The polymerase chain reaction in infectious and post-infectious arthritis. A review

Recommendations on diagnosis and antimicrobial treatment of infections after anterior cruciate ligament reconstruction (ACL-R) endorsed by ESSKA and EBJIS

Infection after anterior-cruciate ligament reconstruction (ACL-R) is a rare but devastating complication affecting predominantly young and sportive individuals. A timely and correct diagnosis as well as an optimized management are paramount to circumvent serious sequelae and compromise in life quality. These recommendations are primarily intended for use by infectious disease specialists and microbiologists, but also orthopedic surgeons and other healthcare professionals who care for patients with infections after ACL-R. They are based on evidence mainly originating from observational studies and opinions of experts in the field and cover the management of infections after ACL-R with a special focus on etiology, diagnosis, antimicrobial treatment and prevention. Comprehensive recommendations on prevention, surgical treatment and rehabilitation are presented separately in a document primarily addressing orthopedics professionals.

Detection of bacterial DNA in synovial fluid in dogs with arthritis: a comparison between bacterial culture and 16S rRNA polymerase chain reaction

Background

Septic arthritis (SA) is a serious condition in dogs that requires a prompt diagnosis and treatment to minimize long-term joint pathology. Although bacterial detection in synovial fluid (SF) through culture or cytology is often performed to confirm diagnosis, the sensitivity of these tests is low. The need for a reliable diagnostic tool to confirm the presence of bacteria in SF in humans has led to the increased use of 16S rRNA (i.e., ribosomal RNA) gene sequencing by polymerase chain reaction (16S rRNA PCR). The aim of this prospective clinical study was to compare the sensitivity and specificity of 16S rRNA PCR with bacterial culture on blood agar plates after pre-incubation of SF in paediatric blood bacterial culture bottles to identify bacteria in dogs with clinical signs of SA and to investigate the usefulness of these methods as diagnostic tools.

Results

Ten dogs with clinical signs of SA, nine with osteoarthritis (OA, control group) and nine with clinical signs of immune-mediated polyarthritis (IMPA, second control group) were examined. Bacterial culture was positive in seven of 10 dogs with clinical SA, of which only two were positive by 16S rRNA PCR. The sensitivity of 16S rRNA PCR and bacterial culture analysis for dogs with clinical SA were 20% and 70%, respectively. All SF samples collected from control group (n = 9) and second control group (n = 14) animals were negative on culture, and 16S rRNA PCR rendered a specificity of 100%.

Conclusions

Our study showed a lower sensitivity of 16S rRNA PCR than bacterial culture for dogs with clinical SA. Our findings suggest that there is currently no advantage in using 16S rRNA PCR as a diagnostic tool for dogs with clinical SA. Furthermore, our study indicates that pre-incubation in paediatric blood bacterial culture bottles before bacterial cultivation on blood agar plates might enhance bacterial culture sensitivity compared to other culture methods.

Clinical and laboratory profile in confirmed vs. suspected septic arthritis patients and its relevance in decision making: A comparative cross-sectional study

PURPOSE

There were 10%-30% of patients with adult-onset septic arthritis (SA) exhibiting sterile synovial fluid (SF), and the uncertainty in the determining diagnosis of these patients posed a challenge in management. The purpose of this study was to investigate the differences between confirmed (Newman A) and suspected (Newman B & C) SA in adults.

METHODS

This was a descriptive study with a cross-sectional study design conducted at a tertiary referral centre from July 2016 to February 2019. Patients aged over 18 years presented to the emergency department with clinical features suggestive of SA and were scheduled to undergo arthrotomy and joint lavage by the treating surgeon were included in the study. Patients with prosthetic joint infections and open joint injuries were excluded. Patients' demographic data, clinical features and laboratory parameters were collected. The clinical and laboratory profile (blood and SF) of the adult patients presenting with features suggestive of SA based on Newman criteria was statistically analyzed by SPSS version 20 software and Microsoft Excel. The categorical variables were expressed as proportions while the continuous variables were expressed as mean (SD) or median (IQR) depending upon the normality of distribution. The difference between the two groups for categorical variables was assessed using the Chi-square test and the difference for continuous variables was assessed using the unpaired t-test and the Mann-Whitney test depending upon normality. A p value < 0.05 was considered significant.

RESULTS

Thirty-six patients were divided into confirmed (n = 19) or suspected (n = 17) SA for assessment based on SF culture. The median (IQR) age of the patients was 50 years (37-60 years). There was no significant difference in demographic, clinical and laboratory parameters between the concerned groups. Eight patients presented with fever. Among the confirmed SA cases, 8 were negative for C-reactive protein and 6 had synovial white blood cell count <50,000. Staphylococcus species were isolated in 8 cases. The most common risk factors for SA were chronic kidney disease (25.0%), diabetes mellitus (25.0%), pharmacologic immunosuppression (16.7%), recent joint surgery (11.1%) and distant site infection (11.1%).

