A novel real-time PCR to detect Chlamydia trachomatis in first-void urine or genital swabs

Chlamydia trachomatis as a Current Health Problem: Challenges and Opportunities

Chlamydia is one of the most common sexually transmitted bacterial infections (STIs) worldwide. It is caused by Chlamydia trachomatis (CT), which is an obligate intracellular bacterium. In some cases, it can occur in coinfection with other parasites, increasing the pathologic potential of the infection. The treatment is based on antibiotic prescription; notwithstanding, the infection is mostly asymptomatic, which increases the risk of transmission. Therefore, some countries have implemented Chlamydia Screening Programs in order to detect undiagnosed infections. However, in Portugal, there is no CT screening plan within the National Health Service. There is no awareness in the general healthcare about the true magnitude of this issue because most of the methods used are not Nucleic Acid Amplification Technology-based and, therefore, lack sensitivity, resulting in underreporting infection cases. CT infections are also associated with possible long-term severe injuries. In detail, persistent infection triggers an inflammatory milieu and can be related to severe sequels, such as infertility. This infection could also trigger gynecologic tumors in women, evidencing the urgent need for cost-effective screening programs worldwide in order to detect and treat these individuals adequately. In this review, we have focused on the success of an implemented screening program that has been reported in the literature, the efforts made concerning the vaccine discovery, and what is known regarding CT infection. This review supports the need for further fundamental studies in this area in order to eradicate this infection and we also suggest the implementation of a Chlamydia Screening Program in Portugal.

Evaluation of a Multiplex Real-Time PCR Assay for Detecting Chlamydia trachomatis in Vaginal Samples

Chlamydia trachomatis is an important cause of sexually transmitted infections (STI) in Western countries. It is often asymptomatic, and thus, left untreated, and can have severe negative consequences, such as tubal infertility or adverse pregnancy outcomes. Other sexually transmitted microorganisms, such as Neisseria gonorrhoeae and Trichomonas vaginalis, as well as normal residents of the vaginal flora, such as genital mycoplasmas, also negatively impact human sexual and reproductive health. We evaluated the reliability of the Seegene Allplex STI Essential Assay for C. trachomatis detection using the real-time qPCR routinely used in our diagnostic laboratories as the gold standard. The Seegene assay displayed a sensitivity of 97.8% and a specificity of 98.9%. As this assay can also detect six other urogenital pathogens, we applied it to 404 samples from women who attended Lausanne University Maternity Hospital and obtained the following prevalence rates: 2.5% for C. trachomatis, 3.5% for Mycoplasma hominis, 6.3% for Ureaplasma urealyticum, and 27.7% for Ureaplasma parvum. Two samples were positive for Trichomonas vaginalis, and one sample was positive for Mycoplasma genitalium. Bacterial vaginosis was present in 4.5% of the cases and was strongly associated with M. hominis. Finally, we confirmed the association between C. trachomatis infection and pre-term birth (p = 0.03) but could not detect any association of this condition with other urogenital pathogens (Mycoplasma/Ureaplasma). In conclusion, given its high sensitivity and specificity for C. trachomatis DNA detection as well as its multiplex format, which simultaneously provides results for six other urogenital pathogens, the Seegene Allplex™ STI Essential Assay represents an appealing diagnostic tool in modern microbiology laboratories.

Diagnostic value of the QuickStripe™ chlamydia rapid test among high-risk women in Jakarta

BACKGROUND

Difficulty in diagnosing Chlamydia trachomatis infections, including chlamydial cervicitis, is a notable challenge in managing sexually transmitted infections in Indonesia. Gram staining is usually done to make a presumptive diagnosis despite its low sensitivity and specificity. Polymerase chain reaction (PCR) is considered the gold standard, but it is costly, technically demanding, and difficult to be performed in low-resource settings. Thus, rapid point-of-care tests with high sensitivity and specificity are needed to diagnose chlamydial cervicitis.

METHODS

This cross-sectional study included symptomatic and asymptomatic high-risk women in the Mulya Jaya Sex Workers Rehabilitation Center in June to July 2020. Endocervical swabs from each participant were taken for QuickStripe™ chlamydia rapid test (CRT), Gram staining, and real-time PCR.

RESULTS

A total of 41 participants were enrolled. The sensitivity and specificity for QuickStripe™ CRT were 73.6% (95% CI: 48.80%-90.85%) and 81.82% (95% CI: 59.72%-94.81%). Positive and negative predictive values were 77.78% (95% CI: 58.09%-89.84%) and 78.05% (95% CI: 62.39%-89.44%). Proportion of chlamydial cervicitis in study participants based on real-time PCR was 46.3%.

CONCLUSIONS

We concluded that QuickStripe™ CRT can be recommended as an alternative diagnostic test for high-risk populations in Jakarta.

Single gene targeted nanopore sequencing enables simultaneous identification and antimicrobial resistance detection of sexually transmitted infections

OBJECTIVES

To develop a simple DNA sequencing test for simultaneous identification and antimicrobial resistance (AMR) detection of multiple sexually transmitted infections (STIs).

METHODS

Real-time PCR (qPCR) was initially performed to identify Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), Mycoplasma genitalium (MG) and Trichomonas vaginalis (TV) infections among a total of 200 vulvo-vaginal swab samples from female sex workers in Ecuador. qPCR positive samples plus qPCR negative controls for these STIs were subjected to single gene targeted PCR MinION-nanopore sequencing using the smartphone operated MinIT.

RESULTS

Among 200 vulvo-vaginal swab samples 43 were qPCR positive for at least one of the STIs. Single gene targeted nanopore sequencing generally yielded higher pathogen specific read counts in qPCR positive samples than qPCR negative controls. Of the 26 CT, NG or MG infections identified by qPCR, 25 were clearly distinguishable from qPCR negative controls by read count. Discrimination of TV qPCR positives from qPCR negative controls was poorer as many had low pathogen loads (qPCR cycle threshold >35) which produced few specific reads. Real-time AMR profiling revealed that 3/3 NG samples identified had gyrA mutations associated with fluoroquinolone resistance, 2/10 of TV had mutations related to metronidazole resistance, while none of the MG samples possessed 23S rRNA gene mutations contributing to macrolide resistance.

CONCLUSIONS

Single gene targeted nanopore sequencing for diagnosing and simultaneously identifying key antimicrobial resistance markers for four common genital STIs shows promise. Further work to optimise accuracy, reduce costs and improve speed may allow sustainable approaches for managing STIs and emerging AMR in resource poor and laboratory limited settings.

Decreased occurrence of endometriosis in women with Chlamydia trachomatis infection

PROBLEM

Despite abundant reports on the risk role of uterine outflow tract obstruction in endometriosis, information on the occurrence of endometriosis in women with Chlamydia trachomatis infection causing fallopian tube obstruction is unknown. We investigated the role of Chlamydia trachomatis infection with or without fallopian tubal patency in the occurrence of endometriosis.

