Laboratory procedures for the isolation of chlamydia trachomatis from the human genital tract

Three-dimensional models of the cervicovaginal epithelia to study host-microbiome interactions and sexually transmitted infections

2D cell culture systems have historically provided controlled, reproducible means to analyze host-pathogen interactions observed in the human reproductive tract. Although inexpensive, straightforward, and requiring a very short time commitment, these models recapitulate neither the functionality of multilayered cell types nor the associated microbiome that occurs in a human. Animal models have commonly been used to recreate the complexity of human infections. However, extensive modifications of animal models are required to recreate interactions that resemble those in the human reproductive tract. 3D cell culture models have emerged as alternative means of reproducing vital elements of human infections at a fraction of the cost of animal models and on a scale that allows for replicative experiments. Here, we describe a new 3D model that utilizes transwells with epithelial cells seeded apically and a basolateral extracellular matrix (ECM)-like layer. The model produced tissues with morphologic and physiological resemblance to human cervical and vaginal epithelia, including mucus levels produced by cervical cells. Infection by Chlamydia trachomatis and Neisseria gonorrhoeae was demonstrated, as well as the growth of bacterial species observed in the human vaginal microbiota. This enabled controlled mechanistic analyses of the interactions between host cells, the vaginal microbiota, and STI pathogens. Affordable and semi high-throughput 3D models of the cervicovaginal epithelia that are physiologically relevant by sustaining vaginal bacterial colonization, and facilitate studies of chlamydial and gonococcal infections.

Shell Vial Culture assay for the rapid diagnosis of Japanese encephalitis, West Nile and Dengue-2 viral encephalitis

Background

Encephalitis caused by flaviviruses, Japanese encephalitis virus (JEV) and West Nile virus (WNV) is responsible for significant morbidity and mortality in many endemic countries. Dengue-2 (Den-2) virus is a recent addition to the list of encephalitogenic viruses, after its Central Nervous System (CNS) invasion capability has been established. There is a wide array of laboratory tools that have helped us not only in the diagnosis of these conditions but also in understanding their pathogenesis and pathology. However, there are no reports of Shell Vial Culture (SVC), a centrifuge enhanced tissue culture assay that has revolutionized viral culturing in terms of rapidity and sensitivity being optimized for these flaviviral encephalitic conditions. The present study is an attempt to standardize and evaluate the usefulness of SVC for the laboratory diagnosis of JE, WN and Den-2 encephalitis cases and to compare it with Indirect Immunofluorescence (IIF) technique that detects cell associated virus antigen. Analysis of the various clinical parameters with respect to viral etiology has also been carried out.

Results

Pediatric patients constituted the major group involved in the study (92%). Etiological diagnosis of viral encephalitis could be established in twenty nine (58%) patients. JE encephalitis was the commonest with 19 (39%) cases being positive followed by, WN (9 cases-18%) and Den-2 (one case). IIF test could detect antigens of JE, WN and Den-2 viruses in 16(32%), 7(14%) and 1 case respectively. Shell vial culture assay picked up all cases that were positive by IIF test. In addition, SVC assay could detect 3 and 2 more cases of JE and WN encephalitis respectively, that were negative by the IIF test.

Conclusion

Shell vial culture is a rapid and efficient tool for the etiological diagnosis of JE, WN and Den-2 encephalitis cases. Early, prompt collection, transport and processing of the CSF samples, would make SVC a better method for the rapid diagnosis of these flaviviral infections.

The effect of polyethylene glycol (PEG) on the isolation of Chlamydia trachomatis in H-1 HeLa cells

One hundred and ninety-six urethral and endocervical swabs were processed for isolation of C. trachomatis, using H-1 HeLa cells on shell vials, in the presence and absence of 7% PEG in the chlamydial overlay medium. The results were divided into three evaluable groups based on the number of inclusions per coverslip in the shell vials without PEG. The number of inclusions were compared with that of PEG-treated cultures using the paired t-test. The ranges for the three evaluable groups were one to ten, 11-100 and 101-1000 inclusions per coverslip. All three groups showed a significant increase (2.8- to 3.8-fold) in the number of inclusion bodies in the PEG-treated cultures compared to the untreated cultures.

