Seroprevalence of IgG antibodies to the chlamydia-like microorganism ‘Simkania Z’ by ELISA

Abstract

The newly described microorganism 'Simkania Z', related to the Chlamydiae, has been shown to be associated with bronchiolitis in infants and community acquired pneumonia in adults. The prevalence of infection in the general population is unknown. A simple ELISA assay for the detection of serum IgG antibodies to 'Simkania Z' was used to determine the prevalence of such antibodies in several population samples in southern Israel (the Negev). The groups tested included 94 medical and nursing students, 100 unselected blood donors, 106 adult members of a Negev kibbutz (communal agricultural settlement), and 45 adult Bedouin, residents of the Negev. IgG antibodies to 'Simkania Z' were found in 55-80% of these presumably healthy individuals, independently of antibodies to Chlamydia trachomatis and Chlamydia pneumoniae. The Bedouin had a seropositivity rate of 80%, while all other groups had rates of between 55 and 64%. These results indicate that 'Simkania Z' infection is probably common in southern Israel.

Simkania negevensis, an insight into the biology and clinical importance of a novel member of the Chlamydiales order

“…Caution should be taken when interpreting these results. The seroprevalence appears high in the Middle East (Israel and Jordanian), ranging from 55 to 65% among healthy adults and reaching 80% in Bedouins (Al-Younes & Paldanius, 2014;Friedman et al, 1999). Serological evidence of past infection was documented in 46% of pregnant women in Cornwall, UK (Friedman et al, 2006) and in 41% of Danish blood donors (Johnsen et al, 2005).…”

The growth cycle of Simkania negevensis

“…Exposure to the organism is widespread in the Negev region of Israel (Friedman et al, 1999), in Vancouver, BC, Canada, in Brooklyn, NY, and in Lima, Peru (unpublished data). Members of two other families in the Chlamydiales, the well-studied Chlamydiaceae and the family of Parachlamydiaceae, have also been associated with respiratory disease (Schachter, 1999 ;Birtles et al, 1997).…”

“…It has been proposed that Simkania negevensis be assigned to the new family Simkaniaceae, in the order Chlamydiales, based on its intracellular bimorphic parasitic growth in cultured cells and on rDNA sequence comparisons (Kahane et al, 1999 ;Everett et al, 1999). Its genome length is 1n7 Mbp, compared to 1n0-1n2 Mbp for members of the family Chlamydiaceae (Kahane et al, 1999) ; its full-length 16S and 23S rDNA sequences are each 80-87 % identical to those of members of the Chlamydiaceae, whereas all members of the Chlamydiaceae have 90 % identity with each other.…”

Simkania negevensis: Is it a real respiratory pathogen?

“…The seropositivity of S. negevensis in the healthy population in Israel, the United Kingdom and Denmark has been determined to be %46-80 [6][7][8].…”

“…Simkania negevensis has been reported to be frequently seen in Israel, North America and Western Europe, whereas no regional limitation has been made [3,[6][7][8]. For instance, in a study by Yamaguchi et al [13] conducted in Japan in a group of 588 healthy people, S. negevensis specifi c IgG was searched for with the MIF technique and a positivity rate of 4.3% was found in healthy volunteers.…”