Optimised sample preparation of synovial fluid for detection of Chlamydia trachomatis DNA by polymerase chain reaction

Rapid Diagnostic of Streptococcus suis in Necropsy Samples of Pigs by thrA-Based Loop-Mediated Isothermal Amplification Assay

Streptococcus (S.) suis presents a serious threat to the pig industry as well as food safety and public health. Although several LAMP assays have been developed for the identification of S. suis, no universal assay is so far available for the field-suitable examination of clinical pig specimens. Based on the thrA housekeeping gene, a new loop-mediated isothermal amplification (LAMP) assay was developed and validated for the detection of S. suis in the brain and joints of pigs. For this LAMP assay, two different methods for the extraction of DNA from brain and joint swabs were compared. Using the LPTV boiling method, the detection limit of LAMP was 1.08 CFU/reaction, while the detection limit was 53.8 CFU/reaction using a commercial DNA extraction kit. The detection limits of thrA-LAMP in combination with the LPTV boiling method were 104-105 CFU/swab in the presence of brain tissue and 103-104 CFU/swab in the presence of joint tissue. The diagnostic quality criteria of LAMP were determined by the examination of 49 brain swabs and 34 joint swabs obtained during routine diagnostic necropsies. Applying the LPTV boiling method to brain swabs, the sensitivity, specificity, and positive and negative predictive values of thrA-LAMP were 88.0, 95.8, 95.7, and 88.5% using cultural investigation as a reference method, and 76.7, 100, 100, and 73.1% using real-time PCR as a reference method. Based on these results, the thrA-LAMP assay combined with the LPTV boiling method is suitable for rapid detection of S. suis from brain swabs.

A broad-range PCR technique for the diagnosis of infective endocarditis

Infective endocarditis (IE) remains a severe and potentially fatal disease demanding sophisticated diagnostic strategies for detection of the causative microorganisms. The aim of the present study was to develop a broad-range 16S ribosomal RNA gene polymerase chain reaction in the routine diagnostic of IE for the early diagnosis of fatal disease. A broad-range PCR technique was selected and evaluated in terms of its efficiency in the diagnosis of endocarditis using 19 heart valves from patients undergoing cardiovascular surgeries at the Habib Bourguiba Hospital of Sfax, Tunisia, on the grounds of suspected IE. The results demonstrated the efficiency of this technique particularly in cases involving a limited number of bacteria since it helped to increase detection sensitivity. The technique proved to be efficient, particularly, in the bacteriological diagnosis of IE in contexts involving negative results from conventional culture methods and other contexts involving bacterial species that were not amenable to identification by phenotypic investigations. Indeed, the sequencing of the partial 16S ribosomal RNA gene revealed the presence of Bartonella henselae, Enterobacter sp., and Streptococcus pyogenes in three heart valves with the negative culture. It should be noted that the results obtained from the polymerase chain reaction-sequencing identification applied to the heart valve and the strain isolated from the same tissue were not consistent with the ones found by the conventional microbiological methods in the case of IE caused by Gemella morbillorum. In fact, the results from the molecular identification revealed the presence of Lactobacillus jensenii. Overall, the results have revealed that the proposed method is sensitive, reliable and might open promising opportunities for the early diagnosis of IE.

Coinfection of Chlamydiae and other Bacteria in Reactive Arthritis and Spondyloarthritis: Need for Future Research

Reactive (inflammatory) arthritis has been known for many years to follow genital infection with the intracellular bacterial pathogen Chlamydia trachomatis in some individuals. Recent studies from several groups have demonstrated that a related bacterium, the respiratory pathogen Chlamydia pneumoniae, can elicit a similar arthritis. Studies of these organisms, and of a set of gastrointestinal pathogens also associated with engendering inflammatory arthritis, have been relatively extensive. However, reports focusing on coinfections with these and/or other organisms, and the effects of such coinfections on the host immune and other systems, have been rare. In this article, we review the extant data regarding infections by multiple pathogens in the joint as they relate to engendering arthritis, and we suggest a number of research areas that must be given a high priority if we are to understand, and therefore to treat in an effective manner, such arthritides.

