Objective To identify the ESBL gene in a
Klebsiella pneumoniae strain isolated from one patient in Huashan Hospital, Shanghai.
Methods The bla TEM, bla SHV, and bla CTX-M in the transconjugant from the
Klebsiella pneumoniae isolate were amplified by PCR respectively. The PCR products were cloned into pHSG398 vector. The antibiotic susceptiblity and β-lactamases activity of the clone strain were tested. The PCR products were also directly sequenced and analyzed. Results The β-lactamase gene from K99-1029 were identified as TEM-1, SHV-12, and CTX-M-3 type respectively; The clone strain producing CTX-M-3 or SHV-12 was resistant to most β-lactams, SHV-12 or CTX-M-3 were active to hydrolyze most β-lactams and CTX-M-3 were much more active to hydrolyze cefotaxime than to ceftazidine; The clone strain producing TEM-1 was only resistant to ampicillin and piperacillin, TEM-1 was active to hydrolyze ampicillin and piperacillin. Conclusions The clinical isolate of Klebsiella
Pneumoniae K99-1029 isolated from patients in Huashan Hospital, Shanghai, produced SHV-12, CTX-M-3 ESBLs and β-lactamase TEM-1 ESBLs simultaneously, which caused this isolate resistant to most β-lactams.