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1.
Electron microscopy revealed pili on all isolates of Bordetella avium and B. avium-like bacteria examined. Trypticase soy broth (TSB) and 2% peptone agar were the best media for promoting pilus expression. Cultures grown at 37 or 42 C had similar pilus production, whereas cultures grown at 18 C produced few or no pili. Pilus expression of the Art Vax strain was best when that strain was grown in TSB, but the strain yielded fewer pili than B. avium and B. avium-like isolates grown under the same cultural conditions. B. avium pili had a diameter of 2.0 nm, ranged in length from 370 nm to 1500 nm, and had a protein subunit molecular mass of about 13,100 daltons. Purified pili from B. avium did not hemagglutinate guinea pig erythrocytes, and a 1:20 dilution of hyperimmune antisera against B. avium pili did not block the hemagglutinating activity of whole-cell preparations of B. avium. In the indirect immunofluorescence test, B. avium isolates and the Art Vax strain adhered to the tracheal explants of turkeys, but B. avium-like isolates did not. Purified pili from B. avium adhered to the surface of the mucosal lining of the tracheal explants, and hyperimmune antisera against B. avium pili blocked the in vitro adherence of whole-cell preparations of B. avium. It was concluded that pili of B. avium are involved in the in vitro attachment of that bacterium to the mucosal surface of turkey tracheal explants.  相似文献   

2.
The rate and amount of growth of 4 field isolates and reference strain ATCC 6223 of Francisella tularensis were evaluated on isolation media with 2 different agar bases and with different supplements and incubated at 25 C, 35 C, and 42 C. Biochemical reactions on conventional differential media with and without cysteine were evaluated. Two of the field isolates and the reference strain were F. tularensis subspecies tularensis (formerly biovar tularensis or Type A), and 2 isolates were subspecies holarctica (formerly subspecies palaearctica or Type B). Bacto cystine heart blood agar supplemented with 1% hemoglobin, glucose cystine heart blood agar, and brain-heart infusion blood agar supported good growth of all 4 field strains, with the most luxuriant growth occurring on Bacto cystine heart blood agar with hemoglobin. Heart infusion blood agar and trypticase soy blood agar supported growth of the field isolates, although growth was diminished and delayed. Strain 6223 was distinctly fastidious and failed to grow on heart infusion or trypticase soy blood agars. Growth of strain 6223 was best on Bacto cystine heart blood agar with hemoglobin. The agar base did not affect growth unless the supplements became limiting, in which case Bacto agar base generally supported growth better than BiTek agar base. Incubation at 35 C was optimum for all 5 strains. Growth at 42 C was slow, with the greatest decrease in the rate and amount of growth occurring with field isolates of F. tularensis subspecies tularensis. Strain 6223 did not grow at 25 C, and the 4 field isolates grew slowly at the lower temperature.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
Cellular, colonial, cultural, and biochemical characteristics of 25 field strains of gram-negative pleomorphic bacilli from rams with epididymitis were compared with Actinobacillus actinomycetemcomitans American Type Culture Collection (ATCC) strain 29522 and Actinobacillus seminis ATCC strain 15768. Three field strains were identified as A. actinomycetemcomitans, 15 as A. seminis, and 2 as Haemophilus agni; however, 5 strains (3 in group A and 2 in group B) were not identified as species in the genera Actinobacillus, Haemophilus, or Pasteurella based on the taxonomic criteria in Bergey's manual of systematic bacteriology. The 5 Actinobacillus-like organisms in groups A and B were predominantly gram-negative coccobacilli and exhibited less pleomorphism than the 2 Actinobacillus species. The colonial morphologies of groups A and B were similar to the 2 Actinobacillus species but were smaller in diameter and had a pale yellow color. Groups A and B, like the actinobacilli, were facultative anaerobic and capnophilic, did not grow on MacConkey agar, and were catalase-positive and oxidase-positive. Group A reduced nitrate but group B did not. The A. seminis strains utilized ornithine, and group A utilized arginine; but group B did not utilize either ornithine or arginine. All strains failed to utilize lysine or tryptophane. All strains produced acid but no gas from glucose, and the utilization of other carbohydrates varied markedly both between and within the 5 groups of bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

