sec ondary to trauma that responded to fortified topical tobramycin; £. corrodens was the sole isolate. The second patient developed endophthalmitis two days after repair of a penetrat ing corneal injury. Vitreous cultures grew £. corrodens among other organisms. Treatment consisted of vitrectomy, intravitreous, intrave nous, and fortified topical cefazolin and gentamicin, and oral prednisone. Eikenella corrodens was the only organism isolated from Case 2 in our study; this was the
587
third reported case in which £. corrodens was the sole isolate in an ocular infection. 710 These data confirm that £. corrodens may be an ocular pathogen, alone or as part of polymicrobial infections, in young, immunocompetent indi viduals. Ocular infections with £. corrodens usually follow trauma or sinusitis. 7,81011 In our patients sinusitis may have eroded into the orbit, lead ing to the development of a subperiosteal ab scess and orbital cellulitis. A subperiosteal ab scess is an advanced stage of orbital cellulitis requiring prompt treatment as visual loss and extension into the central nervous system may follow.1213 Because ocular and adnexal infec tions with E. corrodens tend to be rapidly pro gressive, treatment should be aggressive; intra venous antibiotics, surgical drainage, and prolonged hospitalization were required in both of our patients. Eikenella corrodens may cause ocular and ad nexal infections, alone or as part of polymicro bial infections, in healthy individuals of all ages. The organism must be suspected in cases of orbital cellulitis especially in the presence of sinusitis and evidence of a subperiosteal ab scess. Efforts should be made to culture E. corrodens from patients with orbital cellulitis as the actual rate of infection with this organism may be higher than that deduced from the current literature. We suggest the use of an antibiotic effective against E. corrodens, such as ampicillin, in the initial management of orbital cellulitis.
References 1. Henriksen, S. D.: Studies in gram-negative an aerobes. II. Gram-negative rods with spreading colo nies. Acta Pathol. Microbiol. Scand. 25:368, 1948. 2. Eiken, M.: Studies on an anaerobic, rod-shaped, gram-negative, microorganism: Bacteroides corrodens. Acta Pathol. Microbiol. Scand. 43:404, 1958. 3. Marsden, H. B„ and Hyde, W. A.: Isolation of Bacteroides corrodens from infections in children. J. Clin. Pathol. 24:117, 1971. 4. Dorff, J. G., Jackson, L. J., and Rytel, M. W.: Infections with Eikenella corrodens. A newly recog nized human pathogen. Ann. Intern. Med. 80:305, 1974. 5. Suwanagool, S., Rothkopf, M. M., Smith, S. M., LeBlanc, D., and Eng, R.: Pathogenicity of Eikenella corrodens in humans. Arch. Intern. Med. 143:2265, 1983. 6. Tami, T. A., and Parker, G. S.: Eikenella cor-
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rodens. An emerging pathogen in head and neck infections. Arch. Otolaryngol. 110:752, 1984. 7. Stoloff, A. L., and Gillies, M. L.: Infections with Eikenella corrodens in a general hospital. A report of 33 cases. Rev. Infect. Dis. 8:50, 1986. 8. Schwartz, H., Baskin, M. A., Ilkiw, A., and LeBeau, L.: An unusual organism causing orbital cellulitis. Br. J. Ophthalmol. 67:710, 1979. 9. Harris, G. J.: Subperiosteal abscess of the orbit. Arch. Ophthalmol. 101:751, 1983. 10. Klein, B., Couch, J., and Thompson, ].: Ocular infections associated with Eikenella corrodens. Am. J. Ophthalmol. 109:127, 1990.
November, 1992
11. Dua, H. S., Paterson, A., Smith, F. W., Scott, G. B., and Forrester, J. V.: Recurrent abscess caused by Eikenella corrodens. Am. J. Ophthalmol. 106:237, 1988. 12. Brill, C. B., Pearlstein, L. S., Kaplan, M., and Mancali, E.: CNS infections caused by Eikenella corrodens. Arch. Neurol. 39:431, 1982. 13. Eustis, H. S., Armstrong, D. C., Buncic, J. R., and Morin, J. D.: Staging of orbital cellulitis in chil dren. Computerized tomography characteristics and treatment guidelines. J. Pediatr. Ophthalmol. Stra bismus 23:246, 1986.
