Axelsson-Olsson Diana, Ellström Patrik, Waldenström Jonas, Haemig Paul D, Brudin Lars, Olsen Björn
Section for Zoonotic Ecology and Epidemiology, University of Kalmar, SE-391 82 Kalmar, Sweden.
Appl Environ Microbiol. 2007 Nov;73(21):6864-9. doi: 10.1128/AEM.01305-07. Epub 2007 Sep 14.
In this study, we present a novel method to isolate and enrich low concentrations of Campylobacter pathogens. This method, Acanthamoeba-Campylobacter coculture (ACC), is based on the intracellular survival and multiplication of Campylobacter species in the free-living protozoan Acanthamoeba polyphaga. Four of the Campylobacter species relevant to humans and livestock, Campylobacter jejuni, C. coli, C. lari, and C. hyointestinalis, were effectively enriched by the coculture method, with growth rates comparable to those observed in other Campylobacter enrichment media. Studying six strains of C. jejuni isolated from different sources, we found that all of the strains could be enriched from an inoculum of fewer than 10 bacteria. The sensitivity of the ACC method was not negatively affected by the use of Campylobacter-selective antibiotics in the culture medium, but these were effective in suppressing the growth of seven different bacterial species added at a concentration of 10(4) CFU/ml of each species as deliberate contamination. The ACC method has advantages over other enrichment methods as it is not dependent on a microaerobic milieu and does not require the use of blood or other oxygen-quenching agents. Our study found the ACC method to be a promising tool for the enrichment of Campylobacter species, particularly from water samples with low bacterial concentrations.
在本研究中，我们提出了一种分离和富集低浓度弯曲杆菌病原体的新方法。这种方法，即棘阿米巴-弯曲杆菌共培养（ACC），基于弯曲杆菌属在自由生活的原生动物多噬棘阿米巴中细胞内存活和繁殖。与人和牲畜相关的四种弯曲杆菌，空肠弯曲杆菌、大肠弯曲杆菌、海鸥弯曲杆菌和猪肠弯曲杆菌，通过共培养方法得到有效富集，其生长速率与在其他弯曲杆菌富集培养基中观察到的相当。研究从不同来源分离的六株空肠弯曲杆菌，我们发现所有菌株都可以从少于10个细菌的接种物中富集。ACC方法的敏感性不受培养基中弯曲杆菌选择性抗生素使用的负面影响，但这些抗生素有效地抑制了以10⁴CFU/ml的浓度作为故意污染添加的七种不同细菌物种的生长。ACC方法优于其他富集方法，因为它不依赖于微需氧环境，也不需要使用血液或其他氧气淬灭剂。我们的研究发现ACC方法是富集弯曲杆菌属的一种有前途的工具，特别是从细菌浓度低的水样中富集。
