• Journal of Microbiology and Biotechnology
• /
• v.16 no.1
• /
• pp.109-117
• /
• 2006

The Rev binding to Rev Responsive Element (RRE) of HIV-1 mRNA plays an important role in the HIV-I viral replication cycle. The disruption of the Rev-RRE interaction has been studied extensively in order to develop a potential antiviral drug. In order to provide the basis for a more promising approach to develop a Rev-RRE binding inhibitor against HIV-I infection, it is necessary to understand the binding modes of the aminoglycoside antibiotics to RRE. In the present study, the binding mode of a modified antibiotic, a neamine conjugated with pyrene and arginine (NCPA), to RRE has been studied by the methods of $T_m$ measurement and spectroscopic analysis of RRE with or without antibiotics. The results confirmed that NCPA competes with Rev in binding to RRE.

• Korean Journal of Clinical Laboratory Science
• /
• v.36 no.2
• /
• pp.76-88
• /
• 2004

The purpose of this study was to investigate the distribution of Enterococci isolated from clinical specimens, and identify the aspect of antibiotic susceptibility and analyze the genetic difference by executing Rep-PCR over the strains resistant to aminoglycoside-typed antibiotics. From an assortment of the clinical specimens, 100 strains were isolated. The collection consisted of 49 strains of E. faecalis, 34 strains of E. faecium, 9 strains of E. avium, 4 strains of E. gallinarum, 3 strains of E. casseliflavus, and 1 strain of E. hirae. Ninety five were isolated from inpatients, and five strains were isolated from outpatient. Most of the E. faecalis and E. faecium were originated from urine, pus, and sputum. Most Enterococci showed 80% resistance to the cephalosprin-typed antibiotics. E. faecium showed the high resistance to all the antibiotic substances. One tenths of Enterococci showed the resistance to vancomycin. And also, most Enterococci showed the high resistance to amikacin and gentamicin as aminoglycoside-typed antibiotics. Genetic diversity of the resistant strains to aminoglycoside estimated using Rep-PCR was not significanty different.

• Journal of Microbiology and Biotechnology
• /
• v.8 no.2
• /
• pp.146-151
• /
• 1998

The aminoglycoside multiple-resistance determinant from Streptoalloteichus hindustanus was cloned into Streptomyces lividans and named nbrB. The 1.2-kb ApaI- BclI fragment encompassing nbrB was located within a 2.6-kb ApaI fragment by successive subcloning experiments. The complete DNA nucleotide sequence of 1.2-kb containing nbrB was determined. The sequence contains an open reading frame that putatively encodes a polypeptide of 281 amino acids with a predicted molecular weight of 30,992. The deduced amino acid sequence of nbrB shows identities of 85.1% to kgmB of S. tenebrarius, 59.6% to sgm of Micromonospora zionensis, and 57.7% to grm of M. rosea. The similarity of nbrB to kgmB suggests that nbrB encodes a 16S rRNA methylase similar to that encoded by kgmB and that both genes might be derived from a common ancestral gene.

• Food Science and Biotechnology
• /
• v.15 no.4
• /
• pp.511-515
• /
• 2006

Antibiotic resistance of foodborne pathogens adapted to garlic (Allium sativum Linn.) was determined in order to understand the relationship between antibiotic resistance and garlic. The Gram (-) strains of Escherichia coli and Salmonella typhimurium and the Gram (+) strains of Bacillus cereus and Staphylococcus aureus were subcultured consecutively in a garlic broth, and the surviving colonies on the agar were selected as the adapted strains. Minimal inhibitory concentrations (MIC) for 15 antibiotics on the adapted strains were determined on Muller-Hinton Infusion agar. Adaptation to 1.3%(v/v) garlic juice increased MIC for vancomycin, aminoglycoside, and erythromycin on B. cereus, and for ampicillin and erythromycin on E. coli O157:H7. MIC of aminoglycosides, chloramphenicol, and vancomycin on the adapted S. aureus increased. The adapted S. typhimurium was more resistant to penicillin and vancomycin than the non-treated strain. The adapted S. typhimurium and S. aureus lost their antibiotic resistance in non-garlic stress conditions. However, the adapted B. cereus was still resistant to erythromycin and vancomycin, and the adapted E. coli was also resistant to erythromycin. Antibacterial garlic might increase the antibiotic resistance of E. coli, B. cereus, S. aureus, and S. typhimurium and this resistance can continue even without the stress of garlic. Therefore, garlic as a food seasoning could influence the resistance of such pathogens to these antibiotics temporarily or permanently.

