Falkinham J O, Norton C D, LeChevallier M W
Fralin Biotechnology Center, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0346, USA.
Appl Environ Microbiol. 2001 Mar;67(3):1225-31. doi: 10.1128/AEM.67.3.1225-1231.2001.
Eight water distribution systems were sampled over an 18-month period (528 water and 55 biofilm samples) to measure the frequency of recovery and number of mycobacteria, particularly Mycobacterium avium and Mycobacterium intracellulare, in raw source waters before and after treatment and within the distribution system. The systems were chosen to assess the influence of source water, treatment, and assimilable organic carbon levels on mycobacterial numbers. Overall, mycobacterial recovery from the systems was low (15% of samples). Numbers of mycobacteria ranged from 10 to 700,000 CFU liter(-1). The number of M. avium in raw waters was correlated with turbidity. Water treatment substantially reduced the number of mycobacteria in raw waters by 2 to 4 log units. Mycobacterial numbers were substantially higher in the distribution system samples (average, 25,000-fold) than in those collected immediately downstream from the treatment facilities, indicating that mycobacteria grow in the distribution system. The increase in mycobacterial numbers was correlated with assimilable organic carbon and biodegradable organic carbon levels (r(2) = 0.65, P = 0.03). Although M. intracellulare was seldom recovered from water samples, it was frequently recovered (six of eight systems) in high numbers from biofilms (average, 600 CFU/cm(2)). Evidently, the ecological niches of M. avium and M. intracellulare are distinct.
在18个月的时间里，对8个供水系统进行了采样（共采集了528份水样和55份生物膜样本），以测定在处理前后以及配水系统中，原水源水中分枝杆菌，特别是鸟分枝杆菌和胞内分枝杆菌的检出频率和数量。选择这些系统是为了评估水源水、处理工艺以及可同化有机碳水平对分枝杆菌数量的影响。总体而言，从这些系统中分枝杆菌的检出率较低（样本的15%）。分枝杆菌数量在10至700,000 CFU/升之间。原水中鸟分枝杆菌的数量与浊度相关。水处理使原水中分枝杆菌的数量大幅减少了2至4个对数单位。配水系统样本中的分枝杆菌数量（平均为处理设施下游紧邻处采集样本的25,000倍）显著高于后者，这表明分枝杆菌在配水系统中生长。分枝杆菌数量的增加与可同化有机碳和可生物降解有机碳水平相关（r² = 0.65，P = 0.03）。虽然胞内分枝杆菌很少从水样中检出，但它经常（8个系统中有6个）从生物膜中大量检出（平均为600 CFU/cm²）。显然，鸟分枝杆菌和胞内分枝杆菌的生态位是不同的。
