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 31 毫秒
1.
Ninety-eight Staphylococcus aureus isolates and 227 coagulase-negative staphylococcal isolates from turkeys were assayed for protein A content. The amount of protein A of each isolate was quantitated using a direct enzyme-linked immunosorbent assay. Of the S. aureus isolates, 83% possessed some protein A, whereas only 13% of the coagulase-negative staphylococci contained some protein A. No correlation was seen between protein A content and ability to adhere to turkey cells. No differences in virulence were seen between isolates of S. aureus possessing high or low levels of protein A; however, an isolate with no protein A was avirulent.  相似文献   

2.
Staphylococcus aureus and various coagulase-negative staphylococci were isolated from turkeys with staphylococcosis. Virulent S. aureus adhered well (averaged more than 100 bacteria per tissue cell) in vitro to cells from tissues of the respiratory tract but did not adhere well (averaged fewer than 12 bacteria per tissue cell) to cells from tissues of the alimentary tract. Some avirulent coagulase-negative staphylococci also adhered well to cells from the respiratory tissues. Lungs and livers of turkeys became colonized with virulent S. aureus following experimental aerosol exposure. Tracheas, livers, and hock joints of some market-age turkeys were naturally colonized with S. aureus and various species of coagulase-negative staphylococci.  相似文献   

3.
Staphylococcus epidermidis strain 115 was used as an interfering agent to reduce the incidence of staphylococcosis in turkeys. In 1984, the entire Utah turkey population of about 3 million turkeys was exposed at 1 to 10 days and at 4 to 6 weeks of age to aerosols of strain 115. Some staphylococcosis was still observed in range turkeys but appeared to be at a lower rate than in previous years. At processing, about 30% of the turkeys were still colonized with strain 115. A control study was carried out in 1985 to quantitate the level of reduction of staphylococcosis in turkeys treated with strain 115. About 1 million turkeys were treated, and 2 million remained untreated. Flocks from both groups were examined periodically for existing cases of staphylococcosis. Of 174,250 treated turkeys examined, 90 had staphylococcosis on the days examined, whereas 255 of the 183,500 untreated turkeys that were examined had staphylococcosis. Turkeys housed in range sheds had five times the incidence of staphylococcosis that turkeys in enclosed coops had. The gross mortality rate of 200,636 treated turkeys was 2.7% lower (P less than 0.001) than that of 189,450 untreated control turkeys that were monitored.  相似文献   

4.
Previous studies indicated that Staphylococcus epidermidis strain 115 might be an effective interfering agent in reducing the rate of staphylococcosis in turkeys. In the present study, strain 115 was avirulent when administered to 3-day-old chicks by oral, aerosol, or intravenous route. Strain 115 adhered specifically to tracheal, lung, air-sac, and liver cells in vitro and interfered with subsequent colonization by virulent Staphylococcus aureus. In vivo colonization of lungs and livers of young chicks occurred following exposure to aerosols of strain 115. Strain 115 interfered with the in vivo colonization of lungs and livers by virulent S. aureus.  相似文献   

5.
OBJECTIVE: To determine whether particular antimicrobial susceptibility profiles of bovine mastitis-causing Staphylococcus aureus isolates were associated with specific S aureus genotypes. SAMPLE POPULATION:357 S aureus isolates recovered from milk samples submitted for diagnostic bacteriologic testing from 24 dairy herds. PROCEDURES: Antimicrobial susceptibility of S aureus isolates was assessed by determining minimum inhibitory concentrations (MICs) to 14 antimicrobial agents. After digestion of S aureus genomic DNA by SmaI, electrophoretic patterns were obtained via pulsed-field gel electrophoresis (PFGE) and used to classify isolates into types. Gels were analyzed, and data were used to prepare dendrograms. RESULTS: 308 of 357 (86%) S aureus isolates were susceptible to all antimicrobials evaluated. Forty-nine S aureus isolates were resistant to 1 or more antimicrobials; of these isolates, 37 were resistant only to penicillin, 9 were resistant to penicillin and erythromycin, 2 were resistant to tetracycline, and 1 was resistant to erythromycin. Isolates were assigned to 7 PFGE types. An association was found between PFGE type and antimicrobial susceptibility profile. Organisms with resistance to at least one of the tested antimicrobial agents were identified in only 4 of the 7 types of S aureus. CONCLUSIONS AND CLINICAL RELEVANCE: Antimicrobial resistance was uncommon among the mastitis-causing S aureus isolates identified in the milk samples. A limited number of genotypes were associated with mastitis in these herds. Antimicrobial resistance phenotypes were associated with particular S aureus PFGE types; this association may have implications for future treatment and control of S aureus-associated mastitis in cattle.  相似文献   

