The increasing resistance to antibiotics is compromising the empirical treatment of infections caused by resistant bacteria. Rapid, efficient, and clinically applicable phenotypic methods are needed for their detection. This study examines the phenotypic behavior of β-lactam-resistant Gram-negative bacteria grown on ChromID ESBL medium with ertapenem, cefoxitin, and cefepime disks, reports on the coloration of colonies, and establishes a halo diameter breakpoint for the detection of carbapenemase-producing bacteria. We studied 186 β-lactam-resistant Gram-negative microorganisms (77 with extended spectrum beta lactamase (ESBL), 97 with carbapenemases, and 12 with AmpC β-lactamases (AmpC)). Susceptibility profiles of Gram-negative bacteria that produced ESBL, AmpC, and carbapenemases were similar to the expected profiles, with some differences in the response to cefepime of ESBL-producing microorganisms. Coloration values did not differ from those described by the manufacturer of ChromID ESBL medium. In the screening of carbapenemase production, inhibition halo diameter breakpoints for antibiotic resistance were 18 mm for Enterobacterales and ertapenem, 18 mm for Pseudomonas and cefepime, and 16 mm for Acinetobacter baumannii and cefepime. This innovative phenotypic approach is highly relevant to clinical laboratories, combining susceptibility profiles with detection by coloration of high-priority resistant microorganisms such as carbapenemase-producing A. baumannii, carbapenemase-producing Pseudomonas spp., and ESBL and/or carbapenemase-producing Enterobacterales.

中文翻译：

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抗生素敏感性谱筛选对β-内酰胺类抗生素耐药的革兰氏阴性菌的临床相关性

对抗生素的抵抗力的增强正在损害由耐药菌引起的感染的经验性治疗。需要快速，有效和临床应用的表型方法进行检测。这项研究检查了在带有ertapenem，cefoxitin和cefepime圆片的ChromID ESBL培养基上生长的β-内酰胺抗性革兰氏阴性细菌的表型行为，报告了菌落的颜色，并建立了晕轮直径转折点，用于检测碳青霉烯酶的产生菌。我们研究了186种抗β-内酰胺的革兰氏阴性微生物（77种具有广谱β-内酰胺酶（ESBL），97种具有碳青霉烯酶和12种具有AmpCβ-内酰胺酶（AmpC））。产生ESBL，AmpC和碳青霉烯酶的革兰氏阴性菌的敏感性分布与预期的相似，与产生ESBL的微生物对头孢吡肟的反应有些不同。色度值与ChromID ESBL培养基制造商描述的色度值没有差异。在筛选碳青霉烯酶的过程中，抗生素耐药性的抑制晕圈直径断裂点为18 mm肠杆菌和厄他培南，假单胞菌和头孢吡肟为18毫米，鲍曼不动杆菌和头孢吡肟为16毫米。这种创新的表型方法与临床实验室高度相关，将敏感性分布与通过对高优先级耐药微生物（如产生碳青霉烯酶的鲍曼不动杆菌，产生碳青霉烯酶的假单胞菌属，ESBL和/或产生碳青霉烯酶的肠杆菌）的着色进行检测相结合。