In vitro and in vivo evaluation of a 0.5% chlorhexidine gluconate teat dip

The activity of a 0.5% chlorhexidine gluconate postmilking teat germicide in reducing the numbers of Staphylococcus aureus and Streptococcus agalactiae on the skin of excised teats from cows was determined. The product yielded logarithmic reductions of 4.09 and 4.10 against S aureus and Str agalactiae, respectively, compared with 3.80 and 3.81 reductions, using a 1% iodophor dip. Germicide tolerance to an organic load containing Serratia marcescens or Pseudomonas spp was also determined. Organisms were not recovered from the product 8 hours after introduction of a simulated organic load containing either species of bacteria. The germicide was further evaluated against S aureus and Str agalactiae, using experimental challenge-exposure procedures in a research dairy herd. Efficacy was 73.4% (P less than 0.001) against S aureus and 68.1% (P less than 0.005) against Str agalactiae.     

Effect of premilking teat disinfection on mastitis incidence, total bacterial count, cell count and milk yield in three dairy herds.

An iodophor teat disinfectant was applied before milking by dip or spray to 50 cows and 50 cows were left untreated in each of three commercial herds. The mean incidence of clinical mastitis was reduced by 57 per cent, the total bacterial count by 70 per cent and the count of thermoduric organisms by 32 per cent. These results were not statistically significant, except that one herd showed a significant decrease in total bacterial count. There was no effect on somatic cell count, milk production or milk iodine residues. Atmospheric iodine concentrations increased in the two herds which applied the treatment as a spray, but the levels attained were not likely to be detrimental to human health.     

Efficacy of a germicidal post milking barrier-type teat dip in preventing intramammary infections

Five commercial dairy herds with 269 lactating cows participated for 12 months in a field trial to determine the effectiveness of a barrier teat dip containing chlorous acid/chlorine dioxide germicide. The right quarters of the cows in two herds and the left quarters of the cows in three herds were dipped in the experimental teat dip after the removal of the milking machine. The other quarters were dipped in a conventional 0.5 per cent iodophor product. Compared with this control product, teat dipping with the experimental dip reduced the number of new intramammary infections by 18.8 per cent, infections with major pathogens by 13.6 per cent, infections with minor pathogens by 16.8 per cent and clinical mastitis by 33.3 per cent. Statistical analysis indicated a trend towards decreased intramammary infections with coliforms and coagulase-negative staphylococci when the experimental teat dip was used. It was concluded that under the conditions of this investigation it was effective in preventing new infections due to both contagious and some environmental pathogens. However, the data suggested that it could adversely affect the condition of the skin of the teat when it was used after incorrect preparation of the udder.     

Chlorhexidine Diacetate and Povidone-iodine Cytotoxicity to Canine Embryonic Fibroblasts and Staphylococcus aureus

Chlorhexidine diacetate and povidone-iodine were evaluated for fibroblast toxicity on a primary line of canine embryonic fibroblasts, and for bactericidal efficacy against Staphylococcus aureus. The cultured fibroblasts or S. aureus were exposed for 30 minutes to incremental dilutions of 0.5 and 0.0005% chlorhexidine diacetate, 5.0 to 0.05% povidone-iodine, or physiologic buffered saline as a control. To determine survival, fibroblasts were trypsinized and counted; S. aureus colonies were counted on brain-heart infusion agar. Survival for both groups was expressed by calculating the number of living cells in test dilutions as a percentage of the number in control cultures. Fibroblast survival occurred at chlorhexidine concentrations less than 0.013% and at povidone-iodine concentrations less than 0.5% (p less than 0.05). Significant S. aureus survival (p less than 0.05) was noted at chlorhexidine concentrations less than 0.05% and povidone-iodine concentrations less than 1.0%. These data showed that all bactericidal concentrations of chlorhexidine diacetate and povidone-iodine were lethal to canine embryonic fibroblasts in vitro, whereas non-lethal concentrations allowed significant bacterial survival.     