4.
The prevalence of human pathogenic Yersinia enterocolitica isolates in livestock farming is of paramount interest. Raw goat milk has been proposed as a source of human yersiniosis; however, no data on the prevalence of human strains of Y. enterocolitica in goat herds are available. Therefore, fecal samples (n = 575) were collected from 24 goat herds from Lower Saxony, northern Germany. Pre-enrichment in peptone, sorbitol and bile salts broth was followed by plating on cefsuloidin irgasan novobiocin agar. Yersinia enterocolitica was isolated from 17 (3%) samples of five (21%) goat herds. All isolates were biovar 1A, but represented various serovars. PCR assays targeting Yersinia adhesin (yad) gene and the yopT gene, both associated with pathogenicity, produced no amplification products. Therefore, the isolates can be regarded as opportunistic apathogenic bacteria. Consequently, milk, cheese or meat from goats should not be considered as an important source for human yersiniosis.  相似文献   

5.
Abstract

Proteases of 23 isolates of Flavobacterium columnare derived primarily from channel catfish Ictalurus punctatus raised in the southeastern United States were isolated and partially characterized. The bacterial isolates were divided into two groups according to the apparent molecular masses of proteases after zymographic resolution by nonreducing, nondenaturing sodium dodccyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) with gelatin as the protease substrate. The 15 isolates in group 1 had two proteases with apparent molecular masses of 58 and 53.5 kilodaltons (kDa). Eight group-2 isolates produced three proteases with apparent molecular masses of 59.5, 48, and 44.5 kDa. Culture medium had an effect on the amount of protease produced by F. columnare LA 88–173. More protease was produced in a medium with low nutrients and salt (Ordal's medium) than in media with higher concentrations of nutrients or salts (TYES, Hsu-Shotts, modified Shieh's media). No differences were observed in the apparent molecular masses of the two proteases of F. columnare LA 88–173 produced in the various media or with different incubation times. Two proteases with apparent molecular masses of 58 and 53.5 kDa were seen as early as I d after inoculation, and these molecular masses did not change during the 7-d experiment. A sharp increase in protease production occurred during the first 24 h of incubation with minimal increase during the remaining 7 d of the experiment. All 23 isolates of F. columnare degraded the gelatin and casein incorporated into TYES agar medium but only 7 of the 23 isolates degraded elastin.  相似文献   

6.
Brucella suis biovar 2 is the most common aetiological agent of porcine brucellosis in Europe. B. suis biovar 2 is considered to have low zoonotic potential, but is a causative agent of reproductive losses in pigs, and it is thus economically important. The multilocus variable-number of tandem repeats genotyping analysis of 16 loci (MLVA-16) has proven to be highly discriminatory and is the most suitable assay for simultaneously identifying B. suis and tracking infections. The aim of this study was to investigate the relatedness between isolates of B. suis biovar 2 obtained during a brucellosis outbreak in domestic pigs and isolates from wild boars and hares collected from proximal or remote geographical areas by MLVA-16. A cluster analysis of the MLVA-16 data revealed that most of the isolates obtained from Switzerland clustered together, with the exception of one isolate. The outbreak isolates constituted a unique subcluster (with a genetic similarity >93.8%) distinct from that of the isolates obtained from wild animals, suggesting that direct transmission of the bacterium from wild boars to domestic pigs did not occur in this outbreak. To obtain a representative number of isolates for MLVA-16, alternative methods of Brucella spp. isolation from tissue samples were compared with conventional direct cultivation on a Brucella-selective agar. We observed an enhanced sensitivity when mechanical homogenisation was followed by host cell lysis prior to cultivation on the Brucella-selective agar. This work demonstrates that MLVA-16 is an excellent tool for both monitoring brucellosis and investigating outbreaks. Additionally, we present efficient alternatives for the isolation of Brucella spp.  相似文献   