Optimized testing for C. trachomatis DNA in synovial fluid samples in clinical practice

AIM

No standardized polymerase chain reaction (PCR) assay is available for detection of Chlamydia trachomatis (C. tr.) in synovial fluid (SF) for diagnostic use in clinical practice. This study tested the performance of two optimized molecular biology methods, to determine which is best suited for detecting C. tr. in SF clinical samples from patients with various rheumatologic diseases.

METHODS

Two DNA extraction methods, i.e., (1) alkaline lysis and (2) QIAEX II Gel Extraction Kit® + cetyltrimethylammonium bromide (CTAB; Qiagen, Hilden, Germany), and C. tr.-omp1-152 bp PCR were tested in SF samples from a total of 329 patients with the following diagnoses: reactive arthritis (ReA; n = 10, 4 patients had posturethritic ReA), undifferentiated arthritis (UA; n = 66), rheumatoid arthritis (RA; n = 169), psoriatic arthritis (PSA; n = 12), and osteoarthritis (OA) n = 72.

RESULTS

In SF samples, C. tr.-omp1-152 bp PCR in combination with alkaline lysis DNA extraction allowed detection of more C. tr.-positive samples: 3/10 (30%) ReA patients (all with posturethritic ReA) and 20/66 (38%) UA patients were positive, compared to the 0/10 (0%) patients with ReA and 1/66 (2%) with UA detected using the QIAEX II Gel Extraction Kit® + CTAB. Moreover, 2/12 (17%) SF samples from PSA patients tested positive with alkaline lysis. All samples from patients with OA and RA tested negative.

CONCLUSION

Alkaline lysis in combination with C. tr.-omp1-152 bp PCR emerged as the most sensitive method for identification of C. tr. in clinical SF samples.

Validation of a previously developed quantitative polymerase chain reaction for the detection and quantification of Mycoplasma synoviae in chicken joint specimens

A quantitative polymerase chain reaction (qPCR) was validated for the detection of Mycoplasma synoviae (PCR equivalents of colony-forming units [CFU eq.]) in chicken joint specimens with time and compared with direct mycoplasma culture. Joint specimens were obtained from 70 layer pullets inoculated intravenously with M. synoviae at 6 weeks of age. Ten control birds were injected intra-articularly with Freund's complete adjuvant. Macroscopic joint lesions were observed in 54 infected birds, of which 11 showed positive M. synoviae culture. The specificity of direct mycoplasma culture was high (100%, 95% confidence interval [CI] = 74 to 100), but its sensitivity low (16%, 95% CI = 8 to 26). Most positive results were obtained during the first 2 weeks after onset of joint swelling using synovial fluid. The qPCR was positive in 26 of 28 synovial fluid samples and in 51 of 70 joint swabs. The sterile joint samples obtained from Freund's complete adjuvant-injected birds were negative in the mycoplasma culture. The specificity and sensitivity of the qPCR for synovial fluid samples were 100% (95% CI = 65 to 100) and 93% (95% CI = 77 to 99); for joint swabs they were 100% (95% CI = 74 to 100) and 73% (95% CI = 61 to 83), respectively. Positive qPCR results (10(0.3) (to) (4.6) CFU eq./ml) were found until the end of the experiment (12 weeks post inoculation). At the end of the study, eight out of 16 joint swabs from birds without macroscopic joints lesions were positive in the qPCR (10(2.0) (to) (2.8) CFU eq./ml). Under the conditions of this study, the sensitivity of the qPCR was higher than that of direct mycoplasma culture (P< 0.0001) during the acute, subacute and chronic stages of arthritis.

Is the role of Chlamydia trachomatis underestimated in patients with suspected reactive arthritis?

Reactive arthritis is usually caused by bacteria of either the enteric or genital tracts. In the genital tract, Chlamydia trachomatis is perhaps the only aetiological agent. In Iran, newer evidence suggests that as C. trachomatis is more commonly found in the general population than was previously believed, its role in reactive arthritis may well be currently overlooked. In this review, as well as emphasizing the potential role of C. trachomatis in reactive arthritis in patients from developing countries, we also make recommendations for further clinical studies to determine its prevalence. Moreover, we also stress the need for standardization of new testing methodologies for C. trachomatis, including the use of new commercial systems in an attempt to determine a truer picture of chlamydial infection in reactive arthritis.

