Molecular characterization of TEM-type beta-lactamases identified in cold-seep sediments of Edison Seamount (south of Lihir Island, Papua New Guinea).
To determine the prevalence and genotypes of beta-lactamases among clones of a metagenomic library from the cold-seep sediments of Edison seamount (10,000 years old), we performed pulse-field gel electrophoresis, antibiotic susceptibility testing, pI determination, and DNA sequencing analysis. Among the 8,823 clones of the library, thirty clones produced beta-lactamases and had high levels of genetic diversity. Consistent with minimum inhibitory concentration patterns, we found that five (16.7%) of thirty clones produced an extended-spectrum beta-lactamase. 837- and 259-bp fragments specific to blaTEM genes were amplified, as determined by banding patterns of PCR amplification with designed primers. TEM-1 was the most prevalent beta-lactamase and conferred resistance to ampicillin, piperacillin, and cephalothin. TEM-116 had a spectrum that was extended to ceftazidime, cefotaxime, and aztreonam. The resistance levels conferred by the pre-antibiotic era alleles of TEM-type beta-lactamases were essentially the same as the resistance levels conferred by the TEM-type alleles which had been isolated from clinically resistant strains of bacteria of the antibiotic era. Our first report on TEM-type beta-lactamases of the pre-antibiotic era indicates that TEM-type beta-lactamases paint a picture in which most of the diversity of the enzymes may not be the result of recent evolution, but that of ancient evolution.
Song
Jae Seok
JS
Department of Biological Sciences, Myongji University, San 38-2 Namdong, Yongin, Kyunggido, 449-728, Republic of Korea.
Jeon
Jeong Ho
JH
Lee
Jung Hun
JH
Jeong
Seok Hoon
SH
Jeong
Byeong Chul
BC
Kim
Sang-Jin
SJ
Lee
Jung-Hyun
JH
Lee
Sang Hee
SH
D015723:Gene Library; D005838:Genotype; D019015:Geologic Sediments / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010219:Papua New Guinea; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics*
D001618:beta-Lactamases