A major challenge in guiding antimicrobial prescriptions for otologic procedures is the lack of widely accepted contamination classification schemes [5, 12, 13]. Even when using the Centre for Disease Control and Prevention’s classification of clean, clean-contaminated, contaminated, and dirty-infected, consensus of where otologic procedures fit is lacking. This challenge exists within other surgical domains evidenced by low inter-rate reliability [14].

Meta-analyzed data in the 2009 Cochrane update grouped tympanoplasty, stapes surgery, and mastoidectomy as clean otologic procedures in the absence of purulent ear discharge [6]. Routine antibiotics would not be indicated except one pre-incisional dose for CI surgery [5, 7]. An argument exists, however, that considers most otologic surgery as clean-contaminated since the middle ear is contiguous with the pharynx via the Eustachian tube and is covered by respiratory epithelium [12]. For clean-contaminated surgery, only a single course of induction antibiotics would be warranted [5]. This discrepancy would explain the lack of consensus within both countries otologists for the use of induction antibiotics in stapes surgery, tympanoplasty, and tympanoplasty with ossiculoplasty. While most Austrian surgeons prescribed induction antibiotics for these procedures (70.6%, 55.6%, 61.1%), most Canadian surgeons either did not prescribe induction antibiotics or remained evenly divided for these procedures (37.5%, 50.0%, 50.0%). Despite the lack of indications for post-operative antibiotics for both clean or clean-contaminated classification, a minority of respondents utilized post-operative antibiotics [5, 7].

Cholesteatoma surgery may be differentiated by the presence of infection, which would change its clean-contaminated status to dirty-infected [5, 6]. A contrasting categorization considers all cholesteatoma surgery as dirty-infected [13]. Some consensus exists between both countries as the majority of surgeons considered infected cholesteatoma as dirty-infected procedures requiring induction and post-operative antibiotics. Dry cholesteatoma lacking purulent debris, however, was a source of differentiation. Irrespective of the contamination classification, induction antibiotics are suggested since dry cholesteatoma surgery is considered at least clean-contaminated. In cases considered contaminated or dirty-infected, a pre-operative dose of antibiotics is linked with a lower post-operative surgical site infection rate [13]. Post-operatively, Canadians were more likely to see dry cholesteatoma surgery as dirty-infected (77.8%) versus Austrians (33.3%) given the use of post-operative antibiotics (Fig. 1). The confusion with classification may be a source of discrepancy in prescribing behaviours of surgeons.

Despite notable differences in prescribing habits between Austrian and Canadian otologists, statistically significant differences were lacking. Only one other published investigation of otologic antibiotic prescribing habits was identified, which evaluated 81 Australian and New Zealand surgeons [15]. Notably, respondents were less likely to use pre-operative antibiotics for CI surgery (62.1%) in comparison to our investigational data. Use of pre- and postoperative antibiotics for stapes surgery was 41.0% and 43.0%, respectively. Comparable prescribing rates for pre- and post-procedural antibiotics were seen for tympanoplasty and ossiculoplasty at 47.2% and 31.0%, respectively. Although the infection status of cholesteatoma surgery was not specified, the Australian/New Zealand surgeons tended to use less induction antibiotics (44.4%) the Austrian and Canadian surgeons in our investigation.

Judicious use of antibiotics is a key pillar in mitigating the health burden antimicrobial resistance (AMR) [16]. Viewed as one of the greatest global health threats to humanity, AMR is challenged by the lack of novel antimicrobials to address pathogens such as carbapenem-resistant gram negatives or third generation cephalosporin-resistant K. pneumoniae [16]. Based on the Organisation for Economic Co-operation and Development’s projections of 52 countries, nearly one quarter of all infections will be resistant to antimicrobial treatment for eight antibiotic-bacterium combinations (Fig. 2) [16]. Even in high-income countries with lower AMR prevalence such as Australia, Austria, and Canada, increased morbidity and mortality are projected unless effective policies are in place to stem the tide [16]. Namely, effectiveness of antibiotic prophylaxis for common procedures while making post-operative infections more difficult to treat [16].

Projected antimicrobial resistance prevalence rates from 2005 to 2030 as per the Organization for Economic Co-operation and Development (OECD)

Given the AMR’s extrinsic threat to global health, surgeons’ assistance in antimicrobial stewardship is imperative. From running well-controlled trials that strengthen antibiotic prophylaxis clinical guidelines to participating in hospital and community infection control programs, numerous opportunities exist for surgeons. Moreover, initiatives such as the “Choosing Wisely,” campaign helps champion antibiotic stewardship by producing informed, evidence-based guidelines to align prescribing patterns while improving patient literacy with antimicrobials.

To support antimicrobial stewardship efforts, the authors believe clearly defining the otologic procedural contamination classification is imperative in combating AMR. Clean surgeries encompass middle ear and canal-wall up mastoid procedures such as tympanoplasty, ossiculoplasty, stapedotomy, and cochlear implantation unless surgical site sterilization cannot be performed. Perioperative antibiotics are not warranted for clean surgeries except for one prophylactic dose for CI surgery [5]. Dry cholesteatoma surgery may be considered contaminated, warranting intraoperative antibiotics followed by a short course of postoperative antibiotics [5, 13]. Procedures involving culture proven infection or the presence of purulence would warrant a dirty classification, which would involve both pre- and post-operative antibiotics.

Several limitations of this investigation exist. Despite the lack of interviewer bias, web-based surveys are subject to a non-response bias. In this investigation, nearly 44.6% of eligible surgeons did not respond to the survey despite reminder notifications. Additionally, the survey did not undergo rigorous principal components analysis nor assessed for internal consistency to prove internal validity. Finally, since our focus was on evaluating the use of systemic antibiotics, we did not capture the use of topical antibiotics.