CONCLUSION

SA is an orthopaedic emergency that needs prompt and aggressive treatment to prevent catastrophic complications. Confirmed and suspected cases of SA exhibit similar demography, clinical features and laboratory parameters at presentation which may mislead the treating surgeon. Management should be based on sound clinical judgment in the event of failure to culture microorganisms.

[A case of gonococcal arthritis: Diagnostic difficulties and usefulness of synovial fluid PCR]

INTRODUCTION

The incidence of Neisseria gonorrhoeae septic arthritis remains low in the general population. Its clinical and microbiological diagnostic remains difficult.

CASE REPORT

We report a 44-year-old man who presented with a monoarthritis of the right ankle. The diagnosis of gonoccocal septic arthritis was obtained by PCR from the joint fluid. Treatment with ceftriaxone was effective.

CONCLUSION

In patients with high risk of N. gonorrhoeae infection, PCR for detection of gonorrhea in synovial fluid could potentially facilitate the diagnostic of gonococcal septic arthritis.

A guide to utilization of the microbiology laboratory for diagnosis of infectious diseases: 2013 recommendations by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM)(a)

The critical role of the microbiology laboratory in infectious disease diagnosis calls for a close, positive working relationship between the physician and the microbiologists who provide enormous value to the health care team. This document, developed by both laboratory and clinical experts, provides information on which tests are valuable and in which contexts, and on tests that add little or no value for diagnostic decisions. Sections are divided into anatomic systems, including Bloodstream Infections and Infections of the Cardiovascular System, Central Nervous System Infections, Ocular Infections, Soft Tissue Infections of the Head and Neck, Upper Respiratory Infections, Lower Respiratory Tract infections, Infections of the Gastrointestinal Tract, Intraabdominal Infections, Bone and Joint Infections, Urinary Tract Infections, Genital Infections, and Skin and Soft Tissue Infections; or into etiologic agent groups, including Tickborne Infections, Viral Syndromes, and Blood and Tissue Parasite Infections. Each section contains introductory concepts, a summary of key points, and detailed tables that list suspected agents; the most reliable tests to order; the samples (and volumes) to collect in order of preference; specimen transport devices, procedures, times, and temperatures; and detailed notes on specific issues regarding the test methods, such as when tests are likely to require a specialized laboratory or have prolonged turnaround times. There is redundancy among the tables and sections, as many agents and assay choices overlap. The document is intended to serve as a reference to guide physicians in choosing tests that will aid them to diagnose infectious diseases in their patients.

Broad-range PCR, cloning and sequencing of the full 16S rRNA gene for detection of bacterial DNA in synovial fluid samples of Tunisian patients with reactive and undifferentiated arthritis

Introduction

Broad-range rDNA PCR provides an alternative, cultivation-independent approach for identifying bacterial DNA in reactive and other form of arthritis. The aim of this study was to use broad-range rDNA PCR targeting the 16S rRNA gene in patients with reactive and other forms of arthritis and to screen for the presence of DNA from any given bacterial species in synovial fluid (SF) samples.

Methods

We examined the SF samples from a total of 27 patients consisting of patients with reactive arthritis (ReA) (n = 5), undifferentiated arthritis (UA) (n = 9), rheumatoid arthritis (n = 7), and osteoarthritis (n = 6) of which the latter two were used as controls. Using broad-range bacterial PCR amplifying a 1400 bp fragment from the 16S rRNA gene, we identified and sequenced at least 24 clones from each SF sample. To identify the corresponding bacteria, DNA sequences were compared to the EMBL (European Molecular Biology Laboratory) database.

Results

Bacterial DNA was identified in 20 of the 27 SF samples (74, 10%). Analysis of a large number of sequences revealed the presence of DNA from more than one single bacterial species in the SF of all patients studied. The nearly complete sequences of the 1400 bp were obtained for most of the detected species. DNA of bacterial species including Shigella species, Escherichia species, and other coli-form bacteria as well as opportunistic pathogens such as Stenotrophomonas maltophilia and Achromobacter xylosoxidans were shared in all arthritis patients. Among pathogens described to trigger ReA, DNA from Shigella sonnei was found in ReA and UA patients. We also detected DNA from rarely occurring human pathogens such as Aranicola species and Pantoea ananatis. We also found DNA from bacteria so far not described in human infections such as Bacillus niacini, Paenibacillus humicus, Diaphorobacter species and uncultured bacterium genera incertae sedis OP10.

