Chlamydia trachomatis, an
obligate intracellularIntracellular parasites are parasitic microorganisms that are capable of growing and reproducing inside the cells of a host.-Facultative:Facultative intracellular parasites are capable of living reproducing inside or outside cells....
human pathogen, is one of three
bacteriaThe bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
l species in the
genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
ChlamydiaChlamydia refers to a genus of bacteria that are obligate intracellular parasites . Many of the chlamydia species are pathogenic....
.
C. trachomatis is Gram-indeterminate (i.e. cannot be stained with the
Gram stainGram staining is an empirical method of differentiating bacterial species into two large groups based on the chemical and physical properties of their cell walls...
); structurally the organism is
Gram-negativeGram-negative bacteria are those bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
. Identified in 1907,
C. trachomatis was the first chlamydial agent discovered in humans.
C. trachomatis includes three human
biovarA biovar is a variant prokaryotic strain that differs physiologically and/or biochemically from other strains in a particular species. Morphovars are those strains that differ physiologically. Serovars are those strains that have antigenic properties that differ from other strains....
s:
trachomaTrachoma is an infectious eye disease, and the leading cause of the world's infectious blindness. Globally, 84 million people suffer from active infection and nearly 8 million people are visually impaired as a result of this disease...
(serovars A, B, Ba or C),
urethritisUrethritis is inflammation of the urethra. The main symptom is dysuria, which is painful or difficult urination.-Diagnosis:Usually, the patient undresses and puts on a gown. The physician examines the penis and testicles for soreness or any swelling...
(
serovarA serovar or serotype is a group of microorganisms or viruses classified together based on their cell surface antigens. Serovars allow the epidemiologic classification of organisms to the sub-species level...
s D-K), and
lymphogranuloma venereumLymphogranuloma venereum is a sexually transmitted disease caused by the invasive serovars L1, L2, or L3 of Chlamydia trachomatis.LGV was first described by Wallace in 1833 and again by Durand, Nicolas, and...
(LGV, serovars L1, 2 and 3).
Chlamydia trachomatis, an
obligate intracellularIntracellular parasites are parasitic microorganisms that are capable of growing and reproducing inside the cells of a host.-Facultative:Facultative intracellular parasites are capable of living reproducing inside or outside cells....
human pathogen, is one of three
bacteriaThe bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
l species in the
genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
ChlamydiaChlamydia refers to a genus of bacteria that are obligate intracellular parasites . Many of the chlamydia species are pathogenic....
.
C. trachomatis is Gram-indeterminate (i.e. cannot be stained with the
Gram stainGram staining is an empirical method of differentiating bacterial species into two large groups based on the chemical and physical properties of their cell walls...
); structurally the organism is
Gram-negativeGram-negative bacteria are those bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
. Identified in 1907,
C. trachomatis was the first chlamydial agent discovered in humans.
C. trachomatis includes three human
biovarA biovar is a variant prokaryotic strain that differs physiologically and/or biochemically from other strains in a particular species. Morphovars are those strains that differ physiologically. Serovars are those strains that have antigenic properties that differ from other strains....
s:
trachomaTrachoma is an infectious eye disease, and the leading cause of the world's infectious blindness. Globally, 84 million people suffer from active infection and nearly 8 million people are visually impaired as a result of this disease...
(serovars A, B, Ba or C),
urethritisUrethritis is inflammation of the urethra. The main symptom is dysuria, which is painful or difficult urination.-Diagnosis:Usually, the patient undresses and puts on a gown. The physician examines the penis and testicles for soreness or any swelling...
(
serovarA serovar or serotype is a group of microorganisms or viruses classified together based on their cell surface antigens. Serovars allow the epidemiologic classification of organisms to the sub-species level...
s D-K), and
lymphogranuloma venereumLymphogranuloma venereum is a sexually transmitted disease caused by the invasive serovars L1, L2, or L3 of Chlamydia trachomatis.LGV was first described by Wallace in 1833 and again by Durand, Nicolas, and...
(LGV, serovars L1, 2 and 3). Many, but not all,
C. trachomatis strains have an extrachromosomal
plasmidA plasmid is an extra-chromosomal DNA molecule separate from the chromosomal DNA which is capable of replicating independently of the chromosomal DNA. In many cases, it is circular and double-stranded...
.
Identification
Chlamydia species are readily identified and distinguished from other chlamydial species using DNA-based tests.
