Dynamics of Antimicrobial Resistance Carriage in Koalas (Phascolarctos Cinereus) and Pteropid Bats (Pteropus Poliocephalus) Before, During and After Wildfires

In the 2019-2020 summer, wildfires decimated the Australian bush environment and impacted wildlife species, including koalas (Phascolarctos cinereus) and grey headed flying fox pups (Pteropid bats, Pteropus poliocephalus). Consequently, hundreds of koalas and thousands of bat pups entered wildlife hospitals with fire-related injuries/illness, where some individuals received antimicrobial therapy. This study investigated the dynamics of antimicrobial resistance (AMR) in pre-fire, fire-affected and post-fire koalas and Pteropid bat pups. PCR and DNA sequencing were used to screen DNA samples extracted from faeces (koalas and bats) and cloacal swabs (koalas) for class 1 integrons, a genetic determinant of AMR, and to identify integron-associated antibiotic resistance genes. Class 1 integrons were detected in 25.5% of koalas (68 of 267) and 59.4% of bats (92 of 155). Integrons contained genes conferring resistance to aminoglycosides, trimethoprim and beta-lactams. Samples were also screened for blaTEM (beta-lactam) resistance genes, which were detected in 2.6% of koalas (7 of 267) and 25.2% of bats (39 of 155). Integron occurrence was significantly higher in fire-affected koalas in-care compared to wild pre-fire koalas (P < 0.0001). Integron and blaTEM occurrence were not significantly different in fire-affected bats compared to pre-fire bats (P > 0.05), however, their occurrence was significantly higher in fire-affected bats in-care compared to wild fire-affected bats (P < 0.0001 and P = 0.0488 respectively). The observed shifts of AMR dynamics in wildfire-impacted species flags the need for judicious antibiotic use when treating fire-affected wildlife to minimise unwanted selective pressure and negative treatment outcomes associated with carriage of resistance genes and antibiotic resistant bacteria.

Wellness Warriors: a qualitative exploration of healthcare staff learning to support their colleagues in the aftermath of the Australian bushfires

PURPOSE

Healthcare staff are on the frontline during disasters despite any personal adversity and vicarious trauma they may be experiencing. Wellness Warrior training is a post-disaster intervention developed in response to the 2019-2020 Australian bushfires to support staff in a rural hospital located on the South Coast of New South Wales, Australia.

METHOD

This study explored the experiences and perspectives of 18 healthcare staff who were trained to provide emotional and peer support to their colleagues in the aftermath of a crisis. All the Wellness Warriors participated in semi-structured interviews between March and April 2020. Data were analysed using the reflexive thematic approach.

RESULTS

Healthcare staff reported developing interpersonal skills around deep listening and connecting with others which allowed for hearing the core of their colleagues' concerns. The training also helped staff to feel differently about work and restored their faith in healthcare leadership.

CONCLUSION

Wellness Warrior training provided staff with knowledge and skills to support their colleagues in the aftermath of a natural disaster and later during the COVID-19 pandemic. As such, these findings suggest that peer support programs such as Wellness Warriors could be one way healthcare organisations can attempt to alleviate the psychological impact of natural disasters.

Carriage of antibiotic resistance genes to treatments for chlamydial disease in koalas (Phascolarctos cinereus): A comparison of occurrence before and during catastrophic wildfires

Growing reports of diverse antibiotic resistance genes in wildlife species around the world symbolises the extent of this global One Health issue. The health of wildlife is threatened by antimicrobial resistance in situations where wildlife species develop disease and require antibiotics. Chlamydial disease is a key threat for koalas in Australia, with infected koalas frequently entering wildlife hospitals and requiring antibiotic therapy, typically with chloramphenicol or doxycycline. This study investigated the occurrence and diversity of target chloramphenicol and doxycycline resistance genes (cat and tet respectively) in koala urogenital and faecal microbiomes. DNA was extracted from 394 urogenital swabs and 91 faecal swabs collected from koalas in mainland Australia and on Kangaroo Island (KI) located 14 km off the mainland, before (n = 145) and during (n = 340) the 2019-2020 wildfires. PCR screening and DNA sequencing determined 9.9% of samples (95%CI: 7.5% to 12.9%) carried cat and/or tet genes, with the highest frequency in fire-affected KI koalas (16.8%) and the lowest in wild KI koalas sampled prior to fires (6.5%). The diversity of cat and tet was greater in fire-affected koalas (seven variants detected), compared to pre-fire koalas (two variants detected). Fire-affected koalas in care that received antibiotics had a significantly higher proportion (p < 0.05) of cat and/or tet genes (37.5%) compared to koalas that did not receive antibiotics (9.8%). Of the cat and/or tet positive mainland koalas, 50.0% were Chlamydia-positive by qPCR test. Chloramphenicol and doxycycline resistance genes in koala microbiomes may contribute to negative treatment outcomes for koalas receiving anti-chlamydial antibiotics. Thus a secondary outcome of wildfires is increased risk of acquisition of cat and tet genes in fire-affected koalas that enter care, potentially exacerbating the already significant threat of chlamydial disease on Australia's koalas. This study highlights the importance of considering impacts to wildlife health within the One Health approach to AMR and identifies a need for greater understanding of AMR ecology in wildlife.

