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豚由来Escherichia coliに関する研究
https://az.repo.nii.ac.jp/records/3187
https://az.repo.nii.ac.jp/records/31873b23c609-0dd8-4795-903b-83bbb95213a0
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diss_dv_otsu0057 (3.6 MB)
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diss_dv_otsu0057_jab&rev (1.0 MB)
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diss_dv_otsu0057_jab.pdf (102.0 kB)
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diss_dv_otsu0057_eab.pdf (756.4 kB)
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| Item type | 学位論文 / Thesis or Dissertation(1) | |||||||||
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| 公開日 | 2013-01-29 | |||||||||
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| タイトル | 豚由来Escherichia coliに関する研究 | |||||||||
| タイトル | ||||||||||
| タイトル | The characters of Escherichia coli of swine origin | |||||||||
| 言語 | en | |||||||||
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| 言語 | jpn | |||||||||
| 資源タイプ | ||||||||||
| 資源タイプ | thesis | |||||||||
| 著者 |
今村, 嘉礼武
× 今村, 嘉礼武
× Imamura, Karebu
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| 抄録 | ||||||||||
| 内容記述タイプ | Abstract | |||||||||
| 内容記述 | Escherichia coliの研究は1947年，Kauffmannの血清学的分類に始るといっても過言ではない。すなわち，彼の発表した25のO抗原，55のK抗原，20のH抗原が今日の血清学的抗原表の基となっている。 本菌の特性として，1)血清学的に分類可能なこと。2）病原性の強い菌株は，特定の抗原因子を有する。3)人と動物に共通して存在する菌株と相互に無関係に存在する菌株があるという事。4)多少病原性があれば，往々にして他の微生物，例えばウイルス等の感染の際に二次的に混合感染をする傾向がある。5)E. coliは炭疽菌など他種の病原菌の発育を抑制する。すなわち拮抗作用を示すものがあるといわれている。 著者はこの点を考慮し，まず子豚の下痢由来E. coliと，健康便由来E. coliを分離し，その血清学的，生化学的性状を詳細に調べ，更に健康成豚の保菌状況を調べ，由来別本菌の性状を明らかにするとともに，豚由来E. coliによる血清学的分類について検討を試みたものである。 1962年から1966年の間，と畜場において健康と認められるもの145頭と，病理学的所見のある5頭について，Mac Conkey培地を使いE. coliの分離を行い，更に1968年から1971年の間に健康子豚50頭，白痢子豚50頭についてもE. coliの分離を行い以下に述べる試験を行ったものである。 1. E. coliの分離初期と継代中のものとは，染色の態度が違うことが認められた。 2. 生化学的性状や各種炭水化物の分解態度のうち，Indol反応，Xylose，Mannitol，Litumusmilkの反応は通常陽性と言われているが，菌株により陰性もあり人由来E. coliと同様な傾向を示した。 3. 健康豚由来E. coliについて血清学的に分類した結果，気温20℃以上と以下では大腸菌抗O血清に凝集する菌株数には有意の差が認められ，また気温と血清番号は相関々係を示した。 4. 牛乳培地へE. coliを移殖し，1箇月室温に放置したあとも牛乳培地に変化を認めなかったので，E. coliの蛋白分解能をみるため，ペーパークロマトグラフィーを使い実験した結果，蛋白質の分解産物たるアミノ酸を認めなかったので，本菌は牛乳蛋白質の分解能はないものと思考される。 5. 薬剤に関する感受性は，最も感受性のあるもの，Chloramphenicol，Colistin，Kanamycin，Streptomycin，中等度は，Tetracycline，Sulfisoxazolで，感受性のないものは，Penicillin，Erythromycin，Oleandomycin，Leucomycinとなっている。 6. Disc法を使って，E. coli相互間の拮抗作用を調べたところ，溶血能のある菌株と，人由来E. coliとの間に拮抗作用のあることを認めた。 7. 特定養豚地区で多頭飼育されている子豚について，健康な便と白色下痢便とについてE. coliを検索したところ，両者に共通したO抗原を有意的に検出した。 8. Kauffmann抗O血清に凝集しない菌株については，その生化学的性状から判断し，白糖分解性の有無と運動性の有無とを組合せて，新に4種の血清を作製した。これによりKauffmann抗O血清に凝集しない豚由来E. coliは，5種の血清型に分類し得るものと認める。 以上の試験成績を考察すると次のような結論が得られる。すなわち今回の研究目標が，由来を異にするE. coliの性状を究明するとともに，健康成豚の保菌する本菌の状況をも把握し，由来による本菌の性状を究明することにあつたので今回の成績から次の3項目を記述すべきものと考える。 (1) 特定地域に飼育される子豚には，特定な血清型のE. coliが有意的に検出される。 (2) 豚由来E. coliには，抗生物質に対する多剤耐性のものが検出される。 (3) Kauffmann抗O血清に凝集しない豚由来E. coliは，5種の血清型に分れることを認める。 |
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| Abstract | ||||||||||
| 内容記述タイプ | Other | |||||||||
| 内容記述 | I. Introduction. II. The characters of Escherichia coli of different origin. III. The characters of Escherichia coli strains of healthy adult swine. IV. Newly designed serotyping of Escherichia coli of swine origin by means of antisera prepared for its representative strains of swine origin. Conclusion. I. Introduction There have been already described numerous works as to biochemical or serological classification of Escherichia coli strains which were isolated from both normal and pathological fecal contents, furthermore from organs in any ill conditions. Above all, the results of Kauffmann, Ewing, Glantz and others made us note that the characters of the bacterium were more or less different depending upon the origin of its strains. In particular, they appears to possess specificity not only biochemically but also serologically and for pathogenic activity, e.g., O-inagglutinability, haemolytic activity, necrotic effect etc. However, it should be kept in mind that any specific O-antigens may be detected from those strains isolated from sick animals: O-78 for calf scours, O-138, O-139, O-141 etc. for "oedema disease" of