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PubMed2005

Real-time PCR for pharmacodynamic studies of Chlamydia trachomatis.

Pharmacodynamic knowledge about Chlamydia trachomatis exposed to antibiotics is hampered due to methodological limitations. We have developed a quantitative real-time PCR method (qRT-PCR) for determination of viable C. trachomatis. The method measures specific RNA transcripts of omp2 (omcB) as an expression of viable C. trachomatis. Two clinical isolates (one strain derived from a patient with recurrent symptoms despite doxycycline treatment) were cultured in McCoy cells and exposed to doxycycline at concentrations of 0.0078-64 mg/L. MIC values were evaluated microscopically by immunofluorescence (IF) and by qRT-PCR performed on cDNA prepared from the total RNA. The MIC for two C. trachomatis strains were determined to 0.016 and 0.031 mg/L by both qRT-PCR and IF. The qRT-PCR assay enabled MIC determinations without subjective evaluation, which is a problem when visually evaluating inclusions. The presented qRT-PCR is a suitable method for MIC determination of C. trachomatis. It has the advantage of giving quantitative measurements of chlamydial RNA levels and the method is useful in pharmacodynamic studies of C. trachomatis.

Anti-Bacterial Agents↗

PubMed2003

Inhibition of host cell cytokinesis by Chlamydia trachomatis infection.

UNLABELLED: OBJECTIVES. Chlamydia has to replicate in cytoplasmic vacuoles of eukaryotic cells. To understand how chlamydia interacts with host cells during cell division, we examined the effect of chlamydial infection on host cell cycle. METHODS: An immunofluorescence microscopic approach was used. RESULTS: Although the number of cells was significantly reduced in chlamydia-infected cultures, multiple nuclei were detected in the infected cells, indicating that chlamydia inhibited host cell growth by selectively blocking cytokinesis while allowing mitosis to proceed. The chlamydial inhibition of host cell cytokinesis was confirmed with various strains of Chlamydia trachomatis and in several types of host cells. Furthermore, the chlamydial inhibitory effect was found to depend on chlamydial protein synthesis. DISCUSSIONS: These observations suggest that chlamydia may have evolved specific mechanisms for actively blocking host cell cytokinesis.

Animals↗

PubMedDate not supplied

Examination of men with nongonococcal urethritis and their sexual partners for Chlamydia trachomatis and Ureaplasma urealyticum.

Chlamydia trachomatis was recovered from 39 (52%) of 75 men who had nongonococcal urethritis and from 28 (37%) of their sexual partners. Of the partners of men with Chlamydia-positive nongonococcal urethritis, 64% excreted Chlamydia, compared with 8% of the partners of men with Chlamydia-negative nongonococcal urethritis. In contrast, an apparently sexual mode of transmission was not observed with Ureaplasma urealyticum. Rates of recovery of U. urealyticum from men with nongonococcal urethritis whose cultures were Chlamydia-positive and those whose cultures were Chlamydia-negative were the same. Significant seroconversion was detected bythe single-antigen immunofluorescence test in about 50% of patients who had Chlamydia-postive cultures.

Adult↗

PubMed1988

Chlamydia trachomatis genital infections in Tahiti.

The rate of Chlamydia trachomatis infection was determined in three populations in Tahiti by means of a direct immunofluorescence test performed in specimens, tissue culture and detection of chlamydial antibody in serum specimens using a single-serotype indirect immunofluorescence test. Chlamydia trachomatis was recovered in 53% of 53 bar girls, 24% of 75 women attending a public maternity clinic for routine care, and 37% of 71 men attending a sexually transmitted disease clinic with acute or subacute urethritis. The presence of chlamydial antibody in a high proportion of the groups studied confirmed the high frequency of chlamydial infections (62.3%, 66.6% and 83.1% respectively). Neisseria gonorrhoeae infection was often associated with chlamydial infection in both bar girls and men with urethritis (11.4% and 18.3% respectively). With regard to clinical manifestations, 58.3% (7/12) of bar girls and 23.2% (10/43) women at the maternity clinic without clinical complaints were found to be Chlamydia trachomatis-positive. The presence of Chlamydia trachomatis in these asymptomatic persons highlights their important role in spread of this organism in Tahiti. The findings indicate that routine testing for Chlamydia trachomatis is warranted in patients attending the sexually transmitted disease and public maternity clinics in Tahiti.

