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Week Uno(1): History of Chlamydia trachomatis

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Week Uno(1): History of Chlamydia trachomatis

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It was discovered in 1907

Though discovered in 1907 there are references to chlamydia diseases that go back to ancient Egyptian and Chinese text

It was first mistaken to be a protozoan parasite and then a virusas considered a virus, the cytoplasmic inclusions of C. trachomatis were actually mistaken for a time to be a protozoan parasite

Discovered by Halberstaedter and Von Prowazek

﻿It was discovered in the scrapings of the eye of an experimental orangutan

Resources

Budai I. (2007). Chlamydia trachomatis: milestones in clinical and microbiological diagnostics in the last hundred years: a review. Acta microbiologica et immunologica Hungarica, 54(1), 5–22. https://doi.org/10.1556/AMicr.54.2007.1.2

Carolyn M. Black, 2013. "Introduction", Chlamydial Infection: A Clinical and Public Health Perspective, C.M. Black https://doi.org/10.1159/000348748

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phylogeny of C. trachomatis Figure 1 image of article of Harris et al.

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• Chlamydia trachomatis cause trachoma and sexually transmitted infections despite C. Trachomatis being a dangers human pathogen very little is known about the evolution of the strains that cause its disease (Metsa-Simola et al.)

Attempts have been made to reconstruct the C. trachomatis phylogeny using ompA sequences10, 16S ribosomal RNA (rRNA)gene analysis11, multilocus sequence typing (MLST) and there is no agreement made in the evolutionary relationships between the C. trachomatis strains (Harris et al.).

C. trachomatis comprises two biovars(groups)that include the ocular and urogenital strain's (Harris et al.).

5,026 strains have been reported in literature and found in 33 geographic regions in five different continents (Harris et al.).

The phylogeny of C. Trachomatis composes of 3 distinct lineages LGV, urogenital clade, and T1 and T2 that split from the urogenital strain.

Resources

Harris SR, Clarke IN, Seth-Smith HMB, et al. Whole-genome analysis of diverse Chlamydia trachomatis strains identifies phylogenetic relationships masked by current clinical typing. Nature Genetics. 2012;44(4):413-419. doi:10.1038/ng.2214

Metsä-Simola NS, Einiö EK, Martikainen PT. Changes in Chlamydia trachomatis risk before and after union formation and separation among women of reproductive age. European Journal of Public Health. 2024;34(5):890-894. doi:10.1093/eurpub/ckae074

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Taxonomy of the Chlamydiales. (Adapted from Bush and Everett, 2001.

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Week Tres (3) C. trachomatis Classification

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Week Tres (3) C. trachomatis Classification

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Chamydie were first believed to be viruses, but because they have a cell wall and contain DNA, RNA, and ribosomes are now classified to the bacteria domain (Becker, 1996)

It then divides into two biovars : Tracoma and LGV

The two biovars are then subdivided into 15-19 serotypes:

includes ocular serotypes A–C and the urogenital serotypes D–K, and the LGV biovar includes serotypes L1, L2, L3 and L2b

C. trachomatis infection caused by serovars L₁, L₂, and L₃ (also known as lymphogranuloma venereum, or LGV).

C. trachomatis ways of classifications are the following:

Kingdom: Bacteria

Phylum: Chlamydiae

Class: Chlamydiae

Order: Chlamydiales

Family: Chlamydiaceae

Genus: Chlamydia

Species:Chlamydia trachomatis

﻿﻿Determine how the agent is classified.

These bacteria are characterized by its biphasic developmental cycle of ∼48–72 h, where they morphologically switch between the extracellular infectious elementary body (EB) and the larger metabolically active noninfectious reticulate body (RB) that replicates within a host-cell inclusion (Schachter and Caldwell, 1980).

C. trachomatis is traditionally classified into 15 main serovars based on the differential serospecificity of the major outer membrane protein(MOMP) or polymorphism of ompA (that encodes MOMP) (Yuan et al., 1989).

C. trachomatis pathobiologic diversity has been a constant challenge due to its asynchronous life-cycle

Chlamydiae are Gram-negative, obligate intracellular human pathogen

C. trachomatis biphasic developmental cycle is responsible for its huge taxonomic confusion that involved not only their misclassification as protozoa or virus, but also the adoption of multiple misdesignations

﻿﻿Is it in Bergey's Manual?

