Effect of intravenous or oral sodium chlorate administration on the fecal shedding of Escherichia coli in sheep

Detection of chlorite, chlorate and perchlorate in ozonated saline

Medical ozone is used to treat various diseases, including numerous pathologies associated with chronic pain. Chronic pain may be treated by systemic administration of ozone, with ozonated autohemotherapy (OAH) being the commonly used method. In the clinic, intravenous infusion of ozonized saline has been used to treat various diseases. Compared with OAH, ozonized saline infusion is less technically demanding and causes minimal damage to veins. However, it has been indicated that ozone may oxidize saline and generate toxic substances, and therefore, the safety of ozone treatment has been questioned. In the present study, the potential chemical compounds produced from ozone and saline, including chlorite, chlorate and perchlorate, were examined at various time-points with ion chromatography-mass spectrometry (IC-MS). A control group (pure oxygen group) and an ozone group were included in the present study. Two subgroups were included within each group: A saline bottle (made from polypropylene) subgroup and an ozone-resistant blood transfusion bag [made from medical polyvinyl chloride, di(2-ethyl) hexyl phthalate plasticized] subgroup. For the ozone group, 100 ml saline and 100 ml medical ozone at various concentrations (20, 40 or 60 µg/ml in pure oxygen) were injected into the saline bottle or blood bag, and for the control group, 100 ml of pure oxygen was injected into the saline bottle or blood bag. The presence and the content of chlorite, chlorate and perchlorate were determined at different time-points (3, 6 and 15 days after mixing) by IC-MS. Chlorate was detected in the ozone groups at three time-points and its content increased as the ozone concentration and the reaction time increased. Under the same conditions (the same ozone concentration and the same incubation time), the chlorate content (0.90±0.14-7.69±0.48 µg/l) in the blood bag subgroup was significantly lower than that in the saline bottle subgroup (45.23±6.14-207.6±15.63 µg/l). However, chlorite and perchlorate were not detected at any time-point in the two groups. In addition, in the control group (pure oxygen group), chlorite, chlorate and perchlorate were not detected at any time-point. These results indicate that ozone reacts with saline to produce chlorate. Ozone may also react with the polypropylene saline bottle to increase the chlorate content in the bottled solution. Due to a lack of toxicology studies of chlorate in blood, it remains elusive whether ozonated saline and chlorate at the range of 0.90±0.14-7.69±0.48 µg/l has any toxic effects. The potential toxicity of chlorate should be considered when ozonated saline is used for clinical infusions.

Continuous, low-dose oral exposure to sodium chlorate reduces fecal generic Escherichia coli in sheep feces without inducing clinical chlorate toxicosis

Our objectives were to determine an effective, yet safe, daily dose of sodium chlorate for reducing fecal shedding of generic Escherichia coli in mature ewes. In a completely randomized experimental design, 25 Targhee ewes (age ∼ 18 mo; BW = 62.5 ± 7.3 kg, mean ± SD) were assigned randomly to 1 of 5 sodium chlorate treatments, which were administered in the drinking water for 5 consecutive days. Treatments were control group (no sodium chlorate) and 4 targeted levels of daily sodium chlorate intake: 30, 60, 90, and 120 mg · kg(-1) BW · d(-1) for 5 d. Individual ewe ad libitum intake of water (with treatments) was measured daily, and BW was measured at the beginning of and 15 and 51 d after the 5-d treatment period. Serum chlorate, whole blood methemoglobin and packed-cell volume (PCV), and fecal generic E. coli and general Enterobacteriaceae coliforms were measured from corresponding samples collected at the end of the 5-d treatment period. Average daily intakes of sodium chlorate from drinking water treatments were 95%, 91%, 90%, and 83% of the target treatment intakes of 30, 60, 90, and 120 mg · kg(-1) BW · d(-1), respectively. Daily sodium chlorate intake remained constant for all treatment groups except for ewes offered 120 mg NaClO3 · kg(-1) BW · d(-1), which decreased (quadratic; P = 0.04) over the course of the 5-d treatment period. This decrease in sodium chlorate intake indicated that the 120-mg NaClO3 level may have induced either toxicity and/or an aversion to the drinking water treatment. Serum chlorate concentrations increased (quadratic; P < 0.001) with increasing sodium chlorate intake. At the end of the 5-d treatment period, mean (least squares ± SEM) serum chlorate concentrations for ewes offered 30, 60, 90, and 120 mg NaClO3 · kg(-1) BW · d(-1) were 15.6 ± 14.1, 32.8 ± 15.8, 52.9 ± 14.1, and 90.3 ± 14.1 μg/mL, respectively. Whole blood methemoglobin and PCV were similar (P = 0.31 to 0.81) among the control group and ewes offered sodium chlorate. Likewise, BW was not affected by sodium chlorate (P > 0.27). Ewes consuming approximately 55 mg NaClO3 · kg(-1) BW · d(-1) or more (i.e., ewes offered 60, 90, and 120 mg) had a >1.4 log unit reduction in fecal E. coli and Enterobacteriaceae coliforms compared with control ewes. We suggest that for a short-term, 5-d dosing strategy, 55 to 81 mg NaClO3 · kg(-1) BW · d(-1) is an effective, yet safe, daily oral dose range for mature ewes to achieve a 97% to 99% reduction in fecal shedding of generic E. coli.