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At least 19 recordsLinked to original sources
PubMed1979

[The replication cycle of Chlamydia trachomatis and Chlamydia psittaci: ultrastructural analysis].

An ultrastructural comparative analysis is reported on the replication cycle of six strains of Chlamydia trachomatis, recently isolated, and Chlamydia psittaci strain 6BC, grown in cell cultures. Important morphological distinctions of the bacterial walls are documented. In Chlamydia trachomatis the cell wall seems more rigid. This causes, during the morphogenesis of the elementary body, its separation from the cell membrane with formation of an electron transparent space, which is not demonstrable in Chlamydia psittaci. As a result of this process, the appearance of "ghosts" and "mini reticular bodies" is documented. Budding and multiple fission are suggested as possible mechanisms of replication of Chlamydia trachomatis, in coexistence or/as alternative to binary fission.

Cell Wall↗
PubMed2025

A platform supporting generation and isolation of random transposon mutants in Chlamydia trachomatis.

Chlamydia species represent a paradigm for understanding successful obligate intracellular parasitism. Despite limited genetic malleability, development of genetic tools has facilitated the elucidation of molecular mechanisms governing infectivity. Random mutagenesis approaches provide one of the most powerful strategies available to accomplish untargeted elucidation of gene function. Unfortunately, initial progress in transposon-mediated mutagenesis of Chlamydia has been challenging. To increase efficiency, we developed a plasmid-based system that couples conditional plasmid maintenance with a previously described strategy leveraging inducible expression of the Himar1-derived C9 transposase. Our pOri-Tn(Q) construct was maintained in Chlamydia trachomatis cultivated with antibiotics but was rapidly cured in the absence of antibiotic selection. pOri-Tn(Q) supported transposition events when transposase expression was induced during infection. Induction was accompanied by loss of the plasmid backbone when penicillin G was used to select for only the transposable element. C9 induction during iterative passaging was used to increase the overall insertion frequency and accumulate an expanded pool of transposon mutants. The approach supported isolation of individual mutant strains from the mixed pool, and whole-genome sequencing confirmed that the recovered strains harbored single insertions.IMPORTANCEChlamydia trachomatis is a prevalent human pathogen exerting a tremendous negative impact on human health. A complete understanding of how these bacteria create and maintain an intracellular niche and avoid/subvert host defense mechanisms to cause disease is lacking. The utility of transposon-mediated, random mutagenesis in supporting forward genetic studies is well established in a multitude of genetically tractable systems. This study reports the development of a plasmid-based system capable of generating mutant pools and supporting subsequent isolation of individual transposon mutants. This step is an important advance in providing a mechanism capable of supporting downstream studies interrogating chlamydial biology.

Chlamydia trachomatis↗
PubMed1979

Experimental acute salpingitis in grivet monkeys provoked by Chlamydia trachomatis.

Chlamydia trachomatis is a common cause of sexually transmitted diseases. Recently it has been shown that chlamydiae are also responsible for complications to such lower genital tract infections. In this study, isolates of C. trachomatis from the fallopian tubes of patients with acute salpingitis were inoculated direct into the fallopian tubes of two, and through the cervical canal into the uterine cavity of one grivet monkey. The experimental infections resulted in a self-limited acute salpingitis in the three animals. C. trachomatis was recovered from the monkeys 2 and 3 weeks post inoculation. As found at laparotomy, the infected tubes were swollen and reddened, and there was watery exudate in the abdominal ostia. Microscopically, cellular infiltrates--mainly lymphocytes--were seen in the mucosa, muscularis and subserosa of the tubes. Serologically, a primary antibody response with an IgM to IgG conversion was found. Salpingitis did not occur in a control monkey inoculated in the tubes with a medium lacking Chlamydia. The histological changes in the fallopian tubes of the infected monkeys were reminiscent of those described as being characteristic of "gonococcal" salpingitis in man. The fulfilment of Koch's postulates in the animal model used adds to the earlier evidence that C. trachomatis is capable of causing acute salpingitis in humans.

Acute Disease↗
PubMed1978

Prediction of efficacy of antimicrobial agents in treatment of infections due to Chlamydia trachomatis.

