首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
Biofilm production by 221 Staphylococcus aureus isolates from 45 dairy herds was evaluated. Isolates were from composite milk of 117 cows, from teat skin of 70 cows, and from 34 milking machine unit liners. Of S. aureus from milk samples, 41.4% were biofilm producers, as compared to 24.7 and 14.7% of the isolates collected from skin and liners. Pulsed field gel electrophoresis (PFGE) best categorized S. aureus biofilm producers as compared to phage typing and binary typing. PFGE types that were significantly associated with isolation from milk as opposed to teat skin or liners, had isolates that were more likely to produce biofilm than PFGE types that were isolated from milk, skin and liners at similar frequencies. By contrast, PFGE type A was significantly associated with isolation from teat skin and had few biofilm producers. PFGE type Q, which is exclusively a milk, isolate produced more biofilm as evidenced by absorbance values. Given S. aureus that are associated with milk are more likely to produce biofilm as compared to extramammary sources (teat skin and milking unit liners), suggests that biofilm production is a risk factor for infection.  相似文献   

2.
The aim of the present study was to examine the diversity of Staphylococcus aureus isolates from bovine intramammary infections (IMI) in nine dairy herds, and compare these with isolates from other sites on the cows by phage- and ribotyping. Whether colonisation of milkers with S. aureus could be a source of infection for bovine IMI was investigated. In addition, 100 epidemiologically unrelated S. aureus isolates from asymptomatic human carriers were also phage- and ribotyped to compare the human and bovine reservoir of S. aureus in Denmark. A total of 625 S. aureus isolates from bovine IMI, bovine skin lesions, milking personnel, and non-farm-related human carriers were included in the study. Certain types predominated in one or several herds during the study period of one-and-a-half to two years, whereas the presence of other types was of a more sporadic nature. Within the individual herds, there was a close correspondence between ribo- and phage types of S. aureus isolated from bovine intramammary infections and skin lesions. Isolates from milking personnel, however, were not identical to any of the predominant intramammary strains. Furthermore, several of the isolates from milking personnel showed ribo- and phage patterns identical to S. aureus isolates from human carriers. The findings of the present study underline the importance of strict milking hygiene and improvement of current mastitis therapy. The results support the hypothesis that some S. aureus mastitis strains are more contagious, virulent or persistent than others. The human reservoir of S. aureus does not play a major role as a source of bovine intramammary infections.  相似文献   

3.
Four procedures were compared for isolation of Staphylococcus aureus from swabbing solutions of teat skin and milking unit liners from commercial dairies. In 2 procedures, 0.1 ml of swabbing solutions were added to either 5 ml Vogel-Johnson or Baird Parker broth media and enriched at 37 degrees C, 4 h. Following enrichment, 0.1 ml culture was transferred to modified Baird-Parker agar and incubated at 37 degrees C, 48 h. In the other 2 procedures, 0.1 ml of swabbing solution was directly placed on either blood or modified Baird-Parker agar plates and incubated at 37 degrees C 48 h. Combining results from all methods, Staphylococcus aureus were isolated from 72 of 913 (7.9%) skin samples, and 34 of 268 liners (12.6%). On average, 43.1% (31/72) of the S. aureus isolates were found by the enrichment in liquid Vogel-Johnson procedure. The average isolation percentage for other methods ranged from 19.4% to 25.0%. Isolation of S. aureus from milking unit liner or teat skin swabbing solutions was approximately twice as likely after enrichment in Vogel-Johnson liquid media as opposed to other methods of isolation. This indicates that enrichment in Vogel-Johnson liquid media improved recovery of S. aureus from swabbing solutions.  相似文献   

4.
Sixteen Holstein cows were used to test the effect of postmilking teat treatment on colonization and intramammary infection by Staphylococcus aureus on chapped teats. Treatments were (1) chapping the teat and using 1% I2/10% glycerin postdip solution, (2) 1% I2/10% glycerin postdip solution on nonchapped teats, (3) chapping the teat and using 10% glycerin postdip solution, (4) chapping the teat and not using a postdip solution. All mammary glands were free of S aureus teat skin colonization and intramammary infection at the start of the study. Teats selected for chapping were dipped in 1N NaOH prior to 3 applications of S aureus broth culture; cultures were applied at 12-hour intervals on all teats. Treatments were applied after each milking for 30 days and were initiated after the second broth dip. Teat skin swab specimens and milk samples were collected before treatment application. Teat skin condition was scored daily. Nonchapped teats (treatment 2) did not support skin or orifice colonization by S aureus. Treatment-1 teats healed most rapidly and supported less colonization in skin and orifice than did treatment-3 and -4 teats. Teat skin scores and skin colonization were lower for treatment-3 than treatment-4 teats. A correlation between teat skin colonization and teat skin conditions was found. Two intramammary infections were found in treatment-4 quarters and 1 in a treatment-3 quarter.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

