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Annals of the New York Academy of... Aug 2011We know surprisingly little about the evolutionary origins of Chlamydia trachomatis. It causes both ocular (trachoma) and sexually transmitted infections in humans, it... (Review)
Review
We know surprisingly little about the evolutionary origins of Chlamydia trachomatis. It causes both ocular (trachoma) and sexually transmitted infections in humans, it is an obligate intracellular pathogen, and there are only a few "isolates" that have been well characterized. From the first few genomes analyzed, it seems that the C. trachomatis genome is highly conserved. The genomes possess high synteny and, in some cases, the sequence variation between genomes is as little as 20 SNPs. Recent indications from partial genome analyses suggest that recombination is the mechanism for generating diversity. There is no accurate molecular clock by which to measure the evolution of C. trachomatis. The origins of both sexually transmitted and ocular C. trachomatis are unclear, but it seems likely that they evolved with humans and shared a common ancestor with environmental chlamydiae some 700 million years ago. Subsequently, evolution within mammalian cells has been accompanied by radical reduction in the C. trachomatis genome.
Topics: Animals; Bacteriophages; Chlamydia Infections; Chlamydia trachomatis; Drug Resistance, Bacterial; Evolution, Molecular; Genome, Bacterial; Humans; Plasmids
PubMed: 22239534
DOI: 10.1111/j.1749-6632.2011.06194.x -
Best Practice & Research. Clinical... Dec 2002Chlamydiae are obligate intracellular bacteria, parasitizing eukaryotic cells. Chlamydia trachomatis, C. psittaci and C. pneumoniae are the three species of chlamydiae... (Review)
Review
Chlamydiae are obligate intracellular bacteria, parasitizing eukaryotic cells. Chlamydia trachomatis, C. psittaci and C. pneumoniae are the three species of chlamydiae pathogenic to humans. C. trachomatis shows a tropism for the genital and conjunctival epithelia and consists of 19 different serovars which are pathogenic predominantly for the urogenital tract.A distinguishing feature of chlamydiae is their transition between the infectious elementary body that enters the host cell and the non-infectious reticulate body that replicates intracellularly within an inclusion that does not fuse with lysosomes. Chlamydiae depend for some functions upon the host cell; in particular, chlamydiae have little capacity for generating energy. The complete sequence of the 1000-kb chromosome of C. trachomatis is known, as are most of the genes located on the 7.5-kb cryptic plasmid. Recently, several concepts about the biology and the metabolic pathways of C. trachomatis have been revised in relation to the genome sequence, and different novel proteins have been described.
Topics: Chlamydia Infections; Chlamydia trachomatis; Genome, Bacterial; Humans
PubMed: 12473280
DOI: 10.1053/beog.2002.0323 -
Future Microbiology Apr 2010Chlamydial infections are highly newsworthy, but basic research into Chlamydia trachomatis is severely hampered by a series of formidable technical barriers. This has... (Review)
Review
Chlamydial infections are highly newsworthy, but basic research into Chlamydia trachomatis is severely hampered by a series of formidable technical barriers. This has resulted in a paucity of information with respect to the genetics and population structure of these recalcitrant bacteria. Here we present a review of what is currently known about the genomics of C. trachomatis and discuss the usefulness of molecular typing systems and the prospects of developing a pan-chlamydial genome resource.
Topics: Bacterial Typing Techniques; Chlamydia Infections; Chlamydia trachomatis; DNA Fingerprinting; Genome, Bacterial; Genotype; Humans
PubMed: 20353297
DOI: 10.2217/fmb.10.31 -
Microbiological Research 2006Chlamydial persistence is a reversible state generated during conditions deleterious to growth. In persistence, Chlamydia trachomatis remains viable but atypical, with... (Review)
Review
Chlamydial persistence is a reversible state generated during conditions deleterious to growth. In persistence, Chlamydia trachomatis remains viable but atypical, with an enlarged, aberrant form and quiescent metabolism. It favours chronic chlamydiosis, leading to serious sequelae. Although the mechanism of persistence formation is still unknown, more reliable molecular approaches tend to confirm that its occurs in vivo, even lasting 3 years. One approach consists of identifying unprocessed rRNA found only in viable Chlamydia, when infection is not apparent. Another approach, referring to the fact that immunity is type-specific, consists of showing by genotyping that multiple recurrences are due to the same genovar. At the molecular level, persistence is characterized by increased expression of ct755, one of the three heat shock protein (hsp60)-coding genes. In addition, chromosomal replication occurs continuously, and cell division is blocked possibly due to the repression of genes such as ftsW and amiA. At the immunological level, persistence reveals the failure of host-defence mechanisms because of reduced or suppressed pro-inflammatory or cytotoxic responses.
