Objective: To determine if exogenous neurotrophins can prevent spiral ganglion neuron degeneration in the rat cochlea. Background: The loss of hair cells resulting in sensorineural hearing loss also leads to the secondary degeneration of spiral ganglion neurons. The effectiveness of cochlear implantation in patients with profound sensorineural hearing loss relies in part on the survival of spiral ganglion neurons; therefore, any therapy that can prevent or halt the loss of these neurons would be of potential clinical benefit. Previous research has shown that intracochlear infusion with neurotrophins can provide trophic support to SGNs in deafened guinea pigs. Whether this effect is seen in other species remains to be determined. Methods: After documenting the rate of spiral ganglion neuron degeneration after ototoxic deafening, we investigated the trophic effects of exogenous brain-derived neurotrophic factor (BDNF) on rat spiral ganglion neurons. The left cochleae of profoundly deafened rats were implanted with a drug delivery system connected to a mini-osmotic pump. BDNF or artificial perilymph was infused for 28 days; then the cochleae were prepared for histological study. Results: Treatment with BDNF led to a statistically significant increase in spiral ganglion neuron density and a highly significant increase in spiral ganglion neuron soma area compared with artificial perilymph-treated and untreated deafened cochleae. Conclusion: The study has demonstrated the trophic advantage of exogenous BDNF in the mature rat cochlea and provides confidence that spiral ganglion neuron rescue after sensorineural hearing loss with exogenous BDNF may have clinical application.

Extended-spectrum beta-lactamase-expressing Gram-negative bacilli (ESBL-GNB) now commonly cause community-acquired infections, including urinary tract infections (UTI), and represent a challenge for practitioners in choosing empirical antibiotics. The aim of this study was to describe the epidemiology and clinical characteristics of UTIs/bacteriuria due to ESBL-GNB in Australia. At a single-site tertiary referral hospital, 100 cases with UTIs/bacteriuria due to ESBL-GNB were matched to 100 cases where UTIs/bacteriuria were caused by organisms matching the ESBL bacterial species that had routine susceptibility to antibiotics. Potential risk factors for ESBL-GNB UTI/bacteriuria and differences in clinical outcomes were identified. Length of admission prior to positive sample (odds ratio (OR) 1.3, p = 0.03, per week), exposure to antibiotics (OR 5.7, p < 0.001), return from overseas travel (OR 6.5, p = 0.002), and nursing home residency (OR 4.2, p = 0.03) were identified as risk factors associated with ESBL-GNB UTI/bacteriuria in the multivariate analysis. In addition, ESBL-GNB-infected cases subsequently had a longer inpatient stay (median 6 vs. 2 days, p = 0.002) and were admitted to the intensive care unit more frequently (28/100 vs. 8/100, p < 0.001). Our results emphasize the need for culture of a mid-stream urine specimen prior to commencing antibacterials, especially in patients with the risk factors identified herein associated with ESBL-GNB UTI/bacteriuria.

Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in Asia, causing ⁓100 000 cases and 25 000 deaths annually. ¹ JEV is transmitted by Culex mosquitoes in an enzootic cycle involving waterbirds (reservoir hosts) and/or pigs (amplifying hosts); humans are incidental dead-end hosts. Whilst most human infections are asymptomatic, severe disease occurs in ⁓1 per 250 infections and may rapidly progress to encephalitis with an estimated case fatality rate of 20–30%. ² Amongst survivors, ⁓30–50% have long-term neurologic sequelae. ³ No specific treatment exists, but supportive care improves outcomes.

An outbreak of cutaneous sporotrichosis occurred in the Darwin region of the Northern Territory (NT) in 2014. We aimed to determine the source and risk factors associated with the outbreak and describe the clinical spectrum of cases seen. Epidemiological investigation of cases of cutaneous sporotrichosis identified through the Royal Darwin Hospital was undertaken to investigate risk factors and potential sources of infection. Data were collected through chart review and individual patient interviews. Environmental investigation followed identification of a common risk factor. Nine confirmed cases of cutaneous sporotrichosis caused by Sporothrix schenckii were identified with onset of symptoms between April and July 2014. Patients were aged 29 to 70 years and seven were male (78 %). Two strains of S. schenckii were identified, neither of which have been previously documented. One common risk factor was identified: all patients were occupational or recreational gardeners, with each reporting exposure to mulching hay, originating from a single NT farm. Local environmental health officers visited the farm and the owners confirmed that the implicated hay had been stored over the monsoon season and had been affected by rain. Storage of hay over the wet season was a new practice. This constitutes the third reported outbreak of S. schenckii sporotrichosis attributable to contaminated hay in Australia and the first outbreak of sporotrichosis in the NT. This outbreak prompted public health interventions, including distribution of information to general practitioners, farmers and suppliers in the Top End. Media reporting led to the identification and treatment of an additional case. Local practitioners should remain alert to the possibility of further occurrences of sporotrichosis.

Nocardia is an opportunistic pathogen that can cause life-threatening disease. We aimed to characterize the epidemiological, microbiological, and clinical features of nocardiosis in the tropical north of Australia. We conducted a retrospective cohort study of nocardiosis diagnosed between 1997 and 2014. Population-based incidences were calculated using district population data. Clinically significant nocardiosis was identified in 61 patients. The unadjusted population-based annual incidence of nocardiosis was 2.02 (95% confidence interval [CI], 1.55–2.60) per 100000 people and was 1.7 (95% CI, .96–2.90) fold higher in Indigenous compared with non-Indigenous persons (P = .027). Of 61 patients, 47 (77%) had chronic lung disease, diabetes, and/or hazardous alcohol consumption; 22 (36%) were immunocompromised; and 8 (13%) had no identified comorbidities. Disease presentations included pulmonary (69%; 42 of 61), cutaneous (13%; 8 of 61), and disseminated nocardiosis (15%; 9 of 61). The most commonly identified species were Nocardia asteroides and Nocardia cyriacigeorgica (each 11%). Linezolid was the only antimicrobial to which isolates were universally susceptible; 89% (48 of 54), 60% (32 of 53), and 48% (26 of 54) of isolates were susceptible to trimethoprim-sulfamethoxazole, ceftriaxone, and imipenem, respectively. Eighteen patients (30%) required intensive care unit (ICU) admission, and 1-year mortality was 31%. The incidence of nocardiosis in tropical Australia is amongst the highest reported globally. Nocardiosis occurs in both immunocompromised and immunocompetent hosts, and it is associated with high rates of ICU admission, 1-year mortality, and resistance to commonly recommended antimicrobials. Diagnosis should be considered in patients with consistent clinical features, particularly if they are Indigenous or have chronic lung disease.