swine. In man, the socalled "enteropathogenic E. coli" have been found, while such a term has not been used so often for any ill conditions due to E. coli infection in animals. On the other hand, piggery has been hitherto raised considerably in recent years. Therefore, various ill conditions appear to increase gradually at piggery stations, involving abortion, growth disorder, infectious diseases etc. One of bacterial infections, i.e. E.coli infection is wellknown as a disease of swine. This infection referred to as "colibacillosis" appears to be usually characterized by acute enteritis, septicemic form, oedema disease etc. The author's attempt was to observe the characters of strains of E. coli isolated from either normal or ill pigs at Kochi city, with special reference to its serotyping and pathogenic mechanism. A fact that any specific types of E. coli of swine origin may cause any specific infection should be confirmed. Such a concept made him found numerous strains of E. coli, which should be classified clearly into valuable biochemical and serological types. That is, the distribution of such specific types of E. coli at any special locations will suggest for the occurrence of E. coli infection in pigs. The results mentioned later may contribute to prophylaxis or control of E. coli infection of pigs to some extent. Escherichia coli is wellknown as a species among the family Enterobacteriaceae, which lives in intestines of healthy animals as a normal microflora. Therefore, a question, whether strains of healthy animals are same as those of any ill individuals or not, will be raised. If any difference could be found between both strains, any particular strains of definite serotypes might be established for causes of ill conditions. Furthermore, chemotherapeutic therapy for bacterial diseases including E. coli infection has been already investigated by many workers. However, most antibiotics have not been necessarily found to show any remarkable therapeutic effect against E. coli infection. A reason for such a fact has been found to be due to the presence of the socalled "drug-resistant factor". The author has not studied such a factor at this time, but his concept was devoted to a possibility of any drug-resistant strains of E. coli for a causal agent of its infection of swine. His observations on outbreaks of E. coli infection in pigs were performed for such symptoms as diarrhoea of piglets of 7 days after birth, and, at the same time, for healthy piglets of the same age. And, E. coli strains isolated from fecal samples of both origin were tested morphologically, biochemically and serologically. Furthermore, antagonism was found between some strains of swine origin and those of human origin. Also, sensitivity test for drugs was carried out on representative strains. The most remarkably important test was found to be on agglutination test. Because the author's attempt was to establish antigenic relations between newly isolated strains of E. coli of swine origin, as untypable strains distinct from KAUFFMANN - WHITE schema should be classified into 4 new specific serotypes named by him. II. The characters of Escherichia coli of different origin. Materials and methods: 1. Isolation of E. coli strains. a) Period of sampling: January to December, 1968; and January to October, 1971. b) Location: 10 piggery farms at Kubokawa-cho, Takaoka-gun, Kochi-ken. c) Animal: 50 piglets suffering from diarrhoea, and those 50 in clinically healthy condition. d) Sample: rectal feces. e) Culture medium: direct cultivation on MacConKey's medium, and thereafter incubation for 24 hours at 37℃. 