METHODS

This is a retrospective case-controlled cohort study with 539 women who had laparoscopic surgery for several indications during the period between January, 2003 and June, 2010. Women with ectopic pregnancy, uterine anomaly, chromosomal abnormality, primary amenorrhea, and perimenopausal women were excluded. Endometriosis was diagnosed by laparoscopic inspection and confirmed by histopathology. Tubal patency was diagnosed by HSG or laparoscopic chromopertubation test. Presence of chlamydia infection was examined by RT-PCR and serological test.

RESULTS

Two-hundred and seven women were enrolled. Eighty-six (41.5%) women had chlamydia infection. Tubal patency and occurrence of endometriosis were significantly decreased among women with chlamydia infection comparing to women without it (P = .005 and P = .0008, respectively). Even among women with patent tube, laparoscopic detection of endometriosis was significantly decreased in chlamydia infected comparing to non-infected women (P = .02). Multiple logistic regression model revealed that previous history of chlamydia infection significantly decreased the occurrence of endometriosis, and was independent of age, menstrual status, parity and tubal patency (odds ratio .44; 95% confidence interval .24-.80; P = .007).

CONCLUSION

A decreased occurrence of peritoneal endometriosis was observed in women with Chlamydia trachomatis infection. The possible impairment of retrograde menstrual flow by chlamydia-infected tubal damage may decrease the risk of endometriosis.

Availability of Chlamydia trachomatis Testing and Its Importance in the Surveillance of Genital Chlamydial Infection

The reported prevalence of genital Chlamydia trachomatis infection (GCTI) is much lower in low-income countries than that in high-income countries. This study surveyed the prevalence of GCTI in 456 hospitals in Shandong province, China in December 2018. Among the hospitals surveyed, antigen testing, PCR testing, and either antigen or PCR testing were available in 200 (43.9%), 88 (19.3%), and 268 (58.8%) hospitals, respectively. PCR testing was more available in tertiary hospitals than in primary and secondary hospitals (χ² = 28.560, P = 0.000). Significant differences were observed in the availability of antigen testing (χ² = 15.708, P = 0.003), PCR testing (χ² = 22.494, P = 0.000), and either antigen or PCR testing (χ² = 21.729, P = 0.000) among different types of hospitals. In 2018, 1532 cases of GCTI were reported in 99 hospitals. Tertiary hospitals reported more cases than those in primary and secondary hospitals (χ² = 24.082, P = 0.000). The distribution of different types of hospitals that reported GCTI cases was consistent with that of hospitals that provided laboratory testing for GCTI. Antigen and PCR testing were only available in 200 (43.9%) and 88 (19.3%) hospitals, respectively. The results highlighted that the availability of laboratory testing for GCTI in Shandong province was poor, suggesting that the prevalence of GCTI in the province had been sorely underestimated.

Development of a new TaqMan-based PCR assay for the specific detection and quantification of Simkania negevensis

Simkania negevensis is an emerging Chlamydia-like bacterium related to human respiratory diseases. An early and accurate detection of this pathogen could be useful to monitor the potential infectious risks and to set suitable outbreak control measures. In Tunisia, distribution and abundance of S. negevensis remain until now largely unknown. In the present work, a qPCR assay, targeting the 16S rRNA gene, for fast detection and quantification of S. negevensis was developed and validated. A high specificity for S. negevensis detection displaying no cross-reaction with the closely related Chlamydia spp. or the other tested microorganisms was noticed. qPCR assay performance was considered very satisfying with detection limits of 5 DNA copies per reaction. qPCR assay validation was performed by screening 37 clinical specimens and 35 water samples. S. negevensis wasn't detected in respiratory samples, but it was found in four cases of water samples. We suggest that the qPCR assay developed in this study could be considered sufficiently characterized to initiate the quantification of S. negevensis in environmental samples.

Detection of chlamydia trachomatis infection among the pregnant women attending a tertiary care hospital in Kerala - South India by polymerase chain reaction

Background

Chlamydia trachomatis infection is the most prevalent bacterial sexually transmitted infection and may influence pregnancy outcome.

Aims and Objectives

This study was conducted to assess Chlamydial infection during pregnancy by PCR.

Materials and Methods

Study group consists of patients who are attending the antenatal clinics. Endocervical swabs were collected from 300 patients.

Results

Off the 300 samples tested, 29 were positive as per PCR which used CT F : 5' CGT GTC GGC AAT CCT GCT GAT 3' and CT R : 5' GTC GAT AAC ATA GTC ACG ATA GTC 3'as the primers.

Conclusion

This suggests there is a prevalence of Chlamydia trachomatis in our population which is 10%. Hence, it should be noted as a significant public health problem especially among sexually active young women of child bearing age. Timely detection and prompt treatment of Chlamydial infection during pregnancy can eliminate its adverse outcomes.

Is Chlamydia trachomatis PCR Detection from Cervical Canal Swabs Associated with Tubal Obstruction?

Objective: To determine the relationship between a Chlamydia trachomatis PCR positive diagnosis from cervical canal swabs and the presence of tubal diseases among infertile women in Vietnam.

Methods: In this cross-sectional descriptive study, women who sought infertility treatment at the Center for Reproductive Endocrinology & Infertility, Hue University Hospital, Vietnam, from June 2016 to June 2017 were enrolled. All study participants were interviewed, and PCR tests were then performed to diagnose Chlamydia from cervical canal swabs. Hysterosalpingogram (HSG) was carried out to examine the uterine cavity and fallopian tubes.

Results: Among 568 women whose mean age was 32.0 ± 5.1 years, the prevalence of C. trachomatis infection as detected by PCR was 5.8%. Eighty-one percent (460/568) of infertile women had normal HSG results, and abnormal HSG results were more frequent in women over 35 years old, in women with secondary infertility, and in those with a history of miscarriage or genital tract infection. However, there was no relationship between C. trachomatis PCR positivity and HSG results in infertile women.

Conclusions: The diagnosis of C. trachomatis infection using the cervical swabs is the useful but not an effective method for routine practice for predicting tubal obstruction in infertile women.

Rapid and accurate diagnosis of Chlamydia trachomatis in the urogenital tract by a dual-gene multiplex qPCR method

Introduction. Chlamydia trachomatis (C. trachomatis, CT) is an obligatory intracellular bacterium that causes urogenital tract infections and leads to severe reproductive consequences. Therefore, a rapid and accurate detection method with high sensitivity and specificity is an urgent requirement for the routine diagnosis of C. trachomatis infections.Aim. In this study, we aimed to develop a multiplex quantitative real-time PCR (qPCR) assay based on two target regions for accurate detection of C. trachomatis in urogenital tract infections.Methodology. Primers and probes based on the conserved regions of the cryptic plasmid and 23S rRNA gene were designed. Then, two qPCR assays were established to screen for the optimal probe and primers for each of the two target regions. Subsequently, the multiplex qPCR method was developed and optimized. For the diagnostic efficiency evaluation, 1284 urogenital specimens were tested by the newly developed multiplex qPCR method, an immunological assay and a singleplex qPCR assay widely used in hospitals.Results. The multiplex qPCR method could amplify both target regions in the range of 1.0×10²-1.0×10⁸ copies ml^-1 with a strong linear relationship, and lower limits of detection (LODs) for both targets reached 2 copies PCR^-1. For the multiplex qPCR method, the diagnostic sensitivity and specificity was 100.0 % (134/134) and 99.3 % (1142/1150), respectively. For the singleplex qPCR assay, the diagnostic sensitivity and specificity was 88.8 % (119/134) and 100.0 % (1150/1150), respectively. For the immunological assay, the diagnostic sensitivity and specificity was 47.0 % (63/134) and 100.0 % (1150/1150), respectively.Conclusion. In this study, a multiplex qPCR assay with high sensitivity and specificity for rapid (≤2.0 h) and accurate diagnosis of C. trachomatis was developed. The qPCR assay has the potential to be used as a routine diagnostic method in clinical microbiology laboratories.

