How Common is MRSA in Adult Septic Arthritis?

Orthopedic Articular and Periarticular Joint Infections

Acute nontraumatic joint pain has an extensive differential. Emergency physicians must be adept at identifying limb and potentially life-threatening infection. Chief among these is septic arthritis. In addition to knowing how these joint infections typically present, clinicians need to be aware of host and pathogen factors that can lead to more insidious presentations and how these factors impact the interpretation of diagnostic tests.

Prevalence, antimicrobial susceptibility pattern and multidrug resistance of methicillin-resistant Staphylococcus aureus isolated from clinical samples at a tertiary care teaching hospital: an observational, cross-sectional study from the Himalayan country, Nepal

OBJECTIVE

We sought to determine the prevalence and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus (MRSA) isolated from the clinical samples at a tertiary care hospital in Nepal.

METHODS

Cross-sectional, observational study design.

STUDY SETTING

The study was carried out at a tertiary care facility, the largest public hospital, Tribhuvan University Teaching Hospital (TUTH), Nepal.

PARTICIPANTS

A total of 7433 clinical samples from hospital inpatients and outpatients available in the TUTH microbiology laboratory were examined. The study included clinical samples from the patients of either sex and across all age groups that had been clinically determined to have S. aureus infections.

RESULTS

Of 7433 clinical samples analysed, S. aureus was recovered from 499 (6.71%). The prevalence of MRSA was discovered to be 26.4% (95% CI 21.6% to 30.4%). The major sources of MRSA were pus, 71 (18.5%). MRSA isolates encountered 100% resistance to penicillin and cloxacillin, followed by ciprofloxacin (80.5%), erythromycin (79.8%), cephalexin (64.9%), cotrimoxazole (61.1%) and clindamycin (58.5%). Chloramphenicol (17.9%), and gentamicin (27.4%), on the other hand, exhibited minimal resistance. None of the isolates were resistant to vancomycin (0.0%). Prevalence of multidrug resistance (MDR) was markedly higher in MRSA, 94.05% (95% CI 89.4% to 98.6%), compared with methicillin-sensitive S. aureus, 52.12% (95% CI 46.2% to 57.8%).

CONCLUSION

Our study indicated a high rate of MRSA and MDR-SA (Multidrug-resistant Staphylococcus aureus) prevalence in a Nepalese tertiary care hospital. Therefore, given the widespread burden of MRSA and the threat of the emergence of resistance to commonly used antibiotics, there is a need for the development, adoption and enforcement of appropriate control policies in these hospital settings. Regular surveillance, reporting mechanism as well as prudent use of antimicrobial agents are crucial to combating the progression of MDR-MRSA prevalence and antibiotic resistance.

Case Report: Septic arthritis in children caused by Streptococcus pyogenes-rational use of antibiotics

To investigate the clinical characteristics and treatment of septic arthritis caused by Streptococcus pyogenes(S. pyogenes) in children, we retrospectively analyzed the clinical data, laboratory results, treatments and outcomes of three pediatric cases of septic arthritis caused by S. pyogenes occurring from 2016-2018. The three cases of septic arthritis included 1 boy and 2 girls, aged from 2-7 years. Two patients experienced fever, and in all three cases, the affected joints showed redness, swelling, an increased local skin temperature, tenderness and restricted limb movement. At the first visit, all three cases showed a significantly increased white blood cell count [(27.68-32.02)×10⁹/mL] and a significantly increased erythrocyte sedimentation rate (113-134 mm/h). The C-reactive protein level was significantly increased in two cases (67 mg/L, 147.7 mg/L) and normal in one case. The procalcitonin level was normal in 1 case, elevated in 1 case, and undetected in 1 case. S. pyogenes isolated from cases 1 and 2 were emm1/ST28 and from case 3 was emm12/ST36. All patients were treated by abscess incision and drainage, and S. pyogenes was cultured in the abscess puncture fluid. All patients were treated with intravenous antibiotics after admission, and all patients were cured and discharged. The patients were followed up for 2 months, and their condition was improved and stable. No sequelae such as heart and kidney damage were detected. In conclusion, for children with septic arthritis, early diagnosis and timely treatment with incision and drainage followed by culture of the abscess puncture fluid are important. Once S. pyogenes infection is confirmed, β-lactam antibiotics provide effective treatment, avoiding use of broad-spectrum antibiotics.

Commensal Bacteria Augment Staphylococcus aureus septic Arthritis in a Dose-Dependent Manner

Background

Septic arthritis is considered one of the most dangerous joints diseases and is mainly caused by the Gram-positive bacterium Staphylococcus aureus (S. aureus). Human skin commensals are known to augment S. aureus infections. The aim of this study was to investigate if human commensals could augment S. aureus-induced septic arthritis.

Method

NMRI mice were inoculated with S. aureus alone or with a mixture of S. aureus together with either of the human commensal Staphylococcus epidermidis (S. epidermidis) or Streptococcus mitis (S. mitis). The clinical, radiological and histopathological changes due to septic arthritis were observed. Furthermore, the serum levels of chemokines and cytokines were assessed.