Current methods of laboratory diagnosis of Chlamydia trachomatis infections

Infections caused by Chlamydia trachomatis are probably the most common sexually transmitted diseases in the United States. Commonly unrecognized and often inadequately treated, chlamydial infections can ascend the reproductive tract and cause pelvic inflammatory disease, which often results in the devastating consequences of infertility, ectopic pregnancy, or chronic pelvic pain. C. trachomatis infections are also known to increase the risk for human immunodeficiency virus infection. The obligate intracellular life cycle of C. trachomatis has traditionally required laboratory diagnostic tests that are technically demanding, labor-intensive, expensive, and difficult to access. In spite of these historical challenges, however, laboratory diagnosis of C. trachomatis has been a rapidly advancing area in which there is presently a wide array of commercial diagnostic technologies, costs, manufacturers. This review describes and compares the diagnostic methods for C. trachomatis infection that are currently approved for use in the United States, including the newest DNA amplification technologies which are yet to be licensed for commercial use. Issues to consider in selecting a test for purposes of screening versus diagnosis based on prevalence, performance, legal, social, and cost issues are also discussed.

Evaluation of two ELISA's for detecting Chlamydia trachomatis from endocervical swabs

Two enzyme immunoassays (EIAs) detecting Chlamydia trachomatis from endocervical swabs, Syva MicroTrak (MT) and Abbott Chlamydiazyme (CZ), were compared with a tissue culture (TC) standard. Initially, 8% (100 of 1250) of specimens were TC positive, yielding sensitivities of 94% (94 of 100) for MT and 79% (79 of 100) for CZ with identical 98% specificities (1129 of 1150 for MT and 1130 of 1150 for CZ). Discrepant specimens were retested by both EIAs and assayed for elementary bodies (EBs) by a fluorescent antibody test. After discrepancy analysis, 9.5% (118) of 1240 patients were either TC or EB positive, yielding sensitivities of 94.1% for MT (111 of 118) and 79.7% for CZ (94 of 118) with identical specificities of 100% (1122 of 1122). These results indicate that the MT is significantly more sensitive (p less than 0.05, McNemar test) than CZ in detecting C. trachomatis from endocervical swabs.

Interaction of chlamydiae and host cells in vitro

The obligately intracellular bacteria of the genus Chlamydia, which is only remotely related to other eubacterial genera, cause many diseases of humans, nonhuman mammals, and birds. Interaction of chlamydiae with host cells in vitro has been studied as a model of infection in natural hosts and as an example of the adaptation of an organism to an unusual environment, the inside of another living cell. Among the novel adaptations made by chlamydiae have been the substitution of disulfide-bond-cross-linked polypeptides for peptidoglycans and the use of host-generated nucleotide triphosphates as sources of metabolic energy. The effect of contact between chlamydiae and host cells in culture varies from no effect at all to rapid destruction of either chlamydiae or host cells. When successful infection occurs, it is usually followed by production of large numbers of progeny and destruction of host cells. However, host cells containing chlamydiae sometimes continue to divide, with or without overt signs of infection, and chlamydiae may persist indefinitely in cell cultures. Some of the many factors that influence the outcome of chlamydia-host cell interaction are kind of chlamydiae, kind of host cells, mode of chlamydial entry, nutritional adequacy of the culture medium, presence of antimicrobial agents, and presence of immune cells and soluble immune factors. General characteristics of chlamydial multiplication in cells of their natural hosts are reproduced in established cell lines, but reproduction in vitro of the subtle differences in chlamydial behavior responsible for the individuality of the different chlamydial diseases will require better in vitro models.

Comparison of cotton wool swab and cytobrush for detection of chlamydial infection in women attending a genitourinary medicine clinic

Endocervical specimens obtained by cytobrush and conventional cotton wool swabs from 90 women attending a genitourinary medicine clinic were compared for their efficiency in detecting chlamydial infection. Isolation of Chlamydia trachomatis and detection of the chlamydial lipopolysaccharide antigen were attempted on each specimen. Antigen was detected in 18% of cytobrush and 17% of swab specimens. The cytobrush proved less suitable than swabs for isolation because 8 cytobrush specimens (9%) were toxic to the McCoy cells. Toxicity was significantly associated with an infected endocervix (2P = 0.004). Cytobrush therefore appeared to have little advantage over the much cheaper alternative, the cotton wool swab.

