低聚糖硫酸酯及右旋糖酐硫酸酯对临床型奶牛乳房炎治疗效果的研究

为探究低聚糖硫酸酯（DEAE）及右旋糖酐硫酸酯（DS-4000）对临床型奶牛乳房炎的治疗效果,将56头患临床型乳房炎奶牛随机分为5组（DEAE组、DS-4000组、DEAE＋青霉素组、DS-4000＋青霉素组及青霉素对照组）,进行药物乳房灌注治疗,每天2次,连用3 d,并在治疗前后分别采集奶样进行细菌学检测。临床观察统计各治疗组有效率,细菌检测统计细菌转阴率。结果显示,奶牛乳房灌注DEAE、DS-4000、DEAE＋青霉素、DS-4000＋青霉素及青霉素进行治疗3 d后,总有效率分别为：10.00%、20.00%、58.33%、75.00%和50.00%;乳汁细菌转阴率分别为：0、12.50%、50.00%、54.55%和44.44%。结果表明,DEAE及DS-4000对临床型奶牛乳房炎有一定的治疗作用,但效果不理想,与青霉素联用可以增强抗生素的疗效。     

Efficacy of specific egg yolk immunoglobulin (IgY) to bovine mastitis caused by Staphylococcus aureus

The objective of this study was to estimate the efficacy of specific egg yolk immunoglobulin (IgY) to bovine mastitis caused by Staphylococcus aureus. Eighteen lactating cows with clinical mastitis and 18 lactating cows with experimental mastitis (1 quarter per cow) were randomly assigned to three treatments: IgY (20mg/ml) infusion, penicillin (100mg/ml) infusion and no infusion. Treatments for clinical mastitis and experimental mastitis were performed by a 6-day course of intramammary infusion with a dosage of 10ml at an interval of 12h. Milk samples were collected at morning milking time for testing color, clot, somatic cell counts (SCC) and bacterial count. For most of the cows treated with IgY and penicillin, the milk color and clot recovered to normal form during the therapy course. The milk SCCs and bacterial counts of treated cows decreased compared to those of untreated cows (p<0.05). The cure rates by IgY for experimental and clinical mastitis were 83.3% and 50%, respectively, and those by penicillin were 66.7% and 33.3%, respectively. These results showed the potential of specific IgY to be an alternative therapy for mastitis caused by S. aureus.     

Intramuscular treatment of subclinical staphylococcal mastitis in lactating cows with penicillin G, methicillin and their esters

The relationship between antibiotic milk concentrations and bacteriological efficacy was investigated in groups of lactating cows with subclinical mastitis due to either penicillin G-sensitive or penicillin G-resistant Staphylococcus aureus. Treatments consisted of the intramuscular injection of procaine penicillin G, or its weak base ester penethamate hydriodide, and sodium methicillin, or its weak base ester tamethicillin. Antibiotics were administered once daily for 2 or 4 days at accepted dosages. After four daily, treatments with procaine penicillin G and penethamate hydriodide, infections were eliminated from 56.5% and 68.8%, respectively, of quarters infected with penicillin G-sensitive staphylococci, and from 14.3% and 7.7%, respectively, of quarters infected with penicillin G-resistant staphylococci. After four daily treatments with sodium methicillin and tamethicillin, infections were eliminated from 32.4% and 48.6%, respectively, of quarters infected with penicillin G-resistant staphylococci. The better efficacy of penethamate hydriodide and tamethicillin was considered to be linked to the higher milk drug concentrations obtained with these drugs as opposed to the lower concentrations measured in the milk after treatment with the parent drugs. Cure rates were generally higher after treatment for 4 days than after the 2-day course of therapy. Treatment efficacy decreased progressively with increasing age of the cows. Intramuscular treatment of subclinical staphylococcal mastitis in lactating cows can serve as a useful model for screening existing and new antibacterial agents and drug products intended for the parenteral treatment of clinical staphylococcal mastitis.     

