# The Cell Envelope Integrity Protein Homologue D0Y85_RS06240 of Stenotrophomonas Confers Multiantibiotic Resistance

## TL;DR

This study shows that a protein from Stenotrophomonas helps bacteria resist multiple antibiotics, offering new insights into antibiotic resistance mechanisms.

## Contribution

The study identifies D0Y85_RS06240 as a novel cell envelope protein linked to multiantibiotic resistance in Stenotrophomonas.

## Key findings

- D0Y85_RS06240 heterologous expression in E. coli conferred resistance to colistin, tetracycline, and cefixime.
- Efflux pump inhibitor NMP reduced antibiotic resistance and enhanced tetracycline's bactericidal effect.
- Molecular docking confirmed D0Y85_RS06240's ability to bind multiple antibiotics.

## Abstract

The potential role of cell envelope integrity proteins in mediating antibiotic resistance is not well understood. In this study, we investigated whether the cell envelope integrity protein D0Y85_RS06240 from the multiantibiotic resistant strain Stenotrophomonas sp. G4 mediates antibiotic resistance.

Bioinformatics analysis was conducted to identify proteins related to the D0Y85_RS06240 protein. The D0Y85_RS06240 gene was heterologously expressed in Escherichia coli, both antibiotic MICs and the effect of efflux pump inhibitors on antibiotic MICs were determined by the broth microdilution method. A combination of antibiotic and efflux pump inhibitor was used to investigate bacterial killing kinetics, and binding of D0Y85_RS06240 to antibiotic molecules was predicted by molecular docking analysis.

Sequence homology analysis revealed that D0Y85_RS06240 was related to cell envelope integrity proteins. The D0Y85_RS06240 heterologous expression strains were resistant to multiple antibiotics, including colistin, tetracycline, and cefixime. However, the efflux pump inhibitor N-methylpyrrolidone (NMP) reduced the antibiotic MICs of the D0Y85_RS06240 heterologous expression strain, and bacterial killing kinetics revealed that NMP enhanced the bactericidal rate of tetracycline to the drug-resistant bacteria. Molecular docking analysis indicated that D0Y85_RS06240 could bind colistin, tetracycline, and cefixime.

The cell envelope integrity protein D0Y85_RS06240 in Stenotrophomonas sp. G4 mediates multiantibiotic resistance. This study lays the foundation for an in-depth analysis of D0Y85_RS06240-mediated antibiotic resistance mechanisms and the use of D0Y85_RS06240 as a target for the treatment of multiantibiotic-resistant bacterial infections.