Bacterial arthritis

Serum Procalcitonin as a Useful Serologic Marker for Differential Diagnosis between Acute Gouty Attack and Bacterial Infection

PURPOSE

Patients with gout are similar to those with bacterial infection in terms of the nature of inflammation. Herein we compared the differences in procalcitonin (PCT) levels between these two inflammatory conditions and evaluated the ability of serum PCT to function as a clinical marker for differential diagnosis between acute gouty attack and bacterial infection.

MATERIALS AND METHODS

Serum samples were obtained from 67 patients with acute gouty arthritis and 90 age-matched patients with bacterial infection. Serum PCT levels were measured with an enzyme-linked fluorescent assay.

RESULTS

Serum PCT levels in patients with acute gouty arthritis were significantly lower than those in patients with bacterial infection (0.096±0.105 ng/mL vs. 4.94±13.763 ng/mL, p=0.001). However, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels showed no significant differences between the two groups. To assess the ability of PCT to discriminate between acute gouty arthritis and bacterial infection, the areas under the curves (AUCs) of serum PCT, uric acid, and CRP were 0.857 [95% confidence interval (CI), 0.798-0.917, p<0.001], 0.808 (95% CI, 0.738-0.878, p<0.001), and 0.638 (95% CI, 0.544-0.731, p=0.005), respectively. There were no significant differences in ESR and white blood cell counts between these two conditions. With a cut-off value of 0.095 ng/mL, the sums of sensitivity and specificity of PCT were the highest (81.0% and 80.6%, respectively).

CONCLUSION

Serum PCT levels were significantly lower in patients with acute gouty attack than in patients with bacterial infection. Thus, serum PCT can be used as a useful serologic marker to differentiate between acute gouty arthritis and bacterial infections.

Neutralization of MMP-2 protects Staphylococcus aureus infection induced septic arthritis in mice and regulates the levels of cytokines

Matrix metalloproteinases (MMPs) are crucial players in Staphylococcus aureus mediated synovial tissue destruction in the pathogenesis of septic arthritis. Bacterial insult increases proteolytic matrix fragments by activated chondrocytes and synovial fibroblasts leading to induction of matrix metalloproteinases. Tissue destruction via MMPs induced by bacterial products, necrotic tissues and proinflammatory cytokines have been reported. Cytokines like TNF-α, IL-1β released from host cells in response to S. aureus infection promote cartilage degradation by stimulating the production of MMPs. Antibiotic treatment can eradicate invading bacteria but elevated levels of cytokines and cytokines induced MMPs activation lead to progressive and devastating bone and cartilage destruction even after bacterial clearance. Like other MMPs, MMP-2 also contributes to extracellular matrix degradation in different types of arthritis. Release of certain pro inflammatory cytokines can also be regulated by MMP-2 activation leading to further tissue destruction. The role of MMP-2 in the pathogenesis of S. aureus infection induced septic arthritis and its influence on cytokines regulation needs further investigation. Whether neutralization of MMP-2 provides protection against Staphylococcus aureus infection induced septic arthritis in mice is an obvious question. Here we reported that neutralization of MMP-2 during S. aureus infection induced septic arthritis might be beneficial for preventing infection induced extracellular matrix destruction thereby decreasing bacterial burden in synovial tissues and regulating inflammatory cytokines in arthritic mice.

Adult Native Septic Arthritis in an Inner City Hospital: Effects on Length of Stay

The objective of this retrospective study was to assess what factors affected length of stay (LOS) in 183 adult patients with native septic arthritis. Diagnosis was based on a representative physical examination, fluid cell count/Gram stain, and organisms isolated from joint fluid culture. Data included demographics, comorbidities, laboratory results, treatment, and discharge times. Joint fluid cultures were positive in 55% (100 of 183) of the patients, and these patients were the subjects of this study. Blood cultures were taken for 65 patients and were positive in 54%; when positive, they were found to be the same as isolates from joint fluid analysis 91% of the time. Pathogens found in joint fluid analysis were as follows: methicillin-susceptible Staphylococcus aureus (MSSA), 44%; methicillin-resistant S aureus (MRSA), 21%; Streptococcus species, 14%; Pseudomonas, 10%; and other organisms, 11%. Surgical washout less than 24 hours from diagnosis affected LOS (12.25 vs 16.96 days for >24 hours; P<.05), but pathogen type and comorbid conditions did not. Average time for culture sensitivities was 4±1 days. Almost half of the patients had MSSA. Delays that could be controlled were getting an early diagnosis and expedient surgical washout of the joint. A lack of insurance and a requirement of intravenous antibiotics prolonged stay, whereas age, sex, and ethnicity did not. Waiting for bacterial sensitivities was a factor that could not be controlled. The authors believe that polymerase chain reaction or other technologies could lead to early diagnosis and expedient surgery. Effective oral antibiotics against resistant organisms would help the patients leave the hospital earlier. [Orthopedics. 2016; 39(4):e674-e679.].

Rapid exclusion of bacterial arthritis using a glucometer

Bacterial arthritis is a medical emergency. However, prompt diagnosis and differentiation from non-infectious diseases are challenging. As bacterial metabolism leads to glucose reduction, measurement of synovial fluid glucose seems to be a promising diagnostic approach. The purpose of this study was to determine whether synovial fluid glucose levels could be accurately measured by using a glucometer and to evaluate its diagnostic accuracy in diagnosing bacterial arthritis compared to currently available markers. In a prospective diagnostic study, 102 consecutive patients with atraumatic joint effusion were included. Synovial fluid glucose concentrations were determined using both glucometer and automated analyzer respectively. Synovial fluid culture, crystal analysis, and synovial cell analysis were performed. Blood samples were taken for blood cultures, analyses of serum infection markers, and serum glucose. There was a high correlation between synovial fluid glucose measured by the glucometer and the automated analyzer (r ² = 0.92). According to the receiver operating characteristic curve, a threshold of 1.4 mmol/l had a sensitivity of 100 % (95 % CI 78.2-100 %), a specificity of 92.0 % (95 % CI 84.1-96.7 %), a positive predictive value of 68.2 % (95 % CI 45.1-86.1 %), and a negative predictive value of 100 % (95 % CI 95.5-100 %). These results suggest that synovial fluid glucose concentrations could be reliably measured using a glucometer. Due to its simplicity, this test has the potential to be an adjunct in the diagnostic cascade of bacterial arthritis.