Chlamydia Trachomatis Infection in High-Risk Human Papillomavirus Based on Cervical Cytology Specimen

Objective:

High-risk human papillomavirus (HR HPV) was associated with the development of cervical cancer. Asymptomatic Chlamydia trachomatis (C. trachomatis) infection is the most common bacterial, sexually-transmitted infection. This study aimed to investigate the association of C. trachomatis in positive HR HPV and the cytological results from liquid-based cytology (LBC).

Methods:

150 residual LBC specimens were collected; all of which had undergone cytology and HPV testing by Cobas. The samples were established as C. trachomatis using real-time PCR (RT-PCR) with Cryptic F/Cryptic R primers.

Results:

Of 150 positive HPV findings, the most common (72.7%, 109/150) were the 12 other HR HPVs (viz., 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68). The cervical cytology of those positive HR HPVs were mostly negative (70.0%, 105/150). The C. trachomatis infections in positive HR HPV were 16% (24/150) HPV. The analysis of the abnormal cytology revealed that 41.6% had C. trachomatis co-infection (C. trachomatis and HPV infection) viz., LSIL (20.8%), HSIL (12.5%), and ASC-US (8.3%). A comparison with positive HPV without C. trachomatis co-infection revealed that the highest prevalence was for LSIL, ASC-US, and HSIL (11.1%, 10.3%, and 6.4%, respectively). There was no difference between the abnormalities and negative cervical cytology with negative and positive C. trachomatis co-infection in HR HPV positive (p = 0.174).

Conclusion:

C. trachomatis infection was not significantly associated HR-HPV and abnormal cytology. This study confirms the increasing rate of C. trachomatis infection in asymptomatic women so routine screening for these infections has been suggested to (a) prevent complications such as the chronic pelvic pain associated with prolong infection and (b) reduce sexual transmission of the infection.

The Burden of Human Papillomavirus and Chlamydia trachomatis Coinfection in Women: A Large Cohort Study in Inner Mongolia, China

Background

Chlamydia trachomatis may coinfect with human papillomavirus (HPV) and complicate the cervical pathogenesis. This study aimed to evaluate the prevalence, risk factors, and clinical outcomes of HPV/C. trachomatis coinfection in women from Inner Mongolia, China.

Methods

We performed a polymerase chain reaction (PCR)-based HPV/C. trachomatis screening and cervical samples were analyzed by thinprep cytologic test. Statistical analysis was used to assess the association between demographic factors and coinfection.

Results

Among the 2345 women recruited, the prevalences of HPV, C. trachomatis, and HPV/C. trachomatis coinfection were 36.0%, 14.3%, and 4.8%, respectively. The rate of multiple HPV genotypes was higher in coinfected women. HPV66 was the most frequently identified genotype in coinfected participants. The HPV DNA load was significantly higher in HPV monoinfected cases. In contrast, the DNA load of C. trachomatis was significantly higher in the coinfection group. Risk factors, including single women (odds ratio [OR] = 6.0, 95% confidence interval [CI], 4.044-8.782) and women with multiple sex partners (OR = 1.9, 95% CI, 1.324-2.824), were associated with coinfection. Importantly, coinfection was associated with increased risk for high-grade squamous intraepithelial lesions.

Conclusions

HPV and C. trachomatis coinfection is an important risk factor for the progression of cervical lesions.

Comparison of analytical performances of the Roche Cobas 6800 CT/NG assay with the Abbott m2000 Real Time CT/NG assay for detecting Chlamydia trachomatis and Neisseria gonorrhoeae

The Roche Cobas 6800 CT/NG assay was compared to the Abbott m2000 Real Time CT/NG assay for detecting Chlamydia trachomatis and Neisseria gonorrhoeae in 714 specimens referred to the bacteriology laboratory at Geneva University Hospitals, between November 2017 and March 2018, and in nine external quality controls for molecular diagnostics (seven from QCMD Glasgow and two from UK NEQAS). For C. trachomatis, the sensitivity of C6800 compared to m2000 was 100 % (95 % confidence interval [CI], 97.5 to 100 %), the specificity was 99.1 % (95 % CI, 98.0 to 99.7 %). For N. gonorrhoeae, the sensitivity of the C6800 compared to m2000 was 100 % (95 % CI, 90.5 to 100 %), whereas the specificity was 99.7 % (95 % CI, 98.9 to 99.9 %). The C6800 CT/NG assay appears to perform with great accuracy the detection of C. trachomatis and N. gonorrhoeae.

Prevalence of Sexually Transmitted Infections among Married Women in Rural Nepal

Introduction

We have previously determined the prevalence of human papillomavirus (HPV) infection among women in rural Nepal. In the current study, we also wanted to examine the prevalence of and risk factors for other sexually transmitted infections (STIs) in the same population.

Methods

Population-based study of nonpregnant women ≥ 15 years who were married or had a history of marriage in the past, residing in five rural villages in Nepal. Data on sociodemographic characteristics, reproductive history, and genitourinary symptoms were collected, and a gynecological examination was conducted. Cervical samples were analyzed by real-time PCR for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis and HPV, and a serum sample was analyzed for syphilis, hepatitis B virus (HBV) and HIV infection by serology.

Results

Of 2416 eligible women, 62% participated. Trichomoniasis, Chlamydia trachomatis infection, HPV and HBV infection, and syphilis were detected in 5.4%, 0.8%, 14.3%, 0.3%, and 0.2% of the women. None had gonorrhea or HIV infection. Of those with genitourinary symptoms, 6.3% had a curable STI. Vaginal discharge classified as abnormal by gynecological examination, but not self-reported discharge, was significantly associated with laboratory diagnosis of a curable STI. Risk factors for trichomoniasis were reproductive age and high cast/ethnicity. Due to low prevalence, risk factors for other STIs could not be disclosed.

Conclusion

We observed high prevalence of HPV infection followed by trichomoniasis, while other STIs were rare among women in rural Nepal. There was no association between genitourinary symptoms and laboratory-confirmed STIs.

