Jacob Megan E, Keelara Shivaramu, Aidara-Kane Awa, Matheu Alvarez Jorge R, Fedorka-Cray Paula J
Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
Department of Food Safety and Zoonosis, World Health Organization (WHO), Geneva, Switzerland.
J Clin Microbiol. 2020 Aug 24;58(9). doi: 10.1128/JCM.01039-19.
The increasing prevalence of extended-spectrum beta-lactamase (ESBL)-producing is worrisome. Coordinated efforts to better understand global prevalence and risk factors are needed. Developing lower- and middle-income countries need reliable, readily available, and cost-effective solutions for detecting ESBL to contribute to global surveillance. We evaluated MacConkey agar supplemented with ceftriaxone or cefotaxime as a screening method for accurately detecting and quantifying potential ESBL MacConkey agar from eight manufacturers, representing seven countries, was prepared with 2 or 4 μg/ml ceftriaxone or cefotaxime. Four strains (NC11, ATCC 25922, CM-13457, and CM-10455) and one strain (CM-11073) were grown overnight, serially diluted, and plated in triplicate for enumeration on all medium combinations. After recovery was assessed, US-1 MacConkey agar with cefotaxime was used to further evaluate the reproducibility and detection of potential ESBL from poultry cecal ( = 30) and water ( = 30) samples. Results indicated the recovery of 13457 from four MacConkey agar manufacturers was reduced by up to 4 log CFU/ml, and phenotypic differences in colony size and color were apparent for each manufacturer for control strains. A true ESBL, NC11, was not reduced with 4 μg/ml cefotaxime. From ceca and water, potential ESBL isolates were only confirmed from MacConkey agar with 4 μg/ml cefotaxime, where 45% and 16.6% of isolates phenotypically expressed ESBL production. The quality and reproducibility of MacConkey agar varied by manufacturer, which suggests that a single manufacturer and medium type should be selected for global monitoring efforts so that training and interpretation can be standardized.
产超广谱β-内酰胺酶（ESBL）细菌的日益流行令人担忧。需要开展协同努力，以更好地了解全球流行情况和风险因素。中低收入国家需要可靠、易于获得且具有成本效益的ESBL检测解决方案，以促进全球监测。我们评估了添加头孢曲松或头孢噻肟的麦康凯琼脂作为准确检测和定量潜在ESBL的筛查方法。制备了来自七个国家八个制造商的麦康凯琼脂，添加2或4μg/ml头孢曲松或头孢噻肟。将四株大肠杆菌（NC11、ATCC 25922、CM-13457和CM-10455）和一株肺炎克雷伯菌（CM-11073）过夜培养，进行系列稀释，并一式三份接种于所有培养基组合上进行计数。评估恢复情况后，使用添加头孢噻肟的US-1麦康凯琼脂进一步评估来自家禽盲肠（n = 30）和水（n = 30）样本中潜在ESBL的重现性和检测情况。结果表明，来自四个麦康凯琼脂制造商的CM-13457回收率降低了高达4 log CFU/ml，每个制造商的对照菌株在菌落大小和颜色上存在明显的表型差异。真正的ESBL菌株NC11在4μg/ml头孢噻肟存在下未减少。从盲肠和水中，仅在添加4μg/ml头孢噻肟的麦康凯琼脂上确认了潜在的ESBL分离株，其中45%和16.6%的分离株在表型上表达ESBL产生。麦康凯琼脂的质量和重现性因制造商而异，这表明应选择单一制造商和培养基类型进行全球监测工作，以便培训和解释能够标准化。
