The aetiology and clinical characteristics of cryptococcal infections in Far North Queensland, tropical Australia

Microbiological and Clinical Features of Patients with Cellulitis in Tropical Australia: Disease Severity Assessment and Implications for Clinical Management

Australian guidelines for the treatment of cellulitis are informed by data from temperate, metropolitan centers. It is uncertain if these guidelines are equally applicable in tropical Australia, where the population, access to healthcare, and array of potential pathogens are quite different. This retrospective study examined adults admitted to Cairns Hospital in tropical Queensland, Australia, who were treated with intravenous antibiotics for a principal diagnosis of cellulitis in 2019. The study aimed to describe the epidemiological, clinical, and microbiological findings in these cases and the resulting implications for patient management. There were 305 episodes of cellulitis; a potential pathogen was identified in 93/305 (30%), most commonly Staphylococcus aureus (45/93, 48%) or Group A Streptococcus (16/93, 17%). There was one case of Burkholderia pseudomallei. Initial treatment was most commonly with narrow spectrum β-lactam antibiotics with flucloxacillin prescribed in 170/305 (56%) and cefazolin prescribed in 74/305 (26%). Overall, 4/305 (1%) died or were admitted to the intensive care unit (ICU) within 30 days, 123/305 (40%) had an inpatient stay >48 hours, and 63/305 (21%) were readmitted to hospital within 30 days. Every patient who subsequently died or required ICU admission had an elevated early warning score (EWS ≥3) on admission. An EWS ≥3 on admission also predicted an inpatient stay of >48 hours (odds ratio [OR]: 3.2, 95% CI: 1.7-6.0; P <0.001) and 30-day readmission (OR: 2.3, 95% CI: 1.2-4.6; P = 0.01). The etiology of cellulitis in tropical Queensland, Australia, is very similar to that seen in temperate regions, enabling the use of standard management algorithms for patients with cellulitis in the region.

Advancing cryptococcal treatment: The role of nanoparticles in mitigating antifungal resistance

Cryptococcus, a ubiquitous and formidable fungal pathogen, contributes to a substantial global disease burden, with nearly 250,000 cases and 181,000 fatalities attributed to cryptococcal meningitis annually worldwide. The invasive nature of Cryptococcus presents significant challenges in treatment and management, as it mostly affects vulnerable populations, including HIV patients, organ transplant recipients, pregnant women, and elderly individuals. Moreover, these difficulties are exacerbated by the development of antifungal resistance, which emphasizes the need for efficient control measures. In this context, research efforts focusing on infection control and novel therapeutic strategies become paramount. Nanoparticle-based therapies emerge as a solution, offering advanced antifungal properties and improved efficacy. Developing effective treatment options requires understanding the complex landscape of cryptococcal infections and the innovative potential of nanoparticle-based therapies. This review highlights the urgent need for novel strategies to combat the growing threat posed by antifungal resistance while offering insights into the intricate realm of cryptococcal infections, particularly focusing on the promising role of nanoparticle-based therapies.

The Incidence, Aetiology and Clinical Course of Serious Infections Complicating Biological and Targeted Synthetic Disease-Modifying Antirheumatic Drug Therapy in Patients with Rheumatoid Arthritis in Tropical Australia

Introduction: Patients receiving biological and targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) for rheumatological conditions are at an increased risk of serious, potentially life-threatening, infection. However, the incidence, aetiology, and clinical course of serious infection in patients receiving b/tsDMARDs in tropical settings are incompletely defined. Methods: We retrospectively reviewed all patients with rheumatoid arthritis receiving b/tsDMARDs between October 2012 and October 2021, at Cairns Hospital in tropical Australia. The incidence, aetiology, and clinical course of serious infections (those requiring admission to hospital or parenteral antibiotics) were determined. Results: 310 patients had 1468 patient years of b/tsDMARD therapy during the study period; 74/310 (24%) had 147 serious infections translating to an overall risk of 10.0 episodes of serious infection per 100 patient years. The respiratory tract (50/147, 34%) and skin (37/147, 25%) were the most frequently affected sites. A pathogen was identified in 59/147 (40%) episodes and was most commonly Staphylococcus aureus (24/147, 16%). Only 2/147 (1%) were confirmed "tropical infections": 1 case of Burkholderia pseudomallei and 1 case of mixed B. pseudomallei and community-acquired Acinetobacter baumannii infection. Overall, 13/147 (9%) episodes of serious infection required Intensive Care Unit admission (0.9 per 100-patient years of b/tsDMARD therapy) and 4/147 (3%) died from their infection (0.3 per 100-patient years of b/tsDMARD therapy). The burden of comorbidity and co-administration of prednisone were the strongest predictors of death or a requirement for ICU admission. Conclusions: The risk of serious infection in patients taking b/tsDMARDs in tropical Australia is higher than in temperate settings, but this is not explained by an increased incidence of traditional tropical pathogens.