Detection of Chlamydia trachomatis-DNA in synovial fluid: evaluation of the sensitivity of different DNA extraction methods and amplification systems

INTRODUCTION

Polymerase chain reaction (PCR) and ligase chain reaction (LCR) are used in research for detection of Chlamydia trachomatis (C. tr.) in synovial fluid (SF). However there is no standardized system for diagnostic use in clinical practice, therefore this study aimed at determining the molecular biology method best suited to detect C. tr. from SF.

METHODS

SF samples were spiked with C. tr. elementary bodies (EB) and human peripheral blood monocytes (PBMo) persistently infected with C. tr. in vitro to evaluate the sensitivity of different molecular biology methods and assays. Five different DNA-extraction methods were tested: 1) Alkaline lysis, 2) QIAex II Gel Extraction Kit+ CTAB, 3) Chelex-extraction, 4) QIAmp Tissue Kit and 5) QIAmp DNA Stool Kit. All DNA extracts were subjected to 5 different DNA amplification systems to detect C. tr.- DNA in the spiked SF samples: two C. tr. -omp1-- directed PCR, one C. tr.-plasmid-PCR, one C. tr. -16s RNA directed PCR, and one commercially available LCR (LCX), Abbott laboratories).

RESULTS

In SF samples spiked with C. tr.-EB and with C. tr.-PBMo, alkaline lysis, detecting 1 C. tr.-EB/ml SF, 0,1 C. tr.-PBMo/ml SF and QIAmp gel extraction kit+ CTAB detecting 0,1 C. tr. -EB/ml SF, 1 C. tr.-PBMo/ml, respectively, allowed most sensitive detection of the organism in combination with the C. tr.- omp1-(152 bp) PCR. Sensitivity decreased in all methods after storage of the DNA of C. tr.- dilution series at -20 degrees C for 4 months by at least one log phase.

CONCLUSIONS

The sensitivity to detect C. tr.- DNA from SF is highly dependent on the DNA extraction method and the detection system applied. Alkaline lysis as well as the QIAmp Gel extraction kit + CTAB in combination with C. tr.- omp1 - (152 bp) PCR evolved as the most sensitive methods to identify C. tr. in serial dilutions.

Reactive and undifferentiated arthritis in North Africa: use of PCR for detection of Chlamydia trachomatis

Little is known about the possible role of Chlamydia in patients with reactive or unclassified arthritis in North Africa. This study used polymerase chain reaction (PCR) to survey this population. In addition, we compared the results in three different laboratories for PCR analyses for Chlamydia trachomatis (Ct) in synovial fluid (SF) and tissue (ST) from these North African patients with reactive arthritis (ReA), undifferentiated arthritis (UA), and in rheumatoid arthritis (RA) and osteoarthritis (OA). Eight ReA (six posturethritic, two postenteritic), 23 UA, 13 OA, and 12 RA patients were studied in Algeria, Morocco, and Tunisia. Serum, SF, and ST were obtained from each patient. Ct-PCR was performed in the three different laboratories and compared to Ct-serology [microimmunofluorescence (MIF) and anti-hsp60 enzyme-linked immunosorbent assay (ELISA)] performed in one laboratory. The rate of Ct-PCR positivity in SF/ST was low: none out of the eight ReA and three out of 23 UA patients. In the controls, Ct DNA was detected in two OA SF and in one RA SF. There was no concordance for Ct-PCR positivity between the three laboratories. MIF suggested previous Ct infection (IgG-positive) in two out of five posturethritic ReA, none out of one postenteritic ReA, one out of 17 UA, and nine out of 21 RA/OA patients tested. No MIF-positive patient was PCR-positive from SF or ST. However, anti-hsp60 IgG was detected in all four out of four patients positive by PCR and in 11 out of 44 PCR-negative patients (p = 0.002). In this multinational comparative study, the rate of Ct-PCR-positive synovial specimens in North African ReA/UA patients was low. Concordance among the three PCR testing laboratories was poor indicating the need for test standardization. All Ct-PCR-positive patients were found positive by anti-hsp60 IgG serology.

