Chlamydophila psittaci

Chlamydophila psittaci
Chlamydophila psittaci (staining by direct immunofluorescence with fluorescent antibodies (FA))
Systematics
Domain : Bacteria (bacteria) Department : Chlamydiae Order : Chlamydiales Family : Chlamydiaceae Genre : Chlamydophila Type : Chlamydophila psittaci
Scientific name
Chlamydophila psittaci
( Lillie , 1930) Everett et al., 1999

Chlamydophila psittaci , taxonomically correct today as Chlamydia psittaci , is a gram-negative bacterium from the group of chlamydia and the causative agent of ornithosis (parrotdisease) in birds and humans. The genome of nine strains of Chlamydophila psittaci was completely sequenced in 2012.

features

Chlamydophila psittaci shows the typical characteristics of the group of chlamydia. Like all chlamydia, C. psittaci can only spread intracellularly, i. H. multiply within the cells of a host because the bacteria cannot synthesize nucleotides . The other biological properties also largely correspond to those of other chlamydia (see there). A special feature is that C. psittaci in the form of small persistent forms, so-called elementary bodies, can remain infectious outside of a host organism for weeks.

genetics

The genome of the strain Chlamydophila psittaci 6BC was completely sequenced in 2011 . The genome has a size of 1179 kilobase pairs (kb), which is only 25% of the genome size of Escherichia coli . 975 proteins are 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. Besides the bacterial chromosome , this strain of C. psittaci also has a plasmid with a genome size of 7.5 kb.

In 2012, a genetic examination of all nine known strains (nine different genotypes ) of C. psittaci followed . The size of the genome varies between 1141 and 1172 kb, with the exception of one bacterial strain, all of them also have an extrachromosomal plasmid. The GC content in the bacterial DNA is between 38.7 and 39.1 mol percent.

Pathogenicity

C. psittaci is  assigned to risk group 3 by the Biological Agents Ordinance in conjunction with TRBA 466 and identified as a zoonotic agent . A transmission of C. psittaci from animals to humans is easily possible.

proof

The detection of certain parts of the bacterial genome can be done with the help of the PCR method ( polymerase chain reaction ). A method developed in 2010 is based on Real Time Quantitative PCR ( q-PCR ) and enables the quantitative determination of C. psittaci and other animal pathogenic Chlamydophila species, such as C. felis .

Occurrence

The natural reservoir of C. psittaci are birds, especially parrots (see name ). In these cases, the infection can lead to serious illnesses with fatal consequences, or cause only minor symptoms or remain inapparent. The C. psittaci genotypes known in 2012 were isolated from the following birds: cockatoos , budgerigars , lories and other parrots, pigeons , ducks , geese , turkeys and ratites . Some strains have also been found in humans , domestic cattle, and muskrats .

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 psittaci was called Chlamydia psittaci and together with Chlamydia trachomatis formed the genus Chlamydia . However, the genetic investigations showed clear differences between the two species, so that a new genus Chlamydophila was established with C. psittaci as the type species . Through publication in the International Journal of Systematic and Evolutionary Microbiology (IJSEM), a new taxon , such as genus or species, is validated, i.e. validly defined. Although this happened for Chlamydophila psittaci in 1999, the outdated term can still be found in some specialist literature. In 2009, some scientists suggested that the former generic name Chlamydia should be used again for all species. Until now (as of 2014), Chlamydophila psittaci is still the valid taxon according to the International Code of Nomenclature for Bacteria . However, a working group was set up by the International Commission for the Systematics of Prokaryotes to deal with the controversial term.

