An artificial medium mimicking human sputum
This medium had been developed for laboratory use to culture respiratory bacteria in an environment that closely mimics human lung sputum.
Respiratory bacteria such as P. aeruginosa, H. influenzae and S. aureus grow in human sputum or associated epithelial cells; therefore understanding their growth characteristics in sputum is an important step to understanding in vivo infection.
Currently laboratories grow respiratory bacteria on blood agar or enriched broth media such as Luria broth or Brain Heart Infusion Broth. These are general purpose media and are not specific to the level of nutrients and composition of any in vivo growth site. Bacteria express particular genes/proteins depending on the composition of their environment.
Bacterial gene expression can vary considerably in different types of lab media and this is often a problem for understanding which virulence genes and proteins are significant in bacterial pathogenesis in order to be targeted with therapeutic drugs.
An artificial sputum-containing medium have been made previously by Sriramulu et al (2005), while a totally synthetic sputum medium has also been made (Palmer et al 2007).
Based on the knowledge on the chemical and nutritional composition of normal sputum, cystic fibrosis sputum and other artificial sputum media, we have refined and produced a media that closely mimics cystic fibrosis sputum.
This media has been validated with P. aeruginosa genomic expression studies and by comparison of the growth characteristics of P. aeruginosa in this medium with those known to occur in cystic fibrosis sputum (Fung et al 2010).
This media provides an ideal growth environment for respiratory bacteria from sputum and as such will help clinical and research scientists to look at the expression of specific genes/proteins in an “almost in-vivo” setting.
Furthermore, bacterial characteristics such as biofilm formation, tight microcolony formation, anaerobic growth and virulence factor expression can be monitored as they would be expected to occur in human sputum
- Dr Jim Manos
- A/Prof Barbara Rose
- A/Prof Cynthia Whitchurch
- Dr Lynne Turnbull