Adult Native Joint Septic Arthritis: A Nine-Year Retrospective Analysis in a Portuguese University Hospital

Abstract

Introduction: Septic arthritis of a native joint represents a medical emergency. Drainage and effective antibiotic treatment are critical to avoid joint destruction and long-term impairment. The aim of this study was to evaluate epidemiological and clinical characteristics of patients with the diagnosis of septic arthritis to help establish local guidelines for empirical antibiotic treatment.Material and Methods: Retrospective analysis of adult patients admitted at Centro Hospitalar Universitário do Porto from 2009 to 2017 with suspected native joint septic arthritis. Relevant demographics, microbiology findings and respective antibiotic susceptibilities were analysed.Results: Ninety-seven patients, predominantly males (59.8%) with a median age of 61 years old were included. The most commonly reported comorbidity associated with septic arthritis was diabetes mellitus (20.6%). The knee was the most commonly affected joint (71.1%). Arthrocentesis was performed in all patients, but only 50.5% had positive microbial growth in the synovial fluid. Staphylococcus aureus was the most frequently identified microorganism, 86% of which were methicillin susceptible. Gram-negative bacteria were the causative agent in 15% of cases. A wide range of empirical antibiotic regimens were prescribed with a combination of vancomycin/carbapenem being the most common (30.9%). Analysis of antibiotic susceptibility profiles revealed that amoxicillin/clavulanate would have been appropriate as the initial regimen in 89% of cases.Discussion: The main causative pathogen was Staphylococcus aureus, with methicillin resistant Staphylococcus aureus remaining rare. The proportion of Gram-negative bacteria implies that these agents should be covered by empirical treatment, although no case of Pseudomonas infection has been identified. Therefore, antipseudomonal coverage is not necessary in empirical regimens.Conclusion: Routine coverage of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa is not warranted but must be considered when specific risk factors are found. Amoxicillin/clavulanate can provide adequate antibiotic coverage as an empirical treatment for adult native joint septic arthritis. Its use may allow a reduction in use of broader spectrum antibiotics.

Atypical Staphylococcal Septic Arthritis in a Native Hip: A Case Report and Review

“…S. aureus remains a challenging pathogen to diagnose in septic arthritis, with modern methods failing to reach the performance necessary to identify it in time to reduce morbidity and mortality. Patients with risk factors such as diabetes and tobacco usage are at increased risk of infection and severity [ 15 , 17 , 18 ]. In addition to diagnostic method improvements, preventative research is also needed to mitigate morbidity associated with patients like ours.…”

“…Balato et al found that culture negative infections have been reported to range from 16.7% to 78.4% [ 14 ]. A nine-year retrospective analysis at a single center in Portugal by Cipriano et al, with predominantly S. aureus septic arthritis, noted that only 50.5% of arthrocentesis cultures had positive growth in synovial fluid [ 15 ]. Another retrospective study by Daynes et al analyzing 183 cases of native joint infections found that joint fluid cultures were positive in 55% of cases; and of these cases, blood cultures yielding the same pathogen were found in 54% [ 16 ].…”

“…Known risk factors for septic arthritis include: diabetes mellitus, HIV and immunosuppression, intravenous drug use, prosthetic joints, age older than 80, smoking, rheumatoid arthritis and osteoarthritis, sexual activity, recent surgery, skin infection, and iatrogenic causes [ 7 ]. Cipriano et al also noted diabetes as the most commonly reported comorbidity with 20.6% of patients having diabetes [ 15 ]. A five-year single-center retrospective study in New Zealand of native joint septic arthritis by McBride et al found that 35% of patients used tobacco and 24% of patients had diabetes mellitus [ 17 ].…”

Clinical Characteristics and In-Hospital Outcomes in Dialysis Patients with Septic Arthritis

“…The causative organisms in this study were predominantly Gram-positive bacteria, with S. aureus and Streptococci attributable for more than 80% of these cases. MRSA was accountable for septic arthritis in more than half of the patients with bacteremia (58.3%) and in almost half of the patients who had positive synovial fluid cultures (47.6%)—both of these prevalence rates were higher than that of the general population [ 4 , 28 , 29 ]. The incidence rate of MRSA infection in dialysis patients in this study is noticeably higher than the rates reported in septic arthritis studies with or without dialysis status [ 9 , 29 , 30 ].…”

“…MRSA was accountable for septic arthritis in more than half of the patients with bacteremia (58.3%) and in almost half of the patients who had positive synovial fluid cultures (47.6%)—both of these prevalence rates were higher than that of the general population [ 4 , 28 , 29 ]. The incidence rate of MRSA infection in dialysis patients in this study is noticeably higher than the rates reported in septic arthritis studies with or without dialysis status [ 9 , 29 , 30 ]. A higher risk of MRSA bacteremia in dialysis patients along with increased incidence of MRSA infections in both healthcare and community settings may explain this difference [ 31 , 32 , 33 ].…”