• Journal of Veterinary Science
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• 제23권6호
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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.

• 한국동물위생학회지
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• 제36권4호
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• pp.249-254
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• 2013

This study was done to determine the seroprevalence of Coxiella burnetii in cattle with reproductive disorders reared in eastern Gyeongbuk province. A total of 146 cattle blood samples from 83 farms in eastern Gyeongbuk province were collected in 2011~2012. Among them, 17 (11.6%) samples from 11 (13.3%) farms were seropositive for C. burnetii by ELISA. In dairy cattle with mastitis, 15 (38.5%) milk samples from 9 (42.9%) farms were seropositive among 39 milk samples from 21 farms. Among the seropositive farms, one farm with high seroprevalence was selected to assess the seroprevalence of C. burnetii in the bulk-tank milk (BTM) and blood samples of dairy cattle. The BTM sample from the farm was seropositive to C. burnetii and 6 (15%) out of 40 dairy cattle were seropositive. In cattle with reproductive disorders including infertility, abortion and stillbirth, 2 (1.9%) samples from 2 (3.2%) farms were positive among 107 samples collected from 62 farms. Among 2 positive samples, one of them is dariy cattle (100%) and the other is Korean cattle (0.9%) (P<0.001). This suggests that Korean cattle was relatively resistant to C. burnetii. Based on the data obtained, we identified association between C. burnetii shedding in milk and chronic subclinical mastitis in dairy cattle. Since seroprevalence of C. burnetii is relatively high in dairy cattle, further intensive studies on C. burnetii among the high risk milk farms and dairy cattle herds are needed to evaluate infection status.

• 대한수의학회지
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• 제58권1호
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• pp.51-55
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• 2018

Bovine mastitis (BM) has resulted in enormous economic loss in the dairy industry and coagulase-negative staphylococci (CNS) have caused subclinical BM. Although VITEK 2 GP ID card (VITEK 2) has been used for CNS identification, the probability of identification varies. The rpoB sequence typing (RSTing) method has been used for molecular diagnosis and epidemiology of bacterial infections. In this study, we undertook RSTing of CNS and compared the results with those of VITEK2 and 16S rRNA gene sequencing. As compared VITEK2, the molecular-based methods were more reliable for species identification; moreover, RSTing provided more molecular epidemiological information than that from 16S rRNA gene sequencing.

• Asian-Australasian Journal of Animal Sciences
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• 제23권10호
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• pp.1319-1324
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• 2010

The objectives of this study were to compare the effectiveness of different indicators of mammary inflammation in buffalo and to evaluate the association of the indicators with buffalo milk yield, composition, and rennet coagulation properties. This study was carried out at four buffalo farms in central Italy using a total of 50 lactating buffalo. Milk from each buffalo was tested at the beginning, middle, and end of lactation. To evaluate the relationship between mastitis markers and milk components, three classes were defined for each of the following markers: total somatic cell count (TSCC), differential somatic cell count (DSCC), and bacteriological results The regression coefficient for the reference method and the alternative method of determining TSCC was 0.81, indicating that the method routinely used to analyze buffalo milk consistently underestimated actual TSCC. The milk samples positive for udder-specific bacteria also had higher TSCC values than the samples that were negative for bacteria ($872{\times}10^3$/ml vs. $191{\times}10^3$/ml). In samples that were positive for udder-specific bacteria, polymorphonuclear leukocytes (PMN) made up greater than 50% of the cells. Moreover, only 1% of the samples in the lowest TSCC class were positive for bacteria. The correlation between TSCC and PMN was stronger (0.70), and PMN values in buffalo milk increased significantly when the TSCC class changed from low (38%) to medium and high (56% and 64%). Milk yield was negatively related to TSCC. Significant changes in lactose (4.87%, 4.80% and 4.64%) and chloride content (0.650 mg/ml, 0.862 mg/ml and 0.882 mg/ml) were also observed with increasing TSCC values. Higher TSCC was associated with impaired rennet coagulation properties: the clotting time increased, while the curd firming time ($p{\leq}0.05$) and firmness decreased. We concluded that in buffalo as in dairy cows, TSCC is a valid indicator of udder inflammation; we also confirmed that a value of $ 200{\times}10^3 cells/ml should be used as the threshold value for early identification of an animal affected by subclinical mastitis. In addition to its association with significantly decreased milk yield, a TSCC value above this threshold value was associated with changes in milk composition and coagulating properties.

