2017年上海、河北地区奶牛乳房炎克雷伯菌分离鉴定及耐药性分析

为了摸清上海和河北地区奶牛乳房炎的主要致病菌克雷伯菌的分离率及其耐药情况,对采集自上海和河北两地的乳房炎患病奶牛乳样进行克雷伯菌的分离培养和形态学、分子生物学鉴定,并选择临床常用的抗生素对分离得到的克雷伯菌进行药敏试验。经革兰染色、镜检以及分子生物学鉴定发现,采集自上海地区的100份乳房炎患病奶牛乳样中有18份乳样存在克雷伯菌,分离率为18%;采集自河北地区的100份乳房炎患病奶牛乳样中有14份乳样存在克雷伯菌,分离率为14%;且上海和河北地区2017年下半年乳房炎患病奶牛乳样中克雷伯菌分离率均高于上半年。药敏试验结果表明,该试验分离得到的克雷伯菌对所测试的抗生素存在不同程度的耐药性,其中,单一耐药菌株占21.88%,多重耐药菌株占53.13%,全部敏感的菌株占12.50%。由该试验结果可以得出,上海、河北地区奶牛发生的乳房炎是与克雷伯菌感染有关;且分离得到的克雷伯菌对临床常用的抗生素存在不同程度的耐药性。在动物生产和兽医临床上应及时监控克雷伯菌的流行趋势和耐药性变迁,并合理使用抗生素以减少耐药菌株的产生。     

银川地区牛乳中头孢类药物与庆大霉素残留的检测

抗生素残留一直是威胁食品安全的重大问题,为了解银川地区牛乳中抗生素残留情况,采用间接竞争酶联免疫吸附试验(ELISA),对银川地区部分养殖场和超市共计350份乳样进行了头孢类药物和庆大霉素残留的检测。结果显示,来自养殖场的200份乳样中,有4份样品的头孢类药物检测结果不合格,5份样品的庆大霉素检测结果不合格,分别占检测样品的2%和2.5%。来自超市的150份乳样中,有3份样品的头孢类药物检测结果不合格,2份样品的庆大霉素检测结果不合格,分别占检测样品的2%和1.3%。说明在银川地区部分养殖场和超市的牛乳中均存在头孢类药物和庆大霉素残留超标的问题。     

吉林省敦化地区部分牛乳抗生素残留调查分析

应用国际标准(GB-TTC)法对吉林省敦化市市郊散养奶牛新鲜牛乳进行抗生素残留的实验室检测。结果发现,62份牛乳中15份牛乳有抗生素残留,占24.1%。因此,建议敦化市养殖户应加强饲养管理,并严格遵守休药期规定,以减少奶牛疾病的发生,从而保证消费者的健康。     

宁夏地区奶牛乳房炎源阴道加德纳菌分离鉴定及耐药性分析

为了研究奶牛乳房炎源阴道加德纳菌(GV)的耐药情况,从宁夏部分奶牛场采集临床型乳房炎奶牛乳样94份、隐性乳房炎奶牛乳样70份进行细菌分离鉴定,得到2株GV(均来自于临床型乳房炎奶牛乳样);动物试验结果表明GV对奶牛乳房炎没有致病性;药敏试验结果表明分离菌对哌拉西林、万古霉素、四环素、克林霉素耐药,对阿莫西林中介,对其他药物均敏感。     

乳房炎源生鲜乳中病原微生物的污染现状及防控措施

主要介绍了乳房炎患病牛乳中病原微生物污染情况、耐药情况及防控措施。总结出乳房炎患病牛乳中的病原微生物种类较多, 主要有大肠杆菌、金黄色葡萄球菌、链球菌和克雷伯菌, 不同地区乳房炎乳样中的病原微生物不同, 产生的耐药性和耐药基因存在差异。旨在为减少因滥用和乱用抗生素导致药物残留和耐药性产生、降低乳房炎患病牛乳中病原微生物的污染以及科学、合理用药提供参考。     

牛乳中抗生素的残留及其控制对策

乳品中残留的抗生素不仅危害人体的健康,也会对乳制品行业造成影响。针对牛乳中抗生素的残留来源、种类、危害、检测方法进行了综述,并探讨控制牛乳中抗生素残留的对策。     

ECLIPSE 50试剂盒检测生鲜牛乳中抗生素残留结果误判的研究

选用ECLIPSE 50试剂盒检测生鲜牛乳中抗生素残留,实验发现生鲜牛乳pH值下降对抗生素残留接近试剂盒检出限时易产生假阴性结果,初乳易产生假阳性结果,是否预热处理对检测结果无直接影响。     

