Resident microbiota affect Bordetella pertussis infectious dose and host specificity.

Before contacting host tissues, invading pathogens directly or indirectly interact with host microbiota, but the effects of such interactions on the initial stages of infection are poorly understood. Bordetella pertussis is highly infectious among humans but requires large doses to colonize rodents, unlike a closely related zoonotic pathogen, Bordetella bronchiseptica, raising important questions about the contributions of bacterial competition to initial colonization and host selection. We observed that <100 colony-forming units (CFU) of B. bronchiseptica efficiently infected mice and displaced culturable host microbiota, whereas 10 000 CFU of B. pertussis were required to colonize murine nasal cavities and did not displace host microorganisms. Bacteria isolated from murine nasal cavities but not those from the human lower respiratory tract limited B. pertussis growth in vitro, indicating that interspecies competition may limit B. pertussis colonization of mice. Further, a broad-spectrum antibiotic treatment delivered before B. pertussis inoculation reduced the infectious dose to <100 CFU, and reintroduction of single Staphylococcus or Klebsiella species was sufficient to inhibit B. pertussis colonization of antibiotic-treated mice. Together, these results reveal that resident microorganisms can prevent B. pertussis colonization and influence host specificity, and they provide rationale for manipulating microbiomes to create more-accurate animal models of infectious diseases.

Ten tips on how to care for your CKD patients in episodes of extreme heat.

Climate change is responsible for ≈75% of extreme heat events throughout the world. Heat events are associated with an increased risk for acute kidney injury, which contributes to the development of chronic kidney disease (CKD) and cardiovascular events. Patients with CKD are especially vulnerable to heat stress for a variety of reasons. A disproportionate percentage of patients with CKD live in poverty; experience homelessness, mental illness or disabilities; work outside or are elderly, all demographics that overlap with populations most susceptible to episodes of extreme heat. Therefore, it is reasonable to conclude that exposure to episodes of extreme heat can lead to the progression of CKD and increases morbidity and mortality. Given these concerns, clinicians must be prepared to promptly recognize complications of heat in CKD patients and to help patients appropriately acclimate. We propose the following tips for clinicians to effectively care for their CKD patients during extreme heat days.

Climate and the Nephrologist: The Intersection of Climate Change, Kidney Disease, and Clinical Care.

Climate change is upon us, and it will have a major effect on both kidney disease and the nephrology practice. But the converse is also true: our treatment of kidney disease has an effect on the climate. Much attention has focused on how rising temperatures can lead to acute and CKD and health exacerbations in patients with established kidney disease. Climate change is also associated with rising air pollution from wildfires and industrial wastes and infectious diseases associated with flooding and changing habitats, all of which heighten the risk of acute and CKD. Less well recognized or understood are the ways nephrology practices, in turn, contribute to still more climate change. Hemodialysis, although lifesaving, can be associated with marked water usage (up to 600 L per dialysis session), energy usage (with one 4-hour session averaging as much as one fifth of the total energy consumed by a household per day), and large clinical wastes (with hemodialysis accounting for one third of total clinical medicine-associated waste). Of note, >90% of dialysis occurs in highly affluent countries, whereas dialysis is much less available in the poorer countries where climate change is having the highest effect on kidney disease. We conclude that not only do nephrologists need to prepare for the rise in climate-associated kidney disease, they must also urgently develop more climate-friendly methods of managing patients with kidney disease.