TestPack Chlamydia, a new rapid assay for the direct detection of Chlamydia trachomatis

TestPack Chlamydia (Abbott Laboratories) is a rapid enzyme immunoassay for the direct antigen detection of Chlamydia trachomatis in endocervical specimens. The assay is self-contained, requires no specialized equipment, and yields results in less than 30 min. The clinical performance of TestPack Chlamydia versus chlamydial cell culture was evaluated with a total of 1,694 paired endocervical specimens. Discordant samples were further investigated by immunofluorescent staining and by Chlamydiazyme immunoassay, with confirmatory procedures. The sensitivity of TestPack Chlamydia with less-than-48-h-old specimens was 76.5%, while culture sensitivity was 86.7%. TestPack Chlamydia specificity was determined to be 99.5%. These results indicate that TestPack Chlamydia is an accurate test for chlamydial infection, with a positive predictive value of 96.2%. This assay is suitable for low-volume chlamydial testing in physician offices, clinics, and smaller laboratories.

Laboratory diagnosis of human chlamydial infections

Chlamydia trachomatis is a human pathogen that causes ocular disease (trachoma and inclusion conjunctivitis), genital disease (cervicitis, urethritis, salpingitis, and lymphogranuloma venereum), and respiratory disease (infant pneumonitis). Respiratory chlamydioses also occur with infection by avian strains of C. psittaci or infection by the newly described TWAR agent. Diagnosis of most acute C. trachomatis infections relies on detection of the infecting agent by cell culture, fluorescent antibody, immunoassay, cytopathologic, or nucleic acid hybridization methods. Individual non-culture tests for C. trachomatis are less sensitive and specific than the best chlamydial cell culture system but offer the advantages of reduced technology and simple transport of clinical specimens. Currently available nonculture tests for C. trachomatis perform adequately as screening tests in populations in which the prevalence of infection is greater than 10%. A negative culture or nonculture test for C. trachomatis does not, however, exclude infection. The predictive value of a positive nonculture test may be unsatisfactory when populations of low infection prevalence are tested. Tests that detect antibody responses to chlamydial infection have limited utility in diagnosis of acute chlamydial infection because of the high prevalence of persistent antibody in healthy adults and the cross-reactivity due to infection by the highly prevalent C. trachomatis and TWAR agents. Assays for changes in antibody titer to the chlamydial genus antigen are used for the diagnosis of respiratory chlamydioses. A single serum sample that is negative for chlamydial antibody excludes the diagnosis of lymphogranuloma venereum.

Chlamydia trachomatis: a currently recognized pathogen of tonsillitis

The authors investigated whether or not Chlamydia trachomatis could be isolated from tonsillar crypts in order to establish directly the relationship of the organism to the tonsillar infection. In 17 of 65 (26.2%) cases with tonsillitis, C. trachomatis was recovered from tonsillar crypts. Ten of the 17 Chlamydia-positive patients were attended for recurrent sore throat and 5 for lingering tonsillitis. Thirteen of the 17 cases had serum antibody to C. trachomatis. We also isolated this microorganism from one of 18 persons complaining of a lumpy throat. Eleven of the 18 Chlamydia-positive patients had pertinent histories of oro-genital sexual activity, and pharyngeal infection apparently resulted from direct inoculation. The available data suggest that tonsillitis, the most common problem in otorhinolaryngology, may be caused by C. trachomatis more often than has been suspected.

Evaluation of an enzyme immunoassay for the diagnosis of chlamydial infections in urogenital specimens

A total of 194 male urethral and 402 cervical specimens were obtained from patients at the venereal disease outpatient clinic of University Hospital, Rotterdam, The Netherlands, to evaluate the IDEIA test (Boots Celltech) for the detection of chlamydial infections. The prevalences of culture-positive males and females were 17.5 and 8.2%, respectively. The respective overall sensitivities and specificities found were 67.6 and 93.7% for the males and 63.6 and 93.8% for the females. The highest sensitivity (83.3%) was found in male patients with more than 20 leukocytes per field in the sediment of the first-voided urine (magnification, X250) and in women with more than 10 leukocytes per field in a cervical Gram stain (magnification, X800). However, in men without urethritis and in women with fewer than 10 leukocytes per field in the Gram stain, sensitivities of 44.4 and 40%, respectively, were found. Culture-positive, IDEIA-negative results were predominantly observed in samples with few inclusions in the culture.

