RT Journal Article
SR Electronic
T1 β-Lactamases in <em>Shigella flexneri</em>Isolates from Hong Kong and Shanghai and a Novel OXA-1-Like β-Lactamase, OXA-30
JF Antimicrobial Agents and Chemotherapy
JO Antimicrob. Agents Chemother.
FD American Society for Microbiology
SP 2034
OP 2038
DO 10.1128/AAC.44.8.2034-2038.2000
VO 44
IS 8
A1 Siu, L. K.
A1 Lo, J. Y. C.
A1 Yuen, K. Y.
A1 Chau, P. Y.
A1 Ng, M. H.
A1 Ho, P. L.
YR 2000
UL http://aac.asm.org/content/44/8/2034.abstract
AB Ninety-one ampicillin-resistant Shigella flexneristrains from Hong Kong and Shanghai were studied for production of β-lactamases. TEM-1-like and OXA-1-like enzymes were identified in 21 and 79% of the strains, respectively, by isoelectric focusing (IEF). No difference in the pattern of β-lactamase production was found between strains from Hong Kong and Shanghai. Four ribotypes were detected. Over 88% of OXA-producing strains had the same ribotype. All TEM-1-like strains harbored a plasmid which hybridized positively with thebla TEM probe. Total DNA from OXA-1-like strains failed to hybridize or only hybridized weakly with an OXA probe. The OXA resistance was not transferable. OXA-1-like enzymes exhibited substrate and inhibition profiles similar to that of OXA-1 and were shown to have a pI of 7.3 by further IEF using a narrow-range ampholine gel. The gene encoding the OXA-1-like enzyme from one isolate (CH-07) was cloned, sequenced, and found to differ from bla OXA-1 at codon 131 (AGA→GGA; Arg to Gly), resulting in the novel designation OXA-30. The predominance of OXA-type enzymes in ampicillin-resistantS. flexneri suggests host preference for specific β-lactamases.