The Not-So-Good Prognosis of Streptococcal Periprosthetic Joint Infection Managed by Implant Retention: The Results of a Large Multicenter Study

BACKGROUND.

Streptococci are not an infrequent cause of periprosthetic joint infection (PJI). Management by debridement, antibiotics, and implant retention (DAIR) is thought to produce a good prognosis, but little is known about the real likelihood of success.

METHODS.

A retrospective, observational, multicenter, international study was performed during 2003-2012. Eligible patients had a streptococcal PJI that was managed with DAIR. The primary endpoint was failure, defined as death related to infection, relapse/persistence of infection, or the need for salvage therapy.

RESULTS.

Overall, 462 cases were included (median age 72 years, 50% men). The most frequent species was Streptococcus agalactiae (34%), and 52% of all cases were hematogenous. Antibiotic treatment was primarily using β-lactams, and 37% of patients received rifampin. Outcomes were evaluable in 444 patients: failure occurred in 187 (42.1%; 95% confidence interval, 37.5%-46.7%) after a median of 62 days from debridement; patients without failure were followed up for a median of 802 days. Independent predictors (hazard ratios) of failure were rheumatoid arthritis (2.36), late post-surgical infection (2.20), and bacteremia (1.69). Independent predictors of success were exchange of removable components (0.60), early use of rifampin (0.98 per day of treatment within the first 30 days), and long treatments (≥21 days) with β-lactams, either as monotherapy (0.48) or in combination with rifampin (0.34).

CONCLUSIONS.

This is the largest series to our knowledge of streptococcal PJI managed by DAIR, showing a worse prognosis than previously reported. The beneficial effects of exchanging the removable components and of β-lactams are confirmed and maybe also a potential benefit from adding rifampin.

Acute scrotal ulcers in typhoid Fever: case report and literature review

Background. In developed countries, typhoid fever is a travel-associated disease that is often overlooked. However, as standard blood and stool culture methods have relatively low sensitivity, diagnosis depends heavily on clinical signs and symptoms and on a high level of suspicion.

Methods. Reported here is the case of an 18-year-old male who presented with fever and acute scrotal ulcers and whose blood cultures were positive for Salmonella enterica serotype Typhi. A review of genital ulcers associated with typhoid fever in the literature is discussed.

Conclusion. This report suggests that typhoid fever is a differential diagnosis of acute genital ulcers.

Oral versus parenteral antimicrobials for the treatment of cellulitis: a randomized non-inferiority trial

OBJECTIVES

To determine whether outcomes for patients with cellulitis treated with oral antimicrobials are as good as for those who are treated with parenteral antimicrobials.

METHODS

A prospective randomized non-inferiority trial was conducted at a tertiary teaching hospital in Melbourne, Australia. Participants were patients referred by the emergency department for treatment of uncomplicated cellulitis with parenteral antimicrobials. Patients were randomized to receive either oral cefalexin or parenteral cefazolin. Parenteral antimicrobials were changed to oral after the area of cellulitis ceased progressing. The primary outcome was days until no advancement of the area of cellulitis. A non-inferiority margin of 15% was set for the oral arm compared with the parenteral arm. Secondary outcomes were failure of treatment, pain, complications and satisfaction with care. This trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12611000685910).

RESULTS

Twenty-four patients were randomized to oral antimicrobials and 23 to parenteral antimicrobials. Mean days to no advancement of cellulitis was 1.29 (SD 0.62) for the oral arm and 1.78 (SD 1.13) for the parenteral arm, with a mean difference of -0.49 (95% CI: -1.02 to +0.04). The upper limit of the 95% CI of the difference in means of +0.04 was below the 15% non-inferiority margin of +0.27 days, indicating non-inferiority. More patients failed treatment in the parenteral arm (5 of 23, 22%) compared with the oral arm (1 of 24, 4%), although this difference was not statistically significant (P=0.10). Pain, complications and satisfaction with care were similar for both groups.

CONCLUSIONS

Oral antimicrobials are as effective as parenteral antimicrobials for the treatment of uncomplicated cellulitis.