OPHTHALMIC MINIATURE
Now, on very dark nights, light is a deadly enemy to piloting; you are aware that if you stand in a lighted room, on such a night, you cannot see things in the street to any purpose; but if you put out the lights and stand in the gloom you can make out objects in the street pretty well. So, on very dark nights, pilots do not smoke; they allow no fire in the pilot-house stove, if there is a crack which can allow the least ray to escape; they order the furnaces to be curtained with huge tarpaulins and the skylights to be closely blinded. Then n o light whatever issues from the boat. Mark Twain, Life on the Mississippi New York, Bantam Books, 1988, p . 57
Etkenella corrodens is a gram-negative, facultative anaerobic bacillus with specific culture and growth requirements and unusual antibacterial susceptibilities. It has only recently been recognized as a human pathogen. Ocular and adnexal infections with this organism are rare especially in children. We treated two children with orbital cellulitis caused by E. corrodens. One was an 8-year-old boy; the other was an 11-year-old girl. Orbital cellulitis in both patients occurred after an upper respiratory tract infection. Sinusitis and a subperiosteal abscess were present in both patients. Etkenella corrodens and Streptococcus viridans were isolated from the boy; E. corrodens was the sole isolate in the girl. Intravenous ampicillin, prolonged hospitalization, and surgical drainage of the orbit were required to control the infection in both patients. Etkenella corrodens must be considered in the differential diagnosis of orbital cellulitis in children, and ophthalmologists must become familiar with the characteristics of this peculiar organism.
EiiKENELLA CORRODENS is a slow-growing facul tative, anaerobic, gram-negative bacillus that was first described in 1948 by Henriksen. 1 It was thoroughly characterized in 1958 by Eiken (after whom the organism was named). 2 Etkenella corrodens is part of the normal flora of the oral cavity, the nasopharynx, and the upper respiratory, gastrointestinal, and genitourinary tracts.3·4 The organism usually participates in polymicrobial infections of the head, neck, and viscera. 37 Ten cases of ocular and adnexal infec-
Accepted for publication Aug. 4, 1992. From the Department of Ophthalmology (Drs. Hemady, Zimmerman, and Katzen), University of Mary land School of Medicine, Baltimore, Maryland; a n d the Krieger Eye Institute (Dr. Karesh), Sinai Hospital of Baltimore, Maryland. Reprint requests to Ramzi Hemady, M.D., University of Maryland Hospital, Department of Ophthalmology, 22 S. Greene St., Baltimore, MD 21201.
584
tions with E. corrodens have been published: three with orbital cellulitis, 8 · 9 two with conjunc tivitis, 7 and one each with corneal ulcer,10 endophthalmitis, 10 dacryocystitis, 7 periorbital cel lulitis (unpublished data, Schulman, M. F., Bottone, E. } . , Raab, E. L., and Odel, J., "Lid abscess from a human bite," presented as a poster at the American Academy of Ophthal mology meeting, November 1981), and recur rent lacrimai abscess. 11 We treated two children with orbital cellulitis caused by E. corrodens.
