著者

越智 勇一 勝部 泰次

出版者

社団法人日本獣医学会

雑誌

日本獸醫學雜誌 (ISSN:00215295)

巻号頁・発行日

vol.20, no.4, pp.171-177, 1958-08-30

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The authors previously rerorted on the bacterial flora of the udders ofhealthy" and mastitis cows," as well as on the bacteriological classification of theisolated organisms."I. Comparison of the bacterial flora of the udders of healthy and mastitis cows.As for the normal flora of the udders, (3 herds, 53 cows, 201 quarters)Staphylococcus was the most predominant and Bacillus, Corynebacterium, Stre-ptococcus, Gafkya, Sarcina, Gram-negative bacilli and Fungi were usolated witha lessening frequency in the order listed. Staphylococcus, Streptococcus, Bacillus,Gafkya, Corynebacterium and Gram-negative bacilli were isolated in the stateof either pure culture or predominant to the other organisms at the rate of 42,9, 6, 5, 4 and 1%, respectively. Two or more kinds of organisms were isolatedin an almost equal quantity in 29% and no viable organisms were isolated in2,96.As for the bacterial flora of mastitis cows, (100) Streptococcus was isolatedmost frequently and Bacillus, Gram-negative bacilli, Staphylococcus, (:oryne-bacterium, Sarcina, and Gafkya were isolated less frequently in the order listed.Streptococcus, Corynebacterium, Staphylococcus, and Gram-negative bacilli wereisolated in the state of either pure culture or predominant to the other organismsin 51, 11, 9 and 9%, respectively. Two or more kinds of organisms weremsolated in an almost equal amount in I7g and bacterial isolation was negativein 3%.IT. Relation between our classification of the organisms isolated frorn norrnaludders and bovine mastitis.I) StreptococcusLactococcus group was predominant in both the healthy or the diseasedudders next in frequency was Enterococcus group and the least frequent wasSlre ptococcus group.2) StaphylococcusAs for the normal flora of udders, Staphylococcus type II was observedrnost frequently (89%), Staphylococcus type I came next (9,961), Staphylococcustype III was least in frequency (1%).In the case of rrnastitis, Staphylococcus type I comprised 40% of the organisnxsisolated and Staphylcccccus type II, 60%. Out ofwas Staphylococcus type II and this moreover, was isolated with a considerableamount of Escherichiae.3 ) CorynebacteriumAll the organisms isolated from normal udders were Corynebacteriumpseudodiphthericum, while the organisms isolated from cases of of mastitis, 70%were identified as Corxnebacterium pxoxenes and 30% as Corxnebacterium pseudo-diphthericuwt.In the case of mastitis out of the 11 cases from which ()orynebaeterittmwas isolated in the state of either pure culture or predominant to otherorzanisms, 9 cases were Corxnebacterium pxozenes and 2 cases were Cortne-bacterium pseudodiphthericum, one being mixed with Streptococcus and the otherwith Escherichiae and Streptococcus.4) Gram-negative bacilliA few strains isolated from normal udders were identified as Enterobacter-iaceae, while many strains isolated from the cases of mastitis were identified asEschet"ichiae.In the case of mastitis, out of the 9 cases from which Gram-negative bacilliwere isolated in the state of either pure culture or predominant to the otherorganisms, 8 cases were Escherichiae and 1 case was Protetts, mixed withStreptococcus.Isolation of Gafkya and Sarcina was low in frequency and Bacillus wasrather high from both normal and mastitis udders. In the case of mastitis,however, these organisms were not isolated in the predominant state.On the basis of the above mentioned results, Streptococcns, especiallyLactococcus nrouv, StaPh;lococcus tvr>e I, Corxnebacterittm P?ozenes and Escheri-chiae are regarded as the most important causative agents of bovine mastitis.Since all the causative agents of bovine mastitis are the organisms found111 the normal flora, the authors consider that bovine mastitis is a disease causednot merely by the organisms themselves but requires some predisposing factorsplaced on the udders which allow active multiplication of these organisms andsuggest that it is a poly-bacterial non-specific disease which can be included inthe 0CHIS theory of autogenous infectious diseases. The authors have already reported a survey on the incidence of Iarval lung-flukes,Paragonimus ohirai, in Sesarma dehaani collected from the Xlaruyama River, in HyogoPrefecture.In the present study, immature P. ohirai obtained from the abdominal cavity ofwhite rats 15 to 24 days after their infection by metacercariae, were transplanted intothe peritoneal cavity of uninfected rats. It was the purpose of this work to producerats harboring a known number of these lung-flukes, as well as to gain a better under-standing of the biological natures of these implanted flukes and the course of the infec-tion in the experimental hosts.The experiment was made on a total of 15 adult white rats exposed, individually,to from l to 4 young adult worms : of these, five received 1 worm each, five received 2worms each, three received 3 worms each and two received 4 worms each. These ani-mats were killed between the 21st and 97th days after the infection, and the distributionof the adult worms and worm cysts in the host was examined macroscopically andmicroscopically.The results obtained are as follows(l) The number of young adult worms recovered from the lungs and pleural cavityof the hosts as adult worms, namely, the rate of infection by these implanted flukes,was 100% with the exception of rat 14 as shown in Table I.