title: Direct analysis of bacterial viability in endotracheal tube biofilm from a pig model of methicillin-resistant Staphylococcus aureus pneumonia following antimicrobial therapy.
abstract: Confocal laser scanning microscopy (CLSM) helps to observe the biofilms formed in the endotracheal tube (ETT) of ventilated subjects and to determine its structure and bacterial viability using specific dyes. We compared the effect of three different treatments (placebo, linezolid, and vancomycin) on the bacterial biofilm viability captured by CLSM. Eight pigs with pneumonia induced by methicillin-resistant Staphylococcus aureus (MRSA) were ventilated up to 96 h and treated with linezolid, vancomycin, or placebo (controls). ETT images were microscopically examined after staining with the live/dead(®)  BacLight(™)  Kit (Invitrogen, Barcelona, Spain) with a confocal laser scanning microscope. We analyzed 127 images obtained by CLSM. The median ratio of live/dead bacteria was 0.51, 0.74, and 1 for the linezolid, vancomycin, and control groups, respectively (P = 0.002 for the three groups); this ratio was significantly lower for the linezolid group, compared with the control group (P = 0.001). Images showed bacterial biofilm attached and non-attached to the ETT surface but growing within secretions accumulated inside ETT. Systemic treatment with linezolid is associated with a higher proportion of dead bacteria in the ETT biofilm of animals with MRSA pneumonia. Biofilm clusters not necessarily attach to the ETT surface.
authors.affiliation: Pneumology Department, Thorax Institute, Hospital Clínic, Barcelona, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Fernández-Barat
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Li Bassi
authors.forename: Miquel
authors.initials: M
authors.lastname: Ferrer
authors.forename: Anna
authors.initials: A
authors.lastname: Bosch
authors.forename: Maria
authors.initials: M
authors.lastname: Calvo
authors.forename: Jordi
authors.initials: J
authors.lastname: Vila
authors.forename: Albert
authors.initials: A
authors.lastname: Gabarrús
authors.forename: Pilar
authors.initials: P
authors.lastname: Martínez-Olondris
authors.forename: Montse
authors.initials: M
authors.lastname: Rigol
authors.forename: Mariano
authors.initials: M
authors.lastname: Esperatti
authors.forename: Néstor
authors.initials: N
authors.lastname: Luque
authors.forename: Antoni
authors.initials: A
authors.lastname: Torres
mesh_terms: D000081:Acetamides / Q000008:administration & dosage; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D004195:Disease Models, Animal; D004864:Equipment and Supplies / Q000382:microbiology*; D007442:Intubation, Intratracheal; D000069349:Linezolid; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000502:physiology*; D050296:Microbial Viability / Q000187:drug effects*; D018613:Microscopy, Confocal; D023303:Oxazolidinones / Q000008:administration & dosage; D010919:Placebos / Q000008:administration & dosage; D011023:Pneumonia, Staphylococcal / Q000188:drug therapy / Q000382:microbiology*; D013030:Spain; D013194:Staining and Labeling / Q000379:methods; D013552:Swine; D014640:Vancomycin / Q000008:administration & dosage
chemical_list: D000081:Acetamides; D000900:Anti-Bacterial Agents; D023303:Oxazolidinones; D010919:Placebos; D014640:Vancomycin; D000069349:Linezolid