Evaluation of Propionibacterium acnes isolates using contour-clamped homogeneous electric field gel electrophoresis

Contour-clamped homogeneous electric field electrophoresis was performed to compare strains of Propionibacterium acnes isolated from patients with chr onic postoperative endophthalmitis. Propionibacterium acnes isolates were o btained from the vitreous humor of nine patients with chronic postoperative endophthalmitis following cataract surgery. In two of the patients, P. acn es isolates were also obtained from the aqueous humor as well as from the v itreous humor. Bacterial DNA was digested using NotI and SpeI restriction e ndonucleases. The DNA fragments were then subjected to contour-clamped homo geneous electric field electrophoresis and the DNA banding patterns were an alysed. Eight nonidentical banding patterns were identified among the nine vitreous isolates of P. acnes. In each of the two cases from which aqueous and vitreous isolates were recovered from the same eye, the banding pattern s were identical. Contour-clamped homogeneous electric field electrophoresi s is a powerful method to distinguish P. acnes isolates based on DNA bandin g patterns and could be used in the epidemiological study of clinical proce sses caused by this organism. (C) 1999 Academic Press.