Case Reports Case 1 An 8-year-old boy was seen on Dec. 11, 1989, because of a four-day history of gradually in creasing redness of the right eye, eyelid swell ing and tenderness, and headache. He had been treated with gentamicin sulfate eyedrops every four hours and amoxicillin, 375 mg every eight hours orally for three days. Ocular history dis closed anisometropic amblyopia of the right eye, successfully treated with patching and spectacles when the boy was 4 years old. Medi cal history disclosed asthma, sinusitis, and multiple allergies. On examination, visual acuity in each eye was 20/20. The right eye was 6 mm proptotic, with severely edematous, tense, and tender eyelids. Ocular motility was markedly restrict ed in all directions of gaze. Pupils reacted normally to light, and ophthalmoscopy showed a normal fundus. The left eye was normal. Temperature was 100.1 F, total white blood cell count was 12,300 cells/mm 3 , and erythrocyte sedimentation rate was 117 m m / h r . The patient was admitted to the hospital where chloramphenicol sodium succinate, 680 mg every six hours, and nafcillin sodium, 750 mg every four hours, were begun intravenous ly. Gentamicin sulfate eyedrops, every four hours topically, were also begun. Computed tomographic scan of the head and orbits (with contrast) showed a subperiosteal abscess along
© A M E R I C A N JOURNAL O F OPHTHALMOLOGY 114:584-588, NOVEMBER, 1992
Vol. 114, No. 5
Orbital Cellulitis Caused by Eikenella corrodens
the medial wall of the right orbit, and sinusitis of the right maxillary, ethmoid, and sphenoid sinuses. The cerebrospinal fluid was normal. On Dec. 12, 1989, the subperiosteal abscess was surgically drained to release purulent fluid, and an ethmoidectomy and nasal antrostomy were performed via an anterior orbitotomy ap proach. Eikenella corrodens and Streptococcus viridans grew from cultures of the drained fluid. Chloramphenicol and nafcillin were subse quently discontinued, and ampicillin, 200 m g / kg of body weight/day intravenously, was be gun. Steady improvement followed (confirmed by computed tomography on Dec. 19, 1989). Twelve days postoperatively, however, the right lower eyelid became swollen, and an abscess formed that drained spontaneously; cultures grew E. corrodens. Fifteen days after admission, most signs of infection had resolved, ampicillin was discontinued, oral amoxicillin, 250 mg ev ery eight hours was begun, and the patient was discharged from the hospital. Total white blood cell count was 7,600/mm s and erythrocyte sed imentation rate was 57 m m / h r . The patient was last seen on April 17, 1990, at which time visual acuity was R.E.: 20/25 and L.E.: 20/20. Extraocular motility was normal and proptosis was absent. Case 2 An 11-year-old girl was seen on July 23, 1991, because of headache, fever, and periocular swelling of the left side of two days' dura tion. One week previously, she had suffered from an upper respiratory tract infection. The patient denied history of trauma or sinusitis. Ocular and medical histories were otherwise noncontributory. On examination, visual acuity was R.E.: 2 0 / 20 and L.E.: 20/30. The left eyelids were se verely edematous, and diffuse chemosis and conjunctival injection were present (Fig. 1). The globe was 5 mm proptotic and frozen without any extraocular motility. The pupils, posterior segment, and the right eye were normal. Temp erature was 101.4 F and white blood cell count was 13,300/mm 3 . The patient was admitted to the hospital where clindamycin phosphate, 600 mg every eight hours intravenously, ceftriaxone, 2 g every 12 hours intravenously, and neomycin sulfate-bacitracin zinc-polymyxin B sulfate and erythromycin ophthalmic oint ments, every four hours, were begun topically. Computed tomographic scan of the head and orbits (with contrast) disclosed exophthalmos, a subperiosteal abscess of the right medial or-
585
Fig. 1 (Hemady and associates). Case 2. Marked periocular edema of the left eye. bital wall pushing the globe laterally and interi orly, and right ethmoid and maxillary sinusitis (Fig. 2). On July 23, 1991, the patient under went a right external ethmoidectomy, inferior meatus nasal antrostomy, and drainage of the subperiosteal abscess. On July 25, 1991, £. corrodens grew from cultures of the drained fluid. Clindamycin phosphate was discontinued and ampicillin sodium/sulbactam sodium, 1.5 g every six hours intravenously, was begun. The patient's condition did not improve, however, and repeat computed tomography showed per sistence of the subperiosteal abscess (Fig. 3). On July 26, 1991, the patient underwent en largement of the right external ethmoidectomy and inferior nasal meatus, repeat nasal antros tomy, and repeat incision of left orbital perios teum. She improved rapidly thereafter. By Aug. 1, 1991, she had recovered visual acuity of 20/20 and full ocular motility, and proptosis had resolved (Fig. 4). Topical antibiotics were discontinued. Ampicillin/sulbactam and ceftriaxone were discontinued on Aug. 5, 1991, and amoxicillin/clavulanate potassium, 500 mg every eight hours for 14 days, was begun. The patient was discharged from the hospital on Aug. 6,1991, at which time she was afebrile and her white blood cell count was 10,600/mm 3 . When she was last seen on Sept. 19, 1991, visual acuity in each eye was 20/20, proptosis was absent, and extraocular motility was nor mal.
