Immunity To Chlamydia Infections
The mouse model has extensively been used to analyze immune responses to C. muridarum primary and secondary genital infections . The results indicate that MHC-II restricted CD4+T-cells are necessary for protective immunity while MHC-I restricted CD8+T-cells do not appear to be essential for resolution of a primary infection, or a reinfection. The role of CD8+T-cells however is still controversial. For example, Johnson et al. have recently demonstrated that a Class II-restricted CD813 T-cell clone protected against a C. muridarum genital infection. Th1 cytokines, in particular IFN-, are needed to protect against C. muridarum. In contrast IL-10, a Th2 cytokine, is associated with pathological responses. Morrison and Morrison were the first to propose that an effective C. trachomatis vaccine may need to elicit tissue-resident memory cells in the genital tract.
Our understanding of the immune responses to a C. trachomatis infection in humans is quite limited. There is evidence that cellular immunity, with Th1 responses and IFN-y production, is needed to recover from infection and correlates with protection against reinfection . In humans, mucosal antibodies, especially IgA, show a relationship with reduced bacterial shedding . Darville et al. determined that in C. trachomatis infected women, serum and cervical IgG and IgA levels inversely correlated with cervical bacterial burden.
Chlamydia Trachomatis Vaccine Research Through The Years
Katelijn Schautteet
Abstract
Chlamydia trachomatis is a Gram-negative obligate intracellular bacterium. It is the leading cause of bacterial sexual transmitted infections . World Health Organization figures estimated that over 90 million new cases of genital C. trachomatis infections occur worldwide each year. A vaccination program is considered to be the best approach to reduce the prevalence of C. trachomatis infections, as it would be much cheaper and have a greater impact on controlling C. trachomatis infections worldwide rather than a screening program or treating infections with antibiotics. Currently, there are no vaccines available which effectively protect against a C. trachomatis genital infection despite the many efforts that have been made throughout the years. In this paper, the many attempts to develop a protective vaccine against a genital C. trachomatis infection will be reviewed.
1. Introduction
Chlamydia trachomatis is a Gram-negative obligate intracellular bacterium. It is the leading cause of bacterial sexually transmitted disease in both developed and developing countries with more than 90 million new cases of genital C. trachomatis infections occurring each year . In the past years, an increase in the number of STIs and in particular of C. trachomatis infections has been observed in many, if not all, European countries . This increase might be attributed to changes in attitudes, increased awareness of healthcare workers, and improved diagnostics.
How To Take It
Azithromycin is taken one time orally and can be taken with or without food. Its important to take it as directed by your doctor.
It takes approximately 1 week for azithromycin to cure chlamydia. Avoid having sex while under treatment, as its still possible to pass or worsen the infection during treatment.
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What You Need To Know About Azithromycin For Chlamydia Treatment
Chlamydia is one of the most common sexually transmitted diseases in America.
In fact, in 2018, four million infections occurred in the U.S. However, many cases may go unreported because people with chlamydia are often asymptomatic and therefore dont know they have an infection.
Because chlamydia can go undetected, regular testing is extremely important in both fighting the spread of the infection and in treating it.
If you happen to test positive, the good news is, the vast majority of chlamydia cases can be cured easily with antibiotics such as azithromycin.
In this article, Ill explain if azithromycin treats chlamydia, who can take this antibiotic, the best dosage to treat chlamydia, and how to take it.
Then Ill break down how azithromycin compares with another antibiotic, doxycycline, for treating chlamydia.
Finally, Ill share everything you need to know about being tested for chlamydia.
Is There A Chlamydia Vaccine
A vaccine is a treatment that sensitizes a persons body to a particular disease, helping protect against acquiring that specific disease in the future. It often takes years of research for new vaccine development.
For now, there is no vaccine for chlamydia however, there may be one in the coming years if further clinical trials show it to be safe and effective. In a recent issue of The Lancet Infectious Diseases, researchers reported that two versions of a chlamydia vaccine were found to be safe as part of a Phase 1 trial. Phase 1 human trials are done in very small groups of people and look at safety and side effects .
In this study, the potential vaccine candidates for chlamydia were deemed safe and well-tolerated, which means they could eventually move on to the next phase of clinical trials. Researchers also found that the chlamydia vaccines provoked an immune response against the STIwith no such response in the placebo group. The main side effect was a local reaction at the injection site. While these results are promising from a public health standpoint, more clinical trials are needed .
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Whats The Treatment For Chlamydia
Chlamydia is usually easy to get rid of. Your nurse or doctor will get you antibiotics to treat the infection. Sometimes you only have to take one dose of medication. Another chlamydia treatment lasts for 7 days. Your doctor will help you figure out which treatment is best for you.
If youre treated for chlamydia, its really important for your sexual partners to get treated also. Otherwise, you can keep passing the infection back and forth, or to other people. Sometimes your doctor will give you medicine for both you and your partner.
What Other Information Should I Know
Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body’s response to ceftriaxone injection.
Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking ceftriaxone injection.
If you are diabetic and test your urine for sugar, use Clinistix or TesTape to test your urine while taking this medication.