Yes, C. trachomatis appears in the Bergey’s manual

Resources

Becker Y. Chlamydia. In: Baron S, editor. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston; 1996. Chapter 39. Available from: https://www.ncbi.nlm.nih.gov/books/NBK8091/

“Chlamydia Trachomatis Infection 2022 Case Definition.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 30 Aug. 2021, ndc.services.cdc.gov/case-definitions/chlamydia-trachomatis-infection-2022/.

Elsevier, B.V. “Chlamydia Trachomatis.” Chlamydia Trachomatis - an Overview | ScienceDirect Topics, 2025, www.sciencedirect.com/topics/agricultural-and-biological-sciences/chlamydia-trachomatis.

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C. trachomatis is classified as Gram-negative bacteria, with an cytoplasmic membrane and outer lipopolysaccharide membrane similar to Gram-negative bacteria but does not have an peptidoglycan wall.

the outer membrane contains MOMPs proteins, cystine proteins, and eukaryotic cell-binding proteins and more of course.

Chlamydiae exists as two stages: Elementary bodies and Reticulate bodies. The elementary body is an infectious, nonreplicating particle with a rigid outer membrane. Reticulate bodies which is its intracytoplasmic reproductive form.

In the elementary body it contains :

A DNA genome( about 600 genes)

DNA plasmid(7,498 base pairs)

Contains a gene for DNA replication

RNA polymerase

Ribosomes and ribosomal subunits

C. trachomatis lack many biosynthetic pathways and are entirely dependent on their host cell

It lack flagella and pilli

References

Becker, Yechiel. “Chlamydia.” Medical Microbiology. 4th Edition., U.S. National Library of Medicine, 1 Jan. 1996, www.ncbi.nlm.nih.gov/books/NBK8091/#:~:text=The%20outer%20chlamydial%20cell%20wall,share%20the%20same%20primary%20sequence.

“Chlamydia - Microbewiki - Kenyon College.” Microbewiki, Media Wiki, 26 July 2010, microbewiki.kenyon.edu/index.php/Chlamydia.

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For many years C. trachomatis has been considered an “energy parasite” that relies entirely on the of ATP from the host cell.

C. trachomatis has an active respiratory metabolism that is coupled to the sodium-dependent synthesis of ATP.

C. Trachomatis does not have flavoproteins and cytochromes, which are needed for the mitochondrial respiratory function

ATP-ADP translocases (Npt1 and Npt2) are found in C. trachomatis, which allow for ATP uptake from the host cell, supports the energy parasite hypothesis

Chlamydiae encode many pathways involved in energy metabolism, like an incomplete Karen’s cycle, glycolysis, and a pentose–phosphate pathway. The expression of these enzymes is activated at mid-stage of the infection.

-enzymes vary between the EB and RB forms

In the initial phase of the infection, the EBs depend on host-cell energy.

During the mid-stage of the developmental cycle RBs switch and depend to a limited extent on the host cells.

-because RBs are able to produce their own energy during mid-stage a Na⁺ gradient is essential for chlamydial infection and growth.

C. trachomatis is a heterotroph because it depends on s host cell

Resources

Liang, Pingdong et al. “Dynamic energy dependency of Chlamydia trachomatis on host cell metabolism during intracellular growth: Role of sodium-based energetics in chlamydial ATP generation.” The Journal of biological chemistry vol. 293,2 (2018): 510-522. doi:10.1074/jbc.M117.797209

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C. Trachomatis requires a eukaryotic host cell in order to grow and develop.

C. trachomatis, requires a temperature of 37 degrees to be incubated in a lab. 37 degrees is about human body temperature.

CT can grow in host cells regardless of O₂

-CT relies on the ATP from the host cells but when oxygen levels become low Ct can shift from getting its ATP from the mitochondria to glycolysis (Thalia et al., 2022).

Yes, C.trachomatis requires salt to grow, but in the form of sodium chloride. It requires a sodium gradient for it’s energy.

CT is a host dependent so that makes them hard to grow in a lab setting because they require mammalian cells (humans) to grow and survive.

- tissue culture system are used in labs to grow CT. Examples : HeLa cells(human cervical cells) McCoy cells( mouse fibroblast), Vero cells(African green monkey kidney cells).

