• Clinical and Experimental Pediatrics
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• v.49 no.7
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• pp.777-783
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• 2006

Purpose : Urinary tract infection(UTI) is one of the most frequent infections in children. E. coli is the most frequent etiological micropathogen in pediatric community UTI, and E. coli has developed resistance to many antibiotics, highlighting the need for regular surveys of this organism resistant patterns in the community. The aim of this study was to determine the oral antibiotic susceptibility patterns of E. coli, isolated from pediatric patients with uncomplicated community acquired UTI. Methods : E. coli isolates, obtained from pediatric patients with uncomplicated community acquired UTI between October in 2004 to September in 2005. And minimal inhibitory concentrations(MICs) of oral aminopenicillins and beta-lactamase inhibnitors(ampicillin, amoxacillin, ampicillin-sulbactam), oral cephalosporins(cefaclor, cefixime) and sulfa drug(trimethoprime-sulfamethoxazole) were performed according to the National Committee for Clinical Laboratory Standards(NCCLS) guide line. Results : Total 211 organisms were isolated from pediatric out-patients with community UTI. E. coli was the most common organism(89 percent), followed by E. fecalis, Proteus species, S. aureus, M. morganii, and P. aeruginosa. The resistant rates of aminopenicillins and beta-lactamase inhibitors, cefaclor and sulfa drug to E. coli were very high. But, the resistant rate of cefixime was markedly low, and ESBL strains were isolated with small rates. Conclusion : Our study results suggest that aminopenicillins, cefaclor and sulfa drug may not be useful as first line empirical antibiotics to treat pediatric patients with community UTI in Korea. But, 3rd generation cephalosporin such as cefixime can be used as effective second line antibiotics after primary treatment failure, also may be useful as an empirical first line antibiotic. Finally, we conclude that a continuous surveillance study to monitor susceptibility patterns of E. coli in community UTI will be needed for the standard guide lines of empirical oral antibiotic treatment.

• Toxicological Research
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• v.21 no.1
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• pp.39-43
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• 2005

The present study was carried out to investigate the antibacterial activity against Staphylococcus aureus with antibiotic-resistance in vitro and the skin irritation in rabbits with surfactin produced by Bacillus subtilus Complex BC1212. The antibacterial activities of selected antimicrobial agents (surfactin, amoxacillin, colistin, norfloxacin and streptomycin) were evaluated by using the broth microdilution method. As the results, the minimum inhibitory concentration (MIC) of the surfactin was less than 15.6 ㎍/ml. In the skin irritation test, two out of 4 rabbits showed very slight edema at 24 h after the administration of surfactin, and then recovered at 72 h. The change of body weight was normal during the skin irritation test. The primary irritation index in accordance with the Draize evaluation of topical reaction was calculated to be '0.125', which meant not irritating. Based on these results, it could be concluded that the test agent, surfactin, was a non-irritant. We could also think that the surfactin may be useful for the treatment of S. aureus infections such as bovine mastitis.

• Korean Journal of Microbiology
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• v.28 no.1
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• pp.47-54
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• 1990

In order to investigate physiological characteristics of fusants by interspecific protoplast fusion of the genus Cellulomonas, protoplasts of Cellulomonas flavigena NCIB 12901 and Cellulomonas bibula NCIB 8142 were fused and cell wall regenerated. To give gene maker, C. bibula was treated with 500 ug/ml NTG for 1 hr and arginine requiring auxotrophic mutants were isolated. Protoplasts of the genus Cellulomonas were obtained by treatment with $600{\mu}{\textrm{g}}$/ml lysozyme, and 0.5M sorbitol was optimal for osmotic stabilizer on protoplast fromation. Protoplast fusion was enhanced by 40% PEG)M.W.6,000) containing 25 mM $CaCl_{2}$ at $30^{\circ}C$ for 30 min and fusion frequency between C. bibula and C. flavigena was $5\times 10^{-4}$. Processes of protoplast formation, cell wall regeneration and protoplast fusion were obsdrved by scanning electron microscope. By comparing enzyme activities of cellulase, exocellobiohydrolase, .betha.-glucosidase of the parent strains of Cellulomonas with those of thier mutants and fusants, fusants with increased enzyme activity were obtained. By the studies on nutritional requirement, antibiotic resistance, cellulolytic enzyme activities, type of peptidoglycan and motility of two mutants and fusants, fusants were proved to be recombinant of both mutant strains.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1604-1608
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• 2000

