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1.
Some Cultural Characteristics of Staphylococci Isolated from Milk   总被引：2，自引：1，他引：1       下载免费PDF全文
Observations were made on the value of certain selective media for isolation and identification of staphylococci from milk obtained from individual quarters and farm bulk tanks Aerobic fermentation of mannitol salt was unreliable for identification of coagulase positive strains. Coagulase positive strains tended to clump when grown in tryptose serum broth. Tellurite glycine agar plates were not entirely reliable for the selection of coagulase positive strains. Fibrinogen-tellurite-glycine plates were very useful for the isolation of staphylococci from milk in the presence of other microorganisms and for the simultaneous identification of coagulase positive strains. Plate coagulase tests utilizing fibrinogen tellurite glycine agar corresponded almost perfectly with conventional tube tests. Fibrinolytic strains were not uncommon and were found also among beta hemolysin producing coagulase positive strains.  相似文献   

2.
A method is described for the quantitative study in vitro of the bovine milk leucocyte: staphylococci interaction which is capable of demonstrating differences between groups of leucocytes, and, to some extent, stains of Staph. aureus.

By means of this method it has been possible to show statistically, that significant differences can occur, between quarters of the same udder, in the numbers of leucocytes competent to ingest staphylococci, and also in the numbers of staphylococci ingested.

Between 4 strains of Staph. aureus significant differences were noted in their ability to multiply in the presence of milk leucocytes; in the production of leucocidal factors; and in the reduction of Resazurin in whole, normal milk.

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3.
Currently, antimicrobial-resistant staphylococci, particularly methicillin-resistant Staphylococcus pseudintermedius (MRSP), are frequently isolated from canine superficial pyoderma in Japan. However, little is known regarding the nasal prevalence of MRSP in pet dogs. Here, we determined the prevalence of antimicrobial-resistant staphylococci in nares and affected sites of pet dogs with superficial pyoderma. Of the 125 nares and 108 affected sites of pet dogs with superficial pyoderma, 107 (13 species) and 110 (eight species) staphylococci strains, respectively, were isolated. The isolation rate of S. pseudintermedius from pyoderma sites (82/110 strains, 74.5%) was significantly higher than that from nares (57/107 strains, 53.3%) (P<0.01). Notably, the prevalence of MRSP (18/57 strains, 31.6%) in nares was equivalent to that in pyoderma sites (28/82 strains, 34.1%). Furthermore, the phenotypes and genotypes of antimicrobial resistance in MRSP strains from nares were similar to those from pyoderma sites. Our findings revealed that the prevalence of antimicrobial-resistant staphylococci in the nares of pet dogs with superficial pyoderma is the same level as that in affected sites. Therefore, considerable attention should be paid to the antimicrobial resistance of commensal staphylococci in companion animals.  相似文献   

4.
One hundred and thirty-seven coagulase-positive strains of Staphylococcus aureus, isolated from dogs, were tested against three synthetic penicillins (cloxacillin, dicloxacillin, and ampicillin) and also phage typed using bacteriophages which are employed in typing staphylococci isolated from man.  相似文献   

5.
Drug Resistance Among Pathogenic Bacteria from Animals in Ontario   总被引：1，自引：1，他引：0       下载免费PDF全文
Prevalence of antimicrobial drug resistance among over 3000 clinical isolates of animal pathogens in Ontario during 1971-72 has been studied. A high number of multiple resistance patterns is prevalent among members of Enterobacteriaceae, especially Escherichia coli and Salmonella typhimurium. The most common resistance pattern among bovine strains was against not less than six drugs in common use. Among different animal species the bovine population was found to be the source of a high percentage of chloramphenicol resistant E. coli and S. typhimurium organisms. All the isolates resistant to this drug were in addition resistant to three or more other antibiotics of established therapeutic value. All the multiple resistant isolates of S. typhimurium tested had R factors and they transferred most of the resistance determinants including that for chloramphenicol to a recipient E. coli in vitro.

Penicillin resistance among Staphylococcus aureus of bovine mammary origin did not appear to be high. Antimicrobial drug susceptibility patterns of staphylococci, streptococci and Corynebacterium sp indicate effective in vitro activity with many antimicrobial agents.