6.
A vaccine composed of three field isolates of Staphylococcus aureus (S. aureus) derived from cases of mastitis in cows was developed. The vaccine was administered to nine uninfected cows while 10 other cows were used as controls. All cows were challenged with a highly virulent S. aureus strain administered into two quarters of each cow. Quarters were tested for clinical signs, secretion of S. aureus, and somatic cell count (SCC). No systemic effects were observed in any of the cows, vaccinated or control. Vaccinated cows had 70% protection from infection compared with fewer than 10% in the controls. Moreover, all quarters challenged in the vaccinated cows, regardless of whether they were successfully infected or not with S. aureus, exhibited very mild inflammatory reactions, identified by their low SCCs (<100,000).  相似文献   

7.
Fifty-one coagulase-positive staphylococcal isolates from canine urinary calculi or from the urine of dogs with documented urolithiasis, and 17 coagulase-positive staphylococcal isolates from human beings and cattle were identified by a commercially available tray micromethod, as well as by conventional methods. Canine isolates had previously been classified as Staphylococcus aureus on the basis of a positive tube coagulase test. After 5 hours' incubation, the tray method identified all 51 canine urolithiasis isolates as S intermedius, rather than S aureus. All human and bovine isolates were identified as S aureus. Conventional methods supported these findings.  相似文献   

8.
Fifty-five serotype 3,4 isolates of Pasteurella multocida, isolated from turkeys dead from fowl cholera, were characterized (fingerprinted) genotypically for comparison with the serotype 3,4 live fowl cholera vaccine principally used in turkeys in California. Twenty-three isolates were obtained from turkeys vaccinated with the M9 live vaccine, and 32 additional isolates were from turkeys not vaccinated for fowl cholera. Methods of characterization included restriction endonuclease analysis of chromosomal DNA and ribotyping, a technique for highlighting restriction site heterogeneity of highly conserved ribosomal RNA genes and associated sequences using a radiolabeled rRNA probe. Eight different genotypes or ribotypes were detected in these isolates by the above methods. Of 23 isolates from M9-vaccinated turkeys flocks, 19 were the same ribotype as M9. Thirty of 32 isolates recovered from unvaccinated turkeys were different ribotypes from M9. The remaining two isolates resembled M9 and were recovered from two different flocks placed in succession on a turkey farm where a flock placed previously had been vaccinated with M9, suggesting interflock transmission. Ribotyping and restriction endonuclease analysis appear to be useful tools to aid in the determination of the role that the live vaccine plays in fowl cholera epidemiology.  相似文献   

9.
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.  相似文献   

10.
Three slide agglutination tests for identification of Staphylococcus aureus were compared. The agglutination tests used for evaluation were Staphaurex (Wellcome Diagnostics), Staphyslide-Test (BioMerieux), and ANI S. aureus TEST (Ani Biotech Oy). A total of 347 isolates were analyzed, including 288 strains of S. aureus, 49 of S. epidermis, 11 of S. intermedius, 12 strains of other staphylococci and 14 non-staphylococcal strains. One hundred of the S. aureus strains were isolates from cases of food poisoning, 129 from mastitis and 59 from other clinical cases. The sensitivities of the tests were also compared using diluted suspensions of S. aureus strains and with purified Protein A dilutions. The results showed that the sensitivities of the tests were 98.6%, 97.9% and 99.0% for Staphaurex, Staphyslide-test and ANI S. aureus TEST, respectively. The specificities were 100% for the Staphyslide test and 98.8% for both the ANI S. aureus TEST and the Staphaurex test. The sensitivities measured with diluted S. aureus strain suspensions and Protein A solutions were equal with the Staphaurex and ANI S. aureus TEST. All the agglutination tests studied proved to be practical, easy to use and accurate for the rapid identification of S. aureus strains from culture isolates.  相似文献   

11.
Swabs of the oropharynges of 801 live turkeys (621 meat birds and 180 breeders), collected from 15 flocks that had experienced an outbreak of fowl cholera and from 12 non-outbreak flocks, were screened for the presence of Pasteurella multocida. Turkeys from outbreak flocks were sampled within 2 to 9 weeks of the outbreak. Forty-nine isolates of P. multocida were recovered from turkeys in 11 of the outbreak flocks, and none were recovered from turkeys in non-outbreak flocks. Isolation rates varied from 0 to 72% of turkeys sampled in a flock. Nineteen isolates were tested for virulence by injecting them intravenously into turkeys, and 14 were lethal. Results demonstrated that for purposes of disease control, meat birds in fowl-cholera-outbreak flocks should be considered carriers of potentially virulent P. multocida for the life of the flock.  相似文献   