Anatomical site distribution and genotypes of Chlamydia trachomatis infecting asymptomatic men who have sex with men in northeast Thailand

Chlamydia trachomatis is a common agent of sexually transmitted infection, especially in asymptomatic extra-genital sites among men who have sex with men (MSM). This study aims to investigate anatomical site distribution and genotypes of C. trachomatis from asymptomatic MSM in northeast Thailand. Specimens were collected using swabs from anorectal, oropharyngeal, and urethral sites in 346 asymptomatic MSM. C. trachomatis infection was determined by real-time polymerase chain reaction and genotyping was based on sequences of the ompA gene. The results showed that infection by C. trachomatis was most common at the urethral site (29.1%, 101/346) followed by oropharyngeal (17.6%, 61/346) and anorectal site (17.0%, 59/346). In addition, C. trachomatis infection was significantly associated with absence of condom use (odds ratio = 1.909, 95%CI = 1.054-3.457, P = 0.033) at the urethral site. Overall 49.4% (171/346) of individuals were infected in at least one site. Infection at only the anorectum, oropharynx, or urethra was seen in 9.0, 9.3, and 18.5% of participants, respectively. Concurrent infections at anorectum/oropharynx, anorectum/urethra, oropharynx/urethra, and all three sites were 2.0, 4.3, 4.6, and 1.7%, respectively. Genotype D predominated at the anorectal and urethral sites among asymptomatic MSM in northeast Thailand. Concurrent infection in two or three anatomical sites occurred. C. trachomatis screening at all three sites in asymptomatic MSM is important and should be considered for proper treatment and prevention of transmission.

Impact of HPV vaccination with Gardasil® in Switzerland

BACKGROUND

Gardasil®, a quadrivalent vaccine targeting low-risk (6, 11) and high-risk (16, 18) human papillomaviruses (HPV), has been offered to 11-14 year-old schoolgirls in Switzerland since 2008. To evaluate its success and its potential impact on cervical cancer screening, HPV genotypes were examined in 18-year-old girls five years later (sub-study 1) and in outpatients participating to cervical cancer screening before and after vaccine implementation (sub-study 2).

METHODS

For sub-study 1, 3726 females aged 18 in 2013 were invited to fill a questionnaire on personal demographics and HPV risk factors and to provide a self-collected cervicovaginal sample for HPV genotyping and Chlamydia trachomatis PCR. Personal data were evaluated by univariable and multivariable statistics. In sub-study 2, the proportion of the vaccine-type HPV among anogenital HPV was examined with archived genotyping data of 8039 outpatients participating to cervical cancer screening from 1999 till 2015. The yearly evolution of this proportion was evaluated by segmented logistic regression.

RESULTS

690 (18.5%) women participated to sub-study 1 and 327 (8.8%) provided a self-collected sample. Prevalence of Chlamydia trachomatis (4.6%) and demographics confirmed that the subjects were representative of sexually-active Swiss young women. Vaccine (five-year coverage: 77.5%) was preferentially accepted by contraceptive-pill users (P = 0.001) and samples were mainly provided by sexually-active subjects (P < 0.001). The proportion (4%) of the vaccine-type HPV in this population was lower than in sub-study 2 outpatients (n = 849, <26 years old) in the pre-vaccine era (25.7%). The proportion of the high-risk vaccine-type HPV decreased significantly (59%, P = 0.0048) in the outpatients during the post-vaccine era, yet this decrease was restricted to those aged less than 26 years (n = 673, P < 0.0001).

CONCLUSIONS

The low proportion of vaccine-type HPV in 18-year-old females and its rapid decrease in young women participating to cervical cancer screening extend the success of HPV vaccination to Switzerland. Our data suggest that cervical cancer screening is now entering a stage of reduced proportion of HPV16 and/or 18 in samples reported positive by cytology. In view of the high likelihood of reduced clinical specificity of cytology, primary screening modalities involving HPV testing and cytology should now be re-evaluated in Switzerland.

Follicular Conjunctivitis due to Chlamydia felis-Case Report, Review of the Literature and Improved Molecular Diagnostics

A 29-year-old woman presented with unilateral, chronic follicular conjunctivitis since 6 weeks. While the conjunctival swab taken from the patient’s eye was negative in a Chlamydia (C.) trachomatis-specific PCR, C. felis was identified as etiological agent using a pan-Chlamydia TaqMan-PCR followed by sequence analysis. A pet kitten of the patient was found to be the source of infection, as its conjunctival and pharyngeal swabs were also positive for C. felis. The patient was successfully treated with systemic doxycycline. This report, which presents one of the few documented cases of human C. felis infection, illustrates that standard PCR tests are designed to detect the most frequently seen species of a bacterial genus but might fail to be reactive with less common species. We developed a modified pan-Chlamydia/C. felis duplex TaqMan-PCR assay that detects C. felis without the need of subsequent sequencing. The role of chlamydiae-specific serum antibody titers for the diagnosis of follicular conjunctivitis is discussed.

Multiplexed nanoplasmonic biosensor for one-step simultaneous detection of Chlamydia trachomatis and Neisseria gonorrhoeae in urine

Development of rapid and multiplexed diagnostic tools is a top priority to address the current epidemic problem of sexually transmitted diseases. Here we introduce a novel nanoplasmonic biosensor for simultaneous detection of the two most common bacterial infections: Chlamydia trachomatis and Neisseria gonorrhoeae. Our plasmonic microarray is composed of gold nanohole sensor arrays that exhibit the extraordinary optical transmission (EOT), providing highly sensitive analysis in a label-free configuration. The integration in a microfluidic system and the precise immobilization of specific antibodies on the individual sensor arrays allow for selective detection and quantification of the bacteria in real-time. We achieved outstanding sensitivities for direct immunoassay of urine samples, with a limit of detection of 300 colony forming units (CFU)/mL for C. trachomatis and 1500CFU/mL for N. gonorrhoeae. The multiplexing capability of our biosensor was demonstrated by analyzing different urine samples spiked with either C. trachomatis or N. gonorrhoeae, and also containing both bacteria. We could successfully detect, identify and quantify the levels of the two bacteria in a one-step assay, without the need for DNA extraction or amplification techniques. This work opens up new possibilities for the implementation of point-of-care biosensors that enable fast, simple and efficient diagnosis of sexually transmitted infections.

Ten years of R&D and full automation in molecular diagnosis

A 10-year experience of our automated molecular diagnostic platform that carries out 91 different real-time PCR is described. Progresses and future perspectives in molecular diagnostic microbiology are reviewed: why automation is important; how our platform was implemented; how homemade PCRs were developed; the advantages/disadvantages of homemade PCRs, including the critical aspects of troubleshooting and the need to further reduce the turnaround time for specific samples, at least for defined clinical settings such as emergencies. The future of molecular diagnosis depends on automation, and in a novel perspective, it is time now to fully acknowledge the true contribution of molecular diagnostic and to reconsider the indication for PCR, by also using these tests as first-line assays.

Prevalence of chlamydia among HIV positive and HIV negative patients in the Vhembe District as detected by real time PCR from urine samples

Background

Chlamydia is a bacterial infection that has long plagued humanity as the most commonly contracted STD and is caused by Chlamydia trachomatis. With the emergence of HIV/AIDS, sexually transmitted diseases have also re-emerged as a grave public health problem, particularly in developing countries. Updated Information about the relative frequencies in developing countries is sparse. This study aims at establishing the relative occurrence of chlamydia using real time PCR technique in the Vhembe District of South Africa where reports on the prevalence of chlamydia are not available.