-Chlamydia trachomatis can be identified microscopically in scrapings from the eyes or the urogenital tract

CT has a better chance at growth in a pH level of 7-7.5 slightly alkaline.

-The change in pH level from 6.26 to 7.25 in the chlamydial inclusion as infection is taking place indicates influx of H+ to RBs (Liang et al. 2017).

﻿﻿They are mesophlies because they grow in human body temperatures. They are also neutralphile because of its liking of a pH of 7.5.

Resources

Johnston, S L, and C Siegel. “Comparison of Buffalo green monkey kidney cells and McCoy cells for the isolation of Chlamydia trachomatis in shell vial centrifugation culture.” Diagnostic microbiology and infectious disease vol. 15,4 (1992): 355-7. doi:10.1016/0732-8893(92)90023-m

Liang, Pingdong et al. “Dynamic energy dependency of Chlamydia trachomatis on host cell metabolism during intracellular growth: Role of sodium-based energetics in chlamydial ATP generation.” The Journal of biological chemistry vol. 293,2 (2018): 510-522. doi:10.1074/jbc.M117.797209

Scidmore, Marci A. “Cultivation and Laboratory Maintenance of Chlamydia trachomatis.” Current protocols in microbiology vol. Chapter 11 (2005): Unit 11A.1. doi:10.1002/9780471729259.mc11a01s00

Thapa, J., Yoshiiri, G., Ito, K., Okubo, T., Nakamura, S., Furuta, Y., Higashi, H., & Yamaguchi, H. (2022, April 22). Chlamydia trachomatis requires functional host-cell mitochondria and NADPH oxidase 4/p38mapk signaling for growth in Normoxia. Frontiers. https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.902492/full

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Chlamydia trachomatis genome is made up a single circular chromosome double stranded DNA

-Number of nucleotides: 1042519
-Number of RNA genes: 45

-genome analysis identified 894 protein coding genes

C. trachomatis genomes size made up of a chromosome of 1.0 Mb (making it one of the smallest bacterial genomes)

Ct carry many highly conserved small 7.5-kb plasmids that hold both non-coding RNA of which the function is unknown, and 8 open reading frames (ORFs named pgp1 to pgp8)

-plasmid has been shown to encode genes essential for infection

CT genome has been mapped from back in 1959 .

No, CT has no antibiotic resistance genes, but genome sequencing has shown potential antibiotic resistance because of mutations.

Resources

KEGG GENOME: Chlamydia trachomatis D/UW-3/CX. (n.d.). https://www.genome.jp/kegg-bin/show_organism?org=ctr

Mestrovic, Tomislav, and Suncanica Ljubin-Sternak. “Molecular mechanisms of Chlamydia trachomatisresistance to antimicrobial drugs.” Frontiers in bioscience (Landmark edition) vol. 23,4 656-670. 1 Jan. 2018, doi:10.2741/4611

Mi, Yang et al. “Chlamydia trachomatisInhibits Homologous Recombination Repair of DNA Breaks by Interfering with PP2A Signaling.” mBio vol. 9,6 e01465-18. 6 Nov. 2018, doi:10.1128/mBio.01465-18

Seth-Smith, Helena M B et al. “Whole-genome sequences of Chlamydia trachomatis directly from clinical samples without culture.” Genome research vol. 23,5 (2013): 855-66. doi:10.1101/gr.150037.112

Stephens, Richard S., et al. “Genome Sequence of an Obligate Intracellular Pathogen of Humans: Chlamydia Trachomatis.” Science, vol. 282, no. 5389, 1998, pp. 754–59. JSTOR, http://www.jstor.org/stable/2899270. Accessed 6 Mar. 2025.

Versteeg, B., Bruisten, S. M., Pannekoek, Y., Jolley, K. A., Maiden, M. C. J., Van Der Ende, A., & Harrison, O. B. (2018). Genomic analyses of the Chlamydia trachomatis core genome show an association between chromosomal genome, plasmid type and disease. BMC Genomics, 19(1). https://doi.org/10.1186/s12864-018-4522-3

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﻿Chlamydia trachomatis does not have a capsule its a gram-negative bacteria that lacks peptidoglycan.Instead it has a very unique cell membrane.

-The outer membrane is twice as thick compared to other bacteria.