奶牛纯中药乳头消毒剂的临床应用效果观察

将93头奶牛分成3组,1组31头用碘伏进行乳头药浴,2 组 32 头用鱼腥草、红花和明矾组成的中药乳头消毒剂进行药浴,30 头作为对照组,35 d的临床应用,结果如下:中药乳头消毒剂和碘伏能使临床型乳腺炎发病率降低,差异不显著(P>0 05);1组隐性乳腺炎的发病率,由药浴前的 58 1%下降到 48 4%,与对照组差异显著(P<0 05),2组隐性乳腺炎的发病率由药浴前的81 3%下降到药浴后的75%,与对照组差异显著(P>0 05);1 组和2组隐性乳腺炎的乳区发病率差异不显著(P>0 05),与对照组差异极显著(P<0 01);中药乳头消毒剂药浴后体细胞数和LDH活性明显降低,与药浴前差异显著(P<0 05);NAGase的活性药浴前后差异不显著(P>0 05),该中药乳头消毒剂对奶产量无显著影响。     

Effects of Chlorhexidine Gluconate and Chlorous Acid-Chlorine Dioxide on Equine Fibroblasts and Staphylococcus aureus

Equine fibroblasts and Staphylococcus aureus were exposed for 30 minutes to six dilutions of chlorhexidine gluconate, a chlorous acid-chlorine dioxide irrigation solution, a chlorous acid-chlorine dioxide disinfectant, and phosphate buffered saline controls. Cell viability was determined by trypsinizing the cells, staining them with trypan blue, and counting cells that did not take the stain. All fibroblasts were killed when exposed to 1.0% and 0.5% chlorhexidine. The survival rate of fibroblasts increased linearly with decreasing concentrations of chlorhexidine gluconate, with a peak survival of 50% at 0.005% chlorhexidine. The chlorous acid-chlorine dioxide irrigation solution was the least toxic to fibroblasts, with survival rates equivalent to those of controls. The chlorous acid-chlorine dioxide disinfectant was 100% cytotoxic even when diluted 1:1 with phosphate buffered saline. S. aureus growth was inhibited by 1.0% and 0.5% chlorhexidine gluconate; concentrations of 0.05%, 0.01%, and 0.005% did not differ from sterile water controls. The chlorous acid-chlorine dioxide irrigation solution did not inhibit growth of S. aureus in brain-heart infusion broth. The chlorous acid-chlorine dioxide disinfectant inhibited growth of S. aureus.     

Prevention of intramammary infections in dairy cows by the use of a premilking teat dip method with a foaming iodophor dip agent

In this study we investigated the efficacy of premilking teat dipping with a foaming iodophor teat dip in a negative controlled field study. Incidence of new intramammary infections (IMI), incidence of clinical mastitis, influence on somatic cell count (SCC) and the characteristics of udder tissue and teats were used as parameters to evaluate clinical efficacy. Predipping was compared with a negative control using a split-udder experimental design. Right teats were predipped with a foaming disinfectant containing 0.27% iodine while left teats served as controls. The latter were conventionally cleaned with damp cloth towels and dried manually with disposable paper towels ("best cleaning practice"). All teats were dipped after milking with the same dip. There were no differences between treated and control quarters with respect to incidence of new IMI during the study period (treated quarters: 6.6% vs. untreated: 6.95%), incidence of clinical mastitis (30 cases in the treatment group vs. 39 cases in the control group) and geometric mean of SCC of quarter milk samples. Spectrum of detected pathogens was also comparable. Condition of udder tissue and teat ducts did not differ between treated and control quarters.     

