• Korean Journal of Microbiology
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• v.42 no.4
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• pp.252-256
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• 2006

We monitored antibiotic resistance of Escherichia coli isolates from healthy volunteers of community and hospital patients from February to July in 2006. From disc diffusion test on 4915 E. coli isolates from healthy volunteers of the community, the resistance rates were as follows; tetracycline resistant, 46.6%; ampicillin resistant, 41.1%; ticarcillin resistant,37.9%. From disc diffusion test on 120 E. coli isolates from hospital patients, the resistance rates were as follows: ampicillin resistant, 66.9%; ticarcillin resistant, 63.8%; tetracycline resistant, 47.2%. Extended spectrum $\beta$-lactamase producing E. coli were isolated 0.6% and 4.1% from healthy volunteers and hospital patients.

• Korean Journal of Plant Resources
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• v.33 no.6
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• pp.578-585
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• 2020

This study was designed to assess the possibility of using medicinal plant extracts as β-lactamase inhibitors to control antibiotic-resistant Staphylococcus aureus. The susceptibilities of S. aureus ATCC 15564 (SA^WT), ciprofloxacininduced S. aureus ATCC 15564 (SA^CIP), oxacillin-induced S. aureus ATCC 15564 (SA^OXA), and clinically-isolated S. aureus CCARM 3008 (SA^CLI) to ampicillin were determined in the absence and presence of medicinal plant extracts, including Cleyera japonica (CJ), Carpinus laxiflora (CL), Euphorbia helioscopia (EH), Euscaphis japonica (EJ), Oenothera erythrosepala (OE), and Rosa multiflora (RM). The phenotypic change in the clear inhibition zones around ampicillin disc was observed for SA^WT, SA^CIP, and SA^OXA, indicating the production of ampicillinase. Compared to the controls, the MICs of ampicillin against SA^WT, SA^CIP, and SA^OXA were decreased from 4 to 0.5 ㎍/mL in the presence of CL, 16 to 4 ㎍/mL in the presence of RM, and 32 to 2 ㎍/mL in the presence of CL, EH, and RM, respectively. The medicinal plant extracts, OE, EJ, and CL, effectively inhibited the β-lactamase activities of SA^WT (78%), SA^CIP (57%), and SA^OXA (76%) when compared to the control. This results suggest that the medicinal plant extracts can be used as BLIs to control the antibiotic-resistant S. aureus.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.3
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• pp.330-336
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• 2000

A large number of streptococci that do not fit readily into any of the established classification schemes have been relegated to a large heterogeneous group called the Streptococcus viridans, which are members of the normal flora of the mucous membranes of the body, including the oral cavity, the nasopharynx, and genitourinary tract. This group includes S. mitis, S. oralis, S. sanguis, S. salivarius, S. milleri, etc. Surveying on the literature, it has been reported that infective endocarditis, meningitis, rhabdomyolysis, cholangitis, appendicitis caused by Streptococcus viridans, which were the most important pathogen in children with malignant hematologic disease. Various antibiotics has been chosen for treatment or prophylaxis for these infections, but were generally lower antimicrobial susceptibilities because of an abuse of antibiotics and advent of resistant group. Therefore, surveillant culture must be performed to evaluate personal antimicrobial susceptibilities of intraoral microbes for proper antimicrobial choice for dental procedures. This study examined sampling from subgingival plaque of 60 chidren's microbes. The cultured bacterial isolates, Streptococcus viridans were examined 10 antimicrobial drugs with the Kirby-Bauer agar disk diffusion method. The used drugs were Penicillin, Ampicillin, Oxacillin, Cephalothin, Imipenem, Gentamicin, Erythromycin, Vancomycin, Ciprofloxacin, Clindamycin. The results were as follows : 1. Sampling Streptococcus viridans were S. mitis(65%), S. oralis(22%), S. sanguis(5%), S. intermedius(3%), S. salivarius(2%), S acidominimus(2%), Unidentified streptococcus(2%). 2. The antimicrobial susceptibility of total Streptococcus viridans : Oxacillin< Erythromycin< Pencillin=Ciprofloxacin< Cephalothin< Ampicillin< Clindamycin< Gentamicin< Imipenem=Vancomycin. 3. The antimicrobial susceptibility of S. mitis : Oxacillin=Erythromycin< Ciprofloxacin< Cephalothin< Penicillin=Ampicillin< Gentamicin< Clidamycin< Imipenem=Vancomycin. 4. The antimicrobial susceptibility of S. oralis : Oxacillin< Erythromycin< Penicillin=Ciprofloxacin=Clindamycin< Cephalothin=Gentamicin< Ampicillin< Imipenem=Vancomycin. 5. There was no significant difference in the antimicrobial susceptibility among each Streptococcus viridans group.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.275-282
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• 1987