新疆昌吉加大力度做好奶站检测工作

2013年,新疆昌吉市加大了全市畜产品检测力度。在生鲜牛乳的检测工作中,对全市25家具有生鲜牛乳收购许可证的生鲜乳收购站进行了定期、不定期抽样检测。检测项目包括：分析乳成分达标否,检测牛奶是否掺碱,是否含有三聚氰胺,是否存在抗生素残留,是否添加解抗剂等。通过检测加大了对全市奶站的监督管理,确保人民群众喝上健康无污染的牛奶。截至到2013年10月底,共检测牛奶650余份,未检出三聚氰胺,检出抗生素残留牛奶11份、解抗剂牛奶3份、掺碱牛奶2份。     

西宁市售鲜牛乳中抗生素残留情况调查

采用TTC法对西宁市售 77份鲜牛乳样品进行抗生素残留检验 ,验出抗生素阳性乳 9份 ,抗生素残留率为 11 7%     

有抗奶的危害及控制措施

<正>我国对生鲜牛乳收购有明确的标准(GB/T6914-86),但其中只对理化指标、感官指标、细菌指标有明确的规定和检验方法,而对牛奶中抗生素残留卫生指标无明文规定,"有抗奶"是指抗生素残留超标的牛奶。2001年10月份,农业部发布实施了《无     

应用TTC法检测牛奶中磺胺类残留的试验

利用嗜热链球菌为菌种检验牛奶中抗菌素残留的氯化三苯基四氮唑法（TTC法），是我国的国家标准方法。本研究尝试利用TTC法检验鲜乳中磺胺类药物残留，结果发现检验的灵敏度很低，检出限高于国外对其残留控制标准。说明TTC法不能用于精确检验鲜乳中磺胺类药物残留是否超过最高限量（0．1mg／kg）。     

抗菌药物治疗奶牛子宫内膜炎后牛奶中药物残留及其对酸奶发酵的影响

用TTC法检测44例经过抗菌药物治疗的患子宫内膜炎荷斯坦奶牛。其中，41例采用子宫内灌注药物治疗，主要药物有土霉素、金霉素和庆大霉素；每个病例治疗1～5次不等，3例采用静脉注射，主要药物有磺胺嘧啶钠和头孢噻啶。结果表明，31例经土霉素子宫内灌注的奶牛，停药后第24h所采的奶样均可检出抗生素；其中6头奶牛在第6d仍然抗生素阳性，残留时间最长的可达8d。8例用金霉素子宫灌注治疗的奶牛，停药后第48h所采的奶样，抗生素检出率100％，其在牛奶中的残留时间为2～5d不等。2例经庆大霉素子宫灌注治疗的患病牛，药残时间分别为1～2d。3头经静脉滴注治疗的病牛，牛奶中的药残时间约达到9d以上。此外，从3头用金霉素子宫内灌注的奶牛采集牛奶用于乳酸菌发酵试验。结果表明，牛奶TTC阳性时，发酵产酸较低。在治疗后6h采集的牛奶都不能正常发酵产酸、凝固。3例试验牛牛奶发酵产生的酸度分别于治疗后第13、24和48h恢复到治疗前的水平。     

鲜牛奶中抗生素残留的检测

随机采取市售鲜牛奶250份,采用TTC法进行抗生素残留检测。表明:检出有抗生素残留的阳性乳2份,均为西宁市区产品,阳性率占0.8%,其余248份均为阴性,无抗生素残留。     

Prevalence of and resistance to anti-microbial drugs in selected microbial species isolated from bulk milk samples

