Endoscope disinfection; disruptive behavior in the OR; conjunctival contamination risk; surgical hand rubbing

AORN Journal, Oct, 2006 by George Allen

Flexible endoscopes cannot withstand heat sterilization, so they are decontaminated by cleaning and then disinfected with a sterilant or high-level disinfectant. Standard guidelines for reprocessing endoscopes recommend exposure to 2% glutaraldehyde for 10 to 20 minutes for gastrointestinal (GI) endoscopes. Although glutaraldehyde is effective against most viruses, fungi, and vegetative bacteria, it requires longer contact time to kill atypical mycobacteria and Bacillus species. Additionally, glutaraldehyde is associated with health problems such as dermatitis, conjunctivitis, and asthma among endoscopy personnel.

Alternatives to glutaraldehyde include peracetic acid, super oxidized water, orthophthaldehyde, and chlorine dioxide. Chlorine dioxide is a powerful oxidizing agent that has been used for slime control and treatment of drinking water. Preparations of chlorine dioxide in high concentrations of 700 parts per million (ppm) to 1,100 ppm are known be effective against most bacteria, fungi, viruses, resistant atypical mycobacteria, and spore-forming bacteria. Fumes given off during use, however, may cause irritation. It is believed that reprocessing endoscopes using lower concentrations of chlorine dioxide in an automated endoscope washer-disinfector can be an effective means for reprocessing GI endoscopes, and the lower concentrations of chlorine dioxide can reduce staff member contact, thus providing a safer working environment. The purpose of this study was to evaluate the microbicidal properties of low-level chlorine dioxide solution and the effectiveness of an automated washer-disinfector for reprocessing GI endoscopes using chlorine dioxide after upper GI examinations. (1)

As an initial step, the researchers at a university hospital in Japan assessed the in vitro microbicidal activity of diluted (ie, 30 ppm) and undiluted (ie, 600 ppm) chlorine dioxide against

* methicillin-resistant Staphylococcus aureus (MRSA),

* methicillin-resistant Staphylococcus epidermidis (MRSE),

* alpha-hemolytic Streptococcus,

* Enterococcus faecalis (E faecalis),

* Klebsiella pneumoniae (K pneumoniae),

* Enterobacter cloacae (E cloacae),

* Mycobacterium avium-intracellulare (M avium-intracellulare) complex, and

* Candida albicans (C albicans) that were obtained from clinical specimens from the hospital. Commercially available

* Escherichia coli (E coli) American Type Culture Collection (ATCC) 25922,

* Pseudomonas aeruginosa (P aeruginosa) ATCC 27853,

* Bacillus subtilis (B subtilis) ATCC 6633,

* Serratia marcescens (S marcescens) ATCC 8100, and

* Helicobacter pylori (H pylori) ATCC 49503

were used as controls.

Next, a video endoscope was used for upper GI screening of 60 patients who underwent the first procedures on each day endoscopic procedures were performed at the facility. Twenty-four of the patients were diagnosed as having H pylori infection, and six patients were diagnosed as having hepatitis C virus (HCV). After an endoscopic procedure, the endoscope was wiped with sterile gauze, forceps and aspiration channels were rinsed with 20 mL of saline, and the resulting gauze and saline samples were cultured. Manual cleaning, which consisted of washing the instrument surface and accessible channels with an enzymatic detergent, was performed according to established guidelines. The endoscope then was soaked randomly in either 2% glutaraldehyde for 10 minutes or a 30-ppm chlorine dioxide solution for five minutes, and subsequently was cultured.

The researchers then evaluated the antimicrobial effects of the automated washer-disinfector specially fitted for chlorine dioxide. The concentration of and exposure time to chlorine dioxide were set at 30 ppm for five minutes. The endoscope was used for upper GI examinations on 30 patients, of whom 12 were known to be infected with H pylori and five were known to be infected with HCV. The endoscope was cultured before and after cleaning and disinfection using the automated endoscope washer-disinfector. The concentration of chlorine dioxide was monitored daily before use, and the solution was discarded after each procedure.

Findings. Both 30-ppm and 600-ppm chlorine dioxide solutions as well as 2% glutaraldehyde killed MRSA, MRSE, alpha-hemolytic Streptococcus, E coli, E faecalis, K pneumoniae, E cloacae, P aeruginosa, S marcescens, H pylori, and C albicans within 10 seconds of contact time. Chlorine dioxide at both concentrations killed M avium-intracellulare complex within 60 seconds, whereas 2% glutaraldehyde showed bactericidal effects only after 300 seconds of contact time.

Eleven bacterial species and C albicans were recovered just after the procedure from the endoscopes used on 42 of the 60 patients (70%). Although seven microbial species grew from endoscopes immediately after

endoscopic examination in 19 of 30 patients (63%) whose endoscopes were cleaned with 30-ppm chlorine dioxide, no microbial species were recovered from the endoscope after reprocessing in the automated endoscopic processor using 30-ppm chlorine dioxide. No functional or cosmetic damage was noted in the instruments or accessories during repeated applications of chlorine dioxide or 2% glutaraldehyde.