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Efflux pumps are proteins capable of expelling antibiotics from bacterial cells, have emerged as a major mechanism of bacterial resistance. In the ongoing pursuit to overcome and reduce bacterial resistance, novel substances are being explored as potential efflux pump inhibitors. Meldrum's acid, a synthetic molecule widely studied for its role in synthesizing bioactive compounds, holds promise in this regard. Therefore, the objective of this study is to evaluate the antibacterial activity of three derivatives of Meldrum's acid and assess their ability to inhibit efflux mechanisms, employing both in silico and in vitro approaches. The antibacterial activity of the derivatives was assessed using a broth microdilution testing method. Surprisingly, the derivatives did not exhibit direct antibacterial activity on their own. However, they displayed a significant effect in enhancing the efficacy of antibiotics, suggesting a potential role in potentiating their effects. Furthermore, fluorescence emission assays using ethidium bromide indicated that the derivatives could potentially block efflux pumps, as they exhibited fluorescence levels comparable to the positive control. To further investigate their inhibitory capacity, molecular docking studies were conducted in silico, revealing binding interactions similar to ciprofloxacin and carbonyl cyanide 3‐chlorophenylhydrazone, known efflux pump inhibitors. These findings highlight the potential of Meldrum's acid derivatives as effective inhibitors of efflux pumps. By targeting these mechanisms, the derivatives offer a promising avenue to enhance the effectiveness of antibiotics and combat bacterial resistance. This study underscores the importance of exploring novel strategies in the fight against bacterial resistance and provides valuable insights into the potential of Meldrum's acid derivatives as efflux pump inhibitors. Further research and exploration in this field are warranted to fully exploit their therapeutic potential. [ABSTRACT FROM AUTHOR]

Several environmental impacts are associated with the improper disposal of toxic metals in the environment. The bioadsorption stands out for being a cheap and easy-to-operate technique for remove those contaminants in wastewaters. When existing more than one contaminant present in the wastewater, the adsorptive study becomes complex, since there is competition between these species for the available active sites of the adsorbent. Therefore, this work aimed to study and compare the removal of Pb+2 and Cu+2 ions in aqueous solutions, both on mono- and multielementary systems, through the application of the bioadsorption technique using as the adsorbent the residues of the Caryocar coriaceum WITTM. barks. Characterization techniques like SEM–EDS, XRD, FTIR, and pHPZC were used to study the adsorbent. The results showed that all the systems follow the pseudo-second-order model, and the diffusing process was chemissoption associated with ions change. Langmuir model presented a better fit than Freundlich model. The maximum adsorptive capacity (mg g−1) obtained, for the multielementary systems, was 47.6 for Pb+2 and 20.4 for Cu+2. It was found that there was an inhibitory effect between Cu+2 and Pb+2, which resulted in a reduction of qmax values by approximately 37%, for Cu+2, and 55%, for Pb+2, compared to the monoelementary system, however, enabling the simultaneous removal of both contaminants, optimizing process time, and reflecting systems with real conditions. As a conclusion, it was found that the bark of Caryocar coriaceum WITTM. showed good adsorptive results compared to the literature and that it could be used as a adsorbent for solutions containing dissolved Pb+2 and Cu+2, for both mono- and multielemental systems. Highlights: • Caryocar coriaceum WITTM. bark was studied as an adsorbent for Cu+2 and Pb+2 metals' ions in aqueous solutions, in mono and multielement adsorption systems. • Caryocar coriaceum WITTM. bark was characterized before and after being used as an absorbent. • Caryocar coriaceum WITTM. bark could be used as an adsorbent to remove Cu+2 and Pb+2 metals' ions in aqueous solutions, enabling the noble use of these wastes before being discarded. [ABSTRACT FROM AUTHOR]

Cystic fibrosis is the most common and best known genetic disease involving a defect in transepithelial Cl- transport by mutations in the CF gene on chromosome 7, which codes for the cystic fibrosis transmembrane conductance regulator protein (CFTR). The most serious symptoms are observed in the lungs, augmenting the risk of bacterial infection. The objective of this review was to describe the bacterial pathogens colonizing patients with cystic fibrosis. A systematic search was conducted using the international bibliographic databanks SCIELO, HIGHWIRE, PUBMED, SCIRUS and LILACS to provide a useful and practical review for healthcare workers to make them aware of these microorganisms. Today, B. cepacia, P. aeruginosa and S. aureus are the most important infectious agents in cystic fibrosis patients. However, healthcare professionals must pay attention to emerging infectious agents in these patients, because they represent a potentially serious future problem. Therefore, these pathogens should be pointed out as a risk to these patients, and hospitals all over the world must be prepared to detect and combat these bacteria.