Methods

A total of 243 Urine samples were collected from patients attending different ARV clinics in the Vhembe District and genomic DNA was purified using blood genomic DNA kit from Sigma-Aldrich. Real-Time PCR protocol targeting the 16S rRNA gene of C. trachomatis was used to confirm the presence of chlamydia among these patients. Demographic information as well as clinical data was collected as well.

Results

Of all the participants, 70.4 % were females. The age varied from 19 to 72 years. The overall prevalence of chlamydia was 32.1 %. The prevalence was significantly higher among females (39.2 %) compared to males (15.5 %) patients (P = 0.001) and was highest among pregnant women followed by patients who had reported any allergic reaction. Among the HIV positive patients, the prevalence was higher among those who were not taking ARV (38.1 %) compared to those who were taking them (28.5 %). The age group within which the highest prevalence was found was between 26–45 years.

Conclusions

The present study shows a high prevalence of chlamydia among HIV and AIDS patients in the Vhembe District emphasizing the need to enhance STI control and particularly chlamydia among all young people. The particularly high prevalence of chlamydia among pregnant women is of great concern as this predisposes them to complications, while allergy migh predispose people to chlamydia infections. Further studies are needed in the general population both HIV positive and HIV negative persons to further determine the impact of these infections in the community.

Rapid ultrasonic isothermal amplification of DNA with multiplexed melting analysis – applications in the clinical diagnosis of sexually transmitted diseases

We describe a nucleic acid testing (NAT) platform for infectious disease diagnostics at the point-of-care, using surface acoustic waves (SAW) to perform a multiplexed loop-mediated isothermal amplification (LAMP) test for sexually transmitted diseases. The ultrasonic actuation not only enables faster NAT reactions but also provides a route towards integrating low-cost, low-power molecular diagnostics into disposable sensors.

Improving the molecular diagnosis of Chlamydia psittaci and Chlamydia abortus infection with a species-specific duplex real-time PCR

Chlamydia psittaci and Chlamydia abortus are closely related intracellular bacteria exhibiting different tissue tropism that may cause severe but distinct infection in humans. C. psittaci causes psittacosis, a respiratory zoonotic infection transmitted by birds. C. abortus is an abortigenic agent in small ruminants, which can also colonize the human placenta and lead to foetal death and miscarriage. Infections caused by C. psittaci and C. abortus are underestimated mainly due to diagnosis difficulties resulting from their strict intracellular growth. We developed a duplex real-time PCR to detect and distinguish these two bacteria in clinical samples. The first PCR (PCR1) targeted a sequence of the 16S-23S rRNA operon allowing the detection of both C. psittaci and C. abortus. The second PCR (PCR2) targeted the coding DNA sequence CPSIT_0607 unique to C. psittaci. The two PCRs showed 100 % detection for ≥ 10 DNA copies per reaction (1000 copies ml(- 1)). Using a set of 120 samples, including bacterial reference strains, clinical specimens and infected cell culture material, we monitored 100 % sensitivity and 100 % specificity for the detection of C. psittaci and C. abortus for PCR1. When PCR1 was positive, PCR2 could discriminate C. psittaci from C. abortus with a positive predictive value of 100 % and a negative predictive value of 88 %. In conclusion, this new duplex PCR represents a low-cost and time-saving method with high-throughput potential, expected to improve the routine diagnosis of psittacosis and pregnancy complication in large-scale screening programs and also during outbreaks.

Screening for Chlamydia trachomatis in Egyptian women with unexplained infertility, comparing real-time PCR techniques to standard serology tests: case control study

BACKGROUND

To study the prevalence of Chlamydia infection in women with primary and secondary unexplained infertility using ELISA technique for antibody detection and real time, fully automated PCR for antigen detection and to explore its association with circulating antisperm antibodies (ASA).

METHODS

A total of 50 women with unexplained infertility enrolled in this case control study and a control group of 44 infertile women with a known cause of infertility. Endocervical specimens were collected for Chlamydia antigen detection using PCR and serum samples for antibodies detection. Circulating anti-sperm antibodies were detected using sperm antibody Latex Agglutination tests.

RESULTS

The overall prevalence of Chlamydial infection in unexplained infertility cases as detected by both ELISA and PCR was 40 % (20/50). The prevalence of current Chlamydial genital infection as detected by real-time PCR was only 6.0 % (3/50); two of which were also IgM positive. Prevalence of ASA was 6.0 % (3/50); all were sero-negative for anti-C.trachomatis IgM and were PCR negative.

CONCLUSION

The incidence of Chlamydial infection in Egyptian patients with unexplained infertility is relatively high. In the setting of fertility investigations; screening for anti. C.trachomatis antibodies using ELISA, and treatment of positive cases should be considered. The presence of circulating ASA does not correlate with the presence of old or current Chlamydia infection in women with unexplained infertility.

The role of the environment in transmission of Dichelobacter nodosus between ewes and their lambs

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Lambs’ feet were D. nodosus-negative at birth.

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However D. nodosus was detected on lambs’ feet within 5–13 h of birth.

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Multiple pgrA and MLVA alleles were detected on the feet of ewes and lambs.

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D. nodosus on lambs’ feet originated from sources other than just their mother's feet.

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The environment plays a key role in D. nodosus transmission between ewes and lambs.

Dichelobacter nodosus (D. nodosus) is the essential causative agent of footrot in sheep. The current study investigated when D. nodosus was detectable on newborn lambs and possible routes of transmission. Specific qPCR was used to detect and quantify the load of D. nodosus in foot swabs of lambs at birth and 5–13 h post-partum, and their mothers 5–13 h post-partum; and in samples of bedding, pasture, soil and faeces. D. nodosus was not detected on the feet of newborn lambs swabbed at birth, but was detected 5–13 h after birth, once they had stood on bedding containing naturally occurring D. nodosus. Multiple genotypes identified by cloning and sequencing a marker gene, pgrA, and by multi locus variable number tandem repeat analysis (MLVA) of community DNA from swabs on individual feet indicated a mixed population of D. nodosus was present on the feet of both ewes and lambs. There was high variation in pgrA tandem repeat number (between 3 and 21 repeats), and multiple MLVA types. The overall similarity index between the populations on ewes and lambs was 0.45, indicating moderate overlap. Mother offspring pairs shared some alleles but not all, suggesting lambs were infected from sources(s) other than just their mother's feet. We hypothesise that D. nodosus is transferred to the feet of lambs via bedding containing naturally occurring populations of D. nodosus, probably as a result of transfer from the feet of the group of housed ewes. The results support the hypothesis that the environment plays a key role in the transmission of D. nodosus between ewes and lambs.