Strains of bacteria resistant to beta-lactam antibiotics have been increasing in number and are becoming troublesome in clinical medicine. The in vitro antibacterial activity of augmentin, a combination drug consisting of two parts amoxycillin to one part clavulanic acid, a potent beta-lactamase inhibitor, and their minimum inhibitory concentrations were determined by an agar dilution technique against ampicillin-resistant clinical isolates in Korea. Of the 226 strains tested, 140 strains(62%) were resistant to ampicillin. Among the 140 ampicillin-resistant strains, all Salmonella spp. Proteus spp. the majority of S. aureus and Shigella spp. were sensitive to augmentin. Ps. aeruginosa remained 100% resistant and there has been a considerable decline in resistant strains in E. coli and K. pneumoniae although a significant percentage of strains showed intermediate sensitivity. The minimum inhibitory concentrations of augmentin were ranged in $8{\mu}g/ml$ to $32{\mu}g/ml$ in most bacteria and all S. aureus were inhibited by $8{\mu}g/ml$. In our microbiological studies we have shown that augmentin is active against ampicillin-resistant strains of Staphylococci and Gram-negative bacteria. In this hospital there would appear to be a significant number of strains of E. coli and K. pneumoniae showing intermediate resistance to augmentin. Most of these strains should be susceptible to augmentin given by mouth or by the intravenous route depending on the concentrations of both amoxycillin and clavulanic acid obtainable in the various tissues.

• Analytical Science and Technology
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• v.32 no.4
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• pp.147-154
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• 2019

Ampicillin and Sulbactam (2:1, w/w) are combined in formulation to provide broader antibacterial action in treatment of many infections. The development of analytical method for simultaneouly determine these two compounds was difficult because of the differences in their chemical structures and ratio in the formulation. Current published methods still have some limitations. In this study, we developed an alternative high-performance liquid chromatography (HPLC) assay method for simultaneously determination of ampicillin sodium and sulbactam sodium in powder for injection. Method validation of HPLC method was conducted to determine linearity, precision, accuracy, system suitability, robustness. The linearity of the calibration curves in the desired concentration range was good ($r^2$> 0.9994). RSDs of intra-day and inter-day precision obtained were less than 2.00 %. Accuracy was obtained with the recoveries in range of 98.42 % and 101.36 %. As a result of system suitability, RSD of both retention time and the peak area obtained were not more than 1.0 %. The values of plate number were more than 7000 and symmetric factors obtained were 0.8. As intermediate-precision and robustness of the developed assay, it could be expected to become valuable tools for revising the Korean Pharmacopoeia (KP XI).

• Pediatric Infection and Vaccine
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• v.12 no.2
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• pp.157-165
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• 2005

Purpose : Children occupy a large proportion of burn victims. So we want to aid to pediatric burn care through the understanding of the bacterial distribution in burn wounds and antibiotic susceptibility against isolated microorganisms from burn wounds. Methods : We analysed the medical records of 213 pediatric burn patients(0~15 years), 406 samples that grew bacteria in burn wound sites. Results : Of the total 213 patients, male were 59.6% and female were 40.4%. Scalding burn was the most common(78.4%), flame burn was the second(16.4%). Pathogens were isolated in 406 samples. The most common was Pseudomonas aeruginosa(58.1%). Next were Enterococcus species, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus species, Acinetobacter species. P. aeruginosa was resistant to trimethoprim-sulfamethoxazole in 100%, cephalothin in 98.1%, ampicillin-sulbactam in 96.2%, ampicillin in 95.3%, ceftriaxone in 95.2%, tobramycin in 93.7%, cefoperazone in 68.9%, ceftazidime in 67.7%. Enterococcus species were resistant to tetracycline in 63.9%, streptomycin in 45.5%, gentamicin in 36.1%, penicillin G in 13.7%. S. aureus was resistant to gentamicin in 89.7%, tetracycline in 86.2%, ciprofloxacin in 86.2%, penicillin G in 84.3%, oxacillin in 78.4%, erythromycin in 76.5%. Acinetobacter species were resistant to ampicillin-sulbactam in 100%, gentamicin in 85.7%, ampicillin in 83.3%, piperacillin in 61.5%. Conclusion : P. aeruginosa was highly resistant to drugs like cefoperazone in 68.9%, ceftazidime 67.7%. S. aureus was highly resistant to penicillin G in 84.3%, oxacillin in 25.9 %, but none to vancomycin in 0%, teicoplanin in 2.2%. According to the study, Acinetobacter species turned out to be multi-resistant strains, so careful attention must be paid to the choice of antibiotics.

• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1147-1152
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• 2009

Purpose:To characterize the pathogens and their antibiotic susceptibilities in more than 24-month-old children with urinary tract infection (UTI) and to study the Escherichia coli antimicrobial susceptibility trend. Methods:We retrospectively reviewed the record of more than 24-month-old children with UTI between January 2003 and December 2008. Positive results for 1 bacterial species with a colony count of ${\geq}10^5CFU/mL$ was considered statistically significant. We analyzed uropathogens and their antibiotic susceptibilities. To investigate E. coli antibiotic susceptibility trend, we compared 2 study periods (group A: 2003-2005 versus group B: 2006-2008) using the chi-square test for trend. Results:In all, 63 bacterial isolates were identified in children with febrile UTI. The most common pathogen was E. coli (77.8%). There was no difference in the resistance patterns of uropathogens during the 2 study periods (P>0.05). Antibiotic susceptibility of the E. coli isolates to aztreonam, cefotetan, cefotaxime, ceftriaxone, cefepime, amikacin, and imipenem was >90% to trimethoprim/sulfamethoxazol, 49% and to ampicillin and ampicillin/sulbactam, 20-25%. Over the 2 study period, the E. coli susceptibilities to most antibiotics did not change: the susceptibility to cefuroxime increased from 74.1% to 95.5% (P=0.046) and that to ciprofloxacin increased from 59.3% to 86.4% (P=0.039). Conclusion:Empirical treatment with trimethoprim/sulfamethoxazole, ampicillin, and ampicillin/sulbactam alone appeared to be insufficient in childhood UTI because of the high resistance of E. coli and other gram-negative uropathogens. Antibiotics for empirical therapy should be selected based on the sensitivity and resistance pattern of uropathogens found in a particular region.

• Toxicological Research
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• v.29 no.2
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• pp.107-114
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• 2013

Mass spectrometry (MS) is a very powerful instrument that can be used to analyze a wide range of materials such as proteins, peptides, DNA, drugs, and polymers. The process typically involves either chemical or electron (impact) ionization of the analyte. The resulting charged species or fragment is subsequently identified by the detector. Usually, single mass uses source-induced dissociation (SID), whereas mass/mass uses collision-induced dissociation (CID) to analyze the chemical fragmentations Each technique has its own advantages and disadvantages. While CID is most effective for the analysis of pure substances, multiple-step MS is a powerful technique to get structural data. Analysis of veterinary drugs ampicillin, chloramphenicol, ciprofloxacin, and oxytetracycline serves to highlight the slight differences between SID and CID. For example, minor differences were observed between ciprofloxacin and oxytetracycline via SID or CID. However, distinct fragmentation patterns were observed for ampicllin depending on the analysis method. Both SID and CID showed similar fragmentation spectra but different signal intensities for chloramphenicol. There are several factors that can influence the fragmentation spectra, such as the collision energy, major precursor ion, electrospray mode (positive or negative), and sample homogeneity. Therefore, one must select a fragmentation method on an empirical and case-by-case basis.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.329-332
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• 2001

It has been known that, in enzymatic synthesis of cephalexin, the conversion yield was reduced by high loading of ampicillin acylase. In order to elucidate this phenomena, pH-controlled synthesis of cephalexin was examined using a purified Acetobacter turbidans acylase. When the pH of the reaction mixture was maintained at $6.20{\pm}0.04$, the reduction of the maximal conversion rate was not observed even with high enzyme loading. The kinetic parameters also suggest that pH drop during the enzymatic synthesis of cephalexin was mainly attributed to the rapid hydrolysis of D-${\alpha}$-phenylglycine methyl ester to D-${\alpha}$-phenylglycine, rather than the disappearance of 7-amino-3-deacetoxycephalosporanic acid for cephalexin synthesis. At higher molar ratio of two substrates, [D-${\alpha}$-phenylglycine methyl ester]/[7-amino-3-deacetoxycephalosporanic acid], the conversion rate was also elevated under pH-controlled enzymatic synthesis, which implies that the main reason for the pH drop is due to the production of D-${\alpha}$-phenylglycine methyl easter, the effect of a water-methanol cosolvent system on the ester, the effect of a water-methanol cosolvent system on the conversion profile was also examined. Even the though the conversion rate was increased in 10% methanol solution, a higher than 16% methanol in the reaction mixture caused an inactivation of enzyme.

• The Korean Journal of Food And Nutrition
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• v.13 no.6
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• pp.611-618
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• 2000

For the purpose of the isolation of microorganisms which have the capability of nitrification, we isolated the microorganisms in 6 samples collected from the stream of Kyonggi area. 60 strains were isolated. The selected strain were identified as a Aeromonas hydrophila based on the data obtained from the morphological, biochemical and cultural characteristics defined experiments. Among them Aeromonas hydrophila (AH-1), (AH-3) , (AH-4), (AH-6) showed the highest nitrification capability. All isolates were resistant to amoxillin, ampicillin, cephalothin and ticarcillin. Optimum culture conditions of isolates were 37$^{\circ}C$ and 1${\times}$10$\^$8/ cells/ml for 4 hours in the nitrate medium.