7.
Ten nutritionally variant streptococci were recovered from clinical specimens submitted to the Kansas State University Veterinary Clinical Bacteriology laboratory over a 4-year period. Isolates were recognized visually on primary blood agar plates by their satellite growth around a previously overlaid Staphylococcus aureus culture. All isolates grew within 24 hours in Todd-Hewitt and heart infusion broths supplemented with 5% bovine fetal serum and 5% S aureus filtrate. They also grew anaerobically in supplemented broths within 48 hours. However, isolates did not grow aerobically or anaerobically in the absence of supplements up to a 7-day postinoculation period. As determined by the standard Kirby-Bauer technique, the isolates were highly susceptible to antimicrobial agents commonly recommended in veterinary medicine. The isolates did not react with the corresponding Lancefield group-specific antisera, as tested by the capillary precipitin test.  相似文献   

8.
Four hundred twenty-nine isolates of Escherichia coli from calves were tested for the production of HeLa cell cytotoxin(s). Isolates that produced enough cytotoxin to be detected in culture supernatants of iron-depleted broth were considered to produce increased amounts of cytotoxins. Isolates also were tested for homology with a DNA probe for a gene that encodes localized adherence of human enteropathogenic E coli. Four isolates produced increased amounts of cytotoxin that was neutralized by Shiga antitoxin (toxin designated as Shiga-like toxin-I [SLT-I]). A 5th isolate produced increased amounts of cytotoxin (SLT+) that was not neutralized by the Shiga antitoxin, but was neutralized by antitoxin against a variant of SLT (toxin designated as SLT-II). None of the isolates hybridized with the probe for the localized adherence gene. Three of the SLT+ isolates belonged to human enteropathogenic E coli serogroups O26 and O111. All 5 of the SLT+ isolates were from calves with diarrhea, but none of the 5 SLT+ isolates contained genes for classic heat-labile or heat-stable enterotoxins, for K99 fimbriae, or for invasiveness; neither did any of them adhere to HeLa cells in culture. Three of the 5 SLT+ isolates had attaching and effacing activities when inoculated into ligated intestinal loops of rabbits. One of the isolates with attaching and effacing activity in rabbits was originally isolated from a calf with lesions characteristic of those produced by attaching effacing E coli (AEEC). Calves inoculated with this SLT+ AEEC isolate developed focal colonic lesions characteristic of those produced by AEEC, but did not develop diarrhea.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

9.
Sixty-one isolates of Fusobacterium necrophorum were recovered for study. Thirty-one were obtained from lesions of foot abscess in cattle (25) and sheep (6), 28 were from interdigital lesions in cattle and 2 were from the normal interdigital skin of cattle. The majority of isolates from lesions of foot abscess were virulent, belonged to biotype AB (Fievez 1963), produced flat, irregular shaped, greyish colonies and haemolysis on blood agar, and grew as turbid filamentous suspensions in liquid media. They produced a soluble exotoxin, a leucocidin, and were pathogenic for cattle and mice. Virulent isolates also produced a haemolysin which most readily lysed bovine, equine and chicken erythrocytes; those from sheep were less susceptible while those of rabbit and pig were the most resistant. Isolates recovered from lesions of the feet not classified as foot abscess and from clinically normal feet were predominantly of the B biotype and caused few experimental lesions, produced convex, round, yellow colonies, flocculated and sedimented while growing in liquid medium and produced little or no haemolysin or leucocidin. Routine differentiation between virulent and non-virulent bovine isolates of F. necrophorum could be achieved by assessing the colour, morphology, and degree of haemolytic activity of colonies grown on blood agar.  相似文献   

10.
Rotaviruses were isolated on BSC-1 cells from counterimmunoelectrophoresis and/or electron microscopy positive intestinal contents from two asymptomatic and six diarrheic calves from Quebec. The plaque assay was performed using these lines and agar overlay medium containing trypsin and DEAE-dextran. This assay was used to compare the Quebec isolates to an attenuated American strain (NCDV) and another strain (TH) obtained from France. The NCDV strain produced plaques that were significantly larger than those produced by the TH strain. Three Quebec isolates produced plaques similar in size to TH strain, one isolate was similar to NCDV strain and another isolate produced larger plaques than those of both NCDV and TH strains. The other isolates induced the production of plaques that were not significantly different from those of NCDV or TH strains.  相似文献   

