3.5 Conjugative transfer and stability of plasmids harboring MDR
regions
Transconjugants were obtained from mating experiments withKlebsiella pneumoniae M297-1 donors, in E. coli J53
recipients, at rates of 10−5 to 10−6transconjugants per recipient cell. All 13 putative transconjugants
tested were found to be the recipient background species and to be
β-lactamase positive by antimicrobial susceptibility testing. Notably, 8
of the 13 transconjugants were resistance to sulfamethoxazole,
chloramphenicol and tetracycline , which was suggested to be
transconjugants carrying with pM297-1.2 (Table 3). The another 4 strains
were not resistant to the sulfamethoxazole, chloramphenicol andtetracycline (Table 3),which was considered to be transconjugants
carried pM297-1.1. All positive transconjugants colonies tested,
resistance to cefotaxime , remained detectable throughout the
6-day passage experiment, even in the absence of antibiotic selection.
Therefore, it was confirmed that the two plasmids carried byKlebsiella pneumoniae M297-1 had stronger transferability and
stability in new host bacteria.