Induction of the viable but nonculturable state in Clavibacter michiganensis subsp. michiganensis and in planta resuscitation of the cells on tomato seedlings

Bacterial canker of tomato is an economically important seedborne disease caused by Clavibacter michiganensis subsp. michiganensis (Cmm). Copper‐based bactericides and seed treatment with hydrochloric acid are commonly used for bacterial canker management. Recent studies have shown that some bacteria can enter a viable but nonculturable (VBNC) state, and fail to form colonies on microbiological agar media. Bacteria in the VBNC state can recover their culturability when returned to favourable conditions. This study reports the induction of the VBNC state in Cmm by CuSO₄ and low pH, and resuscitation of VBNC cells on tomato seedlings. Flow cytometry using the nucleic acid dyes SYTO 9 and propidium iodide, combined with agar plating, was used to assess VBNC cell counts. It was demonstrated that CuSO₄ and low pH induced the VBNC state in Cmm and the rate of induction increased with copper ion concentration and acidity. Pathogenicity tests showed that some of the VBNC cells induced by CuSO₄ retained their ability to colonize tomato seedlings but failed to produce typical bacterial canker symptoms by 2 months post‐inoculation. This was probably due to low levels of resuscitation of VBNC Cmm cells resulting in low levels of initial inoculum. This study has improved understanding of the VBNC state of Gram‐positive phytopathogenic bacteria. Most importantly, because copper‐based chemicals and low pH conditions are used for disease management, induction of the VBNC state and subsequent resuscitation of Cmm cells on tomato seedlings may limit pathogen detection by culture‐based assays yet present a risk for disease development in the field.     

Effects of early liquid resuscitation combined with hydrogen inhalation on lung injury in septic shock rats induced by lipopolysaccharides

AIM：To study the effects of fluid resuscitation combined with 2% hydrogen inhalation on lung injury in septic shock rats induced by lipopolysaccharides (LPS). METHODS：Sixty male Wistar rats were randomized to 4 groups： normal control group, septic shock control group, fluid resuscitation group and fluid resuscitation plus hydrogen inhalation group. Liquid resuscitation was applied to the rats in fluid resuscitation group and fluid resuscitation plus hydrogen inhalation group. The rats in fluid resuscitation plus hydrogen inhalation group also received 2% hydrogen inhalation and the rats in other groups inhaled air for control. The pathological changes of the lung were observed under light microscope. The levels of inflammatory mediators in bronchoalveolar lavage fluid (BALF) were measured by ELISA. The expression of Fas and Bcl-2 was detected by Western blotting. RESULTS：Compared with fluid resuscitation group, the levels of inflammatory mediators in BALF and the expression of Fas in lung tissues were decreased, and the expression of Bcl-2 in lung tissue was increased in fluid resuscitation plus hydrogen inhalation group. CONCLUSION：Fluid resuscitation with 2% hydrogen inhalation exhibits a protective effect on lung injury induced by LPS.     

Use of Renal Replacement Therapy in a Neonatal Foal with Postresuscitation Acute Renal Failure

A newborn foal was presented because it was unresponsive and in cardiopulmonary arrest. Aggressive cardiopulmonary cerebral resuscitation was administered to the foal, which revived the foal; however, acute renal failure developed. Fluid retention and azotemia occurred although the foal was alert and able to suckle. A 6‐hour renal replacement therapy session using hemodiafiltration and a continuous renal replacement therapy machine was administered to the foal at 3 days of age which lowered the foal's azotemia and facilitated removal of some of the excess body fluid. Despite therapy, the foal developed pulmonary edema and was euthanized. Although the foal in this case did not survive, this report highlights the possibility of developing postresuscitation complications such as acute renal failure and describes the use of renal replacement therapy using hemodiafiltration as a viable option in neonatal foals with acute kidney injury.