• Journal of Veterinary Science
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• 제25권1호
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• pp.6.1-6.11
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• 2024

Background: Chronic bovine mastitis is linked to biofilm-producing Staphylococcus aureus (bp-Sa) or Staphylococcus coagulase-negative (bp-Scn). Objectives: Bp-Sa and bp-Scn were treated with intramammary preparations of either enrofloxacin HCl·2H₂O-dimethyl-sulfoxide-chitosan (enro-C/DMSO/chitosan) or enro-C alone. Their potential to inhibit and degrade biofilm formation in vitro was also assessed. Methods: Milk samples were obtained from the affected quarters in a herd. Phenotypical and genotypical identifications as biofilm-producing Staphylococcus species were carried out. Enro-C/DMSO/chitosan and enro-C alone were assessed to determine their in vitro efficacy in interfering with biofilm formation and their bactericidal effects. A prolonged eight-day treatment with a twice-daily intramammary insertion of 10 mL of enro-C/DMSO/chitosan or enro-C alone was set to evaluate the clinical and bacteriological cures on day 10 in 15 cows per group and the biofilm-inhibiting ability. Results: Fifty-seven percent of the isolates were identified as Staphylococcus spp., of which 50% were bp-Sa, 46% bp-Scn, and 4% Staphylococcus pseudintermedius. One hundred percent of the S. aureus isolated and 77% of Staphylococcus coagulase-negative were biofilm producers. In both groups, the icaA and icaD biofilm-producing genes were identified. The experimental preparation could inhibit biofilm formation, degrade mature biofilms, and have well-defined microbicidal effects on planktonic and biofilm bacteria. The respective clinical and bacteriological cure rates were 100% and 80% for enro-C/DMSO/chitosan and 41.7% and 25% for enro-C alone. Conclusions: Enro-C/DMSO/chitosan eliminates bp-Sa and bp-Scn from cases of chronic bovine mastitis.

• 대한의생명과학회지
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• 제7권2호
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• pp.85-89
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• 2001

Many Staphylococcus aureus strains produce enterotoxins causing food poisoning. Staphylococcal enterotoxins are classified by serological criteria into five major groups - subtype A to E. It is difficult, time-consuming, and expensive to detect staphylococcal enterotoxins in the clinical laboratory. In this study, we fried to detect the enterotoxin genes of Staphylococcus aureus strains isolated from clinical specimens and Kimbap - rice rolled in a sheet of laver - using multiplex PCR technique. A total of 77 strains of Staphylococcus aureus from clinical specimens and 78 strains from Kimbap were isolated. Among clinical isolates of S. aureus, 60 strains (78.0%) were identified as producing enterotoxins. A total offs strains (91.6%) in the 60 staphylococcal enterotoxin producing strains were enterotoxin subtype C. In case of kimbap: 43 (55.1%) strains were detected to produce enterotoxins and 39 (90.6%) enterotoxin producing strains were subtype A.

• Journal of Animal Science and Technology
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• 제64권3호
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• pp.515-530
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• 2022

Sequence type (ST) 5 methicillin-resistant Staphylococcus aureus (MRSA) with staphylococcal cassette chromosome mec (SCCmec) type II (ST5-MRSA-II) and ST72-MRSA-IV represent the most significant genotypes for healthcare- (HA) and community-associated (CA) MRSA in Korea, respectively. In addition to the human-type MRSA strains, the prevalence of livestock-associated (LA) MRSA clonal lineages, such as ST541 and ST398 LA-MRSA-V in pigs and ST692 LA-MRSA-V and ST188 LA-MRSA-IV in chickens, has recently been found. In this study, clonotype-specific resistance profiles to cathelicidins derived from humans (LL-37), pigs (PMAP-36), and chickens (CATH-2) were examined using six different ST groups of MRSA strains: ST5 HA-MRSA-II, ST72 CA-MRSA-IV, ST398 LA-MRSA-V, ST541 LA-MRSA-V, ST188 LA-MRSA-IV, and ST692 LA-MRSA-V. Phenotypic characteristics often involved in cathelicidin resistance, such as net surface positive charge, carotenoid production, and hydrogen peroxide susceptibility were also determined in the MRSA strains. Human- and animal-type MRSA strains exhibited clonotype-specific resistance profiles to LL-37, PMAP-36, or CATH-2, indicating the potential role of cathelicidin resistance in the adaptation and colonization of human and animal hosts. The ST5 HA-MRSA isolates showed enhanced resistance to all three cathelicidins and hydrogen peroxide than ST72 CA-MRSA isolates by implementing increased surface positive charge and carotenoid production. In contrast, LA-MRSA strains employed mechanisms independent of surface charge regulation and carotenoid production for cathelicidin resistance. These results suggest that human- and livestock-derived MRSA strains use different strategies to counteract the bactericidal action of cathelicidins during the colonization of their respective host species.

