SugE belongs to the small multidrug resistance (SMR) protein family involved in tributyltin (TBT) biodegradation and bioremediation by alkaliphilic Stenotrophomonas chelatiphaga HS2

iChip increases the success of cultivation of TBT-resistant and TBT-degrading bacteria from estuarine sediment

Standard methods of microbial cultivation only enable the isolation of a fraction of the total environmental bacteria. Numerous techniques have been developed to increase the success of isolation and cultivation in the laboratory, some of which derive from diffusion chambers. In a diffusion chamber, environmental bacteria in agar medium are put back in the environment to grow as close to their natural conditions as possible, only separated from the environment by semi-permeable membranes. In this study, the iChip, a device that possesses hundreds of mini diffusion chambers, was used to isolate tributyltin (TBT) resistant and degrading bacteria. IChip was shown to be efficient at increasing the number of cultivable bacteria compared to standard methods. TBT-resistant strains belonging to Oceanisphaera sp., Pseudomonas sp., Bacillus sp. and Shewanella sp. were identified from Liverpool Dock sediment. Among the isolates in the present study, only members of Pseudomonas sp. were able to use TBT as a sole carbon source. It is the first time that members of the genus Oceanisphaera have been shown to be TBT-resistant. Although iChip has been used in the search for molecules of biomedical interest here we demonstrate its promising application in bioremediation.

Microbial resistance: The role of efflux pump superfamilies and their respective substrates

The microorganism resistance to antibiotics has become one of the most worrying issues for science due to the difficulties related to clinical treatment and the rapid spread of diseases. Efflux pumps are classified into six groups of carrier proteins that are part of the different types of mechanisms that contribute to resistance in microorganisms, allowing their survival. The present study aimed to carry out a bibliographic review on the superfamilies of carriers in order to understand their compositions, expressions, substrates, and role in intrinsic resistance. At first, a search for manuscripts was carried out in the databases Medline, Pubmed, ScienceDirect, and Scielo, using as descriptors: efflux pump, expression, pump inhibitors and efflux superfamily. For article selection, two criteria were taken into account: for inclusion, those published between 2000 and 2020, including textbooks, and for exclusion, duplicates and academic collections. In this research, 139,615 published articles were obtained, with 312 selected articles and 7 book chapters that best met the aim. From the comprehensive analysis, it was possible to consider that the chromosomes and genetic elements can contain genes encoding efflux pumps and are responsible for multidrug resistance. Even though this is a well-explored topic in the scientific community, understanding the behavior of antibiotics as substrates that increase the expression of pump-encoding genes has challenged medicine. This review study succinctly summarizes the most relevant features of these systems, as well as their contribution to multidrug resistance.