Results

Mice inoculated with a mixture of S. aureus and S. epidermidis or S. mitis developed more severe and frequent clinical arthritis compared to mice inoculated with S. aureus alone. This finding was verified pathologically and radiologically. Furthermore, the ability of mice to clear invading bacteria in the joints but not in kidneys was hampered by the bacterial mixture compared to S. aureus alone. Serum levels of monocyte chemoattractant protein 1 were elevated at the early phase of disease in the mice infected with bacterial mixture compared with ones infected with S. aureus alone. Finally, the augmentation effect in septic arthritis development by S. epidermidis was bacterial dose-dependent.

Conclusion

The commensal bacteria dose-dependently augment S. aureus-induced septic arthritis in a mouse model of septic arthritis.

Selective Activation of MST1/2 Kinases by Retinoid Agonist Adapalene Abrogates AURKA-Regulated Septic Arthritis

Septic arthritis is a chronic inflammatory disorder caused by Staphylococcus aureus invasion of host synovium, which often progresses to impairment of joint functions. Although it is known that disease progression is intricately dependent on dysregulated inflammation of the knee joint, identification of molecular events mediating such imbalance during S. aureus-induced septic arthritis still requires detailed investigation. In this article, we report that Aurora kinase A (AURKA) responsive WNT signaling activates S. aureus infection-triggered septic arthritis, which results in inflammation of the synovium. In this context, treatment with adapalene, a synthetic retinoid derivative, in a mouse model for septic arthritis shows significant reduction of proinflammatory mediators with a simultaneous decrease in bacterial burden and prevents cartilage loss. Mechanistically, adapalene treatment inhibits WNT signaling with concomitant activation of HIPPO signaling, generating alternatively activated macrophages. Collectively, we establish adapalene as a promising strategy to suppress S. aureus-induced irreversible joint damage.

Clinical Characteristics and Causative Pathogens of Infective Arthritis and Risk Factors for Gram-Negative Bacterial Infections

Background

The aim of this study was to describe the clinical and microbiological characteristics of infective arthritis and to analyze risk factors for Gram-negative bacterial infections that cause infective arthritis.

Materials and Methods

Patients admitted between 2009 - 2018 with infective arthritis in a single-tertiary hospital were evaluated retrospectively.

Results

A total of 181 patients were enrolled in this study. Of them, 135 were native joint infection patients and 46 were prosthetic joint infection patients. The most common site of infective arthritis was the knee (63.6%), followed by the shoulder (17.7%), and the hip (9.9%). The most frequently identified microorganisms were Staphylococcus aureus (51.1%), followed by Streptococci sp. (21.1%), Enterobacteriaceae (8.4%), and coagulase-negative-Staphylococci (CNS; 8.4%). Infections due to Gram-negative bacteria and fungi made up 13.7% and 3.2% of all cases, respectively. Additionally, 20% and 4.2% of the cases involved methicillin-resistant S. aureus (MRSA) and MRCNS. We found that bacteriuria, infective arthritis in the hip, and steroid use at admission are independent risk factors for Gram-negative bacterial infections.

Conclusion

Infective arthritis with methicillin-resistant microorganisms reached up to about 25% in a single-tertiary hospital in Korea. In case of suspected urinary tract infection, infective arthritis of the hip joint, or steroid use at admission time among infective arthritis patients, empirical treatment covering Gram-negative microorganisms can be considered.

Risk Factors, Screening, and Treatment Challenges in Staphylococcus aureus Native Septic Arthritis

Background

Staphylococcus aureus is the most common cause of native septic arthritis. Few studies have characterized this disease during the US opioid epidemic. The role of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening in this disease has not been elucidated. We sought to identify risk factors and outcomes for S. aureus native septic arthritis and to evaluate MRSA screening in this disease.

Methods

A retrospective cohort study of native septic arthritis patients (2012–2016) was performed. Demographics, risk factors, and outcomes were compared between Staphylococcus aureus and other native septic arthritis infections. Sensitivity, specificity, and predictive values of MRSA screening were assessed.

Results

Two hundred fifteen cases of native septic arthritis were included. S. aureus was cultured in 64% (138/215). MRSA was cultured in 23% (50/215). S. aureus was associated with injection drug use (odds ratio [OR], 4.33; 95% CI, 1.74–10.81; P = .002) and switching antibiotics (OR, 3.92; 95% CI, 1.01–21.38; P = .032). For every 10-year increase in age, the odds of S. aureus decreased (OR, 0.72; 95% CI, 0.60–0.87; P = .001). For 1-unit increases in Charlson comorbidity index score, the odds of S. aureus decreased (OR, 0.82; 95% CI, 0.73–0.91; P = .0004). MRSA screening during admission demonstrated a sensitivity of 0.59, specificity of 0.96, positive predictive value of 0.85, and negative predictive value of 0.84 for MRSA native septic arthritis.

