Project description:Incomplete antibiotic removal in pharmaceutical wastewater treatment plants (PWWTPs) could lead to the development and spread of antibiotic-resistant bacteria (ARBs) and genes (ARGs) in the environment, posing a growing public health threat. In this study, two multiantibiotic-resistant bacteria, Ochrobactrum intermedium (N1) and Stenotrophomonas acidaminiphila (N2), were isolated from the sludge of a PWWTP in Guangzhou, China. The N1 strain was highly resistant to ampicillin, cefazolin, chloramphenicol, tetracycline, and norfloxacin, while the N2 strain exhibited high resistance to ampicillin, chloramphenicol, and cefazolin. Whole-genome sequencing revealed that N1 and N2 had genome sizes of 0.52 Mb and 0.37 Mb, respectively, and harbored 33 and 24 ARGs, respectively. The main resistance mechanism in the identified ARGs included efflux pumps, enzymatic degradation, and target bypass, with the N1 strain possessing more multidrug-resistant efflux pumps than the N2 strain (22 vs 12). This also accounts for the broader resistance spectrum of N1 than of N2 in antimicrobial susceptibility tests. Additionally, both genomes contain numerous mobile genetic elements (89 and 21 genes, respectively) and virulence factors (276 and 250 factors, respectively), suggesting their potential for horizontal transfer and pathogenicity. Overall, this research provides insights into the potential risks posed by ARBs in pharmaceutical wastewater and emphasizes the need for further studies on their impact and mitigation strategies.
Project description:Cationic antimicrobial peptides (CAPs) are promising novel alternatives to conventional antibacterial agents, but the overlap in resistance mechanisms between small-molecule antibiotics and CAPs is unknown. Does evolution of antibiotic resistance decrease (cross-resistance) or increase (collateral sensitivity) susceptibility to CAPs? We systematically addressed this issue by studying the susceptibilities of a comprehensive set of antibiotic resistant Escherichia coli strains towards 24 antimicrobial peptides. Strikingly, antibiotic resistant bacteria frequently showed collateral sensitivity to CAPs, while cross-resistance was relatively rare. We identified clinically relevant multidrug resistance mutations that simultaneously elevate susceptibility to certain CAPs. Transcriptome and chemogenomic analysis revealed that such mutations frequently alter the lipopolysaccharide composition of the outer cell membrane and thereby increase the killing efficiency of membrane-interacting antimicrobial peptides. Furthermore, we identified CAP-antibiotic combinations that rescue the activity of existing antibiotics and slow down the evolution of resistance to antibiotics. Our work provides a proof of principle for the development of peptide based antibiotic adjuvants that enhance antibiotic action and block evolution of resistance.
Project description:The aim of this experiment was to determine if the development of resistance to antibiotics can be driven by the concentration and speciation of Cu. Experimental setup was designed to investigate two hypotheses for which two strains of Gram- bacteria have been selected: - Do TE enhance AR in resistant bacteria? Resistant strain: Bioluminescent Pseudomonas aeruginosa PAO1 (Xen41, Tetracycline resistant) - Do TE induce AR in sensitive bacteria? Sensitive strain: Pseudomonas aeruginosa PAO1 (Wild Type)
Project description:This phase II, randomized pilot trial studies the effect of the consumption of foods made with resistant starch compared to foods made with corn starch on biomarkers that may be related to colorectal cancer progression in stage I-III colorectal cancer survivors. Foods made with resistant starch may beneficially influence markers of inflammation, insulin resistance, and the composition of gut bacteria in colorectal cancer survivors.