11.
In this study, Staphylococcus aureus strains (n = 110) isolated from seven ewe flocks in Sanliurfa, Turkey were screened for antibiotic resistance and biofilmforming ability as well as for genes associated with antibiotic resistance and biofilm-forming ability. All isolates were found to be susceptible to oxacillin, gentamicin, clindamycin, cefoxitin, tetracycline, vancomycin, amoxicillin-clavulanic acid, ciprofloxacin and sulphamethoxazole-trimethoprim. The percent proportions of strains resistant to penicillin G, ampicillin and erythromycin were 27.2% (n = 30), 25.4% (n = 28) and 6.3% (n = 7), respectively. Regarding the antibiotic resistance genes, 32 (29%) isolates carried the blaZ and 8 (7.2%) the ermC gene. Other resistance genes were not detected in the isolates. All isolates showed biofilm-forming ability on Congo red agar (CRA), while 108 (98.18%) and 101 (91.81%) of them were identified as biofilm producers by the use of standard tube (ST) and microplate (MP) methods, respectively. All isolates carried the icaA and icaD genes but none of them harboured the bap gene. The results demonstrated that S. aureus isolates from gangrenous mastitis were mainly resistant to penicillins (which are susceptible to the staphylococcal beta-lactamase enzyme), and less frequently to erythromycin. Furthermore, all of the S. aureus isolates produced biofilm which was considered a potential virulence factor in the pathogenesis of staphylococcal mastitis.  相似文献   

12.
OBJECTIVE: To identify swimming motility in Salmonella pullorum isolates and to characterize the flagellar proteins produced by motile isolates. SAMPLE POPULATION: 30 S pullorum isolates and isolates of 7 other Salmonella sp. PROCEDURE: Salmonella pullorum isolates were inoculated into high motility medium to evaluate swimming motility. Putative flagellar proteins were purified from the organisms and analyzed by means of gel electrophoresis and western blotting procedures, using various antisera specific for flagellar proteins. Antisera shown to be reactive with putative flagellar proteins were incorporated into the growth medium to examine their effects on motility of the isolates. RESULTS: All S pullorum isolates had evidence of swimming motility. Two putative flagellar proteins were purified from 2 of the S pullorum isolates: a 60 to 62 kd protein shown to react with antiserum specific for type y flagellar protein, and a 58 to 59 kd protein shown to react with antiserum specific for type d flagellar protein and with antibody reactive to a highly conserved flagellar epitope found on various Enterobacteriaceae. Antiserum specific for type d flagellar protein inhibited swimming motility of S pullorum isolates, but antiserum specific for type y flagellar protein did not. CONCLUSIONS: Results suggest that S pullorum isolates can be induced to manifest swimming motility when grown on medium with a low agar concentration and possess a 58 to 59 kd protein of d serotype and a second protein of 60 to 62 kd that also may be a flagellar protein.  相似文献   

13.
Further characterization of the agent causing coryza in turkeys   总被引：9，自引：0，他引：9  
A total of 128 isolates of Alcaligenes faecalis, from the respiratory tract of turkeys and chickens, were identified and divided into two types designated type I and type II. Type I isolates were pathogenic in poults, hemagglutinated guinea pig red blood cells (RBCs), and did not grow on minimal essential medium (MEM) agar, and most did not grow in 6.5% NaCl broth. Type II isolates were nonpathogenic and nonhemagglutinating and grew on MEM agar, and most grew in 6.5% NaCl broth. Hemagglutination of guinea pig RBCs was a reliable characteristic for distinguishing type I from type II isolates, and it correlated with pathogenicity. In serological studies using 62 type I and 21 type II isolates, cross-reactions were observed when type I but not type II antigens were used to test antisera in the microagglutination test. Eleven bacterial isolates, different from type I and type II isolates, were urease-positive. Although frequently isolated from turkeys with coryza, these isolates were nonpathogenic and were always found in association with type I A. faecalis. Urease-positive isolates and type I and type II A. faecalis isolates were stable following 50 in vitro passages. Bordetella avium sp. nov. (the nomenclature suggested in Europe for A. faecalis) was pathogenic in poults. The colonial morphology, biochemical characteristics, and hemagglutinating activity of B. avium sp. nov. were the same as those of type I A. faecalis isolates. Based on the results of these studies, it was concluded that type I A. faecalis is the etiologic agent of turkey coryza.  相似文献   