Discussion Eikenella corrodens is part of the normal flora of the oral cavity, nasopharynx, upper respira-
586
AMERICAN JOURNAL OF OPHTHALMOLOGY
November, 1992
Fig. 3 (Hemady and associates). Case 2. Computed tomography of the orbits (axial plane, with contrast) shows persistence of the subperiosteal abscess of the left orbit after the first orbital drainage procedure. Fig. 2 (Hemady and associates). Case 2. Computed tomography of the orbits (axial plane, with contrast) shows a left subperiosteal abscess of the medial orbital wall and ethmoidal sinusitis. tory tract, bowel, and urogenital tract, 3 · 4 but not the conjunctiva, 11 in humans. The organism is a newly recognized human pathogen that has been involved in infections of the central nerv ous system, head and neck, skin and soft tissue, and respiratory system. 4 7 Sinusitis caused by £. corrodens has been associated with central nervous system complications including subdural empyema and cerebral abscess. 12 Infections with £. corrodens usually follow contamination through oral secretions or ruptured viscera, more commonly occur in elderly or immunocompromised patients, and are usually part of polymicrobial infections.4"7 Eikenella corrodens requires specific laborato ry growth conditions: blood or chocolate agar incubated with 5% to 15% C0 2 at 35 to 37 C and 100% humidity anaerobically for a minimum of 72 hours. The colonies are typically small, gray, and pitting with three distinct growth zones. A bleach-like odor is common. Clindamycin (0.5 ìg/ml) may be added to the growth medium to facilitate isolation of the organism.4,7,10 Eikenella corrodens is commonly resistant to many broad-spectrum antibiotics such as the
aminoglycosides and penicillinase-resistant penicillins, and to clindamycin and metronidazole. The organism is usually susceptible to penicillin, ampicillin, vancomycin, erythromycin, and chloramphenicol. 4 7,1° An agar diffusion method of antimicrobial susceptibility with a standardized inoculum is recommended. 4,10 Both E. corrodens isolates cultured from the patients described herein were susceptible to
Fig. 4 (Hemady and associates). Case 2. Computed tomography of the orbits (axial plane, with contrast) shows resolution of the left orbital abscess and left ethmoidal sinusitis.
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Orbital Cellulitis Caused by Eikenella corrodens
ampicillin, chloramphenicol, tetracycline, and cefamandole. Ocular and adnexal infections with £. corrodens are rare. This may not, however, reflect the true incidence of ocular infections with the organism as specific growth requirements, slow growth in culture, and polymicrobial infections make isolation of £. corrodens difficult. In 1979, Schwartz and colleagues 8 were the first to report ocular infections with £. corrodens. In one patient, orbital cellulitis was polymicrobial. The infection was successfully treated with intravenous penicillin but required surgical drainage. The patient also had sinusi tis. In the second patient, orbital cellulitis caused by E. corrodens was the result of an infected prosthesis after orbital exenteration. In 1981 a case of periorbital cellulitis caused by E. corrodens complicating a human bite was de scribed (unpublished data, Schulman, M. F., Bottone, E. T., Raab, E. L., and Odel, } . , "Lid abscess from a human bite," presented as a poster at the American Academy of Ophthal mology meeting, November 1981). In 1983, Harris 9 described a patient with a subperiosteal abscess caused by a polymicrobial infection including £. corrodens. The patient lost light perception despite treatment with penicillin and nafcillin intravenously and orbital drain age. The patient also had sinusitis. In a report of 33 cases of infection with £. corrodens in a general hospital, Stoloff and Gillies 7 identified three cases of ocular infections. One patient developed a polymicrobial dacryocystitis in an eye with a prosthesis. Two