Opportunistic testing for urogenital infection with Chlamydia trachomatis in south-western Switzerland, 2012: a feasibility study

The feasibility of opportunistic screening of urogenital infections with Chlamydia trachomatis was assessed in a cross-sectional study in 2012, in two cantons of south-western Switzerland: Vaud and Valais. Sexually active persons younger than 30 years, not tested for C. trachomatis in the last three months, were invited for free C. trachomatis testing by PCR in urine or self-applied vaginal swabs. Of 2,461 consenting participants, 1,899 (77%) were women and all but six (0.3%) submitted a sample. Forty-seven per cent of female and 25% of male participants were younger than 20 years. Overall, 134 (5.5%) of 2,455 tested participants had a positive result and were followed up. Seven per cent of all candidates for screening were not invited, 10% of invited candidates were not eligible, 15% of the eligible candidates declined participation, 5% of tested participants testing positive were not treated, 29% of those treated were not retested after six months and 9% of those retested were positive for C. trachomatis. Opportunistic C. trachomatis testing proved technically feasible and acceptable, at least if free of charge. Men and peripheral rural regions were more difficult to reach. Efforts to increase testing and decrease dropout at all stages of the screening procedure are necessary.

Roles of bovine Waddlia chondrophila and Chlamydia trachomatis in human preterm birth

Waddlia chondrophila and Chlamydia trachomatis are intracellular bacteria associated with human miscarriage. We investigated their role in human preterm birth. Whereas presence of Chlamydia trachomatis DNA in genital tract was associated with human preterm birth, Waddlia was not, despite being present in women's genital tracts.

Chlamydia trachomatis infection among female inmates at Briman prison in Saudi Arabia

BACKGROUND

Chlamydia trachomatis infection is the most common sexually transmitted infection (STI) in the western countries; its prevalence in the conservative Muslim population of Saudi Arabia is not known, but it is generally believed to be low. This study is the first to investigate the prevalence of and risk factors for C. trachomatis infection in the high-risk group of female inmates at Briman Prison in Jeddah.

METHODS

The inmates were interviewed using a pre-designed questionnaire, and their urine samples were tested for C. trachomatis infection by real-time PCR assay.

RESULTS

The overall prevalence of C. trachomatis infection was 8.7% in the study population. The ≤25 age group was predominantly affected, with an average prevalence of 16.6%. Two out of five (2/5, 40%) Yamani, (4/33 12.1%) Indonesian, (3/33, 9.1%) Somalian and (2/26, 7.7%) Ethiopian inmates were positive for infection. None of the Saudi inmates (0/14) were positive for infection. Among the studied variables, only age was significantly associated with the infection rate. The other variables (marital status, nationality, religion, employment status, education level, nature of the offense committed, knowledge about protection from STIs, and knowledge about condom use and the purpose of condom use) did not show a significant correlation with Chlamydia infection.

CONCLUSIONS

The overall prevalence of C. trachomatis infection was within the range published by other reports in similar prison settings in developed countries. The results indicate the need for a countrywide screening and treatment program for all inmates at the time of entry into prison.

Chlamydia trachomatis infection in HIV-infected women: need for screening by a sensitive and specific test

Reproductive tract infection (RTIs)/sexually transmitted infections (STIs) are recognized as a major public health problem, particularly due to their relationship with HIV infection. Early detection and treatment of Chlamydia trachomatis infection (CTI) among HIV-infected and HIV-uninfected women may impact heterosexual HIV transmission. A total of 120 participants were enrolled: 30 HIV seropositive women with symptoms of RTIs, 30 HIV seropositive women without symptoms of RTIs, 30 HIV seronegative women with symptoms of RTIs, and 30 HIV seronegative women without symptoms of RTIs. One endocervical swab was collected from all participants and CTI was detected by real-time PCR (COBAS TaqMan CT Test, v2.0). CTI was detected in 4 (6.67%) HIV-infected women and in 1 (1.67%) HIV-uninfected woman (OR 4.214; 95% CI 0.457–38.865). Vaginal discharge was present in almost half of HIV-infected and HIV-uninfected women; lower abdominal pain was present in 11 (18.3%) of HIV-infected and in 9 (15%) of HIV-uninfected women. This study showed that CTI is more prevalent among HIV-infected females as compared to HIV-uninfected females. As the use of real-time PCR is not feasible in most hospitals, efforts should be made to develop a simple, sensitive, and specific test to identify women with CTI for prevention of sequelae and HIV transmission.

Evaluation of a real-time PCR test for the detection and discrimination of theileria species in the African buffalo (Syncerus caffer)

A quantitative real-time PCR (qPCR) assay based on the cox III gene was evaluated for the simultaneous detection and discrimination of Theileria species in buffalo and cattle blood samples from South Africa and Mozambique using melting curve analysis. The results obtained were compared to those of the reverse line blot (RLB) hybridization assay for the simultaneous detection and differentiation of Theileria spp. in mixed infections, and to the 18S rRNA qPCR assay results for the specific detection of Theileria parva.

Theileria parva, Theileria sp. (buffalo), Theileria taurotragi, Theileria buffeli and Theileria mutans were detected by the cox III assay. Theileria velifera was not detected from any of the samples analysed. Seventeen percent of the samples had non-species specific melting peaks and 4.5% of the samples were negative or below the detection limit of the assay. The cox III assay identified more T. parva and Theileria sp. (buffalo) positive samples than the RLB assay, and also detected more T. parva infections than the 18S assay. However, only a small number of samples were positive for the benign Theileria spp. To our knowledge T. taurotragi has never been identified from the African buffalo, its identification in some samples by the qPCR assay was unexpected.

Because of these discrepancies in the results, cox III qPCR products were cloned and sequenced. Sequence analysis indicated extensive inter- and intra-species variations in the probe target regions of the cox III gene sequences of the benign Theileria spp. and therefore explains their low detection. The cox III assay is specific for the detection of T. parva infections in cattle and buffalo. Sequence data generated from this study can be used for the development of a more inclusive assay for detection and differentiation of all variants of the mildly pathogenic and benign Theileria spp. of buffalo and cattle.

Development of a high throughput PCR to detect Coxiella burnetii and its application in a diagnostic laboratory over a 7-year period

Q fever is a worldwide zoonotic infectious disease due to Coxiella burnetii. The clinical presentation may be acute (pneumonia and/or hepatitis) or chronic (most commonly endocarditis). Diagnosis mainly relies on serology and PCR. We therefore developed a quantitative real-time PCR. We first tested blindly its performance on various clinical samples and then, when thoroughly validated, we applied it during a 7-year period for the diagnosis of both acute and persistent C. burnetii infection. Analytical sensitivity (< 10 copies/PCR) was excellent. When tested blindly on 183 samples, the specificity of the PCR was 100% (142/142) and the sensitivity was 71% (29/41). The sensitivity was 88% (7/8) on valvular samples, 69% (20/29) on blood samples and 50% (2/4) on urine samples. This new quantitative PCR was then successfully applied for the diagnosis of acute Q fever and endovascular infection due to C. burnetii, allowing the diagnosis of Q fever in six patients over a 7-year period. During a local small cluster of cases, the PCR was also applied to blood from 1355 blood donors; all were negative confirming the high specificity of this test. In conclusion, we developed a highly specific method with excellent sensitivity, which may be used on sera for the diagnosis of acute Q fever and on various samples such as sera, valvular samples, aortic specimens, bone and liver, for the diagnosis of persistent C. burnetii infection.

