Campylobacter coli

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Campylobacter coli
Systematics
Department : Proteobacteria
Class : Epsilonproteobacteria
Order : Campylobacterales
Family : Campylobacteraceae
Genre : Campylobacter
Type : Campylobacter coli
Scientific name
Campylobacter coli
( Doyle 1948) Véron & Chatelain 1973

Campylobacter coli is a microaerophilic , gram-negative bacterium from the genus Campylobacter . It is closely related to Campylobacter jejuni , both species were previouslyassigned tothe genus Vibrio and are the pathogens of Campylobacter enteritis , an inflammatory diarrheal disease in humans. They are transmitted from animals to humans through food and drinking water.

The species comprises about 90 strains . The genome of several strains was fully sequenced in 2013 . In addition to the bacterial chromosome , the cell can also contain plasmids . An investigated plasmid contains several genes for antibiotic resistance and thus gives the bacterium resistance to gentamycin and other antibiotics .

features

Appearance

The cells of Campylobacter coli are slender, spirally curved rods, which 0.2-0.8  micrometers (microns) thick and 1-5 are microns long. There are also comma-shaped curved rods. There is a single at both poles scourge , characterized one is active movement of cells possible. They behave negatively in the Gram coloring . There are no persistence forms such as endospores .

Growth and metabolism

Campylobacter coli is a microaerophilic bacteria. It needs oxygen for growth, but in lower concentrations than those found in the air. It has an aerobic metabolism and is catalase- positive and oxidase- positive. A gas atmosphere that contains less oxygen (O 2 ) and more carbon dioxide (CO 2 ) than the air is often used for cultivation . A gas mixture used for this purpose consists of 5% O 2 , 10% CO 2 and 85% nitrogen (N 2 ). A similar gas atmosphere used in the study of Campylobacter coli contains 5% O 2 , 3.5% CO 2 , 7.5% hydrogen (H 2 ) and 84% N 2 . The incubation usually takes place at 37 ° C, with growth still taking place at 42 ° C, but not at 25 ° C. It is counted among the thermophilic Campylobacter species .

Some enzymes that are used in the metabolism to break down certain substrates, as well as other metabolic reactions, are detected as part of a " colorful series " in order to identify a bacterium. Campylobacter coli has catalase and oxidase and can reduce nitrate to nitrite with the help of the enzyme nitrate reductase (NADH) ( EC 1.7.1.1) . It can grow in a nutrient medium that contains up to 1% glycine and tolerates a proportion of glucose in the medium of up to 8%. An important feature for differentiating the various Campylobacter species is the test for the formation of hydrogen sulfide (H 2 S). This test can be carried out with TSI agar ( Triple Sugar Iron Agar , English for triple sugar iron agar). Here is Campylobacter coli inconclusive, d. H. there may be a positive or negative result in the test. Alpha hemolysis can be observed on culture media that contain an addition of blood (a so-called blood agar ) .

The bacterium's resistance to antibiotics is important for its effect as a pathogen . In the USA , the bacterial strains from clinical samples have been tested for resistance to aminoglycoside antibiotics at regular intervals since 2002 and also from meat samples from retail stores since 2002 . As a result of this monitoring , a gentamycin- resistant Campylobacter coli (isolated from a human) was discovered in 2000 , which was followed by an isolate from chicken meat in 2007. In 2010, 11.3% of the strains isolated from humans and 12.5% ​​of the strains isolated from meat samples were resistant to gentamicin. The insensitivity to nalidixic acid , the first antibiotic from the group of quinolone antibiotics , was already described in 1973 by Véron and Chatelain . They succeeded in culturing on blood agar with an addition of 40 µg / ml of nalidixic acid.

