Alterations in cell arrangements of group B streptococcus due to virulence factor expression can bias estimates of bacterial populations based on colony count measures

Thapa, Ruby, Goh, Kelvin G. K., Desai, Devika, Copeman, Ellen, Acharya, Dhruba, Sullivan, Matthew J. ORCID: https://orcid.org/0000-0003-2276-3132 and Ulett, Glen C. (2024) Alterations in cell arrangements of group B streptococcus due to virulence factor expression can bias estimates of bacterial populations based on colony count measures. Microbiology, 170 (4). ISSN 1350-0872

[thumbnail of mic001453]
Preview
PDF (mic001453) - Published Version
Available under License Creative Commons Attribution.

Download (2MB) | Preview

Abstract

Group B streptococcus (GBS) is a chain-forming commensal bacterium and opportunistic pathogen that resides in the gastrointestinal and genitourinary tract of healthy adults. GBS can cause various infections and related complications in pregnant and nonpregnant women, adults, and newborns. Investigations of the mechanisms by which GBS causes disease pathogenesis often utilize colony count assays to estimate bacterial population size in experimental models. In other streptococci, such as group A streptococcus and pneumococcus, variation in the chain length of the bacteria that can occur naturally or due to mutation can affect facets of pathogenesis, such as adherence to or colonization of a host. No studies have reported a relationship between GBS chain length and pathogenicity. Here, we used GBS strain 874391 and several derivative strains displaying longer chain-forming phenotypes (874391pgapC, 874391ΔcovR, 874391Δstp1) to assess the impact of chain length on bacterial population estimates based on the colony-forming unit (c.f.u.) assay. Disruption of GBS chains via bead beating or sonication in conjunction with fluorescence microscopy was used to compare chaining phenotypes pre-and post-disruption to detect long-and short-chain forms, respectively. We used a murine model of GBS colonization of the female reproductive tract to assess whether chaining may affect bacterial colonization dynamics in the host during chronic infection in vivo. Overall, we found that GBS exhibiting long-chain form can significantly affect population size estimates based on the colony count assay. Additionally, we found that the length of chaining of GBS can affect virulence in the reproductive tract colonization model. Collectively, these findings have implications for studies of GBS that utilize colony count assays to measure GBS populations and establish that chain length can affect infection dynamics and disease pathogenesis for this important opportunistic pathogen.

Item Type: Article
Additional Information: Funding Information: This work was supported by an Ideas Grant from the National Health and Medical Research Council (NHMRC) Australia (2021475 to G.C.U., M.J.S., and K.G.K.G).
Uncontrolled Keywords: bacteria,bacterial population estimates,cell arrangement,chain,colony-forming unit,microbiology ,/dk/atira/pure/subjectarea/asjc/2400/2404
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 22 May 2024 14:30
Last Modified: 22 May 2024 14:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/95284
DOI: 10.1099/mic.0.001453

Downloads

Downloads per month over past year

Actions (login required)

View Item View Item