Conclusions

Broad-range PCR followed by cloning and sequencing the entire 16S rDNA, allowed the identification of the bacterial DNA environment in the SF samples of arthritic patients. We found a wide spectrum of bacteria including those known to be involved in ReA and others not previously associated with arthritis.

Broad range 16S rRNA gene PCR compared to bacterial culture to confirm presumed synovial infection in horses

The objectives of the present study were to evaluate the accuracy of broad range 16S rRNA gene PCR compared to bacterial culture for the detection of synovial infection in horses. The study included 57 synovial fluid samples from horses with presumed synovial infection and a control group consisting of 31 synovial fluid samples originating from clinically normal horses and horses with aseptic synovial inflammation. All samples were analysed by 16S PCR with reverse line blot (RLB) hybridisation. Synovial fluid samples were cultured using conventional agar plate methods (APM) and/or blood culture medium (BCM). The results of the study showed a superior detection rate (89.5%) for 16S PCR with RLB. Bacterial culture had lower sensitivity, but highly acceptable detection rates (77.6%) were observed using BCM. APM had very low sensitivity (37.8%) and infection was never detected by plate isolation without positive incubation in BCM. The highest sensitivity (91.8%) for the detection of synovial infection was achieved when the results of incubation in BCM and 16S PCR were combined. For all the tests, the specificity was higher than 90%.

Clinical Applications of the Polymerase Chain Reaction: An Update

The development, in the past decade, of nucleic acid amplification and detection methods is useful in the study of the etiopathogenesis, diagnosis, and management of a variety of clinical (including rheumatologic) disorders. An association between infectious agents and rheumatic disorders has been established through such methods as polymerase chain reaction. This article describes the principles behind polymerase chain reaction-based diagnosis and updates its clinical applications. It is beyond the scope of this article, however, to describe other nucleic acid amplification methods or to include a complete list of all polymerase chain reaction assays that have been developed. Other recent reviews offer additional details.

Advances in the Management of Septic Arthritis

Septic arthritis still continues to be a common and serious problem at major urban medical centers and is one of the most rapidly destructive forms of acute arthritis. The yearly incidence of bacterial arthritis varies from 2 to 10 per 100,000 in the general population to 30 to 70 per 100,000 in patients with rheumatoid arthritis and in patients with joint prostheses. Irreversible loss of joint function may develop in up to 50% of the patients. Despite better antimicrobial agents and improved hospital care, the fatality rate for this medical problem has not changed substantially during the past 30 years. An understanding of the risk factors and the pathogenesis of nongonoccocal bacterial arthritis and other forms of infectious arthritis, primarily in the context of a differential diagnosis and treatment, are important to avoid the delay in making a correct diagnosis and to improve the prognosis.

Detection of bacterial DNA in synovial fluid from horses with infectious synovitis

Standard culturing techniques are often unrewarding in confirming diagnosis of synovial infection in the equine patient. Several human studies report the use of sensitive polymerase chain reaction (PCR) techniques for the detection of bacterial involvement in acute synovitis. However, successful extraction of bacterial DNA directly from clinical samples from horses without prior culture has not been reported yet. The goal of this study was to develop a sensitive and reliable method for molecular detection and identification of bacterial species in synovial fluid from horses with infectious synovitis. Synovial fluid samples from 6 horses with culture confirmed synovial infection were used for broad range 16S rRNA gene PCR. Synovial aspirates of 2 healthy horses were used as negative controls. Following extraction and purification of synovial fluid DNA, all samples were processed by touchdown PCR. Amplicons were detected by reverse line blot hybridisation and visualised with chemiluminescence. Pathogen-specific detection of 16S rRNA gene sequences was successful in all 6 synovial fluid samples. No bacterial DNA was detected in the aspirates from the negative control horses using touchdown PCR followed by 25 additional cycles of amplification. The identity of the pathogens was confirmed by DNA sequencing of the amplicons. It can be concluded that broad range 16S rRNA gene PCR followed by reverse line blot hybridisation is a promising technique for detection of bacterial DNA in synovial fluid samples. Further research should aim at the detection of bacterial DNA in synovial fluid samples suspected of infection but having negative culture results. When the 16S PCR proves to be reliable and more sensitive than standard culturing techniques, it may become a powerful tool in the diagnosis of synovial infection.

Prospective comparative study of patients with culture proven and high suspicion of adult onset septic arthritis

OBJECTIVE

To investigate whether patients with acute septic arthritis (SA) diagnosed by positive synovial fluid (SF) culture (Newman grade A) have different clinical and serological features from those with sterile SF in whom there is nonetheless a high suspicion of SA (Newman grades B and C).