CT outer membrane has PMPs (polymorphic membrane proteins) which function as autotransporters, play a large role in adhesion, and serve as potent antigenic proteins.

-CT is known for its MOMP protein that makes up 60 % of the mass of the outer membrane of EBs(elementary body). MOMP is believed to play a role in pathogenesis and adhesion.

﻿﻿CT does not have Antibiotic resistance genes. But resistance can occur if there is a mutation in the 23S rRNA gene which leads to macrolide(a type of antibiotic) resistance

CT does not produce toxins like other bacteria but does have toxin like factors.

-CPAF (Chlamydia Protease-like Activity Factor) prevents the host from proper immune response. C. trachomatis use of CPAF targets proteins that restructure the Golgi apparatus and activate DNA repair so that able to use the host cell machinery and proteins.

C. trachomatis uses T3SS to deliver virulence effector proteins into host cells

Exoenzymes which is not a classical exoenzyme is CPAF which helps degrade host cell proteins.

﻿﻿CT has developed many different ways of evading host immune system.

-CT lives in vacuoles, called inclusion bodies which protect it from the humoral immune response.

CT also uses CPAF to keep host cell alive longer to complete replication

CPAF also degrades MHC class I and II molecules of infected host making hard to be detected

Resources

Benamri, I., Azzouzi, M., Sanak, K. et al. An overview of genes and mutations associated with Chlamydiae species’ resistance to antibiotics. Ann Clin Microbiol Antimicrob 20, 59 (2021). https://doi.org/10.1186/s12941-021-00465-

Byrne, Gerald I. “Chlamydia trachomatis strains and virulence: rethinking links to infection prevalence and disease severity.” The Journal of infectious diseases vol. 201 Suppl 2,Suppl 2 (2010): S126-33. doi:10.1086/652398

Vasilevsky, Sam et al. “Chlamydial polymorphic membrane proteins: regulation, function and potential vaccine candidates.” Virulence vol. 7,1 (2016): 11-22. doi:10.1080/21505594.2015.1111509

Wang, Xinglv et al. “Insights into innate immune cell evasion by Chlamydia trachomatis.” Frontiers in immunologyvol. 15 1289644. 25 Jan. 2024, doi:10.3389/fimmu.2024.1289644

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Chlamydia trachomatis is treated with chemotherapies which are antibiotics.

Doxycycline

-an antibiotic for seven days

Azithromycin

-is a one time dose recommended for CT infected pregnant women

Alternatives are

-Erythromycin 500mg orally four times a day

-Erythomycin ethylsuccinate 800 mg orally four times per day

-Oflaxacin 300mg twice per day

-Levofloxacin 500mg once per day

CT can be cured after taking antibiotics as recommended by physician

-some sexually transmitted STI’s are starting to become resistant to antibiotics important to take antibiotics until prescription is finished.

Side effects for taking antibiotics are feeling sick, diarrhea, stomachache, and vaginal yeast infection.

(side effects dont apply to everyone)

The CDC recommends retesting if symptoms are persistent

reinfection is a common problem

Resources

Chlamydia. (2025, March 19). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/4023-chlamydia

Chlamydia trachomatis - Diagnosis and treatment - Mayo Clinic. (n.d.). https://www.mayoclinic.org/diseases-conditions/chlamydia/diagnosis-treatment/drc-20355355#:~:text=Chlamydia%20trachomatis%20is%20treated%20with,Request%20an%20appointment

Miller, K. E. (2006, April 15). Diagnosis and Treatment of Chlamydia trachomatis Infection. AAFP. https://www.aafp.org/pubs/afp/issues/2006/0415/p1411.html

Understanding Chlamydia: Diagnosis and treatment. (2023, November 30). WebMD. https://www.webmd.com/sexual-conditions/understanding-chlamydia-treatment

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Biochemistry of Chlamydia trachomatis relies on its host cells for its metabolic pathways:

Genomic data show CT uses many pathways for energy Metabolism like glycolysis, an incomplete Krebs cycle, and a Pentose-phosphate pathway.

-The expression of a glycolysis enzyme differs between CTs EB and RB forms indicating different energy strategies for each phase.

-genomic data show CT contains enzymes of a simplified ETC compared to the mitochondrial chain. CTs ETC depends on a sodium gradient.

