Bacteria is becoming more resistant to antibiotics making future diseases more deadly and harder to treat.

The global rise in antibiotic resistance poses a significant threat, diminishing the efficacy of common antibiotics against widespread bacterial infections. The 2022 Global Antimicrobial Resistance and Use Surveillance System (GLASS) report highlights alarming resistance rates among prevalent bacterial pathogens. Median reported rates in 76 countries of 42% for third-generation cephalosporin-resistant E. coli and 35% for methicillin-resistant Staphylococcus aureus are a major concern. For urinary tract infections caused by E. coli, 1 in 5 cases exhibited reduced susceptibility to standard antibiotics like ampicillin, co-trimoxazole, and fluoroquinolones in 2020. This is making it harder to effectively treat common infections. Klebsiella pneumoniae, a common intestinal bacterium, also showed elevated resistance levels against critical antibiotics. Increased levels of resistance potentially lead to heightened utilization of last-resort drugs like carbapenems, for which resistance is in turn being observed across multiple regions. As the effectiveness of these last-resort drugs is compromised, the risks increase of infections that cannot be treated. Projections by the Organization for Economic Cooperation and Development (OECD) indicate an anticipated twofold surge in resistance to last-resort antibiotics by 2035, compared to 2005 levels, underscoring the urgent need for robust antimicrobial stewardship practices and enhanced surveillance coverage worldwide.

Diseases can cause extinction. Proven on a small scale in Nature.

McCallum 12 Professor Hamish McCallum is the Director of the Centre for Planetary Health and Food Security at Griffith. He is an infectious disease ecologist with a particular interest in modelling the dynamics, impact and transmission of parasites and pathogens in wildlife populations. This research has two broad applications: in conservation biology and in managing zoonotic pathogens. He was the senior member of a team awarded the Eureka prize for Environmental Research in 2011 for work on Tasmanian Devil Facial Tumour and was awarded the Vice Chancellor’s award for research leadership in 2019. (Hamish, October 19, “Disease and the dynamics of extinction”, National Library of Medicine,)

Invading infectious diseases can, in theory, lead to the extinction of host populations, particularly if reservoir species are present or if disease transmission is frequency-dependent. The number of historic or prehistoric extinctions that can unequivocally be attributed to infectious disease is relatively small, but gathering firm evidence in retrospect is extremely difficult. Amphibian chytridiomycosis and Tasmanian devil facial tumour disease (DFTD) are two very different infectious diseases that are currently threatening to cause extinctions in Australia. These provide an unusual opportunity to investigate the processes of disease-induced extinction and possible management strategies. Both diseases are apparently recent in origin. Tasmanian DFTD is entirely host-specific but potentially able to cause extinction because transmission depends weakly, if at all, on host density. Amphibian chytridiomycosis has a broad host range but is highly pathogenic only to some populations of some species. At present, both diseases can only be managed by attempting to isolate individuals or populations from disease. Management options to accelerate the process of evolution of host resistance or tolerance are being investigated in both cases. Anthropogenic changes including movement of diseases and hosts, habitat destruction and fragmentation and climate change are likely to increase emerging disease threats to biodiversity and it is critical to further develop strategies to manage these threats. The role of infectious disease in the history of human society is well known. In contrast, until the pioneering work of Anderson and May [1–4] in the late 1970s, the perception among most ecologists was that ‘well-adapted’ parasites do not harm their hosts. The role of infectious disease as a driver of host population dynamics was therefore underappreciated, and infectious diseases or parasites were rarely considered as significant extinction threatening processes. In theory, however, simple models show that parasites and infectious diseases may, in some circumstances, be capable of being significant contributors to extinction [5]. From first principles, a population declines when there are more deaths than there are births and extinction occurs when there continue to be more deaths than births even as the population declines towards zero. It is therefore necessary to first distinguish between situations in which infectious disease may reduce population size to such an extent that other factors may lead to extinction and cases in which infectious disease contributes to there being an excess of deaths over births even in a vanishingly small population.