Conclusions

The opioid epidemic may be contributing to a demographic shift in native septic arthritis to younger, healthier individuals. S. aureus native septic arthritis has unique risks, including injection drug use. MRSA screening may be useful to rule in MRSA native septic arthritis.

The Epidemiology and Outcomes of Septic Arthritis in the Maltese Islands: A Hospital-Based Retrospective Cohort Study

Objective/Aim:

Septic arthritis is an uncommon but important disease with significant morbidity and mortality, especially if inadequately managed. The aim of this epidemiological study was to identify the characteristics and outcomes of patients treated for septic arthritis at Mater Dei Hospital, Malta, over a 10-year period.

Methods:

This was a retrospective observational study. Patients diagnosed with septic arthritis between 2008 and 2018 were recruited. Cases were identified by reviewing all inhospital episodes of patients diagnosed with septic arthritis according to Newman criteria.

Results:

There were 124 cases of native joint septic arthritis and 138 of prosthetic joint infection. Cases were present amongst all age groups, with the highest incidence amongst those aged 61–70 years for both native and prosthetic infections. Fever was present in around 40% of cases. Raised white cell count was prevalent in 66.9% of native joint infections and 52.9% of prosthetic joints. Elevated C-reactive protein was overwhelmingly seen in most cases, present in 93.5% (median=159.5 mg/L; IQR=85.8–291) of native joints and 92.0% of prosthetic joint infections (median=68.7 mg/L; IQR=20.5–186). Over 55% of patients had one or more risk factors for joint sepsis, diabetes mellitus being the most prevalent clinical comorbidity (22.6% and 24.6% for native and prosthetic joint infections respectively). Synovial cultures were positive in 66% and 82% of native and prosthetic joint aspirates respectively. Staphylococcus aureus was the most commonly isolated organism from both native and prosthetic joint infection, followed by streptococcal infections in native joints and coagulase negative staphylococci and gram-negative infections in prosthetic joints. Fifteen deaths were directly attributed to joint sepsis.

Conclusion:

Absence of fever and elevated white cell count does not exclude the diagnosis. The mortality rate due to septic arthritis in this cohort of patients was found to be 5.7%. All deaths occurred in elderly patients with clinical comorbidities suggesting that this group is at highest risk.

Trends in antimicrobial resistance among bacteria causing septic arthritis in adults in a single center: A 15-years retrospective analysis

Septic arthritis (SA) is commonly associated with Staphylococcal or Streptococcal infections. Overtime, there has been a global increase in the distribution of antimicrobial resistance within both Gram-positive bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative bacteria such as extended-spectrum beta-lactamase (ESBL) positive Enterobacteriacea. The aim of this study was to determine whether this change in epidemiology similarly affected the distribution of resistant pathogens causing SA. The study was conducted at the Shaare Zedek Medical Center in Jerusalem, Israel. All adult patients diagnosed with SA during 2002-2016 were included in the cohort. Antimicrobial resistance trends were examined over three periods: 2002-2009, 2010-2013, and 2014-2016. Of 85 patients with SA, mean age of patients was 66.8 (± 20.3) years, with male predominance (n = 62, 66%). Most SA cases involved native knee joints and more than 85% (n = 80) were acquired in the community. The most common isolates were S. aureus (n = 38, 45%) and beta-hemolytic streptococci (n = 13, 15%). MRSA SA was diagnosed in 8% of all SA cases (n = 7). An increasing, although non-significant trend in MRSA SA was observed during the study period (p = 0.3). Gram-negative infections were uncommon (n = 14). No ESBL-positive or carbapenem-resistant Enterobacteriacea were detected. Over a 15-year study period, no significant increase in resistant pathogens causing SA was observed. In the era of antibiotic stewardship, these results strengthen our practice of administering narrow-spectrum antimicrobials empirically for SA. However, our findings cannot be generalized to regions with higher rates of MRSA in the community.

Microbiological profile of septic arthritis in adults: Lessons learnt and treatment strategies

Objective

The aim of this study is to characterise the clinical and microbiological profile of adult patients treated at our orthopaedic unit with septic arthritic between 2006 and 2017.

Materials and Methods

A total of 70 patients who were admitted with a diagnosis of septic arthritis between 2006 and 2017 were included in the study. The patients' clinical and epidemiological characteristics were surveyed; microbiological profile and the complications relating to the patients' treatment were identified.

Results

Septic arthritis was more common among males (83%). About 75% of the patients presented with a history of fever. The knee was the most commonly affected joint (71%), followed by the hip. While C-reactive protein was found to be consistently >75, total blood white blood cell (WBC) counts were found not to be reflective of the presence of infection with a mean WBC count of only 13,561/cu.mm, and Gram stain examination had a poor sensitivity of 47%. Among the co-morbidities, the most prevalent association was with diabetes mellitus. The infectious agent most frequently isolated was Staphylococcus aureus(42.85%). The antibiotic sensitivity pattern has evolved since the early years, with resistant strains becoming increasingly prevalent. Unusually, high incidence of streptococci was noted (30%), contrary to the published literature. One-third of the patients had multi-resistant organisms. Septic arthritis left 70% of the patients with a significant residual disability at 6 months follow-up and had 4.25% mortality.