2. Biochemical identification of isolated E. coli strains. Biochemical characterization of E, coli species was carried out due to socalled "IMviC System" by subcomittee for Enterobacteriaceae in International Association of Microbiology. Therefore, the author attempted to observe biochemical characters of isolated E. coli strains of swine origin, according to BERGEY's Manual of Determinative Bacteriology, 7th Ed. (1957), and the resolution of the 8th meeting of the above association. After all, urease medium, KCN medium, malonate medium, gelatin medium, christensen's medium, etc., were employed to test E. coli strains identified with "IMViC System", and, furthermore, cytochrome test and carbohydrate fermentation test were carried out. 3. Serological observation. Serotyping of isolated E. coli strains was carried out by performing agglutination test with specific anti-O-sera for standard E. coli strains as KAUFFMANN's O-groups. a) Preparation of antigen: a killed saline suspension obtained by heating at 121℃ for 2.5 hours of agar culture, and by washing twice the dead bacterial cells was employed for antigen. b) Polyvalent anti-O-serum, and 36 individual anti-O-sera as follows. O-1, O-2, O-3, O-4, O-5, O-6, O-7, O-8, O-9, O-10, O-11, O-21, O-26, O-27, O-28, O-42, O-44, O-55, O-65, O-78, O-81, O-86, O-111, O-118, O-119, O-124, O-125, O-126, O-127, O-128, O-136, O-138, O-139, O-143, O-144, O-146 respectively. 4. Observation of drug-sensitivity. Sensitibity test against different antibiotics was carried out for 33 strains to be identified by anti-O-sera. Drugs used were 14 antibiotics such as penicillin (P), streptomycin (S), kanamycin (Ka), tetracycline (T), erythromycin (E), leucomycin (L), chloramphenicol (C), oleandomycin (Ol), colistin (K), sulfisoxazole (i), spiramycin (Sp) polymyxin B (Px), nalidixic acid (Nd), lincomycidin (Li), and another drug as furazolidone. Results: 1. Colonial findings of 50 strains isolated from piglets suffering from diarrhoea i.e. "white scours", and 50 strains isolated from those clinically healthy, to be identified with E. coli. Typical pink smooth colonies of E. coli grown on MacConKey's medium were picked up and isolated as pure culture on slant agar medium. These E. coli strains were tested biochemically. As a result, positive indole-reaction, positive MR-reaction, negative VP-reaction, negative Simmons-citrate reaction, growth possibility at 44℃., and negative gelatinase-activity made us classify all the strains into "E. coli I" type, negative indole-reaction into "E. coli II type", and growth inability at 44℃ into "E. coli III" type respectively as follows. (White scours) (Healthy piglets) E. coli I 49 strains 50 strains E. coli II 1 0 E. coli III 0 0 2. Biochemical characters of above-mentioned isolated strains. a) Those of 50 E. coli strains of "white scours" origin. As showin in TABLE I, all strains were Gram-negative, and decomposed glucose rapidly with gas formation, and also lactose, xylose, maltose, and mannitol within 48 hours. Sucrose, salicin, and dulcitol showed variable reactions for fermentation test, but adonitol was decomposed by 3 strains. Christensen's medium showed a negative reaction for 12 strains. Litmus milk was coagulated by 48 strains within 6 days, but only 2 strains were found to be negative even after 14 days. Indole reaction was positive for the majority of strains except only one negative strain. VP-reaction, H_2S formation, IPA, utilization of SIMMONS citrate, malonate, and urease, and gelatinase activity, and growth ability in KCN medium were all negative for all the strains, only one hemolytic strain was found. Motility was positive for 30 strains, but negative for 20 strains. (TABLE 1). b) Those of 50 E. coli strains of healthy swine origin. Fifty strains is isolated from 54 healthy piglets of 7 days after birth were tested for 27 items in the same way as 50 strains of "white scours" origin. All 50 strains were found to ferment glucose rapidly, but 3 strains of them have not shown gas-formation. Lactose was decomposed by the majority of the strains except 4 negative strains. Mannitol was found to be positive within 48 hours for decomposition by all strains, but sucrose was positive for only 24 strains, dulcitol and salicin showed variable reaction for decomposition test, adonitol was positive for decomposition by 5 strains, and inositol was positive by 2 strain only. Maltose was negative by 6 strains, and xylose also negative by only one strain. Litmus milk was coagulated within 6 days by 48 strains except for 2 negative strains until 14 days. Indole reaction was positive for all the strains. VP, H_2S, IPA, SIMMONS citrate, urease, gelatinase activity, malonate utility, and growth ability on KCN medium were all negative for all the strains. Motility was positive for 32 strains, but negative for 18 strains. Hemolytic activity was negative for all the strains. CHRISTENSEN's citrate medium test was positive for all the strains (TABLE 2). 