Anthony McDonald

Epidemiology, clinical features and diagnosis of Mycobacterium ulcerans in an Australian population.

Objective: To describe the epidemiology, clinical features and diagnosis of Mycobacterium ulcerans infection occurring on the Bellarine Peninsula in Victoria.

Successful outcomes with oral fluoroquinolones combined with rifampicin in the treatment of Mycobacterium ulcerans: an observational cohort study.

Background The World Health Organization currently recommends combined streptomycin and rifampicin antibiotic treatment as first-line therapy for Mycobacterium ulcerans infections. Alternatives are needed when these are not tolerated or accepted by patients, contraindicated, or neither accessible nor affordable. Despite in vitro effectiveness, clinical evidence for fluoroquinolone antibiotic use against Mycobacterium ulcerans is lacking. We describe outcomes and tolerability of fluoroquinolone-containing antibiotic regimens for Mycobacterium ulcerans in south-eastern Australia. Methodology/Principal Findings Analysis was performed of prospectively collected data including all primary Mycobacterium ulcerans infections treated at Barwon Health between 1998 and 2010. Medical treatment involved antibiotic use for more than 7 days; surgical treatment involved surgical excision of a lesion. Treatment success was defined as complete lesion healing without recurrence at 12 months follow-up. A complication was defined as an adverse event attributed to an antibiotic that required its cessation. A total of 133 patients with 137 lesions were studied. Median age was 62 years (range 3–94 years). 47 (34%) had surgical treatment alone, and 90 (66%) had combined surgical and medical treatment. Rifampicin and ciprofloxacin comprised 61% and rifampicin and clarithromycin 23% of first-line antibiotic regimens. 13/47 (30%) treated with surgery alone failed treatment compared to 0/90 (0%) of those treated with combination medical and surgical treatment (p<0.0001). There was no difference in treatment success rate for antibiotic combinations containing a fluoroquinolone (61/61 cases; 100%) compared with those not containing a fluoroquinolone (29/29 cases; 100%). Complication rates were similar between ciprofloxacin and rifampicin (31%) and rifampicin and clarithromycin (33%) regimens (OR 0.89, 95% CI 0.27–2.99). Paradoxical reactions during treatment were observed in 8 (9%) of antibiotic treated cases. Conclusions Antibiotics combined with surgery may significantly increase treatment success for Mycobacterium ulcerans infections, and fluoroquinolone combined with rifampicin-containing antibiotic regimens can provide an effective and safe oral treatment option.

Corticosteroid Use for Paradoxical Reactions during Antibiotic Treatment for Mycobacterium ulcerans

Buruli or Bairnsdale Ulcer (BU) is a neglected infectious disease caused by Mycobacterium ulcerans and is characterized by necrotic cutaneous lesions. Infection is challenging to treat, and the ideal combination of surgery and antimicrobial therapy continues to evolve. M. ulcerans has been endemic to the Bellarine peninsula in Victoria, Australia, since 1998, with more than 250 cases of infection. Studies have illustrated the safety and efficacy of antimicrobial therapy [1]–[5], and our standard treatment practice has evolved over the last 15 years to comprise limited surgical debridement with combination antimicrobial therapy.

Treatment and prevention of Mycobacterium ulcerans infection (Buruli ulcer) in Australia: guideline update

Guidelines reflecting contemporary clinical practice in the management of Buruli ulcer (Mycobacterium ulcerans infection) in Australia were published in 2007. Management has continued to evolve, as new evidence has become available from randomised trials, case series and increasing clinical experience with oral antibiotic therapy. Therefore, guidelines on the diagnosis, treatment and prevention of Buruli ulcer in Australia have been updated. They include guidance on the new role of antibiotics as first‐line therapy; the shortened duration of antibiotic treatment and the use of all‐oral antibiotic regimens; the continued importance, timing and role of surgery; the recognition and management of paradoxical reactions during antibiotic treatment; and updates on the prevention of disease.

Incidence, clinical spectrum, diagnostic features, treatment and predictors of paradoxical reactions during antibiotic treatment of Mycobacterium ulcerans infections.

