Reprocessing in digestive endoscopy units in Lombardy: results of a regional survey

'Secondary biofilms' could cause failure of peracetic acid high-level disinfection of endoscopes

INTRODUCTION

The reduced susceptibility of biofilms to disinfectants presents a challenge to the successful reprocessing of medical equipment. This study examined the effect of residual biomass remaining after previous disinfection with peracetic acid (PAA) on the tolerance of subsequent mature Pseudomonas aeruginosa biofilms to PAA. The effect of enzymatic degradation of specific components of the extracellular polymeric substance (EPS) of P. aeruginosa biofilm on the effectiveness of PAA disinfection was also evaluated.

METHODS

The susceptibility of biofilm grown on the biomass of PAA-killed biofilm to PAA was compared with the PAA susceptibility of biofilm grown in wells of a 24-well plate by evaluating their viability using the plate count assay. The effect of PAA on biofilm biomass was measured using crystal violet quantification of total biofilm biomass, while its effect on the polysaccharide and protein components of biofilm EPS was quantified using the phenol-sulphuric acid assay or Bradford assay, respectively. A confocal microscope was used to visualize the distribution of living and dead cells in biofilms grown on residual biofilm biomass.

FINDINGS

The presence of residual biomass from previously disinfected biofilms significantly enhanced the tolerance of subsequent biofilms. A 96-h-old 'secondary biofilm' formed on disinfected biomass survived PAA concentrations of 4000 ppm, which exceeds the concentrations used in practice for high-level disinfection.

CONCLUSION

These observations indicate that, under certain circumstances, recolonization of residual EPS can cause failure of disinfection of medical equipment such as endoscopes, and emphasizes the importance of cleaning endoscopes prior to disinfection.

Survey of endoscope reprocessing in Korea

Background/Aims

There is a growing emphasis on quality management in endoscope reprocessing. Previous surveys conducted in 2002 and 2004 were not practitioner-oriented. Therefore, this survey is significant for being the first to target actual participants in endoscope reprocessing in Korea.

Methods

This survey comprised 33 self-filled questions, and was personally delivered to nurses and nursing auxiliaries in the endoscopy departments of eight hospitals belonging to the society. The anonymous responses were collected after 1 week either by post or in person by committee members.

Results

The survey included 100 participants. In the questionnaire addressing compliance rates with the reprocessing guideline, the majority (98.9%) had a high compliance rate compared to 27% of respondents in 2002 and 50% in 2004. The lowest rate of compliance with a reprocessing procedure was reported for transporting the contaminated endoscope in a sealed container. Automated endoscope reprocessors were available in all hospitals. Regarding reprocessing time, more than half of the subjects replied that reprocessing took more than 15 minutes (63.2%).

Conclusions

The quality management of endoscope reprocessing has improved as since the previous survey. A national survey expanded to include primary clinics is required to determine the true current status of endoscope reprocessing.

Is peracetic acid suitable for the cleaning step of reprocessing flexible endoscopes?

The bioburden (blood, protein, pathogens and biofilm) on flexible endoscopes after use is often high and its removal is essential to allow effective disinfection, especially in the case of peracetic acid-based disinfectants, which are easily inactivated by organic material. Cleaning processes using conventional cleaners remove a variable but often sufficient amount of the bioburden. Some formulations based on peracetic acid are recommended by manufacturers for the cleaning step. We performed a systematic literature search and reviewed the available evidence to clarify the suitability of peracetic acid-based formulations for cleaning flexible endoscopes. A total of 243 studies were evaluated. No studies have yet demonstrated that peracetic acid-based cleaners are as effective as conventional cleaners. Some peracetic acid-based formulations have demonstrated some biofilm-cleaning effects and no biofilm-fixation potential, while others have a limited cleaning effect and a clear biofilm-fixation potential. All published data demonstrated a limited blood cleaning effect and a substantial blood and nerve tissue fixation potential of peracetic acid. No evidence-based guidelines on reprocessing flexible endoscopes currently recommend using cleaners containing peracetic acid, but some guidelines clearly recommend not using them because of their fixation potential. Evidence from some outbreaks, especially those involving highly multidrug-resistant gram-negative pathogens, indicated that disinfection using peracetic acid may be insufficient if the preceding cleaning step is not performed adequately. Based on this review we conclude that peracetic acid-based formulations should not be used for cleaning flexible endoscopes.

Current status of cleaning and disinfection for gastrointestinal endoscopy in China: a survey of 122 endoscopy units

BACKGROUND

Adequate compliance with the existing guidelines for cleaning and disinfection of gastrointestinal endoscopes and accessories is necessary to obtain high-level disinfection and prevent pathogen transmission.

AIM

To investigate cleaning and disinfection practice in China.

METHODS

A questionnaire with 21 questions concerning gastrointestinal endoscopy reprocessing was sent by e-mail to 189 endoscopy units in China.

RESULTS

One hundred and twenty-two (80.39%) of the 189 units responded. Compared with the low-workload units (<5000 procedures/year), the high-workload units (≥5000 procedures/year) had a significantly higher number of gastrointestinal endoscopes (25.8 ± 3.6 vs. 4.7 ± 1.8, p < 0.01) and the higher possessing rate of automated endoscope reprocessors (43.9% vs. 3.1%, p<0.01). Glutaraldehyde was the most commonly employed disinfectant (88.5%) in all the units. In 23/122 (18.8%) units, the exposure time to glutaraldehyde was <45 min in the case of infectious disease patients. Eighty-six of 122 (70.5%) units reused disposable materials, of which 21/86 (24.4%) reused disposable forceps and disposable polypectomy hooks, and 2/86 (1.6%) reused disposable injection needles intermittently.

CONCLUSION

Although gastrointestinal endoscopy has developed rapidly in China in the past decade, there is still room for improvement in the practice of endoscopy reprocessing, especially in middle-sized and small cities.