Chronic prostatitis does not influence urinary PCA3 score

BACKGROUND

The influence of chronic prostatitis on serum PSA level is well known. Whether it also influences potential new biomarkers of prostate cancer (PCa) has to be determined. We conducted a prospective study to evaluate the effect of chronic prostatitis on the PCa urinary marker PCA3.

METHODS

Included were 38 patients, mean-aged of 37.5 years, with clinical suspicion of chronic prostatitis. A simplified version of the Meares-Stamey four-glass localization test was performed and urine specimens were collected for cytological analysis and culture. A postprostatic massage urine sample was used for the urinary PCA3 test.

RESULTS

Four patients had an eventual diagnosis of urethritis and all had a PCA3 score less than 5. Among the remaining 34 patients, 7 had bacterial chronic prostatitis (NIH II prostatitis), 11 had abacterial chronic prostatitis (NIH IIIa), and 16 had non inflammatory prostatodynia (NIH IIIb). All these patients had a PCA3 score less than 28, that is, under the cutoff of 35, which is commonly used for prostate cancer diagnosis. Patients with NIH category IIIa prostatitis had significantly higher number of leukocytes and red cells as well as prostate cells in urine samples but their PCA3 scores did not differ from those of other prostatitis patients.

CONCLUSION

In this study, NIH II and III chronic prostatitis did not influence the PCA3 score. Our results suggest that increased PCA3 score is unlikely to be explained by the sole chronic prostatitis and warrants prostate biopsies to eliminate prostate cancer.

Role of Chlamydia trachomatis in miscarriage

To determine the role of Chlamydia trachomatis in miscarriage, we prospectively collected serum, cervicovaginal swab specimens, and placental samples from 386 women with and without miscarriage. Prevalence of immunoglobulin G against C. trachomatis was higher in the miscarriage group than in the control group (15.2% vs. 7.3%; p = 0.018). Association between C. trachomatis-positive serologic results and miscarriage remained significant after adjustment for age, origin, education, and number of sex partners (odds ratio 2.3, 95% confidence interval 1.1-4.9). C. trachomatis DNA was more frequently amplified from products of conception or placenta from women who had a miscarriage (4%) than from controls (0.7%; p = 0.026). Immunohistochemical analysis confirmed C. trachomatis in placenta from 5 of 7 patients with positive PCR results, whereas results of immunohistochemical analysis were negative in placenta samples from all 8 negative controls tested. Associations between miscarriage and serologic/molecular evidence of C. trachomatis infection support its role in miscarriage.

Amoebal host range, host-free survival and disinfection susceptibility of environmental Chlamydiae as compared to Chlamydia trachomatis

The term 'Chlamydia-like organisms' encompasses obligate intracellular bacterial species phylogenetically close to Chlamydiaceae. Most are associated with free-living amoebae, and several could be responsible for respiratory tract infections and abortion in human and animals. Despite increasing concern about their pathogenic role, the prevalence, biodiversity and ecology of Chlamydia-related bacteria still remain largely unknown. In this study, six members of the Chlamydiales were tested, including Parachlamydia acanthamoebae (two different strains), Protochlamydia naegleriophila, Waddlia chondrophila, Criblamydia sequanensis and Chlamydia trachomatis as a reference. Intracellular growth was tested in 11 different Acanthamoeba strains, demonstrating significant differences in host susceptibilities to infection depending on strains investigated. Survival of host-free bacteria in suspension or dried onto surfaces was also explored, demonstrating that Chlamydia-like organisms present better survival capacity than C. trachomatis. Longer survival times were observed for bacteria suspended in rich culture medium, with survivors being detected after 10 weeks incubation. We also tested susceptibility of host-free Chlamydia-like organisms to several disinfection treatments. Each chemical biocide tested reduced viability of host-free Chlamydia by more than 4 logs. Conversely, all Chlamydia-like organisms tested resisted exposure at 55 °C for 10 min, while C. trachomatis was completely inactivated.

Development of a new chlamydiales-specific real-time PCR and its application to respiratory clinical samples

Originally composed of the single family Chlamydiaceae, the Chlamydiales order has extended considerably over the last several decades. Chlamydia-related bacteria were added and classified into six different families and family-level lineages: the Criblamydiaceae, Parachlamydiaceae, Piscichlamydiaceae, Rhabdochlamydiaceae, Simkaniaceae, and Waddliaceae. While several members of the Chlamydiaceae family are known pathogens, recent studies showed diverse associations of Chlamydia-related bacteria with human and animal infections. Some of these latter bacteria might be of medical importance since, given their ability to replicate in free-living amoebae, they may also replicate efficiently in other phagocytic cells, including cells of the innate immune system. Thus, a new Chlamydiales-specific real-time PCR targeting the conserved 16S rRNA gene was developed. This new molecular tool can detect at least five DNA copies and show very high specificity without cross-amplification from other bacterial clade DNA. The new PCR was validated with 128 clinical samples positive or negative for Chlamydia trachomatis or C. pneumoniae. Of 65 positive samples, 61 (93.8%) were found to be positive with the new PCR. The four discordant samples, retested with the original test, were determined to be negative or below detection limits. Then, the new PCR was applied to 422 nasopharyngeal swabs taken from children with or without pneumonia; a total of 48 (11.4%) samples were determined to be positive, and 45 of these were successfully sequenced. The majority of the sequences corresponded to Chlamydia-related bacteria and especially to members of the Parachlamydiaceae family.

Chlamydiales and the innate immune response: friend or foe?

Pathogenicity of Chlamydia and Chlamydia-related bacteria could be partially mediated by an enhanced activation of the innate immune response. The study of this host pathogen interaction has proved challenging due to the restricted in vitro growth of these strict intracellular bacteria and the lack of genetic tools to manipulate their genomes. Despite these difficulties, the interactions of Chlamydiales with the innate immune cells and their effectors have been studied thoroughly. This review aims to point out the role of pattern recognition receptors and signal molecules (cytokines, reactive oxygen species) of the innate immune response in the pathogenesis of chlamydial infection. Besides inducing clearance of the bacteria, some of these effectors may be used by the Chlamydia to establish chronic infections or to spread. Thus, the induced innate immune response seems to be variable depending on the species and/or the serovar, making the pattern more complex. It remains crucial to determine the common players of the innate immune response in order to help define new treatment strategies and to develop effective vaccines. The excellent growth in phagocytic cells of some Chlamydia-related organisms such as Waddlia chondrophila supports their use as model organisms to study conserved features important for interactions between the innate immunity and Chlamydia.

