Direct analysis of bacterial viability in endotracheal tube biofilm from a pig model of methicillin-resistant<i>Staphylococcus aureus</i>pneumonia following antimicrobial therapy

Fernández-Barat, Laia; Bassi, Gianluigi Li; Ferrer, Miquel; Bosch, Anna; Calvo, Marı́a; Vila, Jordi; Gabarrús, Albert; Martínez-Olondris, Pilar; Rigol, Montse; Esperatti, Mariano; Luque, Néstor; Torres, Antoni

doi:10.1111/j.1574-695x.2012.00961.x

Cited by 26 publications

(27 citation statements)

References 46 publications

(54 reference statements)

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“…Then, the ETT was longitudinally cut open, and a 3-cm-long section of the dependent half was dissected to quantify Gram-negative and Gram-positive aerobic pathogens as previously reported [25]. In two animals of each study group, two 1-cm-long hemi-sections of the ETT were dissected to visually confirm presence of ETT biofilm through confocal scanning laser microscopy (CSLM) [26] and scanning electron microscopy (SEM) [25]. Biofilm stage was assessed through SEM micrographs analysis, as previously described [15].…”

Section: Methodsmentioning

confidence: 99%

Endotracheal tube biofilm translocation in the lateral Trendelenburg position

et al. 2015

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IntroductionLaboratory studies demonstrated that the lateral Trendelenburg position (LTP) is superior to the semirecumbent position (SRP) in the prevention of ventilator-associated pulmonary infections. We assessed whether the LTP could also prevent pulmonary colonization and infections caused by an endotracheal tube (ETT) biofilm.MethodsEighteen pigs were intubated with ETTs colonized by Pseudomonas aeruginosa biofilm. Pigs were positioned in LTP and randomized to be on mechanical ventilatin (MV) up to 24 hour, 48 hour, 48 hour with acute lung injury (ALI) by oleic acid and 72 hour. Bacteriologic and microscopy studies confirmed presence of biofilm within the ETT. Upon autopsy, samples from the proximal and distal airways were excised for P.aeruginosa quantification. Ventilator-associated tracheobronchitis (VAT) was confirmed by bronchial tissue culture ≥3 log colony forming units per gram (cfu/g). In pulmonary lobes with gross findings of pneumonia, ventilator-associated pneumonia (VAP) was confirmed by lung tissue culture ≥3 log cfu/g.ResultsP.aeruginosa colonized the internal lumen of 16 out of 18 ETTs (88.89%), and a mature biofilm was consistently present. P.aeruginosa colonization did not differ among groups, and was found in 23.6% of samples from the proximal airways, and in 7.1% from the distal bronchi (P = 0.001). Animals of the 24 hour group never developed respiratory infections, whereas 20%, 60% and 25% of the animals in group 48 hour, 48 hour-ALI and 72 hour developed P.aeruginosa VAT, respectively (P = 0.327). Nevertheless, VAP never developed.ConclusionsOur findings imply that during the course of invasive MV up to 72 hour, an ETT P.aeruginosa biofilm hastily colonizes the respiratory tract. Yet, the LTP compartmentalizes colonization and infection within the proximal airways and VAP never develops.

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Section: Methodsmentioning

confidence: 99%

Endotracheal tube biofilm translocation in the lateral Trendelenburg position

et al. 2015

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“…8) [63,64] (BIII). After extubation, the ETT inner surface can also be processed in the CML for microscopic examination of the presence of biofilms [43,[64][65][66] (Fig. 8) (BIII).…”

Section: (Aiii)mentioning

confidence: 99%

ESCMID∗ guideline for the diagnosis and treatment of biofilm infections 2014

Høiby

Bjarnsholt

Moser

et al. 2015

Clinical Microbiology and Infection

621

536

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Biofilms cause chronic infections in tissues or by developing on the surfaces of medical devices. Biofilm infections persist despite both antibiotic therapy and the innate and adaptive defence mechanisms of the patient. Biofilm infections are characterized by persisting and progressive pathology due primarily to the inflammatory response surrounding the biofilm. For this reason, many biofilm infections may be difficult to diagnose and treat efficiently. It is the purpose of the guideline to bring the current knowledge of biofilm diagnosis and therapy to the attention of clinical microbiologists and infectious disease specialists. Selected hallmark biofilm infections in tissues (e.g. cystic fibrosis with chronic lung infection, patients with chronic wound infections) or associated with devices (e.g. orthopaedic alloplastic devices, endotracheal tubes, intravenous catheters, indwelling urinary catheters, tissue fillers) are the main focus of the guideline, but experience gained from the biofilm infections included in the guideline may inspire similar work in other biofilm infections. The clinical and laboratory parameters for diagnosing biofilm infections are outlined based on the patient's history, signs and symptoms, microscopic findings, culture-based or culture-independent diagnostic techniques and specific immune responses to identify microorganisms known to cause biofilm infections. First, recommendations are given for the collection of appropriate clinical samples, for reliable methods to specifically detect biofilms, for the evaluation of antibody responses to biofilms, for antibiotic susceptibility testing and for improvement of laboratory reports of biofilm findings in the clinical microbiology laboratory. Second, recommendations are given for the prevention and treatment of biofilm infections and for monitoring treatment effectiveness. Finally, suggestions for future research are given to improve diagnosis and treatment of biofilm infections.