• 한국동물위생학회지
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• 제47권1호
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• pp.27-33
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• 2024

At the present study, it was aimed to explore the states of antimicrobial resistant Staphylococcus aureus isolates from 1,360 chickens, pigs and cattle carcass (400 chickens, 480 pigs and 480 cattle) in Daegu province from January 2022 to December 2022. Among 1,360 samples, 81 of S. aureus were isolated cattle (1.4%), pigs (7.7%) and chickens (9.2%). In antimicrobial susceptibility test, all of the isolates were demonstrated susceptibility to rifampin. But the isolates were showed resistance other antibiotics in order of tetracycline (62.9%), ciprofloxacin (62.9%), tobramycin (58.0%), gentamicin (51.8%), amikacin (40.7%), penicillin (39.5%), clindamycin (35.8%), enrofloxacin (33.3%), trimethoprim/sulfamethoxazole (30.8%), oxacillin (30.8%), minocycline (29.6%), erythromycin (25.9%), quinupristin/dalfopristin (20.9%), chloramphenicol (12.3%), cefoxitin (9.8%). Among the 81 S. aureus isolates, 25 (30.8%) methicillin-resistant staphylococcus aureus (MRSA) were observed. Seven (28.0%) of 25 MRSA harbored mecA gene. About 96% of MRSA were multidrug resistance to at least 3 more drugs. A continuous monitoring and surveillance program to prevent antimicrobial resistance in livestock products is demanded.

• 한국식품위생안전성학회지
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• 제23권2호
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• pp.121-128
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• 2008

본 연구는 Lightcycler (Roche)를 이용한 Real-Time PCR(LC-PCR)기법을 통하여 원유시료에서 신속, 정확하게 황색포도상구균을 검출하는 기법을 개발하고자 하였다. coagulase 전구체를 coding하는 113 bp의 coa 유전자의 증폭, melting curve 분석 및 DNA염기서열을 분석하여 황색포도상구균 특유의 유전자 검출하는 기법을 개발하였다. 또한 분리된 균주중 메치실린에 내성을 나타내는 균주를 검출하고자 penicillin-binding protein, PBP2a (mecA)를 coding 하는 209 bp의 mecA 유전자의 증폭, melting curve 분석 및 DNA염기서열을 분석하여 메치실린내성 황색 포도상구균을 real-time PCR 기법으로 검출하는 기술을 개발하였다. 본 실험에 따르면 647개의 원유시료중 6개의 시료에서 황색포도상구균이 검출되었으며 이중 2개의 시료에서 분리된 황생포도상구균이 메치실린내성 황색포도상구균임을 확인하였다. 또한 DNA 검출한계는 10 fg으로 기존 PCR에 비해 매우 감도가 우수한 것을 확인하였다. 또한 3개의 원유시료에서 돼지나 소의 삼출성 피부염의 원인균인 Staphylococcus chromogenes가 분리되었다.

• 미생물학회지
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• 제47권4호
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• pp.381-385
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• 2011

Methicillin-resistant Staphylococcus aureus (MRSA)는 화농성 질환, 균혈증을 유발하고 병원내 감염의 주요 원인균으로 알려져 있다. 병원에서의 MRSA 분리율은 점차 증가하여 80% 이상으로 보고 되고 있으며 Methicillin 뿐만 아니라 다른 항균제에도 내성을 나타냄으로 치료를 위한 항균제 사용에 제한을 받고 있다. 이에 본 연구에서는 MRSA의 정확한 판정을 통해 항생제 남용을 막고자 대부분의 병원에서 사용하는 항균제 감수성 검사법과 경제적인 면으로 인해 병원내에서 많이 사용되고 있지 않지만 정확도가 높은 mecA 유전자 검출법을 서로 비교하였다. 그 결과 대조군인 Methicillin-susceptible Staphylococcus aureus와 실험군 MRSA 20 균주를 대상으로 항균제 감수성 검사법과 mecA 유전자 PCR 검출법을 실시한 결과 MRSA 20 균주는 Oxacillin과 Cefoxitin에 모두 내성을 나타냈으나 mecA 유전자 검출에서는 20 개 중 17 개에서만 유전자가 검출되어 염기서열분석 결과 mecA 유전자임을 확인하였다. 이런 결과로 보아 mecA(-) 3 균주는 mecA 유전자의 변이로 추측할 수 있기에 임상에서의 MRSA의 판정은 항균제 디스크법과 mecA 유전자 PCR 검출법을 동시에 사용함으로 정확한 MRSA 진단에 도움을 주고자 한다.

