Pericardial infiltration and constriction due to cardiac actinomycosis-case report.

Background: Constrictive pericarditis associated with actinomycosis infection is a rare and challenging diagnosis due to its insidious manifestation. We describe the successful treatment of pericardial infiltration and constriction due to actinomycosis. Case summary: A 50-year-old Aboriginal man presented with insidious onset of fatigue, dyspnoea, pleuritic chest pain, fever, drenching sweats, severe exercise intolerance to 50 m, and recurrent itchy skin lesions over 8 months. Prior investigations, including serial fluorodeoxyglucose (FDG)-Positron emission tomography scans, found a progressively enlarging, metabolically active anterior mediastinal mass with two biopsies on separate occasions showing no malignancy, granulomas, tuberculosis, or other pathology. Screening for infective, autoimmune, and connective tissue disease was negative. A transthoracic echocardiogram (TTE) showed fibrinous pericarditis with extensive myocardial tethering and constrictive physiology confirmed on heart catheterization. A pericardial biopsy showed inflammatory tissue only. Biopsy of a skin lesion on the buttock showed abscess formation with Splendore Hoeppli phenomenon with Gram-positive and Grocott-positive filamentous bacteria suggestive of actinomyces, confirmed by 16S rRNA gene sequencing. He was diagnosed with cardiac actinomycosis, likely due to mediastinal infiltration from a lung infection, with haematogenous spread and treated with Penicillin G with adjunctive high-dose steroid therapy with resolution of symptoms and marked improvement in TTE features of constriction after 6 weeks. Discussion: Actinomycosis is an extremely rare cause of pericardial infiltration and constriction yet highly sensitive to penicillin, highlighting the importance of accurate diagnosis. Corticosteroids are a useful adjunct to prevent chronic constrictive pericarditis and to avoid the high morbidity and mortality associated with pericardiectomy.

Varicella zoster virus: an under-recognised cause of central nervous system infections?

BACKGROUND: Varicella zoster virus (VZV) causes infections of the central nervous system (CNS) manifesting as meningitis or encephalitis. It is not commonly tested in CNS infections when compared with enterovirus (EV) and herpes simplex virus 1 (HSV-1) and 2 (HSV-2). Cerebrospinal fluid (CSF) findings of viral CNS infections are thought to be comparable. AIMS: To describe the manifestations of VZV CNS infections and ascertain if there is a predominant syndrome. To compare CSF parameters of VZV with EV, HSV-1 and HSV-2. METHODS: Retrospective study at two hospitals in Brisbane, reviewing medical notes and laboratory information system for results between January 2001 and 2019. The following parameters were recorded - disease classification, presence of rash, duration of symptoms prior to hospitalisation, length of admission, duration of antiviral treatment and 30-day mortality. CSF biochemistry, cell count (differential), PCR for VZV, EV, HSV-1 and HSV-2 were recorded. Statistical analysis of CSF parameters included Student's t-test and linear regression. RESULTS: Incidence of meningitis was comparable to encephalitis (44 vs 39%) in 52 cases. CSF protein in VZV was significantly elevated compared with EV (median 1121 vs 569 mg/L; P < 0.001) as was CSF monocytosis (96% vs 61%; P < 0.001). CSF parameters between VZV, HSV-1 and HSV-2 were similar. VZV had a higher incidence than HSV-1 or 2, while it was tested one-third as often. CONCLUSIONS: VZV CNS infection cannot be predicted by syndrome. CSF findings are markedly different from EV but like HSV-1 and 2. VZV should be routinely tested with HSV-1 and 2 when viral CNS infection is suspected.

Flucloxacillin-warfarin interaction: an under-appreciated phenomenon.