genetics

The genome of three strains has already been completely sequenced (as of 2013). The Campylobacter coli CVM N29710 bacterial strain used for a study was isolated from a retail poultry meat sample. The genome of the bacterial chromosome is 1673 kilobase pairs (kb) in size  , which is about 35% of the genome size of Escherichia coli . In addition to the chromosomes, two plasmids were also sequenced, the smaller 3.7 kb and the larger 55.1 kb. A total of 1694 proteins are annotated . The results of the sequencing show a GC content (the proportion of the nucleobases guanine and cytosine ) in the bacterial DNA between 31.4 and 31.9 mol percent. This is within the range of 30-38 mol percent which is typical of the genus Campylobacter , a member of the class of Epsilonproteobacteria . Campylobacter coli and some related species were previously included in the Vibrio genus . These bacteria, which belong to the class of Gammaproteobacteria, have a significantly higher GC content, e.g. B. 47 mole percent in Vibrio cholerae . This proves that Campylobacter coli is not closely related to the Vibrios.

The investigation of the strain isolated from poultry meat also includes the plasmids present in the genome. One of the two plasmids contains several genes for antibiotic resistance and thus gives the bacterium resistance to several aminoglycoside antibiotics (gentamycin, kanamycin , streptomycin , streptothricin ) and tetracyclines . The plasmid can be transferred from one bacterial cell to the next, which means that the resistance genes are also transferred.

Pathogenicity

Campylobacter coli is  assigned to risk group 2 by the Biological Agents Ordinance in conjunction with the TRBA ( Technical Rules for Biological Agents) 466 and marked as a zoonotic agent . This indicates the possibility that an infection can be transmitted directly or indirectly between animals and humans.

The mechanisms of pathogenicity of the pathogen are still the subject of research. Campylobacter coli forms the so-called cytolethal distending toxin (CDT), roughly translated as cytolethal (deadly for cells), inflating toxin . This toxin consists of several subunits, one of which shows DNase activity and is therefore able to break down DNA . The CDT intervenes in the process of cell division , which leads to enlarged cells that appear bloated. The toxin is named after this phenomenon. The genes coding for this virulence factor cdtA, cdtB and cdtC were the subject of a study published in 2010. 242 isolates from food and 112 isolates from clinical samples were examined for these genes. All three genes could be detected in all bacterial strains from the clinical samples; in the food isolates the cdtA and cdtC genes were detected in 99.4% of the strains and the cdtB gene in 98.8% of the strains.

proof

Campylobacter coli is usually cultivated on or in complex nutrient media. These contain, for example, meat extract or yeast extract , peptone and sodium chloride (NaCl). This medium can also be mixed with 10% blood. Müller-Hinton agar with an addition of 5% horse blood is also suitable for cultivation . The addition of blood makes it possible to assess whether the bacterium is hemolytic. The colonies grown on these nutrient media must be further examined for identification. Biochemical tests for identification include the catalase and oxidase test, as well as typical tests from a "colorful series". A rapid determination system based on this in miniature format ( Analytical Profile Index ) for the determination of Campylobacter species is commercially available.

Serological tests based on the antigen-antibody reaction can also be used for identification . The antibodies required are obtained from the blood serum of mice that have been immunized with purified membrane proteins of the Campylobacter species. However, the antibodies are not specific for a single antigen. The detection of certain parts of the bacterial genome with the help of the PCR method ( polymerase chain reaction ) is more specific . A gene typical for the genus is determined in addition to genes typical for the species . The detection takes place with the help of the multiplex PCR procedure and enables the differentiation of Campylobacter coli and Campylobacter jejuni .

Occurrence

Campylobacter coli is usually found in the intestines of pigs and poultry and other bird species . Occasionally it can also be detected in the human intestine. In sheep and cattle , it is usually not part of the intestinal flora .

