Expression of antimicrobial peptide Cecropin P1 in Saccharomyces cerevisiae and its antibacterial and antiviral activity in vitro

BACKGROUND: Cecropin P1, acting as an antimicrobial, has a broad-spectrum antibacterial activity with some antiviral and antifungal properties. It is a promising natural alternative to antibiotics which is originally isolated from the pig intestinal parasitic nematode Ascaris suum. Many studies have shown that Cecropin P1 is helpful for the prevention or treatment of clinical diseases. Therefore, it is very necessary to establish a safe, nontoxic, and efficient expression method of Cecropin P1. RESULTS: The results indicated that the recombinant protein was about 5.5 kDa showed by Tricine­SDS­ PAGE and Western blot. And Cecropin P1 was efficiently secreted and expressed after 12 h of induction, with an increasing yield over the course of the induction. Its maximum concentration was 7.83 mg/L after concentration and purification. In addition, in vitro experiments demonstrated that Cecropin P1 not only exerted a strong inhibitory effect on Escherichia coli, Salmonella sp., Shigella sp., and Pasteurella sp., but also displayed an antiviral activity against PRRSV NADC30-Like strain. CONCLUSIONS: Collectively, the strategy of expressing Cecropin P1 in Saccharomyces cerevisiae is harmless, efficient, and safe for cells. In addition, the expressed Cecropin P1 has antiviral and antibacterial properties concurrently.

Plasmid-mediated mcr-1 gene in acinetobacter baumannii and pseudomonas aeruginosa: first report from pakistan

Abstract INTRODUCTION: The increased use of colistin against infections caused by Acinetobacter baumannii and Pseudomonas aeruginosa has resulted in colistin resistance. The purpose of this study was to detect plasmid-mediated mcr-1 gene in colistin-resistant A. baumannii and P. aeruginosa isolates. METHODS: A total of 146 clinical isolates of A. baumannii (n = 62) and P. aeruginosa (n = 84) were collected from the four largest tertiary care hospitals in Peshawar, Pakistan. All bacterial isolates were phenotypically screened for multidrug resistance using the Kirby-Baur disc diffusion method. The minimum inhibitory concentration (MIC) of colistin in all isolates was phenotypically performed using dilution methods. mcr-1 gene was detected through polymerase chain reaction and the nucleotide sequence of amplicon was determined using Sanger sequencing. RESULTS: Approximately 96.7% A. baumannii and 83.3% P. aeruginosa isolates were resistant to multiple antibiotics. Colistin resistance was found in 9.6% (6/62) of A. baumannii and 11.9% (10/84) of P. aeruginosa isolates. Among 16 colistin resistant isolates, the mcr-1 gene was detected in one A. baumannii (1.61% of total isolates; 16.6% of colistin resistant isolates) and one P. aeruginosa strain (1.19% of total isolates; 10% of colistin resistant isolates). Nucleotide BLAST showed 98-99% sequence similarity to sequences of the mcr-1 gene in GenBank. CONCLUSIONS: Our study reports, for the first time, the emergence of plasmid-mediated mcr-1-encoded colistin resistance in multidrug resistant strains of A. baumannii and P. aeruginosa. Further large scales studies are recommended to investigate the prevalence of this mode of resistance in these highly pathogenic bacteria.