Conclusion

Changing sensitivity patterns of microbes in septic arthritis point to a need for reconsidering empirical antibiotic therapy. Joint damage following infection can lead to significant disability.

Native joint septic arthritis with Veillonella species

Septic arthritis usually presents as subacute monoarticular inflammation. Majority of the cases in healthy adults are caused by methicillin-resistant Staphylococcus aureus, streptococci and certain gram-negative organisms, mostly in the setting of extremes of ages, trauma or immunosuppression. This is a case of a healthy adult with a sudden onset of inflammation of the knee joint, being diagnosed with septic arthritis of the left knee with Veillonella sp. growing from the joint aspirate on two successive cultures. The patient was treated with 6 weeks of oral metronidazole and 4 weeks of intravenous ceftriaxone in addition to arthroscopic drainage and irrigation. Rare causes of septic arthritis should be considered even in healthy adults with native joints. Closer follow-up might be needed to ensure successful treatment.

Evaluation and Management of Septic Arthritis and its Mimics in the Emergency Department

Septic arthritis is a dangerous medical condition associated with significant morbidity and mortality. However, the differential diagnosis can be broad with conditions that mimic this disease and require different evaluation and treatment. This narrative review presents the emergency medicine evaluation and management, as well as important medical conditions that may mimic this disease. Septic arthritis commonly presents with monoarticular joint pain with erythema, warmth, swelling, and pain on palpation and movement. Fever is present in many patients, though most are low grade. Blood testing and imaging may assist with the diagnosis, but the gold standard is joint aspiration. Management includes intravenous antibiotics and orthopedic surgery consult for operative management vs. serial aspirations. Clinicians should consider mimics, such as abscess, avascular necrosis, cellulitis, crystal-induced arthropathies, Lyme disease, malignancy, osteomyelitis, reactive arthritis, rheumatoid arthritis, and transient synovitis. While monoarticular arthritis can be due to septic arthritis, other medical and surgical conditions present similarly and require different management. It is essential for the emergency clinician to be aware how to diagnose and treat these mimics.

Bacteriological profile of community-acquired musculoskeletal infections: a study from Queensland

BACKGROUND

The purpose of this study was to determine bacteriology of community-acquired musculoskeletal infections requiring hospitalization and to compare this with published national and international data. This will help treating physicians select the appropriate antibiotic.

METHODS

All patients who underwent surgical procedures for community-acquired musculoskeletal infections over a period of 22 months were included in the study. Hospital acquired infections, post-operative infections and infections involving prosthetic joints were excluded. Patient characteristics, treatment details, cultured organisms and their antibiotic sensitivity were recorded.

RESULTS

Forty-five patients with 46 cases met the inclusion criteria. Ten patients were from paediatric age group. Soft tissue infections were the most common diagnosis and accounted for 20 cases. The remainder were septic arthritis (n = 17) and osteomyelitis (n = 9). Thirteen patients (28.3%) had negative cultures from the operative samples. Staphylococcus aureus was the most common isolated organism overall accounting for 23 cases (69.7%). Methicillin-resistant S. aureus (MRSA) sensitive to vancomycin was cultured in four adult cases (12.1%), of which three were hand infections (50%). For the entire cohort, 67.7% and 61.3% isolates that were tested were sensitive to cefazolin and flucloxacillin, respectively.

CONCLUSION

The bacteriological profile in this study is consistent with European and Australian data. While the overall MRSA infection rate was low, it was much higher among hand infections and is comparable to reports from the USA. Flucloxacillin and cefazolin should be considered as the first line of antibiotic therapy for all cases. Vancomycin should be considered when MRSA is suspected.

Acute septic arthritis of shoulder joint caused by Aeromonas veronii biotype sobria

We present the case of a 91-year-old woman who presented with a 2‑day history of progressive pain and immobility of the right shoulder joint after fever of unknown etiology. Aeromonas sobria was isolated from a culture of purulent synovial fluid. The clinical condition gradually improved with the application of appropriate antibiotics and no surgical intervention was necessary. This report indicates that acute septic arthritis may result from Aeromonas veronii biotype sobria infections in healthy people. This case is contrary to the previous reports due to the absence of obvious risk factors.

Septic Arthritis and Prosthetic Joint Infections in Older Adults

Older adults are at increased risk for septic arthritis and prosthetic joint infections (PJI), owing at least in part to comorbid conditions and frailty. An increasing number of older adults undergo total joint arthroplasty to improve their quality of life. Infections in older adults differ from younger populations by the causative organisms, a great proportion of which are Staphylococcal infections. Targeting important modifiable and nonmodifiable risk factors may prevent or reduce the burden of joint infections in older adults. This review summarizes the epidemiology, pathogenesis, clinical manifestations, diagnosis, management, and prevention of septic arthritis and PJI in older adults.

