海水のサルモネラ汚染ならびに汚染指標菌に関する研究 : I. 海水中のサルモネラと汚染指標菌の分布

瀬戸内海の環境汚染調査の一環として1972年6月から1974年3月にわたり,福山市沿岸海水を対象にサルモネラと汚染指標菌の動態について調査した。その結果,以下のような成績が得られた。
1. 8地点(A～H)から採取した海水のサルモネラ陽性率は,平均12.1%(28/232)であった。
2. サルモネラ陽性率は地点および季節によって異なり,A地点23.9%(11/46),B地点21.7%(10/46)およびE地点25%(3/12)と陽性率が高く,また季節別では5～10月に高かった。
3. サルモネラ陽性率は港内から港外および沖合部に行くに従って低下した。
4. 分離された42株のサルモネラの菌型またはO群は,S.typhimurium, S.thompson, S.anatum, S.infantis, S.give, S.schleissheim, S.schwarzengrund, S.derby, S,montevideo, S.meleagridis, S,binza, S.senftenbergおよび型別不能のO群B,C1,D,E1であった。
5. これらの菌型・群は,以前に著者らが当地方の飼料工場や河川から分離した菌型と大多数は同じであったことから,陸上環境を汚染しているサルモネラが最終的には海水まで汚染していることが明らかとなった。
6. 従って海水のサルモネラ汚染は水産物のサルモネラ汚染にも影響を及ぼしている。
7. 汚染指標菌は大腸菌群,大腸菌および腸球菌の順で菌数ならびに検出率が高く,大腸菌群はほとんどが陽性であったが,他の2者では陰性例も多かった。
8. これら汚染指標菌の菌数が多い海水ほど,サルモネラ検出率が高い傾向にあった。
9. サルモネラならびに汚染指標菌の検出状況と海水温との関係を検討した結果,サルモネラは汚染指標菌の菌数が多く,しかも,水温が19℃以上の海水から検出される傾向があった。

As a part of the survey on environmental pollution of the Seto Inland Sea, Japan, a survey on the ecology of Salmonella and fecal indicator organisms in the sea water samples collected at eight stations (A to H) located on the coast of Fukuyama, was conducted in June 1972 through March 1974.

The results obtained were as follows:
1. The positive rate for occurrence of Salmonella in the samples collected at the eight stations was 12.1% (28/232) in average.
2. It was observed that the frequency of occurrence of Salmonella in the samples varied depending on the sampling stations and on the seasons. Positive rates in Salmonella detection as high as 23.9% (11/46) at St. A, 21.7% (10/46) at St. B, and 25.0 % (3/ 12) at St. E were observed. In the seasonal observations, a higher positive rate of occurrence of Salmonella was observed in the samples collected during May through October.
3. The frequency of incidence of Salmonella in the samples lowered as the sampling station went from the inner part of Fukuyama Port to the outer part of the Port and the offshore area.
4. Some of the forty-two strains of Salmonella isolated were serotyped to S. typhimurium, S. thompson, S. anatum, S. infantis, S. give, S. schleissheim, S. schwarzengrund, S. derby, S. montevideo, S. meleagridis, S. binza and S. senftenberg, and the O-groups B, C1 , D and E 1.
5. Most of the serotypes isolated in the present study were similar to those isolated previously from the river waters and feed-stuffs in this district by the authors. According to the results, it was proved that those serotypes of Salmonella contaminating the terrestrial environment have also contaminated the coastal marine environment as a terminal stage in the pollutive circulation.
6. The marine contamination with Salmonella may result into the contamination of marine products.
7. The higher values of the MPN and frequency of occurrence of the fecal indicator organisms were observed according to the order to coliforms, E. coli and enterococci. The incidence of coliforms was positive in most of samples examined, but those of the others were negative in some cases.
8. A high tendency of Salmonella recovery was observed in cases that represented high values in the MPN of fecal indicator organisms.
9. As a results of consideration on the relationship between the sea water temperature and the frequency of occurrence of Salmonella and of fecal indicator organisms, it was recognized that there is a high tendency of Salmonella recovery in the sea water samples that showed a high MPN value of fecal indicator organisms and were on a temperature higher than 19° C.