Most strains of
C. trachomatis are recognized by
monoclonal antibodiesMonoclonal antibodies are monospecific antibodies that are identical because they are produced by one type of immune cell that are all clones of a single parent cell. Given almost any substance, it is possible to create monoclonal antibodies that specifically bind to that substance; they can then...
(mAbs) to epitopes in the VS4 region of MOMP. However, these mAbs may also cross-react with two other
Chlamydia species,
C. suisChlamydia suis is a member of the genus Chlamydia. C. suis has only been isolated from swine, in which it may be endemic. Glycogen has been detected in Chlamydia suis inclusions in infected swine tissues and in cell culture. C...
and
C. muridarumChlamydia muridarum is an intracellular bacterial species that at one time belonged to Chlamydia trachomatis. However, C. trachomatis naturally only infects humans and C...
.
Clinical significance
C. trachomatis is a obligate intracellular pathogen (i.e. the bacterium lives within human cells) and can cause numerous disease states in both men and women. Both sexes can display
urethritisUrethritis is inflammation of the urethra. The main symptom is dysuria, which is painful or difficult urination.-Diagnosis:Usually, the patient undresses and puts on a gown. The physician examines the penis and testicles for soreness or any swelling...
,
proctitisProctitis is an inflammation of the anus and the lining of the rectum, affecting only the last 6 inches of the rectum.-Overview:Symptoms are ineffectual straining to empty the bowels, diarrhoea, rectal bleeding and possible discharge, a feeling of not having adequately emptied the bowels,...
(rectal disease and bleeding),
trachomaTrachoma is an infectious eye disease, and the leading cause of the world's infectious blindness. Globally, 84 million people suffer from active infection and nearly 8 million people are visually impaired as a result of this disease...
, and
infertilityInfertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...
. The bacterium can cause
prostatitisProstatitis is an inflammation of the prostate gland, in men. A prostatitis diagnosis is assigned at 8% of all urologist and 1% of all primary care physician visits in the United States.-Classification:...
and
epididymitisEpididymitis is a medical condition in which there is inflammation of the epididymis . This condition may be mildly to very painful, and the scrotum may become red, warm and swollen...
in men. In women,
cervicitisInflammation of the tissues of the cervix is known as cervicitis. Cervicitis in women has many features in common with urethritis in men and many of the causes are sexually transmitted.-Causes:...
,
pelvic inflammatory diseasePelvic inflammatory disease is a generic term for inflammation of the female uterus, fallopian tubes, and/or ovaries as it progresses to scar formation with adhesions to nearby tissues and organs. This may lead to tissue necrosis and sometimes abscess formation whereby pus can be released into...
(PID),
ectopic pregnancyAn ectopic pregnancy is a complication of pregnancy in which the fertilized ovum is developed in any tissue other than the uterine wall. Most ectopic pregnancies occur in the Fallopian tube , but implantation can also occur in the cervix, ovaries, and abdomen...
, and acute or chronic pelvic pain are frequent complications.
C. trachomatis is also an important neonatal pathogen, where it can lead to infections of the eye (
trachomaTrachoma is an infectious eye disease, and the leading cause of the world's infectious blindness. Globally, 84 million people suffer from active infection and nearly 8 million people are visually impaired as a result of this disease...
) and pulmonary complications.
Treatment
C. trachomatis may be treated with any of several antibiotics:
azithromycinAzithromycin is an azalide, a subclass of macrolide antibiotics.Azithromycin is one of the world's best-selling antibiotics, and is derived from erythromycin; however, it differs chemically from erythromycin in that a methyl-substituted nitrogen atom is incorporated into the lactone ring, thus...
,
erythromycinErythromycin is a macrolide antibiotic that has an antimicrobial spectrum similar to or slightly wider than that of penicillin, and is often used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma and...
or
doxycyclineDoxycycline is a member of the tetracycline antibiotics group and is commonly used to treat a variety of infections. Doxycycline is a semi-synthetic tetracycline invented and clinically developed in the early 1960s by Pfizer Inc. and marketed under the brand name Vibramycin. Vibramycin received...
/
tetracyclineTetracycline is a broad-spectrum polyketide antibiotic produced by the Streptomyces genus of Actinobacteria, indicated for use against many bacterial infections. It is a protein synthesis inhibitor. It is commonly used to treat acne today, and more recently, rosacea, and played a historical role...
.,cefpodoxim proxetil,amoxicillin
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