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Isolation of viruses from calves with acute respiratory tract disease were attempted on bovine embryonic lung cell cultures. An isolate obtained from one calf with oral lesions and respiratory disease, designated 44-M-E482, was characterized as a paravaccinia virus on the basis of biological and physical properties. The calf from which the paravaccinia virus 44-M-E482 was isolated did not possess serum neutralizing antibody in its convalescent sera; neither did experimentally inoculated calves possess serum neutralizing antibody to the isolate. However, a low titer of serum neutralizing antibody was produced in one calf after several intravenous injections of the virus. Inoculation of calves with 44-M-E482 into the oral mucosa, skin, nasal cavity and pharynx did not cause any noticeable illness or lesions. The relation of 44-M-E482 to the viruses which cause bovine papular stomatitis and pseudocowpox is discussed. 相似文献
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Yoshimura H Ishimaru M Endoh YS Kojima A 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2001,48(7):555-560
Minimum inhibitory concentrations (MICs) of 10 antimicrobial agents were determined for Pasteurella multocida from cattle and pigs (72 and 68 isolates, respectively). Higher MICs were observed with oxytetracycline, doxycycline, tilmicosin and thiamphenicol for porcine isolates than for bovine isolates. Enrofloxacin was the most active, with an MIC for 90% of the isolates (MIC90) of 0.05 microg/ml for both bovine and porcine isolates. Aspoxicillin exhibited the same excellent activity against penicillin-susceptible isolates as ceftiofur, with MICs ranging from < or = 0.025 to 0.1 microg/ml. Aminoglycosides were less active, with an MIC90 of > 100 microg/ml for both bovine and porcine isolates. 相似文献
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Yoshimura H Kojima A Ishimaru M 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2000,47(2):139-143
The minimum inhibitory concentrations (MICs) of 18 antimicrobial agents were determined for 49 Arcanobacterium pyogenes isolates (42 bovine isolates and 7 porcine isolates). Benzylpenicillin and ampicillin were the most active antibiotics, with MIC ranges of < or = 0.0125-0.05 microgram/ml for both bovine and porcine isolates. All isolates were susceptible to penicillins and cephems. MICs for 90% of the isolates of dihydrostreptomycin, gentamicin and oxytetracycline for bovine isolates were > 100 micrograms/ml, 1.56 micrograms/ml and 25 micrograms/ml, respectively. More resistance to dihydrostreptomycin appeared among porcine isolates (85.7%) than among bovine isolates (52.4%). Resistance to gentamicin occurred in only 3 (7.1%) of the bovine isolates. Resistance to oxytetracycline also appeared more frequent among porcine isolates (85.7%) than among bovine isolates (57.1%). All bovine isolates were susceptible to erythromycin, tilmocosin and lincomycin, but two porcine isolates (28.6%) were simultaneously resistant to these antibiotics. Tiamulin was as active as tilmicosin, with an MIC for 50% of the isolates (MIC50) of 0.05 microgram/ml for both bovine and porcine isolates. The MIC50s of chloramphenicol and its derivatives florfenicol and thiamphenicol were all 1.56 micrograms/ml. The fluoroquinolones enrofloxacin and ofloxacin were not so active as penicillins and macrolides, with MIC50s of 0.78 microgram/ml and 1.56 micrograms/ml, respectively, for both bovine and porcine isolates. 相似文献
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Therapeutic effect of Berenil and Samorin in mice infected with four trypanosome populations isolated from Zambian cattle 总被引:2,自引:0,他引:2
Four populations of Trypanosoma congolense and Trypanosoma brucei brucei were isolated from cattle under different management practices and environments in Zambia. All four isolates had varied responses to both diminazene aceturate (Berenil) and isometamidium chloride (Samorin) as curative drugs in infected mice. Trypanosomes from a traditionally managed herd in a high-tsetse-challenge area had the strains most resistant to Berenil, with maximum curative dose of 45 mg kg-1 body weight. Another isolate from a high-tsetse-challenge area was evidently resistant both to Berenil at 40 mg kg-1 and to Samorin at 4 mg kg-1. The strains most susceptible to both Berenil and Samorin were from a commercially managed herd of cattle under medium tsetse challenge. They responded to recommended cattle standard doses of 3.5 mg kg-1 or 7 mg kg-1 Berenil and to as little as 0.25 mg kg-1 Samorin. It is evident that trypanosome strains resistant to Berenil and/or partially resistant to Samorin exist, and that both T. congolense and T. b. brucei are implicated. 相似文献
