Center-to-center reproducibility of P-aeruginosa genotype determination bypulsed-field gel electrophoresis.

The increasing hospital-to-hospital transmission of multiple drug-resistant bacteria is a major concern for bacteriology laboratories involved in noso comial infection control. The interlaboratory reproducibility of pulsed-fie ld gel electrophoresis (PFGE) for Pseudomonas aeruginosa typing was evaluat ed by asking four hospital laboratories (two in Lyon, one in Brest, and one in Marseille) to study 11 P. aeruginosa isolates, some of which were epide miologically related, and the reference strain ATCC 27853. Two laboratories used the Genepath(R) system, one the Chef DR II(R), system, and one the Ch ef Mapper(R) system, Bio-Rad, restriction/Spe I. Profiles were read visuall y and by computerized comparison of restriction band molecular weights (Tax otron(R), software, PAD Grimont, Pasteur Institute, Paris, France). These t wo methods led to similar epidemiological conclusions. However, centralizat ion of the data showed poor center-to-center reproducibility due to inadequ ate standardization of the procedure.