High rate of Simkania negevensis among Canadian Inuit infants hospitalized with lower respiratory tract infections
ABSTRACT To determine the prevalence of Simkania negevensis in causing pulmonary infections in children, nasopharyngeal washes were obtained from 22 infants hospitalized with acute bronchiolitis in the Baffin Island, Canada. 14 (63.6%) were positive for S. negevensis. Mixed infections with other respiratory viruses were common. All patients recovered without specific antibiotic treatment. Even though a high prevalence of S. negevensis was found, this organism may potentially well be an opportunistic agent rather than a true pathogen.
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ABSTRACT: Accumulating evidence supports a role for Chlamydia-related organisms as emerging pathogens for human and animals. Assessment of their pathogenicity requires strain availability, at least for animal models and serological studies. As these obligate intracellular species are able to grow inside amoebae, we used co-culture with Acanthamoeba castellanii in an attempt to recover new Chlamydia-related species from river water. We isolated two strains from eight water samples. The first strain is a new Parachlamydia acanthamoebae strain that differs from previously described isolates by only two bases in the complete 16S rRNA gene sequence. The second isolate is the first representative of a new Chlamydiales family, as demonstrated by genetic and phylogenetic analyses of the 16S rRNA, 23S rRNA, ADP/ATP translocase and RnpB encoding genes. Using fluorescent in situ hybridization and electron microscopy, we demonstrated that it grows in high numbers in amoebae, where it exhibits a Chlamydia-like developmental cycle with reticulate bodies and star-like elementary bodies. Based on these results, we propose to name this new species 'Criblamydia sequanensis'. This work confirmed that amoebal co-culture is a relevant method to isolate new chlamydiae, and that it can be successfully applied to ecosystems colonized with a complex microbial community.Environmental Microbiology 01/2007; 8(12):2125-35. DOI:10.1111/j.1462-2920.2006.01094.x · 6.24 Impact Factor
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ABSTRACT: The bacterium Simkania negevensis is a germ associated with respiratory diseases. This study aims at estimating the prevalence of Simkania in the Jordanian population. Serum samples from 664 Jordanian males and females, aged 2 to 86 years were collected. IgG and IgM Simkania-specific antibodies were detected using an indirect immunofluorescence test. Seropositivity titers for IgG and IgM were defined as 1:8 and 1:10, respectively. The overall prevalence of IgG antibody in all examined Jordanian nationals was 58.4%. IgG seropositivity was low in children under the age of 10 years (34.2%), and increased rapidly with age and ranged between 49.4% and 72%. Simkania-specific IgM was detected in 24.8% of subjects. IgM prevalence in children under 10 years was lowest (10.5%) and increased in older ages and remained above 20%. Overall detection rates of both IgG and IgM were significantly higher in females than males (60.7% vs. 54.5% for IgG and 26.7% vs. 21.7% for IgM). These data indicate that Simkania infection is highly prevalent in Jordan. The high level of seropositivity is most likely maintained by re-infections or chronic infections. Our data may serve as a basis to elucidate the pathogenesis of Simkania in Jordan.Brazilian Journal of Microbiology 01/2014; 45(4):1433-1437. DOI:10.1590/S1517-83822014000400038 · 0.45 Impact Factor
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ABSTRACT: Cell division in bacteria takes place at the midcell and occurs after DNA has been duplicated and segregated into two nucleoids. The division process starts with the localization of FtsZ at the center of the cell and formation of a septal ring structure called Z-ring. Once the septum is fully formed, the Z-ring disappears and the daughter cells separate. An ordered assembly of other proteins follows this process (eg. FtsA, ZipA, FtsK, FtsQ, FtsL, FtsB, FtsW, FtsI, FtsN). FtsZ is a highly conserved protein that is found in most of the major groups of bacteria. FtsZ is a structural homolog of tubulin; like tubulin, purified FtsZ binds and hydrolyses GTP and assembles in vitro into filaments, sheets and other structures. One important inhibitory system, the Min system, is crucial for the precise positioning of the Z-ring. In E. coli this system consist of the FtsZ assembly inhibitor, MinC protein, and the MinD and MinE proteins which move from one cell pole to the other. Because MinC is associated with the relocating MinD protein, FtsZ assembly is inhibited at the cell poles. Another important regula- tory system is nucleoid occlusion. Like Min system, nucleoid occlusion negatively regulates Z-ring assembly. Acting independently of the Min system nucleoid occlusion prevents the assembly of the Z ring on top of unreplicated chromosomal DNA. Several positive and negative regulators of Z ring assembly are known eg. ZipA, EzrA, ClpX, SulA, Noc proteins. The lack of FtsA, ZipA and FtsN cell division proteins suggests that the mechanisms of cell division are likely to be different in Mycobacterium as compared with E. coli. FtsZ and FtsQ are essential cell division proteins in Mycobacterium smegmatis and M. tuberculosis. The C-termini of M. tuberculosis FtsZ and FtsW carries a string of amino acid residues that are absent in their E. coli counterparts. FtsZ and FtsW of M. tuberculosis are binding partners and that binding involves a cluster of aspartate residues in the C-tail of FtsZ.