BackgroundParadoxical reactions from antibiotic treatment of Mycobacterium ulcerans have recently been recognized. Data is lacking regarding their incidence, clinical and diagnostic features, treatment, outcomes and risk factors in an Australian population.MethodsData was collected prospectively on all confirmed cases of M. ulcerans infection managed at Barwon Health Services, Australia, from 1/1/1998-31/12/2011. Paradoxical reactions were defined on clinical and histological criteria and cases were determined by retrospectively reviewing the clinical history and histology of excised lesions. A Poisson regression model was used to examine associations with paradoxical reactions.ResultsThirty-two of 156 (21%) patients developed paradoxical reactions a median 39 days (IQR 20-73 days) from antibiotic initiation. Forty-two paradoxical episodes occurred with 26 (81%) patients experiencing one and 6 (19%) multiple episodes. Thirty-two (76%) episodes occurred during antibiotic treatment and 10 (24%) episodes occurred a median 37 days after antibiotic treatment. The reaction site involved the original lesion (wound) in 23 (55%), was separate to but within 3 cm of the original lesion (local) in 11 (26%) and was more than 3 cm from the original lesion (distant) in 8 (19%) episodes. Mycobacterial cultures were negative in 33/33 (100%) paradoxical episodes. Post-February 2009 treatment involved more cases with no antibiotic modifications (12/15 compared with 11/27, OR 5.82, 95% CI 1.12-34.07, p = 0.02) and no further surgery (9/15 compared with 2/27, OR 18.75, 95% CI 2.62-172.73, p < 0.001). Six severe cases received prednisone with marked clinical improvement. On multivariable analysis, age ≥ 60 years (RR 2.84, 95% CI 1.12-7.17, p = 0.03), an oedematous lesion (RR 3.44, 95% CI 1.11-10.70, p=0.03) and use of amikacin in the initial antibiotic regimen (RR 6.33, 95% CI 2.09-19.18, p < 0.01) were associated with an increased incidence of paradoxical reactions.ConclusionsParadoxical reactions occur frequently during or after antibiotic treatment of M. ulcerans infections in an Australian population and may be increased in older adults, oedematous disease forms, and in those treated with amikacin. Recognition of paradoxical reactions led to changes in management with less surgery, fewer antibiotic modifications and use of prednisolone for severe reactions.

Mycobacterium ulcerans Disease: Experience with Primary Oral Medical Therapy in an Australian Cohort

Background Mycobacterium ulcerans (MU) is responsible for disfiguring skin lesions and is endemic on the Bellarine peninsula of southeastern Australia. Antibiotics have been shown to be highly effective in sterilizing lesions and preventing disease recurrences when used alone or in combination with surgery. Our practice has evolved to using primarily oral medical therapy. Methods From a prospective cohort of MU patients managed at Barwon Health, we describe those treated with primary medical therapy defined as treatment of a M. ulcerans lesion with antimicrobials either alone or in conjunction with limited surgical debridement. Results From 1/10/2010 through 31/12/11, 43 patients were treated with exclusive medical therapy, of which 5 (12%) also underwent limited surgical debridement. The median patient age was 50.2 years, and 86% had WHO category 1 and 91% ulcerative lesions. Rifampicin was combined with ciprofloxacin in 30 (70%) and clarithromycin in 12 (28%) patients. The median duration of antibiotic therapy was 56 days, with 7 (16%) receiving less than 56 days. Medication side effects requiring cessation of one or more antibiotics occurred in 7 (16%) patients. Forty-two (98%) patients healed without recurrence within 12 months, and 1 patient (2%) experienced a relapse 4 months after completion of 8 weeks of antimicrobial therapy. Conclusion Our experience demonstrates the efficacy and safety of primary oral medical management of MU infection with oral rifampicin-based regimens. Further research is required to determine the optimal and minimum durations of antibiotic therapy, and the most effective antibiotic dosages and formulations for young children.

Risk factors for recurrent Mycobacterium ulcerans disease after exclusive surgical treatment in an Australian cohort

Objective: To describe risk factors for recurrence after exclusive surgical treatment of Mycobacterium ulcerans infection.

Mycobacterium Ulcerans Treatment - Can Antibiotic Duration Be Reduced in Selected Patients?