14.
Prevalence and characterization of Staphylococcus aureus in young goats   总被引：2，自引：0，他引：2  
Thirty-six Staphylococcus aureus isolates recovered from 35 of 204 young goats at slaughter were characterized. All isolates were susceptible to cephalothin, clindamycin, chloramphenicol, gentamicin, kanamycin, and amikacin. All but 2 were susceptible to erythromycin and tetracycline, and 19 and 20 were susceptible to penicillin and ampicillin, respectively. Thirteen isolates were classified as biotype A, 9 isolates were classified as biotype B, 8 isolates were classified as biotype C, and 6 isolates were classified as intermediate between B and C or were not biotypable. Six biotype A isolates were enterotoxigenic; 4 produced enterotoxin B, 1 produced enterotoxin C, and 1 produced enterotoxin D. Two biotype B strains produced enterotoxin B, and all 8 biotype C isolates produced enterotoxin C and the toxic shock syndrome toxin-1.  相似文献   

15.
The in vitro susceptibilities of six commonly used antimicrobial agents against 29 isolates of intestinal spirochetes isolated from dogs in Japan were examined by the agar dilution technique. In addition, the genetic basis of tylosin resistance in in vitro selected resistant mutants of two reference strains and three tylosin-susceptible field isolates obtained by three successive subcultures on blood agar containing 1 microg/ml of tylosin was investigated. Carbadox was the most active (MIC: < 0.00625) of all the antimicrobial agents. Although all the isolates were susceptible to tylosin, some were resistant to erythromycin. Tiamulin, lincomycin and dimetridazole were also very active against the isolates. All the resistant isolates did not harbor any plasmids. In vitro selected tylosin-resistant mutants of previously tylosin-susceptible isolates showed a new mutation in which their adenine at the base position equivalent to 2062 of 23S rDNA of Escherichia coli has been replaced by cytosine. These findings may both provide guidance towards the proper choice of antimicrobial agents for the treatment of canine intestinal spirochetosis, and add to the understanding of the genetic basis of tylosin resistance.  相似文献   

16.
为确定云南省不同地区3个猪场仔猪发生四肢运动障碍的病原因素,无菌采集病死仔猪内部组织样品,采用血琼脂分离培养病原菌,随后对分离菌株做形态观察、生化试验、药敏试验及16S rRNA基因测序分析。结果：从3个猪场病料中均分离到菌落及个体形态一致的细菌,其16S rRNA基因序列与NCBI中7株绿色气球菌参考菌株的同源性均在99%以上,据此判定为绿色气球菌(Aerococcus viridans);3个分离菌株均对克拉霉素、头孢曲松和青霉素敏感,对复方新诺明、庆大霉素和卡那霉素耐药。鉴于病死猪有检出其他病原体感染的情况和未见该菌单独有强致病力的报道,研究结果提示绿色气球菌是危害猪健康养殖的重要机会致病菌。  相似文献   

17.
Selective medium for isolation of Haemophilus somnus from cattle and sheep   总被引：6，自引：0，他引：6  
Incorporation of vancomycin (5 micrograms/ml), neomycin (5 micrograms/ml), sodium azide (50 micrograms/ml), nystatin (100 iu/ml) and cyclohexamide (100 micrograms/ml) into 5 per cent horse blood agar results in a selective medium for the primary isolation of Haemophilus somnus from cattle and sheep. Addition of thiamine monophosphate (1 microgram/ml) to the medium enhanced growth of this bacterium. Gram-positive bacteria did not grow on the medium and colonies of many Gram-negative bacteria were eliminated or reduced in numbers and size. Colonies of H somnus were larger on the selective medium than on sheep blood agar but retained typical morphology. Recovery of 18 laboratory strains was 73 to 166 per cent (mean 112) on selective medium compared to sheep blood agar. H somnus was isolated from the vagina of a total of 136 (28.6 per cent) of 476 cows surveyed, 79 (16.6 per cent) on sheep blood agar and 129 (27.1 per cent) on selective medium. The selective agents and thiamine were stable indefinitely as a freeze dried mixture while prepared plates were stable for two weeks.  相似文献   

