Table 1. Characteristics of included studies.
| First author, year | Study design | Country | Hospital | Endoscopes type(s) | Sampled channels/areas | Positive cultures, n | Sample size, N | Type of microorganism | Reprocessing method | CFU threshold |
| Saliou, 2016 32 | Descriptive study | France | Brest Teaching Hospital | Gastroscopes, colonoscopes, duodenoscopes, echoendoscopes, transnasal gastroscopes, enteroscopes, choledoscope | Working channel, air/water channel, elevator-guidewire channel, waterjet channel | 264 | 762 | Coagulase-negative staphylococci, Bacillus spp., Micrococcus spp., Corynebacterium spp., Enterococcus spp., Actinomyces spp., Brevibacterium spp., Staphylococcus aureus , Streptococcus spp., Streptomyces spp, Pseudomonas spp., Pseudomonas aeruginosa , Stenotrophomonas spp., Klebsiella spp., Rhizobium radiobacter , Acinetobacter spp., Enterobacter spp., Sphingomonas spp., Escherichia coli , Methylobacterium spp., Brevundimonas spp., Citrobacter spp., Moraxella spp., Morganella morganii , Candida spp., Rhodotorula spp., Cladosporium spp., other fungi and yeasts | HLD | > 25 CFU |
| Snyder, 2017 33 | Parallel group randomized study | United States | Beth Israel Deaconess Medical Center | Duodenoscopes | Working channel | 9 | 516 | N/A | HLD, dHLD, HLD/EtO | > 0 CFU |
| Rauwers, 2018 34 | Prospective nationwide cross-sectional study | Netherlands | 67 Dutch ERCP centers | Duodenoscopes | Biopsy channel, suction channel | 9 | 283 | Yeasts, Moraxella spp., Klebsiella pneumoniae, Streptococcus salivarius, Enterobacter cloacae, Moraxella osloensis, Escherichia coli, Streptococcus mitis, Klebsiella oxytoca, Neisseria flavescens, Enterococcus faecium, Rothia spp., Enterococcus faecalis, Streptococcus mutans, Pseudomonas aeruginosa, Streptococcus oralis, Staphylococcus aureus, Streptococcus spp. Bacillus spp., Stenotrophomonas maltophilia, Micrococcus luteus, Acinetobacter spp., Staphylococcus epidermidis, Agrobacterium radiobacter, Kocuria spp., Paracoccus yeeii, Staphylococcus hominis, Achromobacter xylosoxidans, Staphylococcus warneri, Alternaria spp., Kocuria rhizophila, Pseudomonas monteilii, Micrococcus spp., Pseudomonas putida, Staphylococcus auricularis, Sphingomonas paucimobilis, Staphylococcus spp. (CNS), Rhizobium spp. Or Sphingobium spp. | HLD | ≥ 20 CFU |
| Olafsdottir, 2017 9 | Parallel group randomized study | United States | Beth Israel Deaconess Medical Center | Duodenoscopes | Working channel | 52 | 390 | N/A | HLD | > 0 CFU |
| Paula, 2015 35 | Descriptive study | Austria | Vienna University Hospital | Duodenoscopes | Air, water, suction, and biopsy channel | 47 | 412 | Unspecified skin bacteria and aerobe spore-forming bacilli | HLD | > 100 CFU |
| Mark, 2020 13 | Descriptive study | United States | Children’s Hospital Colorado | Duodenoscopes | Working channel | 6 | 117 | Pseudomonas aeruginosa , fungal organisms, Staphylococcus aureus , Coagulase-negative staphylococcus, Streptococcus viridans | HLD | > 10 CFU |
| Alfa, 2012 36 | Descriptive study | Canada | St Boniface General Hospital | Colonoscopes, gastroscopes, duodenoscopes | All channels | 21 | 141 | gram-positive Bacilli, gram-positive Cocci | HLD | N/A |
| Cristina, 2020 15 | Descriptive study | Italy | N/A | Duodenoscopes | Distal end, instrument channel | 35 | 62 | Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, Klebsiella oxytoca, Stenotrophomonas maltophilia, Escherichia coli, Citrobacter freundii, Enterobacter spp | HLD | > 10 CFU |
| Ji, 2018 37 | Descriptive study | China | Unspecified, all endoscopy units in Tianjin, China | Colonoscopes, gastroscopes | Biopsy channel | 104 | 184 | Pseudomonas aeruginosa, Escherichia coli, Acinetobacter lwoffii, Stenotrophomonas maltophilia , Malodorous mononeurosis, Enterococcus faecalis, Testicular pseudomonas, Burkholderia cepacia | HLD | > 20 CFU |