Topics: Anti-Bacterial Agents; Chlamydia Infections; Chlamydia trachomatis; Female; Humans; Treatment Failure
PubMed: 16338585
DOI: 10.1016/j.micres.2005.04.004 -
Current Topics in Microbiology and... 2018The lifestyle of Chlamydiae is unique: the bacteria alternate between two morphologically distinct forms, an infectious non-replicative elementary body (EB), and a... (Review)
Review
The lifestyle of Chlamydiae is unique: the bacteria alternate between two morphologically distinct forms, an infectious non-replicative elementary body (EB), and a replicative, non-infectious reticulate body (RB). This review focuses on recent advances in understanding the structure and function of the infectious form of the best-studied member of the phylum, the human pathogen Chlamydia trachomatis. Once considered as an inert particle of little functional capacity, the EB is now perceived as a sophisticated entity that encounters at least three different environments during each infectious cycle. We review current knowledge on its composition and morphology, and emerging metabolic activities. These features confer resistance to the extracellular environment, the ability to penetrate a host cell and ultimately enable the EB to establish a niche enabling bacterial survival and growth. The bacterial and host molecules involved in these processes are beginning to emerge.
Topics: Chlamydia trachomatis; Humans
PubMed: 27197644
DOI: 10.1007/82_2016_12 -
Emerging Infectious Diseases Apr 2018We report an HIV-infected person who was treated for lymphogranuloma venereum cervical lymphadenopathy and proctitis in Croatia in 2014. Infection with a variant L2b... (Review)
Review
We report an HIV-infected person who was treated for lymphogranuloma venereum cervical lymphadenopathy and proctitis in Croatia in 2014. Infection with a variant L2b genovar of Chlamydia trachomatis was detected in a cervical lymph node aspirate. A prolonged course of doxycycline was required to cure the infection.
Topics: Humans; Male; Chlamydia trachomatis; Coinfection; Croatia; HIV Infections; Lymph Nodes; Lymphogranuloma Venereum; Proctitis
PubMed: 29553338
DOI: 10.3201/eid2404.171872 -
Pathogens and Disease Jan 2022Mycoplasma contamination of cell culture represents a serious problem in research and decontamination from cell-propagated obligate intracellular bacteria has proven...
Mycoplasma contamination of cell culture represents a serious problem in research and decontamination from cell-propagated obligate intracellular bacteria has proven challenging. Here, we presented an optimized protocol to remove Mycoplasma from contaminated Chlamydia trachomatis culture. A stepwise procedure of Mycoplasma removal entails (i) incubation in nonionic detergent-containing solution and (ii) separation of viable chlamydial organisms by fluorescence-activated cell sorting (FACS), followed by subcloning using a focus-forming assay. We also adapted a polymerase chain reaction (PCR) assay using paired universal and Mycoplasma-specific primers, which are distinguishable from the C. trachomatis counterparts, in combination with Sanger sequencing to determine the presence of mycoplasmas' 16S rRNA genes. These integrated approaches allow for full removal of Mycoplasma, as verified by the improved PCR assay, without compromising the capacity of viable C. trachomatis to adapt to new infection in epithelial cells. Some pitfalls during the Mycoplasma decontamination process are discussed.
Topics: Cell Culture Techniques; Cells, Cultured; Chlamydia trachomatis; Decontamination; Humans; Mycoplasma
PubMed: 34918079
DOI: 10.1093/femspd/ftab056 -
Archivum Immunologiae Et Therapiae... 2003Chlamydia trachomatis (C. trachomatis) is one of the most common sexually transmitted bacterial agents. What distinguishes it from other organisms is its intracellular... (Review)
Review
Chlamydia trachomatis (C. trachomatis) is one of the most common sexually transmitted bacterial agents. What distinguishes it from other organisms is its intracellular reproductive cycle. Up to now, four antigens have been identified in the Chlamydia genus: genus-specific antigen as well as species-specific, type-specific and subspecies-specific. C. trachomatis is a powerful immunogen which stimulates the host's immunological processes. The intracellular parasitism of the bacteria is the basis for both symptomatic or asymptomatic infection as well as for chronic ones. The primary infection leads to a local inflammatory reaction due to penetration and reproduction of the bacteria in the epithelial cells and to IgA secretory antibody production. In most cases the host's reaction to the primary infection is transient and does not cause tissue damage. In the course of chronic infection or reinfection, the most important processes are those of delayed hypersensitivity, which lead to a fast and intense immunological reaction of specifically sensitized Th1 lymphocytes. This reaction leads to progressive damage of the epithelial cells and to cicatrization and fibrosis, which means irreversible complications. Interferon gamma is of special importance in the process of C. trachomatis infection. High concentrations of it inhibit the bacteria's reproductive cycle, while lower concentrations promote the development of atypical, non-contagious forms of Chlamydia of diminished metabolic activity and altered antigenicity. The chlamydial heat shock proteins are considered to be of great importance lately. Their molecular weights of 60 and 10 kDa are a powerful stimulant of immunological reactions and show significant homology (40-90%) to human and other bacterial heat shock proteins.