Introduction Mycobacterium ulcerans (M. ulcerans) is a necrotizing skin infection endemic to the Bellarine Peninsula, Australia. Current treatment recommendations include 8 weeks of combination antibiotics, with adjuvant surgery if necessary. However, antibiotic toxicity often results in early treatment cessation and local experience suggests that shorter antibiotic courses may be effective with concurrent surgery. We report the outcomes of patients in the Barwon Health M. ulcerans cohort who received shorter courses of antibiotic therapy than 8 weeks. Methodology / Principal findings A retrospective analysis was performed of all M. ulcerans infections treated at Barwon Health from March 1, 1998 to July 31, 2013. Sixty-two patients, with a median age of 65 years, received < 56 days of antibiotics and 51 (82%) of these patients underwent concurrent surgical excision. Most received a two-drug regimen of rifampicin combined with either ciprofloxacin or clarithromycin for a median 29 days (IQR 21–41days). Cessation rates were 55% for adverse events and 36% based on clinician decision. The overall success rate was 95% (98% with concurrent surgery; 82% with antibiotics alone) with a 50% success rate for those who received < 14 days of antibiotics increasing to 94% if they received 14–27 days and 100% for 28–55 days (p<0.01). A 100% success rate was seen for concurrent surgery and 14–27 days of antibiotics versus 67% for concurrent surgery and < 14 days of antibiotics (p = 0.12). No previously identified risk factors for treatment failure with surgery alone were associated with reduced treatment success rates with < 56 days of antibiotics. Conclusion In selected patients, antibiotic treatment durations for M. ulcerans shorter than the current WHO recommended 8 weeks duration may be associated with successful outcomes.

Early diagnosis and treatment of necrotizing fasciitis can improve survival: an observational intensive care unit cohort study

The aim of this study was to describe the clinical characteristics, causative pathogens, clinical management and outcomes of patients presenting to a tertiary adult Australian intensive care unit (ICU) with a diagnosis of necrotizing fasciitis (NF).

Clinical Features and Risk Factors of Oedematous Mycobacterium ulcerans Lesions in an Australian Population: Beware Cellulitis in an Endemic Area

Introduction Oedematous lesions are a less common but more severe form of Mycobacterium ulcerans disease. Misdiagnosis as bacterial cellulitis can lead to delays in treatment. We report the first comprehensive descriptions of the clinical features and risk factors of patients with oedematous disease from the Bellarine Peninsula of south-eastern Victoria, Australia. Methods Data on all confirmed Mycobacterium ulcerans cases managed at Barwon Health, Victoria, were collected from 1/1/1998–31/12/2012. A multivariate logistic regression model was used to assess associations with oedematous forms of Mycobacterium ulcerans disease. Results Seventeen of 238 (7%) patients had oedematous Mycobacterium ulcerans lesions. Their median age was 70 years (IQR 17–82 years) and 71% were male. Twenty-one percent of lesions were WHO category one, 35% category two and 41% category three. 16 (94%) patients were initially diagnosed with cellulitis and received a median 14 days (IQR 9–17 days) of antibiotics and 65% required hospitalization prior to Mycobacterium ulcerans diagnosis. Fever was present in 50% and pain in 87% of patients. The WCC, neutrophil count and CRP were elevated in 54%, 62% and 75% of cases respectively. The median duration of antibiotic treatment was 84 days (IQR 67–96) and 94% of cases required surgical intervention. On multivariable analysis, there was an increased likelihood of a lesion being oedematous if on the hand (OR 85.62, 95% CI 13.69–535.70; P<0.001), elbow (OR 7.83, 95% CI 1.39–43.96; p<0.001) or ankle (OR 7.92, 95% CI 1.28–49.16; p<0.001), or if the patient had diabetes mellitus (OR 9.42, 95% CI 1.62–54.74; p = 0.02). Conclusions In an Australian population, oedematous Mycobacterium ulcerans lesions present with similar symptoms, signs and investigation results to, and are commonly mistakenly diagnosed for, bacterial limb cellulitis. There is an increased likelihood of oedematous lesions affecting the hand, elbow or ankle, and in patients with diabetes.