Impact of bushfires on Australian livestock health, welfare and carcase quality

The 2019/2020 Australian bushfires were unprecedented in terms of total area burned and impact on livestock and wildlife populations. However, there is currently limited literature available relating the consequences of bushfire or smoke exposure to livestock health, welfare, and carcase quality. A retrospective cross-sectional study was conducted using historical monitoring data from a Meat Standards Australia (MSA) accredited abattoir located on the mid-north coast of New South Wales, Australia. The spatiotemporal association between exposure to bushfire smoke (specifically the duration of the bushfires, distance from closest bushfire, annual bushfire season, proportion of the property of origin burned during the bushfires and time frame since exposure to bushfires) and effects on carcase meat quality metrics and pathology were measured, by building linear, generalised linear and cumulative link mixed models. Our findings indicate that hot carcase weight increased as the distance between the property of origin and the closest bushfire became greater and decreased with exposure to bushfires of longer duration or when greater proportions of the property of origin were burnt during bushfires. Subcutaneous rib fat of carcases also increased with an increasing distance of properties from the closest recorded bushfire and decreased with exposure to bushfires during the 2019/2020 season. Higher meat colour scores (darker meat colour) were associated with exposure to bushfires during the 2019/2020 season and exposure to bushfires of longer durations. There was only a weak association between increasing distance to the closest bushfire and higher marbling scores. Evidence of pneumonia in carcases was associated with exposure to bushfires of longer duration, specifically increasing risk of pneumonia was associated with fires of longer durations. Greater periods of time since exposure (i.e., >6 months) to bushfires were also associated with a higher risk of evidence of pneumonia at the time of processing. With increasing incidence of bushfires in Australia forecasted as a result of climate change, there is an urgent need to understand the impact of bushfires on livestock, to limit the effects on livestock health and mitigate the risk of significant socioeconomic impacts to the livestock industry. By providing a greater understanding of the impact of bushfires, the findings of this study can support producers to make informed decisions to mitigate the effects of bushfires on livestock health and carcase meat quality.

Wildfires cause rapid changes to estuarine benthic habitat

Estuaries are one of the most valuable biomes on earth. Although humans are highly dependent on these ecosystems, anthropogenic activities have impacted estuaries worldwide, altering their ecological functions and ability to provide a variety of important ecosystem services. Many anthropogenic stressors combine to affect the soft sedimentary habitats that dominate estuarine ecosystems. Now, due to climate change, estuaries and other marine areas might be increasingly exposed to the emerging threat of megafires. Here, by sampling estuaries before and after a megafire, we describe impacts of wildfires on estuarine benthic habitats and justify why megafires are a new and concerning threat to coastal ecosystems. We (1) show that wildfires change the fundamental characteristics of estuarine benthic habitat, (2) identify the factors (burnt intensity and proximity to water's edge) that influence the consequences of fires on estuaries, and (3) identify relevant indicators of wildfire impact: metals, nutrients, and pyrogenic carbon. We then discuss how fires can impact estuaries globally, regardless of local variability and differences in catchment. In the first empirical assessment of the impact of wildfires on estuarine condition, our results highlight indicators that may assist waterway managers to empirically detect wildfire impacts in estuaries and identify catchment factors that should be included in fire risk assessments for estuaries. Overall, this study highlights the importance of considering fire threats in current and future estuarine and coastal management.

Ecological consequences of Australian "Black Summer" (2019-20) fires: A synthesis of Australian Commonwealth Government report findings

During the summer of 2019-2020, more than 15 000 wildfires burned up to 19 million hectares of forest and woodland regions across Australia. These fires culminated in the worst Australian fire season on record, producing what has come to be known as the Australian "Black Summer." The fires have been described as an "ecological disaster," but the scale of the impacts is so extensive that the full ecological consequence may take years to assess. In the immediate aftermath of the Black Summer fires, two major national investigations were established by the Australian Commonwealth Government. By reviewing reports produced by these two investigations, high-level insights into the scale of the ecological consequences of the Black Summer fires have been obtained and are summarized here. Through these insights, the urgency for action to reduce the occurrence, and improve the management, of future comparable fire events is made clear. Integr Environ Assess Manag 2021;17:1136-1140. © 2021 SETAC.