3. Serological behaviours of isolated E. coli strains. Of 55 E. coli strains of "white scours" origin, 16 strains were classified into 80-types containing 7 strains(14.0%) of O-139, 2 strains (4.0%) of O-27, 2 (4.0%) of O-118, and each one (2.0%) of O-2, O-8, O-9, O-124 and O-125 respectively. The other 34 strains (68.0%) were all negative to every anti-O-serum, and therefore quite untypable. At the same time, 50 strains of healthy swine origin were also tested for agglutination. However, only 17 strains (34.0%) were classified into 9 O-types containing 6 strains (12.0%) of O-139, 3 (6.0%) of O-27, each one (2.0%) of O-65, O-124, O-127, O-128, and O-65 respectively. 33 (66.0%) remaining strains were found to be untypable due to be inagglutinable to every anti-O-serum (TABLE 3). As mentioned above, 100 strains in total of both "white scours" and healthy swine origin - were found to be classified into 32% for the former, and 34% for the latter respectively, pointing to 8-9 sero-groups (TABLE 3). It must be remembered that the strains of type O-139 have been hitherto detected often from oedema disease, gastro-enteritis etc. in pigs. The author has also isolated this sero-type from white scours of piglets, and its frequency of occurrence was proven to be significantly different from that of other sero-types (p<5%). 4. Drug-sensitivity of isolated E. coli strains. Sensitivity of 33 strains of swine origin to various drugs was tested as shown in TABLE 4, which had been serologically identified Of these strains, 16 ones of "white scours" origin were detected to be most sensitive to polymyxin B, nalidixic acid, colistin, chloramphnicol, kanamycin, and furatolidine; moderately sensitive to sulfisoxazol and tetracycline; and weakly sensitive or resistant to penicillin, streptomycin, erythromycin, leucomycin, oleandomycin, spiramycin and lincomycidin. On the other hand, 17 strains of healthy swine origin were found to be most sensitive to polymyxin, nalidixic acid, and kanamycin while moderately sensitive to chloramphenicol, colistin and furatolidine, and also almost nonsensitive to penicillin, streptomycin, tetracycline, erythromycin, leucomycin, oleandomycin, sulfisoxazol, spiramycin, and lincomycidin. After all, presence of resistant strains was found against such various antibiotics except for furatolidine and polymyxin, and so it must be noted that such resistant strains exist against antibiotics which are known to be effective for Gram-negative bacteria. That is, of 16 strains of "white scours" origin, 12 were resistant against streptomycin, one against kanamycin, two against tetracycline one against chloramphenicol, and 8 against sulfisoxazol. Also, of 17 strains of healthy swine origin, 14 were resistant against streptomycin, one against kanamycin, one against tetracycline, 7 against chloramphenicol, one against colistin, 13 against sulfisoxazol, and one against nalidixic acid (TABLE 4). In sensitivity test for 15 antibiotics, poly-drug-resistant strains were detected from healthy swine origin as follows. Type O-128 was resistant against 11 drugs, O-146 against 10 drugs, O-27 and O-65 against 8 drugs, 3 strains of O-139, 2 strains of O-27 and one of O-6 against 7 drugs, type O-139 against 6 drugs, O-143, O-127 and O-6 types against 5 drugs, and O-124 against 4 drugs respectively (TABLE 5). On the other hand, among the strains of "white scours" origin, type O-2 was found to be resistant against 9 drugs, O-118, and 2 strains of O-139 against 7 drugs, O-118, O-124, O-9 and 5 strains of O-139 against 6 drugs, O-27 against 5 drugs, O-8, O-125 and O-27 against 4,drugs respectively. III. The characters of Escherichia coli strains of healthy adult swine. Materials and methods: In the previous parts of the article, there have been described various characters of E. coli strains isolated from both healthy and "white scours" piglets. Thus, the occurrence of carriers among piglets has been more or less wellknown for definite serotypes (i.e. O-antigens) of E. coli, and also the definite serotypes have been thought to associate with definite diseases. However, there has been little information for healthy adult carriers of any definite E. coli serotypes. Therefore, the author attempted to observe any relation between any definite serotypes and adult swine. 