Antimicrobial resistance patterns to beta-lactams of gram-positive cocci isolated from bovine mastitis in Lithuania

The aim of the study was to isolate gram-positive cocci from cows with mastitis and to determine their resistance to beta-lactamic antibiotics. Eight hundred and nine strains were isolated and identified as staphylococci (n=516), streptococci (n=199) and enterococci (n=94) from sub-clinical and clinical cases of bovine mastitis in Lithuania. The most common causative agents of udder disease included: S. epidermidis (n=176), S. aureus (n=176), S. agalactiae (n=134), S. hyicus (136) and E. hirae (n=68). Isolates were analysed for antimicrobial resistance to penicillin, ampicillin, amoxicillin, cephalothin, cephalexin, amoxicillin + clavulanate. The susceptibility patterns were analysed using the agar disk diffusion method. S. aureus showed the highest level of resistance to amoxicillin (81.3%), penicillin (76.7%) and ampicillin (78.4%). The corresponding values for CNS strains were 59.7%, 59.7% and 50.6% against penicillin, ampicillin and amoxicillin respectively. Streptococci were the most frequently resistant to amoxicillin (29.3%), and enterococci to penicillin (27%), amoxicillin (27.5%) and amoxicillin/clavulanic acid (23.8%). The resistance of all tested mastitis pathogens to aminopenicillins and penicillin highly correlated (r=0.83). Compared with other antibiotics, amoxicillin and clavulanic acid combination tended to be more effective (p<0.05) against all tested bacteria in vitro. However, S. aureus, in 38.1% of cases, was resistant to this combination of antimicrobials. This study demonstrates that S. epidermidis, S. aureus, S. hyicus, S. agalactiae and E. hirae remain the most frequent mastitis causative agents on Lithuanian cattle farms. The highest resistance in vitro to penicillins was demonstrated by S. aureus, S. hyicus and S. intermedius. Resistance to cephalosporins remains low, irrespective of bacterial species of gram-positive cocci.     

复方阿莫西林乳房注入剂对临床型奶牛乳房炎的治疗效果

为评价复方阿莫西林乳房注入剂对泌乳期奶牛临床型乳房炎的治疗效果,在甘肃某两个牛场选择70头自然发生的临床型乳房炎奶牛进行临床试验。将患病奶牛随机分为试验组(n=36头)和对照组(n=34头)。试验用药和对照用药分别为郑州百瑞动物药业有限公司和齐鲁动物保健品有限公司提供的复方阿莫西林乳房注入剂。每个感染乳区注入3 g药物,每12 h注射1次,连续用药3 d。在用药前、停药后7 d及14 d采集各组奶牛的奶样进行细菌学检测及乳汁体细胞计数。通过临床观察、细菌清除率及体细胞计数变化对临床疗效进行评价。停药后14 d,试验组和对照组的临床治愈率分别为58.3%和61.8%,细菌总清除率分别为94.12%和93.55%。两组奶样中的SCC在治疗后均显著下降(P<0.01)。两组临床疗效无统计学差异(P>0.05),表明试验用药对奶牛临床型乳房炎具有良好的治疗效果。     

奶牛临床型乳腺炎致病菌分离鉴定及2种常见用药方案的疗效研究

为了研究奶牛乳腺炎致病菌种类,同时比较青霉素、链霉素合并使用与沃瑞特单独使用在奶牛临床型乳腺炎的治疗中的疗效差异,以100头患有临床型乳腺炎的奶牛为研究对象,对从乳样中分离到的细菌进行鉴定;在同一饲养管理条件下将上述患牛分为对照组（4头）、沃瑞特组（50头）、青链霉素组（46头）进行疗效对比研究。结果表明,致病菌葡萄球菌的分离率为37.0%、大肠杆菌为30.1%、克雷伯菌为 18.3%、链球菌为2.4%,其他菌为12.2%,占比例最高的是葡萄球菌;2种用药方案均收到良好的治疗效果,青链霉素组治愈率为78.26%,沃瑞特治愈率为66.00%,青链霉素组治愈率显著高于沃瑞特组。     

重组溶葡萄球菌酶对奶牛乳房炎的疗效研究

以85头患乳房炎奶牛共104个乳区为研究对象,随机分为4组,每组26个,分别用重组溶葡萄球菌酶粉低（200U／乳区）、中（400U／乳区）、高（800U／乳区）三个剂量,对照组为青霉素G钠（160万IU／乳区）,每天早晚挤奶后乳池灌注给药,共4d,研究不同剂量重组溶葡萄球菌酶对奶牛乳房炎的治疗效果。试验结果显示,低、中、高剂量重组溶葡萄球菌酶均能有效清除感染乳区的链球菌、葡萄球菌、化脓隐秘杆菌等G^＋菌,大幅降低牛奶中的白细胞数,提高日产奶量。其中低剂量组对隐性乳房炎、临床型乳房炎的有效率和治愈率略优于青霉素G钠（P〉0．05）;中、高剂量对隐性乳房炎、临床型乳房炎的有效率和治愈率显著优于青霉素G钠（P〈0．05）;中、高剂量的疗效相当（P〉0．05）。重组溶葡萄球菌酶是一种很好的治疗奶牛隐性乳房炎和临床乳房炎备选药物。     