Melioidosis masquerading as malignancy in tropical Australia; lessons for clinicians and implications for clinical management

Melioidosis is a life-threatening, emerging infectious disease caused by the environmental bacterium Burkholderia pseudomallei. Melioidosis is hyperendemic in tropical Australia and southeast Asia, however the disease is increasingly encountered beyond these regions. Early diagnosis is essential as the infection has a case-fatality rate of up to 50 %. Melioidosis most commonly involves the lungs, although almost any organ can be affected. Most patients present acutely but an insidious presentation over weeks to months is also well described. We present a case series of 7 patients from tropical Australia whom local clinicians initially believed to have cancer ‒ most commonly lung cancer ‒ only for further investigation to establish a diagnosis of melioidosis. All 7 patients had comorbidities that predisposed them to developing melioidosis and all survived, but their delayed diagnosis resulted in 3 receiving anti-cancer therapies that resulted in significant morbidity. The study emphasises the importance of thorough diagnostic evaluation and repeated collection of microbiological samples. It is hoped that our experience will encourage other clinicians ‒ in the appropriate clinical context ‒ to consider melioidosis as a potential explanation for a patient's presentation, expediting its diagnosis and the initiation of potentially life-saving therapy.

Cryptococcal Meningitis: Differences between Patients with and without HIV-Infection

Background: Cryptococcal meningitis is one of the most devastating infections, particularly in HIV-infected individuals. The increased use of immunosuppressants led to an increase in the incidence of cryptococcosis in HIV-uninfected individuals. This study aimed to compare the characteristics between groups. Methods: This retrospective cohort study was conducted from 2011 to 2021 in northern Thailand. Individuals diagnosed with cryptococcal meningitis aged ≥15 years were enrolled onto the study. Results: Out of 147 patients, 101 were individuals infected with HIV and 46 were non-infected. Factors associated with being infected with HIV included age < 45 years (OR 8.70, 95% CI 1.78–42.62), white blood cells < 5000 cells/cu.mm. (OR 7.18, 95% CI 1.45–35.61), and presence of fungemia (OR 5.86, 95% CI 1.17–42.62). Overall, the mortality rate was 24% (18% in HIV-infected vs. 37% in HIV-uninfected individuals, p-value = 0.020). Factors associated with mortality included concurrent pneumocystis pneumonia (HR 5.44, 95% CI 1.55–19.15), presence of alteration of consciousness (HR 2.94, 95% CI 1.42–6.10), infection caused by members of C. gattii species complex (HR 4.19, 95% CI 1.39–12.62), and anemia (HR 3.17, 95% CI 1.17–8.59). Conclusions: Clinical manifestations of cryptococcal meningitis differed between patients with and without HIV-infection in some aspects. Increasing awareness in physicians of this disease in HIV-uninfected individuals may prompt earlier diagnosis and timely treatment.

What's New in Cryptococcus gattii: From Bench to Bedside and Beyond

Cryptococcus species are a major cause of life-threatening infections in immunocompromised and immunocompetent hosts. While most disease is caused by Cryptococcus neoformans, Cryptococcus gattii, a genotypically and phenotypically distinct species, is responsible for 11-33% of global cases of cryptococcosis. Despite best treatment, C. gattii infections are associated with early mortality rates of 10-25%. The World Health Organization's recently released Fungal Priority Pathogen List classified C. gattii as a medium-priority pathogen due to the lack of effective therapies and robust clinical and epidemiological data. This narrative review summarizes the latest research on the taxonomy, epidemiology, pathogenesis, laboratory testing, and management of C. gattii infections.

The seasonality of infections in tropical Far North Queensland, Australia: A 21-year retrospective evaluation of the seasonal patterns of six endemic pathogens

An understanding of the seasonality of infections informs public health strategies and assists clinicians in their management of patients with undifferentiated illness. The seasonality of infections is driven by a variety of environmental and human factors; however, the role of individual climatic factors has garnered much attention. This study utilises Poisson regression models to assess the seasonality of six important infections in tropical Australia and their association with climatic factors and severe weather events over a 21-year period. Melioidosis and leptospirosis showed marked wet season predominance, while more cases of rickettsial disease and cryptococcosis were seen in cooler, drier months. Staphylococcus aureus infections were not seasonal, while influenza demonstrated inter-seasonality. The climate did not significantly change during the 21 years of the study period, but the incidence of melioidosis and rickettsial disease increased considerably, highlighting the primacy of other factors-including societal inequality, and the impact of urban expansion-in the incidence of these infections. While anthropogenic climate change poses a threat to the region-and may influence the burden of these infections in the future-this study highlights the fact that, even for seasonal diseases, other factors presently have a greater effect on disease incidence. Public health strategies must also target these broader drivers of infection if they are to be effective.