Development of a molecular methodology to quantify Staphylococcus epidermidis in surgical wash-out samples from prosthetic joint replacement surgery

Prosthetic joint infection is a serious complication of total joint arthroplasty that causes great morbidity in affected individuals. The most common cause of prosthesis associated infections are members of Staphylococcus spp., including Staphylococcus epidermidis. Culture has served as the gold standard for diagnosis, despite obvious shortcomings in terms of sensitivity and time. Bacterial genomic DNA extraction methodologies were evaluated for optimal recovery of genomic DNA from sterilised wash-out samples, spiked with S. epidermidis. Real time Polymerase chain reaction (PCR) assays targeting the S. epidermidis specific gseA gene were designed to reliably detect and quantify S. epidermidis. Sixty post-operative wash-out samples from primary hip and knee arthroplasties were taken aseptically. All were shown to be culture negative using the culture-dependent approach. These were samples were subjected to S. epidermidis-specific real time PCR. Standard curve showed good linearity. Sensitivity limit of the assay was <10 CFU S. epidermidis per sample. Reproducibility of the assay was confirmed. S. epidermidis was not identified in any of these samples using the novel species specific SYBR Green real time PCR technique. Results indicated that wash-out samples were true negatives and did not harbour S. epidermidis. To support this, patients displayed no symptoms of infection. To illustrate the full effectiveness of the novel real time PCR assay, a larger number of samples need to be tested (>1,000 patients).

Inhibitor-free DNA for real-time PCR analysis of synovial fluid from horses, cattle and pigs

The potential of five different commercial DNA isolation methods to remove real-time PCR inhibitors from the synovial fluid of horses, cattle and pigs was investigated. All kits with the exception of one included a silica column-based purification of the DNA. With the fifth kit, DNA purification is achieved by removing contaminating macromolecules by a desalting process. We used a recently developed method based on comparison of the real-time PCR signal of an artificial target incorporated into each PCR reaction in the presence of the isolated DNA from the sample, and in control samples containing water instead of isolated DNA. This was followed by statistical analysis of the data. Inhibition and subsequent reduction of the endpoint fluorescence in the real-time PCR reaction was encountered in many cases. Less frequently, the target copy number in the samples was underestimated. However, we found no experimental evidence of a negative influence of the reduced endpoint fluorescence signal on the detection limit of the real-time PCR assay. All kits tested were useful for analyzing pelleted synovial fluid from horses, cattle and pigs. When analyzing non-pelleted synovial fluid, three kits - two based on silica columns and one employing a desalting process - yielded inhibitor-free DNA for real-time PCR analysis.

Correlation between Yersinia enterocolitica and type I collagen reactivity in patients with arthropathies

We investigated the association with Yersinia infection in patients with arthropathies in our region. To assess the reactivity to articular antigens, the correlation of anti-Yersinia with anti-type I and type II collagen antibodies was studied. Sera from 124 patients with musculoskeletal symptoms, and 47 synovial fluids (SF) from patients with rheumatoid arthritis (RA), spondyloarthopathies (SpA) or osteoarthritis (OA) were examined. Immunoglobulins against Yersinia enterocolitica, type I and type II collagens were determined by enzyme-linked immunosorbent assay. Immunoglobulin (Ig) A to Yersinia lipopolysaccharide (LPS) was present in 13/124 sera (10%) and 3/47 SF (6%). By Western blot, IgA to Yersinia outer proteins (Yops) was found in 14/124 sera (11%) and 2/47 SF (4%). Yersinia DNA from SF was not amplified by polymerase chain reaction. We found a significant correlation with anti-collagen type I but not type II antibodies. These results suggest different reactivity to articular collagen in patients with Yersinia antibodies.