Murray Valley encephalitis: a review of clinical features, diagnosis and treatment

Murray Valley encephalitis virus (MVEV) is a mosquito-borne virus that is found across Australia, Papua New Guinea and Irian Jaya. MVEV is endemic to northern Australia and causes occasional outbreaks across south-eastern Australia. 2011 saw a dramatic increase in MVEV activity in endemic regions and the re-emergence of MVEV in south-eastern Australia. This followed significant regional flooding and increased numbers of the main mosquito vector, Culex annulirostris, and was evident from the widespread seroconversion of sentinel chickens, fatalities among horses and several cases in humans, resulting in at least three deaths. The last major outbreak in Australia was in 1974, during which 58 cases were identified and the mortality rate was about 20%. With the potential for a further outbreak of MVEV in the 2011-2012 summer and following autumn, we highlight the importance of this disease, its clinical characteristics and radiological and laboratory features. We present a suspected but unproven case of MVEV infection to illustrate some of the challenges in clinical management. It remains difficult to establish an early diagnosis of MVEV infection, and there is a lack of proven therapeutic options.

Diagnosing swine flu: the inaccuracy of case definitions during the 2009 pandemic, an attempt at refinement, and the implications for future planning

Background  At the onset of the pandemic H1N1/09 influenza A outbreak in Australia, health authorities devised official clinical case definitions to guide testing and access to antiviral therapy.

Objectives  To assess the diagnostic accuracy of these case definitions and to attempt to improve on them using a scoring system based on clinical findings at presentation.

Patients/Methods  This study is a retrospective case–control study across three metropolitan Melbourne hospitals and one associated community‐based clinic during the influenza season, 2009. Patients presenting with influenza‐like illness who were tested for H1N1/09 influenza A were administered a standard questionnaire of symptomatology, comorbidities, and risk factors. Patients with a positive test were compared to those with a negative test. Logistic regression was performed to examine for correlation of clinical features with disease. A scoring system was devised and compared with case definitions used during the pandemic. The main outcome measures were the positive and negative predictive values of our scoring system, based on real‐life data, versus the mandated case definitions’.

Results  Both the devised scoring system and the case definitions gave similar positive predictive values (38–58% using ascending score groups, against 39–44% using the various case definitions). Negative predictive values were also closely matched (ranging from 94% to 73% in the respective score groups against 83–84% for the case definitions).

Conclusions  Accurate clinical diagnosis of H1N1/09 influenza A was difficult and not improved significantly by a structured scoring system. Investment in more widespread availability of rapid and sensitive diagnostic tests should be considered in future pandemic planning.

Visceral leishmaniasis due to Leishmania donovani in a patient with advanced HIV infection

An Eritrean-born man observed over an extended period had upper gastrointestinal symptoms, fever, hepatosplenomegaly and pancytopenia in the setting of advanced HIV infection and poor adherence to antiretroviral therapy. Despite thorough investigation, it was not until a repeat gastroscopic examination and gastric biopsy were performed 18 months after initial presentation that Leishmania infection was diagnosed. The species was identified by polymerase chain reaction assay as L. donovani. Physicians managing HIV-infected patients from regions where Leishmania is endemic should consider visceral leishmaniasis, even in patients who have not lived in a Leishmania-endemic region for many years.

Treatment of staphylococcal prosthetic joint infections with debridement, prosthesis retention and oral rifampicin and fusidic acid

There is growing evidence of the efficacy of treating early staphylococcal infections of prosthetic joints with surgical debridement and prosthesis retention, combined with oral antibiotic regimens that include rifampicin in combination with a fluoroquinolone. With rising rates of fluoroquinolone-resistant staphylococci, evidence concerning the efficacy of alternative combinations of antibiotics is required. Twenty patients with staphylococcal prosthetic joint infections who had been treated with surgical debridement and prosthesis retention, and a combination of rifampicin and fusidic acid were analysed. The mean duration of symptoms before initial debridement was 16 (range 2-75) days. The median time of follow-up was 32 (range 6-76) months. Treatment failure occurred in two patients. The cumulative risk of treatment failure after 1 year was 11.76% (95% CI 3.08-39.40%). Two patients had their treatment changed because of nausea. Ten of 11 patients with infections involving methicillin-resistant Staphylococcus aureus had successful outcomes. Debridement without prosthesis removal, in combination with rifampicin and fusidic acid treatment, was effective and should be considered for patients with early staphylococcal prosthetic joint infections, including those with infections involving fluoroquinolone-resistant organisms.