1234 infection control & hospital epidemiology october 2015, vol. 36, no. 10
table 2. Microbiologic Results of Duodenoscope Surveillance Samples Taken Between 2004 and 2015 Endoscope sampling site
No. (%) of samples taken over the study period (n=412)
Albarran lever Air/water channel
Biopsy/suction channel Endoscope surface
88 (21.4%) 108 (26.2%) 108 (26.2%) 108 (26.2%)
No. of samples with no growth/no. of samples (%)
88/88 (100%) 95/108 (88.0%) 98/108 (90.7%) 84/108 (77.8%)
aThe affected duodenoscope was reprocessed and yielded no growth on resampling. b50 colony-forming units (CFU) aerobe spore-forming bacilli per mL. c>100 CFU aerobe spore-forming bacilli per 10 cm2.
incubated aerobically at 37°C and examined after 24 and 48 h. All possibly significant isolates were identified to species level
using standard microbiologic methods for culture and identi- fication. Colony-forming units were counted and results expressed per 10 cm2 for contact cultures of endoscope surfaces and per mL otherwise. Antimicrobial resistance testing according to current European Committee on Antimicrobial Susceptibility Testing recommendations (
www.eucast.org) was performed. A bacillus subtilis control plate was inoculated to detect residues of disinfectant. Microbiologically sampled endoscope models are listed
in Table 1. Records of microbiologic testing were reviewed retro-
spectively for all endoscopes harboring an Albarran lever from November 2004 through March 2015.
results
There are 8 duodenoscopes in rotational use at the Division of Gastroenterology and Hepatology. Overall there were 4 sites that were evaluated per duodenoscope (inclusive of the Albarran lever). This evaluation yielded a total of 412 micro- biologic monitoring samples during the study period, including 88 samples of the Albarran lever. Results are shown in Table 2. None of the samples taken from the Albarran lever testing site yielded any growth of microorganisms. Contamination with skin bacteria was found in 45 (11%) of the 412 samples. One endoscope tested positive for aerobe spore-forming bacilli. This endoscope was reprocessed and yielded no growth on resampling.
discussion
The difficulties with duodenoscope reprocessing and the associated potential for bacterial transmission have been well documented.2,3 Duodenoscopes are equipped with a mechanical lever called an Albarran lever, whose intricate design requires special attention during reprocessing. For this reason, only sampling data from endoscopes with an Albarran lever were included in our evaluation. In our study none of the samples taken from the Albarran lever testing site showed growth of microorganisms during the
study period. One duodenoscope tested positive for aerobe spore-forming bacilli. Follow-up by the infection control team revealed that the affected endoscope was part of the standby equipment and had not been in use for a prolonged period. Storage conditions of this endoscope were found to be inade- quate. According to written reprocessing standard operating procedures this standby equipment should be reprocessed once a month if not used frequently. Even though performed by highly trained infection control
nurses, collection of the microbiologic samples, which requires sterile techniques, can be difficult with endoscopes being very long and flexible. This, rather than problems in repro- cessing, might explain contamination with skin bacteria found. We attribute the very low overall rate of microorganism
growth in our samples to a multidimensional approach of infection control and quality control measures. Over the past 10 years, the personnel working at the reprocessing department were required to complete training at regular intervals. The arrival of new equipment is paired with reprocessing training. Written reprocessing guidelines are available to all employees and are in conjunction with strict adherence to the manufacturer’s recommendations. Moreover, the personnel turnover at the reprocessing department is low. Equipment upgrade is performed when a device is irreparably damaged but at least after 6 to 7 years. Additionally, the Department of Infection Control conducts periodic microbiologic sample collection of all endoscopic devices each year. The collections are performed by qualified infection control nurses. Surveillance records are archived for 10 years. In Austria, an increase in clinically relevant MDR Enter-
obacteriaceae has been seen during recent years.9 Given the increasing numbers of nosocomial infections due to MDR microorganisms shed with the stool, infection control teams should keep inmind that considerable transmission could occur when MDR bacteriameet insufficient processing of endoscopes. Our findings underline the significance of a standardized and reliable cleaning process of endoscopes before exposure to sub- sequent validated automated cleaning and high-level disinfection in an AEWD. We also strongly support the well-substantiated recommendation by Alfa et al10 for ongoing monitoring of cleaning efficacy of washers used in healthcare facilities. Limitations of our study comprise all the drawbacks of a retrospective study.
No. of positive results other than skin contaminants
0 0
1a,b 1a,c
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