18.
Four strains of nutritionally variant streptococci (NVS) were isolated from the milk of mastitic cows and one strain from the lungs of a laboratory Norway rat which died from suppurative pneumonia. In primary cultivation NVS grew aerobically and anaerobically within 48-hour incubation at a temperature of 37 degrees C as minute nonhemolytic satellite colonies around a previously overlaid S. aureus strain or around other gram-positive and gram-negative bacteria. In the first subcultures NVS were growing in nutrient media enriched with 10% bovine serum and 5% staphylococcal filtrate, or 0.02% to 0.002% pyridoxal hydrochloride. All isolates did not grow in presence of 10%, 40% bile, and 6.5% of sodium chloride, neither did they grow at a temperature of 45 degrees C, they did not hydrolyze sodium hippurate, esculin, arginine, they did not produce levane and dextran from saccharose, they produced acid from mannitol, sorbitol, inulin, lactose, raffinose, trehalose, glucose, saccharose and maltose. Two strains produced acid from xylose and four strains from salicin. The strains isolated from mastitis did not have different biochemical properties from those isolated from a laboratory Norway rat with pneumonia. All strains of NVS were sensitive to chloramphenicol, ampicillin, gentamycin, lincomycin and cephalothin, four strains were sensitive to erythromycin and tyrosine, two to penicillin and one to streptomycin, oxytetracycline, chlortetracycline and novobiocin. All strains were resistant to neomycin, tetracycline, oxacillin and sulphonamides. The antigen prepared from the isolated strains by the method of Fuller did not react with any streptococcal group serum A-Z.  相似文献   

19.
A collection of 125 Salmonella enterica poultry isolates (71 serovar Kentucky isolates, and the remainder belonging to serovars Alachua, Enteritidis, Hadar, Heidelberg, Montevideo, Mbandaka, Senftenberg, Typhimurium, and Worthington) were tested for the ability to grow on tryptic soy agar containing sodium arsenite [As(III)] or arsenate [As(V)]. All serovar Kentucky isolates and 18 of the non-Kentucky isolates were able to grow in the presence of 0.1 mM As(III), and 69 grew in the presence of 1 mM As(V). Thirty of the non-Kentucky isolates did not grow at these As(III) and As(V) concentrations, but seven grew at 1 mM As(III) and 10 mM As(V). PCR-based analysis demonstrated the presence of arsB and arsD sequences in all Kentucky isolates, whereas one or both of these sequences were present in only 30 of the other isolates. It remains to be determined if these arsenic-resistance determinants benefit Salmonella exposed to man-made arsenic-containing compounds in poultry environments.  相似文献   

20.
This study is reporting an outbreak of subclinical mastitis due to beta-hemolytic group L streptococci in an Austrian dairy herd with a history of high somatic cell count. At the first survey 16 of 33 lactating cows (28 quarters of 132) were cultured positive for beta-hemolytic, CAMP and esculin negative cocci that grew on Columbia blood agar with small grey catalase negative colonies. With the commercial API 20 Strep system (bioMerieux, F) isolates were classified as members of streptococci group L. All tested strains (eight of 28) produced acid from ribose, lactose, trehalose, amidon and glycogen; they hydrolysed hippurate and showed beta-glucuronidase, beta-galactosidase, alkaline phosphatase, leucinaminopeptidase and arginindehydrolase activity. Isolates were sensitive to bacitracin but resistant to tetracycline. Using phenotypic characterisation as well as sequence analysis of the 16S-23S intergenic spacer region of a representative strain, recovered isolates were identified as Streptococcus (S.) dysgalactiae ssp. equisimilis. Mastitis was characterized by normal milk secretions and absence of clinical abnormalities but high elevations of somatic cell count. Based on the characteristics of the strains and on the observations during the first herd survey, contagious transmission during milking as a result of poor milking hygiene was assumed. The mastitis was controlled through implementation of a strict hygiene protocol including use of single-use udder towels, post milking teat desinfection and cluster disinfection between milking cows in combination with antibiotic treatment of infected udders.  相似文献   

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