Ceftriaxone injection may interfere with certain home blood glucose tests. If you test your blood glucose levels, check the instructions of your blood glucose monitoring system to see if ceftriaxone injection will affect your system. You may need to use a different method to test your glucose levels while you are receiving ceftriaxone injection.
It is important for you to keep a written list of all of the prescription and nonprescription medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
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Can You Get Chlamydia More Than Once
Yes, you can get the infection even if youve successfully treated it already.
A sexual partner who has chlamydia can transmit it to you again, even if youve already had it and treated it.
You can also get chlamydia again if it wasnt fully treated the first time. This can happen if you stop taking the necessary treatment. Its important to complete the antibiotics youve been given, even if your symptoms get better.
The CDC recommends getting tested 3 months after treatment of your initial infection to ensure the infection is cleared.
Infant Pneumonia Caused By C Trachomatis
Chlamydial pneumonia among infants typically occurs at age 13 months and is a subacute pneumonia. Characteristic signs of chlamydial pneumonia among infants include a repetitive staccato cough with tachypnea and hyperinflation and bilateral diffuse infiltrates on a chest radiograph. In addition, peripheral eosinophilia occurs frequently. Because clinical presentations differ, all infants aged 13 months suspected of having pneumonia, especially those whose mothers have a history of, are at risk for , or suspected of having a chlamydial infection should be tested for C. trachomatis and treated if infected.
Diagnostic Considerations
Specimens for chlamydial testing should be collected from the nasopharynx. Tissue culture is the definitive standard diagnostic test for chlamydial pneumonia. Nonculture tests can be used. DFA is the only nonculture FDA-cleared test for detecting C. trachomatis from nasopharyngeal specimens however, DFA of nasopharyngeal specimens has a lower sensitivity and specificity than culture. NAATs are not cleared by FDA for detecting chlamydia from nasopharyngeal specimens, and clinical laboratories should verify the procedure according to CLIA regulations . Tracheal aspirates and lung biopsy specimens, if collected, should be tested for C. trachomatis.
Treatment
Erythromycin base or ethylsuccinate 50 mg/kg body weight/day orally divided into 4 doses daily for 14 days
Azithromycin suspension 20 mg/kg body weight/day orally, 1 dose daily for 3 days
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How Long Can You Have Chlamydia Without Knowing
Chlamydia is sometimes called a silent infection because the majority of people who have chlamydia regardless of gender never notice symptoms. People who do notice symptoms often dont recognize the signs that they have chlamydia until a few weeks after theyve been infected. Because chlamydia cases are often asymptomatic, its easy to spread chlamydia to someone else without realizing it. And its easy to miss out on receiving the treatment needed to prevent the serious complications that can result from chlamydia.
How Long Does It Take
It takes about one week for azithromycin to completely cure a chlamydial infection, and in some cases it can take up to two weeks for the infection to clear.
If you are sexually active during this time, you can pass the infection to your partner, even if you have no symptoms. For these reasons, you should avoid having sex of any kind during treatment.
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Animal Pathogenic Species With Zoonotic Potential
Other species of Chlamydia infect a wide range of animals leading to disease and reported zoonotic potential .
Chlamydia psittaci is a respiratory and reproductive pathogen of birds with zoonotic potential for humans. C. psittaci disease outbreaks in humans date back to 1879 where humans were infected from pet parrots and finches. In the 1930s, human pandemic outbreaks were linked to racing pigeons imported from South America to Europe and North America. More recently, human psittacosis outbreaks throughout Europe have been linked to turkey and duck farming . Broadly, a recent review and meta-analysis demonstrated that C. psittaci is the causative agent in 1% of worldwide community-acquired pneumonia .
Chlamydophila abortus predominantly infects the placenta of livestock resulting in fetal death and has the zoonotic potential to cause abortions in women if infected during pregnancy .
Mouse Model Vaccine Trials
Chlamydia muridarum is known to infect mice and rats causing conjunctivitis, respiratory disease and urogenital disease. The mouse model has been used as a host for vaccination trials because it is an amenable animal model, enabling post vaccination challenge experiments and detailed analysis of immune responses. The main purpose of studying chlamydial vaccines within the mouse model is for future development of a human chlamydial vaccine. Due to differences in the efficiency of certain strains within the mouse model, many studies chose to use C. muridarum as a surrogate for C. trachomatis.
The first MOMP-based vaccine in mice was by Tuffrey et al. . Using a recombinant MOMP from C. trachomatis serovar L1 and direct vaccination into the Peyers patches or oviducts, the trial failed to reduce colonization or disease development. However, humoral immune responses in plasma anti-MOMP IgG were detected along with trace levels of mucosal anti-MOMP IgA. This disappointing result was repeated in six additional protein-based vaccine trials over the next 20 years, with the only improvement being that the increases in plasma IgG responses had Chlamydia neutralizing effects . None of these seven trials used an adjuvant to stimulate immune responses during vaccination, generating a clear indication that an adjuvant-based vaccine would be required for a successful immunological response within a protein-based vaccine.
