Bacteria become highly tolerant to antibiotics when nutrients are limited. The inactivity of antibiotic targets caused by starvation-induced growth arrest is thought to be a key mechanism producing tolerance. Here we show that the antibiotic tolerance of nutrient-limited and biofilm Pseudomonas aeruginosa is mediated by active responses to starvation, rather than by the passive effects of growth arrest. The protective mechanism is controlled by the starvation-signaling stringent response (SR), and our experiments link SR-mediated tolerance to reduced levels of oxidant stress in bacterial cells. Furthermore, inactivating this protective mechanism sensitized biofilms by several orders of magnitude to four different classes of antibiotics and markedly enhanced the efficacy of antibiotic treatment in experimental infections.
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http://dx.doi.org/10.1126/science.1211037 | DOI Listing |
Keystone engineers profoundly influence microbial communities by altering their shared environment, often by modifying key resources. Here, we show that in an antibiotic-treated microbial community, bacterial spread is controlled by keystone engineering affecting dispersal- an effect hidden in well-mixed environments. Focusing on two pathogens, non-motile Klebsiella pneumoniae and motile Pseudomonas aeruginosa, we found that both tolerate a β-lactam antibiotic, with Pseudomonas being more resilient and dominating in well-mixed cultures.
View Article and Find Full Text PDFBiofilm
June 2025
CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
Antibiotics are central to managing airway infections in cystic fibrosis (CF), yet current treatments often fail due to the presence of biofilms, settling down the need for seeking therapies targeting biofilms. This study aimed to investigate the antibiofilm activity of aspartic acid and its potential as an adjuvant to tobramycin against biofilms formed by mucoid and small colony variant (SCV) tobramycin tolerant strain. We assessed the effect of aspartic acid on both surface-attached and suspended biofilms within CF artificial mucus and investigated the synergistic impact of combining it with non-lethal tobramycin concentrations.
View Article and Find Full Text PDFJ Oncol Pharm Pract
January 2025
Department of Pharmacy, SSM Health Saint Louis University Hospital, Saint Louis, MO, USA.
Background: Patients post hematopoietic stem cell transplant (HSCT) are highly susceptible to infection (CDI). Exposure to antibiotic treatment, chemotherapeutic disruption to bacterial microbiome, immunosuppressive therapy, and prolonged hospitalizations synergistically contribute to the risk of CDI and its recurrence. The purpose of this study is to assess if the adjunctive administration of bezlotoxumab decreases the rate of recurrent CDI in patients post-HSCT.
View Article and Find Full Text PDFAm J Emerg Med
January 2025
Department of Pharmacy, Sarasota Memorial Health Care System, 1700 S Tamiami Trail, Sarasota, FL 34239, USA.
Background: Patient-reported penicillin allergies are frequently encountered in the emergency department (ED), which often lead to non-beta-lactam antibiotic use despite beta-lactams' place as first-line therapy in most bacterial infections. The PEN-FAST clinical decision tool was developed and validated to identify patients with a low risk of true penicillin allergies that do not require formal skin testing for rechallenging. The tool consists of four questions that add up to a total score ranging from 0 to 5.
View Article and Find Full Text PDFBull Environ Contam Toxicol
January 2025
Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China.
Ciprofloxacin (CIP) and oxytetracycline (OTC) are commonly detected antibiotic species in breeding wastewater, and microalgae-based antibiotic treatment technology is an environmentally friendly and cost-effective method for its removal. This study evaluated the effects of CIP and OTC on Scenedesmus sp. in the breeding wastewater tailwater and the removal mechanisms of antibiotics.
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