-C. trachomatis imports amino acids from the host cell for protein biosynthesis.

-CT requires an exogenous supply of amino acids that takes from its host cells

-CT rely on host cells lipids for survival and has efficient methods to obtain.

The unique EB and RB forms of CT

-EB is the metabolically inactive phase of Ct.

-RB is the metabolically active phase of CT

﻿﻿What biochemical tests is your agent positive for?

Since CT cannot grow on standard culture media Biochemical test like catalase, oxidase, or carbohydrate fermentation are not fitting.

Nucleic Acid Amplification (NAAT)Test

-NAAT is the the test of choice for CT replacing cultures as diagnostics .

-Antigen test (EIA, DFA, RDTs) are no longer pushed due to inaccuracy.

-NAATs are the most sensitive and high specificity.

Direct Fluorescent Antibody(DFA) Test

-Test is directly performed on clinical specimen and it uses fluorescent-labeled antibodies directed against C. trachomatis LPS or MOMP to detect CT inclusions.

-Using this test has led to 98-99% specificity and 80-90% sensitivity compared to cell cultures.

-the high specificity by the DFA test is in part to being able to visualize morphology and staining properties of CT inclusions.

Enzyme immunoassays(ELISA) are test for the detection of LPS specific antigens.

-downside to test is cross-reaction of LPS-specific antibodies to other gram-negative bacteria can give false reading.

Cell cultures are rarely used now a days. When cells are cultured it requires host cells like McCoy or HeLa cells for growth. Inclusion bodies can be stained.

Resources

Elwell, Cherilyn A, and Joanne N Engel. “Lipid acquisition by intracellular Chlamydiae.” Cellular microbiology vol. 14,7 (2012): 1010-8. doi:10.1111/j.1462-5822.2012.01794.x

Mehlitz, A., Eylert, E., Huber, C., Lindner, B., Vollmuth, N., Karunakaran, K., Goebel, W., Eisenreich, W. and Rudel, T. (2017), Metabolic adaptation of Chlamydia trachomatis to mammalian host cells. Molecular Microbiology, 103: 1004-1019. https://doi.org/10.1111/mmi.13603

Meyer, Thomas. “Diagnostic Procedures to Detect Chlamydia trachomatis Infections.” Microorganisms vol. 4,3 25. 5 Aug. 2016, doi:10.3390/microorganisms4030025

Thapa, J., Yoshiiri, G., Ito, K., Okubo, T., Nakamura, S., Furuta, Y., Higashi, H., & Yamaguchi, H. (2022, April 22). Chlamydia trachomatis requires functional host-cell mitochondria and NADPH oxidase 4/p38mapk signaling for growth in Normoxia. Frontiers. https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.902492/full

Shetty, Seema et al. “Diagnosis of Chlamydia trachomatis genital infections in the era of genomic medicine.” Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology] vol. 52,3 (2021): 1327-1339. doi:10.1007/s42770-021-00533-z

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NAATs are the preferred diagnostic test to used due to its accuracy and easier to use.

-For men is urine samples or urethral swabs

-women is vaginal/cervical swabs or urine

The accuracy of NAATs on urine samples is equivalent to samples obtained directly from the cervix or urethra.

﻿﻿Research diagnostic tests used to detect the agent.

PCR (polymerase chain reaction) is a test that uses a polymerase chain reaction technique. PCR is a type of nucleic acid amplification test (NAAT).

NAATs test are based on the amplification of specific CT sequences by using PCR and LCR(less common).

-amplification allows NAATSs to detect one CT microbe per assay versus conventional methods is 100 to 1,000

-PCR test detects plasmid DNA

Enzyme immunoassay (EIAs) and Rapid diagnostic test (RDTs) for the detection of CT antigens unsuitable due to insufficient sensitivity and specificity.

RT-PCR (Real Time-PCR) is being used more and more in recent years. It’s easier to perform in a closed-tube format is less prone to contamination. Test are limited in resource-poor countries. Usually used in research setting.

﻿﻿ELISA (Enzyme-Linked Immunosorbent Assay) is a type of serological test.

-serological test ( antigens or antibodies) in CT diagnosis is very limited, because the CT antibody response is either delayed or absent in some individuals.