Local synergies and antagonisms between meteorological factors and air pollution: A 15-year comprehensive study in the Sydney region

Associated with rapid urbanization and escalation of bushfire events, Sydney has experienced significant air quality degradation in the XXI century. In this study, we present a 15-year retrospective analysis on the influence of individual meteorological factors on major air pollutants (NO₂, O₃, PM₁₀ and PM_2.5) at 14 different sites in Greater Sydney and Illawarra. By applying a newly developed "zooming in" approach to long-term ground-based data, we disclose general, seasonal, daily and hourly patterns while increasing the level of spatial associativity. We provide evidence on the pivotal role played by urbanization, sprawling dynamics, global warming and bushfires on local meteorology and air pollution. We strike associations between temperature and O₃, both as average trends and extremes, on account of increasing heat island effects. The role of wind in a coastal-basin environment, influenced by a vast desert biome inland, is investigated. A steady trend towards stagnation is outlined, boosted by enhanced urban roughness and intensified heat island circulation. Relative humidity is also crucial in the modulation between NO₂ and O₃. With a sharp tendency towards drier and hotter microclimates, NO₂ levels dropped by approximately 50% over the years at all locations, while O₃'s median levels almost doubled in the last 10 years. Further, O₃ and PMs shifted towards more frequent extreme events, strongly associated with the exacerbation of bushfire events. Such results suggest an urgent need to prioritize emission control, building air tightness improvement and urban heat mitigation, towards a future-proof governance in Sydney and similar regions in the world.

A novel approach to the development of 1-hour threshold concentrations for exposure to particulate matter during episodic air pollution events

Episodic air pollution events that occur because of wildfires, dust storms and industrial incidents can expose populations to particulate matter (PM) concentrations in the thousands of µg m^-3. Such events have increased in frequency and duration over recent years, with this trend predicted to continue in the short to medium term because of climate warming. The human health cost of episodic PM events can be significant, and inflammatory responses are measurable even after only a few hours of exposure. Consequently, advice for the protection of public health should be available as quickly as possible, yet the shortest averaging period for which PM exposure guideline values (GVs) are available is 24-h. To address this problem, we have developed a novel approach, based on Receiver Operating Characteristic (ROC) statistical analysis, that derives 1-h threshold concentrations that have a probabilistic relationship with 24-h GVs. The ROC analysis was carried out on PM₁₀ and PM_2.5 monitoring data from across the US for the period 2014-2019. Validation of the model against US Air Quality Index (AQI) 24-h breakpoint concentrations for PM showed that the maximum-observed 1-h PM concentration in any rolling 24-h averaging period is an excellent predictor of exceedances of 24-h GVs.

Emission factors and composition of PM2.5 from laboratory combustion of five Western Australian vegetation types

This study investigated the emission of PM₁₀ and PM_2.5 (particulates with diameters of less than 10 µm and 2.5 µm, respectively) and the chemical composition of PM_2.5 from laboratory combustion of five Australian vegetation types (three grasslands, a woodland and a forest). A mix of plants representative of Banksia (woodland) and Jarrah (forest) and three types of grasses (Spinifex - Triodia basedowii; Kimberley grass - Sehima nervosum and Heteropogon contortus; and an invasive grass (Veldt) - Ehrharta calycina) were burnt in 9 combustion conditions comprised of 3 fuel moisture levels (dry, moist, wet) and 3 air flow rates (no, low and high flow). PM (particulate matter) samples were collected onto filters and measured using gravimetric analysis. PM_2.5 was then extracted and analyzed for water-soluble metals and polycyclic aromatic hydrocarbons (PAH) concentrations. The largest proportion of PM₁₀ (98%) from vegetation fires was PM_2.5. Banksia yielded the highest PM_2.5 emission factor (EF), followed by Jarrah and Spinifex. Veldt grass combustion generated significantly higher emissions of PM_2.5 compared with the other two grass types. High moisture contents and flow rates resulted in larger emissions of PM_2.5. A strong correlation (R² = 0.84) was observed between the EF for PM_2.5 and combustion efficiency, suggesting higher PM emission with lower combustion efficiencies. Potassium and sodium were the most abundant PM_2.5-bound water soluble metals, accounting for more than 97% of the total mass of metals analyzed. PAHs were found in significant concentrations, including the carcinogenic benzo(a)pyrene. Pyrene and fluoranthene were the most abundant PAHs detected, accounting for nearly 40% mass of the total PAHs. Indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene ratio (IND/IND + BghiP) appeared to be produced in a diagnostic ratio that indicated that the PAHs were derived from vegetation fires rather than other sources of emissions. The EF for PM_2.5 and its chemical composition (water-soluble metals and PAHs) were strongly influenced by the type of vegetation burned. The results presented in this study could be useful in predicting the risks of human health effects on firefighters and the public who may be exposed to regular bushfires in Australia.