Although Chlamydia trachomatis is readily eradicated by systemic therapy in patients with acute urethritis, systemic therapy is less satisfactory in treatment of chronic trachoma. The activities of antimicrobial agents against C. trachomatis in cell cultures when the antimicrobial agents are added 1 hr after the C. trachomatis (minimal inhibitory concentration [MIC]) predicts efficacy of the drugs in the treatment of urethritis but does not necessarily predict efficacy in the treatment of chronic ocular trachoma. Concentrations of antimicrobial agents required to eradicate C. trachomatis when the agents were added 48 hr after inoculation of the cell cultures with C. trachomatis exceeded the MIC by several logarithms, and minocycline, doxycycline, and rifampin were markedly more active than tetracycline, erythromycin, or several other antimicrobial agents. Of the three most active antimicrobial agents, only doxycycline has been used systemically to treat ocular infections due to C. trachomatis, and it has been reported to be the most effective antimicrobial agent that has been utilized. In vitro testing of obligate intracellular pathogens such as C. trachomatis presents unique problems. Utilization of several methods of testing may help to identify antimicrobial agents with improved clinical efficacy, particularly in the treatment of ocular trachoma.

Anti-Bacterial Agents↗
PubMed1977

Respiratory-tract colonization and a distinctive pneumonia syndrome in infants infected with Chlamydia trachomatis.

To learn if Chlamydia trachomatis causes in young infants a distinctive penumonia characterized by chronic, afebrile course, diffuse lung involvement and elevated serum immunoglobulins G and M, 47 black infants four to 24 weeks of age were examined for nasopharyngeal shedding of C. trachomatis and serum immunofluorescent antibody to lymphogranuloma venereum Type I. Nasopharyngeal C. trachomatis was found in 18 of 20 with the pneumonia syndrome, two of 15 with various other illnesses and 10 of 12 with inclusion conjunctivitis but without lower respiratory illness. Chlamydial antibody titers of infants with the pneumonia syndrome were significantly elevated (geometric mean-1, pneumonia vs. conjunctivitis = 24,833 vs. 1024 P less than 0.001). No other commonly recognized respiratory pathogens were consistently associated with the pneumonia syndrome. We believe these findings demonstrate an association between the distinctive pneumonia syndrome and C. trachomatis. This, in turn, is a particular facet of a more general event consisting of frequent colonization of the respiratory tract by C. trachomatis in natally acquired infection.

Antibodies, Bacterial↗
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↗
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↗
PubMed1977

Etiology of nongonococcal urethritis. Evidence for Chlamydia trachomatis and Ureaplasma urealyticum.

Chlamydia trachomatis, Ureaplasma urealyticum (T-mycoplasma), and Hemophilus vaginalis have previously been considered possible etiological agents in nongonococcal urethritis (NGU). In this study, current C. trachomatis infection was confirmed by culture and (or) micro-immunofluorescence serology in 26 of 69 men experiencing afirst episode of NGU, and 1 of 39 with no urethritis. Serum IgM immunofluorescent antibody to chlamydia was demonstrated in 16 of 20 men with chlamydia culture positive NGU, and 3 of 39 with chlamydia culture negative NG, and none of 34 with no urethritis. 9 of 10 culture positive men with less than or equal to 10 days symptoms developed immunofluorescent antibody seroconversion in paired sera. U. realyticum was isolated significantly more often and in significantly higher concentration from first voided urine from chlamydia-negative cases of NGU than from chlamydia-positive NGU. Ureaplasmacidal antibody titers increased fourfold in six men, four of whom had negative cultures for for unreaplasma. H. vaginalis was isolated from c9 of 33 men with no urethritis and 2 of 69 with NGU. C. trachomatis is susceptible, and U. urealyticum is resistant to sulfonamides. A 10-day course of sulfisoxazole therapy produced improvement in 13 of 13 chlamydia-positive, unreaplasma-negative, and only 14 of 29 chlamydia-negative, unreaplasma-positive NGU cases (P less than 0.002). Thus, culture, serology, and response to therapy support the etiologic role of chlamydia in NGU. Quantitative culture and response to therapy suggest U. unrealyticum may cause many cases of chlamydia-netative NGU.

Adult↗
PubMed1979

Pneumonia associated with Chlamydia trachomatis infection in an infant.

Chlamydia trachomatis was isolated from the epipharynx of a 10-week-old baby girl taken ill with pneumonia but without signs of conjunctivitis. The infant developed specific antibodies to the organism. The course of the pneumonia was protracted, with cough and tachypnea. The baby, who was afebrile, improved on antibiotic therapy but pulmonary infiltrates persisted for several months. To our knowledge, this is the first case of pneumonia in an infant associated with C. trachomatis infection reported elsewhere than North America.

Chlamydia Infections↗
PubMed1977

Antibiotic susceptibility of Chlamydia trachomatis.

