Jun Hyunwoo, Scott-Thomas Amy, Slow Sandy, Williman Jonathan, Murdoch David R, Chambers Stephen T
Department of Pathology and Biomedical Science, University of Otago, Christchurch 8011, New Zealand.
Department of Agricultural Sciences, Lincoln University, Lincoln 7674, New Zealand.
Lett Appl Microbiol. 2023 Jul 3;76(7). doi: 10.1093/lambio/ovad074.
Legionella longbeachae is an important cause of Legionnaires' disease in Australasia and is associated with exposure to potting soils. Our aim was to identify ways to reduce the load of L. longbeachae in potting soils. Inductively-coupled plasma optical emission spectrometry (ICP-OES) of an all-purpose potting mix showed copper (Cu) concentrations (mg/kg) range from 15.8 to 23.6. Zinc (Zn) and manganese (Mn) were significantly higher than Cu ranging from 88.6-106 to 171-203, respectively. Minimal inhibitory and bactericidal concentrations of 10 salts used in the horticultural industry were determined for Legionella species in buffered yeast extract (BYE) broth. For L. longbeachae (n = 9) the median (range) minimum inhibitory concentration (MIC) (mg/L) of copper sulfate was 31.25 (15.6-31.25), zinc sulfate 31.25 (7.81-31.25), and manganese sulfate 31.25 (7.81-62.5). The MIC and minimum bactericidal concentration (MBC) were within one dilution of each other. Susceptibility to Cu and Zn salts increased as the concentration of pyrophosphate iron in the media decreased. The MIC values for these three metals against Legionella pneumophila (n = 3) and Legionella micdadei (n = 4) were similar. Combinations of Cu, Zn, and Mn were additive. Legionella longbeachae has similar susceptibility to Cu and other metal ions in comparison to L. pneumophila.
长滩军团菌是澳大利亚和新西兰地区军团病的一个重要病因，与接触盆栽土有关。我们的目标是找出降低盆栽土中长滩军团菌负荷的方法。对一种通用盆栽混合料进行电感耦合等离子体发射光谱法（ICP - OES）分析，结果显示铜（Cu）浓度（mg/kg）在15.8至23.6之间。锌（Zn）和锰（Mn）显著高于铜，分别在88.6 - 106和171 - 203之间。测定了园艺行业使用的10种盐在缓冲酵母提取物（BYE）肉汤中对军团菌属的最低抑菌浓度和杀菌浓度。对于长滩军团菌（n = 9），硫酸铜的最低抑菌浓度（MIC）（mg/L）中位数（范围）为31.25（15.6 - 31.25），硫酸锌为31.25（7.81 - 31.25），硫酸锰为31.25（7.81 - 62.5）。MIC和最低杀菌浓度（MBC）相差一个稀释度。随着培养基中亚铁焦磷酸盐浓度降低，对铜盐和锌盐的敏感性增加。这三种金属对嗜肺军团菌（n = 3）和米克戴德军团菌（n = 4）的MIC值相似。铜、锌和锰的组合具有相加作用。与嗜肺军团菌相比，长滩军团菌对铜和其他金属离子的敏感性相似。
