• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.193-199
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• 1983

The authors carried out bovine mastitis test by California Mastitis test (CMT) for the milk from dairy cows in the suburbs of Daejeon. Among the CMT positive milk, Staphylococcus aureus were isolated and, for the proper selection of the commercial antibacterial agents, the strains were tested for the resistant test to the agents. The results obtained were summarized as follows. 1. The resistant test appeared graduate resistance is in such cases continuously repeat with the therapeutic antibacterial agents. 2. The result of resistant test appeared the weakly resistance, untill 4 times subculture in the Rifamastene, Neo-cillin, and 6 times in the Abimasten-100, Neo-masti, Special formular and mastalone. 3. In Tardomycel-L there was rare resistant reactions, untill 6 times subculture. 4. The author recommend that select the antibacterial agents by resistant test and use the selective agents in turn.

• Journal of Preventive Medicine and Public Health
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• v.38 no.4
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• pp.482-488
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• 2005

Objectives : We conducted an investigation on 14 cases of brucellosis in Gyeongsangbuk-do during 2003-2004 to understand the source of infection and the transmission routes of brucellosis. Methods : The authors visited the each of the health centers and we examined the patients, their written epidemiologic questionnaire and the occurrence of bovine brucellosis. We visited the patients' living and work areas, and we examined their occupations, the date they developed symptoms, the progress of their symptoms, whether or not they were treated, their current status, whether or not they consumed raw milk and raw meat, and if their work was related to cattle breeding and the related details. We reviewed the results of the blood tests and medical records and we examined the cattle's barn. Results : There were 3 patients in 2003 and 11 patients in 2004. All of their brucella antibody titer exceeded 1:160. The patients' symptoms were fever, myalgia, malaise, chills and an influenza-like illness, but the clinical signs were absent on the medical records. Brucella abortus were cultured from 3 of the patients' blood samples. Conclusions : When the authors discovered the transmission routes, they were divided into 4 different sorts. The first route was related to cattle birth such that patients touched the calves or placentas that were infected with the Brucella species. The second route was related to performing artificial insemination on the cattle and the semen that was used for artificial insemination. The third route was due to the ingestion of raw meat and milk. The last route was due to sexual intercourse between the patients.

• Korean Journal of Veterinary Research
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• v.52 no.2
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• pp.69-74
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• 2012

The analytical method of trace toxic metals in livestock products was confirmed and validated through certified reference material (CRM) and the international proficiency tests. There are some difficulties to determine low levels of toxic metals in livestock products because of interferences due to the matrix. The recoveries of CRM (NIST 1577c) ranged from 73.9 to 119% for lead and from 86.4 to 111% for cadmium in bovine liver. The international proficiency tests were carried out with the milk powder and cocoa powder samples including metals provided by Food Analysis Performance Assessment Scheme (FAPAS$^{(R)}$, UK). The test samples were prepared by microwave digestion using solution of $HNO_3:H_2O_2:H_2O$ (v/v/v = 5 : 2 : 4) and analyzed by ICP/MS. The analytical result of cadmium in milk powder was $121{\mu}g/kg$ with -0.3 of the z-score compared to the assigned value of $131{\mu}g/kg$ by FAPAS$^{(R)}$. The analytical results of lead and cadmium in cocoa powder were $29.2{\mu}g/kg$ and $97.6{\mu}g/kg$, respectively, which satisfied the assigned values of $34.2{\mu}g/kg$ for lead and $126{\mu}g/kg$ for cadmium by FAPAS$^{(R)}$. It is verified that the analytical method is accurate and reliable to determine trace lead and cadmium in livestock products by microwave digestion and ICP/MS.

• Korean Journal of Veterinary Research
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• v.52 no.3
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• pp.169-176
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• 2012

Probiotics colonize the intestines and exert an antibacterial effect on pathogens. Therefore, probiotics could be used as a preventive agent against lethal infections. To isolate probiotic microorganisms, 116 bacterial strains were isolated from healthy cow's milk and were subjected to Gram-stain, morphology and biochemical analyses, Vitek analysis, and 16S rRNA analysis. One of the strains identified as Bacillus (B.) thuringiensis 87 was found to grow very well at pH 4.0~7.0 and to be resistant to high concentrations of bile salts (0.3~0.9% w/v). B. thuringiensis was susceptible to the antibiotics used in the treatment of bovine mastitis, yet it exhibited an antimicrobial effect against Staphylococcus (S.) aureus 305. Moreover, it protected mice from experimental lethal infections of E. coli O55, Salmonella typhimurium 01D, and S. aureus 305 through a significant induction of interferon-${\gamma}$, even at four-week post-administration of B. thuringiensis. Although oral administration of B. thuringiensis 87 did not provide significant protection against these lethal challenges, these results suggest that B. thuringiensis 87 could be a feasible candidate as a probiotic strain.

