Bioburden and transmission of pathogenic bacteria through elevator channel during endoscopic retrograde cholangiopancreatography: application of multiple-locus variable-number tandem-repeat analysis for characterization of clonal strains

ABSTRACT

Objectives: Endogenous and exogenous infection of the biliary tract could occur during endoscopic retrograde cholangiopancreatography.

Methods: Bile samples of patients with hepatobiliary diseases, and swab samples of elevator channel samples of duodenoscope and washing instruments were prepared simultaneously and cultured aerobically and anaerobically. Antimicrobial susceptibility of the most common characterized bacterial species was tested, and their genetic relatedness was analyzed by multiple locus variable number of tandem repeats method.

Results: Contamination with Pseudomonas aeruginosa was detected in 38.2% of the elevator channels’ and 26.6% of the bile samples. Staphylococcus aureus, Enterococcus spp., Staphylococcus epidermidis, Escherichia coli, Enterobacter spp., and Clostridium perfringenes were among other bacterial isolates in the elevator channel swab samples. Highest antimicrobial resistance rate among P. aeruginosa isolates from the bile and swab samples were detected against gentamicin (100% and 73%, respectively), while the lowest one was measured to piperacillin-tazobactam (25% and 0%, respectively). Out of the 27 distinct MLVA profiles, relatedness of P. aeruginosa strains in the bile samples compared with those from the elevators was shown in three series of the samples.

Conclusion: Identity of P. aeruginosa strains among the bile and elevator channel samples showed possibility of cross-contamination among patients even at distinct time intervals.

Expert opinion: Bacterial infection is considered as main complications of ERCP. Entry of bacteria into the biliary tract via contaminated device and its related instruments and their proliferation in this tissue could cause serious infections. To prevent this side effect, reprocessing of medical equipment via standard cleaning and disinfection procedures are needed. Our results showed incompliance of methods used for endoscope cleaning and disinfection procedure. Although host risk factors, such as sphincterotomy, could increase rate of infection with different types of bacteria, their ability for formation of biofilm and spore, which could help them to resist disinfectants and washing procedures seems to be main cause of persistent colonization and transmission among different patients. New standards for disinfection compared with currently used methods and use of materials to eliminate formation of bacterial microcolonies seem to be necessary to prevent cross-contamination.

KEYWORDS:

• Pseudomonas aeruginosa
• endoscopic retrograde cholangiopancreatography
• bioburden
• cross-contamination
• MLVA typing

Article highlights

• Both aerobic (e.g. P. aeruginosa), anaerobic (e.g. C. perfringenes), and members of the enteric bacteria were shown as main cause of bactobilia.

• Patients with underlying diseases, such as sphincterotomy, are more likely to experience mixed type infection of the biliary tract.

• Although prophylactic therapy is advised in patients with underlying diseases, change in therapeutic regimen based on the bile culture results could control severe and fatal complications of post-ERCP infections.

• Standard disinfection procedure can reduce colonization rates of biofilm forming bacteria in the elevator channel of endoscopes.

This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Authors contributions

M Alebouyeh, A Houshang M Alizadeh, and A Sadeghi: Conception and design of the study; M Azimirad, Laboratory experiments and analysis, Paper Drafting; M Alebouyeh, Critical revising; Final approval of the last version; E Khodamoradi, sampling and initial screening of the samples; A Sadeghi, M Reza Zali, and H Asadzadeh aghdaei: Medical examination and endoscopic procedure. All authors agree to be accountable for all aspects of the work.

Additional information

Funding

This study was financially supported by Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Behehsti University of Medical Sciences, Tehran, Iran.