• Korean Journal of Clinical Laboratory Science
• /
• v.38 no.3
• /
• pp.166-172
• /
• 2006

Metallo-${\beta}$-lactamase (MBL) can hydrolyze all ${\beta}$-lactams except monobactams and frequently coexists with various antibiotic resistance genes such as aminoglycoside resistance, sulfonamide resistance gene, etc. Therefore, the effective antibiotics against infections by these bacteria are markedly limited or can't even be found. We tried to search in-vitro antimicrobial combinations with synergistic effects for a VIM-2 type MBL producing Pseudomonas aeruginosa, isolated from clinical specimen. On the selection of antibiotic combinations with synergistic effects, we performed a one disk synergy test, modified Pestel's method, in agar without aztreonam (AZT). The bacteriostatic synergistic effects of this tests were scored as $S_1$ (by susceptibility pattern in agar without antibiotics), $S_2$ (by the change of susceptibility in agar with or without antibiotics) and $S_3$ ($S_1$ + $S_2$) and was classified into weak (1 point), moderate (2 points) and strong (3 points) by $S_3$ score. Subsequently, we carried out the time-killing curve for the antibiotic combinations with the strong synergistic bacteriostatic effect. One VIM-2 type MBL producing P. aeruginosa confirmed by the PCR showed all resistance against all ${\beta}$-lactams except AZT, aminoglycoside and ciprofloxacin. In the one disk synergy test, this isolate showed a strong bacteriostatic synergistic effect for the antibiotic combination of AZT and piperacillin-tazobactam (PIP-TZP) or AZT and amikacin (AN). On the time-killing curve after six hours of incubation, the colony forming units (CFUs/mL) of this bacteria in the medium broth with both combination antibiotics were decreased to 1/18.7, 1/17.1 of the least CFUs of each single antibiotics. The triple antibiotic combination therapy including AZT, PIP-TZP and AN was shown to be significantly synergistic after 8 hrs of exposure. In a VIM-2 MBL producing P. aeruginosa with susceptibility for AZT, the triple antibiotic combination therapy including AZT, PIP-TZP and AN may be considered as an alternative antibiotics modality against the infection by some MBL type. But the antimicrobial combination therapy for many more MBL producing isolates is essential to know as soon as possible for the selection of effective treatment against the infection by this bacteria.

• Fisheries and Aquatic Sciences
• /
• v.19 no.10
• /
• pp.45.1-45.5
• /
• 2016

As a novel strategy to remove ${\beta}$-lactam antibiotic residues from fish tissues, utilization of ${\beta}$-lactamase, enzyme that normally degrades ${\beta}$-lactam structure-containing drugs, was explored. The enzyme (TEM-52) selectively degraded ${\beta}$-lactam antibiotics but was completely inactive against tetracycline-, quinolone-, macrolide-, or aminoglycoside-structured antibacterials. After simultaneous administration of the enzyme with cefazolin (a ${\beta}$-lactam antibiotic) to the carp, significantly lowered tissue cefazolin levels were observed. It was confirmed that the enzyme successfully reached the general circulation after intraperitoneal administration, as the carp serum obtained after enzyme injection could also degrade cefazolin ex vivo. These results suggest that antibiotics-degrading enzymes can be good candidates for antibiotic residue depuration.

• The Korean Journal of Physiology
• /
• v.23 no.1
• /
• pp.23-34
• /
• 1989

Gentamicin (GM) is a polybasic, aminoglycoside antibiotic used frequently for the treatment of serious gram-negative infections. The major limiting factors in the clinical use of GM as well as other aminoglycoside antibiotics are their nephrotoxicity and ototoxicity. The primary mechanism of cell injury in aminoglycoside toxicity appears to be the disruption of normal membrane function and the inhibition of $Na^{+}-K^{+}$ ATPase activity. There are both indirect and direct evidences which suggests that the effect of aminoglycoside antibiotics on $Na^{+}-K^{+}$ ATPase may explain, or contribute to, their toxicity. It has been shown that aminoglycoside reduce total ATPase activity (Kaku et al., 1973) and $Na^{+}-K^{+}$ ATPase activity (linuma et al., 1967) in the stria vascularis and spiral ligament of the guinea-pig cochlea. Lipsky and Lietman (1980) reported that aminoglycoside antibitoics inhibited the activity of $Na^{+}-K^{+}$ ATPase in microsomal fractions of the cortex and medulla of the guinea-pig kidney, isolated rat renal tubule and human erythrocyte ghosts. The present invstigation was undertaken to elucidate the mechanism of GM on human erythrocytes by examining its effect on $Na^{+}-K^{+}$ ATPase activity, actives sodium and potassium transport across red blood cell and $^{3}H-ouabain$ binding to red blood cell membranes. The results obtained are summarized as follows: 1) CM inhibited significantly both the activity of total ATPase and $Na^{+}-K^{+}$ ATPase at all concentrations tested. 2) GM inhibited active $^{22}Na$ efflux across red blood cell. When ouabain is present, the rate of $^{22}Na$ efflux was completely inhibited. When both GM and ouabain were added, the inhibitory effect of active $^{22}Na$ efflux was more pronounced. 3) Active $^{86}Rb$ influx was inhibited significantly by GM. In the presence of ouabain, the rate of $^{86}Rb$ influx is markedly inhibited. But $^{86}Rb$ influx is not appreciably altered by the presence of both GM and ouabain. 4) In the presence of GM, $^{3}H-ouabain$ binding to red blood cell membrane increased. From the above results, it may be concluded that the inhibition of active sodium and potassium transport across red blood cell by gentamicin appears to be due to the inhibition of $Na^{+}-K^{+}$ ATPase activity and an increase in ouabain binding to red blood cell membranes.