The prevalence of strains of Staphylococcus aureus, coagulase-negative (CN) staphylococci, Listeria monocytogenes, Escherichia coli, Enterococcus faecalis, E. faecium and Bacillus cereus, was investigated in 111 bulk milk samples. Staphylococcus aureus was isolated from 38 samples, CN staphylococci from 63 samples, E. coli from 49 samples, E. faecalis or E. faecium from 107 samples, and L. monocytogenes from two samples. Bacillus cereus was not found in any of the samples and three samples were free of any of the selected species. Sensitivity to the anti-microbial drugs amikacin, ampicillin, ampicillin + sulbactam, cephalothin (CLT), cephotaxime, clindamycin, chloramphenicol (CMP), co-trimoxazole, erythromycin (ERY), gentamicin, neomycin, norfloxacin, oxacillin, penicillin, streptomycin (STR), tetracycline (TTC) and vancomycin was tested using the standard dilution technique. Minimum inhibitory concentration (MIC) characteristics (MIC50, MIC90, MIC range) were determined for each microbial species. Resistance against one or more anti-microbial drugs was found in 93% of S. aureus, 40% of CN staphylococci, 73% of E. coli, 88% of E.faecalis, 55% of E.faecium, and one L. monocytogenes strain. Most of the strains, particularly enterococci, were resistant to STR, TTC, and ERY (MIC50 4 microg/ml). A high percentage of staphylococci were resistant to beta-lactam antibiotics. High resistance to CLT was found in 11 strains of E. coli (MIC 256 microg/ml) and strains resistant to CMP (MIC90 16 microg/ml) were detected. The highest numbers of resistance phenotypes were found in E. coil (16) and CN staphylococci (12). Eighteen identical resistance phenotypes were demonstrated in indicator bacteria (E. coli, E. faecalis, E. faecium) and pathogens (S. aureus, CN staphylococci) isolated from the same bulk milk sample. The obtained resistance data were matched against the herd owners' information on therapeutic use of the drugs. This confrontation could not explain the findings of strains resistant to ERY or CMP. Our findings are evidence of selection of resistant strains among not only pathogenic agents, but also among indicator bacteria which can become significant carriers of transmissible resistance genes.     

西安市售乳制品中抗菌药的残留检测

为了解西安市售消毒乳制品中抗菌药残留情况,以农业部2001年发布的无公害食品行业标准中牛乳不得检出抗菌药为判定标准,随机采购32份消毒牛奶,进行抗菌药残留检测。TTC法检测显示,抗菌药物残留阳性数为5份,阳性率为15.63%;ELISA法检测显示,磺胺二甲基嘧啶未检出,四环素类残留阳性数为3份,阳性率为9.38%,链霉素残留阳性数为7份,阳性率为21.88%。市售不同包装消毒牛奶中除新鲜屋包装外,其余均有抗菌药残留。进口消毒奶粉未检出抗菌药,检测国产消毒牛奶32份与国产奶粉20份,共检出阳性10份与11份,阳性率分别为31.25%和55%。通过检测可看出,奶粉中抗菌药残留阳性率显著比消毒牛奶高;包装精良的高档牛奶中抗菌药残留阳性率比普通包装牛奶低;进口消毒奶粉未检出抗菌药。检测结果显示抗菌药残留情况仍不容乐观。     

乳与乳制品快速检测抗生素残留方法的研究

随机于市场抽样乳及乳制品80件，分别用微生物抑制法（ECLIPSE100试剂盒法）和国标TFC法进行检测，比较两种方法检测食品中抗生素残留的符合性。结果显示，两种检测方法检测乳及乳制品中抗生素残留结果有显著性差异。相比较TFC的精确度较低且适用检测范围也较低，假阴性率较高，而微生物抑制法同时可检测30多种药物残留，且检测精度均符合欧洲标准评判的要求。     

奶牛乳房炎大肠杆菌刃天青微量板快速诊断及药敏试验

为了建立奶牛乳房炎大肠杆菌快速诊断与药敏试验方法,用刃天青钠取代大肠杆菌选择培养基MQQ中的酚红指示剂,通过对刃天青的工作浓度、大肠杆菌接种量和培养时间等参数的研究,建立了奶牛乳房炎大肠杆菌刃天青微量板快速诊断方法.将不同细菌及其感染模拟奶样进行刃天青微量板快速培养结果显示,此刃天青微量板对大肠杆菌具有很强的选择培养特性,能在10 h内获得明确诊断结果,并能反映奶牛乳腺大肠杆菌感染强度.对89份临床奶样进行大肠杆菌刃天青微量板快速诊断敏感性和特异性检测,结果显示,此刃天青微量板法诊断大肠杆菌阳性奶样敏感性高达100%,诊断大肠杆菌阴性奶样特异性高达94.9%,总符合率高达95.5%.在此基础上用矫正浓度10种抗生素包被微量板,分别用10株大肠杆菌纯培养菌株及其感染模拟奶样和10份大肠杆菌阳性奶样进行快速药敏试验,所获结果与标准纸片扩散法完全一致.这些研究结果表明,本研究建立的刃天青微量板法可以取代常规方法用于奶样大肠杆菌的快速诊断及药敏试验.     