Evaluation of the direct fluorescent antibody test for diagnosis of chlamydial infections

The direct fluorescent antibody test and two culture methods were compared for accurate diagnosis of chlamydial infections. Using the same samples, 109 were found to be positive in the microtitre method with the direct confirmation test without subpassage, whereas 66 were positive in the vial method with Giemsa staining and subpassage. The direct test was evaluated for accuracy using cervical and male urethral specimens. Specimens for culture were obtained prior to sampling for the direct test. For cervical samples the sensitivity of the direct test, with the vial method taken as reference, appeared to be 72.2% with a specificity of 93.5%. With the microtitre method as standard, these values were 55.9% and 91.3%, respectively for females, and for male patients 49% and 95.6%, respectively. For cervical samples, in which sampling for the direct test was carried out prior to sampling for culture, the values were 46.3% and 93.2% respectively. Both culture method and study population influenced the sensitivity of the direct test. According to our findings, the direct test cannot replace the culture method for diagnosis of chlamydial infections.

Comparison of econazole and isoconazole as single dose treatment for vaginal candidosis

In a single blind trial there was no significant difference between econazole (2 X 150 mg pessaries) and isoconazole (2 X 300 mg pessaries) given as a once only treatment for vaginal candidosis. Cure rates at 14 days were 70.4% for econazole and 77.6% for isoconazole, and at 28 days were 63.8% and 64.5% respectively. Though isoconazole was formulated for single dose usage, econazole was formulated for a regimen of one pessary a night for three nights.

Conventional tissue culture compared with rapid immunofluorescence for identifying Chlamydia trachomatis in specimens from patients attending a genitourinary clinic

Specimens collected from 182 patients with histories suggesting chlamydial disease were examined by conventional culture and direct immunofluorescence techniques. Chlamydia trachomatis was identified by both methods in 57% of all patients. There was no significant difference between the two methods in detecting C trachomatis. Where a tissue culture service is not already established, cost analysis in individual departments may justify the use of the immunofluorescence method.

Effect of swab type and storage temperature on the isolation of Chlamydia trachomatis from clinical specimens

We evaluated various swabs for the recovery of Chlamydia trachomatis and found that only 7 of 14 swabs tested resulted in a greater than 50% recovery of organisms. Storage of chlamydial specimens at 4 degrees C for more than 1 day resulted in a rapid loss of viability, whereas freezing of specimens at -70 degrees C resulted in only a marginal decrease in the isolation rate.

Monoclonal antibody for rapid laboratory detection of cytomegalovirus infections: characterization and diagnostic application

Monoclonal antibodies to early (2H2.4, molecular weight 72,000 daltons) and late (2F3.0, molecular weight 68,000 daltons) antigens of the AD-169 strain of cytomegalovirus (CMV) were prepared by fusing mouse spleen cells with NS-1 mouse myeloma cells. The 2H2.4 monoclonal antibody produced a dense immunofluorescence with prominent lobular staining within the nucleus of CMV-infected substrate cells, whereas the reaction of 2F3.0 was more diffuse and generally involved the entire nucleus of the cells. Both monoclonal antibodies had little or no neutralizing activity against CMV in plaque-reduction assays. No cross-reactions were observed between these monoclonal antibodies and other members of the herpesvirus group. The 2H2.4 monoclonal antibody to early CMV antigen was used in a shell vial assay with a low-speed centrifugation step for the rapid (within 16 hours after inoculation) diagnosis of CMV infections. Optimal conditions for the test included centrifugation of shell vials at 700 X g for 45 minutes at 36 degrees C. An inoculum volume of 0.2 ml provided a reasonable balance between the optimal sensitivity for detecting specific viral fluorescence and the easy discrimination of the specific immunofluorescence from the background debris. Because of the commercial availability of the monoclonal antibody and the simplicity of the procedures used in the shell vial assay and subsequent fluorescence techniques, this rapid assay can be done in any laboratory that is familiar with cell culture manipulations.

Role of Chlamydia trachomatis in acute pharyngitis in young adults

It has recently been suggested that Chlamydia trachomatis may be a common cause of acute pharyngitis in adults. In a prospective investigation of 95 college students with acute pharyngitis, C. trachomatis was not isolated from any pharyngeal cultures. Further investigations are needed to better define the role of C. trachomatis in upper respiratory tract infections.

Advantages of adding a course of tetracycline to single dose ampicillin and probenecid in the treatment of gonorrhoea

Chlamydia trachomatis was reisolated from 11 of 12 men with gonorrhoea who had initially yielded chlamydiae and who had been treated with ampicillin and probenecid (AMP) only, but from none of five such men treated with ampicillin and probenecid followed by tetracycline (AMPT). These results correlated with the absence of postgonococcal urethritis (PGU) in the group treated with AMPT. C trachomatis was isolated or reisolated from 20 of 25 women after treatment with AMP, compared with none of 14 women treated with AMPT. We recommend the addition of a course of tetracycline to the routine single dose treatment for gonorrhoea in men and women.