Identification of bacteria in endodontic infections by sequence analysis of 16S rDNA clone libraries

A significant proportion of oral bacteria are unable to undergo cultivation by existing techniques. In this regard, the microbiota from root canals still requires complementary characterization. The present study aimed at the identification of bacteria by sequence analysis of 16S rDNA clone libraries from seven endodontically infected teeth. Samples were collected from the root canals, subjected to the PCR with universal 16S rDNA primers, cloned and partially sequenced. Clones were clustered into groups of closely related sequences (phylotypes) and identification to the species level was performed by comparative analysis with the GenBank, EMBL and DDBJ databases, according to a 98 % minimum identity. All samples were positive for bacteria and the number of phylotypes detected per subject varied from two to 14. The majority of taxa (65·2 %) belonged to the phylum Firmicutes of the Gram-positive bacteria, followed by Proteobacteria (10·9 %), Spirochaetes (4·3 %), Bacteroidetes (6·5 %), Actinobacteria (2·2 %) and Deferribacteres (2·2 %). A total of 46 distinct taxonomic units was identified. Four clones with low similarity to sequences previously deposited in the databases were sequenced to nearly full extent and were classified taxonomically as novel representatives of the order Clostridiales, including a putative novel species of Mogibacterium. The identification of novel phylotypes associated with endodontic infections suggests that the endodontium may still harbour a relevant proportion of uncharacterized taxa.

Synovial fluid changes in induced infectious arthritis in calves

The objective was to develop an experimental model of septic arthritis in calves and to evaluate the effect of treatment on cytologic and bacteriologic variables of synovial fluid. The right tarsus of 7 healthy Holstein bull calves were inoculated with 10⁸ colony‐forming units of viable Escherichia coli of a pap‐positive strain (day 1). On day 2, joint lavage was performed and antibiotic treatment was instituted. Cytologic examinations, bacterial cultures, and pap factor determinations by polymerase chain reaction (PCR) were performed on synovial fluid samples that were collected daily until day 4, then every 4 days until day 24. Results of physical examination, the severity of lameness, and swelling were recorded. Clinical signs of septic arthritis appeared on day 2 and persisted until day 9 for all calves. Bacterial cultures from all calves were positive for E coli on day 2, and remained positive until day 3 for 1 calf and until day 4 for 5 calves. In addition, PCR results were positive for all calves, with 6 positive through day 3 and 1 positive through day 4, after which a positive result was again obtained on day 24. Synovial fluid neutrophil counts and white blood cell counts were significantly increased on days 2–4; however, synovial total protein concentrations were increased (P < .05) throughout the experiment in comparison to day 1. Results of all bacterial cultures were negative on day 8, although clinicopathologic signs of inflammation persisted until day 20. This model successfully induced acute septic arthritis in calves. Rapid recovery occurred within 1 week when an appropriate treatment was instituted early in the course of the disease

Synovial fluid changes in induced infectious arthritis in calves

The objective was to develop an experimental model of septic arthritis in calves and to evaluate the effect of treatment on cytologic and bacteriologic variables of synovial fluid. The right tarsus of 7 healthy Holstein bull calves were inoculated with 10(8) colony-forming units of viable Escherichia coli of a pap-positive strain (day 1). On day 2, joint lavage was performed and antibiotic treatment was instituted. Cytologic examinations, bacterial cultures, and pap factor determinations by polymerase chain reaction (PCR) were performed on synovial fluid samples that were collected daily until day 4, then every 4 days until day 24. Results of physical examination, the severity of lameness, and swelling were recorded. Clinical signs of septic arthritis appeared on day 2 and persisted until day 9 for all calves. Bacterial cultures from all calves were positive for E. coli on day 2, and remained positive until day 3 for 1 calf and until day 4 for 5 calves. In addition, PCR results were positive for all calves, with 6 positive through day 3 and 1 positive through day 4, after which a positive result was again obtained on day 24. Synovial fluid neutrophil counts and white blood cell counts were significantly increased on days 2-4; however, synovial total protein concentrations were increased (P < .05) throughout the experiment in comparison to day 1. Results of all bacterial cultures were negative on day 8, although clinicopathologic signs of inflammation persisted until day 20. This model successfully induced acute septic arthritis in calves. Rapid recovery occurred within 1 week when an appropriate treatment was instituted early in the course of the disease.

