Journal of Microbiology

Research Support, U.S. Gov't, Non-P.H.S.

NOTE] Fosmid Cloning, Nucleotide Sequence, and Characterization of a Beta-Lactamase Gene from Subsurface Isolates: Nurcan Vardar , Gönül Vardar-Schara; J. Microbiol. 2012;50(4):680-683. Published online July 21, 2012; DOI: https://doi.org/10.1007/s12275-012-2139-9

Abstract: A beta-lactamase gene was isolated for the first time from a terrestrial subsurface environment using a combined cultivation and direct cloning strategy. The gene, discovered from 24 m below land surface in Hawaii, was most similar to the penicillinase from Bacillus licheniformis. The resistance gene was confirmed via subcloning and its minimum inhibitory concentration values were measured against several test betalactam antibiotics. This study extends the knowledge on resistance to antimicrobials, which may help the efforts to minimize their future threat.

Research Support, Non-U.S. Gov't

Characterization of Conjugative Plasmids Carrying Antibiotic Resistance Genes Encoding 16S rRNA Methylase, Extended-Spectrum Beta-Lactamase, and/or Plasmid-Mediated AmpC Beta-Lactamase: Hee Young Kang , Jungmin Kim , Sung Yong Seol , Yoo Chul Lee , Je Chul Lee , Dong Taek Cho; J. Microbiol. 2009;47(1):68-75. Published online February 20, 2009; DOI: https://doi.org/10.1007/s12275-008-0158-3

Abstract: In this study, we identified extended-spectrum ß-lactamase (ESBL) and plasmid-mediated AmpC ß-lactamase which were associated with 16S rRNA methylase gene on the conjugative plasmid. Among 82 clinical isolates of Enterobacteriaceae that carry 16S rRNA methylase gene (64 strains, armA, and 18 strains, rmtB), blaSHV-12 was detected either alone or combined with blaDHA-1, blaCTX-M-3, and blaCTX-M-14 in 30 strains carrying armA and 6 strains carrying rmtB. The blaCTX-M-3 was detected in 13 of 64 strains carrying armA but no strains carrying rmtB. Whereas blaCTX-M-14 was detected in 15 of 18 strains carrying rmtB but only 2 of 64 strains carrying armA. Overall, blaSHV-12 and blaCTX-M-14 was the most common ESBL gene which was associated with armA and rmtB, respectively. In addition, we found that blaCTX-M-3 localized with armA on the same IncL/M plasmid and blaCTX-M-14 localized with rmtB on the same IncA/C plasmid. Restriction fragment length polymorphism of conjugative plasmids and pulsed-field gel electrophoresis of genomic DNAs revealed that intercellular horizontal transfer of conjugative plasmid and clonal transmission have been occurred at the same time.

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