Molecular diagnosis of lymphogranuloma venereum in patients with genital ulcer disease

Differential expression of groEL-1, incB, pyk-F, tal, hctA and omcB genes during Chlamydia trachomatis developmental cycle

Chlamydia trachomatis infects squamous and columnar epithelia at the mucosal surface. Research on gene expression patterns of C. trachomatis has predominantly focused on non-native host cells, with limited data on growth kinetics and gene expression of chlamydia in keratinocytes. Here, we investigated whether early, mid, and late chlamydial genes observed in HeLa cell line studies were co-ordinately regulated at the transcriptional level even in the keratinized cell line model and whether the expression was stage-specific during the developmental cycle. HaCaT cell lines were infected with chlamydia clinical isolates (US151and serovar E) and reference strain (L2 434). Expression of groEL-1, incB, pyk-F, tal, hctA, and omcB genes was conducted with comparative real-time PCR and transcriptional events during the chlamydial developmental cycle using transmission electron microscopy. The relative expression level of each gene and fold difference were calculated using the 2-ΔΔCT method. The expression of groEL-1 and pyk-F genes was highest at 2 hours post-infection (hpi) in the L2 434 and serovar E. The expression of incB gene increased at 2 hpi in L2 434 and serovar E but peaked at 12 hpi in serovar E. L2 434 and US151 had similar tal expression profiles. Increased expression of hctA and omcB genes were found at 2 and 36 hpi in L2 434. Both clinical isolates and reference strains presented the normal chlamydial replication cycle comprising elementary bodies and reticulate bodies within 36 hpi. We show different gene expression patterns between clinical isolates and reference strain during in vitro infection of keratinocytes, with reference strain-inducing consistent expression of genes. These findings confirm that keratinocytes are appropriate cell lines to interrogate cell differentiation, growth kinetics, and gene expression of C. trachomatis infection. Furthermore, more studies with different clinical isolates and genes are needed to better understand the Chlamydial pathogenesis in keratinocytes.

Etiology of Genital Ulcer Disease in Male Patients Attending a Sexually Transmitted Diseases Clinic: First Assessment in Cuba

BACKGROUND

Sexually transmitted diseases (STDs) and in particular genital ulcer disease (GUD) have a major impact on morbidity and mortality in developing countries. The World Health Organization recommends the use of syndromic guidelines for the treatment of sexually transmitted infections (STIs) in resource-constrained countries. Surveillance of autochthonous etiologies provides epidemiological information contributing to the prevention and treatment of STIs. We investigated the etiology and factors associated with GUD among male patients attending a STD clinic in Havana, Cuba.

METHODS

Swabs from genital ulcers of 113 male patients, collected from May 2012 to June 2015, were analyzed using PCR for herpes simplex virus types 1 and 2, Treponema pallidum, Haemophilus ducreyi, and Chlamydia trachomatis. We also investigated the clinical and epidemiological characteristics associated with the presence of these pathogens in GUD.

RESULTS

At least one of the pathogens was detected in 70% of patients. The occurrence of the pathogens was herpes simplex virus type 2 (HSV-2) (51.3%), T. pallidum (29.2%), and C. trachomatis (1.8%). Co-infections occurred as follows: T. pallidum-HSV-2 (10.6%), C. trachomatis-HSV-2 (0.9%) and C. trachomatis-T. pallidum (0.9%). Herpes simplex virus type 1 and H. ducreyi were not detected. Ages 15 to 40 years, HIV-positive serostatus, and no condom use were significant risk factors for the presence of HSV-2 in genital ulcers.

CONCLUSIONS

Our preliminary results highlight the predominance of HSV-2 and T. pallidum as the leading GUD etiologies in the study population and identified risk factors associated with HSV-2. This information should help to inform guidelines for better management of GUD in Havana, Cuba.

Overview of molecular biological methods for the detection of pathogens causing sexually transmitted infections

We review here different state-of-the-art molecular methods currently used in the diagnosis of sexually transmitted infections.

Evaluation of a novel Chlamydia trachomatis microsphere suspension assay for detection and genotyping of the different serovars in clinical samples

A novel Chlamydia trachomatis (Ct) microsphere suspension (MS) assay was evaluated for identification of the different serovars, using the same PCR primer set established for the Ct Detection and genoTyping assay. Both assays can detect and identify all 14 major serovars (A, B/Ba, C, D/Da, E, F, G/Ga, H, I/Ia, J, K, L1, L2/L2a, and L3) and one genovariant of serovar J. The probe specificity for the Ct-MS assay was determined using 14 Ct reference strains and 1 clinical isolate from a genovariant of serovar J. Also, the Ct-MS assay and the Ct detection and genoTyping assay were compared in 712 Ct-positive clinical samples. The Ct-MS assay showed a highly specific reaction for all probes with the amplicons of the reference strains, giving a very low background median fluorescence intensity signal (median fluorescence intensity ≤ 10). An excellent overall agreement in the Ct detection (kappa = 0.947, 95% confidence interval, 0.89 to 0.999; McNemar's test, P = 1.000) and the Ct genotyping (kappa = 0.993, 95% confidence interval, 0.977 to 1.000; McNemar's test, P = 0.053) was observed between the Ct detection and genoTyping (DT) assay and the Ct-MS assay. In conclusion, the novel Ct-MS assay permits simultaneous detection and genotyping of Ct serovars, making the Ct-MS assay an excellent high throughput method.

