• Korean Journal of Veterinary Research
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• v.48 no.3
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• pp.259-265
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• 2008

This study was conducted to investigate incidence of extended-spectrum ${\beta}$-lactamase (ESBL) producing strains and characteristics of ESBL gene in pathogenic Escherichia coli isolated from poultry during the period from April 2003 to December 2005 in Korea. Among 203 isolates, 4 isolates (3 from broilers and 1 from layer) were confirmed as ESBL producing strains by double disk synergy test, polymerase chain reaction and sequencing for ${\beta}$-lactamase genes. $bla_{CTX-M-15}$ and $bla_{CMY-2}$ were detected in these 4 isolates and were transferred to recipient by conjugation, respectively. Also, these ESBL producing strains were associated with multiple drug resistance. In conclusion, these results exhibit incidence of CTX-M and CMY-2 ${\beta}$-lactamase in pathogenic E coli from poultry in Korea, and clinically important meaning in human. And they also suggest the needs for rapid and broad surveillance to monitor ESBL genes and R plasmid transferring resistant gene in poultry.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.125-130
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• 2006

The emergence of extended spectrum ${\beta}$-lactamase producing bacteria is causing very serious problems in Korea. Although there have been many reports about these bacteria Isolated from patients and clinical specimens, there is no report of extended spectrum ${\beta}$-lactamase producing organisms isolated from natural environment in Korea. This study was conducted to investigate the biological characteristics and extended spectrum ${\beta}$-lactamase types of eighteen strains of extended spectrum ${\beta}$-lactamase producing Klebsiella pneumoniae and Escherichia coli isolated from a slaughterhouse in Pusan in Korea during 2002 to 2004. Extended spectrum ${\beta}$-lactamases were identified by double-disk synergy test, conjugation, isoelectric focusing values and gene sequencing. Eight strains of Klebsiella pneumoniae and two strains of Eschericha coli were isolated kom pigs and transferred extended spectrum ${\beta}$-lactamase genes to recipient Escherichia coli J53 (sodium azide resistant and ceftazidime senstive) strain by conjugation. The conjugants of extended spectrum ${\beta}$-lactamase genes were alignments and translated to amino acids by BCM and NCBI blast. Eight conjugants of Klebsiella pneumonae were typed TEM-52, and two strains of Escherichia coli, SHV-12, but CMY-1 type were not detected in this study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.637-641
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• 2010

The antibiotics-resistance profiles of 28 strains of Vibrio parahaemolyticus isolated from seawater were investigated. All of the strains studied were resistant to ampicillin (100%), but susceptible to 12 other antibiotics. The minimum inhibitory concentration (MIC) of V. parahaemolyticus to ampicillin was as high as $1,024-2,048\;{\mu}g{\cdot}mL^{-1}$. The phenotype of strain 8 changed from ampicillin-resistant to susceptible with an in-frame deletion mutant of VPA0477, a putative ${\beta}$-lactamase gene, and the MIC for ampicillin of the mutant strain was $1{\mu}g{\cdot}mL^{-1}$. In conclusion, our findings suggest that the VPA0477 gene acts as a ${\beta}$-lactamase in ampicillin-resistant V. parahaemolyticus strains.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.369-374
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• 1996

The ${\beta}$-lactamase inhibitory protein (BLIP) produced by Streptomyces exfoliatus SMF19 was purified(33 kDa) and the N-terminal amino acid sequence was determined as NH2-ATSVVAWGGNND. Genomic DNA library of S. exfoliatus SMF19 was constructed in pWE15 and recombinants harbouring the corresponding gene were selected by colony hybridization to the mixture of 36-mer oligonucleotide designed from the N-terminal amino acid sequence. The corresponding gene (bliX) was isolated on a 4-kb ApaI fragment of S. exfoliatus SMF19 chromosomal DNA and then sequenced. The bliX consisting of 1, 119bp encoded a mature protein with a deduced amino acid sequence of 342 residues and also encoded a 40-amino-acid signal sequence. No significant sequence similarity to bliX was found by pairwise comparison using various protein and nucleotide sequences.

• Journal of Life Science
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• v.19 no.12
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• pp.1718-1723
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• 2009

In this study, we characterized extended-spectrum $\beta$-lactamase (ESBL)-producing Enterobacteriaceae isolated from clinical specimens in Korea and found two strains harboring plasmid-mediated $bla_{SHV-11}$, Klebsiella pneumoniae. First, the isolates were detected using the Vitek system and confirmed by the double-disk synergy test. The classification of gene coding for ESBL was also performed by polymerase chain reactions and followed by DNA sequencing. The transmission of genes was confirmed by transconjugation and transformation. Resistant expression of transformants was determined by broth microdilution minimal inhibitory concentration test. Genotypic analysis revealed that one strain harbored the $bla_{TEM-1}$, $bla_{SHV-11}$ and $bla_{CTX-M-15}$ and the other strain harbored the $bla_{SHV-11}$ and $bla_{CTX-M-15}$. They showed high resistance to oxyiminocephalosphorins (3rd-generation cephalosporins), while the transformant containing only $bla_{SHV-11}$ did not show any resistance to the antibiotics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.1
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• pp.20-25
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• 2009

Thirty-eight Vibrio spp. were isolated from the sea waters harvested from the 22 stations located on the west coast of the Korean peninsula in September 2006. The isolates consisted of V. parahaemolyticus (n=21), V. alginolyticus (n= 16) and V. cholerae non-01 (n=1), among which 35 isolates displayed resistance against two of the tested antibiotics. Among the 38 isolates, 18 isolates exhibited multi-drug resistance against more than four 4 antibiotics. In particular, minimum inhibitory concentration $(MIC)_{50}$ and $MIC_{90}$ of ampicillin-resistant isolates were as high as $2,048{\mu}g{\cdot}mL^{-1}$ and $4,096{\mu}g{\cdot}mL^{-1}$ respectively. $\beta$-lactamase production was examined to analyze the ampicillin-resistance. Some Vibrio spp. isolates produced $\beta$-lactamase, however antibiotics resistance pattern and $\beta$-lactamase production were not clearly related to each other. A genetic relationship between resistance and gene expression was confirmed in the ampicillin-resistant isolates.

