Stanford E. Sumida

Mycobacteria and glutaraldehyde: is high-level disinfection of endoscopes possible?

BACKGROUND High-level disinfection of endoscopes has traditionally been undertaken by manual or automatic scope cleaning plus a 10 to 20 minute soak in 2% alkaline glutaraldehyde. Mycobacteria species are less sensitive to glutaraldehyde, and a 45-minute instrument soak has recently been recommended by the manufacturer. Because of concerns over endoscope damage, need for more endoscopes, and perception that the current cleaning method is adequate, we prospectively studied mycobacteria-contaminated endoscopes at various stages of the cleaning process. METHODS All work was done under a laminar flow hood in a microbiology laboratory. Five gastrointestinal scopes were contaminated with 10(8) colony forming units per milliliter (CFU/mL) of Mycobacterium chelonei, an atypical mycobacterium similar in chemical resistance to Mycobacterium tuberculosis but with less infectious potential. Cultures of the sheath, biopsy channel, and elevator channel were taken at baseline, after manual cleaning, and after 10, 20, and 45 minutes to glutaraldehyde soak both before and after alcohol rinse. RESULTS Manual cleaning resulted in a mean of 4.7 log10 reduction in viable mycobacterial colonies. Qualitative studies of the external endoscope surface as well as the air-water valve showed no detectable organisms after a 10-minute exposure to alkaline glutaraldehyde. Conventional quantitative culture techniques of the channels demonstrated one endoscope out of five with consistent growth after a 10-minute exposure to glutaraldehyde. Following alcohol treatment, there was no significant colony growth. In contrast, a quantitative membrane filter system showed the presence of at least one mycobacterial colony in four out of five scopes after a 45-minute glutaraldehyde exposure. CONCLUSIONS Additional studies utilizing a standardized mycobacterial species, inoculum size, and suspension characteristics are recommended to delineate adequate duration of disinfectant exposure time.

Disposable versus reusable biopsy forceps: a prospective evaluation of costs ☆ ☆☆ ★ ★★ ♢

BACKGROUND Disposable biopsy forceps have been heavily marketed as cost-effective, convenient, and safer to use than conventional forceps. METHODS In an attempt to define whether disposable or reusable biopsy forceps were cheaper to use, we prospectively evaluated the purchase price, number of uses, repair record, and cleaning costs of all reusable biopsy forceps used in the outpatient endoscopy unit of a large multispecialty clinic. RESULTS Over a 12-month period, 1581 biopsy sessions were undertaken. Seventeen of 119 forceps required

Risk of contamination of sterile biopsy forceps in disinfected endoscopes

1890 in repairs over the study period (an average of

In vitro and in vivo evaluation of a reusable double-channel sphincterotome

1.20 per biopsy session). Cleaning costs, including technician processing and steam autoclave, approximated

In vitro evaluation of integrity and sterilization of single-use argon beam plasma coagulation probes

3.46 per use, increasing to

⁎3415 In-vivo evaluation of reusable biopsy forceps: chapter 2.

5.61 per use if glutaraldehyde soak was substituted for steam autoclave. CONCLUSIONS Assuming a sixfold difference in purchase price between reusable and disposable forceps, and a per-use repair and cleaning cost of

⁎3341 Single-use biopsy forceps: does sterility upon insertion prevent contamination at time of biopsy?

1.20 and

3416 Photodynamic therapy probes: can they be reused?

3.46, respectively, reusable biopsy forceps became cost-effective after seven uses in our institution.

Reusable biopsy forceps: a prospective evaluation of cleaning, function, adequacy of tissue specimen, and durability.

BACKGROUND Previous studies have shown that pathogens may persist within bacterial biofilms in endoscope accessory channels despite high-level disinfection. Breaching the gastrointestinal mucosa with biopsy forceps contaminated at time of passage has the potential to cause cross-infection between patients. METHODS We studied contamination risk of sterilized biopsy forceps passed through endoscopes after high-level disinfection. For each trial, five video colonoscopes, duodenoscopes, and gastroscopes were used. All endoscopes had been previously processed and stored for 10 or more hours. Sterile biopsy forceps were inserted and retrieved followed by vortexing the tips in 15 mL of soy broth. Under a laminar flow hood, the broth was filtered through a 0.2 microm millipore membrane and plated. Because of minimal bacterial growth resulting from the above, soy broth (> 20 mL) was flushed through two video colonoscopes, duodenoscopes, and gastroscopes on two occasions and collected. The effluent was plated using a sample of 0.1 mL dilution. The remaining suspension was passed through a millipore filter, and the filter was cultured. All cultures were incubated more than 48 hours. RESULTS Biopsy forceps underwent a total of 24 anaerobic and 75 aerobic cultures. Microbacterial growth occurred on 17 plates: 7 from gastroscopes, 5 from colonoscopes, and 5 from duodenoscopes. Fifteen plates grew staphylococcus for a total of 21 colonies, 1 plate grew 1 colony of propionibacter, 2 plates grew diphtheroids for a total of 4 colonies, and 1 plate grew a single colony of lactobacillus. Cultures from soy broth flushed through the various endoscopes grew on 5 plates: 3 from gastroscopes and 2 from duodenoscopes grew a total of 8 colonies of staphylococcus. CONCLUSIONS With proper cleaning technique, a 20-minute soak in 2% glutaraldehyde is effective in disinfecting endoscopes. Although current procedures for endoscope disinfection remain imperfect, we found that in this clinical setting, infection of pathogenic gastrointestinal flora is unlikely when using sterile biopsy forceps.

In vitro evaluation of wire integrity and manuual processing of single-use spincterotomes

BACKGROUND To date, one reusable, double-channel sphincterotome has been approved by the Food and Drug Administration in the United States. Whether this device can be reprocessed easily and whether it is more durable than currently manufactured disposable sphincterotomes are uncertain. METHODS Thirty double-channel, 20 mm, braided-wire sphincterotomes approved for multiple uses were studied in vitro/in vivo with regard to durability and sterilization. A cost analysis of reusable, disposable, and reprocessed disposable sphincterotomes was also carried out. RESULTS Three of 10 sphincterotomes evaluated in vitro broke after 3, 4, and 8 uses. Electrical integrity was preserved after 10 uses in the remaining sphincterotomes. Nine sphincterotomes remained functional for at least 3 uses, five for 6 uses, and one for 10 uses. Culture results after inoculation demonstrated contamination with surviving organisms after manual cleaning and no growth after ethylene oxide sterilization. Sixty-one procedures were performed in vivo using 20 sphincterotomes (mean number of uses 3.1). No evidence of procedurally related infection occurred with reuse. Cost per use of this reusable sphincterotome was calculated to be