Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
J Dairy Sci. 2010 Jan;93(1):105-14. doi: 10.3168/jds.2009-2299.
The use of pathogenic-specific antimicrobials, as proposed by bacteriophage therapy, is expected to reduce the incidence of resistance development. Eighty Escherichia coli isolated from uteri of Holstein dairy cows were phenotypically characterized for antimicrobial resistance to ampicillin, ceftiofur, chloramphenicol, florfenicol, spectinomycin, streptomycin, and tetracycline by broth microdilution method. The lytic activity of a bacteriophage cocktail against all isolates was performed by a similar method. Additionally, the effect of different concentrations of antimicrobials and multiplicities of infections (MOI) of the bacteriophage cocktail on E. coli growth curve was measured. Isolates exhibited resistance to ampicillin (33.7%), ceftiofur (1.2%), chloramphenicol (100%), and florfenicol (100%). All strains were resistant to at least 2 of the antimicrobial agents tested; multidrug resistance (>or=3 of 7 antimicrobials tested) was observed in 35% of E. coli isolates. The major multidrug resistance profile was found for ampicillin-chloramphenicol-florfenicol, which was observed in more than 96.4% of the multidrug-resistant isolates. The bacteriophage cocktail preparation showed strong antimicrobial activity against multidrug-resistant E. coli. Multiplicity of infection as low as 10(-4) affected the growth of the E. coli isolates. The ratio of 10 bacteriophage particles per bacterial cell (MOI=10(1)) was efficient in inhibiting at least 50% of all isolates. Higher MOI should be tested in future in vitro studies to establish ratios that completely inhibit bacterial growth during longer periods. All isolates resistant to florfenicol were resistant to chloramphenicol and, because florfenicol was recently introduced into veterinary clinics, this finding suggests that the selection pressure of chloramphenicol, as well as other antimicrobials, may still play a relevant role in the emergence and dissemination of florfenicol resistance in E. coli. The bacteriophage cocktail had a notable capacity to inhibit the in vitro growth of E. coli isolates, and it may be an attractive alternative to conventional treatment of metritis by reducing E. coli in uteri of postpartum dairy cows.
利用噬菌体治疗提出的针对病原体的抗菌药物有望降低耐药性的发生率。通过肉汤微量稀释法对从荷斯坦奶牛子宫中分离出的 80 株大肠杆菌进行了对氨苄青霉素、头孢噻呋、氯霉素、氟苯尼考、壮观霉素、链霉素和四环素的表型耐药性特征分析。通过类似的方法测定了噬菌体混合物对所有分离株的溶菌活性。此外，还测量了不同浓度的抗菌药物和噬菌体混合物的感染复数（MOI）对大肠杆菌生长曲线的影响。分离株对氨苄青霉素（33.7%）、头孢噻呋（1.2%）、氯霉素（100%）和氟苯尼考（100%）均表现出耐药性。所有菌株均对至少 2 种测试的抗菌药物具有耐药性；35%的大肠杆菌分离株表现出多药耐药性（测试的 7 种抗菌药物中至少 3 种耐药）。最主要的多药耐药谱是氨苄青霉素-氯霉素-氟苯尼考，超过 96.4%的多药耐药分离株表现出这种耐药谱。噬菌体混合物制剂对多药耐药性大肠杆菌具有很强的抗菌活性。感染复数低至 10(-4)就会影响大肠杆菌分离株的生长。每 1 个细菌细胞 10 个噬菌体颗粒的比例（MOI=10(1)）能够有效抑制至少 50%的所有分离株。在未来的体外研究中应测试更高的 MOI，以确定在更长时间内完全抑制细菌生长的比例。所有对氟苯尼考耐药的分离株均对氯霉素耐药，由于氟苯尼考最近被引入兽医临床，这一发现表明，氯霉素以及其他抗菌药物的选择压力可能仍然在大肠杆菌中氟苯尼考耐药性的出现和传播中发挥着重要作用。噬菌体混合物对大肠杆菌分离株的体外生长具有显著的抑制能力，它可能是减少产后奶牛子宫内大肠杆菌数量从而降低子宫内膜炎传统治疗方法的一种有吸引力的替代方法。
Appl Environ Microbiol. 2006-6
J Antimicrob Chemother. 2006-6
Appl Environ Microbiol. 2007-1
Antibiotics (Basel). 2021-5-11
Front Microbiol. 2015-8-19
Zotero 插件