Chlamydophila felis
| Chlamydophila felis | ||||||||||||
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| Scientific name | ||||||||||||
| Chlamydophila felis | ||||||||||||
| Everett et al., 1999 |
Chlamydophila felis is a bacterium from the group of chlamydia and the bacterial causative agent of cat flu , more precisely of feline chlamydiosis . It was previously regarded as a variant of the species Chlamydia psittaci and was established as a separate species in 1999. The genome of the strain Chlamydophila felis Fe / C-56 was completely sequenced in 2006.
features
Chlamydophila felis shows the typical characteristics of the group of chlamydia, so it can only occur intracellularly, i.e. H. multiply within the cells of a host . Like other chlamydia, it exists in the form of metabolically inactive elementary bodies (EK), which are important for the pathway of infection and live in the host cells as reticular bodies (reticular bodies, abbreviation RK). It is called a gram-negative bacterium because it - as elementary body - is colored red in the gram stain by the dyes used. This is usually caused by a thin layer of murein (consisting of peptidoglycans) in the cell wall , in contrast to the gram-positive bacteria, which have a thick layer of murein. Genetic studies have shown that the members of the Chlamydiaceae family have genes that are required for the synthesis of peptidoglycans. However, the studies show that their cell walls contain only very small amounts or no peptidoglycan at all.
Because of the parasitic metabolism, C. felis cannot be cultivated on the nutrient media commonly used in microbiology ; cell cultures are required instead . HeLa cells (human epithelial cells ) are usually used for this. To distinguish between Chlamydia species, it is important to know that C. felis can not produce glycogen as a storage substance.
genetics
The genome of the strain Chlamydophila felis Fe / C-56 was completely sequenced in 2006 . This bacterial strain was isolated from a domestic cat suffering from conjunctivitis (conjunctivitis) . The genome has a size of 1174 kilobase pairs (kb), which is only 25% of the genome size of Escherichia coli . There are 1013 proteins annotated . The small size of the genome is an indication of the parasitic way of life. Over time, the bacterium has lost the ability to synthesize numerous metabolites as it receives these from the host cells.
The result of the sequencing shows a GC content (the proportion of the nucleobases guanine and cytosine ) in the bacterial DNA of around 39 mol percent. In addition to the bacterial chromosome , this C. felis strain also has a plasmid with a genome size of 7.5 kb.
Pathogenicity
C. felis is assigned to risk group 2 by the Biological Agents Ordinance in conjunction with TRBA 466 and identified as a zoonotic agent . This basically points out the possibility that an infection can be transmitted directly or indirectly between animals and humans. In fact, there are some documented cases of C. felis being transmitted from cats to humans.
proof
C. felis has - deposited on its cell wall - lipopolysaccharides . These compounds of fat-like components, combined with three sugar components , act as antigen and can be used serologically for the detection. In clinical diagnostics, however, detection is more common by means of an increased titer of antibodies , but the antigens used usually also indicate other Chlamydophila or Chlamydia species.
The detection of certain parts of the bacterial genome using the PCR method ( polymerase chain reaction ) is much more specific . Gene segments that are typical for the type of bacteria are copied and detected. A process developed in 2010 is based on Real Time Quantitative PCR ( q-PCR ), using the fluorescent dye SYBR Green, which attaches to the gene segments and causes fluorescence. The strength of the fluorescence is recorded in real time during a PCR cycle (hence the term real time ) and is used for the quantitative determination of the gene segments present and thus a quantitative determination of the bacterial species. The method developed in Japan aims to detect Chlamydophila psittaci , but other Chlamydophila species that are pathogenic to animals can also be detected. a. C. felis to prove it. Clinical samples (e.g. faeces ) or infected cells can be used, from which the DNA is first extracted and then used for the q-PCR .
Occurrence
The natural habitat of C. felis is the house cat, the pathogen can be detected worldwide.
Systematics
External system
The systematics of the order Chlamydiales - and thus also of the genera Chlamydia and Chlamydophila - has evolved through the studies of Everett et al. a. from 1999 fundamentally changed. Previously, Chlamydophila felis was assigned to the species Chlamydia psittaci (now referred to as Chlamydophila psittaci ), with the peculiarity that this bacterium was not found in birds, as is usual, but in cats. As a result of the investigations, C. felis was classified as a separate species .