Rapid detection of cytomegalovirus in MRC-5 cells inoculated with urine specimens by using low-speed centrifugation and monoclonal antibody to an early antigen

A commercially available monoclonal antibody directed against an early nuclear protein of cytomegalovirus was used with low-speed centrifugation for the rapid detection of this virus from urine specimens inoculated onto MRC-5 cells. A total of 19 of 162 (11.7%) urine specimens inoculated were positive by both immunofluorescence and peroxidase-antiperoxidase procedures (sensitivity, 100%), whereas only 18 of the samples produced cytopathic effects in conventional cell culture (specificity, 94.7%). All specimens were positive by immunofluorescence and peroxidase-antiperoxidase procedures at 36 h postinfection, whereas an average of 9 days was required for cytopathic effects to develop in cell cultures.

Survival of Chlamydia trachomatis in different transport media and at different temperatures: diagnostic implications

We compared the survival of a laboratory strain of Chlamydia trachomatis serovar L-2 in different media and at different temperatures (room temperature, 4 degrees C, and -70 degrees C). At these temperatures the best storage medium was 2SP (0.2 mol/l sucrose in 0.02 mol/l phosphate buffer supplemented with 10% fetal calf serum). We used material obtained from patients to study the sensitivity of the culture method as a function of sample storage time and temperature. Compared with results on direct inoculation, material stored in 2SP for 48 hours gave 11% fewer positive cultures at 4 degrees C and 14% fewer at room temperature. Of samples which gave negative results on direct inoculation, 4% were positive after storage at 4 degrees C for 48 hours and 2% after storage at -70 degrees C for a week. As expected, the number of inclusion forming units in the original material proved to be important for the percentage of positive cultures among the stored samples.

The effect of Ureaplasma urealyticum on semen characteristics

Semen samples from 280 men were cultured for Ureaplasma. The presence of Ureaplasma in the male genital tract did not affect ejaculate volume, motility, viability, or morphology. Sperm concentration was significantly lower in the presence than in the absence of Ureaplasma. The longevity of sperm as evaluated by sperm motility and viability at different intervals of time was also not influenced by the presence of Ureaplasma. Biochemical parameters, namely zinc, magnesium, acid phosphatase, and fructose were not affected by the presence of Ureaplasma. No relationship of Ureaplasma with sperm antibodies, aerobic infection, or anaerobic infection was observed.

Comparison of two commercially available isolation systems for Chlamydia trachomatis

In a comparison of two commercially available chlamydial isolation systems in which cycloheximide-treated McCoy cell monolayers are used, the system from Bartels Immunodiagnostic Supplies, Inc., Bellevue, Wash., was found to be superior to that from M. A. Bioproducts, Walkersville, Md. for the detection of Chlamydia trachomatis by iodine staining. Of 288 clinical specimens run in parallel, 47 (16.3%) were positive, with 16 of 47 positive results detected in the Bartels system only and 1 of 47 positive results detected in the M. A. Bioproducts system only (P less than 0.001). A comparison of the number of inclusion-forming units per cover slip from clinical specimens and passaged isolates also showed that the Bartels cell system demonstrated higher inclusion counts than the M. A. Bioproducts system. In routine clinical use, overall isolation rates were higher (P less than 0.001) and contamination rates were lower (P less than 0.001) with the Bartels system as compared with results obtained in a previous time period in which the M. A. Bioproducts system was used.

Comparison of reticulate and elementary body antigens in detection of antibodies against Chlamydia trachomatis by an enzyme-linked immunosorbent assay

Reticulate bodies from a type C and elementary bodies from a type L2 strain of Chlamydia trachomatis were isolated and used as antigens in an enzyme-linked immunosorbent assay (ELISA). Results obtained for human sera with these two antigens used in the ELISA were compared with each other and with results obtained for the same sera by the micro-immunofluorescence test. Negative control populations included cloistered nuns and children with respiratory infections. Populations at risk for chlamydial infection consisted of 42 men with nongonococcal urethritis attending a sexually transmitted diseases clinic and 42 college women who had contact with men with nongonococcal urethritis. ELISAs done with the two antigens were equivalent to each other and to the micro-immunofluorescence test in the ability to predict the presence or absence of infection. None of the tests had high predictive values for the men with urethritis. However, the negative predictive value of both the micro-immunofluorescence test and the elementary body ELISA was 0.92 for the college women. Such serological tests may be of value in screening selected populations for subclinical infections with C. trachomatis.