Topics: Animals; Chlamydia Infections; Chlamydia trachomatis; Chronic Disease; Humans; Recurrence
PubMed: 14626428
DOI: No ID Found -
European Journal of Epidemiology Dec 1985Chlamydia trachomatis is an obligate intracellular energy parasitic bacterium with a genome of 660 X 10(6) daltons, possessing a plasmid and unique life cycle which... (Review)
Review
Chlamydia trachomatis is an obligate intracellular energy parasitic bacterium with a genome of 660 X 10(6) daltons, possessing a plasmid and unique life cycle which includes the differentiation of the infective elementary body to a replicative reticulate body. C. trachomatis is the etiological agent of trachoma, which affects approximately 500 million people in developing countries. Recently it became evident that in industrialised Western nations certain strains of C. trachomatis are the most common cause of sexually transmitted infections such as non-gonococcal urethritis, cervicitis, endometritis, salpingitis and subsequent ectopic pregnancies or infertility, perihepatitis, neonatal conjunctivitis and pneumonia, adult conjunctivitis and epididymitis. Since C. trachomatis infections are often asymptomatic, widespread screening of sexually active young people is needed in order to initiate early antibiotic treatment which may prevent serious complications such as ectopic pregnancies and infertility. Development of sensitive and simple techniques for mass screening for detection of Chlamydia in excretions as well as techniques for detection of specific markers of chronic internal infections (such as Chlamydia specific IgA antibodies) is of great importance.
Topics: Chlamydia Infections; Chlamydia trachomatis; Female; Genital Diseases, Female; Genital Diseases, Male; Humans; Male; Mass Screening; Respiratory Tract Infections
PubMed: 3915982
DOI: 10.1007/BF00237099 -
Infection, Genetics and Evolution :... Jun 2013The obligate intracellular pathogen Chlamydia trachomatis is the causative agent of the blinding trachoma and the world's leading cause of bacterial sexually transmitted... (Review)
Review
The obligate intracellular pathogen Chlamydia trachomatis is the causative agent of the blinding trachoma and the world's leading cause of bacterial sexually transmitted infections. Despite aggressive antibacterial control measures, C. trachomatis infections have been increasing, constituting a serious public health concern due to its morbidity and socioeconomic burden. Still, very little is known about the molecular basis underlying the phenotypic disparities observed among C. trachomatis serovars in terms of tissue tropism (ocular conjunctiva, epithelial-genitalia and lymph nodes), virulence (disease outcomes) and ecological success. This is in part due to the inexistence of straightforward tools to genetically manipulate Chlamydiae and host cell-free growth systems, hampering the elucidation of the biological role of loci. The recent release of tenths of full-genome C. trachomatis sequences depict a strains clustering scenario reflecting the organ/cell-type that they preferentially infect. However, the high degree of genomic conservation implies that few genetic features are involved in phenotypic dissimilarities. The purpose of this review is to gather the most relevant data dispersed throughout the literature concerning the genotypic evidences that support niche-specific phenotypes. This review focus on chromosomal dynamics phenomena like recombination and point-mutations, essentially involving outer and inclusion membrane proteins, type III secretion effectors, and hypothetical proteins with unknown function. The scrutiny of C. trachomatis loci involved in tissue tropism, pathogenesis and ecological success is crucial for the development of disease-specific prophylaxis.
Topics: Animals; Chlamydia Infections; Chlamydia trachomatis; Genome, Bacterial; Humans; Phenotype; Point Mutation; Recombination, Genetic
PubMed: 23523596
DOI: 10.1016/j.meegid.2013.03.018