Staphylococcus aureus-Associated Musculoskeletal Infections

Musculoskeletal infections caused by Staphylococcus aureus are among the most difficult-to-treat infections. S. aureus osteomyelitis is associated with a tremendous disease burden through potential for long-term relapses and functional deficits. Although considerable advances have been achieved in diagnosis and treatment of osteomyelitis, the management remains challenging and impact on quality of life is still enormous. S. aureus acute arthritis is relatively seldom in general population, but the incidence is considerably higher in patients with predisposing conditions, particularly those with rheumatoid arthritis. Rapidly destructive course with high mortality and disability rates makes urgent diagnosis and treatment of acute arthritis essential. S. aureus pyomyositis is a common disease in tropical countries, but it is very seldom in temperate regions. Nevertheless, the cases have been increasingly reported also in non-tropical countries, and the physicians should be able to timely recognize this uncommon condition and initiate appropriate treatment. The optimal management of S. aureus-associated musculoskeletal infections requires a strong interdisciplinary collaboration between all involved specialists.

Evaluation of neutrophil-to-lymphocyte ratio as a marker of inflammatory response in septic arthritis

Is neutrophil-to-lymphocyte ratio high in patients with septic arthritis? Septic arthritis may lead to higher rates of morbidity or even mortality if not diagnosed on time. This study was planned to answer the question that “Could neutrophil-to-lymphocyte ratio be utilized to help to diagnose septic arthritis?” The cohort of the study consisted of 39 patients diagnosed with septic arthritis. After ruling out the patients who did not meet the research’s inclusion criteria, the data of 26 patients were evaluated. The control group was collected from healthy volunteers who were admitted to the internal medicine outpatient clinic for a routine medical checkup at the same period (n = 26). Complete blood count (CBC) parameters, C-reactive protein, erythrocyte sedimentation rate, and neutrophil-to-lymphocyte ratios of the septic arthritis and control groups were compared statistically. In comparison, neutrophil-to-lymphocyte ratios of the septic arthritis group were significantly higher than the control group. In conclusion, neutrophil-to-lymphocyte ratio can be utilized in the emergency department or in outpatient clinics to support the diagnosis of septic arthritis.

Temporomandibular Joint Septic Arthritis and Mandibular Osteomyelitis Arising From an Odontogenic Infection: A Case Report and Review of the Literature

Septic arthritis of the temporomandibular joint (TMJ) has been infrequently reported in the literature. Some investigators believe that this condition is under-reported because it is underdiagnosed. Misdiagnosis or late diagnosis of this condition can lead to serious morbidity, including fistula formation, intracranial abscess, fibrous or bony ankylosis, temporal bone or condylar osteomyelitis, growth alteration, and several others. This report describes a case of septic TMJ arthritis arising from direct spread of an odontogenic infection with subsequent development of mandibular osteomyelitis. The purpose of this case report is to 1) increase awareness of an underdiagnosed condition, 2) establish the seriousness of this infection, 3) for the first time report on a case of TMJ septic arthritis caused by Bacteroides infection, and 4) provide a review of the relevant literature.

Infections and arthritis

Bacteria, viruses, fungi, and parasites can all cause arthritis of either acute or chronic nature, which can be divided into infective/septic, reactive, or inflammatory. Considerable advances have occurred in diagnostic techniques in the recent decades resulting in better treatment outcomes in patients with infective arthritis. Detection of emerging arthritogenic viruses has changed the epidemiology of infection-related arthritis. The role of viruses in the pathogenesis of chronic inflammatory arthritides such as rheumatoid arthritis is increasingly being recognized. We discuss the various causative agents of infective arthritis and emphasize on the approach to each type of arthritis, highlighting the diagnostic tests, along with their statistical accuracy. Various investigations including newer methods such as nucleic acid amplification using polymerase chain reaction are discussed along with the pitfalls in interpreting the tests.

High Prevalence of Methicillin-Resistant Staphylococcus aureus among Patients with Septic Arthritis Caused by Staphylococcus aureus

BACKGROUND

This study investigated the clinical characteristics of patients with septic arthritis caused by Staphylococcus aureus and tried to identify the risk factors for methicillin-resistant S. aureus (MRSA) arthritis.

METHODS

Between January 2008 and December 2011, patients with septic arthritis caused by S. aureus were identified from the computerized databases of a regional hospital and a medical center in southern Taiwan. The medical records of these patients were retrospectively reviewed.

RESULTS

A total of 93 patients with S. aureus arthritis were identified, and MRSA arthritis was found in 38 (40.9%) cases. The mean age of the patients was 58 years, and 86 (92.5%) episodes were classified as community-acquired infections. Diabetes mellitus (n = 41, 44.1%) was the most common underlying disease, followed by chronic kidney disease and liver cirrhosis. Patients with MRSA arthritis were more frequently elderly and found in the setting of healthcare-associated infection than patients with methicillin-susceptible S. aureus (MSSA) infections. No other significant differences in clinical manifestations and outcomes were noted between these two groups of patients. Overall, the in-hospital mortality rate was 5.4%, and diabetes mellitus was the only risk factor for mortality.

CONCLUSIONS

MRSA is emerging in the setting of community-acquired septic arthritis. MRSA septic arthritis is more likely to develop in the elderly and in healthcare-associated infections than MSSA septic arthritis.

Increased occurrence of native septic arthritis in adult cirrhotic patients: a population-based three-year follow-up study in Taiwan

INTRODUCTION

Due to impairment of immunity and metabolism, cirrhotic patients are prone to infection, osteoporosis, and osteonecrosis. However, it is unknown if cirrhotic patients are prone to native septic arthritis (NSA).

AIM

To assess the occurrence of NSA between cirrhotic and non-cirrhotic patients.