5.
The effectiveness of monthly removal of hair surrounding teats on the reduction of teat skin surface bacteria, and the incidence of intramammary infection (IMI), was studied for 10 months in a dairy farm. A split udder design was used where hair was removed on one side, left or right, with the other side serving as a control. Controls and treatment sides were randomly applied in a systematic fashion to 218 cows. Standard milking time pre- and post-milking hygiene practices were applied to all udders during the trial. Collection of teat skin swab solutions preceded aseptic collection of milk samples, performed at monthly intervals, immediately prior to milking. Teat skin bacterial counts did not differ between control and treated teats. Incidences of IMI were similar for treatment when compared with control mammary quarters, as measured by total or by pathogen type. In a second study, the effect of hair removal on the bacterial content of milk was determined using 40 cows. Treatments and allocations were as described. Udder half milk, milk from both mammary quarters of each udder half, was combined and diverted into separate buckets. Buckets were thoroughly cleaned and sanitized between milkings. A portion of bucket milk was collected 24 h after removal of udder hair. The total milk bacterial counts, and counts of psychrotrophs and thermoduric organisms were not reduced by udder hair removal. Results do not suggest that removal of udder hair leads to an improvement in milk quality as determined by milk bacterial content in the herd studied.  相似文献   

6.
The hypothesis that strains of Staphylococcus aureus are more likely to be unique to a herd than common to several herds was tested. Herds (n=28) from nine geographic areas of Korea, with elevated milk somatic cell counts (>500000 cells/ml) were enrolled in this study. Mammary quarter milk samples were aseptically collected from all lactating cows (n=616) with at least three functional quarters. Milk was cultured and S. aureus isolates were typed using pulse field gel electrophoresis of DNA SmaI digests. A total of 181 cows were identified as having S. aureus intramammary infections. A total of 52 different types of S. aureus were identified and 34 (65.4%) were associated with a single herd. A total of 18 types of S. aureus were found in multiple herds; 14 types were found in two herds, and four types were found in three herds. Herds with 1, 2, 3, and more than 3 types, were: four (14.3%); eight (28.6%); nine (32.1%); and seven (25.0%). The data indicate that the majority of strains were found in one herd only, and more than 90% were found in two or less herds, suggesting that strains of S. aureus are more likely to be restricted to a single herd, than found in multiple herds.  相似文献   

7.
A study of the characterization of the phenotypic patterns of Staphylococcus aureus strains isolated from bovine subclinical mastitis in Israeli dairy herds and their correlation with the severity of the disease was undertaken. A total of 400 chronically S. aureus-infected Israeli-Holstein cows, from 15 dairy herds were included in this study. Based on the results of the biochemical reactions, of the anti-biogram and phage typing, one major type of S. aureus was determined in each herd, its prevalence being between 54 and 100% of the total isolates from that same herd. The majority of the isolates were found to be non-haemolytic (62.7%). The most common phage type was 3/A,3/C,55,71, which was predominant in five herds. In two herds none of the isolates (24) were typable by this set of phages. All isolates were susceptible to methicillin, erythromycin, cephalotin, norfloxacin, trimethoprin-sulphamethoxazole and novobiocin. Most isolates were resistant to penicillin (96.6%) and 52% to oxytetracyclin. Differences in protein patterns between 50 and 36 kDa were found by one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis. No correlation between any combination of the phenotypic characteristics was found when correlation was done with milk yield and somatic cell count, corresponding to the 6 months before sampling. Otherwise, a positive correlation was found between type of haemolysis and the N-acetyl-beta-glucosaminidase (NAGase) values. In milk from quarters infected with the-non-haemolytic strains, the level of NAGase was significantly lower (P < 0.05) than that from quarters infected with the haemolytic strains (69.7 and 105.9, respectively). However, the level of NAGase activity in the milk of the quarters infected with the non-haemolytic strains was significantly higher (P < 0.05) when compared to the milk of quarters infected with coagulase-negative staphylococci (43.5).  相似文献   

