Seroprevalence of a “new” bacterium, Simkania negevensis, in renal transplant recipients and in hemodialysis patients

Abstract

Background Simkania negevensis is an obligate intracellular bacterium belonging to the family Simkaniaceae in the Chlamydiales order. It is considered an ubiquitous microorganism and aquatic environments may be involved as a source of infection for humans. It was just isolated in samples from domestic water supplies and from mains water supplies, like spa water or swimming pool water, confirming its ability to resist to the common chlorination treatments. Evidence indicates a possible role of the microorganism in respiratory tract infections, in gastroenteric disorders and in the pathogenesis of cardiovascular disease, furthermore it has hypothesized that it could play a role in lung transplant rejection. Prevalence and possible effects in nephrology are unknown.MethodsWe examined the occurrence of Simkania negevensis in two differents populations, both characterized by a high susceptibility to infectious complications: 105 hemodialysis patients, 105 renal transplant recipients and 105 healthy subjects through the IgG and IgA response to Simkania negevensis in their sera. Serum antibodies to Simkania negevensis were detected by a homemade ELISA performed according to the Kahane’s protocol. Furthermore water samples from hemodialytic circuit were collected, to evaluate Simkania negevensis resistance to usual treatment of disinfection.ResultsOur results were unexpected, showing a higher seroprevalence of antibodies against Simkania negevensis in the hemodialysis patients, compared to renal transplant patients (IgG 22% vs 9% - IgA 9% vs 3%). S. negevensis was isolated in all water samples analyzed.ConclusionsOur study detected for the first time the occurrence of S. negevensis in hemodialysis and in renal transplant patients. Our findings suggest that water used in hemodialysis could be one of the possible sources of S. negevensis infection, without clinical involvement risk for patients.

Immunological Effects of a Single Hemodialysis Treatment

“…When comparing the patients grouped according to the type of vascular access, we found that the ones with arteriovenous graft and tunneled-cuffed-catheter displayed higher circulating levels of inflammation markers (CRP, IL-6, and TNF-α), increased expression on monocyte surface of cell activation markers (CD14, CD44, and CD32), and higher relative number of monocytes with a senescent phenotype (CD14+ CD32+) than those with a native fistula [46]. These results probably reflect the prolonged and continued use of central venous catheter or graft, which determines either the contact of the monocytes with an artificial material or monocyte activation after subclinical infection [47,48].…”

Serological Study of Infection with the Chlamydia - Like Microorganism 'Simkania Negevensis' in Patients Undergoing Hemodialysis

“…This is probably due to lack of proper periodic disinfection procedures in water treatment system. But in the study of Angletti et al (5) they collected the water samples; half of them from tap sited before specific treatment of disinfection and a half of them after specific treatment of disinfection. They found a higher seroprevalence of antibodies against Simkania negevensis in the hemodialysis patients, compared to renal transplant patients (IgG 22% vs 9% -IgA 9% vs 3%).…”

“…Angeletti et al (5) examined the occurrence of S. negevensis in two HD population, characterized by high susceptibility to infectious complications. They detected for the first time the occurrence of S. negevensis in hemodialysis and suggested that water used in hemodialysis could be one of the possible sources of S. negevensis infection, without clinical involvement risk for patients.…”

What is the true clinical relevance of Simkania negevensis and other emerging Chlamydiales members?

“…We observed the quasi-absence of human exposure to S. negevensis in pregnant women and young adults from Switzerland, pregnant women from England and an adult population from Israel, while previous studies had reported a seroprevalence of 46% among English pregnant women [19] and 55% to 80% among adults in Israel [7] . Both studies were performed using the same previously developed enzyme-linked immunosorbent assay (ELISA) [24] . This assay was also recently used in an Italian population and reported a similar high seroprevalence, ranging 9% to 30% [24] .…”

“…Both studies were performed using the same previously developed enzyme-linked immunosorbent assay (ELISA) [24] . This assay was also recently used in an Italian population and reported a similar high seroprevalence, ranging 9% to 30% [24] .…”