Resources

Centers for Disease Control and Prevention. (2021, July 22). Chlamydial infections - STI treatment guidelines. Centers for Disease Control and Prevention. https://www.cdc.gov/std/treatment-guidelines/chlamydia.htm#:~:text=For%20women%2C%20C.,meatal%20swab%20over%20providing%20urine.

Dhawan, Benu et al. “Diagnostic efficacy of a real time-PCR assay for Chlamydia trachomatis infection in infertile women in north India.” The Indian journal of medical research vol. 140,2 (2014): 252-61.

Gaydos, Charlotte A et al. “Comparison of three nucleic acid amplification tests for detection of Chlamydia trachomatis in urine specimens.” Journal of clinical microbiology vol. 42,7 (2004): 3041-5. doi:10.1128/JCM.42.7.3041-3045.2004

Meyer, Thomas. “Diagnostic Procedures to Detect Chlamydia trachomatis Infections.” Microorganisms vol. 4,3 25. 5 Aug. 2016, doi:10.3390/microorganisms4030025

Mishori, R., McCLASKEY, E. L., & Winklerprins, V. J. (2012, December 15). Chlamydia trachomatis infections: Screening, diagnosis, and Management. American Family Physician. https://www.aafp.org/pubs/afp/issues/2012/1215/p1127.html#:~:text=Nucleic%20acid%20amplification%20tests%20(NAATs,detecting%20chlamydia%20and%20gonococcal%20infections.&text=NAATs%20can%20be%20performed%20on,first%2Dvoid%20is%20preferred).&text=The%20accuracy%20of%20NAATs%20on,from%20the%20cervix%20or%20urethra.&text=On%20wet%20mount%2C%20a%20finding,gonococcal%20infections%20of%20the%20cervix.&text=Oropharyngeal%20and%20rectal%20swabs%20may,receptive%20oral%20or%20anal%20intercourse.&text=Point%2Dof%2Dcare%20testing%20at,sensitivity%20and%20specificity%20than%20NAATs.

Shetty, Seema et al. “Diagnosis of Chlamydia trachomatis genital infections in the era of genomic medicine.” Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology] vol. 52,3 (2021): 1327-1339. doi:10.1007/s42770-021-00533-z

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Chlamydia trachomatis is a common sexually transmitted disease and any one can get infected that is of course if they are sexually active.

CT is transmitted during oral, vaginal, and anal sex with a person that is infected.

-wearing a condom can lower risk of infection.

CT can also be transmitted to baby during child birth.

Chlamydia is spread by direct transmission

-CT is transmitted by direct sexual contact (even sex with no penetration or ejaculation).

-vaginal fluid or semen that comes in contact with a person can cause infection (including eyes)

-CT is passed when the mucous membranes comes in contact with mucous membranes, secretions, or semen of infected person.

﻿﻿Indirect transmission

- You cannot get chlamydia from casual contact.

Ex: hugging, shaking hands, kissing, sharing utensils, or using the same toilet seat, hot tubs.

CT cannot be transmitted by ﻿﻿Fomites (objects)

-CT dies quickly outside body therefore cannot be spread through objects

Vectors such as flies transmit disease cause trachoma (eye infection) in areas with poor sanitation this transmission is rare.

Resources

Chlamydia: Causes, symptoms, treatment & prevention. Cleveland Clinic. (2025, March 19). https://my.clevelandclinic.org/health/diseases/4023-chlamydia

NCC. (n.d.). How is chlamydia transmitted?. Chlamydia Coalition. https://chlamydiacoalition.org/chlamydia-101/transmission/#:~:text=Chlamydia%20can%20be%20passed%20when%20the%20mucous,a%20condom)%20whether%20vaginal%20or%20anal%20sex.

Signs & symptoms of chlamydia: Chlamydia prevention. OHHPC. (2024, August 8). https://endinghivoklahoma.org/chlamydia/#:~:text=How%20the%20Bacteria%20Spreads,or%20pneumonia%20in%20the%20newborn.

World Health Organization. (n.d.). Trachoma. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/trachoma#:~:text=Based%20on%20April%202024%20data,nose%20of%20an%20infected%20person.

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Week Dose(12) Pathology and Immune Response

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Week Dose(12) Pathology and Immune Response

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﻿﻿Chlamydia trachomatis shows many forms of pathologies like

-cervicitis in women

-PID in women resulting in ectopic pregnancy and chronic pelvic pain

-urethritis in men

- epididymitis

-reactive arthritis

It’s important to note that many people infected with C. trachomatis show no signs of infection

CT when left untreated is when it leads to symptoms.