Systematics

External system

Campylobacter coli is a typical representative of the genus Campylobacter . In addition to him, the species C. jejuni and C. lari are of medical importance for humans, while C. fetus is more of veterinary importance. Campylobacter coli and Campylobacter jejuni are closely related to one another and are similar in numerous features, so that a distinction depending on the examination method is not always possible. This is why they are sometimes recorded together as Campylobacter jejuni in medical microbiology . For another species - Campylobacter hyoilei - it is not yet clear whether it will retain its status as a separate species or whether it is a variant of Campylobacter coli .

Only in 1973 was it possible to reliably differentiate between Campylobacter and Vibrio species; before that, Campylobacter coli was known as Vibrio coli . This is based on the appearance of the cells, which, in addition to the spiral shape, also appear as comma-shaped bent rods, which is typical for Vibrionen.

Internal system

The species includes about 90 tribes . The genome of several strains has already been completely sequenced or is being researched in further genome projects. Campylobacter coli ATCC 33559 is the species typical strain. The strains examined so far in more detail have two plasmids ( Campylobacter coli CVM N29710), one plasmid ( Campylobacter coli 15-537360) or no plasmid ( Campylobacter coli 76339).

etymology

The generic name refers to the appearance of the bacterial cells ( ancient Greek καμπὓλος kampylos = crooked, βακτηρΐα bacteria = rod), i.e. to curved or bent rods. The species name refers to the occurrence, coli from Latin means "of the intestine" ( genitive ), thus refers to the intestine as a habitat .

Medical importance

Sources of infection

The infection of Campylobacter coli is usually orally , in most cases, the recording is done via contaminated food and drinking water . Infections when bathing in contaminated surface waters (bathing lakes and other stagnant bodies of water in summer) also occur. Direct fecal-oral transmission from person to person is rare. Individual cases of transmission from sick people to others in a communal facility are documented; permanent dropouts are normally not to be expected. However, long-term elimination can occur in immunocompromised people. Direct smear infection also occurs, especially in children. The infection often occurs in summer.

The bacteria can survive in the environment or in food for some time, but they do not multiply in the process. The ingestion of a relatively small amount of Campylobacter coli is sufficient to cause an infection; in children this is already possible with an infection dose of around 500 bacterial cells. The foods identified as sources of infection are mainly contaminated by excreted animals. In case studies, insufficiently heated or contaminated poultry meat has been identified as the main source of infection. Other sources of infection are unpasteurized milk, contaminated, untreated drinking water and raw minced meat . Transmission through pets (especially puppies and cats with diarrhea) or through contact with their excretions ( feces ) is possible.

Infectious diseases

After an incubation period of 1 to 7 days, the following symptoms may become noticeable:

In Germany and Austria there is a reporting obligation, in Germany the Infection Protection Act (IfSG) applies . According to Section 7 of the Infection Protection Act, there is an obligation to report positive pathogen detection by the verifying laboratory with the patient's name. According to § 6 IfSG, the disease must also be reported as acute infectious gastroenteritis if an epidemic connection is likely or suspected. According to Section 42 IfSG, the person concerned is prohibited from working in certain food establishments.

therapy

Most infections are self-limiting after a few days. Under certain circumstances, antibiotics are required, here erythromycin is the drug of choice. Quinolone antibiotics are only moderately effective.