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Fourteen isolates of Bacteroides nodosus were cultured from cattle on six farms and examined for colony morphology, pilation, agglutinability, proteolytic activity and pathogenicity for sheep. Where sheep were also present on the farms, isolates from these were compared with those from cattle.Colonies of the bovine isolates were moderately fimbriate. Cells from these colonies were pilated, but not to the extent observed on virulent sheep isolates. The proteolytic activity of the isolates was also less than that described for virulent ovine isolates. When inoculated into sheep, B. nodosus from cattle produced only mild interdigital inflammation. There was no separation of horn characteristic of virulent foot-rot. Preliminary studies, based on agglutination tests, suggest that B. nodosus with different surface antigens may occur in cattle in the same herd and in cattle and sheep on the same farm. On one of six farms isolates from cattle and sheep were indistinguishable by the agglutination test. 相似文献
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The effects of fibrinogen on phagocytic killing of Streptococcus dysgalactiae from cattle and S. equi from horses were studied in comparison to that of S. pyogenes from humans. Phagocytic killing was determined by a fluorometric microassay using glass adherent polymorphonuclear neutrophils (PMN) from the respective host species, preopsonization with homologous sera led to a dose-dependent increase in phagocytic killing of all streptococcal cultures, preincubation of streptococci with fibrinogen significantly inhibited their phagocytic killing. Fibrinogen had no effect on phagocytic killing of non-fibrinogen binding S. agalactiae cultures. Further characterization studies with S. dysgalactiae and S. pyogenes revealed that a partial inhibition of phagocytic killing could also be achieved by preincubation with monomeric beta-chains of fibrinogen. Digestion of the fibrinogen binding sites on streptococci with proteases resulted in an almost complete loss of the inhibitory effects of fibrinogen on phagocytic killing. It could thus be concluded that by binding fibrinogen animal pathogenic streptococci could evade phagocytic killing in a similar manner as M protein carrying S. pyogenes isolates from human infections. 相似文献
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The aim of this study was to analyse a florfenicol-resistant Mannheimia haemolytica isolated from a calf to determine the genetic basis of its florfenicol-resistance. The antimicrobial susceptibility and plasmid content of the isolate were determined. A florfenicol resistant plasmid carrying the floR gene was identified by PCR and transformed into Escherichia coli JM109 and HB101 strains. The plasmid was then mapped and sequenced completely. The isolate was resistant to chloramphenicol, florfenicol, oxytetracycline, kanamycin, dihydrostreptomycin, nalidixic acid, ampicillin, and amoxicillin; it carried a floR plasmid of 7.7kb, designated pMH1405. The mobilisation and replication genes of pMH1405 showed extensive similarity to the 5.1-kb pDN1 plasmid from Dichelobacter nodosus and the 10.8-kb pCCK381 plasmid from Pasteurella multocida. An adjacent 2.4-kb segment was highly homologous to the TnfloR region of the E. coli BN10660 plasmid. A plasmid-mediated floR gene was responsible for florfenicol resistance in the bovine respiratory tract pathogen M. haemolytica. The pMH1405 plasmid is the smallest floR-carrying plasmid reported to date. To the best of our knowledge, this is the first report of a florfenicol-resistant gene in M. haemolytica. 相似文献
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To compare the genotypes of Campylobacter jejuni, isolates of cattle origin were collected from 9 Polish farms and genotyped by ERIC-PCR. We identified 28 genotypes among the 43 C. jejuni isolates, and demonstrated high genomic diversity. The highest level of diversity was observed in strains isolated from stanchion-barn animals in opposition to those from the loose-housing system. 相似文献
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