Emergent Bacteria in Cystic Fibrosis:In VitroBiofilm Formation and Resilience under Variable Oxygen Conditions
Concurrent to conventional bacterial pathogens, unusual microbes are emerging from cystic fibrosis (CF) airways. Nonetheless, little is known about the contribution of these newly microbes to the resilience of CF-associated biofilms, particularly under variable-oxygen concentrations that are known to occurin vivoin the mucus of CF patients. Two CF-emergent bacterial species,Inquilinus limosusandDolosigranulum pigrum, and the major pathogenPseudomonas aeruginosawere studied in terms of biofilm development and antibiotic susceptibilities underin vitroatmospheres with different oxygen availabilities. All species were able to developin vitrobiofilms under different oxygen-available environments, withD. pigrumaccumulating high amounts of biomass and respiratory activities. When established, biofilms were of difficult eradication, with antibiotics losing their effectiveness in comparison with the corresponding planktonic populations. Surprisingly, biofilms of each emergent organism displayed multidrug resistance under aerobic environments, enduring even in low-oxygen atmospheres. This study suggests a potential prospect on the impact of nonconventional organismsI. limosusandD. pigrumon CF lung infections, demonstrating capacity to adapt to biofilm mode of life under restricted-oxygen atmospheres resembling CF airways, which may ultimately endanger the efficacy of currently used antibiotic regimens.