Efficacy of targeted 5-day combined parenteral and intramammary treatment of clinical mastitis caused by penicillin-susceptible or penicillin-resistant Staphylococcus aureus

Combined parenteral and intramammary treatment of mastitis caused by Staphylococcus aureus was compared to parenteral treatment only. Cows with clinical mastitis (166 mastitic quarters) caused by S. aureus treated by veterinarians of the Ambulatory Clinic of the Faculty of Veterinary Medicine during routine farm calls were included. Treatment was based on in vitro susceptibility testing of the bacterial isolate. Procaine penicillin G (86 cases due to beta-lactamase negative strains) or amoxycillin-clavulanic acid (24 cases due to beta-lactamase positive strains) was administered parenterally and intramammarily for 5 days. Efficacy of treatments was assessed 2 and 4 weeks later by physical examination, bacteriological culture, determination of CMT, somatic cell count and NAGase activity in milk. Quarters with growth of S. aureus in at least one post-treatment sample were classified as non-cured. As controls we used 41 clinical mastitis cases caused by penicillin-susceptible S. aureus isolates treated with procaine penicillin G parenterally for 5 days and 15 cases due to penicillin-resistant isolates treated with spiramycin parenterally for 5 days from the same practice area. Bacteriological cure rate after the combination treatment was 75.6% for quarters infected with penicillin-susceptible S. aureus isolates, and 29.2% for quarters infected with penicillin-resistant isolates. Cure rate for quarters treated only parenterally with procaine penicillin G was 56.1% and that for quarters treated with spiramycin 33.3%. The difference in cure rates between mastitis due to penicillin-susceptible and penicillin-resistant S. aureus was highly significant. Combined treatment was superior over systemic treatment only in the beta-lactamase negative group.     

Lactoferrin against Staphylococcus aureus Mastitis. Lactoferrin alone or in combination with penicillin G on bovine polymorphonuclear function and mammary epithelial cells colonisation by Staphylococcus aureus

Antibiotics should combine good antibacterial activity and the capacity to work in association with the host defence system. In this study, we have investigated the effects of bovine lactoferrin alone or in combination with penicillin G on the phagocytic activity of bovine polymorphonuclear leukocytes against Staphylococcus aureus. We have shown that susceptibility of S. aureus to phagocytosis was decreased in the presence of penicillin in the medium. In a kinetic study, lactoferrin alone did not affect phagocytosis but, when used with penicillin, it reversed the negative effect of this antibiotic on phagocytosis. In addition, in an epithelial invasion assay, lactoferrin alone or in combination with penicillin reduced the invasion of mammary epithelial cells in culture by S. aureus. Lactating female CD-1 mice were infected by intra-mammary delivery of a virulent penicillin-susceptible S. aureus strain and were then randomly assigned to treatments according to a 2 x 2 factorial design. In this mouse mastitis model, 2 days of systemic treatments with lactoferrin and/or penicillin did not lead to a total clearance of infection by S. aureus, but bacterial number was significantly reduced by treatments with lactoferrin or penicillin. These data suggest that bovine lactoferrin, alone or in combination with penicillin G, enhances S. aureus susceptibility to immuno-defense mechanisms, which can be beneficial in the treatment of S. aureus infections.     

Association between phage types and antimicrobial resistance among bovine Staphylococcus aureus from 10 countries

This study was conducted to investigate the diversity of phage types and associations between penicillin resistance and phage types among 815 Staphylococcus aureus isolates from bovine mastitis in nine European countries and USA. All isolates were examined for susceptibility to antimicrobial agents and characterised by phage typing. Penicillin resistance was found among strains from all countries with an average occurrence of 32.4% (2-71.4%). A total of 76% of isolates were identifiable by phage typing and 144 different phage types were observed. The most predominant types were phage type 29 (11% of the 815 isolates), phage type 52 (5%), and phage type 80 (5%). Phage type 95 and 29/52/52A/80 were both distributed within seven countries. In the countries with the highest occurrence of penicillin resistance a reduced diversity of phage types and phage groups was observed. Phage group III was significantly associated with penicillin resistance in contrast to phage group I (P=0.0023) and phage complex-80 (P=0.0066). This study confirms that a large number of phage types of S. aureus cause bovine mastitis, but that some types predominate. In addition, these findings could indicate that the use of penicillin in the bovine environment has selected for specific types of S. aureus in countries with a high frequency of resistance.     

