JP2969133B2 - Eradication method of Legionella bacteria in water system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sterilizes bacteria in a cold / hot water system or a heat storage water system, such as circulating cooling water for a refrigeration system and circulating hot water for a 24-hour bath, in particular, bacteria of the genus Legionella and prevents their proliferation. About the method.

[0002]

2. Description of the Related Art In refrigeration systems used for air conditioning equipment, refrigeration or freezers, circulating water cooled using an open cooling tower or the like is often used in order to efficiently exchange heat. Microorganisms and the like easily enter the circulating water and proliferate, causing heat exchange efficiency of the heat exchanger to be reduced due to slime, causing obstacles such as filter clogging, and pathogenic bacteria, particularly Legionella bacteria. Proliferation and dispersal cause specific pneumonia, such as Legionnaires' disease and Pontiac fever.

[0003] As a countermeasure against such problems caused by microorganisms, a method of injecting an antibacterial agent into the circulating water system to suppress the growth of bacteria, a method of physically cleaning and cleaning the inside of the apparatus, or a method of chemically using a cleaning agent are used. Cleaning methods and the like have been used.
Various compounds have been conventionally proposed as fungicides for controlling Legionella spp., But even if they show a bactericidal effect in a laboratory, they are not always sufficient when they are used in an actually operating water system. In many cases, the effect was not obtained.

[0004] In addition, it is known that Legionella bacteria in the natural world, even when ingested by bacterial predatory protozoa such as amoeba, proliferate and parasitize as parasites.
However, it was not clear how such a symbiotic relationship between Amoeba and the like and Legionella bacteria affects the fungicide resistance of Legionella bacteria.

[0005] On the other hand, it is known that pyridinium salt compounds have antibacterial activity, and have conventionally been used for various applications as disinfectants and bactericides. However, it was not considered to be particularly effective for removing bacteria of the genus Legionella by adding it to cooling water or the like.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the fact that there has been no effective means for preventing the growth of Legionella bacteria in an aqueous system, in particular, Legionella bacteria in a state coexisting with amoeba or the like. It is an object of the present invention to provide a method for effectively eliminating bacteria of the genus Legionella in an aqueous system, particularly an amoeba coexisting water system.

[0007]

SUMMARY OF THE INVENTION An object of the present invention as described above is to provide the following chemical formula A, chemical formula B, chemical formula C for an aqueous system in which amoeba and Legionella bacteria coexist .
Formula D, Formula E, or Formula F
Of the Legionella bacterium in an aqueous system to which a pyridinium salt compound selected from the compounds to be added is added.

[0008]

Embedded image In the formula, R is an alkyl group , X is any of Cl, Br, and I, and Y and Z are each —H, —COO.
H, -NH2.

Embedded image In the formula, R ₁ is an alkyl group , R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is any of Cl, Br, and I.

Embedded image In the formula, R ₁ is an alkyl group , R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is any of Cl, Br, and I.

Embedded image In the formula, R ₁ is an alkyl group , R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is any of Cl, Br, and I.

Embedded image In the formula, R ₁ is an alkyl group , R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is any of Cl, Br, and I.

Embedded image In the formula, R ₁ is an alkyl group , R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is any of Cl, Br, and I. The above chemical formulas
In the above, R and R ₁ are an alkyl group having 6 to 16 carbon atoms.
And R ₂ is a polymethylene group.
In some cases, it may be a polymethylene group having 2 to 8 carbon atoms.
preferable.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The method for removing Legionella bacteria in an aqueous system according to the present invention is not limited to the case where Legionella bacteria alone is present in an aqueous system, and particularly, amoebae and Legionella bacteria coexist. By adding a pyridinium salt compound to an existing water system, both bacteria and protozoa can be controlled, and Legionella bacteria can be very effectively eliminated.

In the method of the present invention, the amount of the pyridinium salt compound added to the aqueous system may be in the range of 1 to 1000 mg / L, but from the viewpoint of economy and the like, it is 1 to 500 mg / L.
It is preferable to add it so that it is in the range of mg / L. Also,
There is no particular limitation on the method of adding the pyridinium salt compound to the water system, but the method of intermittent addition to the target water system at intervals of several days to one month, or the method in which the concentration of the drug in the water system is constant A method of continuously adding the water to make-up water or the like can be used so as to maintain the value at or above the value, and a sufficient sterilization effect can be obtained by these methods.