Trachoma in South Africa

Trachoma remains the most common cause of preventable blindness in certain areas of the northern Transvaal region of South Africa. Results of epidemiological studies in the area indicate that trachoma is a familial disease with young children acting as the main source of infection within the family. Elderly women who have lived in these areas for long periods of time are at greater risk of blindness and impaired vision from the disease. Genital tract carriage of Chlamydia trachomatis is relatively infrequent in these trachoma-endemic areas and no evidence of eye-to-eye transmission of oculo-genital serotypes of C. trachomatis could be demonstrated.

Chlamydial screening of pregnant women in a sexually transmitted diseases clinic

Fifty-three consecutive pregnant women seen over six months were screened for chlamydial infection, syphilis, gonorrhoea, trichomoniasis, and candidosis. Chlamydia trachomatis was isolated in 20 (37.7%) patients, of whom six were sexual partners of known cases of non-gonococcal urethritis (NGU) (two had associated gonorrhoea or candidosis) and six had gonorrhoea (three had associated trichomoniasis and candidosis). If treatment is given to contacts of NGU 14 patients with other presenting conditions would not have been treated unless chlamydial cultures had been performed. This may lead to potentially serious complications of chlamydial infection in both mothers and neonates.

Chlamydia trachomatis in general practice: a preliminary report

A case of Chlamydia trachomatis diagnosed in general practice is described. It is argued that, in the future, the culture methods used in this study, together with the application of at risk criteria, could identify in general practice most patients suffering from chlamydial disease.

Provision of a chlamydial culture service to a sexually transmitted diseases clinic

Urethral specimens from 215 men were inoculated on to McCoy cell cultures, both at the local laboratory and at a central reference laboratory, Chlamydia trachomatis was isolated from 58 (28%) patients; 12 of these isolates were, however, obtained only at the local laboratory. The results show the feasibility and convenience of a central laboratory supplying a peripheral laboratory with uninoculated prepared cell cultures. Such a service is not only more cost effective but obviates the problems of transporting specimens to a central laboratory.

Rosaramicin and tetracycline in the treatment of non-gonococcal urethritis. A comparison of clinical and microbiological results

The clinical and microbiological outcome of the treatment of 94 men for uncomplicated non-gonococcal urethritis (NGU) was studied. Rosaramicin 250 mg six hourly for seven days was given to 46 men and tetracycline 250 mg six hourly for seven days to 48 men; the follow-up period was up to six weeks. Complete resolution of the clinical signs of infection was seen in 40 (87%) of the men treated with rosaramicin and in 37(77%) of those treated with tetracycline. Chlamydia trachomatis was eliminated from 17 of the 18 men treated with rosaramicin and from all of the 16 men treated with tetracycline. Ureaplasma urealyticum was eliminated from 12 of the 14 men treated with rosaramicin and from 15 of the 19 receiving tetracycline. Clinical recovery correlated well with the elimination of C trachomatis but less well with that of U urealyticum. The two antimicrobial agents were equally effective in the therapy of NGU, but gastrointestinal side effects were significantly more common in men treated with rosaramicin.

Epidemiology of chlamydial infection of the human genital tract: evidence for the existence of latent infections

A group of 536 women attending a clinic for sexually transmitted diseases was investigated for cervical infection by Neisseria gonorrhoeae and Chlamydia trachomatis. Conclusions have been reached concerning the existence and significance of latent and subclinical chlamydial infection of the female genital tract, and on the sexual infectivity of Chlamydia trachomatis to women. The results of the study indicate (1) demonstrable chlamydial infection in 25% of all women attending the clinic for the first time, and in 11% of those with unknown contact history; (2) sexual transmission of Chlamydia trachomatis; 45% of women exposed to chlamydiae contract the infection compared with 75% of those exposed to Neisseria gonorrhoeae; (3) the possibility of reactivation of latent chlamydial infection by Neisseria gonorrhoeae in some women.

