Journal of Microbiology

Research Support, Non-U.S. Gov'ts

Serotype Distribution and β-Lactam Resistance in Haemophilus influenzae Isolated from Patients with Respiratory Infections in Korea: Songmee Bae , Jaehoon Lee , Eunah Kim , Jaehwa Lee , Jaeyon Yu , Yeonho Kang; J. Microbiol. 2010;48(1):84-88. Published online March 11, 2010; DOI: https://doi.org/10.1007/s12275-009-0212-9

Abstract: Haemophilus influenzae is a frequent causative bacterial pathogen of respiratory tract infections. Resistance to β-lactam antibiotics has been a significant clinical problem in treatment for H. influenzae respiratory infections. This study describes the serotype, antibiotic resistance and distribution of TEM-1 or ROB-1 β-lactamase in H. influenzae isolates from local private hospitals from 2002 to 2004. Among the 100 H. influenzae respiratory isolates, only 7% were identified as serotypes a, b, e, and f, with the remaining 93% being nontypeable. Resistance to ampicillin, cefaclor, and tetracycline was 57%, 46%, and 16%, respectively. All strains were susceptible to azithromycin and ciprofloxacin, whereas amoxicillin/clavulanate, cefotaxime, and imipenem exhibited reduced susceptibilities of 99%, 99%, and 91%, respectively. All 57 ampicillinresistant strains (minimum inhibitory concentration, MIC≥4 µg/ml) were β-lactamase-positive and possessed the TEM-1 type β-lactamase. One β-lactamase-positive amoxicillin/clavulanate-resistant isolate that was resistant to ampicillin (MIC>128 µg/ml) had the TEM-1 type β-lactamase and not susceptible to cefaclor and cefotaxime. Analysis of penicillin binding protein 3 revealed six residues (Asp-350, Met-377, Ala-502, Asn-526, Val-547, and Asn-569)that were substituted by Asn, Ile, Val, Lys, Ile, and Ser, respectively.

Molecular Characterization of TEM-type [beta]-Lactamases Identified in Cold-Seep Sediments of Edison Seamount (South of Lihir Island, Papua New Guinea): Jae Seok Song , Jeong Ho Jeon , Jung Hun Lee , Seok Hoon Jeong , Byeong Chul Jeong , Sang-Jin Kim , Jung-Hyun Lee , Sang Hee Lee; J. Microbiol. 2005;43(2):172-178.; DOI: https://doi.org/2165 [pii]

Abstract: 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 bla_TEM 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.

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