The pyridinium salt compound used for the eradication of bacteria belonging to the genus Legionella includes, for example, dodecylpyridinium-iodide of the formula A
Compound, for example, 4,4 '-(hexamethylenedithio)
Compounds of formula B shown in the above formula such as bis (1-octylpyridinium-bromide), for example, 4,4′-
Compounds of the formula C shown in the above formula such as (hexamethylenedioxydicarbonyl) bis (1-octylpyridinium-iodide), for example, N, N'-hexamethylene-bis (1-decyl-4-carbamoylpyridinium- Bromide), N, N'-hexamethylene-bis (1
-Dodecyl-4-carbamoylpyridinium-bromide) such as 4,4 '-(tetramethylenedicarbonyldiamino) bis (1-decylpyridinium-bromide), 4,4'
-A compound of formula E as shown in formula 11 such as-(p-phthalamido) bis (1-octylpyridinium-bromide), for example N, N'-hexamethylene-bis (1-dodecyl-4-carbamoylpyridinium-bromide)
And the like.

In using the pyridinium salt compound according to the method of the present invention, agents such as a corrosion inhibitor, a scale inhibitor, and a dispersant, which are blended in a general water treatment agent, can be used in combination. Examples of such concomitant drugs include 1-hydroxyethylidene-1,1-diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, polymaleic acid, polyacrylic acid, phosphinic acid or a salt thereof, orthophosphoric acid or a phosphoric acid thereof Salts, polymeric phosphates, molybdates, nitrites, silicates, water-soluble zinc compounds and the like can be mentioned.

[0013]

EXAMPLES (First Example) Legionella (Legionella pn) was plated on a BCYEα plate medium having the composition shown in Table 1.
eumophila) and cultured at 36 ° C. for 2 days.

[0014]

[Table 1] BCYEα plate medium pure water 1000 mL yeast extract 10.0 g ACES buffer 10.0 g L-cysteine monohydrochloride 0.4 g soluble iron pyrophosphate 0.25 g α-ketoglutaric acid 1.0 g activated carbon powder 1 0.5 g agar 15 g pH 6.9

Next, a pyridinium salt compound represented by the formula A
Dodecylpyridinium-iodide (abbreviated as P-12); 4,4 '-(hexamethylenedithio) bis (1-octylpyridinium-
Bromide) (abbreviated as S-6,8), 4,4 '-(hexamethylenedioxydicarbonyl) bis (1-octylpyridinium-iodide) (4DOC
BP-6,8), N, N'-hexamethylene-bis (1-decyl-4-carbamoylpyridinium-bromide), a compound of formula D (abbreviated as 4BP-6,10) and N, N '
Hexamethylene-bis (1-dodecyl-4-carbamoylpyridinium-bromide) (abbreviated as 4BP-6,12),
4,4 '-(tetramethylenedicarbonyldiamino) bis (1-decylpyridinium-bromide) (abbreviated as 4RBP-4,10) and 4,4'-(p-phthalamido) bis (1 -Octylpyridinium-bromide) (abbreviated as 4DCABP-P, 8), a compound of formula F N,
N'-hexamethylene-bis (1-dodecyl-4-carbamoylpyridinium-bromide) (abbreviated as 3BP-6,12) was prepared and, for comparison, is a known fungicide instead of a pyridinium salt compound. A drug containing 10.1% of 5-chloro-2-methyl-4-isothiazolin-3-one and 3.8% of 2-methyl-4-isothiazolin-3-one (a product of Rohm and Haas Company) , KATHON
WT) and 2-bromo-2-nitropropane-
1,3-diol (generic name: bronopol, abbreviated as BRNPOL) was prepared.

Then, after inoculating the above cultured Legionella in a phosphate buffer of pH 7 so as to have an order of 10 ⁴ cells / mL, a part of the solution is applied to a BCYEα plate medium,
By counting the number of colonies after 5 days of culture at 36 ° C., it was measured viable cell count, 3.3 × 10 ⁴ cells /
mL. Next, this solution was dividedly put into each culture flask, and a fungicide-free one and a fungicide to which the above-mentioned fungicides were added at concentrations of 1, 5, 10 and 50 mg / L, respectively, were prepared. After culturing with shaking at 37 ° C. for 24 hours, the viable cell count (cells / mL) was measured in the same manner as described above. Table 2 shows the values of the viable cell count after cultivation thus obtained.

[0017]

[Table 2]

From the results shown in Table 2, it can be seen that the pyridinium salt compound has substantially the same bactericidal activity against Legionella as compared with conventionally known bactericides.

(Second Example) A culture flask containing a PYGC medium having the composition shown in Table 3 was inoculated with Acanthamoeba, cultured at 30 ° C. for 4 days, the old medium was discarded and new PYGC was removed. Add the medium and add the first
In the same manner as in the example, Legionella cultured on a BCYEα plate medium for 2 days was inoculated, and cultured at 30 ° C. for 4 days so that amoeba and Legionella coexisted.