8.
Sawdust was aspirated into one of the teatcups of the milking unit by induced liner slip during milking of 10 cows, which were then slaughtered. Sawdust particles were recovered from the interior of the quarters, the teat skin and the inside of the liners corresponding to both treated and untreated teats, and from the milk claw and the bucket as well. Sterile sawdust was introduced into the teat cisterns of three quarters of one cow. Clinical mastitis developed. The investigation was initiated by an outbreak of Serratia-mastitis in a dairy herd and supports the view that the outbreak was caused by contaminated sawdust used as litter in combination with improper detachment of the milking units. Widening of the impact concept is propsosed.  相似文献   

9.
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.  相似文献   

10.
A placebo-controlled field study was performed to evaluate the effect of a herd-specific vaccine against Staphylococcus aureus on intramammary infection (IMI), somatic cell count (SCC) and clinical mastitis. Three hundred and twenty-one heifers were assigned to two groups. Heifers in the vaccination group (n = 164) were vaccinated twice, i.e. 5 and 2 weeks before their expected calving date. Animals of the control group (n = 157) received the same treatment with a placebo containing no bacterial antigen. Quarter milk samples were collected immediately after parturition prior to the first machine milking, 3-4 weeks after calving and before the onset of treatment in animals with signs of clinical mastitis during the first 3 months after calving. For comparison of SCC the data from the monthly milk test records were evaluated. The prevalence of S. aureus in quarter milk samples taken at calving and 3-4 weeks post-partum did not differ significantly between the vaccine and control group. Incidence of clinical mastitis during the first 3 months after calving and the prevalence of S. aureus in quarter milk samples taken before the onset of treatment did not differ significantly between the groups. The SCC was lower in vaccinated than in control heifers. However, the difference was only significant on the third milk test day. Regarding prevalence of IMI with S. aureus and incidence of clinical mastitis the use of a herd-specific vaccine against S. aureus did not prove to be efficient on this farm.  相似文献   

11.
OBJECTIVE: To determine the epidemiologic pattern of intramammary infections (IMIs) with Staphylococcus aureus during implementation of a control program in 9 commercial dairy herds. DESIGN: Cohort study. ANIMALS: 1,651 lactating cows and 53,098 quarter milk samples. PROCEDURES: Nine herds located in different regions of Italy were enrolled. Control of S. aureus infections followed the general principles of contagious mastitis control and was based on precise diagnostic procedures and strict control and segregation of infected cows. All lactating cows in each herd were tested, and those free of S. aureus IMI were enrolled as the cohorts. Further additions to the cohort group were cows and heifers free of S. aureus IMI, as determined from aseptically collected milk samples taken approximately 7 and 14 days after calving. RESULTS: After the ninth month of the program, incidence decreased to < 2 new IMIs/100 cow-months in 7 of the herds. At the end of the study, 8 of 9 herds had an incidence of < or = 1 new IMI/100 cow-months. Heifers were most at risk of developing an IMI. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that control of S. aureus IMIs can be achieved by use of a control program based on segregation and use of hygienic and therapeutic protocols. Analysis of incidence and identification of risk factors in a herd could avoid the possible shortcomings of the program, maximizing the probability of success.  相似文献   

12.
The use of PCR tests as diagnostics for intramammary infections (IMI) based on composite milk samples collected in a non-sterile manner at milk recordings is increasing. Carryover of sample material between cows and non-aseptic PCR sampling may be incriminated for misclassification of IMI with Streptococcus agalactiae (S. agalactiae) in dairy herds with conventional milking parlours. Misclassification may result in unnecessary costs for treatment and culling. The objectives of this study were to (1) determine the effect of carryover on PCR-positivity for S. agalactiae at different PCR cycle threshold (Ct) cut-offs by estimating the between-cow correlation while accounting for the milking order, and (2) evaluate the effect of aseptic presampling procedures (PSP) on PCR-positivity at the different Ct-value cut-offs.  相似文献   