Routine use of point-of-care tests: usefulness and application in clinical microbiology

Point-of-care (POC) tests offer potentially substantial benefits for the management of infectious diseases, mainly by shortening the time to result and by making the test available at the bedside or at remote care centres. Commercial POC tests are already widely available for the diagnosis of bacterial and viral infections and for parasitic diseases, including malaria. Infectious diseases specialists and clinical microbiologists should be aware of the indications and limitations of each rapid test, so that they can use them appropriately and correctly interpret their results. The clinical applications and performance of the most relevant and commonly used POC tests are reviewed. Some of these tests exhibit insufficient sensitivity, and should therefore be coupled to confirmatory tests when the results are negative (e.g. Streptococcus pyogenes rapid antigen detection test), whereas the results of others need to be confirmed when positive (e.g. malaria). New molecular-based tests exhibit better sensitivity and specificity than former immunochromatographic assays (e.g. Streptococcus agalactiae detection). In the coming years, further evolution of POC tests may lead to new diagnostic approaches, such as panel testing, targeting not just a single pathogen, but all possible agents suspected in a specific clinical setting. To reach this goal, the development of serology-based and/or molecular-based microarrays/multiplexed tests will be needed. The availability of modern technology and new microfluidic devices will provide clinical microbiologists with the opportunity to be back at the bedside, proposing a large variety of POC tests that will allow quicker diagnosis and improved patient care.

New Diagnostic Real-Time PCR for Specific Detection of Mycoplasma hominis DNA

Mycoplasma hominis is a fastidious micro-organism causing genital and extragenital infections. We developed a specific real-time PCR that exhibits high sensitivity and low intrarun and interrun variabilities. When applied to clinical samples, this quantitative PCR allowed to confirm the role of M. hominis in three patients with severe extragenital infections.

Development of a real-time PCR for the specific detection of Waddlia chondrophila in clinical samples

Waddlia chondrophila is considered as an emerging human pathogen likely involved in miscarriage and lower respiratory tract infections. Given the low sensitivity of cell culture to recover such an obligate intracellular bacteria, molecular-based diagnostic approaches are warranted. We thus developed a real-time PCR that amplifies Waddlia chondrophila DNA. Specific primers and probe were selected to target the 16S rRNA gene. The PCR specifically amplified W. chondrophila but did not amplify other related-bacteria such as Parachlamydia acanthamoebae, Simkania negevensis and Chlamydia pneumoniae. The PCR exhibited a good intra-run and inter-run reproducibility and a sensitivity of less than ten copies of the positive control. This real-time PCR was then applied to 32 nasopharyngeal aspirates taken from children with bronchiolitis not due to respiratory syncytial virus (RSV). Three samples revealed to be Waddlia positive, suggesting a possible role of this Chlamydia-related bacteria in this setting.

Rapid detection of Chlamydia trachomatis and typing of the Lymphogranuloma venereum associated L-Serovars by TaqMan PCR

Background

Infection due to Chlamydia trachomatis is the most common sexually transmitted bacterial disease of global health significance, and especially the L-serovars causing lymphogranuloma venereum are increasingly being found in Europe in men who have sex with men.

Results

The design and evaluation of a rapid, multiplex, real-time PCR targeting the major outer membrane protein (omp-1) -gene and a L-serovar-specific region of the polymorphic protein H (pmp-H) -gene for the detection of Chlamydia trachomatis is reported here. The PCR takes place as a single reaction with an internal control. For L1-, L2- and L3-serovar differentiation a second set of real-time PCRs was evaluated based on the amplification of serovar-specific omp-1-regions. The detection limit of each real-time PCR, multiplexed or not, was 50 genome copies per reaction with an efficiency ranging from 90,5–95,2%.

In a retrospective analysis of 50 ocular, rectal and urogenital specimens formerly tested to be positive for C. trachomatis we identified six L2-serovars in rectal specimens of HIV-positive men, one in a double-infection with L3, and one L2 in a urethral specimen of an HIV-negative male.

Conclusion

This unique real-time PCR is specific and convenient for the rapid routine-diagnostic detection of lymphogranuloma venereum-associated L-serovars and enables the subsequent differentiation of L1, L2 and L3 for epidemiologic studies.

Low prevalence of Chlamydia trachomatis infection in asymptomatic young Swiss men

Background

Prevalence and risk factors for Chlamydia trachomatis infection among young men in Switzerland is still unknown. The objective of the present study was to assess prevalence and risk factors for C. trachomatis infection in young Swiss men.

Methods

517 young Swiss men were enrolled in this cross-sectional study during their compulsory military recruitment. Participants completed a questionnaire and gave urine samples which were screened for C. trachomatis DNA by PCR. Genotyping of positive samples was done by amplification and sequencing the ompA gene.

Results

The prevalence of chlamydial infection among young Swiss male was 1.2% (95% confidence interval [95%CI], 0.4–2.5%). C. trachomatis infection was only identified among the 306 men having multiple sexual partner. Although frequent, neither unprotected sex (absence of condom use), nor alcohol and drug abuse were associated with chlamydial infection. Men living in cities were more frequently infected (2.9%, 95%CI 0.8–7.4%) than men living in rural areas (0.5%, 95%CI 0.1–1.9%, p = 0.046). Moreover, naturalised Swiss citizens were more often positive (4.9%, 95%CI 1.3–12.5%) than native-born Swiss men (0.5%, 95%CI 0.1–1.7%, p = 0.003).

Conclusion

In comparison with other countries, the prevalence of chlamydial infection in men is extremely low in Switzerland, despite a significant prevalence of risky sexual behaviour. C. trachomatis infection was especially prevalent in men with multiple sexual partners. Further research is required (i) to define which subgroup of the general population should be routinely screened, and (ii) to test whether such a targeted screening strategy will be effective to reduce the prevalence of chlamydial infection among this population.

Emerging role of Chlamydia and Chlamydia-like organisms in adverse pregnancy outcomes

PURPOSE OF THE REVIEW

This review considers the roles of Chlamydia spp. and newly identified Chlamydia-like organisms in miscarriage, stillbirths and preterm labour in both animals and humans.

RECENT FINDINGS

The cause of miscarriage, stillbirth and preterm labour often remains unexplained. Intracellular bacteria that grow either poorly or not at all on media used routinely to detect human pathogens could be the aetiological agents of these obstetrical conditions. There is growing evidence that Chlamydia trachomatis, Chlamydophila abortus, Chlamydophila psittaci and Chlamydophila pneumoniae infections may result in adverse pregnancy outcomes in humans and/or animals. Waddlia, a Chlamydia-like organism first isolated from an aborted bovine, has emerged as an agent of abortion in cattle. Recently, Waddlia was also implicated in human foetal death. Moreover, Parachlamydia acanthamoebae is also abortigenic in ruminants. Whether additional novel Chlamydia-like organisms, such as Protochlamydia amoebophila, Neochlamydia hartmanellae, Criblamydia sequanensis, Rhabdochlamydia crassificans and Simkania negevensis, are involved in foetal loss or premature delivery remains to be determined.

SUMMARY

This review provides an update on the consequences of chlamydial infection during pregnancy and summarizes current evidence suggesting that some Chlamydia-related organisms are probably emerging obstetrical pathogens.

Protochlamydia naegleriophila as etiologic agent of pneumonia

Using ameba coculture, we grew a Naegleria endosymbiont. Phenotypic, genetic, and phylogenetic analyses supported its affiliation as Protochlamydianaegleriophila sp. nov. We then developed a specific diagnostic PCR for Protochlamydia spp. When applied to bronchoalveolar lavages, results of this PCR were positive for 1 patient with pneumonia. Further studies are needed to assess the role of Protochlamydia spp. in pneumonia.