Septic Arthritis of Native Joints

Septic arthritis is a rheumatologic emergency that may lead to disability or death. Prompt evacuation of the joint, either by arthrocentesis at the bedside, open or arthroscopic drainage in the operating room, or imaging-guided drainage in the radiology suite, is mandatory. Methicillin-resistant Staphylococcus aureus (MRSA) has become a major cause of septic arthritis in the United States. MRSA joint infection seems to be associated with worse outcomes. Antibiotic courses of 3 to 4 weeks in duration are usually adequate for uncomplicated bacterial arthritis. Treatment duration should be extended to 6 weeks if there is imaging evidence of accompanying osteomyelitis.

Clinical findings of bacteremic septic arthritis according to the site of acquisition: The overlap between health care-related and community- and nosocomial-acquired cases

BACKGROUND

The site of acquisition of infection may have a major impact on outcome. The health care-related (HCR) environment has recently come under scrutiny. In a group of patients with bacteremic septic arthritis (SA), we compared their characteristics, type of SA, microbiology and prognosis according to the site of acquisition: community-acquired (CA), nosocomial-acquired (NA), and HCR.

METHODS

We studied all patients with bacteremic SA seen at our institution between 1985 and 2013. Data were obtained from a protocol of prospectively recorded bacteremia cases.

RESULTS

There were 273 cases of bacteremic SA (CA: 51%; NA: 31%; and HCR: 18%). NA and HCR sites were more frequent in older and fragile patients. SA of peripheral joints was the most common presentation; infections of the axial skeleton predominated in CA and HCR (24%), and prosthetic joint infection in NA (44%). MRSA and Pseudomonas aeruginosa were mainly found in NA (21% and 6% respectively) and HCR (14% and 8% respectively), whereas Streptococcus spp. was more frequent in CA (30%) and HCR (28%). The 30-day mortality rates were: CA 7%, HCR 18%, and NA 26%.

CONCLUSION

The characteristics of HCR-SA overlapped with those of the CA or NA-SA cases. The HCR and NA cases presented more advanced age, greater fragility, and the predominance of difficult-to-treat microorganisms, while the HCR and CA cases presented an involvement of the axial skeleton, streptococcal etiology, and a lower number of prosthetic joint infections. Our data show that the site of acquisition should be considered when planning diagnostic and therapeutic management for SA.

Clinical manifestations and bacteriological features of culture-proven Gram-negative bacterial arthritis

BACKGROUND/PURPOSE

To investigate the clinical manifestations and bacteriological features of culture-proven, Gram-negative bacterial arthritis.

METHODS

This study was conducted at the Chi Mei Medical Center, a 1300-bed teaching hospital located in southern Taiwan. Patients with synovial fluid cultures positive for Gram-negative bacilli (GNB) during the period January 2009 to May 2014 were identified from the hospital's computerized microbiology database.

RESULTS

During the study period, a total of 48 patients with culture-confirmed, GNB septic arthritis were identified. In the majority of patients (n = 33, 68.8%), the knee was the most commonly involved joint. The most common causative pathogen was Pseudomonas spp. (n = 16, 33.3%), followed by Escherichia coli (n = 13, 28.1%). Among the 29 clinical isolates of Enterobacteriaceae, eight (27.6%) were resistant to ceftriaxone and six (20.7%) were resistant to cefpirome. Three E. coli isolates and three Klebsiella pneumoniae isolates were extended-spectrum beta-lactamase producers (n = 6, 20.7%). Among the nonfermenting GNB (NFGNB), 21.1% were resistant to ceftazidime, 21.1% were resistant to ciprofloxacin, 26.3% were resistant to piperacillin-tazobactam, and 15.8% were resistant to imipenem. The overall mortality rate was 10.4%, and the significant risk factors for death were concomitant bacteremia [odds ratio (OR): 14.6, 95% confidence interval (CI): 1.9-115.2, p = 0.011] and liver cirrhosis (OR: 20.0, 95% CI: 2.4-169.9, p = 0.006).

CONCLUSION

Approximately 25% of cases of septic arthritis were due to GNB and resistance to commonly used antimicrobial agents was common. Liver cirrhosis and concomitant bacteremia were significant risk factors for death.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

Septic arthritis due to methylcyllin-resistant Staphylococcus aureus in adults

INTRODUCTION

Septic arthritis due to methylcyllin resistant Staphylococcus aureus (MRSA) is a serious infection that has increased in incidence in the past 10years.

METHODS

We conducted a retrospective study (1984-2011) in which a description of the clinical and epidemiological characteristics of MRSA arthritis in adults was performed and then compared to native joint infections caused by MRSA vs. methylcyllin sensitive Staphylococcus aureus (MSSA).