13.
It was the aim of this study to investigate the effect of various factors of the milking technique, milking hygiene and environment on microbial contamination of the milking machine. In 31 dairy herds, the degree of bacterial contamination was examined by taking swabs at four locations (teat cup liner, claw, short and long milk tube) before the milking procedure was started using a standardized protocol (DIN ISO 6887-1:1999). Furthermore, the total germ count was determined in the first milk entering the bulk tank as well as in the bulk tank milk following milking. For each farm, the quality of the milking process and the condition of the milking machine as well as of various environmental factors were recorded. A subjective evaluation of the status of the milking cluster or other parts of the milking machine ("good" or "moderate-poor") gave more information about bacterial contamination than the determination of age and type of material used. A temperature of the rinsing water of < 42 degrees C increased the contamination with Pseudomonas spp. and coliform bacteria. Milking clusters kept out of the cluster pick-up between milking had a higher risk of microbial contamination. Various methods of teat cleaning before milking or of postmilking teat disinfection did not affect the contamination of the milking machine and the bulk tank milk with environmental bacteria. Furthermore, type of bedding material affected bacterial contamination of milking clusters and bulk tank milk. In conclusion, our results suggest that the microbial contamination of the milking machine is not only influenced by the sanitation pro-  相似文献   

14.
: Friesian-type dairy cows were milked with different machine settings to determine the effect of these settings on teat tissue reaction and on milking characteristics. Three teat-cup liner designs were used with varying upper barrel dimensions (wide-bore WB = 31.6 mm; narrow-bore NB = 21.0 mm; narrow-bore NB1 = 25.0 mm). These liners were tested with alternate and simultaneous pulsation patterns, pulsator ratios (60:40 and 67:33) and three system vacuum levels (40, 44 and 50 kPa). Teat tissue was measured using ultrasonography, before milking and directly after milking. The measurements recorded were teat canal length (TCL), teat diameter (TD), cistern diameter (CD) and teat wall thickness (TWT).Teat tissue changes were similar with a system vacuum level of either 50 kPa (mid-level) or 40 kPa (low-level). Widening the liner upper barrel bore dimension from 21.0 mm (P < 0.01) or 25.0 mm (P < 0.001) to 31.6 mm increased the magnitude of changes in TD and TWT after machine milking. Milk yield per cow was significantly (P < 0.05) higher and cluster-on time was reduced (P < 0.01) with the WB cluster as compared to the NB1 cluster. Minimum changes in teat tissue parameters were achieved with system vacuum level of 40 kPa and 50 kPa using NB and WB clusters, respectively. Similar changes in teat tissue and milk yield per cow were observed with alternate and simultaneous pulsation patterns. Widening pulsator ratio from 60:40 to 67:33 did not have negative effects on changes in teat tissue and had a positive effect on milk yield and milking time. Milk liner design had a bigger effect on teat tissue changes and milking characteristics than pulsation settings.  相似文献   

15.
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.  相似文献   

16.
: Milk samples from 285 cows in 15 dairy herds were collected for bacteriological analysis. Cows were selected on the basis of a somatic cell count (SCC) exceeding 200,000 cells per ml at the three most recent milk recordings prior to sampling. Staphylococcus aureus and Streptococcus uberis were the predominant isolates accounting for 21% (n = 61) and 19% (n = 53) of isolates, respectively. Streptococcus uberis was more frequently isolated from split-calving herds than from spring-calving herds and this difference was statistically significant (P < 0.005). Herds with suboptimal housing had a significantly greater prevalence of S. uberis than did herds where housing was adequate (P < 0.005). The isolation rates for S. aureus was significantly greater in herds where parlour hygiene was suboptimal (P < 0.05).  相似文献   

17.
Eight Danish Holstein cows were milked with a 1-mm thick specially designed soft liner on their right rear teat and a standard liner mounted under extra high tension on their left rear teat. Four of the animals were overmilked for 5 min. Rear teats were subjected to ultrasound examination on the first day and to infrared thermography on the second day. Teats were submersed in ethanol 20 min post-milking on the second day. Ultrasonography measurements showed that teat canal length increased by 30-41% during milking. Twenty minutes after milking, teats milked with modified standard liners still had elongated teat canals while teats milked with the soft liner were normalized. Overmilking tended to increase teat wall thickness. Approximately 80% of variability in teat canal length, from before teat preparation to after milking, could be explained by changes during teat preparation. Thermography indicated a general drop in teat temperature during teat preparation. Teat temperature increased during milking and continued to increase until the ethanol challenge induced a significant drop. Temperatures approached pre-challenge rather than pre-milking temperatures within 10 minutes after challenge. Teat temperatures were dependent on type of liner. Mid-teat temperatures post-challenge relative to pre-teat preparation were dependent on overmilking. Thermography and ultrasound were considered useful methods to indirectly and non invasively evaluate teat tissue integrity.  相似文献   