| Chang, 2019 38 | Descriptive study | Taiwan | Unspecified, 14 major tertiary care teaching hospitals | Duodenoscopes | Distal end outer surface, distal attachment cap, elevator wire channel, suction biopsy channel | 43 | 135 | N/A | HLD, dHLD, EtO | N/A |
| Chapman, 2016 39 | Descriptive study | United States | N/A | Echoendoscopes | Suction channel | 22 | 521 | Klebsiella pneumoniae, Citrobacter freundii, Escherichia coli, Pseudomonas aeruginosa, Klebsiella oxytoca, Sphingomonas paucimobilis, Acinetobacter baumanii, Hafnia alvei, Enterobacter cloacae, Pseudomonas putida, Stenotrophomonas maltophilia | HLD | N/A |
| Chiu, 2012 40 | Prospective surveillance study | Taiwan | Chang Gung Memorial Hospital, Kaohsiung Medical Center | Colonoscopes, gastroscopes | Biopsy channel | 57 | 420 | GNGN bacteria, Klebsiella pneumoniae, Acinetobacter baumanni, Enterococcus spp., Comamonas testosterone, Chryseobacterium indologenes, Sphingomonas paucimobilis, Pseudomonas putida, Viridans Streptococcus, Stomatococcus spp., Prevotella bivia, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecium, Bacteroides fragilis, Bacteroides vulgatus, Bacteroides distasonis, Clostridium perfringens, Proteus mirabilis, Moraxella osloensis, Candida glabrata | HLD | 10 3 CFU/mL |
| Valeriani, 2018 41 | Descriptive study | Italy | Unspecified, 10 Italian hospitals | Colonoscopes | Unspecified, inner channels | 5 | 52 | B. vulgatus 16S amplicon, B. vulgatus OmpA, Enterococcus faecalis, Escherichia coli, B. fragilis, S. aureus | HLD | N/A |
| Becq, 2019 31 | Prospective single-center study | United States | N/A | Echoendoscopes | Working channel | 5 | 110 | N/A | HLD | > 0 CFU |
| Duodenoscopes | 14 | 174 | ||||||||
| Chiu, 2012 42 | Descriptive study | Taiwan | N/A | Enteroscopes (DBE) | Suction channel | 9 | 57 | Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, E. aerogenes, A. baumannii, Enterococcus sp., Gm ( + ) bacilli glucose-nonfermenting gp., Proteus vulgaris, Staphylococcus epidermidis, Bacteroides caccae, Prevotella melaninogenica | HLD | N/A |
| Decristoforo, 2018 43 | Descriptive study | Austria | Unspecified, 29 endoscopy centers | Colonoscopes, gastroscopes, duodenoscopes | Biopsy/suction channel | 10 | 218 | Sphingomonas parasanguinis, Streptococcus viridans, Moraxella osloensis, Pseudomonas pseudoalcaligenes, Pseudomonas oleovorans, Pseudomonas luteola, Streptococcus mitis, Moraxella osloensis, Staphylococcus aureus | HLD | ≤ 10 CFU |
| Ribeiro, 2012 44 | Descriptive study | Brazil | Unspecified, gastrointestinal endoscopy units in Belo Horizonte | Colonoscopes, gastroscopes | Air/water channel | 70 | 99 | Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae | HLD | N/A |
| Rauwers, 2020 45 | Prospective nationwide cross-sectional study | Netherlands | 61 Dutch ERCP centers | Duodenoscopes, echoendoscopes 1 | Balloon channel, biopsy channel, suction channel | 13 | 133 | N/A | HLD | ≥ 20 CFU |
| Ji, 2020 46 | Descriptive study | China | Unspecified, 59 Endoscopy units in Tianjin | Colonoscopes, gastroscopes | Biopsy channel | 180 | 280 | N/A | HLD | > 20 CFU |
| Bartles, 2018 47 | Controlled randomized study | United States | Unspecified, four facilities with endoscopy labs | Echoendoscopes and duodenoscopes | Suction and working channel | 84 | 2,925 | Enterococcus spp, Enterobacter cloacae , Aeromonas spp, E. coli (ESBL + ), E. coli (ESBL-), Enterococcus faecium 2 | dHLD, HLD | N/A |
The study was conducted in the main hospitals of different Italian regions (Campania, Emilia Romagna, Lazio, Liguria, Marche, Molise, Tuscany, Veneto, Sardinia, and Sicily) involving ten endoscopy units that reprocess approximately 50–100 endoscopes per business day.
1
Samples from the original biopsy channels for both duodenoscopes and echoendoscopes.
2
Only high-concern pathogens were specified in study.