• Journal of Veterinary Science
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• v.23 no.6
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• pp.12.01-12.10
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• 2022

Background: Staphylococcus aureus and Streptococcus agalactiae are the main cause of clinical mastitis in dairy cattle in Argentina, whereas coagulase-negative staphylococci (CNS) and environmental streptococci are the main cause of subclinical mastitis. Bacteria isolated from infected animals show increasing antimicrobial resistance. Objectives: This study aims to determine the antimicrobial resistance of staphylococci and streptococci isolated from milk with mastitis, and to genotypically characterize the methicillin-resistant (MR) staphylococci. Methods: Isolation was performed on blood agar and identification was based on biochemical reactions. Antimicrobial susceptibility was according to the Clinical and Laboratory Standards Institute guidelines. The antimicrobial resistance genes, SCCmec type and spa type were detected by the polymerase chain reaction method. Results: We isolated a total of 185 staphylococci and 28 streptococci from 148 milk samples. Among the staphylococcal isolates, 154 were identified as CNS and 31 as S. aureus. Among the 154 CNS, 24.6% (n = 38) were resistant to penicillin, 14.9% (n = 23) to erythromycin, 17.5% (n = 27) to clindamycin, 6.5% (n = 10) to cefoxitin and oxacillin. Among the S. aureus isolates, 16.1% (n = 5) were resistant to penicillin, 3.2% (n = 1) to cefoxitin and oxacillin (MRSA). Six MR isolates (5 CNS and 1 MRSA) were positive to the mecA gene, and presented the SCCmec IVa. The MRSA strain presented the sequence type 83 and the spa type 002. Among the 28 streptococcal isolates, 14.3% (n = 4) were resistant to penicillin, 10.7% (n = 3) to erythromycin and 14.3% (n = 4) to clindamycin. Conclusions: The present findings of this study indicate a development of antimicrobial resistance in main bacteria isolated from cows with mastitis in Argentina.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.381-389
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• 2023

Vibrio vulnificus, the most fatal waterborne and foodborne pathogens of 50% fatality rate in the world, is common in seawater and occurs particularly in warmer months. In this study, we investigated the toxin genes using reverse transcription-polymerase chain reaction (RT-PCR), antibiotic resistance status using Vitek, and genetic characteristics using pulsed-field gel electrophoresis (PFGE) of different V. vulnificus strains isolated from the Jeju Island seawater, distribution fishery products, and fish tanks. We examined a total of 487 samples and isolated a total of 46 strains (including overlapping strains) of V. vulnificus, 44 strains from seawater and 1 strain each from fishery products and fish tank. We detected toxin gene vvhA in all 46 strains and rtxA, viu in 8 strains (17.4%) and 9 strains (19.6%) strains, respectively. Antibiotic resistance tests indicated 100% resistance to cefoxitin antibiotics. The PFGE analysis of the 46 strains identified a total of 6 types showed 100% homology and the degree of similarity was 81.3-98.0%; however, there were no similarity between the regions and samples. These results indicate that V. vulnificus isolated from the seawater, fishery products, and fish tanks should be continuously monitored as cases of food poisoning caused by V. vulnificus with toxin genes have been reported in Jeju Island.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.1
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• pp.59-65
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• 2024

This study examined the fecal samples of striped field mice (Apodemus agrarius coreae) captured in Jeju Special Self-Governing Province. Fecal samples, including the colon and other intestinal organs, were collected and subjected to aerobic culture to investigate the distribution of intestinal microorganisms. Gram staining of the aerobic cultured bacterial colonies from 36 fecal samples revealed the predominant presence of gram-negative bacilli in all samples. Among the 36 samples, gram-negative bacilli were identified in 36 strains (100%), gram-positive cocci in 21 strains (58.3%), and gram-positive bacilli in 15 strains (41.7%), while no gram-negative cocci were observed. The gram-negative bacilli cultured from the 36 samples were identified using the Vitek 2 system, and all were determined to be Escherichia coli (E. coli) strains. In addition, one sample was concurrently identified with E. coli and Enterobacter cloacae strains. The antimicrobial susceptibility testing for the identified E. coli strains did not include all antibiotics, but one strain exhibited intermediate resistance to cefoxitin. No pathogenic bacteria were present in the fecal samples of the scrub typhus-infected rodents, which are vectors for chigger-borne diseases affecting humans and animals.