The antibiotic susceptibility of Chlamydia trachomatis isolates was determined in a tissue culture system. Representatives of all currently recognized serotypes of trachoma-inclusion conjunctivitis agents were tested. Tetracycline and erythromycin yielded similar results, with 1.0 mug/ml preventing chlamydial replication. Rifampin was the most active antibiotic, with 0.25 mug/ml completely suppressing inclusion formation of all strains. Fifty percent end points were usually achieved at one-fourth to one-eighth the 100% suppression level. Penicillin was not as effective, and the assays were often irregular. Antibiotic susceptibility of these chlamydiae was essentially the same, regardless of serotype, anatomic site infected, geographic origin, or antibiotic use in the community.

Chlamydia trachomatis↗
PubMed1977

Chlamydia trachomatis infection and veneral disease.

Chlamydia trachomatis was isolated by the irradiated McCoy cell technique from 44 out of 103 men with non-gonorrhoeic urethritis and from 11 out of 15 patients with post-gonococcal urethritis. In women attending the venereal diseases clinics, chlamydial infection was observed in 49 out of 130 patients (38%), an infection incidence of the same order of magnitude as the one noted for gonococcal infection (40%). In 19% both infections occurred simultaneously. Treatment with tetracycline eliminated symptoms and chlamydial infection in almost all cases. The significance of the findings is discussed.

Anti-Bacterial Agents↗
PubMed1977

Isolation of Chlamydia trachomatis from the male urethra.

Chlamydia trachomatis was isolated from 26% of urethral swabs taken from 509 men with urethritis. The highest yield of 68% was obtained from a selected group of men with nonspecific urethritis (NSU) who had a frank urethral discharge. This is a higher than in previous reports, and is significantly higher than the isolation of C. trachomatis from men with less severe urethritis. The higher yield was similar to C. trachomatis isolation rates reported among patients with severe trachoma in hyperendemic areas. Men with a previous history of NSU had low isolation rates. Overall, 30% of 385 men with NSU had positive chlamydial culture results, 7% of 59 men with gonococcal urethritis alone were Chlamydia-positive, 15% of 59 men with gonorrhoea followed by NSU (post-gonococcal urethritis) were Chlamydia-positive, and only 3% of 61 men without urethritis harboured Chlamydia. Swabs taken from the cervical os of 28 of 108 female contacts of men with NSU had a positive result for C. trachomatis. Significantly more pairs of sexual partners had the same chlamydial culture result than had different results. The chlamydial isolation rate was higher among men admitting a casual sexual contact than in men claiming only regular partnerships. The findings provide further evidence for the sexual transmission of C. trachomatis and for its aetiological role in NSU.

Chlamydia Infections↗
PubMed1979

[Antibodies against Chlamydia trachomatis in patients with non-gonococcal urethritis and in the healthy Italian population].

The Authors report the results of a study on the prevalence of serum antibodies against Chlamydia trachomatis among patients with non-gonococcal urethritis caused by Chlamydia trachomatis and diagnosed on the basis of the isolation of the microorganism in cell cultures, among patients with non-gonococcal urethritis of unknown etiology and in groups of healthy population, in Italy. The search for antibodies was performed both with complement-fixation tests in micro-titer system, using an antigen prepared from chicken embryo yolk sacs infected with the 6BC strain of Chlamydia psittaci, and with indirect immunofluorescence tests. The indirect immunofluorescence tests were carried out using as antigen the whole chlamydial inclusion developed in IUDR pre-treated McCoy cell cultures, grown on coverslips, and infected with the BU/434 strain of the LGV2 immunotype of Chlamydia trachomatis. The immunofluorescence tests proved to be much more sensitive than the complement fixation tests in detecting the presence of anti-chlamydial antibody both in patients with non-gonococcal urethritis and in the healthy population groups. The percentage of subjects possessing anti-chlamydial antibodies among the healthy population suggests a diffuse circulation of Chlamydia trachomatis infection. The possibility of employing the serological data in the diagnosis of the etiology of non-gonococcal urethritis is briefly discussed.

Adolescent↗
PubMed1978

Chlamydia trachomatis in gonococcal and postgonococcal urethritis.

Chlamydia trachomatis was isolated from the urethra of 38 (28.6%) out of 133 men with gonococcal urethritis (GU). During the follow up of 72 men postgonococcal urethritis (PGU) was diagnosed in 50 (69.5%) patients. More than half (30 out of 50) of these patients with PGU were Chlamydia-positive. Out of 31 patients with Chlamydia 30 developed PGU whether or not procaine penicillin, spectinomycin, or gentamicin were used. These findings are discussed in relation to present recommendations for the treatment and follow up of patients with GU.