Chlamydia-induced arthritis

PURPOSE OF REVIEW

Chlamydia-induced arthritis is the most frequent form of reactive arthritis in Western countries. This article gives an overview of the recent findings with respect to diagnosis, pathogenesis, and therapy of the disease.

RECENT FINDINGS

Recent advances in the modification and standardization of polymerase chain reaction techniques give promise to identify Chlamydia more frequently from joint samples. Based on the sequenced chlamydial genome, considerable progress has been achieved in the understanding of the Chlamydia-host cell interaction, indicating that persistence is an alternate state of the bacteria used by Chlamydia to escape the immune system of the host rather than a general stress response. Furthermore, Chlamydia has the ability to reprogram the host cell by chlamydial effector proteins, which are transported from the inclusion into the host cell cytoplasm. The role of HLA-B27 is discussed in view of the pathogenesis of the disease. HLA-B27 should be considered a risk factor for chronic and/or axial disease rather than a true susceptibility factor for the development of Chlamydia-induced arthritis. No progress has been made in terms of causative therapy aiming at eradication of the bacteria. Tumor necrosis factor-alpha blocking agents may represent a new option in cases that are refractory to therapy.

SUMMARY

Molecular biology not only has improved the ability to detect Chlamydia in the joint for diagnostic purposes but also has extended the current understanding of the pathogenesis of the disease. In contrast to this progress, causative therapy of Chlamydia-induced arthritis is still an unfulfilled need.

Three month treatment of reactive arthritis with azithromycin: a EULAR double blind, placebo controlled study

OBJECTIVE

To determine the efficacy of weekly treatment with oral azithromycin for 13 weeks on the severity and resolution of reactive arthritis (ReA).

METHODS

186 patients from 12 countries were enrolled in a randomised, double blind, placebo controlled trial. Inclusion criteria were inflammatory arthritis of < or =6 swollen joints, and disease duration of < or =2 months. All patients received a single azithromycin dose (1 g) as conventional treatment for possible Chlamydia infection, and were then randomly allocated to receive weekly azithromycin or placebo. Clinical assessments were made at 4 week intervals for 24 weeks.

RESULTS

152 patients were analysable (34 failed entry criteria), with a mean (SD) age of 33.8 (9.4) and duration of symptoms 30.7 (17.5) days. Mean C reactive protein (CRP) was 48 mg/l, and approximately 50% of those typed were HLA-B27+, suggesting that the inclusion criteria successfully recruited patients with acute ReA. Treatment and placebo groups were well matched for baseline characteristics. There were no statistical differences for changes in any end point (swollen and tender joint count, joint pain, back pain, heel pain, physician and patient global assessments, and CRP) between the active treatment and placebo groups, analysed on an intention to treat basis or according to protocol completion. The time to resolution of arthritis and other symptoms or signs by life table analyses was also not significantly different. Adverse events were generally mild, but were more commonly reported in the azithromycin group.

CONCLUSIONS

This large trial has demonstrated that prolonged treatment with azithromycin is ineffective in ReA.

Cytokine profile in serum and synovial fluid of arthritis patients with Chlamydia trachomatis infection

Chlamydia trachomatis (Ct)-induced arthritis (CtIA) is characterized by persistent Ct infection, which stimulates secretion of cytokines in vitro. We therefore investigated whether CtIA patients have a unique cytokine profile in synovial fluid or serum in vivo. Because underlying Ct infection is overlooked in a high percentage of patients with initially diagnosed undifferentiated oligoarthritis (UOA), we examined whether determination of cytokines might also be of diagnostic relevance for this arthritis form. Matched serum and synovial fluid specimens from 26 patients with CtIA were analyzed and compared to those from 34 patients with UOA in whom Ct infection was excluded and those of nine patients with rheumatoid arthritis (RA). In 15 CtIA patients, Ct DNA from synovial fluid could be amplified by polymerase chain reaction. The following cytokine or cytokine antagonists were measured by enzyme-linked immunosorbent assay: interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, IL-6, IL-1 receptor antagonist, and soluble TNF receptor p75. No statistically significant differences in cytokine levels between patients with CtIA or the other arthritis forms were detected. Also, comparison between CtIA patients with (n = 17) and without Chlamydia DNA (n = 9) in synovial fluid revealed no significant differences for these cytokines. Cytokine levels in serum and synovial fluid were not different between CtIA, UOA without Ct infection, and RA patients. The intracellular presence of Ct was not associated with a specific profile of these cytokines in vivo.