Penicillin antibiotics such as penicillin G, ampicillin and amoxicillin have been widely used in the pig industry to control salmonellosis, bacterial pneumonia, and urinary tract infections. Extensive use of antibiotics in veterinary clinics has resulted in tissue residues and bacterial resistance. To prevent unwanted drug residues entering the human food chain, extensive control measures have been established by both government authorities and industries. The demands for reliable, simple, sensitive, rapid and low-cost methods for residue analysis of foods are increasing. In this study, we established a rapid prediction test for the detection of pigs with unacceptable tissue residues of penicillins. The recommended therapeutic doses of three penicillins, penillin G (withdrawal time, 7 days), ampicillin (withdrawal time, 7 days) and amoxicillin (withdrawal time, 14 days), were administered to three groups of 20 pigs each. Blood was sampled before drug administration and during the withdrawal period. The concentration of penicillins in plasma, determined by a semi-quantitative ELISA, were compared to that of internal standard, 4 ppb, which corresponded to the Maximum Residue Limit in milk. The absorbance ratio of internal standard to sample (B/Bs) was employed as an index to determine whether drug residues in pig tissues were negative or positive. That is, a B/Bs ratio less than 1 was considered residue positive, and larger than 1 negative. All 60 plasma samples from pigs were negative to three penicillins at pretreatment. Penicillin G could be detected in the plasma of the treated pigs until day 4 post-treatment and ampicillin until day 2, whereas amoxicillin could be detected until day 10 of its withdrawal period. The present study showed that the semi-quantitative ELISA could be easily adapted to detect residues of penicillin antibiotics (penicillin G, ampicillin and amoxicillin) in live pigs.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.283-289
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• 2019

Overuse of antibiotics has significantly contributed to an increase in microbial antibiotic resistance, causing difficulties in the suppression of microbe-borne infectious diseases. In this study, we determined the anti-Klebsiella pneumoniae effect in the kidneys of mice induced by peptides isolated from H. illucens larvae. Mice were intranasally infected with a high dose of K. pneumoniae and 1 day later, peptides were introduced through the intramuscular route. Mice were sacrificed on day 10 upon K. pneumoniae infection to determine the bacterial loads in the kidneys. Mice receiving peptide treatment demonstrated significantly reduced bacterial loads, reduced bodyweight loss, and higher survival in a dose-dependent manner compared to control. These results indicate that peptide isolated from H. illucens larva inhibits K. pneumoniae infection in the kidney. The peptide from H. illucens larva could be a potential candidate for the development of an effective antibacterial drug.

• Korean Journal of Veterinary Service
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• v.38 no.1
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• pp.19-23
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• 2015

This study was carried out to investigate the genital tract bacterial flora of riding mare in Jangsu stud farm during March to September, 2014. The specimens were collected from vaginal and uterus using a swab from 104 riding mares. Colonies were selected on blood and MacConkey agar plates, and identified as standard biochemical properties and Maldi-Tof MS. From this study, we isolated 148 strains including Escherichia (E.) coli (14.19%), Streptococcus (S.) equi subsp. zooepidemicus (2.7%), Streptococcus (S.) dysgalactiae subsp. equisimilis (2.03%), Klebsiella (K.) pneumonia (1.35%) and other strains from riding mares. In antimicrobial agents susceptibility test, it showed a high sensibility to the antibiotics of the most. E. coli and S. zooepidemicus were visible to have a high sensibility to almost antibiotics used in this study. However, K. pnemoniae showed a high antibiotic resistance patterns. These results may provide the basic information to establish strategies for the treatment and prevention of reproductive diseases in riding mares in Korea.

• Journal of Veterinary Clinics
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• v.24 no.1
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• pp.19-25
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• 2007

This study carried out to investigate the genital tract bacterial flora of Thoroughbred mare in Jeju province during March and July, 2006. The specimens were collected from vaginal ucosa and clitorial fossa using a culture swab (BBL, USA) from 100 Thoroughbred mares. Colonies were selected blood and MacConkey agar plate, and identified as standard biochemical properties using Biolog system (Thermo, USA). In this study, 470 gram-negative strains were isolated more frequently than 249 gram-positive strains. We were Isolated Escherichia coli (19.8%), Proteus mirabillis (14.9%), Enterobacter nimipressuralis (7.4%), Enterobacter mobilis (4.7%), Aeromonas encheleia (4.3%), Pseudomonas aeroginosa (3.0%), Staphylococcus aureus (14.9%), Staphylococcus epidermidis (11.2%), Coagulasenegative Staphylococcus spp. (10.0%), Enterococcus faecalis (9.2%), Enterococcus faecium (8.0%), Actinomyces viscosus (7.2%), Micoroccus diversus(6.8%), Streptococcus dysgalactiae subsp. equisimilis(5.2%), Streptococcus equi subsp. zooepidemicus (3.2%), Other non-beta hemolytic Streptococcus spp. (2.0%) and many others from vaginal mucosa and clitorial fossa in Thoroughbred mares. No significant bacteria (Taylorella equigenitalis and Klebsiella pneumonia) were isolated from the mare genital tract. In antimicrobial agents susceptibility test, it shows a high sensibility in the antibiotics of the most which excepts the streptomycin and neomycinm, kanamycin, spectinomycin, compound sulfonamides. Especially, Staphylococcus epidermidis, Enterococcus spp. and Streptococcus spp. were visible a high sensibility in the all antibiotics. However, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus spp. and E. coli were showed a high antibiotic resistance patterns. These results may provide the basic information to establish strategies for the treatment and prevention of reproductive disease in Thoroughbred mares in Korea.