12.
Samples collected from the oropharynx of wild mammals and birds trapped on 36 turkey farms in California were evaluated for the presence of Pasteurella multocida. A total of 966 animals were collected from 18 premises that had experienced an outbreak of fowl cholera within the past 2-8 months; samples were collected from 16 of these 18 premises within 2-8 weeks of outbreak notification and while the infected flock was still present. A total of 939 animals were trapped from an additional 18 premises that had not reported any outbreaks of fowl cholera within at least 4 months, if ever. Forty-eight isolates of P. multocida, of a variety of somatic serotypes, were recovered from 6 species of mammals and 3 species of birds. On only 2 of 7 premises was the somatic serotype of the isolates obtained from wildlife the same as the isolate obtained from tissues of turkeys that had died of fowl cholera on the same premises. Tests for virulence to turkeys were conducted with 31 of the isolates. Seventeen of these isolates caused mortality in turkeys. Wide ranges in mortality rates and median times to death were observed.  相似文献   

13.
Chloramphenicol resistance (CmR) could be detected in 11 of 217 Staphylococcus aureus isolates from bovine subclinical mastitis. All isolates were assigned to biotypes A or C. The CmR-determinants were found to be located exclusively on small plasmids of approximately 4.6 kb as revealed by protoplast transformation. The 11 CmR-plasmids could be differentiated on the basis of restriction endonuclease analyses. The restriction maps of these CmR-plasmids identified two separate groups. One group demonstrated homology to the plasmid pC 221, the other to the plasmid pC 223. Both prototype plasmids, pC 221 and pC 223, had been isolated from S. aureus of human origin.  相似文献   

14.
The species distribution, susceptibility to 19 antimicrobial agents and presence of selected genes encoding resistance to macrolides, streptogramins and tetracyclines were examined among 118 staphylococcal isolates from infections of poultry in Denmark. Isolates were identified using a combination of conventional biochemical testing and 16S rDNA sequencing. The most common species were Staphylococcus aureus (83), Staphylococcus hyicus (11), Staphylococcus xylosus (9) and Staphylococcus cohnii (6). The isolates were susceptible to most antimicrobials tested. A high frequency of S. aureus (30%) was resistant to ciprofloxacin. Only six (7%) S. aureus isolates and one Staphylococcus saprophyticus were penicillin resistant. Resistance to sulphamethoxazole was observed among 16 (19%) of S. aureus isolates and two coagulase negative staphylococci (CNS). Twenty (24%) of the S. aureus isolates were resistant to erythromycin and 19 of these isolates contained the ermA gene, whereas the remaining isolate contained the ermC gene. Eleven (48%) of the novobiocin resistant CNS were resistant to erythromycin and all these isolates contained the ermA gene. Two isolates identified as S. xylosus, were found to be resistant to streptogramins and both contained the vatB- and the vgaB-genes. Thirty-nine (47%) of the S. aureus isolates, three of nine S. hyicus and eight of the 23 novobiocin resistant CNS were tetracycline resistant and all contained the tet(K) gene. A single S. aureus isolate also contained the tet(M) gene. The present study showed a frequent occurrence of resistance to fluoroquinolones, tetracycline and macrolides among staphylococci isolated from broilers in Denmark, whereas the occurrence of resistance to other antimicrobial agents remains low. Similar genes, encoding resistance to erythromycin, tetracycline and streptogramins to those previously observed, were detected.  相似文献   

15.
A total of 150 isolates of Staphylococcus aureus were subjected to the tests on the API Staph system. Of these, 50 were also tested by conventional methods, using the same tests as those found on the API Staph strips. Applying the principles of numerical taxonomy, the relationship between these isolates was 82% and more. Tests for the metabolism of sucrose and N-acetyl-glucosamine and for the production of argenine dihydrolysate and urease appear to be superfluous in the identification of S. aureus in this system.  相似文献   