• 한국임상수의학회지
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• 제10권2호
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• pp.147-155
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• 1993

This study was carried out to investigate the Preventive and treatment effects of mixed compound of vitamin E and selenium, and ursodeoxycholic acid on the pre-parturient and post-parturient fatty liver of high. yielding dairy cows. Thirty pregnant dairy cows(2 weeks preparturition) were divided into clinical(13cows) and subclinical(17 cows) groups based upon blood chemical values, blood serum protein levels and clinical symptoms. The clinical group was subdivided into treated clinical group(6 cows) and non-treated clinical group(7 cows). The cows(treated clinical group) with fatty liver diagnosed before parturition were dosed with mixed compound of vitamin I(1head) and selenium(10mg/head) intramuscularly once before and after parturition, respectively. These cows(treated clinical group) were also given ursodeoxycholic acid(50g/head) intramuscularly 3 times before parturition. The cows(treated clinical group) with fatty liver diagnosed after parturition were also given the same compounds as dosed to the above cows at same dose rate once or 3 times, respectively after parturition. Blood samples were collected from the cows on 4th, 7th and 2nd day of preparturition and on 1st, 7th, 14th and 20th day of postparturition. Blood chemical values(non-esterified fatty acid : NEFA) concentration, serum aspartate aminotransferase activity, serum ${\gamma}$-glutamyl transpeptidase activity, bilirubin concentration, glucose level) were checked and clinical symptoms of the cows were also observed. 1. The cows in non-treated clinical group showed severe depression, anorexia and diarrhea from prepartum period, and retained palcenta, endometritis, ketosis, abomasal displacement and mastitis after parturition. Cows in treated clinical group showed moderate depression, anorexia, diarrhea during preparturient period, but they were relieved within a week from parturition. Cows in subclinical group showed mild depression, anorexia and diarrhea after parturition, but these symptoms were not observed in prepartum period. 2. NEFA concentration, serum aspartate aminotransferase activity, serum ${\gamma}$-glutamyl transpeptidase activity and bilirubin concentration observed In the cows of treated clinical group were significantly lower than those of the cows non-treated clinical group. The blood glucose concentration of the cows in treated clinical group were higher than those of the cows in non-treated clinical group. These results indicate that the preparturient and postparturient fatty liver of high-yielding dairy cows could be reduced by dosing the animals with appropriate amounts of mixed compound of vitamin I and selenium, and ursodeoxycholic acid at proper times of the preparturition and postparturition of the dairy cows.

• 대한수의학회지
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• 제29권1호
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• pp.69-73
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• 1989

준임상형 유방염 이환 젖소의 유즙과 유두컵으로부터 분리된 Candida속 균의 8종 항진균성약제에 대한 감수성을 조사하였던 결과는 다음과 같다. 총 53주의 Candida속균 중 98.2%, 94.4%, 84.8%의 균주가 각각 clotrimazole, econazole, miconazole의 농도 $25{\mu}g/ml$이하에서 발육이 억제됨으로서, 이들 약제의 항균력이 타 약제에 비하여 우수하였다. 균종별로 보면 C albicans는 clotrimazole에 대한 감수성이 가장 높았으며, 기타 비교적 감수성이 높았던 약제는 5-fluorocytosine, econazole, miconazole의 순이었다. C pseudotropicalis와 C guilliermondii는 haloprogin, clotrimazole, miconazole, econazole, 5-fluorocytosine등에 높은 감수성을 나타내었으며, haloprogin의 평균 MIC가 $0.17{\sim}0.19{\mu}g/ml$로 가장 우수하였다. C krusei는 cycloheximide에 대한 감수성이 가장 높았으며, 그의 비교적 감수성이 높았던 약제는 clotrimazole, haloprogin, miconazole, econazole의 순이었다. 한편 C parapsilosis는 econazole, cycloheximide, clotrimazole등에 다소 감수성을 나타내었으나, 이들 약제의 MIC는 econazole(기하평균 MIC $7.26{\mu}g/ml$)을 제외하고는 타균종에서 보다 현저히 낮았다. 또한 C tropicalis는 전 공시약제에 대하여 감수성이 낮은 경향이었다.

• 대한수의학회지
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• 제19권1호
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• pp.75-83
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• 1979

The sensitivities of 270 pathogens (124 Streptococci, 118 Staphylococci, 10 Corynebacterium pyogenes and 18 Escherichia coli) isolated from clinical or subclinical cases of bovine mastitis during lactation to 11 antibiotics were determined by the agar plate dilution method. All cultures of Streptococci were inhibited at $1.56{\mu}g/ml$ of ampicillin and 1.56 units/ml of penicillin G. Most of the cultures were inhibited at $3.125{\mu}g/ml$ of leukomycin, but were resistant to kanamycin, streptomycin, chloramphenicol, erythromycin and colistin at concentration of $12.5{\mu}g/ml$. More than 93% of the Staphlococcal cultures were sensitive to kanamycin, leukomycin, ampicillin, tetracycline, ledermycin and minocycline at concentrations of $12.5{\mu}g/ml$ or less, and sensitive to penicillin at concentration of 3.125 units/ml, but for more than 71% of the cultures to chloramphenicol, erythromycin and colistin the concentrations required to inhibit growth were 100 ${\mu}g/ml$ or higher. All 10 cultures of Corynebacterium pyogenes were inhibited by leucomycin, ampicillin and minocycline at concentration of $1.56{\mu}g/ml$ and by penicillin G at concentration of 0.78 units/ml, but all the cultures required at least $400{\mu}g/ml$ or higher of streptomycin, erythromycin and colistin for inhibition. More than 83% of E. coli cultures were sensitive to erythromycin and minocycline at concentration of $12.5{\mu}g/ml$, but resistant to leucomycin and chloramphenicol at concentration of $100{\mu}g/ml$.