Microbiology Diagnosis of chlamydia trachomatis infection

The etiological diagnosis of what is today known as infection by Chlamydia trachomatis was first made possible in 1907 when Halberstaedter and von Prowazek identified inclusions in conjunctival scrapings by means of Giemsa staining. C. trachomatis was originally classified as a virus, and the culture systems used were those for viruses. Macchiavello was the first to describe the isolation of C. trachomatis in embryonated hens' eggs (1944), but the first isolation is usually credited to T'ang and co-workers (1957), also using eggs. A major step in the understanding of chlamydial infections was made in 1965 when Gordon and Quan published a paper on the use of irradiated McCoy cells for isolation purposes. This technique made it possible to perform cultures from genital specimens with simplicity in comparison to isolation from eggs. Various culture techniques have been developed parallel to the expanding knowledge of the basic biology of the genus Chlamydia. McCoy cells (mouse fibroblasts), HeLa 229 (derived from human cervical carcinoma cells) and BHK-21 cells (baby hamster kidney cells) are the cell types regularly used for the culture of C. trachomatis. The principles underlying the various culture techniques are discussed. A description of the original irradiated McCoy cell system and the simplified, sensitive technique using cycloheximide-treated McCoy cells are given in this paper.

Isolation of Chlamydia trachomatis from women with urethral syndrome

Urethral swabs were examined for Chlamydia trachomatis in 22 women suffering from urethral syndrome and in an age-matched control group without genito-urinary symptoms. Full urodynamic investigation was done in patients with urinary symptoms. In this group the isolation rate of C. trachomatis was significantly higher than in the control group (59% versus 13%, P less than 0.01). Therefore C. trachomatis must be considered as one of the possible causes of the female urethral syndrome. Five out of eight patients with positive culture who were treated with minocycline had a negative follow-up culture and the clinical results of this treatment were variable.

Cultural method for large-scale screening for Chlamydia trachomatis genital infection

Idoxuridine-treated McCoy cells grown as monolayers in 96 well microplates provide a convenient method for the isolation of Chlamydia trachomatis. Staining of infected monolayers with periodic acid-Schiff reagent (PAS) allows easy recognition of C trachomatis inclusions without the need for dark-ground microscopy. By this method 384 clinical specimens can be examined concurrently. It is sufficiently sensitive to form the basis of a chlamydial culture service for patients attending Sexually Transmitted Diseases (STD) Clinics.

Epidemiological and clinical correlates of chlamydial infection of the cervix

Of 474 women studied to identify epidemiological and clinical correlates of chlamydial infection of the cervix, Chlamydia trachomatis was isolated from 158 (33.3%) of all women, from 48.3% of those infected with Neisseria gonorrhoeae, from 43% of the sexual consorts of men with nongonococcal urethritis, and from 74% of those whose consorts were also infected with C trachomatis. C trachomatis was the sole pathogen found in 58 women. Age, marital state, occupation, past history of gonorrhoea, menstrual state, and symptoms had no predictive value. The isolation of C trachomatis was significantly associated with N gonorrhoeae, the use of oral contraceptives, cervical ectopy, cervicitis, and last sexual exposure more than one week previously. Except for three patients, none of the criteria alone or in combination was reliable enough to predict with acceptable accuracy that the 30 chlamydia-positive women among the 191 who were not infected with N gonorrhoeae and whose consorts were not known to have urethritis harboured chlamydia.

Taking cell cultures to the patient in an attempt to improve chlamydial isolation

McCoy cell cultures were inoculated with 121 urethral and cervical specimens taken from patients attending one of two sexually transmitted disease clinics. The mean number of Chlamydia trachomatis inclusions was greater when the cultures were inoculated with the specimens and centrifuged in the clinic than when the specimens were first stored in liquid nitrogen. Furthermore, 18 of the 29 chlamydia-positive specimens produced larger numbers of of inclusions when inoculated immediately. Despite this, the isolation rate from specimens inoculated directly (22%) was about the same as from specimens which had been frozen (21%). Of the 30 occasions on which the cell monolayers were disrupted, 29 followed immediate inoculation. This may possibly have been due to some toxic factor in some of the specimens.

Evaluation of preservation methods and solid media suitable for recovery of Ureaplasma urealyticum from transported urine specimens

Urine specimens to be tested for Ureaplasma urealyticum (T-strain mycoplasma) must often be transported to a central laboratory for identification. To examine survival of these organisms over 2 days of transport, fresh urine samples were tested for the presence of ureaplasmas and then divided into four groups: (i) fresh, (ii) frozen, (iii) preserved with 1% (wt/vol) boric acid at room temperature, and (iv) preserved with 10% dimethyl sulfoxide and frozen. The samples were cultured on both A7 and New York City solid media, and the estimates of survival were compared to that of fresh urine. Less than 10% survival of Ureaplasma was observed in 11 of 14 specimens stored frozen for 2 days without preservation; six specimens lost all organisms. Specimens containing either dimethyl sulfoxide or boric acid showed higher survival rates, although neither method consistently approached the full recovery of the T-strains found with the fresh urine. Ureaplasmas from fresh specimens grew well on both New York City and A7 media; however, the New York City medium proved superior for those preserved with boric acid and for urine samples containing few ureaplasmas. These results indicate that preservation of samples does increase the yield of U. urealyticum from urine samples delayed in transit.