patients developed conjunctivitis; one was unilateral and polymi crobial, the other bilateral in which £. corrodens was the only isolate. Dua and associates 11 described a patient with a recurrent lacrimai abscess secondary to trauma from which E. corrodens and Haemophilus influenzile were iso lated. Klein, Couch, and Thompson 10 described two patients with ocular infections caused by £. corrodens. One developed a corneal ulcer sec ondary to trauma that responded to fortified topical tobramycin; £. corrodens was the sole isolate. The second patient developed endophthalmitis two days after repair of a penetrat ing corneal injury. Vitreous cultures grew £. corrodens among other organisms. Treatment consisted of vitrectomy, intravitreous, intrave nous, and fortified topical cefazolin and gentamicin, and oral prednisone. Eikenella corrodens was the only organism isolated from Case 2 in our study; this was the
587
third reported case in which £. corrodens was the sole isolate in an ocular infection. 710 These data confirm that £. corrodens may be an ocular pathogen, alone or as part of polymicrobial infections, in young, immunocompetent indi viduals. Ocular infections with £. corrodens usually follow trauma or sinusitis. 7,81011 In our patients sinusitis may have eroded into the orbit, lead ing to the development of a subperiosteal ab scess and orbital cellulitis. A subperiosteal ab scess is an advanced stage of orbital cellulitis requiring prompt treatment as visual loss and extension into the central nervous system may follow.1213 Because ocular and adnexal infec tions with E. corrodens tend to be rapidly pro gressive, treatment should be aggressive; intra venous antibiotics, surgical drainage, and prolonged hospitalization were required in both of our patients. Eikenella corrodens may cause ocular and ad nexal infections, alone or as part of polymicro bial infections, in healthy individuals of all ages. The organism must be suspected in cases of orbital cellulitis especially in the presence of sinusitis and evidence of a subperiosteal ab scess. Efforts should be made to culture E. corrodens from patients with orbital cellulitis as the actual rate of infection with this organism may be higher than that deduced from the current literature. We suggest the use of an antibiotic effective against E. corrodens, such as ampicillin, in the initial management of orbital cellulitis.
References 1. Henriksen, S. D.: Studies in gram-negative an aerobes. II. Gram-negative rods with spreading colo nies. Acta Pathol. Microbiol. Scand. 25:368, 1948. 2. Eiken, M.: Studies on an anaerobic, rod-shaped, gram-negative, microorganism: Bacteroides corrodens. Acta Pathol. Microbiol. Scand. 43:404, 1958. 3. Marsden, H. B„ and Hyde, W. A.: Isolation of Bacteroides corrodens from infections in children. J. Clin. Pathol. 24:117, 1971. 4. Dorff, J. G., Jackson, L. J., and Rytel, M. W.: Infections with Eikenella corrodens. A newly recog nized human pathogen. Ann. Intern. Med. 80:305, 1974. 5. Suwanagool, S., Rothkopf, M. M., Smith, S. M., LeBlanc, D., and Eng, R.: Pathogenicity of Eikenella corrodens in humans. Arch. Intern. Med. 143:2265, 1983. 6. Tami, T. A., and Parker, G. S.: Eikenella cor-
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OPHTHALMIC MINIATURE
Now, on very dark nights, light is a deadly enemy to piloting; you are aware that if you stand in a lighted room, on such a night, you cannot see things in the street to any purpose; but if you put out the lights and stand in the gloom you can make out objects in the street pretty well. So, on very dark nights, pilots do not smoke; they allow no fire in the pilot-house stove, if there is a crack which can allow the least ray to escape; they order the furnaces to be curtained with huge tarpaulins and the skylights to be closely blinded. Then n o light whatever issues from the boat. Mark Twain, Life on the Mississippi New York, Bantam Books, 1988, p . 57