Current drug databases do not acknowledge an interaction between warfarin and flucloxacillin although case reports have indicated that flucloxacillin may increase warfarin requirement to maintain therapeutic international normalised ratio (INR). To assess whether flucloxacillin therapy leads to a significant increase in warfarin dose, we conducted a retrospective, observational, cohort study of hospital-in-the-home patients previously stable on warfarin; who were treated with flucloxacillin or other antibiotics for at least 2 weeks between June 2015 and December 2016. The outcome measured was change in average warfarin dose at two time periods: 1 week prior to antibiotic treatment and the final week of antibiotic treatment. Four cases with flucloxacillin and four comparators treated with other antibiotics met inclusion criteria. All cases treated with flucloxacillin had a clinically and statistically significant increase in warfarin dose in the final week of antibiotic treatment compared with pre-antibiotics. The warfarin dose increased by a range of 57-130% (P < 0.05). There was no significant change in warfarin dose for patients on vancomycin, benzylpenicillin or piperacillin-tazobactam. One comparator on cephazolin had a statistically significant change in warfarin dose; however, they had a sub-therapeutic INR on admission which warranted a dose increase. Due to the high risk of sequelae with sub-therapeutic anticoagulation, close INR monitoring is essential for patients on a prolonged course of flucloxacillin.

Non-rheumatic streptococcal myocarditis - warm hands, warm heart.

Acute myopericarditis in the developed world is ascribed predominantly to viral infections. Enteroviruses and adenoviruses are commonly implicated but are not routinely tested for, as the condition is self-limiting and has a good prognosis. However, we recently encountered two cases of acute myopericarditis associated with concomitant Streptococcus pyogenes [group A Streptococcus (GAS)] pharyngotonsillitis. A microbiological aetiology was pursued because of the severity of the upper respiratory tract infection and associated systemic illness rather than to explain the myopericarditis per se. We report these two cases and review the literature of this potentially under-recognized condition. In the absence of features of rheumatic fever, we hypothesize a toxin-mediated process as opposed to an immune-mediated one. We suggest that perhaps all patients with myopericarditis be assessed for GAS pharyngitis.

Daptomycin resistance in prosthetic joint infections.

Antimicrobial resistance has been problematic since the advent of antibiotics. Patients with prosthetic joint infections often require prolonged courses of antibiotic therapy, with resistance commonly being the consequence. The rapid evolution of resistance poses a serious challenge in the treatment of infections and creates a need for new agents with novel mechanisms of bactericidal activity. Daptomycin, a cyclic lipopeptide naturally produced by Streptomyces roseosporus, is a newer agent approved for use in complicated skin, soft tissue, and prosthetic joint infections. To our knowledge, this article describes the first case of daptomycin-resistant heterogenous vancomycin intermediate-resistant Staphylococcus aureus (hVISA) in an 82-year-old man undergoing elective total knee arthroplasty in Queensland, Australia, with a subsequent deep prosthetic joint infection.A literature review is presented, and the increasing number of multi-resistant organisms and their implications for orthopedics are discussed. Worldwide reports of hVISA are reviewed. To our knowledge, this is the first article to describe daptomycin resistance in prosthetic joint infections. The role of newer antimicrobial agents, such as daptomycin, and strategies to minimize antibiotic resistance are examined.

Post-operative deep sternal wound infections: making an early microbiological diagnosis.

OBJECTIVES: Early microbiological diagnosis of deep sternal wound infections (DSWI) could improve outcomes by allowing targeted antibiotic treatment. This study aims to analyse the utility of superficial sternal wound swabs and blood cultures. METHODS: From January 2005 to June 2011, 70 patients were prospectively identified with DSWI. Microbiological data were obtained retrospectively to study the correlation between superficial sternal swabs, blood cultures and the final culture results from deep sternal tissue. Colonization with multi-resistant organisms (MROs) was also analysed for its significance in the microbiological aetiology of DSWI. Patient characteristics were obtained to analyse predictors of infection caused by specific groups of organisms. RESULTS: Superficial swabs predicted the pathogen 75% of the time (n = 43). Specific to Staphylococcus aureus (n = 27), the positive predictive value of a superficial sternal swab was found to approach 100%. Colonization with MRO is 100% predictive of the pathogen in DSWI. The absence of gram-negative organisms from superficial swabs or blood cultures (n = 48) has a negative predictive value of 98%. The inclusion of blood cultures predicted the pathogen 82% of the time across all types of bacterial infections. Patient characteristics did not appear to predispose to infections caused by specific groups of organisms. CONCLUSIONS: Superficial swabs and blood cultures appear to be useful in establishing the microbiological aetiology of DSWI. Routing testing and reporting of these samples could enable early and targeted antimicrobial therapy in DSWI to improve outcomes.