Efficacy of intramammary treatment with procaine penicillin G vs. procaine penicillin G plus neomycin in bovine clinical mastitis caused by penicillin-susceptible,gram-positive bacteria--a double blind field study

The efficacy of intramammary treatments containing procaine penicillin G alone (treatment A) or a combination of procaine penicillin G and neomycin (treatment B) was compared in treating clinical bovine mastitis caused by gram-positive bacteria susceptible in vitro to penicillin G. Both treatments were supplemented with a single intramuscular injection of procaine penicillin G on the first day of treatment. The study was carried out using a double blind design on commercial dairy farms in Southern Finland. A total of 56 quarters were treated with treatment A and 61 with treatment B. The cure rates for both treatments were equal, which suggests that the use of the penicillin G-aminoglycoside combination does not increase the efficacy of the treatment over that achieved by using penicillin G alone in bovine clinical mastitis caused by penicillin-susceptible, gram-positive bacteria.     

氦氖激光治疗奶牛乳房炎试验报告

在应用HMT试液诊断的139头奶牛中,选择乳房炎阳性反应奶牛123头,418个乳区(含临床型和亚临床型乳区8个),分为8mw激光照射组、18mw激光照射组、青霉素乳头注入对照组和不治疗对照组进行试验。激光照射组全用原光束,距离30～40cm,时间分别为8min和10min,照射乳中穴,每天一次,共照射七天。在激光照射疗效方面,以8mw组为最高,对各型乳房炎乳区治愈率为85.81％,好转率为11.49％,总有效率为97.3％;对隐性型乳区治愈率为90.7％,好转率为8.6％,总有效率为99.3％;药物对照组对隐性型治愈率为28.13％,好转率为25％,总有效率为53.13％;不治疗对照组试前乳区阳性率为73.6％,试后乳区阳性率为78.02％,自然发病增长率为4.42％。试验中还测定了各种处理对产奶量的影响,结果表明,以18mw组为最好,平均每日每头增加1.6318kg,药物对照组和不治疗对照组平均每日每头分别减少0.3989kg和0.581kg,经统计处理,激光照射组与对照组之间差异极为显著。     

Antimicrobial susceptibility of bacterial isolates from 233 horses with musculoskeletal infection during 1979-1989.

Bacterial culture and susceptibility results were analysed from 233 horses with septic arthritis/tenosynovitis or osteomyelitis that developed after fracture repair. Antibiotics were deemed highly effective, effective or ineffective if > or = 85%, 70-84.9% or < 70% of the isolates were susceptible respectively. In total, 424 bacterial types were isolated; 386 were aerobic or facultative and 38 were anaerobic. Enterobacteriaceae (28.8%) were the most common bacterial group isolated, followed by non-beta-haemolytic streptococci (13.0%), coagulase-positive staphylococci (11.8%), beta-haemolytic streptococci (9.4%), and coagulase-negative staphylococci (7.3%). The remainder of the organisms were other Gram-negative (15.8%), other Gram-positive (2.3%) and miscellaneous (2.6%) bacteria. Penicillin and ampicillin were highly effective against beta-haemolytic streptococci, but were ineffective against other bacteria. Ampicillin was no more effective than penicillin against most bacteria. Amikacin was the most effective antibiotic against the wide range of bacteria isolated in this study. Amikacin was highly effective against coagulase-positive staphylococci, Enterobacteriaceae and Pseudomonas and was effective against coagulase-negative staphylococci and Actinobacillus. Gentamycin was not highly effective against any bacterial group; but was effective against coagulase-positive and negative staphylococci, Pseudomonas, Salmonella and Actinobacillus. Kanamycin was ineffective against all bacteria with the exception of Actinobacillus. Cephalothin was highly effective against beta-haemolytic streptococci, coagulase-positive staphylococci and Actinobacillus and was effective against coagulase-negative staphylococci.(ABSTRACT TRUNCATED AT 250 WORDS)     