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“…The BacLight Live/Dead bacterial viability kit (L-7007; Molecular Probes, Eugene, OR) was used to stain bacteria in biofilms grown on glass coverslips. The kit contains (i) Syto9, a membrane-permeable fluorophore staining both living and dead cells in green by intercalation in their DNA, and (ii) propidium iodide, which only enters damaged cells, causing an attenuation of the Syto9 signal in dead cells only and making them appear red when a dual-emission filter is used (26,27). The stain was prepared by dilution of 4 l of component A (1.67 mM Syto9 plus 1.67 mM propidium iodide) and 6 l of component B (1.67 mM syto9 plus 18.3 mM propidium iodide) into 1 ml of distilled water.…”

Section: Methodsmentioning

confidence: 99%

A Combined Pharmacodynamic Quantitative and Qualitative Model Reveals the Potent Activity of Daptomycin and Delafloxacin against Staphylococcus aureus Biofilms

Bauer

Siala

Tulkens

et al. 2013

Antimicrob Agents Chemother

116

105

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Biofilms are associated with persistence of Staphylococcus aureus infections and therapeutic failures. Our aim was to set up a pharmacodynamic model comparing antibiotic activities against biofilms and examining in parallel their effects on viability and biofilm mass. Biofilms of S. aureus ATCC 25923 (methicillin-sensitive S. aureus [MSSA]) or ATCC 33591 (methicillin-resistant S. aureus [MRSA]) were obtained by culture in 96-well plates for 6 h/24 h. Antibiotic activities were assessed after 24/48 h of exposure to concentrations ranging from 0.5 to 512 times the MIC. Biofilm mass and bacterial viability were quantified using crystal violet and the redox indicator resazurin. Biofilms stained with Live/Dead probes were observed by using confocal microscopy. Concentration-effect curves fitted sigmoidal regressions, with a 50% reduction toward both matrix and viability obtained at sub-MIC or low multiples of MICs against young biofilms for all antibiotics tested. Against mature biofilms, maximal efficacies and potencies were reduced, with none of the antibiotics being able to completely destroy the matrix. Delafloxacin and daptomycin were the most potent, reducing viability by more than 50% at clinically achievable concentrations against both strains, as well as reducing biofilm depth, as observed in confocal microscopy. Rifampin, tigecycline, and moxifloxacin were effective against mature MRSA biofilms, while oxacillin demonstrated activity against MSSA. Fusidic acid, vancomycin, and linezolid were less potent overall. Antibiotic activity depends on biofilm maturity and bacterial strain. The pharmacodynamic model developed allows ranking of antibiotics with respect to efficacy and potency at clinically achievable concentrations and highlights the potential utility of daptomycin and delafloxacin for the treatment of biofilm-related infections.S taphylococcus aureus is a major human pathogen, implicated in both hospital-and community-acquired infections. In addition to the increase in antibiotic resistance that often limits therapeutic options, pathogenic bacteria can adapt and survive in specific microenvironments that are also associated with therapeutic failure and recurrence or persistence of infection. Among them, biofilms play a significant role in persistent infections formed on the surface of implanted medical devices and in deep tissues (1-3). Biofilms are complex aggregates of bacteria encased in an extracellular matrix made of polymeric substances like DNA, polysaccharides, teichoic acids, and proteins (4). Biofilms protect bacteria from host defense and antibiotics, allowing them to remain dormant for long periods in the host, and represent a reservoir for resistance development and for bacterial dissemination within the body. Biofilm formation and growth are finely regulated and are accompanied by metabolic changes that could also affect bacterial response to antibiotics (5).Antibiotic activity against staphylococcal biofilms has been studied in a large variety of in vitro or animal models in an attempt ...

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Direct analysis of bacterial viability in endotracheal tube biofilm from a pig model of methicillin-resistantStaphylococcus aureuspneumonia following antimicrobial therapy

Cited by 26 publications

References 46 publications

Endotracheal tube biofilm translocation in the lateral Trendelenburg position

Endotracheal tube biofilm translocation in the lateral Trendelenburg position

ESCMID∗ guideline for the diagnosis and treatment of biofilm infections 2014

A Combined Pharmacodynamic Quantitative and Qualitative Model Reveals the Potent Activity of Daptomycin and Delafloxacin against Staphylococcus aureus Biofilms

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