18.
In a herringbone milking parlour, teat cup liners were deliberately contaminated in turn with Staphylococcus aureus, Escherichia coli, Streptococcus agalactiae and Sterp uberis. Contamination was achieved by filling the liners with milk that contained 10(6) test organisms per ml. After the clusters had been back-flushed with water at 85 degrees C for five seconds, normal swabbing methods failed to recover any contaminating organisms from the teat liners in 56 tests out of 64. After 10 seconds back-flushing no recoveries were made in the same number of tests. The apparatus developed to effect this back-flushing for a particular herringbone parlour is described, with details of its routine use during milking. For a 100-cow herd, the running cost of such equipment using a five-second back-flush is estimated at no more than 4 pounds per week and, in its present form, would not add more than 10 seconds to the total milking time for each cow. Improvements in design of the apparatus, and in milking techniques arising from the routine use of the device, are also considered.  相似文献   

19.
Staphylococci are a major cause of intramammary infections (IMI) in ruminants. The main aim of this study was to investigate staphylococcal IMI in dairy cattle with emphasis on persistence and distribution of staphylococcal species and genotypes. With a sampling interval of 4-8 weeks, over a year, 4030 samples from 206 cows in 4 herds were collected. Coagulase-negative staphylococci (CNS) and Staphylococcus aureus were detected in 13.2% and 4.2% of the samples, respectively. Selected CNS isolates from quarter milk samples were identified to species level using sodA sequencing. Staphylococcus chromogenes (32%) and Staphylococcus simulans (25%) predominated. The proportion of S. chromogenes was greater in primiparous (52%) than in multiparous cows (12%), while the opposite was the case for Staphylococcus epidermidis (6% and 21%, respectively). Isolates from possibly persistent IMI were selected for pulsed-field gel electrophoresis (PFGE). Six staphylococcal species were found to cause persistent IMI; S. aureus, S. chromogenes, S. simulans, S. epidermidis, Staphylococcus haemolyticus and Staphylococcus warneri. It was shown that several pulsotypes (PTs) within each species were associated with persistent infections, but only a few were spread and caused persistent IMI in multiple cows within a herd. Of special interest was the observation that only one, or a few, strains of each species caused persistent IMI in multiple cows within a same herd. This indicates strain differences with respect to transmissibility and pathogenicity.  相似文献   

20.
AIM: To assess the effect of applying an external teat sealant or a slow-release intraruminal monensin capsule pre-calving on the prevalence and incidence of subclinical or clinical mastitis in dairy heifers post-calving. METHODS: The studies were undertaken in 13 herds. In two herds application of an external teat sealant was compared with a negative control; in nine herds treatment with monensin was compared with controls, and in two herds treatments were applied in a 2 x 2 factorial design. Heifers were randomly assigned within herd to be treated with a slow-release intraruminal device containing 32 g monensin (n=383), or left as untreated controls (n=389), approximately 30 days before the start of the spring calving period; or to be treated with a latex external teat sealant (n=206) when calving was impending, or be left as untreated controls (n=205). Milk samples were collected from each gland between 0 and 5 days after calving and from any gland diagnosed with clinical mastitis. The effect of the treatments on the prevalence of intramammary infection (IMI), i.e. subclinical mastitis, and clinical mastitis were initially analysed at the univariate level, with associated variables (p<0.2) being used in construction of multivariable models. RESULTS: The prevalence of IMI was 18.4% at the gland level, and coagulase-negative staphylococci followed by Streptococcus uberis were the most common isolates. Treatment with an external teat sealant reduced the prevalence, compared with controls, of any IMI (12.1 (SE 1.7)% vs 16.5 (SE 2.1)%, respectively; p=0.05) or IMI caused by a major pathogen (3.8 (SE 0.8)% vs 6.0 (SE 1.1)%, respectively; p=0.05). Monensin treatment did not affect the prevalence of any IMI (p=0.68) or IMI due to a major pathogen (p=0.11). The cumulative incidence of clinical mastitis was 14.2%. Neither monensin treatment (p=0.47) nor application of an external teat sealant (p=0.71) altered the risk of clinical mastitis. There was no interaction between the monensin and external teat sealant in the two herds where the treatments were applied in a 2 x 2 factorial design. CONCLUSIONS: Application of an external teat sealant resulted in a lower prevalence of any IMI and of an IMI caused by a major pathogen. Despite monensin reducing the mobilisation of body tissue and the risk of subclinical ketosis, it had no effect on the prevalence or incidence of IMI or clinical mastitis. CLINICAL RELEVANCE: Application of an external teat sealant is an option for reducing the prevalence of IMI in pasture fed dairy heifers.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号