Draft Could the Diversilab ® semi - automated repetitive - sequence - based PCR be an acceptable technique for typing isolates of Pseudomonas aeruginosa ? An answer from our experience and a review of the literature

32 Recently the DiversiLab (DL) system (bioMérieux) was developed as an automated platform that uses 33 rep-PCR technology for standardized, reproducible DNA fingerprinting of bacteria. The purpose of this 34 study was to evaluate the usefulness of DL rep-PCR for typing of Pseudomonas aeruginosa isolates. 35 The performance of DL rep-PCR was compared with that of pulsed-field gel electrophoresis (PFGE) in 36 a prospective multicenter study of patients with ventilator-associated pneumonia due to P. aeruginosa 37 conducted in 3 intensive care units during a 31-month period. In total, 203 P. aeruginosa isolates from 38 66 patients, from whom at least 2 consecutive respiratory samples each were collected more than 48 h 39 apart, were typed using DL rep-PCR; 40 isolates (corresponding to 20 patients) were also typed using 40 PFGE of SpeI-digested DNA. The typeability was 100% with DL rep-PCR and 95% with PFGE. The 41 discriminatory power was close for DL rep-PCR and for PFGE (Simpson’s index of diversity of 0.901 42 and 0.947, respectively). An insufficient agreement between DL rep-PCR and PFGE typing results was 43 observed for the 40 selected isolates (adjusted Rand coefficient of 0.419), due mostly to isolates of the 44 same DL rep-PCR type but of different PFGE types (adjusted Wallace coefficients of DL rep-PCR with 45 PFGE of 0.306, and of PFGE with DL rep-PCR of 0.667). Considered together with published data, DL 46 rep-PCR results should be interpreted with caution for the investigation of outbreaks caused by 47 P. aeruginosa, and evaluated in conjunction with epidemiological data. 48 49