• Journal of Veterinary Clinics
• /
• v.38 no.5
• /
• pp.225-230
• /
• 2021

A 4-year-old gelding Thoroughbred racehorse, which had been undergoing antibiotic therapy at a local veterinary clinic, was referred to the KRA veterinary center with a 20-day history of continuous right nasal discharge. Patient's history, endoscopic examination, and radiographic examination revealed primary maxillary sinusitis. Under sedation, surgical intervention was performed to collect samples and remove the accumulated mucopurulent exudate in the sinus. Swab samples were collected from the sinus during surgery for cytology and antimicrobial susceptibility testing. Only one type of bacteria was cultured, and molecular analyses of 16S ribosomal RNA gene sequences identified it as Staphylococcus aureus (S. aureus). The isolate was resistant to multiple antibiotics, which are frequently used in equine practice. Trimethoprim-sulfamethoxazole was chosen based on antibiotic susceptibility test, trephination, and sinus lavage using saline were applied to treat bacterial sinusitis. The clinical signs improved after 1 month and the patient resumed training. This report describes S. aureus isolated from bacterial maxillary sinusitis in a horse and its antibiotic susceptibility.

• Korean Journal of Veterinary Service
• /
• v.41 no.4
• /
• pp.229-237
• /
• 2018

Identification of antibiotic resistant bacteria isolated from animals is necessary for seeking a proper treatment and for preventing the spread of the bacteria among animals. Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is of worldwide concern in veterinary medicine. This study was conducted to investigate the antimicrobial susceptibility of Staphylococcus pseudintermedius (S. pseudintermedius) isolated from dogs and cats. Out of the total number of 150 specimens, 35 isolates (23.3％) were identified as S. pseudintermedius when tested by MALDI-TOF MS (Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectroscopy). Among them, 5 isolates (14.3%) were the case of MRSP. In the results of the antimicrobial susceptibility test, the isolates of S. pseudintermedius were susceptible to amikacin (100%), cephalothin (100%), vancomycin (100%), amoxicillin (85.7%), oxacillin (85.7%), enrofloxacin (82.8%), chloramphenicol (80%). On the other hand, they were resistant to penicillin (71.4%), tetracycline (48.6%), ampicillin (37.1%), kanamycin (31.5%), erythromycin (31.4%), respectively.

• Microbiology and Biotechnology Letters
• /
• v.29 no.1
• /
• pp.1-11
• /
• 2001

Lactic acid bacteria (LAB) are widely used for various food fermentation. With the recent advances in modern biotechnology, a variety of bio-products with the high economic values have been produced using microorganisms. For molecular cloning and expression studies on the gene of interest, E. coli has been widely used mainly because vector systems are fully developed. Most plasmid vectors currently used for E, coli carry antibiotic-resistant markers. As it is generally believed that the antibiotic resistance markers are potentially transferred to other bacteria, application of the plasmid vectors carrying antibiotic resistance genes as selection markers should be avoided, especially for human consump-tion. By contrast, as LAB have some desirable traits such that the they are GRAS(generally recognized as safe), able to secrete gene products out of cell, and their low protease activities, they are regarded as an ideal organism for the genetic manipulation, including cloning and expression of homologous and heterologous genes. However, the vec-tor systems established for LAB are stil insufficient to over-produce gene products, stably, limiting the use of these organisms for industrial applications. For a past decade, the two popular plasmid vectors, pAM$\beta$1 of Streptococcus faecalis and pGK12 theB. subtilis-E. coli shuttle vector derived from pWV01 of Lactococcus lactis ssp. cremoris wg 2, were most widely used to construct efficient chimeric vectors to be stably maintained in many industrial strains of LAB. Currently, non-antibiotic markers such as nisin resistance($Nis^{r}$ ) are explored for selecting recombi-nant clone. In addition, a gene encoding S-layer protein, slp/A, on bacterial cell wall was successfully recombined with the proper LAB vectors LAB vectors for excretion of the heterologous gene product from LAB Many food-grade host vec-tor systems were successfully developed, which allowed stable integration of multiple plasmid copies in the vec-mosome of LAB. More recently, an integration vector system based on the site-specific integration apparatus of temperate lactococcal bacteriophage, containing the integrase gene(int) and phage attachment site(attP), was pub-lished. In conclusion, when various vector system, which are maintain stably and expressed strongly in LAB, are developed, lost of such food products as enzymes, pharmaceuticals, bioactive food ingredients for human consump-tion would be produced at a full scale in LAB.