1. Sampling of materials from pigs. For this purpose, healthy slaughterd pigs were submitted to sample fecal material and some organs. Retal feces was submitted to direct cultivation on MacConKey's medium. The period of sampling was from June to November. Pigs slaughtered were 25 heads at 20℃, 41 at 20˚-25℃., and 84 at 25˚-30℃. respectively. The majority of them were 84 females and 57 castrated males. 53 of them were 7 months, 39 were 6 months, and 30 were 8 months aged. Animals over 10 months after birth were those adults which had already become useless for breeding. All the pigs consisted of 118 Yorkshire, 30 Landrace, and 2 Berkshire. Feeding conditions for these pigs were classified into both special form and common form. The former means feeding with special feed, and the latter that with miscellaneous feed. In slaughter at abattoirs, some pathological lesions such as hemorrhage in instestines, nephritis, pneumonia etc., were detected from 5 pigs. Therefore, sampling was carried out for the lungs, liver, spleen, and small intestine. From pigs other than those, fecal samples from colon alone were submitted to cultivation. 2. Growth of colonies of E. coli from Adult swine. Cultural finding on MacConKey's medium was shown in Fig. 1. 3. Morphology of isolated strains. Morphology of isolated strains was observed by Giemsa's stain of air-dried films from fresh culture incubated for 24 hours at 37℃. The Giemsa's pigment had been diluted in aqua destillata at pH=6.8 before use. 4. Biochemical tests for isolated strains. The method of biochemical identification with E. coli species was same as the case in part II. Besides such a method, the reaction against milk casein was observed for 30 days at room temperature after an incubation for 24 hours at 37℃. Furthermore, changes in coagulated casein was also observed with paper-chromatography. 5. Preparation of anti-O-sera for isolated strains. Many isolated E. coli strains of swine origin were found to be negative against KAUFFMANN's anti-O-sera. Therefore, the author attempted to design an agglutination method by using specially prepared anti-O-sera due to immunization of rabbits with 4 representative strains (i.e. A, B, C, and D types) as follows. anti-A-seruni: ..... immunization with type A-strain (i.e. motility+, sucrose fermentation-). anti-B-serum: ...... immunization with type B-strain (i.e. motility-, sucrose fermentation-). anti-C-serum: ...... immunization with type C-strain (i.e. motility-, sucrose fermentation+). anti-D-serum: ...... immunization with type D-strain (i.e. motility+, sucrose fermentation+). Each immunogen was a suspension of pure culture consisting of smooth form. The end titre of each antiserum was found to be over 1:10.000 against O-antigen of its homologous strain. The antiserum had been kept as a 50% glycerinized solution after inactivation for 30 minutes at 56℃. Antigen: The antigen used for agglutination test with the above mentioned serum was as follows. A suspension heated at 100℃ for one hour of culture of the test strain was prepared. If the suspension was inagglutinable, it was further ther heated at 121℃ for 2 1/2 hours. Incubation of the antigen and the serum mixed in equal volume was carried out for 2 hours at 37℃., and thereafter the mixture was further left overnight to read any reaction. Titres over 1:1000 were judged to be positive or available reaction. 6. Sensitivity test of E. coli strains for antibiotics. E. coli strains of swine origin which were found to be of β-hemolytic type, tolerable to milk culture for one month at room temperature were employed for sensitivity test as a method of disc paper. 