The Calgary Biofilm Device: New Technology for Rapid Determination of Antibiotic Susceptibilities of Bacterial Biofilms

Abstract

Determination of the MIC, based on the activities of antibiotics against planktonic bacteria, is the standard assay for antibiotic susceptibility testing. Adherent bacterial populations (biofilms) present with an innate lack of antibiotic susceptibility not seen in the same bacteria grown as planktonic populations. The Calgary Biofilm Device (CBD) is described as a new technology for the rapid and reproducible assay of biofilm susceptibilities to antibiotics. The CBD produces 96 equivalent biofilms for the assay of antibiotic susceptibilities by the standard 96-well technology. Biofilm formation was followed by quantitative microbiology and scanning electron microscopy. Susceptibility to a standard group of antibiotics was determined for National Committee for Clinical Laboratory Standards (NCCLS) reference strains: Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, andStaphylococcus aureus ATCC 29213. Growth curves demonstrated that biofilms of a predetermined size could be formed on the CBD at specific time points and, furthermore, that no significant difference (P > 0.1) was seen between biofilms formed on each of the 96 pegs. The antibiotic susceptibilities for planktonic populations obtained by the NCCLS method or from the CBD were similar. Minimal biofilm eradication concentrations, derived by using the CBD, demonstrated that for biofilms of the same organisms, 100 to 1,000 times the concentration of a certain antibiotic were often required for the antibiotic to be effective, while other antibiotics were found to be effective at the MICs. The CBD offers a new technology for the rational selection of antibiotics effective against microbial biofilms and for the screening of new effective antibiotic compounds.

In vitro and ex vivo systems at the forefront of infection modeling and drug discovery

“…To address this concern, a variation of the MTP based system, called the "Calgary Biofilm Device (CBD)" (Fig. 1A), was introduced, in which biofilms are formed on lids with pegs that fit into the wells of the microtiter plate containing bacteria [73]. The CBD has been successfully used as a rapid and reproducible assay to screen for biofilm susceptibility to antibiotics.…”

Metal resistance in Candida biofilms

“…Biofilms were grown in the MBEC TM Physiology and Genetics assay (MBEC BioProducts Inc., Edmonton, Canada; http://www.mbec.ca). This method was previously described by Ceri et al (1999Ceri et al ( , 2001, and uses a plastic lid with 96 pegs that fits inside a standard 96-well microplate. This device and the cultivation methods were modified to facilitate the growth of yeast biofilms.…”

“…Although the tolerance of bacterial biofilms to metal ions has been documented in a number of studies (Teitzel & Parsek, 2003;Harrison et al, 2004aHarrison et al, , b, 2005b, no study to date has specifically examined the susceptibility of yeast biofilms to metals. This study employed a high-throughput method previously developed by our research group to examine the susceptibility of bacterial biofilms to antibiotics, disinfectants and metals (Ceri et al, 1999;Harrison et al, 2004a). Here we modified this technique to examine the ability of C. tropicalis biofilms to survive exposure to a diverse array of toxic metal ions.…”

Diagnóstico microbiológico de la colonización-infección broncopulmonar en el paciente con fibrosis quística

“…Dentro de la complejidad que presenta el estudio de sensibilidad en biopelículas los protocolos que má s se han utilizado son los que han derivado del dispositivo descrito por Ceri et al 37 , conocido como sistema de Calgary. El crecimiento de las bacterias se realiza en placas de microtitulació n, idé nticas a las que se utilizan para el estudio de sensibilidad por microdilució n, cerradas con unas tapas que contienen pú as (o pinchos) que se insertan en cada uno de los pocillos y sobre los que se desarrolla el biofilm.…”