• Journal of Life Science
• /
• v.28 no.12
• /
• pp.1529-1535
• /
• 2018

The number of antibiotic-resistant bacteria is increasing rapidly while the discovery rate of new antibiotics is in decline. A systematic study is therefore necessary to investigate which bacteria are resistant to medically important antibiotics and how high that resistance is. To that end, this study aimed to analyze which bacteria demonstrated resistance to ampicillin, one of the currently most-widely used medical antibiotics. Water samples were collected from the Changwon-Cheon that runs through Changwon City and from the pond in front of the dormitory building at Changwon University. Hundreds of ampicillin-resistant colonies were obtained and 22 morphologically distinct examples were chosen for further study. These bacteria were identified by amplifying their 16S rRNA genes and comparing those sequences with data in GenBank. The bacteria was identified as belonging to 10 families, 12 genera, and 17 species, and all were able to grow in the presence of $50{\mu}g/ml$ ampicillin while seven showed growth at ampicillin concentrations as high as 1.5 mg/ml.

• Korean Journal of Veterinary Research
• /
• v.47 no.1
• /
• pp.67-75
• /
• 2007

Environmental mastitis has increased particularly in well-managed or low somatic cell countherds that have successfully controled contagious pathogens. Major pathogens of environmental mastitisare Escherichia coli (E. coli) and Streptococcus uberis. The present study was conducted to investigate1,865 quaters of 241 Korean dairy farms from 2001 to 2004. Prevalence of major gram-negative bacteriaisolated from mastitis milk were E. coli (22.7%) and Enterobacter spp. (16.3%) in coliforms and Pseudomoassp. (10.3%) and Serratia spp. (7.9%) in non-coliforms. The results on antibiotic susceptibility by agardifusion test against these pathogens were 86.7% in piperaciliin, 94.6% in cefepime, 85.5% in amikacin,87.7% in gentamicin and so on. In contrast, the susceptibility against ampicillin (41.9%), cephalothin (9.9%),streptomycin (39.9%) and tetracycline (46.7%) appeared to be below 50%. Gram-negative bacteria showed(96.8%). Acording to year, distribution of high $256{\sim}64{\mu}g/ml$ on cephalothin get increased, but the othersare diferent. These findings demonstrate that major gram-negative bacteria were E. coli and Enterobacterspp. isolates, and often encountered the diverse antibiotic resistant patterns.

• Korean Journal of Microbiology
• /
• v.40 no.1
• /
• pp.1-6
• /
• 2004

Tetracycline resistant bacterial strains were isolated from 10 batches of Kimchi among 50 batches collected in Taegu restrict. The MIC of tetracycline ranged between 25 and> 100 ㎖/l. Total genomic DNA preparation from all 10 tetracycline resistant lactic acid bacterial isolates were subjected to PCR amplification with class-specific primers for tet(M) and tet(O). In only one isolate, HJ9, tet(M) was detected. By Southern blotting and hybridization with a tet(M)-specific probe, the tet(M) gene of HJ9 isolate could be localized on a plasmid. The partial nucleotide sequence and deduced amino acid sequence of tet(M) of HJ9 showed 90-99% and 94-100% homology to those of Gram positive bacteria, respectively. With sequencing of 16S rRNA, HJ9 isolate from Kimchi was identified as Lactobacillus sakei. From these results, Kimchi can be considered potential vehicle for the spread of antibiotic-resistant lactic acid bacteria along the food chain to the consumer.

• Korean Journal of Environmental Agriculture
• /
• v.29 no.4
• /
• pp.315-327
• /
• 2010

A vast increase of antibiotics usage in concentrated animal feeding operations (CAFOs) over the last few decades has led to an environmental risk due to the presence of antibiotic residuals in different environmental compartments. Especially in Korea, the use of antibiotics in CAFOs is much greater than in other developed countries. One of the primary adverse impacts of antibiotic residuals in the environment is that they readily produce antibiotic resistant bacteria (ARB), which exert detrimental effects on the ecosystem as well as human health. In this article, the impacts of veterinary antibiotic residuals with regard to their quantification and management, and desirable remediation technologies have been widely reviewed. This review article concluded that the continuous monitoring should be required to ensure the safety of antibiotic residuals in the surrounding environments. Furthermore, the management guidelines of antibiotic residuals need to be developed in the future.