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Chlamydia Trachomatis: A Pathogen With A Complex Lifestyle
Chlamydia is caused by an infection with the bacterium C. trachomatis. Much like a virus, the bacterium relies totally on its host to survive and replicate. C. trachomatis has two developmental forms: a small non-replicating infectious form, which, after attachment, is internalised into the host cell and instantly reorganised into a metabolically active and a replicating form of almost triple the size. After completion of a replicative cycle, it reorganises into the infectious form again and is released from the host cell.
If the bacteria are not controlled by the immune system, they may ascend to infect the fallopian tubes and can cause major damage leading to pelvic inflammatory disease, scarring and occlusion.
Ophthalmia Neonatorum Caused By C Trachomatis
A chlamydial etiology should be considered for all infants aged 30 days who experience conjunctivitis, especially if the mother has a history of chlamydial infection. These infants should receive evaluation and age-appropriate care and treatment.
Preventing Ophthalmia Neonatorum Caused by C. trachomatis
Neonatal ocular prophylaxis with erythromycin, the only agent available in the United States for this purpose, is ineffective against chlamydial ophthalmia neonatorum . As an alternative, prevention efforts should focus on prenatal screening for C. trachomatis, including
Neonates born to mothers for whom prenatal chlamydia screening has been confirmed and the results are negative are not at high risk for infection.
Diagnostic Considerations
Treatment
Erythromycin base or ethylsuccinate 50 mg/kg body weight/day orally, divided into 4 doses daily for 14 days*
* An association between oral erythromycin and azithromycin and infantile hypertrophic pyloric stenosis has been reported among infants aged < 6 weeks. Infants treated with either of these antimicrobials should be followed for IHPS signs and symptoms.
Although data regarding use of azithromycin for treating neonatal chlamydial infection are limited, available data demonstrate that a short therapy course might be effective . Topical antibiotic therapy alone is inadequate for treating ophthalmia neonatorum caused by chlamydia and is unnecessary when systemic treatment is administered.
Follow-Up
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How Long Does Azithromycin Take To Cure Chlamydia
It usually takes approximately 7 days for azithromycin to cure chlamydia. However, it can take up to 2 weeks for the infection to go away completely.
Avoid having sex during treatment or until the infection has cleared. Youll want to make sure its completely cured, or else youll risk passing it to someone else.
Getting Treated For Chlamydia And Often Gonorrhea
If you have your own doctor, he will prescribe the antibiotics you need to treat chlamydia. If you dont have your own doctor, you can often find free or low-cost care at either a Planned Parenthood site or a community health clinic.
Listen carefully to the instructions for taking the medicine that you are given by the doctor or other healthcare provider, and follow them closely.
Ask questions if you dont understand something. Also, if you have other questions as you take your medicine, you can always call the pharmacist for help. They are often easier to reach than the doctor.
If you test positive for chlamydia, your healthcare provider is likely to also recommend that you be treated for gonorrhea. This is because the cost of treating gonorrhea is less than the cost of testing for the infection.
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How Common Is Chlamydia
Chlamydia is the most common STI caused by bacteria. Nearly 2 million cases of chlamydia were reported to the CDC in 2019. The number of infections is likely even higher. When compared to previous years, 2019 infection rates increased among people of all genders, all races and ethnicities, and in every region of the U.S. Most cases of chlamydia are asymptomatic, which means there are no signs or symptoms of an infection. Many of these cases likely go unreported.
Certain demographic characteristics may make you more likely to get diagnosed with chlamydia. Youre more likely to get diagnosed if youre:
- A teen or young adult aged 15 to 24. More than half of all diagnosed chlamydia cases in the U.S. occur in this age group.
- A cisgender woman aged 15 to 24. Young women in this age group are targeted for chlamydia screenings, and the rate of infection among those who are tested is high.
- A man who has sex with men . Chlamydia infections disproportionately affect men who have sex with men.
- Black and non-Hispanic. Chlamydia infections disproportionately affect non-Hispanic Black populations.
Complexity In Miniature The Chlamydia Trachomatis Lifecycle
The Ct chromosome encodes nearly 1000 proteins. Most isolates have a plasmid encoding 8 or 9 proteins which influence bacterial gene transcription. Ct has a bi-morphic life-cycle. The metabolically inactive, infectious, elementary bodies have an extensively cross-linked outer membrane which makes them very stable extracellularly. The main structural components are the major outer membrane protein , OmcA and OmcB. Other proteins are involved in tropism and attachment. Heinz et al used an in silico approach and Liu et al used proteomics to identify several outer membrane proteins which may be targets for intervention strategies.
Inside permissive cells, EBs transition into rapidly dividing reticulate bodies within host membrane bound inclusion bodies. Midway through the 48-72hr replication cycle some RBs transition to infectious EBs. The inclusion body expands and EBs are released by cell lysis or by extrusion of inclusion bodies. In vitro, persistent infection results from exposure to penicillin, IFN-, HSV infection and nutrient deprivation. Skilton et al demonstrated that penicillin removal from persistently infected cultures causes aberrant RBs to bud and form normal RBs which then complete replication. Whether persistent infection occurs in vivo remains uncertain.
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