MATERIAL AND METHODS

We used the Taiwan National Health Insurance Database to enrol 35,106 cirrhotic patients and 33,457 non-cirrhotic patients from January 1, 2004 to December 31, 2004. The medical record of each patient was individually followed for a 3-year period.

RESULTS

There were 341 (0.5%) patients having NSA in a follow-up period of 3 years: 214 cirrhotic and 127 non-cirrhotic patients. The incidence density of hospitalisation for NSA was 2.03 episodes/1000 person-years in cirrhotic patients, and 1.27 episodes/1000 person-years in non-cirrhotic patients. After adjustment for age, gender, and other comorbid disorders, Cox's regression analysis showed that cirrhotic patients had a higher occurrence of NSA than non-cirrhotic patients(hazard ratio (HR) = 1.51, 95% confidence interval (CI) = 1.19-1.90; p = 0.001). The patients with complicated cirrhosis were more prone to have NSA than those with non-complicated cirrhosis (HR = 1.46, 95% CI = 1.09-1.96, p = 0.011).

CONCLUSIONS

This analysis demonstrates that cirrhotic patients have a higher risk of NSA, particularly those with complicated cirrhosis.

Disseminated Aspergillus flavus following septic arthritis in an immunocompetent patient: a case report

BACKGROUND

Aspergillosis is a rare cause of osteomyelitis and septic arthritis. Aspergillus osteomyelitis is a debilitating infection affecting both immunocompromised and immunocompetent patients. It is associated with a high incidence of morbidity and mortality. Infection with Aspergillus flavus species in the knee has been very rarely seen in the past.

CASE PRESENTATION

We present a case of septic arthritis of the knee in an Indian patient secondary to infection with Aspergillus flavus, which was earlier managed as a case of tuberculosis based on the endemicity of the condition, later leading to disseminated aspergillosis. There was no clinical feature or investigation suggesting immunocompromised state. Following knee arthrotomy, Aspergillus flavus was isolated and patient was subsequently managed with antifungals leading to recovery after three months.

CONCLUSIONS

Disseminated aspergillosis can mimic tuberculosis both clinically and radiologically. Though fungal infections affect joints rarely but they must always be ruled out to avoid later complications.

Simultaneous bilateral septic arthritis of the knee after intraarticular steroid injection: A clinical report

Osteoarthritis of knee is one of the common problems in elderly population. Intraarticular corticosteroid injection is a conservative management modality in osteoarthritis of knee. Septic arthritis is an infective complication of intraarticular corticosteroid injection. Septic arthritis in rheumatoid arthritis patients have worse prognosis because of delay in diagnosis. A higher rate of infectious complications following intraarticular injection is expected in immunocompromised and rheumatoid patients. We would like to report an extremely rare case of simultaneous bilateral knee septic arthritis after bilateral knee intraarticular steroid injection in a rheumatoid arthritis patient. Patient was treated successfully with multiple bilateral knee arthroscopic washouts and long-term intravenous antibiotics. This case report emphasizes the increased risk of infection in rheumatoid arthritis patients and a risk benefit assessment on individual basis before carrying out intraarticular steroid injection. Patient should be aware of this increased risk of infection.

Septic arthritis in ACL reconstruction surgery with hamstring autografts. Eleven years of experience

BACKGROUND

Knee joint infection after ACL reconstruction is a rare complication with a low reported incidence, but the consequences can be devastating. The purpose of the study was to determine the incidence of septic arthritis after primary ACL reconstruction with hamstring auto-graft and the risk factors that may be associated.

METHOD

A retrospective study of all primary ACL reconstruction from January 2000 to May 2011. Electronic medical records were reviewed to determine the number of infections, operating time, associated procedure, time of presentation after surgery, infection treatment, microbiological cultures and graft retention. At the end of the follow-up (18-108months) a functional assessment of all the infected patients was performed using the Lysholm score with the Lysholm score.

RESULTS

We analyzed 1564 cases of primary ACL reconstruction with hamstring autograft, of which seven cases were diagnosed with postoperative joint infection (incidence rate of 0.45%). The infectious agent most frequently isolated was a coagulase-negative Staphylococcus. Neither intraoperative factors nor age correlated with the development of the infection. The average Lysholm score was 95 points (range 89-100 points). All but two patients retained their reconstructed ACL. The results of the five patients in which the graft was preserved were significantly better than the two patients that had their grafts removed (p=0.03).

CONCLUSION

We conclude that septic arthritis post ACL reconstruction has a low incidence rate, which if handled at an early stage allows the patients a satisfactory return to their previous activities. Graft retention is important to obtain better functional results.

LEVEL OF EVIDENCE

IV.

Pneumococcal septic arthritis in adults: clinical analysis and review

BACKGROUND

Septic arthritis (SA) is a rheumatological emergency that can lead to rapid joint destruction and irreversible loss of function. The most common pathogen causing SA is Staphylococcus aureus which is responsible for 37-65% of cases. Streptococcus pneumoniae is traditionally described as an uncommon cause of SA of a native joint. The objective of our study was to analyse clinical characteristics, treatment, and outcome of all cases of pneumococcal septic arthritis treated in our institution, and to compare them with other series published in the literature.

MATERIALS AND METHODS

We conducted a retrospective study of pneumococcal SA identified among all cases of SA diagnosed in a teaching hospital of one thousand beds between 2004 and 2009. Diagnosis was based on culture of joint liquid or by the presence of pneumococcal bacteraemia and purulent (more than 50 000/mm(3) white blood cells with more than 90% neutrophils) joint fluid aspiration.

RESULTS

Among 266 cases of SA, nine patients (3·3%) were diagnosed as having pneumococcal SA. The median age was 75 years. The main affected joint was the knee (7/9). No patient had more than one joint involved. Four patients suffered from concomitant pneumonia. Joint culture and blood cultures were positive in 7/9 and 5/9, respectively. Median (range) length of stay was 18 days (3-47 days). One patient with associated pneumococcal bacteraemia died 19 days after admission. Seven patients recovered completely.

CONCLUSIONS

Streptococcus pneumoniae is now being increasingly recognized as a common agent of SA. This organism is frequently associated with pneumococcal pneumonia or bacteraemia, particularly in patients with advanced age and comorbidities. Direct inoculation of joint fluid into blood culture medium BACTEC system increases the probability of microbiological diagnosis. The prognosis is usually favourable if the disease is promptly recognized and treated (antibiotic therapy combined with joint drainage).