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.2
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• pp.137-142
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• 2007

The antibacterial activity of Korean honey bee venom (KBV) was examined against seven major bacterial mastitis pathogens, Enterococcus faecium, Escherichia coli, Methicillin resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Streptococcus intermedius, Streptococcus oralis and Streptococcus uberis isolated from infected mammary quarters of cows. Seven bacterial mastitis pathogens were studied for antibacterial activity of the KBV by disc diffusion assay, minimal inhibitory concentrations (MIC) and bacterial count in milk samples. The KBV showed activity against Ent. faecium, E. coli, MRSA, Staph. aureus, Strep. intermedius. The order of susceptibility of the bacteria against the KBV was Staph. aureus>MRSA>E. coli>Strep. intermedius>Ent. faecium>Strep. oralis>Strep. uberis. The MIC against Staph. aureus, MRSA and E. coli were stronger effect as compared with standard drug. The effect of the KBV ($100{\mu}g\;ml^{-1}$) on the viability of Ent. faecium, E. coli, MRSA, Staph. aureus, Strep. intermedius, Strep. oralis and Strep. uberis in milk differed significantly with each other within 12 h incubation period. The results indicate that KBV has significant antibacterial effects against major bacterial mastitis bacteria, Ent. faecium, E.coli, MRSA, Staph. aureus, Strep. intermedius. Results of the study indicate the potential use of KBV as alternative to antibiotic therapy. Further investigations are needed though to confirm its efficacy and its effects on the animals.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.391-397
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• 2020

Human infections with livestock-associated methicillin-resistant/-susceptible Staphylococcus aureus (LA-MRSA/LA-MSSA) have recently been increasing significantly. These LA-MRSA and LA-MSSA strains can be transmitted to individuals who have frequent contact with livestock animals and foods of animal origin. In this study, major virulence potentials of S. aureus such as biofilm formation, antimicrobial peptide resistance, and in vitro hydrogen peroxide (H₂O₂) resistance were assessed using 20 MRSA and MSSA strains isolated from raw milk, beef cattle, and workers in the livestock industry. Static biofilm formation assays revealed that there is no difference in levels of biofilm production between MRSA versus MSSA or bovine- versus human-associated strains. In vitro BMAP (bovine myeloid antimicrobial peptide)-28 susceptibility assays also revealed no difference in the resistance to the antimicrobial peptide between MRSA versus MSSA or bovine- versus human-associated S. aureus strains. However, LA-MRSA strains displayed increased resistance to H₂O₂, which may play an important role in survival and dissemination of the pathogen in livestock. These results provide an important basis for understanding pathogenic potentials of LA-MRSA and LA-MSSA strains in human and animal hosts.

• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.177-188
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• 2001

Mastitis is one of the most significant cause of economic loss to the dairy industry. Especially, Staphylococcus aureus is a major contagious mastitis-causing pathogen in dairy cattle. Because of its high transmission rate and resistance to antibiotic therapy, staphylococcal mastitis presents a constant threat to the dairy industry. Staphylococcal enterotoxin C(SEC) produced by S aureus has been known as one of superantigens which are able to stimulate a large proportion of T lymphocytes independently of their antigenic specificity. In this experiment, we have conducted preliminary studies with mice and lactating cows to evaluate the immunogenicity and safety of the experimental vaccine consists of SEC mutant antigen on controlling the bovine mastitis associated with S aureus infections. The average value of somatic cell counts in quarter milk, isolation rate of S aureus were consistently decreased in SEC-SER vaccinated groups, whereas antibody titers were highly increased in SEC-SER vaccinated groups. Peripheral blood were also collected from the lactating cows to determine the proportion of leukocyte subpopulation associated with humoral immunity(HI) and cell mediated immunity(CMI). Proportion of leukocyte subpopulation expressing $BoCD2^+$(total T lymphocyte), $BoCD4^+$(T helper cell), $BoCD8^+$(T cytotoxic/suppressor cell) and NonT/NonB lymphocyte which are involved in CMI in SEC-SER vaccinated groups were decreased for the initial stage after first vaccination and then increased from ten weeks after first vaccination maintaining elevated level till 14 weeks after vaccination. In contrast, proportion of monocyte, MHC class II and B lymphocyte which are associated with the production of primary immune response in SEC-SER vaccinated groups were increased for the initial period and then decreased from ten weeks after first vaccination. We present evidence that vaccination of SEC-SER mutant antigen in lactating cows induced a significant proliferation of bovine T lymphocytes. These results suggest that SEC-SER mutant antigen used in this experiment might be one of potential immunogen in developing innovative vaccine against bovine IMI associated with S aureus. Additional challenge trials should be carried out to evaluate substantial protection against S aureus under the commercial farm conditions.