When the medium in the culture flask was stirred to remove the amoeba from the wall surface, a part of the culture solution was dropped on a hemocytometer and the amoeba number was measured under a microscope. It was 10 ⁶ cells / mL. Further, another part of the culture solution was taken out, centrifuged at 10,000 rpm for 20 minutes to destroy the amoeba, applied to a BCYEα plate medium, and counted for the number of colonies after culturing at 36 ° C. for 5 days. , Legionella was measured to be 8.9 × 10 ⁵ cells / mL.

[0021]

[Table 3] PYGC medium pure water 950 mL Protease peptone 10.0 g Yeast extract 10.0 g 50% dextrose aqueous solution 20 mL L-cysteine monohydrochloride 0.95 g Sodium chloride 5.0 g 0.5 M hydrogen phosphate 2 Sodium aqueous solution 20 mL 0.5 M potassium dihydrogen phosphate aqueous solution 10 mL 0.4 M magnesium chloride aqueous solution 5 mL 0.4 M calcium chloride aqueous solution 1 mL pH 6.5

The same fungicides used in the first embodiment were added to a culture flask containing a culture medium in which the amoeba and Legionella coexisted at 10, 30, and 100 mg / L, respectively.
, And those without a bactericide were prepared and cultured at 30 ° C. for 7 days. Then, after examining the form of the amoeba by microscopic observation, the culture solution is stirred to disperse the amoeba and Legionella evenly, and a part of the culture solution is taken out at 10,000 rpm for 2 hours.
After centrifugation for 0 minutes to destroy the amoeba, B
The number of viable Legionella cells (cells / mL) was measured by counting the number of colonies after plating on a CYEα plate medium and culturing at 36 ° C. for 5 days, and the results are shown in Table 4.

On the other hand, another part of the above-mentioned uniformly mixed and dispersed culture solution was directly inoculated into a new PYGC medium, and cultured at 30 ° C. for 7 days, to examine the viability of the amoeba. In addition to the results of the above microscopic observation, Table 4 also shows the state of living as a vegetative body as +, the state of living as a cyst as ±, and the state of dying as −.

[0024]

[Table 4]

From the results shown in Table 4, it can be seen that a conventionally known bactericide exhibiting excellent bactericidal activity against Legionella cannot effectively eliminate Legionella in the presence of amoeba, whereas the pyridinium salt compound does not effectively dissolve Legionella. It also shows that it has a biocidal power and can effectively remove Legionella coexisting with amoeba.

[0026]

According to the present invention, the addition of a pyridinium salt compound to an aqueous system eliminates Legionella bacteria in the aqueous system, which seems to have been impossible with conventional fungicides for Legionella bacteria. Has the effect of effectively eliminating Legionella bacteria in an aqueous system in the presence of amoeba, and even when used as a highly concentrated aqueous solution, foams like a general quaternary ammonium salt. Is not so significant that there is an advantage that handling is easy.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 1/50 532 C02F 1/50 532D 532H 540 540B A01N 43/40 101 A01N 43/40 101K C12N 1/20 C12N 1/20 Z (72) Inventor Akihiro Shirai 50-11 Suginamidai, Yuki-cho, Saiki-gun, Hiroshima Prefecture (56) References JP-A-2-43989 (JP, A) JP-A-52-102425 (JP, A) JP-A-8- 253402 (JP, A) JP-A-5-194113 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C02F 1/50 A01N 43/40 101

Claims (2)

(57) [Claims] 1. An aqueous system in which amoeba and a bacterium belonging to the genus Legionella coexist with the following chemical formulas A, B and
Any of Formula C, Formula D, Formula E and Formula F
A method for removing bacteria belonging to the genus Legionella in an aqueous system, comprising adding a pyridinium salt compound selected from the compounds represented by the formula: Embedded image In the formula, R is an alkyl group, X is any of Cl, Br, and I, and Y and Z are each -H, -COOH, -N
H2. Embedded image In the formula, R ₁ is an alkyl group, R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is Cl,
Br or I. Embedded image In the formula, R ₁ is an alkyl group, R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is Cl,
Br or I. Embedded image In the formula, R ₁ is an alkyl group, R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is Cl,
Br or I. Embedded image In the formula, R ₁ is an alkyl group, R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is Cl,
Br or I. Embedded image In the formula, R ₁ is an alkyl group, R ₂ is a polymethylene group having 2 or more carbon atoms or a p-phenylene group, and X is Cl,
Br or I. Wherein amount of the pyridinium salt compound 1
The method for removing bacteria of the genus Legionella in an aqueous system according to claim 1 , wherein the amount is in the range of -1000 mg / L.