Symptoms in women include:

-burning sensation when urinating

-change in virginal discharge (strong smell)

-Bleeding after sexual intercourse

-bleeding in between periods

-pain or discomfort in lower abdomen

-itchiness

-pain during intercourse

Symptoms in men include:

-pain in testicles (one or both testicles)

-discharge from penis (clear or cloudy)

-burning sensation when urinating

Symptoms for oral infections are asymptomatic

Infection is transmitted from mother to babies eyes at birth

Because CT is asymptomatic regular screening is recommended

If CT infection is left untreated significant damage can be made. Damage is greater in women when infection is left untreated even with no symptoms.

-women can develop pelvic inflammatory disease (PID). Which is a serious infection of the women’s reproductive organs.

-abdominal and pelvic pain

-infertility and ectopic pregnancy

In men the damage Of CT is pain in testicles.

-in rare cases can lead to infertility

Can cause arthritis symptoms

CT can cause conjunctivitis of the eye

﻿﻿Immune response to CT

-is both innate and adaptive immunity

Innate Immune Response

- Mucosal barrier is first line of defense for CT

-Next step of immune defense that is not our usual innate immune response are the epithelial cells which can initiate an immune response.

Natural Killer Cells(NK) and neutrophils are the first immune cells to site of infection. Followed by DC (dendritic cells).

-NK are put to work when chemokines are secreted

-Neutrophils are able to reduce direct infection and limit spreading

-DC cells antigen presenting cells that as immature cells receive signal of pathogen invasion travel to lymph nodes go through a process to activate T-cells.

-Interferon y plays important role in innate and adaptive immunity and inhibiting CT growth. Also plants a role in T-helper cell immune response.

-Macrophages travel to infection site and phagocytose bacteria. Depending on receptor match they induce various effectors to produce pro-inflammatory cytokines.

Adaptive Immunity is needed to limit spreading of infection and protection against reinfections.

-T-lymphocytes and B-lymphocytes help regulate this immune response

- B-lymphocytes (B cells) regulate humoral immune response making antigens against foreign antigens.

CT induces both cell-mediated and humoral immune response.

-CT cell-mediated immune response T cells (helpers cells) play a critical role in innate CT infection clearance.

﻿﻿Does it cause autoimmunity?

-There has been some studies that have showed in some cases a link between CT and reactive arthritis.

-joint swelling/pain

-painful urination

-eye inflammation

Resources

Celine Lamacchia, Romain Aymon, Brian C Hattel, Sebastien Aeby, Carole Kebbi-Beghdadi, Benoit Gilbert, Olivia Studer, Jill M Norris, V Michael Nolers, M Kristen Demoruelle, Marie L Feser, Laura Kay Moss, Delphine S Courvoisier, Kim Lauper, Kevin D Deane, Gilbert Greub, Axel Finckh, A potential role for chlamydial infection in rheumatoid arthritis development, Rheumatology, Volume 64, Issue 1, January 2025, Pages 252–260, https://doi.org/10.1093/rheumatology/kead682

Helble, Jennifer D, and Michael N Starnbach. “T cell responses to Chlamydia.” Pathogens and disease vol. 79,4 (2021): ftab014. doi:10.1093/femspd/ftab014

O'Connell, Catherine M, and Morgan E Ferone. “Chlamydia trachomatis Genital Infections.” Microbial cell (Graz, Austria) vol. 3,9 390-403. 5 Sep. 2016, doi:10.15698/mic2016.09.525

Redgrove, Kate A, and Eileen A McLaughlin. “The Role of the Immune Response in Chlamydia trachomatis Infection of the Male Genital Tract: A Double-Edged Sword.” Frontiers in immunology vol. 5 534. 27 Oct. 2014, doi:10.3389/fimmu.2014.00534

World Health Organization. (2024, November 24). Chlamydia. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/chlamydia#:~:text=Oral%20infection%20is%20most%20often,or%20pain%20while%20passing%20stools.

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﻿﻿Chlamydia is the most common STI in the United States

CT is the most common cause of sexually transmitted infections in the world

The increase in infections is of concern to population.

