Increasing Disinfection Efficacy of Glutaraldehyde via Chemical and

Chapter 17

Increasing Disinfection Efficacy of Glutaraldehyde via Chemical and Physical Enhancement

Downloaded by PENNSYLVANIA STATE UNIV on August 6, 2012 | http://pubs.acs.org Publication Date: September 7, 2007 | doi: 10.1021/bk-2007-0967.ch017

Wei Shen, Yilin Ge, and Yi Su Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, People's Republic of China

As a biocide, glutaraldehyde (GA) acts via a complex crosslinking mechanism and the 2%GA solution is one of the most popular high-level disinfectant solutions for medical instrument processing. However, it takes 4 hours to produce complete killing of 10 Bacillus subtilis var. niger spores. In this study, chemical and physical synergisms with 2%GA are evaluated for their enhancement of sporicidal efficacy, reduction of GA concentration and shortening of the use time. 6

348

© 2007 American Chemical Society

In New Biocides Development; Zhu, P.; ACS Symposium Series; American Chemical Society: Washington, DC, 2007.

349 Findings based on the research performed in our labouratory: (1) Complete killing of 10 Bacillus subtilis var. niger spores was achieved in 2 hours when 2%GA was used in combination with either a cationic surfactant (two examples). (2) The complete destruction of HBsAg (Hepatitis B Surface Antigen) was demonstrated when 2%GA was used in combination with a cationic surfactant within 5 minutes (vs. 30 minutes without a surfactant). (3) Complete killing of 10 Bacillus subtilis var. niger spores was achieved in 4 hours when 1%GA only was used in combination with a catatonic surfactant. The reduced GA concentration benefits health care workers for the reduced tendency of causing allergic dermatitis and eye, respiratory irritation. (4) The combined synergisms from both chemical and physical means were investigated. Thus, the 2%GA in combination with a cationic surfactant, at 40°C with ultra sonication led to the complete killing of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Mycobacterium chelonae subsp.abscessus (all in 10 concentration); complete inactivation of Poliovirus-I [TCID (Tissue Culture Infective Dose) x 10 ] and HBsAg within 5 min; killing of Bacillus subtilis var. niger spores in less than 10 minutes (10 concentration) or less than 30 minutes (10 concentration). (5) The above synergisms can be applied to endoscopes processing in shorter time. 6


6

6

6

50

3

6

Background Glutaraldehyde (1,5-pentanedial) is

a saturated dialdehyde whose

molecular structure is OHC—CH —CH -CH —CHO. 2

2

2

The 2% glutaraldehyde (GA) is one of the most popular high-level disinfectants and chemical sterilants for medical instrument processing. Advantages of GA include the following: excellent biocide properties; activity in the presence of organic matter; non-corrosive action on endoscopic equipment, thermometers, and metal, rubber or plastic equipment; and noncoagulation of proteinaceous material. 1


350 6

However, it has to take 4 hours for GA to effect complete killing of 10 Bacillus subtilis var. niger spores; it has caused procititis because of GA exposure from residual endoscope's solution; keratopathy was reported to be caused by ophthalmic instruments that were inadequately rinsed after soaking in 2%GA; it is irritating to the eyes, throat, and nose of health care workers with expose of more than 0.2 ppm GA vapor; epistaxis, allergic contact dermatitis, asthma, and rhinitis have also been reported in health care workers exposed to GA. Objectives of this study are: enhancing sporicidal efficacy via chemical and physical synergisms; shortening the use time of disinfection and sterilization to satisfy clinical requirements; reducing the use concentration of GA to decrease exposure to GA.


M

Materials and Methods Test microorganisms 1. 2. 3. 4.

Vegetative forms of bacteria: Escherichia coli (8099), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 15442). Bacterium spore: Bacillus subtilis var.niger spore (ATCC 9372). Mycobacterium: Mycobacterium chelonae subsp. abscessus (A TCC 93326). Viruses: HBsAg, Poliovirus-1

Synergisms of glutaraldehyde 1. Nonionic surfactants A (fatty alcohol polyoxyethylene ether): R-0-(CH CH20)nH R represents a mixture of alkyl whose number of carbon is 12-15. 2

B (propylene glycol polyoxyethylene polyoxypropylene ether):

CH -(C H 0) (C H 0) 2

3

6

a 1

2

4

32

b 1

CH CH OH 2

2

b2

CHO-(C H 0) (C H 0) CH CH OH 3

CH

6

2

4

2

2

3


351 2. Cationic surfactants


C (alkyl dimethyl benzyl ammonium bromide):

R represents a mixture of alkyls whose number of carbon is 8-12. D (alkyl dimethyl benzyl ammonium chloride):

CH

3

R represents a mixture of alkyls whose number of carbon is 8-12.

3. Anionic surfactants E (sodium dialkyl ester sulfosuccinat):

ROOC — C H I ROOC—CHS0 Na 2

3

R represents a group of alkyls whose number of carbon is 8. F (sodium dodecyl sulfate):

C H 50S0 Na 12

2

3


352 4. Amphoteric surfactants G (alkyl dimethyl betaine):

+

R-N (CH ) CH COO " 3

2

2

R represents a mixture of alkyls whose number of carbon is 12-14. +

H (sodium dodecyl sulfate + MgCl ): C H OS0. Na MgCI


2

12

25

3

2

Test method Quantitative suspension bactericidal, virucidal and mycobactericidal tests.

Results 1. Screening synergisms of GA Two of nonionic surfactants (A, B), two of cationic surfactants (C, D), two2 of anionic surfactants (E, F) and two amphoteric surfactants (G, H) were tested. 6

1.1 Complete killing of 10 Bacillus subtilis var. niger spores was achieved in 2 hours when 2%GA was used in combination with either a cationic surfactant (two examples). (Table 1) 1.2 The complete destruction of HBsAg was demonstrated when 2%GA was used in combination with a cationic surfactant (two examples) within 5 minutes (vs. 30 minutes without a surfactant). (Table 2)

2. Probing disinfection Efficacy of less than 2% GA with synergism The reduced GA concentration benefits health care workers for the reduced tendency of causing allergic dermatitis, eye and respiratory irritation. 6

2.1 Complete killing of 10 Bacillus subtilis var. niger spores was achieved in 4 hours when 1% GA was used in combination with a catatonic surfactant (Table 3, Figure 1).


353


Table 1. Efficacy of 2%GA in killing B. subtilis var.niger spores with synergism of different means. Disinfectants (pH=6.8-7.2)

Spore count (cfu/ml) after exposure Compared with 2% GA JUI

UIJJK

UJ

0.5

I IMG

J

2

1

X

P

2

2% G A

244000

2 % G A + A

466000

19300

133

0.31

2% G A + B

279000

54000

320

0

2 % G A + C

94900

1540

0

7.69

Increasing Disinfection Efficacy of Glutaraldehyde via Chemical and

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