Chlamydial conjunctivitis (in adults), uveitis, and reactive arthritis, including SARA. Sexually acquired reactive arthritis

This chapter deals with Chlamydia -induced ocular and rheumatic diseases of the adult. All of these may follow a primary urogenital infection with Chlamydia trachomatis in genetically predisposed patients. Besides the infection with Chlamydia trachomatis, infections with Chlamydia pneumoniae and Chlamydia psittaci are also discussed as possible causative agents. Chlamydial conjunctivitis is frequently a secondary infection, and the organism is transferred from the urogenital tract to the eye by autoinoculation. Uveitis and reactive arthritis are believed to be triggered - among other infections - by a preceding urogenital infection. Both of them are closely associated with HLA-B27 positivity. The simultaneous occurrence of uveitis and reactive arthritis is termed Reiter's syndrome. We report on clinical characteristics, diagnosis and the role of Chlamydia in the pathogenesis of chlamydial conjunctivitis, uveitis and reactive arthritis as well as on the currently recommended treatment regimens.

Reactive arthritis or chronic infectious arthritis?

Microbes reach the synovial cavity either directly during bacteraemia or by transport within lymphoid cells or monocytes. This may stimulate the immune system excessively, triggering arthritis. Some forms of ReA correspond to slow infectious arthritis due to the persistence of microbes and some to an infection triggered arthritis linked to an extra-articular site of infection.

Chlamydia and Borrelia DNA in synovial fluid of patients with early undifferentiated oligoarthritis: results of a prospective study

OBJECTIVE

More than 50% of patients with synovitis involving 1-4 joints remain classified as having undifferentiated oligoarthritis (UOA) after 1 year of disease. The clinical presentation is often similar to that of reactive arthritis (ReA) and other spondylarthropathies or to Lyme arthritis. We therefore determined how often Chlamydia trachomatis (Ct) and Borrelia burgdorferi (Bb) can be identified in patients with UOA, by using an extensive laboratory approach.

METHODS

We prospectively studied 52 patients with UOA who presented at an early synovitis clinic in a region highly endemic for Lyme disease. Patients were examined by standardized clinical and immunoserologic procedures. Synovial fluid was screened for the presence of Ct and Bb DNA by polymerase chain reaction (PCR). Urine was tested for Ct DNA by ligase chain reaction, and serum was tested for Ct antibodies by enzyme-linked immunosorbent assay and Bb antibodies by hemagglutination test and Western blotting. PCR results in the UOA patients were compared with the results in cohorts of patients with definite rheumatoid arthritis (RA), Lyme arthritis, and Chlamydia-induced arthritis (CIA).

RESULTS

In the synovial fluid of 9 of 52 patients with UOA (17%), we found Ct DNA, and in 6 of the 52 patients (12%), Bb DNA was found. The frequency of bacteria-specific DNA was 50% (7 of 14) in CIA patients and 69% (11 of 16) in patients with Lyme arthritis. No Bb or Ct DNA was found in the synovial fluid of the 31 RA patients.

CONCLUSION

With optimized PCR protocols, it is possible to detect considerable levels of Bb and Ct DNA in the synovial fluid of patients with UOA. Although the presence of bacterial DNA does not unequivocally prove its etiologic significance, we suggest that at least one-third of patients with UOA may have a form of ReA that involves asymptomatic primary infection.