Internal system
The species Chlamydophila felis can be divided into several serotypes . Up to now it has been common practice to differentiate between different bacterial strains. Everett et al. a. show that the "FP Pring" and "FP Cello" strains have a plasmid, but the "FP Baker" strain does not. This strain is considered the type strain for the species, it is also listed under the designation ATCC VR-120. This strain is used as a live attenuated vaccine to vaccinate cats.
etymology
The species name refers to the occurrence, felis from Latin means "the cat" ( genitive ), thus refers to the house cat as the most important host.
(Veterinary) medical importance
C. felis is endemic in front in domestic cats and is with them a pathogen of conjunctivitis (pink eye) and rhinitis (runny nose), more rarely, pneumonitis, especially in the context of cat flu .
The transferability to humans is possible, although so far only individual cases have been scientifically documented. Chlamydia trachomatis is often the causative agent of conjunctivitis in human patients . In a case study, a more detailed examination of a patient with chronic conjunctivitis ruled out an infection with C. trachomatis . This was followed by isolating the pathogen and then isolating a bacterium from the patient's cat. Both samples were found to be Chlamydophila felis , so zoonosis is likely. The infection was successfully treated with the antibiotic doxycycline . In general, antibiotics from the group of tetracyclines and macrolides are used to treat infections with C. felis and related species . Penicillin and other antibiotics with the same mode of action ( beta-lactam antibiotics ) are ineffective because their site of action, the peptidoglycan, is not present in Chlamydophila .
Individual evidence
- ↑ a b Michael T. Madigan, John M. Martinko, Jack Parker: Brock Mikrobiologie. German translation edited by Werner Goebel, 1st edition. Spectrum Akademischer Verlag GmbH, Heidelberg / Berlin 2000, ISBN 978-3-8274-0566-1 , pp. 588-591.
- ↑ a b c d e f g h K. D. Everett, RM Bush, AA Andersen: Emended description of the order Chlamydiales, proposal of Parachlamydiaceae fam. nov. and Simkaniaceae fam. nov., each containing one monotypic genus, revised taxonomy of the family Chlamydiaceae, including a new genus and five new species, and standards for the identification of organisms. In: International journal of systematic bacteriology. Volume 49 Pt 2, April 1999, pp. 415-440, ISSN 0020-7713 . PMID 10319462 .
- ^ A b c Herbert Hof, Rüdiger Dörries: Dual series: Medical microbiology . 3. Edition. Thieme Verlag, Stuttgart 2005, ISBN 978-3-13-125313-2 , p. 447-451 .
- ↑ a b H. Okuda, K. Ohya et al. a .: Detection of Chlamydophila psittaci by using SYBR green real-time PCR. In: The Journal of veterinary medical science / the Japanese Society of Veterinary Science. Volume 73, Number 2, February 2011, pp. 249-254, ISSN 0916-7250 . PMID 20948172 .
- ↑ a b Chlamydophila felis Fe / C-56. In: Website Genomes Online Database (GOLD) . Retrieved October 24, 2013 .
- ↑ a b c Chlamydophila felis. In: National Center for Biotechnology Information (NCBI) Genome website . Retrieved October 24, 2013 .
- ↑ TRBA (Technical Rules for Biological Agents) 466: Classification of prokaryotes (Bacteria and Archaea) into risk groups. In: Website of the Federal Institute for Occupational Safety and Health (BAuA). April 25, 2012, accessed March 9, 2013 .
- ^ J. Schachter, HB Ostler, KF Meyer: Human infection with the agent of feline pneumonitis. In: The Lancet . Volume 1, Number 7605, May 1969, pp. 1063-1065, ISSN 0140-6736 . PMID 4181729 .
- ^ Jean Euzéby, Aidan C. Parte: Genus Chlamydophila. (No longer available online.) In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Archived from the original on October 29, 2013 ; Retrieved October 24, 2013 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ JC Hartley, S. Stevenson et al. a .: Conjunctivitis due to Chlamydophila felis (Chlamydia psittaci feline pneumonitis agent) acquired from a cat: case report with molecular characterization of isolates from the patient and cat. In: Journal of Infection . Volume 43, Number 1, July 2001, pp. 7-11, ISSN 0163-4453 . doi : 10.1053 / jinf.2001.0845 . PMID 11597148 .