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6.
Using a replica-plating method and differential culture media, members of the Enterobacteriaceae and Pseudomonaceae were determined quantitatively in the colon and cecum content of pigs from different litters, born on the same farm and kept under the same environmental conditions, from the age of six weeks. The bacterial flora in pigs of eight, ten and 12 weeks of age showed little significant quantitative variation. Pigs of 12 weeks of age differed significantly from younger ones with respect to Aeromonas, Edwardsiella, staphylococci and molds. The existence of a variable flora is underlined as well as the fact that Vibrio coli represents an important member of the intestinal flora at that age. No significant variation in the pH of the chyme of the colon and cecum was recorded.  相似文献   

7.
调查北京地区7个奶牛场奶牛流产的发病原因,采集流产胎儿及恶露不尽母牛的阴道分泌物进行细菌分离鉴定、致病性及中西药的药敏试验,并测定中药的MIC和MBC。共分离出9种42株细菌,其中金黄色葡萄球菌11株、腐生葡萄球菌6株、表皮葡萄球菌2株、变形菌属5株、克雷伯氏菌属3株、埃希氏菌属2株、蜡样菌属3株、黏液奈瑟氏菌属4株、浅黄奈瑟氏菌属2株、其他未鉴定出种属的菌4株;其中,葡萄球菌占45.2%、杆菌占23.8%、其他革兰氏阴性菌占31.0%。通过致病性试验,有28株为致病菌。对其中几种分离菌进行了25种常用抗生素、7种中药及一个复方的体外抑菌试验,结果表明,这些菌对多数抗生素有耐药性,如青霉素和链霉素,大多数革兰氏阴性菌对喹诺酮类药物比较敏感,头孢菌素类药物则对革兰氏阳性菌有较好的抑制效果,中药金银花和瓜蒌对这些菌的体外抑菌作用较好。  相似文献   

8.
The results of mastitis bacteriology made by the National Veterinary and Food Research Institute in Finland during the past 50 years (1.15 million samples) are viewed in relation to simultaneous changes in dairy cow management. Although intensive preventive measures have been applied for decades, the prevalence of bovine mastitis has not decreased. Instead, pathogenic bacteria are becoming progressively less susceptible to the available therapy. In part this must be due to the emergence of antibiotic resistant strains of bacteria, but it seems that the bacterial spectrum has also changed. The incidence of Streptococcus agalactiae (group B streptococci) has decreased, while in contrast, the incidence of staphylococci, initially Staphylococcus aureus and later coagulase-negative staphylococci, has increased. Results suggest that external pressure, like changes in animal husbandry, including antimicrobial treatments and introduction of modern milking machines, act as selective forces on the bacterial species which cause bovine mastitis.  相似文献   

9.
Swine infected experimentally with group E Streptococcus (GES) produced significant antibody titers against streptokinase (streptococcal fibrinolysin, SK) and streptodornase (streptococcal deoxyribonuclease, SD). The antibodies directed against SK (antistreptokinase, ASK) appeared two to nine weeks postexposure and persisted for the duration of the experiment (nearly six months). The ASK inhibited SK produced by GES antigenic types III, IV, and V, by GES devoid of type specific antigen, and by a group P Streptococcus. Selected strains of GES serotypes I and II and group U Streptococcus did not produce detectable SK.

The antibodies directed against SD (antistreptodornase, ASD) appeared two to three weeks postexposure, reached a peak about six weeks postexposure, and persisted at high levels for nearly six months (the duration of the experiment). The ASD inhibited SD produced by all known antigenic types of GES, by GES devoid of type specific antigen, and by strains of groups P and U Streptococcus. The antibodies failed to inhibit SD produced by group C Streptococcus.

The potential utilization of ASK and ASD titers as serological means of identifying swine infected with GES (carrier swine) is discussed.