The clinical effectiveness of a post milking teat disinfection method with a foaming iodophor teat dip

The effect of postmilking teat dipping with a foaming iodophor agent on incidence of intramammary infections (IMI), incidence of clinical mastitis, somatic cell count and the characteristics of udder tissue and teat was investigated in a positively controlled field study. Two groups of animals were compared. Teats were dipped with a foaming iodophor in the treatment group (TG, 122 animals) while teats in the control group (CG, 121 animals) were dipped with a conventional iodophor teat dip with the same iodine content. A bacteriological examination of quarter milk samples divided the study period in two parts. The incidence of new IMI did not differ between the groups (1st part of trial: TG vs. CG: 6.84% vs. 9.16%, 2nd part of trial: 7.78% vs. 7.82%). There were no differences between the treatment groups regarding incidence of clinical mastitis. We detected 0.64 clinical cases per 100 days in the treatment group vs. 0.50 in the control group. The development of SCC was comparable in both groups. Teat skin and teat duct conditions showed variation during the study period. Clinical efficacy of postmilking teat disinfection with a foaming iodophor was comparable to the treatment with a conventional iodophor product.     

Prophylactic efficacy of four antibacterial shampoos against Staphylococcus intermedius in dogs

Prophylactic efficacy of 4 antibacterial shampoos against Staphylococcus intermedius in dogs was determined by use of a controlled quantitative technique. Ten adult Beagles were used in the study. The antibacterial agents in the shampoos were 3.0% benzoyl peroxide, 0.5% chlorhexidine acetate, 1.0% available iodine as a polyalkyleneglycol-iodine complex, and a combination of 0.5% triclosan, 2.0% sulfur, and 2.0% salicylic acid. Treated and control sites were challenge exposed with 5.30 +/- 0.10 (log10) S intermedius colony-forming units (CFU)/cm2 of skin and occluded for 5 hours. At the end of the test period, remaining bacteria were removed with a detergent cup-scrub technique and the total number of S intermedius CFU/cm2 skin was calculated for each treated and control site. Nontreated bacteria-challenged control sites yielded 5.62 +/- 0.65 S intermedius CFU/cm2 of skin. Staphylococcus intermedius recovery (CFU/cm2) from the treated sites was 0.94 +/- 0.76 for benzoyl peroxide, 1.96 +/- 1.33 for chlorhexidine acetate, 3.11 +/- 0.48 for organic iodine, and 4.69 +/- 0.23 for triclosan-sulfur-salicylic acid. Each S intermedius recovery value from the 4 treated sites was significantly (P less than 0.05) lower than that from the nontreated S intermedius challenge-exposed control site. Bacteria recovery values were also significantly (P less than 0.05) different among the 4 shampoo-treated sites. We concluded that all shampoos had significant (P less than 0.05) prophylactic activity against S intermedius over 5 hours. The shampoo containing benzoyl peroxide was determined to have the greatest efficacy among the products tested.     

Fomites and reservoirs of Staphylococcus aureus causing intramammary infections as determined by phage typing: the effect of milking time hygiene practices

We studied the association of milkers' hands and milking unit liners as fomites, and teat skin as a reservoir, with S. aureus intramammary infections (IMI). Samples were collected from 40 commercial herds and S. aureus isolates were phage typed. Only 10 of 257 isolates were not typable. Of the milk samples, 8.4% had typable S. aureus; 4.5% and 9.2% of the skin and liner swabbings had typable S. aureus. Twenty-three different phage types were identified, 1 type was found in nearly 75% of the herds. Herds in which milking unit backflush was used were less likely to have the same phage type on the liners and the teat skin, and on the liners and milk samples, than herds that did not backflush. A greater percentage of liners had S. aureus of the same type as those causing S. aureus IMI, than skin swabbing solutions with the same type as that associated with IMI. Herds which did not use post-milking teat asepsis (teat dip) did not have a greater percentage of S. aureus isolates on the teat skin, nor were the S. aureus test skin isolates more likely to be of the same type as those causing intramammary infection. Results would suggest that the liner appears to be a significant fomite, that backflushing reduces its significance, and that teat skin is a less significant reservoir for S. aureus intramammary infection.     