Maternal and infantile infection with Chlamydia in a Swedish population

Chlamydia trachomatis was isolated from 2.4% of 1 328 puerperal women. The frequency was highest in the age group below 20 years and thereafter decreased with increasing age. Chlamydial conjunctivitis was confirmed in 0.4% of the infants. Two additional cases of conjunctivitis occurred among the exposed infants but chlamydia cultures were not obtained. In a separate ophthalmological material of neonatal conjunctivitis a third of the cases developing within the first month of life was associated with chlamydia. The early and sharp incidence peak for chlamydial conjunctivitis suggested that transmission occurred at delivery. No cases of chlamydial pneumonia were noted. Peroral chemotherapy is recommended in infants for systemic eradication of C. trachomatis.

Evidence of Chlamydia trachomatis infection in sexually acquired reactive arthritis

Thirty male patients with sexually acquired reactive arthritis (SARA) have been studied at the time of their initial presentation and thereafter. Chlamydia trachomatis was isolated from the urethral exudate of 9 (36.0%) of the 25 patients from whom urethral specimens were taken, and elevated titres of IgM antibody of C. trachomatis were detected in 11 (36.6%) of the 30 initial sera. Thirteen (43.3%) of the patients has a positive urethral culture and/or elevated titre of IgM antibody, and it is therefore suggested that 43.3% of these patients suffered an acute chlamydial infection at or near the time of the onset of their joint disease. The demonstration of 4-fold or greater rises and/or falls in IgM antibody titre (8 patients) and IgG antibody titre (6 patients) in a group of 15 men studied throughout the course of their disease strongly supports this conclusion. A positive urethral culture and/or raised titre of IgM serum antibody was also detected in 25 (50%) of 50 men with uncomplicated nongonococcal urethritis (NGU), suggesting that the prevalence of chlamydial infections in the 2 conditions is similar. Titres of IgG serum antibody to C. trachomatis were, however, significantly higher in patients with SARA than in those with NGU or other rheumatic diseases, and in healthy controls. The geometric mean titres (GMT) of IgG serum antibody in patients with SARA, NGU, rheumatoid arthritis, ankylosing spondylitis, systemic lupus erythematosus, and in healthy controls were 1:47.5, 1:8.6, 1:2.2, 1;2.2, 1:3.5, and 1:1.4, respectively. These findings suggest that an exaggerated antibody response to acute infection by C. trachomatis may be an important factor in the development of SARA in some but not all patients.

Chlamydial antigens stabilized with formalin for use in the micro-immunofluorescence test

Formalinized antigen suspensions prepared by differential centrifugation from crude infected yolk sacs and stored at 4 degrees C were satisfactory antigens during at least 36 weeks when used in chlamydial micro-immunofluorescence procedures.

Single-dose minocycline in the treatment of gonococcal urethritis. Clinical efficacy in relation to bacterial resistance and its effects on associated Chlamydia trachomatis infections

Seventy-two men with gonococcal urethritis were given a single 300-mg dose of minocycline. The failure rate was 13% and the trial was terminated at an early stage. Failure was correlated with increased resistance of Neisseria gonorrhoeae to minocycline. The activity of penicillin, spectinomycin, erythromycin, tetracycline, sulphamethoxazole, cefuroxime, cefotaxime, rosamicin, thiamphenicol, and piperacillin against N. gonorrhoeae were examined in vitro. With the exception of spectinomycin, parallel patterns of resistance to the other antibiotics and minocycline were found. Resistance to spectinomycin was not found, confirming the usefulness of this antibiotic in the treatment of gonorrhoea. The incidence of PGU was significantly lower after a single dose of minocycline than in previous studies.

The need for a chlamydial culture service

In a prospective study of unselected, female patients attending a sexually transmitted disease clinic one in eight patients would have been errouneously declared free of infection in the absence of a chlamydial culture service. Chlamydia trachomatis is now accepted as a causative organism of non-specific urethritis and post-gonococcal urethritis in men and non-specific genital infection in women. Thus, facilities for isolation of C. trachomatis should be an essential aid in the management of women attending STD clinics. Male patients would also benefit if such facilities were readily available.

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.