Charles M K, Wang Y, Zurberg T, Kinna J, Bryce E
Division of Medical Microbiology and Infection Prevention, Vancouver Coastal Health and University of British Columbia Faculty of Medicine, Vancouver, British Columbia, Canada.
University of British Columbia Undergraduate Integrated Sciences Program, Vancouver, British Columbia, Canada.
Infect Prev Pract. 2019 Apr 13;1(1):100005. doi: 10.1016/j.infpip.2019.100005. eCollection 2019 Mar.
Trained canines are capable of detecting (CD) in the environment; however, the primary odour of interest on which the dogs alert is unclear.
To evaluate the inter-rater reliability of two canine detection teams for their ability to discriminate between scent pads containing CD-toxin-positive and -negative odours and their ability to discriminate between clostridial strains.
During a six-month period, two canine teams were tested weekly for their ability to detect CD-toxin-positive odours and discriminate between these and -negative odours. To further determine the canines' discrimination capability, scent pads impregnated with odours from reference isolates representing common CD toxin types (including toxin-negative CD isolates) or from clinical isolates representing other clostridial species were used.
A total of 264 samples were tested with an overall sensitivity of 94.7% (Team A) and 86.8% (Team B) and specificities of 96.9% and 98.7%, respectively. Inter-rater reliability was very good (Cohen's kappa 0.87). When challenged with toxin- and non-toxin-producing strains, the teams alerted on 96.3% of all CD isolate odours (including nontoxigenic strains) and 46.7% of closely related species.
The canine teams exhibited strong inter-rater reliability on both clinical faecal specimens and reference CD isolates (both toxin and non-toxin producing) but were challenged to discriminate between CD and closely related clostridial species. These findings strongly support the development of scent detection programmes provided dogs and their handlers are properly trained and used in the right context.
经过训练的犬类能够检测环境中的艰难梭菌（CD）；然而，犬类发出警报所依据的主要目标气味尚不清楚。
评估两个犬类检测小组在区分含有CD毒素阳性和阴性气味的气味垫以及区分梭菌菌株方面的评分者间信度。
在六个月的时间里，每周对两个犬类小组进行测试，评估它们检测CD毒素阳性气味以及区分阳性和阴性气味的能力。为了进一步确定犬类的辨别能力，使用了浸渍有代表常见CD毒素类型的参考分离株（包括毒素阴性CD分离株）或代表其他梭菌物种的临床分离株气味的气味垫。
共测试了264个样本，总体敏感性分别为94.7%（A组）和86.8%（B组），特异性分别为96.9%和98.7%。评分者间信度非常好（科恩kappa系数为0.87）。当面对产毒素和不产毒素的菌株时，两个小组对所有CD分离株气味（包括不产毒素的菌株）的警觉率为96.3%，对密切相关物种的警觉率为46.7%。
犬类小组在临床粪便标本和参考CD分离株（产毒素和不产毒素的）上均表现出很强的评分者间信度，但在区分CD和密切相关的梭菌物种方面面临挑战。这些发现有力地支持了气味检测项目的开展，前提是犬类及其训练者要得到适当的训练并在合适的环境中使用。
