Brown P E, Christensen O F, Clough H E, Diggle P J, Hart C A, Hazel S, Kemp R, Leatherbarrow A J H, Moore A, Sutherst J, Turner J, Williams N J, Wright E J, French N P
Department of Mathematics and Statistics, Lancaster University, Lancaster, United Kingdom.
Appl Environ Microbiol. 2004 Nov;70(11):6501-11. doi: 10.1128/AEM.70.11.6501-6511.2004.
Humans are exposed to Campylobacter spp. in a range of sources via both food and environmental pathways. For this study, we explored the frequency and distribution of thermophilic Campylobacter spp. in a 10- by 10-km square rural area of Cheshire, United Kingdom. The area contains approximately 70, mainly dairy, farms and is used extensively for outdoor recreational activities. Campylobacter spp. were isolated from a range of environmental samples by use of a systematic sampling grid. Livestock (mainly cattle) and wildlife feces and environmental water and soil samples were cultured, and isolates were presumptively identified by standard techniques. These isolates were further characterized by PCR. Campylobacter jejuni was the most prevalent species in all animal samples, ranging from 11% in samples from nonavian wildlife to 36% in cattle feces, and was isolated from 15% of water samples. Campylobacter coli was commonly found in water (17%) and sheep (21%) samples, but rarely in other samples. Campylobacter lari was recovered from all sample types, with the exception of sheep feces, and was found in moderate numbers in birds (7%) and water (5%). Campylobacter hyointestinalis was only recovered from cattle (7%) and birds (1%). The spatial distribution and determinants of C. jejuni in cattle feces were examined by the use of model-based spatial statistics. The distribution was consistent with very localized within-farm or within-field transmission and showed little evidence of any larger-scale spatial dependence. We concluded that there is a potentially high risk of human exposure to Campylobacter spp., particularly C. jejuni, in the environment of our study area. The prevalence and likely risk posed by C. jejuni-positive cattle feces in the environment diminished as the fecal material aged. After we took into account the age of the fecal material, the absence or presence of rain, and the presence of bird feces, there was evidence of significant variation in the prevalence of C. jejuni-positive cattle feces between grazing fields but no evidence of spatial clustering beyond this resolution. The spatial pattern of C. jejuni is therefore consistent with that for an organism that is ubiquitous in areas contaminated with cattle feces, with a short-scale variation in infection intensity that cannot be explained solely by variations in the age of the fecal material. The observed pattern is not consistent with large-scale transmission attributable to watercourses, wildlife territories, or other geographical features that transcend field and farm boundaries.
人类通过食物和环境途径接触多种来源的弯曲杆菌属细菌。在本研究中，我们探究了嗜热弯曲杆菌属细菌在英国柴郡一个10×10公里见方的农村地区的出现频率和分布情况。该地区约有70个农场，主要是奶牛场，并且广泛用于户外休闲活动。通过使用系统采样网格，从一系列环境样本中分离出弯曲杆菌属细菌。对家畜（主要是牛）和野生动物的粪便以及环境水和土壤样本进行培养，并采用标准技术对分离菌株进行初步鉴定。这些分离菌株通过聚合酶链反应（PCR）进一步鉴定。空肠弯曲杆菌是所有动物样本中最常见的菌种，在非禽类野生动物样本中的占比为11%，在牛粪中的占比为36%，并且从15%的水样中分离得到。结肠弯曲杆菌常见于水样（17%）和羊粪样本（21%）中，但在其他样本中很少见。海鸥弯曲杆菌从除羊粪外的所有样本类型中均有检出，在鸟类（7%）和水样（5%）中数量适中。猪肠弯曲杆菌仅从牛（7%）和鸟类（1%）样本中分离得到。利用基于模型的空间统计学方法研究了牛粪中空肠弯曲杆菌的空间分布及其影响因素。其分布与农场内或田间非常局部的传播一致，几乎没有证据表明存在任何更大规模的空间依赖性。我们得出结论，在我们研究区域的环境中，人类接触弯曲杆菌属细菌，尤其是空肠弯曲杆菌的潜在风险可能很高。随着粪便物质老化，环境中空肠弯曲杆菌阳性牛粪的流行率和可能带来的风险降低。在考虑粪便物质的年龄、是否下雨以及鸟类粪便的存在情况后，有证据表明不同放牧田地之间空肠弯曲杆菌阳性牛粪的流行率存在显著差异，但在此分辨率之上没有空间聚集的证据。因此，空肠弯曲杆菌的空间模式与在受牛粪污染地区普遍存在的一种微生物的模式一致，其感染强度存在小规模变化，而这种变化不能仅由粪便物质的年龄差异来解释。观察到的模式与由水道、野生动物领地或其他跨越田地和农场边界的地理特征导致的大规模传播不一致。