• Korean Journal of Veterinary Service
• /
• v.35 no.1
• /
• pp.1-8
• /
• 2012

To detect the virulence genes (invA and spvC) and antimicrobial resistance genes, polymerase chain reaction (PCR) was carried out using total 67 strains of S. Schwarzengrund isolated from pigs. As results, invA was detected from all 67 strains of S. Schwarzengrund, however, spvC was not at all. All 12 strains with ampicillin resistance, 15 strains with chloramphenicol resistance, 9 strains with kanamycin resistance, 1 strain with sulfamethoxazole/trimethoprim resistance, and 66 (98.5%) of 67 strains with tetracycline resistance carried TEM (${\beta}$-lactamase $bla_{TEM}$), cmlA (nonenzymatic chloramphenicol resistance), aphA1-Iab (aminoglycoside phosphotransferase), sulII (dihydropteroate synthase), and tetA (class A tetracycline resistance), respectively. All 63 strains with streptomycin resistance carried 3 aminoglycoside resistance genes, including aadA (aminoglycoside adenyltransferase), strA, and strB (streptomycin phosphotransferase). With respect to prevalence of antibiotic resistance genes occurred in S. Schwarzengrund, genes for strB (46.0%); strA and strB (30.2%); aadA, strA, and strB (9.5%); strA (7.9%); aadA and strB (3.2%); and aadA (3.2%) were detected by PCR.

• Korean Journal of Food Science and Technology
• /
• v.38 no.2
• /
• pp.313-316
• /
• 2006

To obtain antibiotic resistant profiles of Bifidobacterium, minimum inhibitory concentrations (MIC) of 14 antibiotics for 93 Bifidobacterium isolates from Korean intestine origin were determined. All strains tested were sensitive to chloramphenicol, rifampicin, and amoxicillin, whereas resistant to aminoglycoside family, nalidixic acid, and vancomycin. Among vancomycin-resistant strains, 34% were resistant at more than $100\;{\mu}g/mL$, and showed variant resistances toward tetracycline, erythromycin, and penicillin. Their resistances against penicillin, cephalothin, and tetracycline were higher than ten years ago. MIC of ten isolates from commercial yoghurt products were very similar to those of strains from Korean intestine origin, and 20% strains showed resistance at higher than $100\;{\mu}g/mL$ vancomycin. These results indicated patterns of antibiotic resistance against Bifidobacterium from Korean intestine origin and commercial yoghurts were very similar,and prevalence of vancomycin resistance for Bifidobacterium was 20%. To develop new probiotic, antibiotic resistance of vancomycin and risks involved should be evaluated.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.24 no.6
• /
• pp.510-517
• /
• 2021

Purpose: Consensus is lacking regarding the optimal antibiotic treatment for pediatric complicated appendicitis. This study determined the optimal first-line antibiotic treatment for pediatric patients with complicated appendicitis based on peritoneal fluid cultures. Methods: This retrospective study examined the cases of pediatric patients who underwent appendectomy for complicated appendicitis at our institution between 2013 and 2019. Peritoneal fluid specimens obtained during appendectomy were cultured for the presence of bacteria. Results: Eighty-six pediatric patients were diagnosed with complicated appendicitis. Of them, bacteria were identified in 54 peritoneal fluid samples. The major identified bacteria were Escherichia coli (n=36 [66.7%]), Bacteroides fragilis (n=28 [51.9%]), α-Streptococcus (n=25 [46.3%]), Pseudomonas aeruginosa (n=10 [18.5%]), Enterococcus avium (n=9 [16.7%]), γ-Streptococcus (n=9 [16.7%]), and Klebsiella oxytoca (n=6 [11.1%]). An antibiotic susceptibility analysis showed E. coli was inhibited by sulbactam/ampicillin in 43.8% of cases versus cefmetazole in 100% of cases. Tazobactam/piperacillin and meropenem inhibited the growth of 96.9-100% of the major identified bacteria. E. coli (100% vs. 84.6%) and P. aeruginosa (100% vs. 80.0%) were more susceptible to amikacin than gentamicin. Conclusion: Tazobactam/piperacillin or meropenem is a reasonable first-line antibiotic treatment for pediatric complicated appendicitis. In the case of aminoglycoside use, amikacin is recommended.