Therapeutic effects of systemic or intramammary antimicrobial treatment of bovine subclinical mastitis during lactation

The short- and long-term treatment efficacy of administrating penicillin for bovine subclinical mastitis during lactation when using intramuscular (IM; 9.5 mg [15,000 IU]/kg bodyweight of benzyl penicillin potassium) injections twice daily for 5 days, or intramammary (IMM; 0.3g [300,000 IU] penethamate hydroiodide) administration once daily for 5 days was compared with a control group receiving no treatment. One hundred and twenty-six cows met the inclusion criteria, which were lack of clinical symptoms, no recent treatment with antimicrobials, and findings of penicillin-sensitive Staphylococcus aureus, Streptococcus dysgalactiae, or Streptococcus uberis in combination with an inflammatory reaction. At follow-up 42-58 days after treatment, the proportion of cows negative for the original infection was significantly higher in IM and IMM groups compared to controls, but the difference between antimicrobial treatment groups was not significant. The udder quarter milk somatic cell count (SCC) was significantly lower at follow-up in IM and IMM groups than in controls, but milk production did not differ between treatments. The culling rate during the 10-month period following treatment was significantly higher in the group treated with IMM penicillin than in the other two groups, but the risk of new mastitis treatments within 10 months did not differ between the three groups. The cure rate was significantly affected by lactation number (lower in older cows), breed (lower in the Swedish Holstein breed), pathogen (lower for S. aureus), and pre-treatment SCC (higher for above average SCC). In conclusion, beneficial long-term effects of antimicrobial treatment during lactation of subclinical mastitis caused by S. aureus, Str. dysgalactiae or Str. uberis were not found in the present study.     

利福昔明对奶牛乳房炎常见病原菌的体外抗菌活性试验

旨在测定利福昔明对奶牛乳房炎常见病原菌的体外抗菌活性。采用琼脂二倍稀释法测定利福昔明对奶牛乳房炎常见病原菌大肠杆菌、葡萄球菌和链球菌的最小抑菌浓度（MIC）。结果显示,利福昔明对19株大肠杆菌的MIC值为8~16μg/m L,对25株葡萄球菌的MIC值为0.002~0.06μg/m L,对18株链球菌的MIC值为0.06~2μg/m L。大部分临床分离菌的MIC值与标准菌的相近,表明分离菌株对利福昔明较为敏感,提示利福昔明对奶牛乳房炎常见病原菌具有较强的体外抗菌活性。     

Italian University System has to Match Educational Needs in Adherence to European Standards and Professional Scenario

The effect of a water-soluble fraction (WSF) of a non-pathogenic strain of Mycobacterium phlei was studied in bovine subclinical mastitis (SCM) by measuring the myeloperoxidase and acid phosphatase enzyme levels in the milk leukocytes. Forty-five cows were divided into three equal groups. Group I, consisting of 15 healthy cows, served as the control, whereas groups II and III each contained 15 cows with subclinical mastitis on the basis of a positive reaction in the California mastitis test (CMT). The cows in group II received 100 microg of WSF in 5 ml sterile phosphate-buffered saline, pH 7.4 (PBS) once only, while those in group III received 5 ml sterile PBS daily for 7 days, both treatments being given by the intramammary route. Observations were made up to 30 days after treatment (AT). The CMT of the healthy milk was negative (0), whereas it ranged between 1 and 2 points in SCM. The somatic cell count (SCC) increased significantly (p < 0.05) on day 3, then fell steeply from day 7 up to day 30 AT in the cows in group II. A steady decrease in the total bacterial count (TBC) was observed in the group treated with WSF but the bacterial counts remained high in the groups treated with PBS. The mean acid phosphatase level was enhanced by 119% on day 3 AT in group II but only by 18.7% in the cows in group III. The mean myeloperoxidase level was enhanced by 100% in the cows in group II but only by 18% in those in group III on day 3 AT. This significant reduction in the bacterial load in infected cows caused by intramammary infusion of WSF may be due to activation of the microbicidal activity of the neutrophils, but this requires confirmation.     