Individual evidence

  1. ↑ a b c d 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. 540-541, 544, 556, 1108-1109.
  2. ^ Jan M. Hunt, Carlos Abeyta, Tony Tran: Bacteriological Analytical Manual, chapter 7: Campylobacter. In: Website of the Food and Drug Administration (FDA). Retrieved November 19, 2013 .
  3. ↑ a b c d e f g M. Veron, R. Chatelain: Taxonomic Study of the Genus Campylobacter Sebald and Veron and Designation of the Neotype Strain for the Type Species, Campylobacter fetus (Smith and Taylor) Sebald and Veron. In: International Journal of Systematic Bacteriology. Volume 23, No. 2, April 1973, pp. 122-134, doi : 10.1099 / 00207713-23-2-122 .
  4. ↑ a b c P. Vandamme, LJ Van Doorn u. a .: Campylobacter hyoilei Alderton et al. 1995 and Campylobacter coli Véron and Chatelain 1973 are subjective synonyms. In: International journal of systematic bacteriology. Volume 47, Number 4, October 1997, pp. 1055-1060, ISSN  0020-7713 . PMID 9336905 .
  5. ^ A b P. L. Griffiths, GS Moreno, RW Park: Differentiation between thermophilic Campylobacter species by species-specific antibodies. In: The Journal of applied bacteriology. Volume 72, Number 6, June 1992, pp. 467-474, ISSN  0021-8847 . PMID 1322880 .
  6. ↑ a b Y. Chen, S. Mukherjee u. a .: Whole-genome sequencing of gentamicin-resistant Campylobacter coli isolated from US retail meats reveals novel plasmid-mediated aminoglycoside resistance genes. In: Antimicrobial agents and chemotherapy. Volume 57, Number 11, November 2013, pp. 5398-5405, ISSN  1098-6596 . doi : 10.1128 / AAC.00669-13 . PMID 23959310 . PMC 3811239 (free full text).
  7. ↑ a b c d Campylobacter coli. In: National Center for Biotechnology Information (NCBI) Genome website . Retrieved November 20, 2013 .
  8. ↑ 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. Retrieved November 17, 2013 .
  9. ↑ Lawrence A. Dreyfus: Cytolethal Distending Toxin . In: Drusilla L. Burns et al. a. (Ed.): Bacterial Protein Toxins . 1st edition. ASM Press, Washington, DC 2003, ISBN 978-1-55581-245-4 , pp. 257-270 .
  10. ↑ M. Fernandes, C. Mena et al. a .: Study of cytolethal distending toxin (cdt) in Campylobacter coli using a multiplex polymerase chain reaction assay and its distribution among clinical and food strains. In: Foodborne pathogens and disease. Volume 7, Number 1, January 2010, pp. 103-106, ISSN  1556-7125 . doi : 10.1089 / fpd.2009.0326 . PMID 19821742 .
  11. ↑ API® biochemical identification (API Campy); Campylobacter species. (No longer available online.) In: website of bioMérieux Deutschland GmbH . Archived from the original on January 5, 2014 ; Retrieved November 19, 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. @1@ 2Template: Webachiv / IABot / www.biomerieux.de
  12. ↑ A. Al Amri, AC Senok et al. a .: Multiplex PCR for direct identification of Campylobacter spp. in human and chicken stools. In: Journal of medical microbiology. Volume 56, Number 10, October 2007, pp. 1350-1355, ISSN  0022-2615 . doi : 10.1099 / jmm.0.47220-0 . PMID 17893173 .
  13. ↑ a b c ECDC: Epidemiological Annual Report 2012 with data for 2010 and 2011 (in English). (PDF; 10.0 MB) In: Website of the ECDC ( European Center for Disease Prevention and Control ). Retrieved November 20, 2013 .
  14. ^ A b c Herbert Hof, Rüdiger Dörries: Dual series: Medical microbiology . 3. Edition. Thieme Verlag, Stuttgart 2005, ISBN 978-3-13-125313-2 , p. 305, 335-336 .
  15. ^ A b c Jean Euzéby, Aidan C. Parte: Genus Campylobacter. (No longer available online.) In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Archived from the original on November 3, 2013 ; Retrieved November 20, 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. @1@ 2Template: Webachiv / IABot / www.bacterio.net
  16. ↑ Taxonomy Browser Campylobacter coli. In: National Center for Biotechnology Information (NCBI) website . Retrieved November 20, 2013 .
  17. ↑ a b c d e f Campylobacter infections - RKI guide for doctors. In: Website of the Robert Koch Institute (RKI). August 17, 2011, accessed November 20, 2013 .
  18. ↑ Text of the Infection Protection Act (IfSG) at juris. Retrieved November 19, 2013.