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10.
The pathogenicity of V. coli for conventional swine was studied by inoculating pigs with cultures of V. coli and V. coli infected gut of gnotobiotic pigs. Thus, six conventional pigs were inoculated with strains of V. coli freshly isolated from infected gnotobiotic pigs. The cultures were grown in simulated sows milk, and added to the feed. Two other groups, of three pigs each, were infected by administration of minced intestine from two gnotobiotic pigs, heavily infected with the organism. Vibrio was isolated from all pigs, including five of the six controls, but larger numbers were isolated from the inoculated groups, especially from those fed macerated gut. Clinical signs of disease were not observed.  相似文献   

11.
A Comparison of Various Haemophilus somnus Strains   总被引：18，自引：5，他引：13       下载免费PDF全文
Sixty-eight Haemophilus somnus strains isolated from the bovine in Canada and the U.S.A. were compared. In media enriched with 5% ovine serum, 5% bovine serum and 10% yeast extract, H. somnus fermented glucose, levulose, maltose, mannitol, mannose, sorbitol, trehalose and xylose, but failed to ferment arabinose, dulcitol, galactose, inositol, lactose, raffinose, rhamnose, salicin and sucrose. The organisms acidified litmus milk, produced cytochrome oxidase, indole and hydrogen sulfide (H2S) and reduced nitrates to nitrites. The motility, methyl-red, acetylmethyl-carbinol urease catalase, citrate, malonate, lysine, ornithine and arginine tests were negative. Haemophilus somnus was resistant to lincomycin, neomycin and triple sulfa, but susceptible to ampicillin, chloramphenicol, streptomycin, penicillin and tetracycline. No antigenic differences were noted between strains when tested against rabbit antisera of eight strains using agglutination, complement-fixation, immunodiffusion and counterimmunoelectrophoresis tests. Low titre cross-reactions were found in the agglutination tests with some of the anti-H. somnus rabbit sera with Actinobacillus lignieresi and Moraxella bovis. No distinct antigenic similarities to nine other species of pathogenic bacteria of animal origin were found. No difference was observed between H. somnus isolates from Ontario and those from western Canada and the U.S.A.  相似文献   

12.
The gene content of 14 strains of the intestinal spirochaete Brachyspira hyodysenteriae was compared using a DNA microarray. A consistent difference occurred in a block of four genes on the ~36 Kb plasmid, with these being present in six virulent strains and absent in eight strains with reduced pathogenic potential. These genes encoded a predicted radical S-adenosylmethionine domain protein, a glycosyl transferase group 1-like protein, an NAD dependant epimerase and a dTDP-4-dehydrorhamnose 2–5 epimerase: they may be involved in rhamnose biosynthesis and glycosylation. The absence of these plasmid genes in B. hyodysenteriae isolates is predictive of reduced pathogenic potential.  相似文献   

13.
The prevalence of strains of Staphylococcus aureus, coagulase‐negative (CN) staphylococci, Listeria monocytogenes, Escherichia coli, Enterococcus faecalis, E. faecium and Bacillus cereus, was investigated in 111 bulk milk samples. Staphylococcus aureus was isolated from 38 samples, CN staphylococci from 63 samples, E. coli from 49 samples, E. faecalis or E. faecium from 107 samples, and L. monocytogenes from two samples. Bacillus cereus was not found in any of the samples and three samples were free of any of the selected species. Sensitivity to the anti‐microbial drugs amikacin, ampicillin, ampicillin + sulbactam, cephalothin (CLT), cephotaxime, clindamycin, chloramphenicol (CMP), co‐trimoxazole, erythromycin (ERY), gentamicin, neomycin, norfloxacin, oxacillin, penicillin, streptomycin (STR), tetracycline (TTC) and vancomycin was tested using the standard dilution technique. Minimum inhibitory concentration (MIC) characteristics (MIC50, MIC90, MIC range) were determined for each microbial species. Resistance against one or more anti‐microbial drugs was found in 93% of S. aureus, 40% of CN staphylococci, 73% of E. coli, 88% of E. faecalis, 55% of E. faecium, and one L. monocytogenes strain. Most of the strains, particularly enterococci, were resistant to STR, TTC, and ERY (MIC50 4 μg/ml). A high percentage of staphylococci were resistant to β‐lactam antibiotics. High resistance to CLT was found in 11 strains of E. coli (MIC 256 μg/ml) and strains resistant to CMP (MIC90 16 μg/ml) were detected. The highest numbers of resistance phenotypes were found in E. coli (16) and CN staphylococci (12). Eighteen identical resistance phenotypes were demonstrated in indicator bacteria (E. coli, E. faecalis, E. faecium) and pathogens (S. aureus, CN staphylococci) isolated from the same bulk milk sample. The obtained resistance data were matched against the herd owners' information on therapeutic use of the drugs. This confrontation could not explain the findings of strains resistant to ERY or CMP. Our findings are evidence of selection of resistant strains among not only pathogenic agents, but also among indicator bacteria which can become significant carriers of transmissible resistance genes.  相似文献   