Differences in Chlamydia trachomatis growth rates in human keratinocytes among lymphogranuloma venereum reference strains and clinical isolates

The pathogenesis of the primary stage of lymphogranuloma venereum (LGV) is poorly understood. There is no skin cell model and LGV pathogenesis studies are therefore carried out on cells of different origin. Moreover, such studies usually use reference strains, which may have evolved over the years in culture. In this study, a model was developed in which Chlamydia trachomatis enters and grows in human keratinocytes at 37 and 33 °C. Keratinocytes were infected with fresh clinical isolates and the three LGV reference strains L1, L2 and L3. Growth was monitored for 5 days post-infection using fluorescence microscopy and image analysis software. Chlamydial replication was quicker at 37 than at 33 °C, despite 33 °C being the temperature of human skin. The serovar L2 reference strain grew significantly faster than the other strains, although the fresh clinical isolates were also serovar L2. When grown in keratinocytes at 33 °C, the L2 and L3 reference strains produced much larger inclusions than the other strains tested. This model, which utilizes keratinocytes, better simulates the conditions present at the initial site of infection in LGV than previously published literature, making it a useful tool for future LGV pathogenesis studies. In addition, the results indicate that fresh clinical isolates should be included in LGV pathogenesis studies.

Manifestations and management of lymphogranuloma venereum

PURPOSE OF REVIEW

This review was prompted by a sustained outbreak of lymphogranuloma venereum that has been observed among men who have sex with men (MSM) worldwide since 2004. Recent developments in the epidemiology, diagnosis and management of the infection are summarized.

RECENT FINDINGS

Between the early 1980s and 2003, lymphogranuloma venereum was rarely seen in the developed world. In 2003, a cluster of cases was seen in the Netherlands occurring mostly in HIV-positive MSM with high levels of sexual risk. With the assistance of novel molecular diagnostic techniques, more than a thousand cases of Chlamydia trachomatis L2 serovar disease have now been reported in MSM worldwide. Almost all have presented with rectal infection, usually manifesting as severe proctitis, with ulcer adenopathy syndrome seldom seen. Oral doxycycline remains the recommended treatment and has proven effective in the recent outbreak. Conflicting data exist regarding the prevalence of asymptomatic infection, and our understanding of the exact modes of transmission remains incomplete.

SUMMARY

Lymphogranuloma venereum appears to have reestablished endemicity among MSM populations in many industrialized nations. In the relative absence of recent publications from its traditional endemic regions it can be assumed that these populations remain afflicted by the infection as well.

Lymphogranuloma venereum prevalence in Sweden among men who have sex with men and characterization of Chlamydia trachomatis ompA genotypes

An outbreak of lymphogranuloma venereum (LGV) infections has recently been reported from The Netherlands and other European countries. The Swedish surveillance system has identified three LGV cases since 2004, all with clinically suspected infection in men who have sex with men (MSM). In order to assess the prevalence of LGV in a high-risk group of MSM and include clinically atypical cases, retrospective analysis of 197 Chlamydia trachomatis-infected men was performed. Sequencing of the ompA gene showed a different serotype distribution compared to recent Swedish studies in heterosexual populations. The most common types were G (45%), D (27%), and J (26%), whereas the normally predominant type E accounted for only 4% of the chlamydia cases. Furthermore, certain ompA genotype variants of the dominant serotypes were highly prevalent among MSM, and the reason for this is discussed. No additional case of LGV was detected by retrospective analysis of the high-risk MSM population. This indicates that, thus far, LGV in Sweden is only a result of sporadic import from infected MSM clusters abroad.

A multiplexed real-time PCR assay for rapid detection of Chlamydia trachomatis and identification of serovar L-2, the major cause of Lymphogranuloma venereum in New York

Lymphogranuloma venereum (LGV) is caused by a rare form of Chlamydia trachomatis that is difficult to diagnose, since culture is not readily available, and since other methods are not reliable or lack sensitivity. We report here a rapid, sensitive, and specific real-time multiplex polymerase chain reaction (PCR) assay capable of detecting C. trachomatis and identifying serovar L-2 in the same reaction, directly from rectal swabs. The analytical sensitivity of the assay was 25 genome copies for C. trachomatis, and 50 genome copies for L-2. The analytical specificity was 100%, as demonstrated with a diverse range of C. trachomatis serovars and other site-specific bacterial pathogens. With the use of a rapid DNA extraction method, a blinded validation of spiked rectal swabs correctly identified 30 samples containing C. trachomatis cells, L-2 DNA, or negative samples. The multiplexed PCR assay also identified serovar L-2 in 13 of 70 rectal swab samples taken from symptomatic patients. Twelve additional samples were positive for C. trachomatis only, and omp1 sequencing determined these samples as either serovar D, E, G, J, or K. This assay represents the first real-time PCR method capable of detecting C. trachomatis DNA, and of simultaneously identifying C. trachomatis infection as serovar L-2.