The bactericidal effect of N-acetyl-beta-D-glucosaminidase on bacteria.

The bactericidal activity of N-acetyl-beta-D-glucosaminidase (NAGase) on some of the potential bacterial pathogens of the cow was determined. NAGase treatment significantly decreased the mean log10 number of Actinomyces pyogenes (P less than 0.01) and Staphylococcus aureus (P less than 0.05) after 2 and 4 hours of incubation at 37 degrees C. Similarly NAGase treatment significantly (P less than 0.05) reduced the mean log10 number of Streptococcus agalactiae and Pseudomonas aeruginosa after 4 hours incubation at 37 degrees C. NAGase did not reduce the numbers of Escherichia coli or Enterobacter aerogenes after either 2 or 4 hours incubation. Since NAGase and presumably other lysosomal enzymes are free on normal mucosal surfaces such as the uterus it is suggested that this direct bactericidal activity may be an important component of the normal defense mechanisms.     

Effect of pre-milking teat preparation procedures on the microbial count on teats prior to cluster application

A study was carried out to investigate the effect of six pre-milking teat preparation procedures on lowering the staphylococal, streptococcal and coliform microbial count on teat skin prior to cluster application. The teat preparations included 'Iodine', 'Chlorhexidine' teat foam, 'Washing and drying' with paper, 'No preparation', 'Chlorine' teat foam, and disinfectant 'Wipes'. Teat preparations were applied for five days to 10 cows for each treatment during two herd management periods (indoors and outdoors). Teats were swabbed on day four and five before teat preparation and repeated after teat preparation. The swabs were plated on three selective agars: Baird Parker (Staphylococcus spp.), Edwards (Streptococcus spp.), and MacConkey (coliform). Following incubation, microbial counts for each pathogen type were manually counted and assigned to one of six categories depending on the microbial counts measured. The results were analysed by logistic regression using SAS 28. The main analysis was conducted on binary improvement scores for the swabbing outcomes. There were no differences for staphylococcal, streptococcal and coliform bacterial counts between treatments, measured 'before' teat preparation. Treatments containing 'Chlorhexidine' teat foam (OR = 4.46) and 'Wipes' (OR = 4.46) resulted in a significant reduction (P < 0.01) in the staphylococcal count on teats compared to 'Washing and drying' or 'No preparation'. 'Chlorine' teat foam (OR = 3.45) and 'Wipes' (3.45) had the highest probability (P < 0.01) of reducing streptococcal counts compared to 'Washing and drying' or 'No preparation'. There was no statistical difference between any of the disinfectant treatments applied in reducing coliforms. Thus, the use of some disinfectant products for pre-milking teat preparation can have beneficial effects on reducing the levels of staphylococcal and streptococcal pathogens on teat skin.     

武夷岩茶茶多酚抑菌作用的研究

用纸片法测定了1.0、2.5、5.0、10mg/mL 4种浓度的武夷岩茶茶多酚对大肠杆菌、致病性大肠杆菌、李斯特氏沙门氏菌、金黄色葡萄球菌等4种菌的抑菌效果。实验结果表明,茶多酚对4种菌均有明显的抑菌作用,其中对金黄色葡萄球菌的抑菌作用最强（P〈0.01）,4种浓度的抑菌圈分别为1.82±0.44～3.34±0.18（cm）;对李斯特氏沙门氏菌、大肠杆菌、致病性大肠杆菌的抑菌作用次之,抑菌圈分别为1.73±0.18～2.05±0.14（cm）;1.46±0.33～1.85±0.32（cm）;1.1±0.14～1.61±0.25（cm）。1mg/mL的茶多酚对4种菌的抑菌作用均小于同剂量的青霉素和庆大霉素（P〈0.01）。     