14.
Trueperella pyogenes can be found as a commensal or pathogenic bacterium among animals causing a variety of pyogenic infections in several species. The agent appears to act primarily as an opportunistic pathogen but may disseminate and produce metastatic abscesses accompanied or not by mastitis, metritis or pneumonia. In this study, 30 porcine T. pyogenes strains were identified by MALDI-TOF MS and 16S rRNA sequencing and further evaluated in relation to their resistance and genetic profiles through broth microdilution and single enzyme AFLP. All strains were susceptible to β-lactams, florfenicol, gentamicin, spectinomycin and tiamulin. The highest resistance rates were observed for sulfonamides, tetracyclines and clindamycin. All isolates could be characterized by SE-AFLP presenting more than 80% of similarity, despite their distinct origins. Four genotypes were detected with the segregation of T. pyogenes ATCC 19411 from Brazilian T. pyogenes strains. No correlation between genotypes and isolates origins and susceptibility profile was observed.  相似文献   

15.
《Veterinary microbiology》2015,175(2-4):312-318
Salmonella enterica subsp. enterica serovar Infantis strains were isolated from broiler chickens from six farms in Japan and the pathogenicity associated with the recently reported 280 kbp mega plasmid was examined by possession of the plasmid and histopathology of tissues from these chickens. S. Infantis strains were isolated from 10 of 24 chickens. Phylogenetic, network and Bayesian cluster analyses were used to determine whether these strains were in the previously defined Clusters 1–5. Phylogenetic analysis classified the strains isolated in this study in two groups (Groups A and B). Both groups contained strains from gastrointestional contents, but only Group A also contained strains from spleen, liver, and lymphoid tissues. Histopathology showed suppurative splenitis in a spleen from which Group A strains were isolated. Although network and Bayesian cluster analyses were unable to differentiate Group A and B strains from the previously defined Clusters 1–5, population genetic analysis indicated that Group A was a different population from Cluster 5, indicating that Group A would be a subpopulation of Cluster 5. The irp2 gene, which is in the mega plasmid carried by a pathogenic S. Infantis strain recently isolated in Israel, was found in both Groups A and B strains and in the previously reported Clusters 4 and 5 strains. These results suggested that Group A would be a novel subpopulation of the previously defined Cluster 5, and presence of the mega plasmid may not be related whether S. Infantis strains can infect certain organs.  相似文献   

16.
The serological and histopathological responses of bovine fetuses to in utero inoculation with virulent and attenuated strains of the calf rotavirus (reovirus-like agent of neonatal calf diarrhea) are described. Thirteen bovine fetuses, 63 to 190 days of gestation, were inoculated in utero with attenuated (three fetuses) or field strain virus (nine fetuses) or both (one fetus).

Serum-neutralizing antibody titers ranging from 1:16 to > 1:256 were detected in six of eight fetuses tested, demonstrating the ability of the bovine fetus to respond immunologically to this agent. The youngest fetus in the series was inoculated at 63 days of gestation and developed a titer of 128 in 64 days. This represents the earliest stage of gestation at which a bovine fetus has been inoculated with a bovine virus and found to produce antibody to it. Serum neutralizing titers in six of the eight dams tested increased significantly following the inoculations of their fetuses in utero.

