Department of Pharmacy, University of Tromsø, 9037 Tromsø, Norway.
BMC Microbiol. 2010 Jan 14;10:10. doi: 10.1186/1471-2180-10-10.
Polar bears (Ursus maritimus) are major predators in the Arctic marine ecosystem, feeding mainly on seals, and living closely associated with sea ice. Little is known of their gut microbial ecology and the main purpose of this study was to investigate the microbial diversity in faeces of polar bears in Svalbard, Norway (74-81 degrees N, 10-33 degrees E). In addition the level of blaTEM alleles, encoding ampicillin resistance (ampr) were determined. In total, ten samples were collected from ten individual bears, rectum swabs from five individuals in 2004 and faeces samples from five individuals in 2006.
A 16S rRNA gene clone library was constructed, and all sequences obtained from 161 clones showed affiliation with the phylum Firmicutes, with 160 sequences identified as Clostridiales and one sequence identified as unclassified Firmicutes. The majority of the sequences (70%) were affiliated with the genus Clostridium. Aerobic heterotrophic cell counts on chocolate agar ranged between 5.0 x 10(4) to 1.6 x 10(6) colony forming units (cfu)/ml for the rectum swabs and 4.0 x 10(3) to 1.0 x 10(5) cfu/g for the faeces samples. The proportion of ampr bacteria ranged from 0% to 44%. All of 144 randomly selected ampr isolates tested positive for enzymatic beta-lactamase activity. Three % of the ampr isolates from the rectal samples yielded positive results when screened for the presence of blaTEM genes by PCR. BlaTEM alleles were also detected by PCR in two out of three total faecal DNA samples from polar bears.
The bacterial diversity in faeces from polar bears in their natural environment in Svalbard is low compared to other animal species, with all obtained clones affiliating to Firmicutes. Furthermore, only low levels of blaTEM alleles were detected in contrast to their increasing prevalence in some clinical and commensal bacterial populations.
北极熊（Ursus maritimus）是北极海洋生态系统中的主要捕食者，主要以海豹为食，与海冰密切相关。关于它们肠道微生物生态的了解甚少，本研究的主要目的是调查挪威斯瓦尔巴群岛（北纬 74-81 度，东经 10-33 度）北极熊粪便中的微生物多样性。此外，还测定了编码氨苄青霉素抗性（ampr）的 blaTEM 等位基因的水平。总共从 10 只熊中采集了 10 个样本，2004 年从 5 只个体的直肠拭子和 2006 年从 5 只个体的粪便样本中采集。
构建了 16S rRNA 基因克隆文库，从 161 个克隆中获得的所有序列均与厚壁菌门（Firmicutes）有关，其中 160 个序列鉴定为梭状芽孢杆菌（Clostridiales），一个序列鉴定为未分类的厚壁菌门。大多数序列（70%）与梭状芽孢杆菌属（Clostridium）有关。巧克力琼脂上的需氧异养细胞计数范围为直肠拭子的 5.0×10(4)至 1.6×10(6)个菌落形成单位（cfu）/ml，粪便样本的 4.0×10(3)至 1.0×10(5) cfu/g。ampr 细菌的比例范围为 0%至 44%。随机选择的 144 个 ampr 分离株中，有 144 个经酶β-内酰胺酶活性检测均为阳性。当通过 PCR 筛选直肠样本中 blaTEM 基因的存在时，144 个 ampr 分离株中有 3%呈阳性结果。通过 PCR 还在 3 只北极熊的总粪便 DNA 样本中的 2 只样本中检测到 blaTEM 等位基因。
与其他动物物种相比，在斯瓦尔巴特群岛自然环境中北极熊粪便中的细菌多样性较低，所有获得的克隆均与厚壁菌门有关。此外，与某些临床和共生细菌种群中 blaTEM 等位基因的日益流行相比，检测到的 blaTEM 等位基因水平较低。