RESULTS

Fourteen MRSA infections were included (7 native joint, 5 prosthetic and 2 bursae). No case was polyarticular. There was significant comorbidity, although none was associated to rheumatoid arthritis. Seven patients had bacteremia. Four required surgical treatment. Six died. When comparing the 7 patients with native joint MRSA infection with the 17 cases caused by MSSA, no significant differences in risk factors were seen, except more malignancies in the MRSA group. The infection was polyarticular in 7 cases (41%) of the MSSA group. Bacteremia was more frequent in the MRSA group (71.4 vs 58.8%). Empirical antibiotic was useful in 28.6% of MRSA cases versus 100% of MSSA cases. There was a greater tendency to associated mortality in MRSA arthritis (57.1% vs 17.6%, P=.07).

CONCLUSIONS

MRSA septic arthritis is a serious condition that occurs in the elderly and patients with high comorbidity. It is usually monoarticular, with positive blood cultures and higher mortality than MSSA arthritis. In patients at risk, vancomycin empiric antibiotic therapy is indicated.

The inhibition of fluorescence resonance energy transfer between multicolor quantum dots for rapid and sensitive detection of Staphylococcus aureus

In this paper, we constructed the fluorescence resonance energy transfer (FRET) system between two multi-color quantum dots (QDs) of two sizes for rapid and sensitive detection of Staphylococcus aureus. In this system, green-emitting QDs conjugated with rabbit anti-S. aureus antibodies were used as energy donors while orange-emitting QDs conjugated with goat-anti-rabbit IgG were used as energy acceptors to form FRET system. Pre-binding of Staphylococcus aureus (S. aureus) on the donor occupied the binding sites and thus blocked resonance energy transfer between two colors QDs, leading to the quenching fluorescence of the acceptor. The fluorescence of acceptor has a linear calibration graph with the concentrations of S. aureus from 52 to 2.6×10(5) CFU mL(-1). The low detection limit was 10 CFU/mL. It was worth mentioning that the detection method of S. aureus had been applied to the analysis of apple juice and milk samples, which could potentially be developed into a sensor in the further study.

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.

Clinical and epidemiological differences between septic arthritis of the knee and hip caused by oxacillin-sensitive and -resistant s. aureus

OBJECTIVE

To establish the risk factors for joint infection by oxacillin-resistant Staphylococcus aureus (MRSA) using clinical and epidemiological data.

METHODS

All septic arthritis cases of the knee and hip diagnosed and treated in our institution from 2006 to 2012 were evaluated retrospectively. Only patients with cultures identified as microbial agents were included in the study. The clinical and epidemiological characteristics of the patients were analyzed, seeking the differences between populations affected by MRSA and oxacillin-sensitive Staphylococcus aureus (MSSA).

RESULTS

S. aureus was isolated in thirty-five patients (46.0%) in our total sample, 25 in the knee and 10 in the hip. Of these 35 patients, 22 presented with MSSA and 13 presented with MRSA. Provenance from a health service-related environment, as described by the Centers for Disease Control and Prevention, was the only variable associated with oxacillin-resistant strains of this bacterium (p = 0.001).

CONCLUSION

Provenance from a health service-related environment was associated with a higher incidence of MRSA-related septic arthritis, suggesting that this agent should be considered in the initial choice of antibiotic treatment. Previous surgeries of the knee or affected limb and the absence of leukocytes might also be related to infection with this agent.

Septic arthritis in intravenous drug abusers: a historical comparison of habits and pathogens

BACKGROUND

Intravenous drug abuse (IVDA) is a common problem; there were more than 16 million users worldwide in 2008. Numerous reports highlight the infectious skeletal complication associated with IVDA.

OBJECTIVE

To determine septic arthritis pathogens in IVDA in a U.S. hospital and compare the current causative organisms to a cohort from the 1980s at the same institution.

METHODS

An institutional review board-approved retrospective cohort study compared a consecutive series of IVDA septic arthritis patients over a 10-year period, 1999-2008 (Group B), with an IVDA septic arthritis database that was collected in the 1980s (Group A). Endpoints were: bacterial species and staph species antibiotic susceptibility.

RESULTS

Group B included 58 patients (35 men, 23 women) with a median age of 46.5 years. Group A included 38 patients (30 men, 8 women), with a median age of 32.5 years. The sets were significantly different in pathogens (p = 0.0443). The most common organisms were Staphylococcus (staph) species (B 74.51%, A 52.63%), followed by Streptococcus (strep) species (B 7.84%, A 31.58%), Pseudomonas (B 13.73%, A 13.16%), and Serratia (B 3.92%, A 2.63%). Of the total number of septic joints, methicillin-resistant Staphylococcus aureus (MRSA) made up 39% of Group B and 34% of Group A. However, within the staph species, MRSA made up 53% of Group B and 65% of Group A. Strep species made up 7.84% (Group B) vs. 31.58% (Group A), and Pseudomonas (13%) and Serratia (3-4%) were similar. In the Group B cohort, methicillin-susceptible Staphylococcus aureus (MSSA) had a predilection to infect the knee (94.4%), whereas MRSA was found more often in the hip (57.1%).