• Journal of Microbiology and Biotechnology
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• 제6권3호
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• pp.219-220
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• 1996

The pKH2 isolated from the multidrug-resistant Staphylococcus aureus SA2 is a 40.98-kb plasmid and mediates resistance to ampicillin, clindamycin, erythromycin, kanamycin, and streptomycin. The 3.4-kb HindIII fragment conferring kanamycin resistance was cloned from the pKH2 into pBluescriptII $KS^+$ and partial sequence determination of that fragment was carried out. Sequence analysis revealed that the kanamycin resistance gene which encoded aminoglycoside 3'-phosphotransferase was linked to the streptothricin resistance gene. But a nonsense mutation was found in the streptothricin resistance gene and this mutation resulted in a truncated protein of streptothricin acetyltransferase. Homology comparison with nucleotide sequence databases revealed that the 3.4-kb HindIII fragment of pKH2 had been derived not from S. aureus but from Gram-negative Campylobacter coli.

• Archives of Pharmacal Research
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• 제15권1호
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• pp.99-103
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• 1992

Susceptibility of Psudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis to gentimicin and ceforaxime was affected by salicylaye. In presence of salicylaye (15 mM) and gentamicin (1.0 .mu.g/ml), log efficiency of plating (log E. O. P. s) for the tested bacteria were -1.24, -2.17 and -1.66 respectively. The activity of cefotaxime against Bacillus subtilis was reduced (log E. O. P. = 1.33). The highest potentiating effects of salicylaye were shown when using gentamicin against Staphylococcus aureus, cefotaxime against Ps. aeruginosa, log E. O. P.s were -3.0, and -2.4 respectively. On the other hand, no significant effects were detected with cefotaxime against Staphylococcus aureus (log E. O. P. = -0.04). No significant killing was shown in presence of gentamicin or salicylaye alone. There was no significant effect for salicylaye on MICs (By broth dilution) could be observed except in case of gentamicin against Staphyloccus aureus, which was reduced from 0.02 .mu.g/ml to 0.0012 .mu.g/ml. These results raise the concern that high concentrations of salicylaye in patients might interfere with antibiotic therapies.

• 약학회지
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• 제48권1호
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• pp.30-33
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• 2004

One subfraction from the hexane fraction of Acri graminei Rhizoma, the E4 fraction which is mainly consisted of acorenone, showed a potential inhibitory activity against chloramphenicol acetyltransferase (CAT) of S. aureus SA2 that is a multidrug-resistant strain to 10 usual antibiotics. The combination therapy of this fraction with chloramphenicol resulted in reduction of the minimal inhibitory concentration from 128 $\mu\textrm{g}$/ml to 8 $\mu\textrm{g}$/ml. The E4 fraction also revealed to prevent the induction of CAT from this strain.

• Food Science and Biotechnology
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• 제14권3호
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• pp.311-316
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• 2005

This study was performed to investigate the antimicrobial effect of Sophora angustifolia extracts against food-borne pathogens. First, Sophora angustifolia was extracted with methanol at room temperature, and the methanol extracts from Sophora angustifolia were fractionated using petroleum ether, chloroform, ethyl acetate, and methanol. The antimicrobial activity of the Sophora angustifolia extracts was determined using the paper disc method against food-borne pathogens and food spoilage bacteria. The methanol extracts of Sophora angustifolia showed the highest antimicrobial activity against Staphylococcus aureus and Salmonella typhimurium. A synergistic effect was found in the combined extracts of Sophora angustifolia and Portulaca oleracea, compared to the activity of each extract alone. Finally, the growth inhibition curve was determined using the methanol extracts of Sophora angustifolia against Staphylococcus aureus and Salmonella typhimurium. The methanol extract of Sophora angustifolia showed strong antimicrobial activity against Staphylococcus aureus at a concentration of 5,000 ppm. The 5,000 ppm methanol extract from Sophora angustifolia retarded the growth of S. aureus for more than 24 hours and of Salmonella typhimurium for up to 12 hours.