Phenotypic Switching of Staphylococcus aureus Mu50 Into a Large Colony Variant Enhances Heritable Resistance Against β-Lactam Antibiotics

Yajun Sun; Miaomiao Liu; Mingze Niu; Xin Zhao

doi:10.3389/fmicb.2021.709841

Phenotypic Switching of Staphylococcus aureus Mu50 Into a Large Colony Variant Enhances Heritable Resistance Against β-Lactam Antibiotics

Front Microbiol. 2021 Oct 7:12:709841. doi: 10.3389/fmicb.2021.709841. eCollection 2021.

Authors

Yajun Sun¹, Miaomiao Liu¹, Mingze Niu¹, Xin Zhao^{1

2}

Affiliations

¹ College of Animal Science and Technology, Northwest A&F University, Yangling, China.
² Department of Animal Science, McGill University, Montreal, QC, Canada.

Abstract

Phenotypic heterogeneity within a bacterial population may confer new functionality and allow microorganisms to adapt to fluctuating environments. Previous work has suggested that Staphylococcus aureus could form small colony variants to avoid elimination by therapeutic antibiotics and host immunity systems. Here we show that a reversible non-pigment large colony morphology (Mu50∆lcpA-LC) was observed in S. aureus Mu50 after knocking out lcpA, coding for the LytR-CpsA-Psr family A protein. Mu50∆lcpA-LC increased resistance to β-lactam antibiotics, in addition, the enlarged cell size, enhanced spreading ability on solid medium, and reduced biofilm formation, suggesting better abilities for bacterial expansion. Moreover, the expression of spa encoding protein A was significantly increased in Mu50∆lcpA-LC. This study shows that besides the small colony variants, S. aureus could fight against antibiotics and host immunity through phenotype switching into a large colony variant.

Keywords: MRSA; Staphylococcus aureus; large colony; lcpA; phenotype switching; spa; β-Lactams.