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.379-388
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• 2011

Survey of mastitis management and incidence of mastitis in the Gyeongnam was started in May to September 2009 to solve mastitis problem statistically valid data for use in estimating mastitis management, isolation and antimicrobial drug susceptibility in 30 dairy farms having over 350,000/ml somatic cell count. In investigation on recognition of farmer about bovine mastitis, the ratio of understanding of differences between infectious and environmental origin, understanding of correlation between superbacteria and using indiscriminate, necessity of pathogen identification, and necessity of antimicrobial sensitivity tests were 80.0%, 73.3%, 33.3%, and 53.3%, respectively. In survey of mastitis management type, regular california mastitis test (CMT), conducting CMT test and empirical self-treatment, when detecting suspected cows, were 30.0%, 40.0%, and 46.7%, respectively. Checking and cleaning pulsators biweekly, cleaning vacuum system and replacing liners every 3~6 month, and getting milking system checked by engineers showed 80.0%, 76.7%, and 76.7% in the questionnaires, respectively. In recognition of farmer about milking hygiene for prevention of bovine mastitis, using individual towels, separated milking (milking order of cows), and teat-dipping disinfection after milking exhibited 13.3%, 86.7%, and 93.3%, respectively. In conclusion, through the questionnaires and laboratory test, we suggest that recognition of farmer about management and incidence of mastitis was very low, thus systemic educational program and public relations about mastitis management were need for dairy farmers.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.667-672
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• 2011

This study was carried out to increase the breeding rate using sustained recombinant bovine somatotropin (bST) and examine the reproductive disorder and disease prevalencies of cow and calf, respectively. Sixty cows were allotted randomly to three groups in randomized complete block design; (1) No treatment, (2) 500 mg bST two times + 250 mg bST SC injection five times from 3 weeks before to 9 weeks after parturition every two weeks, (3) 500 mg bST two times before 3 weeks parturition + 250 mg bST SC injection three times from five to 9 weeks after parturition every two weeks. Developmental data of birth weight, weaning weight, total gain and average daily gain in control was $22.9{\mu}0.45$ kg, $88.0{\mu}1.13$ kg, $65.1{\mu}0.74$ kg and $0.54{\mu}0.08$ kg, respectively. There is no significant difference between Group 1 and 3 in the examined factors. However, there is significant difference between Group 1 and 2 in the birth weight ($24.4{\mu}0.88$ kg), weaning weight ($101.0{\mu}1.77$ kg), total gain ($76.7{\mu}0.9$ kg) and average daily gain ($76.7{\mu}0.9$ kg). Total gain was showed higher in Group 2 and 3 than Group 1 in the >2nd parity, and in Group 2 than Group 1 and 3 in the 1st parity. There is no significant difference in the BCS, no return days and disease occurrence of cow and calf by bST treatment. Number of service per conception was slightly increased in the Group 3 compared to Group 1 and 2. To increase the breeding ability of Hanwoo, it is recommended that 500 mg bST two times + 250 mg bST injection five times from 3 weeks before to 9 weeks after parturition every two weeks.

• Journal of Veterinary Science
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• v.21 no.5
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• pp.77.1-77.14
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• 2020

Background: Staphylococcus aureus is one of the main microorganisms that causes bovine mastitis, and its well-known virulence characteristics and interactions with the environment are used to aid the design of more efficient therapies. Objectives: To determine whether the virulence traits, such as antibiotic resistance and biofilm-forming and internalization abilities, of S. aureus isolated from bovine mastitis are related to dairy production system types. Methods: The study was performed in the Mexican states of Guanajuato and Michoacan. Semi-intensive dairy farms (SIDFs) and family dairy farms (FDFs) (454 and 363 cows, respectively) were included. The 194 milk samples from mastitis affected quarters were collected and 92 strains of S. aureus were isolated and identified by biochemical and molecular tests. Antibiotic resistance, biofilm and internalization assays were performed on 30 randomly selected isolated strains to determine virulence traits, and these strains were equally allocated to the 2 dairy production systems. Results: All 30 selected strains displayed a high degree of resistance (50%-91.7%) to the antibiotics tested, but no significant difference was found between SIDF and FDF isolates. S. aureus strains from SIDFs had an average biofilm forming capacity of up to 36% (18.9%-53.1%), while S. aureus strains from FDFs registered an average of up to 53% (31.5%-77.8%) (p > 0.05). Internalization assays revealed a higher frequency of internalization capacity for strains isolated from FDFs (33.3%) than for those isolated from SIDFs (6.7%) (p > 0.05). fnbpA gen was detected in 46.6% of FDF strains and 33.3% of SIDF strains, and this difference was significant (p < 0.05). Conclusions: Our findings show that the virulence traits of S. aureus isolates analyzed in this study, depend significantly on several factors, such as phenotype, genotype, and environmental conditions, which are significantly related to dairy production system type and daily management practices.