Microbiological study on foreign body and vitreous samples of patients with intraocular foreign body

Objective To evaluate the relationship between the microbiological results of the vitreous humor and those of foreign body specimens in patients with intraocular foreign body (IOFB). Methods Seventy-one patients with an IOFB were included in this descriptive prospective case series. All patients underwent immediate IOFB removal. Vitreous sampling was performed during vitrectomy. Foreign bodies were placed directly into culture media for microbiological study. Results Thirteen (18.3%) patients developed endophthalmitis. The results of microbiological analysis of IOFB and vitreous humor specimens were negative in nine patients and positive in four. Fifty-eight (81.6%) patients with an IOFB had no evidence of endophthalmitis. Among them, seven patients showed positive microbiological results of foreign bodies with no manifestations of endophthalmitis. In five patients, a Staphylococcus epidermidis strain was observed in the culture of the IOFB specimen. Two patients had only positive smear test results of their vitreous humor specimen. Conclusion A correlation appears to be present between the microbiological results of the vitreous humor and IOFB specimens in patients with clinical findings of endophthalmitis but not in patients with a pure IOFB without clinical features of endophthalmitis. This may justify early use of intravitreal and intravenous antibiotics before the development of endophthalmitis.