(2) In the rats individually exposed to only one young adult worm, all of theimplanted flukes remained free in the pleural cavity of the host without invading intothe lung tissue, throughout the entire period of the investigation. Therefore, in theseaninnals no clear evidence of elimination of the eggs in the feces, or their entry intothe cavity formation in the lungs, were observed. On the other hand, in the rats indi-vidually exposed to from 2 to 4 young adult worms, all of the implanted flukes enteredinto the lung tissue of the host, where they formed the typical worm cysts. These ratsalso began to pass the eggs in their feces between the 18th and 37th days after the in-fection by immature P. ohirai.(3) The implant once or twice, the peak egg count throuughout the entire period of the investigation, asshown in Fig. 2 to 4. The first peak egg count (2,850 to II,250EPG) occurred betweenthe 4th and 16th days, and the second one (3,816 to TO,TOO F,PG) between the 19th and31st days after the beginning of patency. As soon as the fecal egg production reacheda peak, it rapidly fell to a low level of between O and 183 eggs per gram of feces.(5) It is suggested, therefore, that the transitory decrease in the egg count to nega-tive or near negative may be connected with a removal of the dwelling place of theimplanted flukes in the lungs of their hosts.EXPLANATION or PLATESPlate I1=3. Showing the morphology of the young adult worms of P. ohirai used in the experiment.1. Young adtnlt worm from the alcdominal cavity of a rat 15 days after infection by meta-cercariae, mounted specimen. 0.225 by 0.118 rum.2. Young adult worm from the abdominal cavity of a rat 20 days after infection by meta-cercariae, mounted specimen. 0.338 by 0.170mm.3. Young adult worm from the abdominal cavity of a rat 24 days after infection by meta-cercariae, mounted specimen. 0.388 by 0.195 mm.4?13. Showing the distribution of the worm cysts in the lungs of rats which had received a youngadult worm of P. ohirai, respectixxely. (No cavity formation was observed in the lungs of any ofthese rats as shown in the photographs.)4. Cross section of the left lung of rat 1.5. Cross section of the right lung of rat 1.6. Cross section of the left lung of rat 3.7. Cross section of the right lung of rat 3.8. Cross section of the left lung of rat 6.9. Cross section of the right lung of rat 6.10. Cross section of the left lung of rat 7.11. Longitudinal section of the right lung of rat 7.12. Cross section of the left lung of rat 8.13. Cross section of the right lung of rat 8.14?23. Showing the distribution of the worm cysts in the lungs of rats which had received twoadult worms of P. ohirai, respectively.14. Cross section of the left lung of rat 5.15. Cross section of the right lun cyst, containing no worm. It forms a cavity due to softening the lung tissue.23. Cross section of the left and right lungs of rat 19. In the right lung a cut surface of ayounger worm cyst which contains two adult worms is seen. It forms a cavity due tosoftening of the lung tissue.Plate II24?31. Showing the distribution of the worm cysts in the lungs of rats which had received threeyoung adult worms of P. ohirai, respectively.24. Cross section of the left lung of rat 10. There are seen the cut surfaces of a younger wormcyst (A) from which a living adult worm (B) had been recovered, and an older one (C). Theformer forms a cavity due to softening of the lung tissue, while the latter, a cavity due to thedilation of the bronchtus.25. Another cross section of the left lung of rat 10. There are seen the cut surfaces of a youngerworm cyst (A) which contains two adult worms, and two older ones (B, C). The oneforms a cavity due to softening of the lung tissue, while the others, the cavities due to thedilations of the bronchi.26. Cross section of the right lung of rat 10. There are seen the two older worm cysts (A, B).Each of them forms a cavity due to the dilation of the bronchus.27. Cross sections of the left lung and the intermediate Robe of the right lttng of rat 15.28. Cross section of the right lung of rat 15. There are seen the cut surfaces of a younger wormcyst (A) which contains two adult worms, and an older one (B) which contains a deadadult worm. Each of them forms a cavity due to the dilation of the bronchus.29. Cross sections of the left lung and the intermediate Robe of the right lung of rat 18.30. Cross section of the right lung of rat 18. There is seen a cut surface of a younger wormcyst (A) from which two living adult worms (B) had been recovered. It forrms a cavitydue to softening the lung tissue.31.