PATIENTS AND METHODS

A prospective 12 month multicentre hospital based study of adult patients with SA recruited 47 patients with culture positive SA and 35 patients with clinically suspected SA but sterile SF.

RESULTS

Patient demography, clinical and laboratory features at presentation were similar irrespective of the underlying diagnosis, SF culture, and the presence of prosthetic joints. Medical and surgical treatment and outcome were comparable in the two patient groups. Patients with both suspected and proven SA were more likely to be from the more socially deprived areas of our community (p<0.0001).

CONCLUSION

Patients in whom there is a high clinical suspicion of SA are comparable to those patients with SA with a positive SF culture and have similar morbidity and mortality on follow up. Therefore, if clinical suspicion of SA is high then it is correct to treat as SA in the absence of bacterial proof.

Applications of polymerase chain reaction in rheumatology

Polymerase chain reaction (PCR) is a highly sensitive and specific method for detection and quantification of specific nucleic acids from a clinical sample. With its use, genetic, infectious, neoplastic, and autoimmune diseases can be diagnosed and managed with a high level of sensitivity, accuracy, and rapidity. This technique exactly reproduces unlimited copies of DNA, even if only a small amount are present initially. PCR assays can detect presence of fastidious and slow-growing microorganisms, such as chlamydia, mycoplasmas, mycobacterias, and viruses directly from clinical specimens and also can detect antimicrobial resistance. The value of viral load measurement by nucleic acid amplification in the management of patients with HIV infection or hepatitis C has also been well established. From the point of view of a clinician, the applications of PCR are focused mainly in the amplification and detection of diagnostic DNA segments from the genomes of both pathogens and patients.

Advances in the management of septic arthritis

Bacterial arthritis still is a common and serious problem at mayor urban medical centers and is one of the most rapidly destructive forms of acute arthritis. The yearly incidence of bacterial arthritis varies from 2 to 10 per 100,000 in the general population to 30 to 70 per 100,000 in patients with rheumatoid arthritis and in patients with joint prostheses. Irreversible loss of joint function may develop in up to 50% of the patients. Despite better antimicrobial agents and improved hospital care, the fatality rate for this medical problem has not changed substantially during the past 25 years. An understanding of the risk factors and the pathogenesis of nongonoccocal bacterial arthritis and other forms of infectious arthritis, primarily in the context of a differential diagnosis and treatment, are important in order to avoid the delay in making a correct diagnosis and to improve the prognosis.

Rheumatic manifestations of HIV-AIDS

Infection by human immunodeficiency virus is characterized by a myriad of clinical manifestations affecting almost every organ system in the body. If untreated, it follows an inexorable course, leading to a profound state of immunosuppression and eventually death from opportunistic infection and/or development of lymphoproliferative malignancy and Kaposi's sarcoma. Rheumatic manifestations may develop at any time of the clinical spectrum, but usually are more often seen in late stages. A variety of disorders may be seen, particularly Reiter's syndrome and undifferentiated spondyloarthropathy. Most patients do well with conventional anti-inflammatory therapy, but some will require the use of immunosuppressive-cytotoxic therapy.

Hypertrophic osteoarthropathy can indicate recurrence of Whipple's disease

We report the case of a patient with Whipple's disease (WD) who developed hypertrophic osteoarthropathy (HOA) characterized by digital clubbing, periostosis of the tubular bones, and polysynovitis. The HOA disclosed the recurrence of the patient's WD, since polymerase chain reaction (PCR) analysis clearly demonstrated the presence of Tropheryma whippelii in the synovial fluid from the patient's left knee. Initiation of appropriate antibiotic therapy resulted in complete healing of all clinical rheumatologic manifestations within 2 months and in disappearance of radiographic bone changes at 7-month followup. We suggest that HOA be included within the spectrum of rheumatologic manifestations of WD, and that an evaluation for WD should be considered in patients, especially middle-aged men, presenting with HOA even without gastrointestinal symptoms. PCR analysis may be useful in accurate diagnosis and management of early WD with unusual clinical manifestations, and may contribute to decreased morbidity and mortality.

The evolving role of direct amplification tests in diagnosing osteoarticular infections caused by mycobacteria and fungi

Polymerase chain reaction-based direct amplification tests have been developed for many species of mycobacteria and fungi. Their applications in clinical medicine are evolving rapidly but are still not fully defined. Uncritical use of direct amplification tests for individual patients without a clear understanding of their limitations and how to integrate their results with other clinical and laboratory data may lead to incorrect patient management. Although presently available tests seem to be clinically useful when properly applied, further technical development and clinical studies are needed before these powerful diagnostic tools achieve their full value.