7. Test for antagonistic action of E. coli strains of swine origin against those of human origin. The test was carried out also with the paper disc method. Results: A. Colonial forms of isolated strains. As showin in TABLE 7, 11 colonial forms such as A, B, C, D, E, F, G, H, I, K and L in the strains of healthy adult origin were found. Colonies of type A as typically round, pink and smooth forms occupied 21.54% of all colonies, and those of type K as small round forms amounted to 59.29%. Thus, these both types were found to occupy the majority of grown colonies on MacConKey's medium. On the other hand, those of type A were found at the highest percentage in colonies grown from visceral organs of 5 ill adult pigs, while none of type K were found. This fact seems to be considerably significant as compared with the case of the former healthy adult swine origin. B. Morphology . of isolated strains. As a remarkable finding of E. coli strains of adult swine origin was of bipolar staining for Giemsa stain, and such a phenomenon was more clear in old culture. Besides this, there was found a tendency to pleormorphism. C. Biochemical characters of isolated strains. 1. Classification by IMViC system. According to IMViC system, 93(65.4%) of 142 strains of human food-poisoning origin were identified with "E. coli 1". These strains had been isolated just in the chance when adult swine were slaughtered. On the other hand, 370 (86.9%) of 426 strains of healthy adult swine origin and 7 (46.6%) of 15 strains of ill adult swine origin were also identified with "E. coli 1". Therefore, 92.9% strains of adult swine origin were found to be occupied by "E.coli 1" 2. Biochemical characters. 107 of 377 strains identified with "E. coli 1" were submitted to biochemical test, and, as its result, 9 of those 107 strains were found not to belong to E. coli. Therefore, 98 remaining strains showed almost typical characters for E. coli, e.g., 97.9% for lactose, 95.9% for maltose, 98.9% for mannitol, 32.6% for salicin, 64.2% for xylose, 28.5% for sucrose and 5.1% for adonitol. 3. Reaction to protein. Coagulation of milk by 90 E. coli strains of swine origin was shown by the majority of them, e.g., 61.2% in 1-2 days, 8.5% in 3 days, and 26.5% in 14 days, but 8 strains had shown no coagulation. D. Serological characters of isolated strains. 222 strains biochemically identified with E. coli including 98 initially identified ones and 124 later added ones were submitted to agglutination test with antisera for KAUFFMANN's standard E. coli strains (as O-antigens). As a result, there was found a considerably interest tendency that 62 serologically identified strains had shown different agglutinability depending upon room temperature (TABLE 14). That is, there appeared many agglutinable strains at high temperature, while the number of agglutinable strains were decreasing gradually with fall of temperature. The difference of frequency between the number of agglutinating strains at over 20℃. and that at below 20℃. was significant. Furthermore, agglutinating strains against antisera of low figures of O-antigens, e.g., O 1～O 10 etc. tended to be detected at the highest percentage. In short, the agglutinability of E. coli strains of swine origin was found to have a significant correlation (r=-0.46) to both room temperature and figures of O-antigens. Furthermore, strains possessing O-2, O-83 and O-101 antigens respectively of 62 tested strains were found most frequently among 27 O-factors detected positively agglutinable against 134 O-factor sera. Several definite sero-types of Escherichia coli are associated with their infection (i.e. so called "coli-bacillosis")in pigs. In this case, the aspects of the infection are of the main forms such as acute sporadic septicemia, acute gastroenteritis, and the so called "oedema disease". The author have observed typical cases of "white scours" of baby pigs. Vaserinus (1966) has reported on "the factors influencing the rapid multiplication of enteropathogenic porcine Escherichia coli strains". In his studies on this them, he emphacises, in particular, colicinogenicity and fermentative properties of porcine E. coli strains. Besides the article, there have been already numerous researches on E. coli infections of pigs in Japan, too. In the view point of diagnosis of such diseases, in