EDITOR,Ochrobactrum anthropi is a non-fermentative, motile, strictly aerobic, oxidase positive Gram negative bacillus.¹ In 1980, the first case of human infection with O anthropi was described.² Since then, there have been some reports and this bacillus has been considered as a possible cause of opportunistic infection. There are only two reports of O anthropi endophthalmitis, one was metastatic endophthalmitis in a patient with a central venous catheter,³ and the other was after cataract surgery.⁴ We describe a case of unilateral endophthalmitis caused by O anthropi, which was diagnosed after two vitreous surgery procedures.

CASE REPORT
A 64 year old man complained of visual loss in his left eye in January 1998. He was diagnosed with uveitis and treated with oral prednisolone, topical betamethasone and atropine, and subconjunctival injection of dexamethasone. As the inflammation had not resolved, he was transferred to our institution. He had a medical history of bacterial endocarditis caused by Streptococcus haemolyticus in April 1997 and underwent placement of a central venous catheter for 1 month. Mitral valvuloplasty had been performed in October 1997.

His visual acuity was right eye 20/20 and left eye 20/100. The left eye had anterior chamber inflammation with flare (1+) and cells (2+), keratic precipitates, and prominent vitritis with a lobulated white mass. The right eye was normal. A clinical diagnosis of fungal endophthalmitis was made in the left eye. Medication was changed to intravenous fluconazole, topical betamethasone, and subconjunctival injection of dexamethasone, but vitreous haze was still present with this treatment (Fig 1). A pars plana vitrectomy with removal of the lens and intravitreal fluconazole irrigation was performed on 14 April 1998. The next day he had severe pain in his left eye and headache. Left visual acuity reduced to light perception, intraocular pressure was 42 mm Hg, and marked inflammation with hypopyon was observed. As a bacterial endophthalmitis was suspected, he underwent the second vitrectomy on 16 April 1998 with intravitreal imipenem irrigation. Vitreous cultures grew O anthropi. The isolate was sensitive to cefmetazole, cefbuperazone, imipenem, minocycline, levofloxacin, gentamicin, tobramycin, and amikacin, and resistant to ampicillin, piperacillin, cefazolin, cefotiam, flomoxef, and ceftazidime. He was treated with intravenous imipenem, oral minocycline, and ciprofloxacin, successively, and the intraocular inflammation subsided. Four months after the second vitrectomy, his left visual acuity was 20/30.

View larger version (72K): [in this window] [in a new window]   Figure 1   Vitreous haze with a lobulated white mass in the inferior vitreous.

COMMENT
The natural habitat of O anthropi has not yet been established. It is commonly found in environmental and hospital water sources.^1 2 This organism has been isolated from clinical specimens, including blood, urine, faeces, and sputum. Most cases of O anthropi sepsis were reported to relate to indwelling catheters for venous access or other permanent medical devices.^5-7 As for the infectious routes, there are two possibilities in our case. One is contamination during mitral valvuloplasty. Indeed, a lobulated white mass in the vitreous seen before the first vitrectomy (Fig 1) is similar to that in the case of Berman et al.³ In the past, however, O anthropi endophthalmitis occurred within 3 weeks after placement of a central venous catheter.³ Endophthalmitis occurred in our case more than 70 days after the mitral valvuloplasty. Moreover, O anthropi was detected from in the vitreous sample only at the second vitreous procedure. Accordingly, contamination in our case may have been caused during the first vitreous surgery procedure. Bacterial endophthalmitis after vitreous surgery is very rare; its frequency is about 0.2%.^8 9 The main organisms causing endophthalmitis are Pseudomonas aeruginosa, Staphylococcus epidermidis, and S aureus.^8 9 However, one should look out for infections induced by attenuated bacteria such as O anthropi after vitrectomy.