• Journal of the Korean Applied Science and Technology
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• v.39 no.6
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• pp.916-923
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• 2022

Water samples were collected from three spots(Namcheon, Changwoncheon and Cheongwoonji) in Changwon and genomic DNA was isolated from them. Quantitative PCR was performed with the isolated DNA as template and primers targeting five different class A extended-spectrum beta-lactamase(ESBL) genes(bla_OXA-1, bla_SHV, bla_TEM, bla_CTX-M-1, bla_CTX-M-9). The number of total ESBL genes from each sample showed large variations between each sample. Thirty nanograms of DNA from Namcheon contained 1.93×10⁶ copies of ESBL genes whereas the same amount of DNA from Changwoncheon contained 1.47×10⁵ copies of ESBL genes. However, the same amount of DNA from Cheongwoonji pond contained only 9.5×10³ copies of ESBL genes. The ratio of each ESBL genes showed little difference between Namcheon river and Changwoncheon river, but DNA from Cheongwoonji pond showed a large difference from the rest. bla_OXA-1 gene was present at 65.3%, and bla_CTX-M-1 gene 33.6% for Namcheon comprising together almost 99%. bla_OXA-1 gene was present at 64.1%, and bla_CTX-M-1 gene 19.1% for Changwoncheon comprising together over 83%. bla_CTX-M-1 gene was present at 87.5% and bla_CTX-M-9 genes 9.8% for Cheongwoonji, a pond which is a closed and isolated environment.

• Journal of Life Science
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• v.22 no.9
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• pp.1268-1276
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• 2012

The emergence and dissemination of carbapenem-resistant bacteria have resulted in limitations of antibiotic treatment and potential outbreaks of metallo-${\beta}$-lactamase (MBL) producing Pseudomonas aeruginosa resistant to carbapenems. In this study, we conducted molecular characterization of the MBL genes of the ${\beta}$-lactam drug-resistant P. aeruginosa and prepared basic data for treatment and prevention of proliferation of antimicrobial-resistant bacterial infections. Forty-two P. aeruginosa isolates of 254 were resistant to imipenem or meropenem. Among the 42 isolates, 28 isolates were positive for the Hodge test, and 23 isolates were positive for the EDTA-disk synergy test (EDST). MBLs were detected in 59.5% (25/42) of P. aeruginosa isolates. Eight isolates harbored $bla_{IMP-6}$, whereas 17 isolates harbored $bla_{VIM-2}$. The $bla_{IMP-6}$ gene was in a class 1 integron containing five gene cassettes: $bla_{IMP-6}$, qac, aacA4, $bla_{OXA-1}$, and aadA1. Some strains that produce IMP-6 and VIM-2 showed epidemiological relationships. The $bla_{IMP-6}$ gene in carbapenem-resistant P. aeruginosa showed an identical pattern to a gene cassette that was reported at a hospital in Daegu, Korea. Therefore, MBL-producing P. aeruginosa is already endemic in the community. We are concerned that the existence of carbapenem-resistant bacteria containing the blaMBL gene may increase pressure on antibiotic selection when treating infections. We believe that we should select appropriate antibiotics based on the antibiotic susceptibility test and continue the research to prohibit the emergence and spread of antibiotics resistant bacteria.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.20-27
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• 1994

An inducible ${\beta}$-lactamase gene (bla) was identified and isolated from the chromosomal DNA of multiple drug resistant strains of Staphylococcus aureus. Determined base sequence of bla and of its flanking region was compared with those of bla genes identified on the staphylococcal plasmids pPC1, pI258, pI1071, and pUB101. Base sequence of 843 base-long structural gene of our bla was same as that of pPCl-, pI258-, and pS1-bla. However, HindIII recognition site Which is found in most of the bla genes at 140 base upstream from the structural gene was moved to the site of 370 base upstream from the structural gene. And one of the two direct repeat sequence found in downstream flanking region of pI1071-bla was deleted in our bla. Amino acid sequence homology analysis of the ORF located around HindIII recognition site reveals that this 80 amino acids-long polypeptide is C-terminus of transposase of Tn4001.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.303-307
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• 2010

Acinetobacter baumannii 1625, a clinical isolate identified by Vitek and 16S rDNA sequence, showed an extended resistance to most ${\beta}$-lactams including imipenem, kanamycin, gentamicin, tobramycin, and cephalosporins of the third and fourth generations, and produced metallo-${\beta}$-lactamase (MBL) of IMP-1 type which is rare in Korea. The isolate contained a class 1 integron of about 2.5 kb in size and the integron included accA4 (aminoglycoside resistance gene), $bla_{IMP-1}$ (carbapenem resistance gene), and $bla_{OXA-2}$ (extended-spectrum ${\beta}$-lactam resistance gene) gene cassettes in order. The coexistence of IMP-1 type and OXA-2 type ${\beta}$-lactamase gene cassettes in an integron has not been reported in Korea. The transformed integron rendered the E. coli transformant resistant more than eight folds against imipenem, ampicilin, piperacillin, cefazolin, cefoperazone, and aztreonam comparing to the reference strain. This study clearly showed that the extended multi-drug resistance of A. baumannii 1625 was mainly due to the integron.