Invasion of endothelial cells and arthritogenic potential of endocarditis-associated Corynebacterium diphtheriae

Although infection by Corynebacterium diphtheriae is a model of extracellular mucosal pathogenesis, different clones have been also associated with invasive infections such as sepsis, endocarditis, septic arthritis and osteomyelitis. The mechanisms that promote C. diphtheriae infection and haematogenic dissemination need further investigation. In this study we evaluated the association and invasion mechanisms with human umbilical vein endothelial cells (HUVECs) and experimental arthritis in mice of endocarditis-associated strains and control non-invasive strains. C. diphtheriae strains were able to adhere to and invade HUVECs at different levels. The endocarditis-associated strains displayed an aggregative adherence pattern and a higher number of internalized viable cells in HUVECs. Transmission electron microscopy (TEM) analysis revealed intracellular bacteria free in the cytoplasm and/or contained in a host-membrane-confined compartment as single micro-organisms. Data showed bacterial internalization dependent on microfilament and microtubule stability and involvement of protein phosphorylation in the HUVEC signalling pathway. A high number of affected joints and high arthritis index in addition to the histopathological features indicated a strain-dependent ability of C. diphtheriae to cause severe polyarthritis. A correlation between the arthritis index and increased systemic levels of IL-6 and TNF-α was observed for endocarditis-associated strains. In conclusion, higher incidence of potential mechanisms by which C. diphtheriae may access the bloodstream through the endothelial barrier and stimulate the production of pro-inflammatory cytokines such as IL-6 and TNF-α, in addition to the ability to affect the joints and induce arthritis through haematogenic spread are thought to be related to the pathogenesis of endocarditis-associated strains.

Effects of heme oxygenase-1 on bacterial antigen-induced articular chondrocyte catabolism in vitro

This study tested the hypothesis that heme oxygenase-1 (HO-1) expression counteracts bacterial antigen-induced catabolic metabolism in human articular chondrocytes. HO-1 expression was induced in chondrocytes by the iron-containing porphoryin, hemin. Anti-catabolic and anti-apoptotic effects of HO-1 expression were evaluated following bacterial antigen (lipopolysaccharides, LPS) activation of chondrocytes by quantification of cytokine and cartilage matrix protein expression. Effects of HO-1 over-expression on chondrocyte matrix metabolism were evaluated using plasmid-driven protein synthesis. Hemin increased HO-1 expression and LPS increased interleukin-1beta and interleukin-6 gene and protein expression in chondrocytes. Hemin-induced HO-1 decreased LPS-induced interleukin-1beta and interleukin-6 gene and protein expression. Increased HO-1 expression partially reversed LPS-suppression of aggrecan and type II collagen gene expression and suppressed LPS-induced gene expression of IL-6, inducible nitric oxide synthase (iNOS), matrix metalloproteinases (MMPs), and IL-1beta. HO-1 induction was inversely correlated with LPS-induced chondrocyte apoptosis. HO-1 over-expression in chondrocytes decreased matrix protein gene expression. With LPS activation, increased HO-1 expression decreased chondrocyte catabolism, partially reversed LPS-dependent inhibition of cartilage matrix protein expression and protected against apoptosis. Without LPS, hemin-induced HO-1 and plasmid-based over-expression of HO-1 inhibited cartilage matrix gene expression. The results suggest that elevated HO-1 expression in chondrocytes is protective of cartilage in inflamed joints but may otherwise suppress matrix turn over.

Knee joint infection after ACL reconstruction: prevalence, management and functional outcomes

PURPOSE

Septic arthritis after an ACL reconstruction is a rare but serious complication. Functional outcomes of these patients have not been studied in depth in large series. The aim of this study was to determine the prevalence and management of knee joint infection following ACL reconstruction and to assess the functional outcomes.

METHODS

A retrospective assessment of knee joint infections occurring after arthroscopically assisted ACL reconstructions done from 2006 to 2009 in two hospitals by the same surgical team is presented. Patients with signs and symptoms of joint infection along with blood and synovial effusion laboratory parameters suggestive of infection were considered as septic arthritis. All the patients were treated with antibiotic therapy according to antibiotic sensitivity and had at least one arthroscopic lavage. Final outcomes were assessed and compared with a control group using the KT-1000 arthrometer, functional testing and radiological examination.

RESULTS

Fifteen (1.8 %) out of 810 patients included in the study were considered as a joint infection. Microbiology showed that coagulase-negative Staphylococcus was present in 10 patients, Staphylococcus Aureus in three patients (2 MSSA and 1 MRSA) and Propinebacterium sp. in one patient. In one patient, the micro-organism was unknown. At a mean follow-up of 39.3 ± 13 months, the Lysholm score was 77.7 ± 15.3, the IKDC score was 70.4 ± 19.5, and the KT-1000 compared to the non-injured contralateral knee showed a mean difference of 1.3 ± 2 mm. Functional outcomes in the control group were slightly better than those obtained in the infected group (Lysholm score; 90.7 ± 9.4, p = 0.007. IKDC score; 86.6 ± 6.8, p = 0.004). All but one patient retained their reconstructed ACL.

CONCLUSIONS

The prevalence of septic arthritis after an ACL reconstruction in this series was 1.8 %. Arthroscopic lavages along with antibiotic treatment led us to preserve all but one graft. Functional outcomes in the infected patients were not as good as those obtained in patients without infection.

Differential arthritogenicity of Staphylococcus aureus strains isolated from biological samples

BACKGROUND

Staphylococcus aureus is the most common agent of septic arthritis that is a severe, rapidly progressive and destructive joint disease. Superantigens produced by S. aureus are considered the major arthritogenic factors. In this study, we compared the arthritogenic potential of five superantigen-producing staphylococcal strains.

