Prevalence of Simkania negevensis in chlorinated water from spa swimming pools and domestic supplies.

AIMS: This study aimed to investigate the prevalence of Simkania negevensis in the chlorinated water of spa swimming pools and domestic network systems. METHODS AND RESULTS: A total of 10 and 36 samples were collected from two domestic water supplies and four spa facilities, respectively. Simkania negevensis was isolated in Acanthamoeba castellanii monolayers and detected by Gimenez staining and immunofluorescence test. Simkania negevensis DNA, extracted from the positive samples, was confirmed by a nested PCR assay followed by sequencing. Simkania negevensis was detected in 41·3% of samples (domestic water: 50%; untreated spa supply water: 25%; chlorinated spa pool water: 42·9%) from all the examined water systems in successive samplings performed in 1 year. The presence of S. negevensis was not correlated with the counts of Heterotrophic Bacteria and Pseudomonas aeruginosa. Unlike Legionella spp., which were never isolated from the swimming-pool water samples, S. negevensis was also detected in chlorinated spa water. CONCLUSIONS: This investigation shows that Simkania is widespread in natural and man-made aquatic environments, which may represent possible sources of infection: in the swimming pools, in particular, the aerosol generated by the water movement could increase the risk of inhalation of infected particles. SIGNIFICANCE AND IMPACT OF THE STUDY: This study represents the first evidence of the presence of S. negevensis in spa pool water. Sero-epidemiological surveys on spa users could help to clarify its transmission in this environment.

Hypoxia induces cell damage via oxidative stress in retinal epithelial cells.

Retinal diseases (RD), including diabetic retinopathy, are among the most important eye diseases in industrialized countries. RD is characterized by abnormal angiogenesis associated with an increase in cell proliferation and apoptosis. Hypoxia could be one of the triggers of the pathogenic mechanism of this disease. A key regulatory component of the cell's hypoxia response system is hypoxia-inducible factor 1 alpha (HIF-1α). It has been demonstrated that the induction of HIF-1α expression can be also achieved in vitro by exposure with cobalt chloride (CoCl2), leading to an intracellular hypoxia-like state. In this study we have investigated the effects of CoCl2 on human retinal epithelium cells (hRPE), which are an integral part of the blood-retinal barrier, with the aim to determine the possible role of oxidative stress in chemical hypoxia-induced damage in retinal epithelial cells. Our data showed that CoCl2 treatment is able to induce HIF-1α expression, that parallels with the formation of reactive oxygen species (ROS) and the increase of lipid 8-isoprostanes and 4-hydroxynonenal (4-HNE) protein adducts levels. In addition we observed the activation of the redox-sensitive transcription factor nuclear factor-kappaB (NFkB) by CoCl2 which can explain the increased levels of vascular endothelial growth factor (VEGF). The increased number of dead cells seems to be related to an apoptotic process. Taken together these evidences suggest that oxidative stress induced by hypoxia might be involved in RD development through the stimulation of two key-events of RD such as neo-angiogenesis and apoptosis.