-high prevalence rates urges population for regular screenings in high-risk population

﻿CT’s global prevalence in women is 4.0% and 2.5% in men

-estimated 128.5 million new cases world wide

-infection is most common in young people

-prevalence estimates are the highest in the Americas

CT’s morbidity is extremely high with millions of cases occurring every year.

-true numbers are estimated to be much higher

-in 2023 1,648,568 cases of Chlamydia reported

-492.2 per 100,000 rate of reported Chlamydia

-Chlamydia is asymtimatic reason for lower diagnosis

C. trachomatis mortality rate is 0.1 deaths per 100,000 women

-deaths occur from CT complications like ectopic pregnancy

﻿﻿CT is a notifiable disease to the CDC

through the National Notifiable Diseases Surveillance System (NNDSS)

Resources

National Overview of STIs in 2023. (2024, November 12). STI Statistics. https://www.cdc.gov/sti-statistics/annual/summary.html#:~:text=In%202023%2C%20a%20total%20of%201%2C648%2C568%20cases%20of%20Chlamydia%20trachomatis,initial%20shelter%20in%20place%20orders.

McElligott, Kara A. “Mortality from sexually transmitted diseases in reproductive-aged women: United States, 1999-2010.” American journal of public health vol. 104,8 (2014): e101-5. doi:10.2105/AJPH.2014.302044

Mohseni, M., Sung, S., & Takov, V. (2023, August 8). Chlamydia. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK537286/#:~:text=Epidemiology,20%2D24%20years%20of%20age.

Sexually Transmitted Disease (STD) surveillance - Health, United States. (n.d.). https://www.cdc.gov/nchs/hus/sources-definitions/std.htm#:~:text=Case%20data%20are%20available%20for,chlamydia%2C%20gonorrhea%2C%20and%20syphilis.

World Health Organization: WHO & World Health Organization: WHO. (2024, November 21). Chlamydia. https://www.who.int/news-room/fact-sheets/detail/chlamydia#:~:text=Scope%20of%20the%20problem,nose%2C%20particularly%20among%20young%20children.

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Case Study on inclusion conjunctivitis caused by C. trachomatis

1. Background:

A 24 year old male college student comes into clinic with red eyes, watery discharge, irritation, and blurred vision for four weeks.

-No contact lenses use

-No recent injury

-No previous eye surgery

-No other eye diseases

-No recent travel

-No contact with chemicals

-No contact with animals

-No contact with plants

On examination vision is at 20/20 with normal eye pressure. Has gone to other clinics for recurrent pink eye and topical antibiotics have been prescribed in the past. Therefore acute on chronic conjunctivitis has been diagnosed. Topical corticosteroids and anti-histamine eye solutions have been prescribed.

2. Problem:

Patient has returned earlier than post op appointment time. Patient is now complaining of more irritation to the eyes, and loss of vision on the right eye. Vision on the right eye has declined to 20/40. Under lamp sub-epithelial corneal infiltrations have been observed in the right eye. Severe congestion and follicular reaction involving bulbar conjunctiva have been observed.

3. Objectives:

The objective is to diagnose the cause of the symptoms. Patients med-history is being dived into including updated medication use, tobacco exposure, and sexual exposure. Patient has denied having multiple partners but did mention that girl friend was treated recently for Chlamydia and Gonorrhea. .

4. Solutions:

Suspicion of Chlamydia infection so conjunctival lavage has performed with sterile saline. Lavage samples have been collected and urine samples . Samples sent to laboratory for cytology and RT-PCR examination. Both samples reveled positive results. Lavage sample was also collected for Giemsa- stain that is used for intracytoplasmic inclusions. Inclusions have been observed in stain. Patient was prescribed doxycycline 100mg twice a day for ten days. Topical ointments have been also prescribed Fluoroquinolone four times a day and tetracycline twice day.

5. Results:

Patients symptoms have improved. Vision on right eye is 20/20 and patient has been referred to infectious department for further evaluations.

The takeaway from this study is that if an individual is sexually active regular screening is recommended.

Resources

Lee , W.-J. L. A., & Chen, C.-C. (2021, December 18). Adult inclusion conjunctivitis diagnosed by polymerase chain reaction and Giemsa stain. IDCases. https://www.sciencedirect.com/science/article/pii/S2214250921003231