general, bacteriological inspection of faecal samples appears to be most significant. Because definite enteropathogenic E. coli strains will be able to multiply most rapidly and luxuriously in small intestines. In particular, certain serotypes are know to excrete a definite exotoxin in the case of oedema disease of pigs. Above all, baby or young pigs are always most susceptible to infections of E. coli, while adults have already acqired some resistance against the infection. Pathogenic types of E. coli detected by the author have been found to be classified in to 8 serotypes due to 8 different somatic antigens: 16 strains (32.0%) consisting 7 strains (14.0%) of O-139, 2 strains (4.0%) as O-118 and O-27, and each one strain (2.0%) of O-2, O-8, O-124 and O-125 isolated from faecal samples of pigs suffering from "white scours". According to Vaserinus's observation, there is an alternative of E. coli serotyps depending upon different years. As compared with such a conclusion, the observation by the author has been summarized as follows. Difinite serotypes of E. coli will be found always at the definite area of piggeries : That is, the distribution certain pathogenic E. coli serotypes will be recognized to locate permanently at the definite places of piggeries. It will be interested that the same serotypes of E. coli of porcine origin have been isolated both in Europe and our country. Contamination by definite serotypes at piggeries where baby pigs are nursed by their sows must be strictly explored bacteriologically, and healthy individuals should be isolated from unhealthy circumstances. Chemotherapeutic treatment of patient pigs should be rather substituted by other preventive measures from the view point of immunological controls. Because immune adults appear to give passively protective antibody (i.e. immune globulin) to their healthy new born pigs through colostrum, and the serum of immune adults will contain some doses of antibody. On the other hand, carriers of any definite serotypes of E. coli among any pig population should be detected bacteriologically as quickly as possible to be omitted. IV. Newly designed serotyping of Escherichia coli of swine origin by means of antisera prepared for its representative strains of swine origin. The control of E. coli infection of pigs will be attained successfully. From the authors view point, there were found in pigs several inagglutinable strains strains of E. coli against KAUFFMANN's O-factor anti-sera of standard strains of E. coli. Such a new discovery made him to identify or characterize these inagglutinable E. coli strains as follows. Taking the differences of biochemical characters into consideration, 4 strains which had different patterns for motility and saccharose fermentability were selected to submit to preparation of 4 new anti-sera by means of immunization of rabbits. As these 4 representative strains were antigenically different, all the inagglutinable strains could be classified into 5 different serotypes by means of agglutination test with such 4 anti-sera. Conclusion. The following summary was established from the above mentioned observations. That is, the isolated strains of E. coli from pigs can be identified with their origin, and in particular, those from adults indicate significantly the presence of carriers or reservoirs of definite serotypes of E. coli to be pathogenic sources. After all, three conclusions will be metioned as follows. a. Definite serotypes of E. coli can be significantly isolated from pigs being raised at definite areas. b. Poly-resistant strains against antibiotic drugs are found among E. coli strains of swine origin. c. E. coli strains of swine origin proven to be inagglutinable to KAUFFMANN's O-antisera of E. coli can be classified into 5 new serotypes. |
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| 学位名 | ||||||||||
| 学位名 | 獣医学博士 | |||||||||
| 学位授与機関 | ||||||||||
| 学位授与機関名 | 麻布大学 | |||||||||
| 学位授与年月日 | ||||||||||
| 学位授与年月日 | 1973-03-24 | |||||||||
| 学位授与番号 | ||||||||||
| 学位授与番号 | 乙第 57号 | |||||||||
| 著者版フラグ | ||||||||||
| 出版タイプ | AM | |||||||||
| 出版タイプResource | http://purl.org/coar/version/c_ab4af688f83e57aa | |||||||||