• Clinical and Experimental Pediatrics
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• v.57 no.4
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• pp.186-192
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• 2014

Purpose: The prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) has increased worldwide. The aim of this study was to estimate the proportion of MRMP in a tertiary hospital in Korea, and to find potential laboratory markers that could be used to predict the efficacy of macrolides in children with MRMP pneumonia. Methods: A total of 95 patients with M. pneumoniae pneumonia were enrolled in this study. Detection of MRMP was based on the results of specific point mutations in domain V of the 23S rRNA gene. The medical records of these patients were reviewed retrospectively and the clinical course and laboratory data were compared. Results: The proportion of patients with MRMP was 51.6% and all MRMP isolates had the A2063G point mutation. The MRMP group had longer hospital stay and febrile period after initiation of macrolides. The levels of serum C-reactive protein (CRP) and interleukin-18 in nasopharyngeal aspirate were significantly higher in patients who did not respond to macrolide treatment. CRP was the only significant factor in predicting the efficacy of macrolides in patients with MRMP pneumonia. The area under the curve for CRP was 0.69 in receiver operating characteristic curve analysis, indicating reasonable discriminative power, and the optimal cutoff value was 40.7 mg/L. Conclusion: The proportion of patients with MRMP was high, suggesting that the prevalence of MRMP is rising rapidly in Korea. Serum CRP could be a useful marker for predicting the efficacy of macrolides and helping clinicians make better clinical decisions in children with MRMP pneumonia.

• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1200-1209
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• 2021

Sepsis is an acute inflammatory response that leads to life-threatening complications if not quickly and adequately treated. Cytolysin, hemolysin, and pneumolysin are toxins produced by gram-positive bacteria and are responsible for resistance to antimicrobial drugs, cause virulence and lead to sepsis. This work assessed the effects of aloe-emodin (AE) and photodynamic therapy (PDT) on sepsis-associated gram-positive bacterial toxins. Standard and antibiotic-resistant Enterococcus faecalis, Staphylococcus aureus, and Streptococcus pneumonia bacterial strains were cultured in the dark with varying AE concentrations and later irradiated with 72 J/cm^-2 light. Colony and biofilm formation was determined. CCK-8, Griess reagent reaction, and ELISA assays were done on bacteria-infected RAW264.7 cells to determine the cell viability, NO, and IL-1β and IL-6 pro-inflammatory cytokines responses, respectively. Hemolysis and western blot assays were done to determine the effect of treatment on hemolysis activity and sepsis-associated toxins expressions. AE-mediated PDT reduced bacterial survival in a dose-dependent manner with 32 ㎍/ml of AE almost eliminating their survival. Cell proliferation, NO, IL-1β, and IL-6 cytokines production were also significantly downregulated. Further, the hemolytic activities and expressions of cytolysin, hemolysin, and pneumolysin were significantly reduced following AE-mediated PDT. In conclusion, combined use of AE and light (435 ± 10 nm) inactivates MRSA, S. aureus (ATCC 29213), S. pneumoniae (ATCC 49619), MDR-S. pneumoniae, E. faecalis (ATCC 29212), and VRE (ATCC 51299) in an AE-dose dependent manner. AE and light are also effective in reducing biofilm formations, suppressing pro-inflammatory cytokines, hemolytic activities, and inhibiting the expressions of toxins that cause sepsis.

• Korean Journal of Microbiology
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• v.55 no.2
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• pp.87-102
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• 2019

Most chronic wounds persist in the inflammatory phase during wound healing due to the biofilm. Biofilms are resistant to antibiotics, weakening penetration, resistance to biocides and weakening local immune responses. The biofilm is firmly attached to the surrounding tissues and is very difficult to remove. Therefore, strategies to remove hard biofilms without damaging surrounding tissue are very important. One of possible strategies is dispersal. So many studies have been done to develop new strategies using dispersal mechanisms. In this review paper, especially chemotaxis, phage therapy, polysaccharides, various enzymes (glycosidases, proteases, and deoxyribonucleases), surfactants, dispersion signals, autoinducers, inhibitors were introduced. Combination therapies with other therapies such as antibiotic therapy were also introduced. It is expected that the possibility of treatment of chronic wound infection using the knowledge of the biofilm dispersal mechanisms presented in this paper will be higher.