AUTHOR=Habib Gul , Gul Haji , Ahmad Prevez , Hayat Azam , Rehman Mujaddad Ur , Mohamed Moussa Ihab , Elansary Hosam O. 

TITLE=Teicoplanin associated gene tcaA inactivation increases persister cell formation in Staphylococcus aureus

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1241995

DOI=10.3389/fmicb.2023.1241995

ISSN=1664-302X

ABSTRACT=Staphylococcus aureus is part of human normal flora and is widely associated with hospital acquired bacteremia. S. aureus has shown a diverse array of resistance to environmental stresses and antibiotics. Methicillin resistant S. aureus (MRSA) is on the high priority list of new antibiotics discovery and glycopeptides are considered the last drug of choice against MRSA. S. aureus has developed resistance against glycopeptides and the emergence of vancomycin intermediate resistant, vancomycin resistant, and teicoplanin resistant strains were globally reported. The tcaRAB is known as the S. aureus glycopeptide resistance operon that is associated with glycopeptide resistance. Here, for the first time, tcaRAB roles in S. aureus persister cells formation, and ΔtcaA dependent persisters ability of resuscitation of bacterial population was explored. We recovered a clinical strain of MRSA from a COVID-19 patient which showed a high level of resistance to teicoplanin, vancomycin, and methicillin. Whole genome RNA sequencing revealed that the tcaRAB operon expression was altered followed by high expression of glyS and sgtB. The RNA-seq data revealed a significant decrease in tcaA (P = 0.008) and tcaB (P = 0.04) expression while tcaR was not significantly altered. We knockdown the tcaA, tcaB, and tcaR by CRISPR-dCas9 and the results showed that when tcaA was suppressed by dCas9, a significant increase was witnessed in persister cells while tcaB suppression did not induce persistence. The results were further evaluated by creating a tcaA mutant that showed ΔtcaA formed a significant increase in persisters in comparison to the wild type. Based on our findings, we concluded that tcaA is the gene that increased persister cells and glycopeptide resistance and could be a potential therapeutic target in S. aureus.