Epidemiology, Management, and Outcomes of Large and Small Native Joint Septic Arthritis in Adults.

BACKGROUND: Native joint septic arthritis (NJSA) is poorly studied. We describe the epidemiology, treatment, and outcomes of large joint NJSA (LNJSA) and small joint NJSA (SNJSA) in adults at Middlemore Hospital, Auckland, New Zealand. METHODS: This was a coding-based retrospective study of patients ≥16 years old admitted between 2009 and 2014. Prosthetic joint infections were excluded. RESULTS: Five hundred forty-three NJSA episodes were included (302 LNJSA, 250 SNJSA). Only 40% had positive synovial fluid culture. Compared to SNJSA, LNJSA has higher incidence (13 vs 8/100 000 person-years [PY]), occurs in older, more comorbid patients, and is associated with greater rates of treatment failure (23% vs 12%) and mortality, despite longer antibiotic treatment. Total incidence is higher than previously reported (21/100 000 PY), with marked interethnic variation. Incidence rises with age (LNJSA only) and socioeconomic deprivation (LNJSA and SNJSA). Tobacco smokers and males are overrepresented. The most commonly involved joints were knee (21%) and hand interphalangeal (20%). Staphylococcus aureus was the most common pathogen (53%). Mean antibiotic duration was 25 days for SNJSA and 40 days for LNJSA, and the mean number of surgical procedures was 1.5 and 1.6, respectively. Treatment failure was independently associated with LNJSA, age, intra-articular nonarthroplasty prosthesis, and number of surgical procedures. CONCLUSIONS: This is the largest contemporary series of adult NJSA. SNJSA has better outcomes than LNJSA and may be able to be safely treated with shorter antimicrobial courses. Incidence is high, with significant ethnic and socioeconomic variation. Microbiological NJSA case ascertainment underestimates case numbers as it frequently excludes SNJSA.

Antibiotic resistance in early periprosthetic joint infection.

BACKGROUND: Prophylactic antibiotics significantly reduce prosthetic joint infection (PJI) rates after hip and knee arthroplasty. However, rising antibiotic resistance has raised concerns over the adequacy of conventional prophylaxis. This study aimed to identify organisms causing PJIs in hip and knee arthroplasty secondary to perioperative contamination and their susceptibility to current prophylactic antibiotics. METHODS: We performed a retrospective audit of 4009 primary hip and knee arthroplasties (1852 hips and 2157 knees) at three tertiary referral hospitals. PJIs were identified according to the Infectious Diseases Society of America definition, and patients were followed-up for 2 years. For patients with confirmed PJIs, causative bacteria and their antibiotic susceptibilities were identified. RESULTS: Thirty-five PJI cases were identified (13 hips and 22 knees). The overall definite PJI rate was 0.87% (0.7% for hips, 1.0% for knees). Ninety-six percent of patients with PJI received cefazolin prophylaxis. Culture information was available for 30 cases. The most common infecting organisms were coagulase-negative staphylococci (CoNS), causing 35% of infections. Ninety-two percent of CoNS strains were cefazolin-resistant. Twenty-five percent of patients were infected with Staphylococcus aureus, 9.1% of which were methicillin-resistant. Overall, 53% of infecting organisms were cefazolin-resistant. CONCLUSIONS: The majority of bacteria causing early PJI are resistant to cefazolin. Whilst many organisms cultured were susceptible to vancomycin, there is currently insufficient evidence to justify its routine use as a prophylactic. However, when treating PJI in the early postoperative period, surgeons should be aware that most organisms will be methicillin-resistant, and the choice of empirical antibiotic treatment should reflect this.

HIV-associated tuberculosis in Auckland.

AIM: New Zealand has low rates of disease caused by to Mycobacterium tuberculosis (TB) and Human Immunodeficiency Virus (HIV). This study is the first to describe a New Zealand cohort of patients with HIV-associated TB. METHOD: We retrospectively reviewed the clinical records, laboratory data and chest radiographs of all patients who were diagnosed with HIV-associated TB and who commenced treatment for TB disease at Auckland City Hospital between January 1997 and July 2009. RESULTS: During the 12-and-a-half year study period, 40 patients were diagnosed with HIV-associated TB. The median age was 37 years and the median CD4 count was 130 cells/mm3. Only 2 patients were New Zealand born. Twenty-four (60%) patients had known HIV infection prior to their diagnosis of TB disease. Two patients with known HIV infection and positive tuberculin skin tests had not received treatment for latent tuberculosis infection (LTBI). Twenty-three (58%) patients received antiretroviral treatment during their TB treatment. There were 21 episodes of treatment interruption or immune reconstitution inflammatory syndrome. Three (8%) patients died. CONCLUSIONS: New Zealand continues to have a low incidence of HIV-associated TB. Early HIV diagnosis with universal screening and the treatment of LTBI in persons living with HIV infection is key to minimising the disease burden.

Emphysematous osteomyelitis: a case report and review of the literature.

We report the case of a 15-year-old girl with pelvic and sacral emphysematous osteomyelitis caused by Fusobacterium necrophorum. This infection was cured following four surgical procedures and 4 weeks of intravenous then 4 weeks of oral antibiotics. We review our case alongside the 24 previously reported cases of emphysematous osteomyelitis in the literature. The 25 cases include 15 monomicrobial and 10 polymicrobial infections. The causative organism(s) in all but three cases included an anaerobe or a member of the Enterobacteriaceae family. A significant underlying comorbidity was reported in 18 cases. At least 15 cases required one or more surgical procedures. There was a significant associated mortality with eight (32%) patients dying in hospital at 7 to 56 days after the diagnosis of emphysematous osteomyelitis.