• 대한수의학회지
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• 제28권2호
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• pp.361-363
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• 1988

진주근교에서 효모균에 의한 젖소의 준임상형 유방염 발생상황과 이들균의 유두컵내의 오염상태를 조사하였던 결과는 다음과 같다. 총 검사분방 330개 중 12분방으로부터 효모균이 분리되어 이로인한 준임상형 유방염의 발생율은 3.6%이었다. 분리균 12주는 Candida pseudotropicalis 4주, C tropicalis 3주, C krusei 2주, C albicans 2주 및 Rhodotorula spp 1주로 동정되었으며, 분리균의 91.7%가 Candida속 균이었다. 유두컵 200개 중 20.5%로부터 C. pseudotropicalis 13주, C guilliermondii 9주, C tropicalis 7주, C krusei 5주, C parapsilosis 5주, C albicans 3주, Torulopsis glabrata 2주, Geotrichum candidum 2주 및 미동정 효모균 5주가 분리되었다.

• Journal of Veterinary Science
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• 제23권1호
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• pp.9.1-9.11
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• 2022

Background: Escherichia coli, which causes subclinical or clinical mastitis in cattle, is responsible for transmitting antimicrobial resistance via human consumption of raw milk or raw milk products. Objectives: The objective of this study was to investigate the molecular characteristics of 183 E. coli from bulk tank milk of five different dairy factories in Korea. Methods: The molecular characteristics of E. coli such as serogroup, virulence, antimicrobial resistance, and integron genes were detected using polymerase chain reaction and antimicrobial susceptibility were tested using the disk diffusion test. Results: In the distribution of phylogenetic groups, group D was the most prevalent (59.6%) and followed by group B1 (25.1%). The most predominant serogroup was O173 (15.3%), and a total of 46 different serotypes were detected. The virulence gene found most often was fimH (73.2%), and stx1, fimH, incC, fyuA, and iutA genes were significantly higher in isolates of phylogenetic group B1 compared to phylogenetic groups A, B2, and D (p < 0.05). Among 64 E. coli isolates that showed resistance to at least one antimicrobial, the highest resistance rate was observed for tetracyclines (37.5%). All 18 integron-positive E. coli carried the integron class I (int1) gene, and three different gene cassette arrangements, dfrA12+aadA2 (2 isolates), aac(6')-Ib3+aac(6')-Ib-cr+aadA4 (2 isolates), and dfrA17+aadA5 (1 isolate) were detected. Conclusions: These data suggest that the E. coli from bulk tank milk can be an indicator for dissemination of antimicrobial resistance and virulence factors via cross-contamination.

• 한국환경보건학회지
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• 제11권2호
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• pp.41-54
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• 1985

This study was conducted for the improvement of milk quality and milk hygiene in public health point of view. Investigation of mastiris infection rate, isolation and identification of causative microorganisms in CMT positive milk, investigation of milk contamination level by measuring the bacteria and soma tic cell counts and investigation of dairy management in farms were performed on 1.605 quarters milk of 434 cows of 20 dairy farms in Gyunggi-area from September 1983 to March 1984. The results were summarized as follows 1. Sixteen (3.7%) of 434 cows were found to be infected with clinical mastiris. 234 (53.9%) of 434 cows and 608(37.9%) of 1, 605 quarters were found to be infected with subclinical mastiris. 2. The causative microorganisms isolated were Staphylococcus aureus (38.3%), Staphylococcus epidermidis(21.0%), Micrococci(13.6%), Streptococcus spp. (12.3%), E. coli (7.4%), Fungus & Yeast (1.6%) and others (5.8%). 3. Total numbers of bacteria were $9.2{\times}10^6$ to $1.21{\times}10^7/ml$(av. $1.805{\times} 10^7/ml$), numbers of coliform bacteria were $4.1{\times} 10^5$ to $9.4{\times} 10^5$/ml(av. $7.05{\times} 10^5$/ml) and somatic cell counts were $4.8{\times} 10^5$ to $1.52{\times} 10^6$ cells/ml (av. $9.5{\times} 10^5$cells/ml) in bulk milk. 4. As comparing with CMT score of +, ++ and +++, somatic cell counts were $3.4{\times} 10^5$ to $1.64{\times} 10^6$ cells/ml (av. $6.41{\times} 10^5$cells/ml), $5.4{\times} 10^5$ to $2.75{\times} 10^6$ cells/ml(av. $1.762{\times} 10^6$cells/ml) and $1.97{\times} 10^6$ to $9.75{\times} 10^6$ cells/ml(av. $7.781{\times} 10^6$cells/ml), respectively. 5. In investigation on dairy management, performance of dry cow therapy, teat dipping after milking, disinfection of milking machine at every milking, replacement of milk liner within 6months and opportunity of acquirement for the mastiris control techniques by dairy education were 65%, 40%, 45%, 55% and 50% in 20 dairy farms, respectively.