Histological changes associated with viral replication and antigenic stimulation of the lymphoreticular system were observed. Pneumonic lesions consisting of both local and diffuse lymphoreticular proliferation were present in five of the nine fetuses that were alive at slaughter. Gliosis and perivascular cuffing were noted in the brains of two of these fetuses and meningitis was seen in one. No evidence of teratogenic change was found.

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17.
Infection of udder halves by coagulase-negative staphylococci in seven commercial goat herds was studied in conjunction with the California Mastitis Test (CMT). Nine different species were identified and only 10% of strains belonged to groups which could not be identified with any of the known Staphylococcus species. The most prevalent species were Staphylococcus epidermidis (47.7%) and Staphylococcus caprae (19.7%). About half od the coagulase-negative staphylococcal infections gave negative CMT scores. The score was independent of the species of staphylococci involved and the stage of lactation. About 60% of the coagulase-negative staphylococcal species isolated were reisolated in the identical half udder during the following lactation.  相似文献   

18.
The enteritis complex in domestic rabbits: A field study   总被引：2，自引：0，他引：2  
A study of the causative agents of enteritis in domestic rabbits from 44 different accessions is described. In descending order of frequency, the organisms most commonly demonstrated were intestinal and hepatic coccidia (Eimeria species), Escherichia coli, Clostridium spp., Salmonella, Bacillus piliformis, and rotavirus. The species of Eimeria identified included those moderately pathogenic and coccidia of low pathogenicity. Using seven antisera against known enterpathogenic strains of E. coli, only one strain, O15, was identified in three cases. Clostridium perfringens or C. spiroforme was demonstrated in the intestinal contents in 11 cases, and lesions compatible with clostridial enteropathy were identified on gross and histopathology. In a serological survey, over 50% of 200 fryer rabbits submitted to Ontario abattoirs and of animals from commercial rabbitries had detectable antibody to rotavirus, indicating the widespread distribution of rotaviral infections in this species. In the cases of enteritis studied, two or more potentially pathogenic organisms were frequently identified, emphasizing that several different organisms may be acting in concert to produce clinical disease.  相似文献   

19.
A multiplex PCR method for rapid and sensitive diagnosis, differentiating three pathogenic Yersinia groups such as the highly pathogenic Y. enterocolitica, including serotype O8, low pathogenic Y. enterocolitica, and Y. pseudotuberculosis, was developed. Four primer pairs were chosen to detect the genes fyuA, ail, inv, and virF, responsible for the virulence in pathogenic Yersinia species. Under the multiplex PCR conditions, the unique band patterns for the highly pathogenic Y. enterocolitica, low pathogenic Y. enterocolitica, and Y. pseudotuberculosis were generated from Yersinia strains. The detection limit of this method was 101–103 CFU per reaction tube. This multiplex PCR method could detect highly pathogenic Y. enterocolitica O8 from the wild rodent fecal samples that were culture-positive. Therefore, the new multiplex PCR method developed in this study is a useful tool for rapid and sensitive diagnosis, distinguishing three pathogenic Yersinia groups.  相似文献   

20.
On four occasions leukocytes were obtained from mammary secretions of four cows following irritation by sterile distilled water.

The effects of three levels of bovine immune serum, three levels of glucose, and combinations of these on the ability of the leukocytes to ingest staphylococci in vitro were studied. Phagocytosis was estimated by examination of stained slides prepared after four hours contact at 37°C.

While 1% immune serum increased the percentage of milk leukocytes ingesting staphylococci, no improvement resulted from the addition of 3% or 5%. Addition of 20mg% glucose produced a larger increase than did 1% serum, and 40 and 60mg% gave further increases. Little advantage was obtained by combining serum and glucose at any of the levels studied.

Overall significant differences were found in the ability to ingest staphylococci by milk leukocytes from the four cows, and the previous observation that cells from some cows in vitro do not respond fully to added serum and glucose was confirmed. Neither of these phenomena was related to glycogen levels in blood or milk leukocytes as determined by the anthrone method, blood glucose levels, leukocyte viability, relative proportions of PMN's in circulating blood white cells, nor the amount of homologous blood serum in the mammary secretions. In two cows whose milk cells did not respond fully, very few blood PMN's were active.

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