Emergent Bacteria in Cystic Fibrosis:In VitroBiofilm Formation and Resilience under Variable Oxygen Conditions

Abstract

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 occur in vivo in the mucus of CF patients. Two CF-emergent bacterial species, Inquilinus limosus and Dolosigranulum pigrum, and the major pathogen Pseudomonas aeruginosa were studied in terms of biofilm development and antibiotic susceptibilities under in vitro atmospheres with different oxygen availabilities. All species were able to develop in vitro biofilms under different oxygen-available environments, with D. pigrum accumulating 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 organisms I. limosus and D. pigrum on 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.

An in vitro model of catheter-associated urinary tract infections to investigate the role of uncommon bacteria on the Escherichia coli microbial consortium

“…Hence, a polymicrobial community is established on the surface of an urinary catheter, in particular when the urinary catheter remains in the patient for several weeks or months [3][4][5][6]. Recently, some studies have studied the role of some uncommon bacteria in clinical infections and have highlighted their role in shaping the overall behavior of the microbial biofilm [15,17,28,29].…”

Insights into Cystic Fibrosis Polymicrobial Consortia: The Role of Species Interactions in Biofilm Development, Phenotype, and Response to In-Use Antibiotics

“…Because CF infection is no longer viewed as being caused by a single pathogen, antibiotics, often used to target a small group of species recognized as key CF pathogens, are generally ineffective when other atypical species are present (Lopes et al, 2012, 2014) failing in many cases (Leekha et al, 2011). …”

Discriminating typical and atypical cystic fibrosis‐related bacteria by multiplex PNA‐FISH

“…It is suggested that the preponderance of D. pigrum in the biofilm could be decisive to decline I. limosus , with the first species also triggering sensitivity to a large number of antibiotics to the whole biofilm (Lopes et al, unpublished data). The ability of these emergent species to develop multidrug‐resistant biofilms alone and in modulating social interactions with P. aeruginosa was addressed before (Lopes et al, , ). Altogether, these results highlight the significance of emergent species in CF infection and therapeutics, and should not be therefore, disregarded.…”