Adult↗
PubMed1976

Isolation of Chlamydia trachomatis from women attending a clinic for sexually transmitted diseases.

Attempts were made to isolate Chlamydia trachomatis from the cervix of 300 women attending a clinic for sexually transmitted diseases in Leeds. The women were divided into four groups; (1) 130 were consorts of men suffering from non-specific urethritis; (2) 66 were suffering from gonorrhoea, or were consorts of men suffering from this disease; (3) 56 were suffering from other sexually transmitted diseases; (4) 48 had no evidence of STD. The overall isolation rate of Chlamydia trachomatis was 20%. Positive results were obtained in 30%. of Group 1, in 27-3%. of Group 2, in 3-6%. of Group 3, and in 2-1%. of Group 4. No pathogenic sign or symptom of Chlamydia trachomatis infection of the cervix was detected.

Adolescent↗
PubMed1978

Chlamydia trachomatis in non-specific urethritis.

Chlamydia trachomatis was isolated from 58.5% of 159 patients with non-specific urethritis (NSU) using irradiated McCoy cell cultures. Patients with persistent Chlamydia-positive NSU remained Chlamydia-positive each time they were examined before treatment and patients with Chlamydia-negative NSU remained Chlamydia-negative during the course of the illness. Neither the duration of symptoms of urethritis nor a history of previous urethritis affected the chlamydial isolation rate significantly. Of 40 patients with severe discharge 30 (75%) harboured C. trachomatis. One-third of the Chlamydia-positive patients had a severe urethral discharge, while this was present in only 15% of Chlamydia-negative patients. Complications--such as conjunctivitis, arthritis, and epididymitis--were more severe in men with Chlamdia-positive NSU than in those with Chlamydia-negative NSU. Of 64 men matched for sexual promiscuity but without urethritis, none harboured C. trachomatis in his urethra. This differs significantly (P less than 0.001) when compared with patients with NSU. C. trachomatis was isolated from the urogenital tract in 24 (42%) out of 57 female sexual contacts of patients with NSU. The presence of C. trachomatis in the women correlated significantly (P less than 0.001) with the isolation of the agent from their male contacts. These findings give further evidence for the aetiological role of C. trachomatis in non-specific urethritis and its sexual transmission.

Adult↗
PubMed1978

Separation and partial characterization of a type-specific antigen from Chlamydia trachomatis.

Type-specific antigens of Chlamydia trachomatis have been demonstrated by the mouse toxicity prevention test and a variety of immunofluorescent techniques. In addition, biologic activity has been associated with these antigens in terms of type-specific immunity to trachoma infections. This report is the first to describe the detection of a soluble type-specific antigen of C. trachomatis and its separation from those antigens that cross-react among different immunotypes. Test antigens were prepared by labeling the surface components of purified, yolk sac grown organisms with a radioiodinated intermediate (Bolton-Hunter reagent, 125I). The organisms were solubilized with Triton X-100 and gel filtered through Sepharose 6B. All fractions were then tested in radioimmunoassay for binding with rabbit antisera raised against solubilized immunogens prepared from homologous and heterologous strain organisms propagated in BHK-21 cells. A fraction demonstrating homologous binding only was used in subsequent modified procedures for the preparation of quantities of type-specific antigen sufficient for analysis. The antigen appears to be a heat labile, cell surface protein associated with apparent immunogenic activity during the course of actual chlamydial eye infection.

Antigen-Antibody Complex↗
PubMed1979

Isolation of Chlamydia trachomatis from eye secretion (tears).

Shedding of Chlamydia trachomatis in the eye secretion (tears) of patients with either hyperendemic trachoma or paratrachoma was studied. The method of collection of eye secretion with cellulose sponges is proved to be simple, faster, and more practicable and yielded a higher rate of chlamydial isolation than aspiration. The chlamydial isolation rates in eye secretion in chlamydia-positive paratrachoma patients in London or trachoma patients in Iran was 84 and 49% respectively. It was found that the chlamydial isolation rate from eye secretion is directly related to the number of inclusions present in the conjunctival swabbings. The results of this study indicated that patients with moderate to severe hyperendemic trachoma or paratrachoma are the main reservoir of infection. In the developing countries of the Middle East and Africa the shedding of chlamydia in the eye secretion of persons with these diseases is a major factor in the transmission of them by means of flies, fingers, towels, or bed clothes.

Chlamydia trachomatis↗