CONCLUSIONS

In IVDAs, MRSA is the most common pathogen causing septic arthritis. The ratio of staph species in septic joints is increasing, and the ratio of MRSA to MSSA remains high (>50%). Strep species are much less common.

Septic arthritis: patients with or without isolated infectious agents have similar characteristics

PURPOSE

Septic arthritis can be disabling and life-threatening, requiring prompt diagnosis and treatment. The infectious agent is not always identified in these patients. We revaluate septic arthritis cases discharged from our department, describing the affected population, causative microorganisms and antibiotic therapy used, and characterised differences between patients with and without isolated pathogenic agents.

METHODS

Sixty-eight septic arthritis patients were included in this study. Diagnosis was based on clinical findings, and/or the presence of joint purulent material, and/or bacterial pathogen isolation from joint fluid/synovial membrane/blood cultures and response to antibiotics. Data analysis was performed using SPSS 20.

RESULTS

Patients had a mean age of 61.1 ± 18.8 years, without sex predominance. 26.5 % had an infection ≤ 15 days before septic arthritis diagnosis. Besides previous infection, 57.4 % had ≥ 1 risk factors for septic arthritis, most commonly pharmacological immunosuppression (20.6 %), diabetes mellitus type 2 (19.1 %) and rheumatoid arthritis (17.6 %). The knee was the most often affected (54.3 %). Only 39.7 % presented fever from clinical onset until hospital admission (mean 13.4 ± 18.9 days). Leucocytosis was present in 45.6 % of patients, elevated erythrocyte sedimentation rate (ESR) in 75 % and elevated C-reactive protein (CRP) in 97.1 %. 5.9 % had articular damage attributable to septic arthritis. An infectious agent was isolated in 41.2 % of patients, with Staphylococcus aureus being the most frequent. 38.7 % of synovial fluid and 23.5 % of synovial membrane cultures were positive. Patients with an identified infectious agent have no significant differences other than more days of hospitalisation (p = 0.003) and in-hospital antibiotic treatment (p = 0.017).

CONCLUSION

Synovial fluid and synovial membrane cultures more often identified pathogens compared to blood or urine cultures. Patients with and without an identified infectious agent have similar demographic, clinical, laboratory and radiographic characteristics.

Rapid detection of Staphylococcus aureus and methicillin resistance in bone and joint infection samples: evaluation of the GeneXpert MRSA/SA SSTI assay

The GeneXpert MRSA/SA SSTI assay was compared to conventional cultures to detect Staphylococcus aureus and methicillin-resistance from 91 bone and joint infection samples. Sensitivity and specificity were 94.4% and 100%. Three false-positive results were observed, in fact providing from patients known to be infected by S. aureus on the basis of other concomitant osteoarticular samples, which suggests that PCR was more sensitive than culture. This diagnosis accuracy may help shorten toxic and non-optimal empirical therapies such as glycopeptides in case of methicillin-susceptible strains.

Epidemiology of septic arthritis of the knee at Hospital das Clínicas, Universidade de São Paulo

Background

Septic arthritis is an infrequent disease although very important due to the possibility of disastrous outcomes if treatment is not adequately established. Adequate information concerning the epidemiology of septic arthritis is still lacking due to the uncommon nature of the disease as well as the struggle to establish a correct case-definition.

Objective

To epidemiologically characterize the population seen at Hospital das Clínicas, University of São Paulo with a diagnosis of septic arthritis between 2006 and 2011.

Methods

Sixty-one patients diagnosed with septic arthritis of the knee between 2006 and 2011 were retrospectively evaluated. The patients’ clinical and epidemiological characteristics, the microorganisms that caused the infection and the patients’ treatment and evolution were analyzed.

Results

Septic arthritis of the knee was more common among men, with distribution across a variety of age ranges. Most diagnoses were made through positive synovial fluid cultures. The most prevalent clinical comorbidities were systemic arterial hypertension and diabetes mellitus, and the most commonly reported joint disease was osteoarthritis. Staphylococcus aureus was the prevailing pathogen. Fever was present in 36% of the cases. All patients presented elevation in inflammatory tests. Gram staining was positive in only 50.8% of the synovial fluid samples analyzed. Six patients presented complications and unfavorable evolution of their condition.

Conclusion

S. aureus is still the most common pathogen in acute knee infections in our environment. Gram staining, absence of fever and normal leukocyte count cannot be used to rule out septic arthritis.

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.

Critical orthopedic skills and procedures

Musculoskeletal injury and diseases are common presentations in the Emergency Department. Emergency physicians must be versed in the critical procedural skills necessary to diagnose joint infection, manage fractures and dislocations, and assess for compartment syndrome. Arthrocentesis, splinting, dislocation reduction, and the evaluation of limb compartment syndrome are reviewed.

