Detection of methicillin-resistant Staphylococcus aureus in donor eye preservation media by polymerase chain reaction.

To examine contamination of donor eye preservation media with methicillin-resistant Staphylococcus aureus (MRSA), we studied the media to detect specific genes for MRSA by use of the polymerase chain reaction (PCR) method. The materials were 36 samples of donor eye preservation media (EP-II) in which donor eyes had been stored for keratoplasty. Polymerase chain reaction procedures were carried out to simultaneously detect the spa gene, which codes protein A of S. aureus, and the mecA gene, which codes penicillin-binding protein-2' contributing resistance to methicillin. Along with PCR analyses, the preservation media was examined by conventional culture methods to determine bacteriologic contamination. The PCR analyses of the 36 samples revealed that both the spa and the mecA genes were positive in five samples, only the spa gene was positive in two, and only the mecA gene was positive in two. The conventional culture of the media showed positive for MRSA in 5 samples, methicillin-susceptible S. aureus (MSSA) in 2, methicillin-susceptible coagulase-negative staphylococci (MS-CNS) in 4, and methicillin-resistant coagulase-negative staphylococci (MR-CNS) in 2 of the 36 samples. The results of PCR coincided well with those of conventional bacteriologic culture. Polymerase chain reaction analysis for spa and mecA genes is useful in detecting contamination of donor eye preservation media by MRSA, MSSA, MR-CNS, or MS-CNS in a shorter time than by conventional culture.