• Journal of environmental and Sanitary engineering
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• v.22 no.4
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• pp.55-63
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• 2007

We investigated the distribution and drug susceptibility test of V. vulnificus isolated from environmental sources in Incheon. In this survey, total 4,302 samples were obtained from different sites of the Incheon coastal area during the periods from march 2004 to November 2006. Among the 4,302 samples, 310 strains were isolated. The isolation rates of Vibrio vulnificus from fish, shellfish, estuarine water and sediment were 6.7%, 4.7%, 12.4% and 23.2%, respectively. The highest isolation rate was 14.6% in September and in spite of low temperature the isolation rate was 5.1% in November. The highest rate of antibiotic resistance was observed against streptomycin(15.3%), cefazolin(8.5%), cephalothin(8.3%), amikacin(8.3%), cefoxitin(6.7%) and nalidixic acid(6.7%). Seventeen percent of isolates were observed to be resistant to two or more of the antibiotics tested.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.302-307
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• 1986

In order to investigate the properties of cephalospornase, a strong antibiotic resistant strain(H 112) was isolated from Pseudomonas aeruginose. The extracted enzyme had the following characteristics. Optimum temperature was 45.deg.C and unstable over $55^{\circ}C$, and optimum pH was 8.5. Cephalosporinase activity was not inhibited by metal ions such as $Mn^{++},\;Cu^{++}\;Fe^{++},\;Fe^{+++}$, and EDTA. But it was inhibited by some antibiotics such as carbenicillin, cefoxitin, cefotaxime, cefamandole, cefoperazone and SDS. The Vmax values of the enzyme were 100 at cephaloridine and 2.8 at cefoperazone, respectively. The molecular weight of cephalosporinase was estimated to be about $37.500{\pm}3,000$ by high performance liquid chromatography and nitrocefin reaction.

• Korean Journal of Veterinary Service
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• v.32 no.3
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• pp.215-218
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• 2009

The dog breeding kennel bacterial infection are very significant in perinatal mortality. In many case, Staphylococcus aureus, Streptococcus, and Escherichia coli were infected in intra-uterine or by the genital tract to the puppies, and they are cause of septicemic death of the puppies and clinical mastitis of bitch, leading to septicemic death of newborn puppies. Severe mastitis due to bacterial infection was diagnosed in a 2 year-old female Brittany Spaniel which loss 6 puppies with odor small rice sharp white diarrhea of nine puppies. Bright curd milk and intestinal sample were inoculated on MacConkey agar, blood agar and brain heart infusion agar, and incubated at $37^{\circ}C$ for 24-48 hrs. Gram negative colonies isolated from these sample which were characterized as Glu, Ure, $H_2S$, Orn, Cit, and Cl, and were identified by Microscan Walk-Aways Baxter, American Type Culture Collection, USA) as Proteus mirabils. The isolate was more sensitive to ampicillin, gentamicin, cefoxitin, cefuroxime, and cefazidime. In this results, we confirmed that cause bacteria of septicemic death in puppies was P. mirabilis.