乳酸链球菌素治疗奶牛乳房炎效果观察

乳酸链球菌素（Nisin）是由乳酸链球菌产生的合有34个氨基酸的抗菌肽,对人体无害。本研究将患临床型乳房炎奶牛92头（107个乳区）和隐性乳房炎奶牛90头（90个乳区）随机分成试验组和对照组。试验组的治疗方法是在患病乳区灌注Nisin;临床型乳房炎以庆大霉素乳房内灌注作对照,隐性乳房炎的对照组不作任何处理。临床型乳房炎的Nisin治疗组细菌学治愈率和临床治愈率分别为60．8％和90．2％,而庆大霉素治疗组则分别为44.6％和91．2％,两者无统计学差异。隐性乳房炎经Nisin治疗后,高体细胞数奶牛的数量和牛奶中NAGase的活性均显著下降,细菌转阴率提高。乳酸菌发酵试验表明,经Nisin乳房内灌注治疗临床型乳房炎后,牛奶在第36小时恢复正常发酵,而庆大霉素治疗则需要72h。     

云南地区牛源无乳链球菌分离鉴定及毒力基因和耐药性的检测

试验旨在研究无乳链球菌的生物学特性,为防治无乳链球菌引起的奶牛乳房炎提供理论依据。根据细菌分子生物学分离鉴定无乳链球菌,参考GenBank登录的牛源无乳链球菌16S rRNA、菌属特异性cfb （CAMP因子）、毒力基因和耐药基因序列,运用Oligo 6.0和Primer Premier 5.0软件设计14对引物,建立PCR快速检测方法,并进行20种常见抗生药物的耐药试验。结果显示,试验成功鉴定出17株牛源无乳链球菌,毒力基因与NCBI上已报道的无乳链球菌相应序列具有高度同源性,均≥99%;共检测到6种耐药基因;分离菌株对青霉素、红霉素、林可霉素、克林霉素、万古霉素、氨苄西林、新生霉素、磺胺异噁唑的耐药率均较高,耐药率依次为100.0%、94.1%、94.1%、94.1%、94.1%、82.3%、82.3%和47.1%,对青霉素严重耐药;而对氨基糖苷类、四环素类、头孢菌素类、喹诺酮类耐药率均较低,耐药率分别为15.7%、14.7%、7.7%和3.9%。本研究结果表明,建立的PCR快速检测方法灵敏可靠,云南地区无乳链球菌已对部分β-内酰胺类、大环内酯类、磺胺类等抗生素出现多重耐药性。     

冀东地区奶牛隐性乳房炎病原菌的分离鉴定

通过LMT法、乳汁pH检验法和体细胞直接计数等方法相结合,对冀东地区3个大型奶牛场、8个奶牛养殖户选取的1 021头奶牛进行隐性乳房炎流行病学调查与病菌分离鉴定。结果表明,隐性乳房炎发病率为60.63%(619/1021),乳房炎阳性乳样品中细菌分离率达88.21%(546/619)。从543头隐性乳房炎患牛的阳性乳区乳样中分得细菌共4类14种菌82株,其中葡萄球菌36株,占43.90%;链球菌33株,占40.24%;肠杆菌类8株,占9.76%;棒状杆菌5株,占6.10%。冀东地区奶牛隐性乳房炎主要病原菌为金黄色葡萄球菌和无乳链球菌。     

重组溶菌酶质粒pcDNAKLYZ治疗泌乳期奶牛乳房炎

通过比较注射人溶菌酶重组质粒pcDNAKLYZ的隐性乳房炎奶牛注射前后的奶样中细菌计数结果,对重组溶菌酶基因工程质粒治疗奶牛乳房炎的效果进行分析。对乳房炎患牛的156个乳区治疗前后312份奶样进行细菌培养,其中在注射前的乳样的培养结果中,阴性率为0（0/156）,菌落数在50以内的比率为12.82%（20/156）,在51～100的比率为16.67%（26/156）,大于等于100的比率为70.51%（110/150）;在注射人溶菌酶的重组质粒pcDNAKLYZ后的奶牛乳样的培养结果中,阴性率为51.92%（81/156）,菌落数在50以内的比率为45.51%（71/156）,菌落数在51～100的比率为0%（0/156）,大于等于100的比率为2.56%（4/156）。因此,从细菌计数结果来看,重组质粒组的阴性及小于50的比率（97.44%）远高于治疗前（12.82%）,重组质粒的抑菌效果显著（P〈0.05）,该重组质粒对奶牛乳房炎具有较好的治疗效果。