Adolescent↗

PubMed1990

In vitro synergy of clindamycin and aminoglycosides against Chlamydia trachomatis.

The importance of Chlamydia trachomatis as an etiologic agent in the development of pelvic inflammatory disease (PID) is well documented. Although there are numerous antimicrobial agents that are effective against C. trachomatis, one of the most frequent combinations that is used to treat PID is clindamycin and gentamicin. The efficacy of clindamycin as the sole treatment for chlamydial infections has been questioned. In fact, the Centers for Disease Control (Atlanta, Ga.) has recommended the use of doxycycline following clindamycin and gentamicin treatment of PID confirmed or suspected to be caused by C. trachomatis. This study was designed to determine whether there is any synergistic in vitro activity between clindamycin and gentamicin or tobramycin on inhibition of C. trachomatis replication. In this experiment, the MIC of clindamycin decreased two- to threefold when an aminoglycoside was added. This occurred even though aminoglycosides by themselves had essentially no effect against C. trachomatis. The mechanism of this interaction is uncertain.

Anti-Bacterial Agents↗

PubMed1996

Identification of sequences necessary for transcription in vitro from the Chlamydia trachomatis rRNA P1 promoter.

Chlamydia trachomatis RNA polymerase was partially purified by heparin-agarose chromatography and used in conjunction with a plasmid-borne G-less cassette template to characterize the C. trachomatis rRNA P1 promoter in vitro. Stepwise mutational analysis revealed that sequences in the -10, -25, and -35 regions are necessary for promoter activity, but no sequence upstream of position -40 is required. Partially purified C. trachomatis RNA polymerase and purified Escherichia coli holoenzyme exhibited some differences in promoter specificity.

Base Composition↗

PubMedDate not supplied

Experimental infection of the chimpanzee urethra and pharynx with Chlamydia trachomatis.

An isolate of Chlamydia trachomatis obtained from a man with nongonococcal urethritis was used to produce experimental urethral and pharyngeal infections in chimpanzees. After urethral inoculation of 8 X 10(1) inclusion-forming units (IFU), infections were established in three of three animals; urethral discharges developed in two. The infections persisted for five to nine weeks. Larger inocular (7 X 10(2) and 1 X 10(5) IFU) produced pharyngeal infections in two animals. The third animal's pharynx was not infected by 1 X 10(5) IFU. Chlamydial complement-fixing antibodies increased significantly in sera of two of three animals. This study provides an animal model for study of mucosal infection by C. trachomatis. The relative resistance of the chimpanzee pharynx to infection parallels clinical observations in man.

Animals↗

PubMed1986

Polyclonal response of human lymphocytes to Chlamydia trachomatis.

The mitogenicity of Chlamydia trachomatis was investigated. Umbilical cord blood cells from healthy newborns were used. These cells were stimulated in cultures with partially purified C. trachomatis elementary bodies. Proliferation of cultured lymphocytes and secreted immunoglobulins and leukocyte migration inhibitory factor were measured in the culture supernatants. Our results showed that C. trachomatis is able to elicit polyclonal antibody, lymphokine, and DNA synthesis.

Antibodies, Bacterial↗

PubMed2005

Interleukin (IL)-2 and IL-12 responses to Chlamydia trachomatis infection in adolescents.

Chlamydia trachomatis infects epithelial cells at the mucosal surface. While in vitro and animal studies have shown changes in mucosal T(H)1-associated cytokines in the presence of C. trachomatis infection and with its progression to the upper genital tract or clearance, in vivo cytokine responses to chlamydial infection in humans are not well understood. Using a quantitative enzyme-linked immunosorbent assay (ELISA), we examined the endocervical production of two T(H)1-associated cytokines, i.e. interleukin (IL)-2 and IL-12, in relation to C. trachomatis infection in adolescents. At a randomly selected visit for 396 females, median endocervical IL-2 levels were significantly lower (190 versus 283 pg/ml, P = 0.02) and median IL-12 levels significantly higher (307 versus 132 pg/ml, P < 0.001) in subjects testing positive versus negative for C. trachomatis. These divergent T(H)1-associated cytokine responses were: (1) confirmed in paired analyses of 96 individuals before and after infection within 6-month intervals, (2) reversible in 97 patients who cleared infection during consecutive visits, (3) not attributable to sociodemographic factors or other genital infections and (4) independent of common genetic variants at the IL2 and IL12B loci associated previously with differential gene expression. From these findings we infer that increased IL-12 and decreased IL-2, observed commonly during mucosal inflammation, are important features of mucosal immune defence against C. trachomatis infection.

