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Previous studies from this laboratory have documented the presence of coliform bacteria emanating from wooden reservoirs containing finished drinking water. Coliforms were identified as Klebsiella pneumoniae and Enterobacter spp. In the present report, evidence is presented which suggests that the origin of these coliforms is from the wood used to construct the reservoirs. In liquid expressed from freshly cut redwood, total bacterial counts in the range of 105 to 106/ml were commonly observed. When present, coliform counts were over 103/ml of expressed liquid. E. agglomerans was the most prevalent coliform present, but Klebsiella was isolated from freshly cut logs. Citrobacter freundii was also occasionally isolated. No fecal coliform-positive Klebsiella were obtained from any of the samples. Highest total bacteria and coliform counts were observed in sapwood specimens. Coliforms were present throughout sapwood as evidenced by contact plating serial sections of freshly cut wood. Scanning electron micrographs illustrate the presence of bacterial colonies within sapwood tracheids. Other wood species also contained coliform bacteria but in numbers lower than found in redwood.

Bacteria of the tribe Klebsielleae are capable of metabolizing the cycitols myoinositol, sequoyitol, and pinitol, which are present in aqueous extracts of redwood. Of the combined Klebsiella isolates from clinical and environmental origins, 100% (138/138), 97% (34/35), and 86% (119/138) fermented inositol, sequoyitol, and pinitol, respectively. These compounds were also used as a sole source of carbon and energy by Klebsiella. Similar results were obtained with Enterobacter

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A total of 183 isolates of Klebsiella from drinking water, market vegetables, wood, sawdust, industrial effluents, and human and animal origin were examined for susceptibility to 10 antibacterial agents. Incidence of resistance to two or more antibiotics tested was: 65% of the human clinical isolates, 59% among bovine mastitis, and 24% among the nonclinical isolates. The five different multiple resistance patterns among nonclinically derived Klebsiella were also found among the human and bovine mastitis isolates. Statistical analyses revealed that patterns of resistance among Klebsiella isolates from drinking water, market vegetables, and industrial effluents were highly correlated with each other and with resistance patterns of human clinical isolates. Antibiotic resistance was transferred between Klebsiella growing in two habitat-simulated environments (growing radish plants and aqueous sawdust suspensions). Transconjugants were detected in 5 of 21 and 6 of 21 mating pairs, respectively. Average transconjugants/donor ranged from