METHODS

Male C57BL/6 mice were intravenously infected with ATCC 19095 SEC+, N315 ST5 TSST-1+, S-70 TSST-1+, ATCC 51650 TSST-1+ and ATCC 13565 SEA+ strains. Clinical parameters as body weight, arthritis incidence and clinical score were daily evaluated. Joint histopathological analysis and spleen cytokine production were evaluated at the 14th day after infection.

RESULTS

Weight loss was observed in all infected mice. ATCC 19095 SEC+, N315 ST5 TSST-1+ and S-70 TSST-1+ were arthritogenic, being the highest scores observed in ATCC 19095 SEC+ infected mice. Intermediate and lower clinical scores were observed in N315 ST5 TSST-1+ and S-70 TSST-1+ infected mice, respectively. The ATCC 13565 SEA+ strain caused death of 85% of the animals after 48 h. Arthritis triggered by the ATCC 19095 SEC+ strain was characterized by accentuated synovial hyperplasia, inflammation, pannus formation, cartilage destruction and bone erosion. Similar joint alterations were found in N315 ST5 TSST-1+ infected mice, however they were strikingly more discrete. Only minor synovial proliferation and inflammation were triggered by the S-70 TSST-1+ strain. The lowest levels of TNF-α, IL-6 and IL-17 production in response to S. aureus stimulation were found in cultures from mice infected with the less arthritogenic strains (S-70 TSST-1+ and ATCC 51650 TSST-1+). The highest production of IL-17 was detected in mice infected with the most arthritogenic strains (ATCC 19095 SEC+ and N315 ST5 TSST-1+).

CONCLUSIONS

Together these results demonstrated that S. aureus strains, isolated from biological samples, were able to induce a typical septic arthritis in mice. These results also suggest that the variable arthritogenicity of these strains was, at least in part, related to their differential ability to induce IL-17 production.

Incidence and bacteriologic causes of septic arthritis in a general hospital in Saudi Arabia

BACKGROUND AND OBJECTIVES

Since data on the incidence and etiology of septic arthritis in Saudi Arabia is sparse, we analyzed the incidence and bacterial etiology of septic arthritis in a general hospital in Saudi Arabia.

DESIGN AND SETTINGS

Observational study of all hospitalized patients with native joint septic arthritis from 2005 to 2010.

PATIENTS AND METHODS

We specifically collected data on demography, joint(s) affected, synovial fluid gram stain and culture, and blood culture. We also included the initial antimicrobial agents, length of stay (LOS) and any surgical interventions. Data were analyzed using simple descriptive statistics.

RESULTS

There were 58 cases of native joint septic arthritis with an annual incidence rate of 0.2-0.8 per 1000 discharges. There were 31 (53.4%) males and 27 (46.6%) females with a mean (SD) age of 44.2 (29.3) years. There were 18 (25.8%) children < 18 years of age. The most frequently affected joints were the knee (28, 48.3%), ankle (7, 12.1%), elbow (6, 10.3%), and shoulder (4, 6.9%). Of the synovial cultures, 17 (29.3%) were nega.tive and the most commonly isolated organism was methicillin-susceptible Staphylococcus aureus (16, 27.6%). Blood cultures were negative in 38 cases (67.8%) and positive in the remaining 32%. The most common or.ganism from blood cultures was S aureus (12.5%). There was no difference in the rate of positive synovial fluid cultures between children and adults (65% vs 82.4%, P=.22), but children were more likely to grow S aureus (53%) than adults (20%) (P=.024).

CONCLUSIONS

Septic arthritis is an uncommon disease in the study population and the most common organism is S aureus.

Gentamicin in combination with ascorbic acid regulates the severity of Staphylococcus aureus infection-induced septic arthritis in mice

To study the effects of gentamicin in combination with ascorbic acid on septic arthritis, mice were infected with Staphylococcus aureus (S. aureus) and treated with gentamicin, which was given at 5 mg/kg after 24 h of infection, followed by ascorbic acid, given at 20 mg/kg body weight after 2 h of gentamicin treatment. Mice were sacrificed at 3, 9, 15 days post-infection (dpi). Combined treatment of infected mice with gentamicin and ascorbic acid eradicated the bacteria from the blood, spleen and synovial tissue and showed a significant gross reduction in arthritis, reduced serum levels of tumour necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). S. aureus-infected mice have demonstrated the disturbed antioxidant status measured in terms of cellular antioxidants like reduced glutathione and antioxidant enzymes such as superoxide dismutase (SOD) and catalase. The same were ameliorated when the animals were co-treated with gentamicin along with ascorbic acid.

Primary meningococcal arthritis requiring surgical drainage

Primary meningococcal arthritis (PMA) is a relatively rare diagnosis where the role of early surgical intervention for its treatment is not well defined. We report a case of PMA in a young otherwise healthy patient who developed polyarticular joint pain secondary to Niessieria meningitidis without systemic symptoms of meningitis or meningococcemia. He underwent a prolonged course of intravenous antibiotics and serial aspirations of his shoulder. However, symptoms in his shoulder did not improve and he later underwent surgical irrigation and debridement.Intraoperatively, the patient had no signs of articular damage to his right shoulder despite prolonged clinically symptomatic disease. Six weeks after surgery, he has regained normal strength and full range of motion without any deficits.Nonoperative management of PMA is frequently, but not invariably, successful. We report a patient with this diagnosis who ultimately needed surgical evacuation of his shoulder joint to achieve resolution of his symptoms.

[Joint infections. Known facts and new trends]

Acute septic arthritis is a surgical emergency because rapid septic destruction of articular cartilage can lead to impairment or even loss of joint function. Diagnosis consists of patient history, clinical examination, laboratory results, (sonography- guided) joint aspiration and radiography. Emergency therapy is based on arthroscopic or open joint debridement and lavage combined with systemic antibiotic therapy. No data are available for the recommendation of local antibiotics but antiseptic solutions are not recommended because of cartilage damage. New trends in diagnostics are positron emission tomography/computed tomography (PET/CT), urine sticks for analysis of joint fluid and molecular pathology. Chronic joint empyema is more diagnostically demanding and is difficult to treat. In cases of necrotic and infected articular cartilage, joint resection has to be performed for quiescence of infection. Options following successful treatment of empyema are arthroplasty, arthrodesis or permanent resection.