Adolescent↗

PubMed1995

Screening for Chlamydia trachomatis infection.

Infection with Chlamydia trachomatis can be either symptomatic or asymptomatic. In adults, complications include infertility, chronic pelvic pain and ectopic pregnancy. Complications in newborns include conjunctivitis and pneumonia. Screening of asymptomatic women at high risk for the disease can identify candidates for antibiotic therapy. Until recently, chlamydia cell culture was the only diagnostic test and it was not widely available. Because the specificity of cell culture is 100 percent, it remains the standard against which other tests are measured. The recent development of nonculture tests makes it feasible for most laboratories and physicians' offices to offer testing. The main disadvantage of nonculture tests is low specificity. A positive screening test in a woman at low risk should be confirmed by a second test. Routine screening and treatment of patients who are at high risk can decrease the incidence, complications and transmission of chlamydial infection.

Chlamydia Infections↗

PubMed2003

[Hela cells secrete interleukin-8 and interleukin-10 response to Chlamydia trachomatis entry].

OBJECTIVE: To investigate the effect of Chlamydia trachomatis serotype K infection on productions of IL-8 and IL-10 in supernatant of cultured Hela cells. METHODS: The levels of IL-8 and IL-10 productions were detected by cell culture method and ELISA assay. RESULTS: The amount of IL-8 and IL-10 in the cell culture supernatant rose with the increasing doses of Chlamydia trachomatis. The concentrations of IL-8 and IL-10 began to increase obviously at 24 h, and reached their highest level at 72 h, and then decreased. Heat-inactivated Chlamydia trachomatis induced lower levels of IL-8 and IL-10 production than live bacteria in vitro. CONCLUSION: The Chlamydia trachomatis can induce the secretion of IL-8 and IL-10 of host cells in a dose and time dependent manner and the intracellar replication of the bacteria is required for enhancing IL-8 and IL-10 productions by the infected cells.

Chlamydia trachomatis↗

PubMed1993

DNA sequence polymorphism of the Chlamydia trachomatis omp1 gene.

The Chlamydia trachomatis major outer membrane protein gene (omp1) was amplified by polymerase chain reaction (PCR) from 89 clinical specimens, and restriction fragment length polymorphism (RFLP) patterns were analyzed after AluI or AluI and MspI digestion. Ten distinct RFLP omp1 genotypes were observed, although 4 types accounted for 70% of the isolates. The DNA sequence of variable domains (VDs) 1, 2, and 4 were determined for 49 samples. Thirty samples (61%) had prototype VD sequences, 15 (31%) had sequences that varied from prototype sequences, and 4 (8%) contained sequences from > 1 chlamydial isolates. Eleven of the 15 DNA sequence variations were one- or two-site nucleotide substitutions, 10 of which resulted in an amino acid change. Four DNA sequence variations were more extensive, with multiple nucleotide substitutions, insertions, or deletions. The data demonstrate that C. trachomatis isolates circulating in a relatively circumscribed geographic community exhibit remarkable omp1 DNA sequence polymorphism.

Amino Acid Sequence↗

PubMed1986

Salpingitis in mice induced by human strains of Chlamydia trachomatis.