苯扎溴铵－大蒜素复方消毒剂的杀菌效果试验

为了探明苯扎溴铵－大蒜素复方消毒剂的杀菌效果,根据兽用消毒剂鉴定技术规范的相关规定,用不同稀释倍数(500、1000、2000、4000倍)的该消毒剂在不同时间段(1、5、10、20 min)对5种细菌(金黄色葡萄球菌、大肠杆菌、多杀性巴氏杆菌、溶血性链球菌C型及蜡样芽孢杆菌)进行杀菌效果试验,同时以苯扎溴铵和大蒜油为对照试验组,观察和评价苯扎溴铵－大蒜素复方消毒剂的杀菌效果。结果表明在2000倍稀释的状态下该复方消毒剂对以上5种细菌表现出了完全的杀菌效果。因此,苯扎溴铵－大蒜素复方消毒剂在2000倍的稀释状态下能达到良好的杀菌效果,便于临床应用。     

Effect of teat dipping with a germicide barrier teat dip in late gestation on intramammary infection and clinical mastitis during the first 5 days post-partum in primiparous cows

The effect of teat dipping with a barrier teat dip prior to parturition on intramammary infection (IMI) and clinical mastitis during the first 5 days post-partum was investigated in a split udder trial in 149 Holstein-Frisian heifers. Their left front and right hind quarters were dipped three times weekly (i.e. Monday, Wednesday and Friday) with a barrier teat dip containing 0.1% polyvidon iodine from day 260 of gestation until parturition. The opposite quarters (right front and left hind quarter) served as untreated control. Bacteria were isolated from 52.2% of quarter milk samples collected immediately after parturition prior to first machine milking. Staphylococcus aureus and coagulase-negative staphylococci (CNS) were predominantly found in the samples (29.2 and 35.6% of the positive samples, respectively). At parturition 6.7% of the heifers showed signs of clinical mastitis and another 27.5% developed signs of clinical mastitis during the first five days of lactation. No significant differences were found between treated and control quarters regarding IMI and incidence of clinical mastitis. Teat dipping prior to parturition in primigravid dairy heifers did not improve udder health in this trial.     

中药复方及拆方组合的抗炎、镇痛、抑菌活性评价

目的：为了研究中药复方及其主要药味拆方组合的抗炎、镇痛、抑菌活性。方法：以二甲苯致小鼠耳肿胀模型及冰醋酸致小鼠毛细血管渗透试验观察其对炎症的影响;通过醋酸致小鼠扭体试验及热板法试验观察其对疼痛的影响;采用二倍稀释法测定其对大肠杆菌、金黄色葡萄球菌、沙门氏菌的最小抑菌浓度( MIC) 和最小杀菌浓度（MBC）。结果：中药复方组及拆方组合不能减轻二甲苯致炎小鼠的耳肿胀度和降低小鼠腹腔毛细血管通透性 (P>0.05);中药复方组、拆方组合都能极显著的减少小鼠扭体次数(P＜0.01),但对热刺激引发的小鼠痛反应时间无明显的延长 (P>0.05);中药复方在0.63 mg/mL浓度以上时对大肠杆菌、金黄色葡萄球菌表现出很好的抑菌效果,对沙门氏菌呈中度敏感,其MIC为9.375 mg/mL。然而,拆方组合抑菌效果不明显。结论：中药复方及其拆方组合具有一定的镇痛及抗菌活性。     

Teat lesions and their relationship to intramammary infections on small-scale dairy farms in Kiambu district in Kenya