• Korean Journal of Veterinary Research
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• v.50 no.3
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• pp.231-237
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• 2010

This study was conducted to investigate characteristics and antimicrobial susceptibility of Escherichia (E.) coli isolates isolated from vaginal mucosa and clitorial fossa of 105 Thoroughbred mares suspicious of the genital disease in Korea during the period from March 2006 to July 2007. Ninety six E. coli isolates were identified as standard biochemical properties and using BIOLOG system. Fifty three isolates (55.2%) could be classified into a total of 21 O serotypes and forty three isolates (44.8%) were non-typeable with 51 O antisera used in this study. The verotoxin 1 (VT 1) and verotoxin 2 genes were analyzed by multiplex PCR. Among them, one isolate was detected VT 1 gene (130 bp). Most of isolates showed a high susceptibility in ciprofloxacin (100%), enrofloxacin (100%), norfloxacin (100%), cefoxitin (96.9%), gentamicin (96.9%), sulphamethoxazole (96.9%), nitrofurantoin (94.8%), amikacin (93.8%), nalidixic acid (92.7%) and tetracycline (90.6%). These results may provide the basic information to establish strategies for the treatment and prevention of reproductive disease in Thoroughbred mares in Korea.

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.255-261
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• 2010

At the present study, it was aimed to explore the states of antimicrobial resistant Staphylococcus aureus isolates from 320 pigs and cattle carcass (160 pigs and 160 cattle) slaughtered in Busan province from March 2008 to November 2009. Among 320 samples, 26 of Staphylococcus aureus were isolated from pigs (10.6%) and cattle (5.6%). In antimicrobial susceptibility test, all of the isolates were demonstrated susceptibility to oxacillin, cefoxitin, cephalothin, vancomycin, rifampin and linezolid. But the isolates were showed resistance other antibiotics in order of penicillin (92.3%), gentamicin (76.9%), tetracycline (69.2%), erythromycin (65.4%), and clindamycin (61.5%). In case of enterotoxin production, 7.7% of 2 strains produced enterotoxin A.

• Journal of Life Science
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• v.18 no.3
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• pp.369-373
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• 2008

Staphylococcus intermedius (S. intermedius) has been rarely isolated from horse. In this study, we investigated the antimicrobial susceptibility patterns of S. intermedius isolated from skin lesions of Thoroughbred horse in Daegu Equestrian Association. The skin lesions were showed with dehairing and slight purulent inflammation. Bacteria were isolated from skin lesions and identified as S. intermedius by biochemical tests and MicroLog (BIOLOG, California, USA). Antimicrobial susceptibility test of S. intemedius isolates was performed with 33 antimicrobial agents (BBL, Maryland, USA) by using the agar disk diffusion method. It showed a high sensibility in the amikacin, amoxycillin/clavuramic acid, ampicillin, cefoxitin, cephalothin, chloramphenicol, ciprofloxacin, enrofloxacin, florfenicol, kanamycin, neomycin, nitrofurantoin, norfloxacin, ofloxacin, oxacillin, penicillin G, tetracycline and vancomycin. The horse was treated with penicillin, and cured completely after two weeks. The present results showed valuable information for treatment and prevention of skin disease in horse.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.870-877
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• 2020

Twenty-three Bacillus cereus strain isolated from commercial jeotgal were investigated for 11 toxin genes and susceptibility to 25 different antimicrobials. The hemolytic enterotoxins hblA, hblC, and hblD were detected in 13.0%, and non-hemolytic enterotoxins nheA, nheB, and nheC were detected in 26.1%, 100%, and 100% of the isolates, respectively. The positive rates of cytK, entFM, becT, hlyII, and ces were 73.9%, 60.9%, 26.1%, 8.7%, and 0.0%, respectively. According to the disk diffusion susceptibility test, all of the strains studied were resistant to cefuroxime, followed by cefoxitin (78.3%), oxacillin (78.3%), ampicillin (69.6%), penicillin G (69.6%), and amoxicillin (65.2%). However, all the strains were susceptible to 11 other antimicrobials, including amikacin, chloramphenicol, and ciprofloxacin. The average minimum inhibitory concentrations of amoxicillin, ampicillin, and cefuroxime against B. cereus were 462.9, 235.0, and 135.0 ㎍/mL, respectively. These results highlight the need for sanitizing commercial jeotgal, and provide evidence to help reduce the risk of jeotgal contamination by antimicrobial-resistant bacteria.