A Resazurin Microplate Assay for Quick Diagnosis and Antibiotic Sensitivity Measurement of Bovine Mastitis-causing E.coli

To establish a microplate assay for quick diagnosis and antibiotic sensitivity measurement of bovine mastitis-causing E.coli,the phenol red indicator in E.coli selective medium was replaced with resazurin and the resazurin microplate assay was established by determing of optimization of indicator concentration,bacterial inoculation dose and culture time.The testing results of different bacteria and their infection-mimicking milk samples showed that the microplate assay had a strong selective property for E.coli and the definite diagnostic result could be obtained within 10 h with a capability of reflecting infection strength of dairy cow mammary gland.The results of 89 mastitis-positive milk samples showed that the microplate assay had a detection sensitivity of 100%,and the negative milk samples specificity was 94.9%,95.5% agreement to the conventional culture-based method.The micoplates were coated with rectified concentrations of 10 different antibiotics and the quick drug sensitivity assay was performed using 10 E.coli strains,infection-mimicking milk samples and 10 E.coli-positive milk samples.The obtained results had a complete agreement with that of standard disc diffusion method.These data suggested that the resazurin microplate assay established in this study could replace the conventional methods for quick diagnosis and antibiotic sensitivity measurement of bovine mastitis-causing E.coli.     

Prevalence of and Resistance to Anti‐Microbial Drugs in Selected Microbial Species Isolated from Bulk Milk Samples

The prevalence of strains of Staphylococcus aureus, coagulase‐negative (CN) staphylococci, Listeria monocytogenes, Escherichia coli, Enterococcus faecalis, E. faecium and Bacillus cereus, was investigated in 111 bulk milk samples. Staphylococcus aureus was isolated from 38 samples, CN staphylococci from 63 samples, E. coli from 49 samples, E. faecalis or E. faecium from 107 samples, and L. monocytogenes from two samples. Bacillus cereus was not found in any of the samples and three samples were free of any of the selected species. Sensitivity to the anti‐microbial drugs amikacin, ampicillin, ampicillin + sulbactam, cephalothin (CLT), cephotaxime, clindamycin, chloramphenicol (CMP), co‐trimoxazole, erythromycin (ERY), gentamicin, neomycin, norfloxacin, oxacillin, penicillin, streptomycin (STR), tetracycline (TTC) and vancomycin was tested using the standard dilution technique. Minimum inhibitory concentration (MIC) characteristics (MIC₅₀, MIC₉₀, MIC range) were determined for each microbial species. Resistance against one or more anti‐microbial drugs was found in 93% of S. aureus, 40% of CN staphylococci, 73% of E. coli, 88% of E. faecalis, 55% of E. faecium, and one L. monocytogenes strain. Most of the strains, particularly enterococci, were resistant to STR, TTC, and ERY (MIC₅₀ 4 μg/ml). A high percentage of staphylococci were resistant to β‐lactam antibiotics. High resistance to CLT was found in 11 strains of E. coli (MIC 256 μg/ml) and strains resistant to CMP (MIC₉₀ 16 μg/ml) were detected. The highest numbers of resistance phenotypes were found in E. coli (16) and CN staphylococci (12). Eighteen identical resistance phenotypes were demonstrated in indicator bacteria (E. coli, E. faecalis, E. faecium) and pathogens (S. aureus, CN staphylococci) isolated from the same bulk milk sample. The obtained resistance data were matched against the herd owners' information on therapeutic use of the drugs. This confrontation could not explain the findings of strains resistant to ERY or CMP. Our findings are evidence of selection of resistant strains among not only pathogenic agents, but also among indicator bacteria which can become significant carriers of transmissible resistance genes.     

Infectious aetiologies of mastitis on Korean dairy farms during 2008

The objective of this study was to determine the frequency of different mastitis pathogens in 1255 milk samples collected from 368 lactating cows on 24 dairy farms in Korea during 2008. The proportion of cows and quarter milk samples having SCC ? 200,000 cells/ml, an indicator of udder infection, was 54.3% (200/368 cows) and 35.5% (446/1255 samples), respectively. Of the 446 milk samples subjected to bacteriological examination, 16.5% (74) showed no bacterial growth and 3.5% (16) were contaminated. In total, 356 of 1255 (28.3%) samples were bacteriologically positive, from which 415 bacteria were isolated. The most frequently isolated pathogen was coagulase-negative staphylococci (40.7%), followed by Gram-negative bacteria (19.5%) other than Escherichia coli, Staphylococcus aureus (12.2%), Streptococcus uberis (5.3%), Enterococcus spp. (4.8%), E. coli (4.5%), and environmental streptococci (3.1%) other than S. uberis. This study demonstrates that environmental pathogens were the vast majority of bacteria isolated from mastitic bovine milk samples in Korea.