Acute hematogenous septic arthritis of the knee in adults

PURPOSE OF STUDY

To evaluate the factors associated with acute hematogenous septic arthritis of the knee in adults and to assess the outcome after open knee arthrotomy.

METHODS

We performed a prospective evaluation of 26 adult patients with acute nongonococcal septic arthritis of the knee presenting within 7 days. All patients underwent open knee arthrotomy, and final evaluation by means of Knee society score of the affected knee was compared with the contra lateral normal knee.

RESULTS

The average duration of symptoms at the time of presentation was 3.9 days. Staphylococcus aureus was the commonest bacteria isolated in 17 (65.4 %) patients. The average duration of follow-up in our study was 18.5 months. In our study, Knee society score decreases as the age of the patient advances (P < 0.05) and also it was found to be low (P < 0.05) in the affected knee as compared to contra lateral normal knee.

CONCLUSION

Our study shows that age of the patient at presentation is critical as it shows significant reduction in knee score. This explains that the septic arthritis may contribute to the progression of age-related degeneration of the knee joint. There appears to be no definite contributing factors or conditions associated with acute hematogenous septic arthritis of the knee in adults, although further study may be warranted regarding this matter.

Computational structural and functional analysis of hypothetical proteins of Staphylococcus aureus

Genome sequencing projects has led to an explosion of large amount of gene products in which many are of hypothetical proteins with unknown function. Analyzing and annotating the functions of hypothetical proteins is important in Staphylococcus aureus which is a pathogenic bacterium that cause multiple types of diseases by infecting various sites in humans and animals. In this study, ten hypothetical proteins of Staphylococcus aureus were retrieved from NCBI and analyzed for their structural and functional characteristics by using various bioinformatics tools and databases. The analysis revealed that some of them possessed functionally important domains and families and protein-protein interacting partners which were ABC transporter ATP-binding protein, Multiple Antibiotic Resistance (MAR) family, export proteins, Helix-Turn-helix domains, arsenate reductase, elongation factor, ribosomal proteins, Cysteine protease precursor, Type-I restriction endonuclease enzyme and plasmid recombination enzyme which might have the same functions in hypothetical proteins. The structural prediction of those proteins and binding sites prediction have been done which would be useful in docking studies for aiding in the drug discovery.

Beyond the definitions of the phenotypic complications of sickle cell disease: an update on management

The sickle hemoglobin is an abnormal hemoglobin due to point mutation (GAG → GTG) in exon 1 of the β globin gene resulting in the substitution of glutamic acid by valine at position 6 of the β globin polypeptide chain. Although the molecular lesion is a single-point mutation, the sickle gene is pleiotropic in nature causing multiple phenotypic expressions that constitute the various complications of sickle cell disease in general and sickle cell anemia in particular. The disease itself is chronic in nature but many of its complications are acute such as the recurrent acute painful crises (its hallmark), acute chest syndrome, and priapism. These complications vary considerably among patients, in the same patient with time, among countries and with age and sex. To date, there is no well-established consensus among providers on the management of the complications of sickle cell disease due in part to lack of evidence and in part to differences in the experience of providers. It is the aim of this paper to review available current approaches to manage the major complications of sickle cell disease. We hope that this will establish another preliminary forum among providers that may eventually lead the way to better outcomes.

A Study on Hand Contamination and Hand Washing Practices among Medical Students

Harmful microorganisms can be transferred to hands from contaminated surfaces people come into contact in daily life. Contaminated hands can transmit disease to one self as well as to others. A study was done to determine the extent to which hand hygiene practices and toilet door knobs contribute to the bacterial load of hands of toilet users in a medical school. Swabs were taken from a randomly selected sample of 60 medical students for bacterial count from both hands before and after toilet use and from door knobs of six toilets. Only 40 (66.7%) claimed they washed hands with soap. Significantly more females (83%) used soap to wash hands compared to males (50%). Bacterial load in the hands of both males and females showed an increase after toilet use. The increase was significant among male students. The dominant hand had a significantly higher bacterial load than the other. The mean bacterial load of male toilet door knobs (12 CFU/cm2) were significantly higher than of female toilet door knobs (2.5 CFU/cm2) (P<0.05). Staphylococcus aureus was isolated from the hands of 21 students. Toilets and washrooms should be designed so as to eliminate the sources of contamination of the hands.

The amber theory of Lyme arthritis: initial description and clinical implications

Lyme arthritis differs in many respects from other bacterial causes of arthritis. Based on an observation made for a patient with Lyme arthritis, we propose that the pathogenesis of joint swelling in Lyme arthritis is due to the introduction into the joint space of non-viable spirochetes or more likely spirochetal debris enmeshed in a host-derived fibrinous or collagenous matrix. This "amber" hypothesis can account for the clinical and laboratory features of Lyme arthritis and is amenable to experimental validation. Validation would directly impact the clinical management of patients with Lyme arthritis.

Retrospective investigation of prognostic indicators for adult horses with infection of a synovial structure

OBJECTIVE

To investigate predictors of survival and athletic function in adult horses with infection of a synovial structure.

HYPOTHESES

Increasing duration from contamination to referral, bone or tendon involvement and positive microbial culture decreases short-term survival. Synovitis and/or sepsis at 5 days post-admission and involvement of Staphylococcus spp. decreases long-term athletic function.

DESIGN

Retrospective study.

METHODS

Records over 4 years of adult horses with synovial sepsis were reviewed. A two-tailed Fisher's exact test, Mann-Whitney U test or t-test was used to examine whether variables were predictive of short-term survival and long-term athletic function.

RESULTS

During the study period 75 horses underwent treatment for infection of 93 synovial structures. Short-term survival was 84% (63/75) and 54% (30/56) of horses returned to athletic function. Of the variables measured at admission, duration from contamination to referral did not affect survival, whereas evidence of bone or tendon involvement decreased survival and athletic function. Of the variables available during treatment, abnormal synovial fluid at 4-6 days post-admission and positive microbial culture reduced athletic function. Staphylococcal infection was associated with persistent sepsis.