• The Korean Journal of Mycology
• /
• v.34 no.2
• /
• pp.92-97
• /
• 2006

The liquid culture extract of Coriolus versicolor was prepared by directly boiling the whole culture broth 7 days after incubation in 12% citrus extract medium. After removal of mycelial debris through filtration, this extract was further extracted with equal volume of ethyl acetate (1 : 1, v/v). The ethyl acetate extracts showed significant antibacterial activities against Stapylococcus aureus CCARM3230 and Psudomonas aeruginosa CCARM2171, which are resistant to several antibiotics. The most active fraction was eluted from a silica gel column with a mixture of dichloromethane and methanol (9 : 1, v/v) and the purity of this active substance was confirmed by HPLC analysis. The results suggest that the purified active substance could be a good source for the development of a new antimicrobial agent, especially for the treatment of antibiotic resistant bacteria.

• The Journal of the Korean Society for Microbiology
• /
• v.9 no.1
• /
• pp.19-24
• /
• 1974

During March to October 1973 at National Medical Center, one thousand four hundred sixty four pathogens that exclude penicillin sensitive organisms such as gonococcus, pneumococcus, streptococcus; ampicillin sensitive H. influenzae and gentamicin sensitive pseudomonas spp, were isolated. These strains identified as follows: Sta. aureus 399 E. coli 359 Sta. epidermidis 183 Klebsiella spp 171 Proteus spp 103 B. anitratum 80 Salmonella spp 68 Enterococcus 53 Shigella spp 48 In general, Sta. epidermidis is regarded as nonpathogen, however, author included pure culture of this bacteria in this study. 1. High susceptibility to staphylococcus reveals cephalosporin, methicillin, gentamicin & leucomycin. 2. Ampicillin is only one susceptible antibiotic to Enterococcus. 3. Cephalosporin and gentamicin reveal susceptible antibiotics to E. coli. 4. Gentamicin is only one susceptible antibiotic to Klebsiella spp. 5. Gentamicin & carbenicillin reveal moderately susceptible antibiotics to Proteus spp. 6. There is no susceptible antibiotic to B. anitratum. 7. About thirty percent strains of salmonella are resistant to chloramphenicol. 8. Carbenicillin, cephalosporin & gentamicin reveal susceptible to shigella spp. 9. Multiple resistant rate to more than two antibiotics which includes tetracycline are as follows. Sta. aureus 56.5% E. coli. 80.9% Shigella spp 93.8%

• Journal of the Korean Wood Science and Technology
• /
• v.52 no.2
• /
• pp.145-156
• /
• 2024

Unlike resistant cells, persister cells resist antibiotics due to a decreased cellular metabolic rate and can transition back to normal susceptible cells when the antibiotic is removed. These persister cells contribute to the chronic symptoms of infectious diseases and promote the emergence of resistant strains with continuous antibiotic exposure. Therefore, eliminating persister cells represents a promising approach to significantly enhance antibiotic efficacy. Here, we found that Coicis Semen extract reduced Staphylococcus aureus persister cells at a concentration of 0.5 g/L. Linoleic acid and oleic acid, the major components of Coicis Semen extract, exhibited a comparable reduction in persister cells when combined with three antibiotics: ciprofloxacin, oxacillin, and tobramycin. Conversely, these effects were nullified in the presence of the surfactant Tween 80 (1%), suggesting that the hydrophobic characteristics of linoleic acid and oleic acids play a pivotal role in reducing the number of S. aureus persister cells. Considering the concentration-dependent effects of linoleic acid and oleic acid, the persister-reducing activity of Coicis Semen extract was primarily attributed to these fatty acids. Moreover, Coicis Semen extract, linoleic acid, and oleic acid increased the cell membrane permeability of S. aureus. Interestingly, this effect was counteracted by 1% Tween 80, indicating a close association between the reduction of persister cells and the increase in cell membrane permeability. The identified compounds could thus be used to eliminate persister cells, thereby enhancing therapeutic efficacy and shortening treatment duration. When used in conjunction with antibiotics, they may also mitigate chronic symptoms and significantly reduce the emergence of antibiotic-resistant bacteria.