Subtalar joint septic arthritis in a patient with hypogammaglobulinemia

The clinical presentation of a monoarticular, red, hot, and swollen joint has many possible diagnoses, including septic arthritis, which is 1 of the most devastating. The morbidity associated with this pathologic process involves permanent joint damage and the potential for progression to systemic illness and, even, mortality. The common risk factors for joint sepsis include a history of rheumatoid arthritis, previous joint surgery, joint prosthesis, intravenous drug abuse, alcoholism, diabetes, previous intra-articular steroid use, and cutaneous ulceration. The diagnosis is primarily determined from the culture results after arthrocentesis and correlation with direct visualization, imaging, and various serologies, including synovial analysis. In the present report, a case of an insidious presentation of subtalar joint septic arthritis and its association with a unique patient presentation concomitant with primary immunodeficiency and culture-proven Myocplasma hominis infection is discussed. Septic arthritis has a predilection for the lower extremities and typically is isolated to the hip or knee, with less common involvement of the ankle or metatarsophalangeal joints. Owing to the uncommon nature of primary immunodeficiency disorders and the paucity of studies discussing their association with septic arthridites, we aimed to raise awareness of subtalar joint septic arthritis and to provide a brief overview of the pathogenesis as it presented in a 33-year-old male with X-linked hypogammaglobulinemia/agammaglobulinema.

What's New in the Management of Bacterial Septic Arthritis?

Septic arthritis is a common rheumatological emergency requiring prompt diagnosis and treatment, since delays in management can lead to high morbidity and mortality. In this review article, we discuss the epidemiology and recent advances in knowledge of the pathogenesis of septic arthritis, with a special emphasis on various bacterial and host factors involved in mediating the inflammatory process and the potential for targeted therapy to modulate the immune response. Recent advances in laboratory and imaging techniques are reviewed along with treatment and potential new therapies.

Direct detection of Staphylococcus osteoarticular infections by use of Xpert MRSA/SA SSTI real-time PCR

We evaluated the Xpert MRSA/SA SSTI real-time PCR assay (Cepheid, Sunnyvale, CA) directly on perioperative bone and joint samples. The sensitivity and specificity for detection of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-resistant coagulase-negative Staphylococcus were, respectively, 100% and 98.3%, 100% and 100%, and 100% and 95.3%. The median total test turnaround time was 72 min for PCR versus 79 h for culture. Using these rapid results, appropriate antibiotic treatment could be rapidly initiated.

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.

What are we doing about septic arthritis? A survey of UK-based rheumatologists and orthopedic surgeons

This study aims to determine the current practices and beliefs of United Kingdom (UK)-based rheumatologists and orthopedic surgeons (OS) in managing septic arthritis (SA) and to determine awareness levels of national guidance. Two-hundred OS and 200 rheumatologists were sent a link to a web-based survey tool via email. Questions posed related to the management of SA, including the respondent's views on antibiotic therapy, joint drainage, which specialty should manage these cases, and also the clinician's evidence base. There were 354 functioning addresses with 182 responses (51%). One hundred fifty-one (77 OS, 74 rheumatologists) (43%) responses were complete and included for analysis. Eighty percent of rheumatologists and 82% of OS recommended 6-weeks total antibiotic therapy. Seventy-three percent in each group recommended 1-2 weeks intravenous therapy initially followed by oral continuation therapy. In patients at risk of methicillin-resistant Staphylococcus aureus (MRSA), 25% rheumatologists and 14% OS would ensure MRSA cover. Seventy-seven percent of rheumatologists and 66% of OS recommended surgical joint drainage; 22% and 27%, respectively, recommended repeated closed needle aspiration as their chosen method of joint drainage. Sixty-six percent of rheumatologists and 65% of OS believed OS should manage SA. Twenty-three percent of rheumatologists and 22% of OS quoted published guidance as their main evidence base in the treatment of SA. Only 24% of rheumatologists and 34% of OS quoted British Society of Rheumatology (BSR) guidance when asked if they were aware of any guidelines. Views of rheumatologists and OS are not that dissimilar in managing SA. Surprisingly, rheumatologists are more aggressive regarding the recommendation for surgical joint drainage. Within both groups, significant variation in management principles exists often discrepant to recommendations laid out by the BSR. There are poor awareness levels of the BSR guidelines.

Emergent evaluation of injuries to the shoulder, clavicle, and humerus

This article provides a review of the evaluation and treatment of common injuries to the shoulder, humerus, and clavicle in the emergency department (ED) setting. In addition to a focused review of the shoulder's physical examination, topics include common emergent injuries such as glenohumeral dislocations, proximal humerus fractures, and acromioclavicular separations as well as less common, but important injuries including pectoralis and biceps tendon injuries and sternoclavicular dislocations. Accurate recognition and management of these injuries is essential in the optimal care of patients in the ED.