CONCLUSIONS

Of the variables available at presentation, only evidence of bone or tendon involvement negatively affected survival and athletic function. During treatment of synovial sepsis, analysis of synovial fluid at 4-6 days and bacterial culture results have prognostic value.

Strain-dependent arthritogenic potential of the zoonotic pathogen Corynebacterium ulcerans

During the last decade the majority of diphtheria cases in Europe had Corynebacterium ulcerans as the etiologic agent with dogs and cats as the reservoir hosts. However, little has been documented about the virulence factors of this zoonotic pathogen. To set up an in vivo experimental C. ulcerans infection model, conventional Swiss Webster mice were intravenously infected with different doses (from 1 × 10(7) to 5 × 10(9) bacteria per mouse) of C. ulcerans strains, namely 809 (from human lower respiratory tract), BR-AD22 (from asymptomatic dog nares) and CDC-KC279. Mortality rates were demonstrated by LD(50) values ranging from 1.9 × 10(8) to 1.3 × 10(9). Viable bacteria were recovered from blood, kidneys, liver, spleen and joints. For CDC-KC279 and 809 strains (2 × 10(8)mL(-1)) approximately 85% and 72% of animals with articular lesions were observed, respectively; BR-AD22-infected mice showed no signs of arthritis. CDC-KC279 and 809 strains exhibited higher arthritogenic potential when compared to the homologous toxigenic (ATCC27012) and non-toxigenic (ATCC27010) strains of Corynebacterium diphtheriae. A high number of affected joints and arthritis index in addition to the histopathological features, including subcutaneous edema, inflammatory infiltrate, damage to bone tissue and synoviocyte hypertrophy, indicated a strain-dependent ability of C. ulcerans strains to cause severe polyarthritis. A correlation between the arthritis index and systemic levels of IL-6 and TNF-α was observed for C. ulcerans strains, with the exception of the non-arthritogenic BR-AD22 strain. In conclusion, C. ulcerans revealed a strain-dependent arthritogenic potential independent of DNAse, PLD and diphtheria toxin production.

TMJ ankylosis after neonatal septic arthritis: literature review and two case reports

Ankylosis of the temporomandibular joint (TMJ) can be a result of several causes such as trauma, degenerative changes, infection, and space-occupying lesion. When occurring during early childhood, it can result in severe functional disability and facial deformity. Septic arthritis is an uncommon disease associated with systemic and local factors being most commonly caused by Staphylococcus aureus, Neisseria gonorrhoeae, and Haemophilus influenzae. This paper presents two unusual cases of TMJ ankylosis following neonatal infections treated surgically and does a literature review about the topic.

Septic arthritis of the hip in adults with sickle cell anemia

Although the presence of osteonecrotic bone is known to make joints more prone to infection, acute septic joint in hip osteonecrosis has not frequently been reported in adults with sickle cell disease. The clinical features at the time of admission, imaging findings suggesting the diagnosis, modes of treatment and sequelae of septic arthritis of twenty-four hip joints with osteonecrosis in patients with sickle cell disease were studied retrospectively over a 25-years period. This study evaluated also the complications, the efficiency and the risk of total hip arthroplasty in these patients. Most patients were in the third decade of life. Staphylococcus and Gram negative infection predominated. Treatment was first conservative but most of the patients needed surgery to treat infection and sequelae related to infection. A total hip arthroplasty was performed later in twenty joints. No deaths were observed, but complications occurred. Twenty of the patients in our study underwent delayed total hip arthroplasties following repeated aspirations of the joint and intravenous antibiotics. With an experienced surgical and medical team and multidisciplinary management of these patients undergoing total hip arthroplasty after hip infection, our rate of complications was acceptable.

Lyme arthritis in children presenting with joint effusions

BACKGROUND

The present study was designed to evaluate the prevalence of Lyme arthritis in children who had a joint aspiration at a tertiary care children's hospital in an endemic area and to identify clinical factors useful to differentiate Lyme arthritis from septic arthritis at the time of the initial presentation.

METHODS

The records of all children with an age of eighteen years or less who were managed with aspiration for joint effusions at our institution from 1992 to 2009 were reviewed. Data collection included a review of aspirates; an analysis of cell count, culture results, and hematological inflammatory markers; and a review of surgical intervention.

RESULTS

A total of 506 joint aspirations were analyzed. One hundred and fifteen aspirations were excluded. In the remaining group of 391 patients, 123 (31%) were subsequently diagnosed with Lyme arthritis. Fifty-one patients had culture-positive septic arthritis. The two cohorts were significantly different in terms of the presence of a fever of >101.5°F (>40.6°C) at the time of presentation, the refusal to bear weight, the peripheral white blood-cell count, and joint fluid cell count. The erythrocyte sedimentation rate and the C-reactive protein level were not significantly different between the two cohorts. Multivariate analysis demonstrated that refusal to bear weight was the strongest predictor of the diagnosis of septic arthritis over Lyme arthritis.

CONCLUSIONS

For any child presenting with a joint effusion in a Lyme-endemic area of the Northeastern United States, the likely prevalence of Lyme arthritis is 31% overall and 45% in the presence of knee effusion. Children with joint effusions resulting from Lyme disease are more likely to have knee involvement, a lower peripheral white blood-cell count, and a lower joint fluid cell count, and they are less likely to have fever or complete refusal to bear weight, when compared with children with septic arthritis.

The catabolic role of toll-like receptor 2 (TLR-2) mediated by the NF-κB pathway in septic arthritis

Toll-like receptors (TLRs) are involved in mediating cell activation on stimulation with microbial components. Our objective was to investigate the role of TLR-2 mediated by the NF-κB pathway in septic arthritic chondrocytes. TLR-1, -2, and -6 mRNA expression levels were investigated in septic and normal chondrocytes using real-time reverse transcription-PCR. TLR-2 and MMP-13 mRNA and protein levels were measured using real-time PCR and Western blot analysis, respectively. Blocking TLR-2 mRNA expression was performed using small interfering RNA (siRNA) against TLR-2 and subsequently MMP-3, MMP-13, IL-1β, and IL-6 mRNA levels, as well as p65 NF-κB, IkBα, and MMP-13 protein levels were evaluated using real-time PCR and Western blot analysis. IL-6 protein levels were measured using ELISA assay. We observed that TLR-1, -2, and -6 mRNA expression levels were significantly higher in septic compared to normal chondrocytes. MMP-13 mRNA and protein expressions were also significantly upregulated in septic arthritic cartilage. Blocking TLR-2 mRNA expression in septic chondrocytes resulted in significant increase of inactivated nonphosphorylated p65 NF-κB and IkBα protein levels and reduction in MMP-13, IL-1β, and IL-6 expression. Our findings suggest the pro-inflammatory and catabolic role of TLR-2 mediated by the NF-κB pathway in septic arthritis. Modulation of TLR-mediated signaling may be a potential therapeutic strategy for the prevention of postinfectious cartilage degradation in articular joints.