Internal system

The species Chlamydophila psittaci can be divided into several bacterial strains . To elucidate the tribal history - and the relationship between the organisms - one examines the DNA sequences and, in the case of bacteria, the 16S rRNA, a typical representative of ribosomal RNA for prokaryotes . In the Everett et al. a. from 1999 eight strains were distinguished and referred to as eight serovars . The results show that the genes of the 16S rRNA in these strains differ by less than 0.6%. The strain 6BC is considered to be the type strain for the species, it is also listed under the designation ATCC VR-125. The genetic studies of Van Lent et al. a. from 2012, nine bacterial strains were used, which are regarded as representatives of nine genotypes . These correspond to the serovars, except that with genotype E / B another has been added. The names of the strains are different, however, as some of them are not yet included in the major collections of microorganisms (such as the ATCC). This means that the results cannot simply be compared with one another. All strains examined are to be regarded as pathogenic (for the host animals) and as pathogens can be easily transmitted to humans.

etymology

The species name refers to the occurrence, psittaci from Latin means "of the parrot" ( genitive ), thus refers to the parrots (Psittaciformes) as the most important host.

Clinical significance

In Germany, an estimated 200 people develop ornithosis every year . As a rule, they are owners or breeders of ornamental birds. Ornithosis (or psittacosis) is recognized as an occupational disease for these and for those employed in poultry operations .

Symptoms

Typical manifestations of an infection with Chlamydophila psittaci are sudden onset with fever, headache as the main symptom, muscle pain, unproductive dry cough and dyspnoea.

treatment

Antibiotic therapy for a disease caused by Chlamydophila psittaci is done with doxycycline (alternatively clarithromycin ) or azithromycin for 10 to 21 days.

Reporting requirement

In Germany, the direct or indirect proof of by name is notifiable according to § 7 of the Infection Protection Act , as far as the proof indicates an acute infection.

swell

literature

• Helmut Hahn, Dietrich Falke, Stefan HE Kaufmann, Uwe Ullmann (eds.): Medical microbiology and infectious diseases . 5th edition. Springer-Verlag, Heidelberg 2004, ISBN 3-540-21971-4 .

Individual evidence

1. ↑ Species: Chlamydia psittaci. In: List of Prokaryotic names with Standing in Nomenclature (LPSN). Retrieved on May 29, 2020 (English). 
2. ↑ ^{a b} Chlamydophila psittaci 6BC. In: Website Genomes Online Database (GOLD) . Retrieved October 25, 2013 . 
3. ↑ ^{a b} Chlamydophila psittaci. In: National Center for Biotechnology Information (NCBI) Genome website . Retrieved October 25, 2013 . 
4. ↑ ^{a b c d} S. Van Lent, JR Piet u. a .: Full genome sequences of all nine Chlamydia psittaci genotype reference strains. In: Journal of bacteriology. Volume 194, Number 24, December 2012, pp. 6930-6931, ISSN  1098-5530 . doi : 10.1128 / JB.01828-12 . PMID 23209198 . PMC 3510619 (free full text).
5. ↑ 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, p. 54 , accessed March 9, 2013 . 
6. ↑ ^{a b c d} 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 .
7. ↑ 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 .
8. ^ RS Stephens, G. Myers u. a .: Divergence without difference: phylogenetics and taxonomy of Chlamydia resolved. In: FEMS immunology and medical microbiology. Vol. 55, No. 2, March 2009, pp. 115-119, ISSN  1574-695X . doi : 10.1111 / j.1574-695X.2008.00516.x . PMID 19281563 . (Review).
9. ^ G. Greub: International Committee on Systematics of Prokaryotes. Subcommittee on the taxonomy of the Chlamydiae: minutes of the inaugural closed meeting, 21 March 2009, Little Rock, AR, USA. In: International journal of systematic and evolutionary microbiology. Volume 60, No. 11, November 2010, pp. 2691-2693, ISSN  1466-5034 . doi : 10.1099 / ijs.0.028225-0 . PMID 21048221 .
10. ^ G. Greub: International Committee on Systematics of Prokaryotes. Subcommittee on the taxonomy of the Chlamydiae: minutes of the closed meeting, June 21, 2010, Hof bei Salzburg, Austria. In: International journal of systematic and evolutionary microbiology. Volume 60, No. 11, November 2010, p. 2694, ISSN  1466-5034 . doi : 10.1099 / ijs.0.028233-0 . PMID 21048222 .
11. ^ 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.  
12. ^ Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 191 (quoted).
13. ^ Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 191.