Mammary gland quarters of 139 lactating dairy cows from small-scale dairy herds were examined visually and by palpation for teat lesions and by California mastitis test (CMT) and bacterial culture for subclinical mastitis. Teat lesions were observed in 97 teats. These included teat chaps (39.2%), teat papillomas (23.7%), teat erosions (22.7%), teat fistulae (5.1%), inverted teats (5.1%) and blocked teats (4.2%). According to the CMT, the prevalence of subclinical mastitis was 33.4% in all the mammary gland quarters, 71.0% in quarters with teat lesions and 24.5% in quarters without teat lesions. There was a significant (P < 0.01) association between teat lesions and the prevalence of subclinical mastitis. The mammary gland quarters with teat lesions were 7.2 times more likely to have a positive CMT (P < 0.01) and 5.6 times more likely to have bacterial organisms (P < 0.01) isolated from them than those without any teat lesions. The bacterial organisms most frequently isolated from the CMT-positive milk samples from both the mammary gland quarters with teat lesions and those without teat lesions were Staphylococcus aureus (50.0%), Streptococcus spp. (34.8%) and Arcanobacterium pyogenes (6.2%).     

Mastitis in a large, zero-grazed dairy herd

A zero-grazed herd of approximately 400 cows had a significant mastitis problem associated with Escherichia coli and Streptococcus uberis during a study over three and a half years. Dry cow therapy and post-milk teat dipping effectively controlled staphylococci and the bulk milk cell count averaged less than 400 X 10(3) cells/ml, but over 1800 clinical cases of mastitis occurred over this period, 32 per cent of which were associated with E coli and 25 per cent with Str uberis. Only 8 per cent of the cases associated with E coli showed obvious systemic disturbance and 75 per cent were cured following penicillin and streptomycin treatment. The incidence was highest during spring and summer when the housed cows were dirtiest. Gross teat-end contamination came mainly from sources other than cubicle bedding, and changing the bedding from sawdust to sand did not alter the incidence of clinical mastitis. It was not possible to maintain adequate cleanliness either inside or outside the parlour, nor maintain a trouble-free milking apparatus. The costs of mastitis in this herd during one year are calculated.     

Turkey macrophage and heterophil bactericidal activity against Pasteurella multocida.

Bactericidal activity of turkey macrophages and heterophils was demonstrated in an in vitro colorimetric bactericidal assay. Two vaccine strains and one field isolate of Pasteurella multocida A:3,4 and a single isolate each of Escherichia coli and Staphylococcus aureus were compared for susceptibility to the bactericidal activity of turkey macrophages and heterophils. Only P. multocida A:3,4-strain M-9 (the least virulent strain) was susceptible to macrophage bactericidal activity in the absence of specific immune serum, whereas all three P. multocida A:3,4 organisms were killed when opsonized with specific immune serum. E. coli was susceptible to the bactericidal activity of macrophages, and S. aureus was resistant. All bacteria tested were highly sensitive to the bactericidal activity of intact turkey heterophils, regardless of the opsonin treatment. Electron microscopic findings suggested that heterophils may kill extracellular P. multocida. Only S. aureus and E. coli were killed by lysed heterophils.     

Intramammary infections and risk factors for clinical mastitis in herds with low somatic cell counts in bulk milk

Ten herds with low somatic cell counts in bulk milk had an incidence of clinical mastitis of only 2.2 per 100 cows whereas 10 other herds with similarly low cell counts had an incidence of 53.6 per 100 cows. The major pathogens in the herds with a high incidence were Escherichia coli, Streptococcus uberis, Staphylococcus aureus and the coagulase-negative staphylococci. The percentage of uninfected quarters in the herds with a high incidence of clinical mastitis was 21.4 per cent compared with 12.2 per cent in the herds with a low incidence of clinical mastitis. The prevalence of coagulase-negative staphylococci, Corynebacterium bovis and Micrococcus species was higher in the herds with a low incidence of clinical mastitis. There was a significant linear relationship between the percentage of uninfected quarters and the incidence of clinical mastitis in the herds with a high incidence of clinical mastitis. In herds with a low incidence of clinical mastitis significantly less teat disinfection after milking was practised. The results suggest that infections with minor pathogens tend to protect cows against mastitis, and that teat disinfection after milking may increase the percentage of uninfected quarters and lead to an increased risk of clinical mastitis in herds with low somatic cell counts in bulk milk.