Septic arthritis in adults with sickle cell disease often is associated with osteomyelitis or osteonecrosis

BACKGROUND

Septic arthritis is a known complication of sickle cell disease (SCD) in children, and the association with osteomyelitis and osteonecrosis has been described. However, it is unclear whether this association applies to adults.

QUESTIONS/PURPOSES

We therefore asked whether septic arthritis is a frequent complication in adults with SCD and whether it also is associated with osteomyelitis or osteonecrosis.

METHODS

We retrospectively reviewed the charts of 2000 consecutive adult patients diagnosed with SCD and recorded symptoms, select findings during physical examination, laboratory data, and select radiographic CT, and MRI observations.

RESULTS

Fifty-nine of the 2000 patients (3%) had septic arthritis, 56 of the 59 patients had hemoglobin SS. Thirty-six of the 59 infections (61%) were in the hip. The most frequent findings were pain, swelling, fever greater than 38.2 degrees C (71% of cases), a leukocyte count exceeding 15,000/mm(3) (range, 7900-32,300/mm(3)), a Westergren sedimentation rate greater than 24 mm/hour, and C-reactive protein exceeding 20 mg/L. Cultures were positive in 96% of the joint aspirates. Staphylococcus and Gram-negative infection predominated; no patients had Salmonella joint infections. Preexisting factors of bacterial arthritis included osteonecrosis (29 patients) and osteomyelitis (37 cases) in childhood. Diabetes, rheumatoid arthritis, glucocorticoids, and immunoparesis related to medical treatment by hydroxyurea were associated comorbidities. CT and MRI confirmed the diagnosis of associated osteonecrosis or osteomyelitis and allowed joint aspiration and detection of soft tissue abscess.

CONCLUSIONS

The incidence of septic arthritis in adults with SCD is low, but often is associated with osteomyelitis or osteonecrosis.

LEVEL OF EVIDENCE

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

A comparison of early versus late conversion from intravenous to oral therapy in the treatment of septic arthritis

BACKGROUND

Clinical outcomes of children with bacterial septic arthritis, common in the pediatric age group, are often satisfactory with early recognition, prompt surgical drainage, and appropriate antibiotic therapy. However, the optimal duration and route of antibiotic administration for treatment of septic arthritis continues to be debated, as traditional treatment favored longer intravenous (IV) therapies yet oral regimens are increasingly available that are more cost effective, safe and produce satisfactory disease resolution.

METHODS

Records of 186 patients from two children's hospitals, one that was thought to convert from IV to oral antibiotic therapy considerably earlier than the other, treated between 1985 and 1995 for bacterial septic arthritis were reviewed. Patients with concurrent osteomyelitis were excluded.

RESULTS

Patients at Hospital #1 were converted to oral antibiotics after 7.4+/-7.4 days of IV antibiotic therapy and at Hospital #2 after 18.6+/-13.6 (P<0.001) days of IV therapy. Both groups received an average of four weeks of total antibiotic treatment. There was similar time to defervescence (2.4+/-3.2 d vs. 2.4+/-3.8 d, P>0.05) and to normalization of erythrocyte sedimentation rate (35.7+/-19.7 d vs. 33.8+/-44.9 d, P>0.05) in the patients converted to oral therapy early compared to those converted late. One case of mild avascular necrosis with no clinical disability developed in a patient from Hospital #2.

CONCLUSIONS

We conclude that the clinical outcome in patients with septic arthritis converted to oral antibiotic therapy early in their treatment based on defined criteria was similar to those converted late.

IL-4 deficiency decreases mortality but increases severity of arthritis in experimental group B Streptococcus infection

IL-4 is an anti-inflammatory cytokine that inhibits the onset and severity in different experimental arthritis models. Group B streptococci (GBS) have been recognized as an ever-growing cause of serious invasive infections in nonpregnant adults. Septic arthritis is a clinical manifestation of GBS infection. To investigate the role of IL-4 in experimental GBS infection, IL-4 deficient or competent mice were inoculated with 1 × 10⁷ GBS/mouse. Mortality, appearance of arthritis, GBS growth in the organs, and local and systemic cytokine and chemokine production were examined. IL-4−/− mice showed lower mortality rates but increased severity of arthritis and exhibited a lower microbial load in blood, kidneys, and joints than wt mice. Increased local levels of IL-1 β, IL-6, TNF-α, MIP-1α, and MIP-2 accompanied the more severe arthritis in IL-4−/− mice. Our results suggest a detrimental role of IL-4 in GBS sepsis, whereas it plays a beneficial effect on GBS-induced arthritis.

Treatment of neonatal septic arthritis sequelae of hip: a case report

INTRODUCTION

The most serious complication of the septic arthritis of the hip in childhood and especially in newborns is the avascular necrosis of the femoral head. The aim of the study was evaluation of residual deformity after neonatal septic arthritis of the hip in a boy aged thirteen years.

CASE PRESENTATION

A 13-year-old, white male, was operatively treated by intertrochanteric osteotomy of valgisation, anterotation and extension at age of twelve years because of leg length discrepancy, changes in the femoral neck, coxa vara, plana and breva. It was delay in diagnosis and failure to begin treatment promptly in the neonatal period.

CONCLUSION

Valgus intertrochanteric osteotomy of the femur, moves the greater trochanter distally and laterally, tensioning the abductors muscles and improving their leverage.