Frequency of triggering bacteria in patients with reactive arthritis and undifferentiated oligoarthritis and the relative importance of the tests used for diagnosis

OBJECTIVE

Reactive arthritis (ReA) triggered by Chlamydia trachomatis or enteric bacteria such as yersinia, salmonella, Campylobacter jejuni, or shigella is an important differential diagnosis in patients presenting with the clinical picture of an undifferentiated oligoarthritis (UOA). This study was undertaken to evaluate the best diagnostic approach.

PATIENTS AND METHODS

52 patients with ReA, defined by arthritis and a symptomatic preceding infection of the gut or the urogenital tract, and 74 patients with possible ReA, defined by oligoarthritis without a preceding symptomatic infection and after exclusion of other diagnoses (UOA), were studied. The following diagnostic tests were applied for the identification of the triggering bacterium: for yersinia induced ReA-stool culture, enzyme immunoassay (EIA), and Widal's agglutination test for detection of antibodies to yersinia; for salmonella or campylobacter induced ReA-stool culture, EIA for the detection of antibodies to salmonella and Campylobacter jejuni; for infections with shigella-stool culture; for infections with Chlamydia trachomatis-culture of the urogenital tract, microimmunofluorescence and immunoperoxidase assay for the detection of antibodies to Chlamydia trachomatis.

RESULTS

A causative pathogen was identified in 29/52 (56%) of all patients with ReA. In 17 (52%) of the patients with enteric ReA one of the enteric bacteria was identified: salmonella in 11/33 (33%) and yersinia in 6/33 (18%). Chlamydia trachomatis was the causative pathogen in 12/19 (63%) of the patients with urogenic ReA. In patients with the clinical picture of UOA a specific triggering bacterium was also identified in 35/74 (47%) patients: yersinia in 14/74 (19%), salmonella in 9/74 (12%), and Chlamydia trachomatis in 12/74 (16%).

CONCLUSIONS

Chlamydia trachomatis, yersinia, and salmonella can be identified as the causative pathogen in about 50% of patients with probable or possible ReA if the appropriate tests are used.

Optimised sample DNA preparation for detection of Chlamydia trachomatis in synovial tissue by polymerase chain reaction and ligase chain reaction

OBJECTIVE

Molecular biology techniques such as polymerase chain reaction (PCR) and ligase chain reaction (LCR) are routinely used in research for detection of C trachomatis DNA in synovial samples, and these methods are now in use in some clinical laboratories. This study aimed at determining the method best suited to molecular diagnosis of C trachomatis by examining four standard DNA preparation methods using chlamydia spiked synovial tissue and chlamydia infected monocytes.

METHODS

Synovial tissue from a chlamydia negative patient with rheumatoid arthritis was spiked with defined numbers of C trachomatis elementary bodies (EB). Purified human peripheral monocytes from normal donors were infected with the organism at a multiplicity of infection 1:1 in vitro and harvested after four days. DNA was prepared from all samples by four methods: (1) QIAmp tissue kit; (2) homogenisation in 65 degrees C phenol; (3) incubation at 97 degrees C; (4) proteinase K digestion at 97 degrees C. DNA from methods 1 and 2 was subjected to PCR using two different primer sets, each targeting the C trachomatis omp1 gene. LCR was done on DNA prepared by each method.

RESULTS

In synovial tissue samples spiked with EB, and in monocytes persistently infected with the organism, preparation of template using the QIAmp tissue kit (method 1) and the hot phenol extraction technique (method 2) allowed sensitive detection of C trachomatis DNA. These methods also produced template from both sample types for LCR. DNA prepared by heat denaturation (method 3) allowed only low sensitivity chlamydia detection in LCR and did not work at all for PCR. Proteinase K digestion plus heat denaturation (method 4) gave template that did not allow amplification in either PCR or LCR assays.

CONCLUSIONS

The sensitivity of detection for C trachomatis DNA in synovial tissue by PCR and LCR depends strongly on the method used for preparation of the amplification template. LCR targeting the multicopy chlamydial plasmid and two nested PCR assay systems targeting the single copy omp1 gene showed roughly equivalent sensitivity. Importantly, template preparation method and the specific PCR primer system used for screening must be optimised in relation to one another for highest sensitivity.