emergence of integron borne per1 mediated extended spectrum cephalosporin resistance among nosocomial isolates of gramnegative bacilli background objectives pseudomonas extended resistant per enzymes are rare type of extendedspectrum beta lactamases esbls that confer third generation cephalosporin resistance these are often integron borne and laterally transmitted the aim of the present study was to investigate the emergence of integron borne cephalosporin resistant per1 gene in diverse incompatibility inc group plasmids among gramnegative bacteriamethods a total of 613 consecutive nonduplicate gramnegative bacteria of enterobacteriaceae family and nonfermenting gramnegative bacteria were isolated from different clinical specimens during a period of 18 months for amplification and detection of blaper multiplex pcr was done for understanding the genetic environment of blaper1 integrase gene pcr and cassette pcr 59 be was performed gene transferability experiment was carried out and pcr based replicon typing was performed for incompatibility group typing of plasmids using 18 pairs of primers an inhibitor based method was used for phenotypic detection of intrinsic resistanceresults multiplex pcr and sequencing confirmed that 45 isolates were harbouring blaper1 both class 1 and class 2 integrons were observed among them integrase and cassette pcr 59 be pcr results confirmed that the resistant determinant was located within class 1 integron transformation and conjugation experiments revealed that per1 was laterally transferable and disseminated through diverse inc plasmid type efflux pump mediated carbapenem resistance was observed in all isolates all isolates belonged to heterogenous groupsinterpretation conclusions this study demonstrates the dissemination of cephalosporins resistant integron borne blaper1 in hospital setting in this part of the country and emphasizes on the rational use of third generation cephalosporins to slow down the expansion of this rare type of esbl gene