Smith L D
Appl Microbiol. 1975 May;29(5):590-4. doi: 10.1128/am.29.5.590-594.1975.
A relatively rich medium was markedly superior to a dilute medium for the isolation of anaerobic bacteria from soil. The obligate anaerobes isolated from 21 soil samples were all clostridia and the counts ranged from 2.7 X 10-2 to 3.3 X 10-6 per g. The organisms most frequently isolated were Clostridium subterminate, C. sordelii, C. sporogenes, C. indolis, C. bifermentans, C. mangenoti, and C. perfringens. Seventeen other species were also recognized but almost one-third of the isolates could not be identified with any known species of Clostridium. C. botulinum type A was demonstrated in six soil samples, and type B in one. These soils were neutral to alkaline in reaction (average pH 7.9) and low in organic matter content (1.4%). The association of C. botulinum types A and B with neutral to alkaline soils was statistically significant (P = 0.001) as was their association with soils low in organic matter (P = 0.005). C. botulinum types E and F were found in one soil sample, pH 4.5, with organic matter 13.7%. C. tetani was isolated from two soil samples, both of intermediate pH value and higher than average organic matter content.
在从土壤中分离厌氧菌时，相对丰富的培养基明显优于稀释培养基。从21个土壤样本中分离出的专性厌氧菌均为梭菌属，计数范围为每克2.7×10⁻²至3.3×10⁻⁶。最常分离出的菌株为次端芽孢梭菌、索氏梭菌、产芽孢梭菌、吲哚梭菌、双发酵梭菌、曼氏梭菌和产气荚膜梭菌。还识别出了其他17个物种，但几乎三分之一的分离株无法与任何已知的梭菌属物种鉴定。在6个土壤样本中检测到A型肉毒梭菌，在1个样本中检测到B型。这些土壤反应呈中性至碱性（平均pH值7.9），有机质含量低（1.4%）。A型和B型肉毒梭菌与中性至碱性土壤的关联具有统计学意义（P = 0.001），它们与低有机质土壤的关联也具有统计学意义（P = 0.005）。在一个pH值为4.5、有机质含量为13.7%的土壤样本中发现了E型和F型肉毒梭菌。从两个土壤样本中分离出破伤风梭菌，这两个样本的pH值均处于中等水平，且有机质含量高于平均水平。