Human strains of Chlamydia trachomatis were inoculated unilaterally into the genital tracts of female TO, CBA, CBA/nu and C3H mice via the intrauterine route or under the ovarian bursa. Inflammatory changes were not seen in the oviducts or uterus of mice given two laboratory-adapted LGV serovars (L1 and L2), although chlamydiae were recovered from the lower genital tract. However, salpingitis and endometritis occurred after each of three chlamydial strains (serovars D and E) had been inoculated. Oviduct inflammation was seen for up to 6 weeks after inoculation but reached maximum severity usually after about 2 weeks, the lumen sometimes being occluded by exudate and necrotic debris. Pathological changes were seen often in both oviducts indicating canalicular spread of the organisms through the uterus. Pre-treatment of the mice with progesterone had an enhancing effect in that the lesions developed more rapidly; such treatment, in halting the oestrous cycle, probably made a larger number of target cells available for more efficient infection. Involvement of the oviduct on the uninoculated side occurred more rapidly in T-cell impaired nude mice than in immunologically normal mice, although there was little or no effect on the severity of the oviductal changes. There was evidence that the susceptibility of different strains of mice to chlamydial salpingitis varied. Thus, inflammatory changes in C3H mice were more severe than in TO mice and the changes in C3H and CBA strains were longer lasting than those in TO mice. This suggests that a possible genetic predisposition in the human situation should not be ignored. Finally, one chlamydial strain of low passage produced more severe salpingitis in mice than another strain of similar passage. By analogy different chlamydial strains may not be of equal pathogenicity in the human situation.

Animals↗

PubMed1993

Diversity in the Chlamydia trachomatis histone homologue Hc2.

Chlamydia trachomatis elementary bodies contain two developmentally expressed histone H1 homologues. An 18-kDa histone homologue, Hc1, is conserved among C. trachomatis serovars and C. psittaci. The other histone homologue, Hc2 (encoded by hctB), varies in size between C. trachomatis serovars but is present in reduced amounts or absent from C. psittaci. The variation in Hc2 size among C. trachomatis serovars was found to be due to internal deletions from a region of the hctB gene encoding lysine- and alanine-rich pentameric repeats.

Amino Acid Sequence↗

PubMed1991

Chlamydia trachomatis: female pelvic infection.

Chlamydia trachomatis is a bacterium that causes both symptomatic and asymptomatic infection. This infection has been associated with severe infections of the upper genital tract, such as salpingitis, which may be responsible for a significant number of cases of ectopic pregnancy and infertility. An unsettled question is the role of C. trachomatis in pregnant patients. In addition to causing cervicitis, it has been linked to chorioamnionitis, premature rupture of membranes, and premature delivery. However, chlamydial infection is an easily treatable disease. The main focus of prevention is appropriate prescreening of patients at risk.

Chlamydia Infections↗

PubMed1985

Chlamydia trachomatis infection in women.

Chlamydia trachomatis is found worldwide and is probably the most common sexually transmitted disease, infecting both females and males, adults as well as children. The organism is responsible for a variety of infections in women--urethral syndrome, cervicitis, endometritis and salpingitis. C. trachomatis may colonize the lower genital tract and result in asymptomatic infection, ultimately resulting in sterility. In addition, infection of the female genital tract during pregnancy may result in spontaneous abortion, premature labor, postpartum endometritis, neonatal conjunctivitis or pneumonia.

Acute Disease↗

PubMed1980

A case of lymphogranuloma venereum of 20 years' duration. Isolation of Chlamydia trachomatis from perianal lesions.

Chlamydia trachomatis was isolated from perianal lesions in a patient in whom lymphogranuloma venereum had been diagnosed 20 years previously. Treatment with tetracycline resulted in a pronounced improvement. Although C trachomatis is known to persist for a long time in the host, isolation of the micro-organism from infected tissues after such a prolonged period has not previously been reported.

Aged↗

PubMed1988

[The importance of tetracycline treatment of cervical Chlamydia trachomatis infections: control with cervical smears].

Cervical Chlamydia trachomatis infection is extremely common, crucial and sexually transmitted disease. In order to prevent from this disease an effective treatment is necessary. Tetracycline is an effective antimicrobial medicine for treatment of cervical Chlamydia trachomatis infection. In our study, after we had established the diagnosis of Chlamydia trachomatis on the patient's cervical smear, Tetracycline was used for treatment. In control smear after treatment. Chlamydial intracytoplasmic inclusion bodies and atypical cellular changes which we observed in the first smear were not seen.

Chlamydia Infections↗