Department of Clinical Sciences, Faculty of Veterinary Medicine, Université de Montréal, Montreal, Quebec, Canada.
Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Montreal, Quebec, Canada
Appl Environ Microbiol. 2019 Jun 17;85(13). doi: 10.1128/AEM.00037-19. Print 2019 Jul 1.
Ceftiofur, a third-generation cephalosporin antimicrobial, was used in Canadian hatcheries for many years to prevent early mortality in chicks, leading to a high prevalence of cephalosporin resistance in in chickens. Preventive use of ceftiofur in hatcheries ceased in 2014. We examined the effect of ceftiofur cessation ( = 40 flocks with ceftiofur and = 28 flocks without antimicrobial at hatchery) and its replacement with an antimicrobial combination, lincomycin-spectinomycin ( = 32), at the hatchery on the proportion of samples with positive for extended-spectrum-β-lactamase (ESBL) and AmpC β-lactamase-related genes, and on the multidrug resistance profiles of ESBL/AmpC-positive in broilers and their associated breeders ( = 46 samples), at 1 year postcessation. For indicator from nonenriched media, a significant decrease postcessation in the proportion of samples harboring isolates positive for and/or was observed. In contrast, following enrichment in medium containing ceftriaxone (1 mg/liter) to facilitate recovery of ESBL/AmpC β-lactamase-producing colonies, both pre- and postcessation, 99% of the samples harbored positive for or Among the 15 tested antimicrobial agents, flocks receiving lincomycin-spectinomycin after cessation of ceftiofur showed a significantly greater nonsusceptibility to aminoglycosides, folate inhibitors, phenicols, and tetracyclines and a greater proportion of possible extensively drug-resistant than those receiving ceftiofur or no antimicrobial at hatchery. This study clearly demonstrates an initial decrease in ESBL/AmpC-positive following the cessation of ceftiofur in the hatchery but an increase in antimicrobial non-β-lactam resistance of ESBL/AmpC-positive following replacement with lincomycin-spectinomycin. Antimicrobial resistance is a global problem. The antimicrobial ceftiofur has been used worldwide for disease prevention in poultry production, resulting in a greatly increased resistance to this antimicrobial important in poultry and human medicine. Our study examined the impact of ceftiofur cessation and its replacement with the antimicrobial combination lincomycin-spectinomycin, a common practice in the industry. Our study demonstrated a decrease in ceftiofur resistance after the cessation of ceftiofur use, although the resistance genes remain ubiquitous in all phases of poultry production, showing that poultry remains a reservoir for ceftiofur resistance and requiring continued vigilance. We also observed a decrease in multidrug resistance involving different antimicrobial classes after cessation of ceftiofur but an increase following use of lincomycin-spectinomycin, indicating that this antimicrobial use should be questioned. Reduced resistance to ceftiofur in poultry may translate to better treatment efficacy, decreased morbidity/mortality, and enhanced food safety for humans.
头孢噻呋是一种第三代头孢菌素类抗菌药物，多年来在加拿大孵化场用于预防雏鸡早期死亡，导致鸡群中头孢菌素类耐药率很高。2014 年，孵化场停止预防性使用头孢噻呋。我们研究了孵化场停止使用头孢噻呋（ = 40 个使用头孢噻呋的鸡群和 = 28 个没有使用抗菌药物的鸡群）及其用抗菌药物组合林可霉素-壮观霉素（ = 32）替代对鸡群中 携带扩展谱β-内酰胺酶（ESBL）和 AmpC β-内酰胺酶相关基因的样本比例的影响，以及对 1 年后停止使用头孢噻呋后 ESBL/AmpC 阳性鸡和其相关种鸡（ = 46 个样本）的多药耐药谱的影响。对于非富集培养基中的指示菌，观察到停止使用头孢噻呋后，携带 分离株阳性的样本中 阳性和/或 阳性的比例显著下降。相比之下，在含有头孢曲松（1 mg/L）的培养基中进行富集以促进 ESBL/AmpC β-内酰胺酶产生 分离株的回收后，无论是在停止使用头孢噻呋之前还是之后，99%的样本都携带 阳性的 或 。在测试的 15 种抗菌药物中，停止使用头孢噻呋后接受林可霉素-壮观霉素的鸡群对氨基糖苷类、叶酸抑制剂、酚类和四环素的非敏感性显著增加，并且可能对广泛耐药的 比例增加比那些在孵化场接受头孢噻呋或没有抗菌药物的鸡群更大。本研究清楚地表明，孵化场停止使用头孢噻呋后，ESBL/AmpC 阳性的 数量最初减少，但用林可霉素-壮观霉素替代后，ESBL/AmpC 阳性的 对非β-内酰胺类抗菌药物的耐药性增加。抗菌药物耐药性是一个全球性问题。抗菌药物头孢噻呋已在全球范围内用于家禽生产中的疾病预防，导致对这种在禽医和人医中非常重要的抗菌药物的耐药性大大增加。我们的研究检查了停止使用头孢噻呋及其用抗菌药物组合林可霉素-壮观霉素替代的影响，这是该行业的常见做法。我们的研究表明，停止使用头孢噻呋后，头孢噻呋耐药性有所下降，尽管耐药基因仍然存在于家禽生产的所有阶段，表明家禽仍然是头孢噻呋耐药性的储存库，需要持续保持警惕。我们还观察到停止使用头孢噻呋后涉及不同抗菌药物类别的多药耐药性下降，但使用林可霉素-壮观霉素后增加，表明应质疑这种抗菌药物的使用。家禽对头孢噻呋的耐药性降低可能转化为更好的治疗效果、降低发病率/死亡率以及提高人类食品安全。