16.
PCR-assays for the detection of staphylococcal enterotoxins A-E, and H, toxic shock toxin 1, and exfoliative toxins A and B were evaluated against phenotypic methods, and performed well. Four hundred and fourteen isolates of Staphylococcus aureus from Danish cases of bovine mastitis were screened for genes encoding these superantigens. One hundred isolates from Danish human carriers were also included in the study. In contrast to the frequent presence of genes encoding and in vitro expression of superantigens among the human carrier isolates, only one of 414 isolates from bovine mastitis carried the genes encoding enterotoxin C and toxic shock toxin-1. These results further support the hypothesis that the bovine and human S. aureus reservoirs constitute two separate sub-populations of the species S. aureus. The results also show that these superantigens are generally not present in Danish S. aureus isolates from bovine mastitis, and thus play no essential role in the pathogenesis of bovine S. aureus mastitis.  相似文献   

17.
In this study, bacterial cultures were collected from five sites on each of 50 healthy cats and 48 cats with inflammatory skin disease (ISD), to determine prevalence of carriage and relative frequency of methicillin resistance in coagulase-positive staphylococci and Staphylococcus schleiferi ssp. schleiferi. Latex agglutination testing for penicillin-binding protein 2a (PBP2a) and pulsed field gel electrophoresis (PFGE) were performed on all methicillin-resistant (MR) isolates. Polymerase chain reaction (PCR) for the mecA gene was performed on MR S. intermedius and S. schleiferi isolates. Staphylococcal chromosomal cassette (SCCmec) typing was performed on all MR S. aureus isolates. Coagulase-positive staphylococci and S. schleiferi ssp. schleiferi were isolated from 24 of 48 cats with ISD: Staphylococcus aureus (14 of 24, 58%), Staphylococcus intermedius (11 of 24, 46%), Staphylococcus schleiferi ssp. schleiferi (1 of 24, 4%), and Staphylococcus hyicus (1 of 24, 4%). Prevalence of MR was 7% for S. aureus, 0% for S. intermedius, 100% for S. schleiferi ssp. schleiferi, and 0% for S. hyicus. Coagulase-positive staphylococci were isolated from 17 of 50 healthy cats: S. aureus (10 of 17, 59%), S. intermedius (11 of 17, 65%), and S. schleiferi ssp. coagulans (1 of 17, 6%). Prevalence of MR was 20% for S. aureus, 18% for S. intermedius, and 0% for S. schleiferi ssp. coagulans. All MR isolates were positive for PBP2a via latex agglutination. Methicillin-resistant S. intermedius and S. schleiferi ssp. schleiferi isolates were also positive for the mecA gene via PCR. Methicillin-resistant S. aureus isolates were identified as SCCmec type II. Results of PFGE indicated heterogeneity among isolates. There was no significant difference in staphylococcal isolation or methicillin resistance between study groups. While present, MR coagulase-positive staphylococci are significantly less common in these study populations.  相似文献   

18.
Lee JH 《Veterinary microbiology》2006,114(1-2):155-159
From 2001 to 2005, various specimens from cattle, pigs, and chickens were collected and examined for the presence of methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA). The isolates from 19 specimens were tested for the presence of the mecA gene. Methicillin resistance was confirmed by determining the MICs for these isolates. Among these 19 mecA-positive isolates, 16 were consistently found to be resistant to methicillin. The mecR1 gene was found in all 19 mecA-positive S. aureus, and mecI was also detected in 15 of the mecA-positive S. aureus. The mecI gene had an identical sequence to the reference sequence in 9 of the 15 mecI-positive isolates. Three of the other six isolates had a C to T substitution at nucleotide 202, and one had a G to T substitution at nucleotide 43. These have been previously identified in MRSA from humans. Two isolates from chickens contained an addition of C at position 23. This mutation of MRSA has not been reported elsewhere. In all 15 mecI-positive MRSA, the sequence of the mec promoter/operator region was identical to the reference sequence. This suggests other mechanisms for overcoming the repression of resistance caused by mecI, beyond the simple product interaction between the mecA, mecRI, and mecI genes.  相似文献   

19.
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   

20.
Mastitis caused by Staphylococcus aureus is a disease of major economic importance to the dairy industry. Transmission occurs during milking, with chronically-infected cows acting as the major reservoirs of infection. PCR-coagulase gene typing of 151 S. aureus isolates from seven farms generated only six PCR types, with 110 (73%) isolates assigned to PCR type 1 and 23 (15.2%) isolates assigned to type 2. PCR type 1 was the predominant type on five of the seven farms, including farms in geographically separated regions of Victoria, while type 2 predominated on two farms. With the exception of the 41 isolates from one farm, all isolates were resistant to penicillin, but susceptible to other antibiotics that are routinely used to manage mastitis in dairy cattle. Nine of 11 cows with chronic S. aureus infection showed evidence of persistence of a single PCR type for periods of up to 9 months. Two different PCR types of S. aureus were isolated from the other two cows over the same period.  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