Antibiotic Resistance Protocols (Methods in Molecular Biology)

77

demonstrated the suitability of the system to early detect the resis-

tance profiles of bacteria reference strains and multidrug-resistant

clinical isolates [ 17 ], as well as fungal strains [ 20 ]. Furthermore,

image analysis performed with the oCelloScope was shown to

allow measuring bacterial length and morphological changes and,

hence, differentiating between normal growth patterns and bacte-

rial filamentation. This would otherwise be impossible using con-

ventional optical density measurements [ 18 ]. This is particularly

relevant when testing β-lactam antibiotics such as penicillins, ceph-

alosporins, carbapenems, and monobactams, which typically induce

morphological changes in bacteria such as filamentation and sphe-

roplast formation [ 25 – 27 ].

2 Materials

●● For bacteria isolated from pure cultures: prepare sterile media

according to the strain nutritional requirements [ 28 ].

●● For urine and blood samples: use cation-adjusted Müller-

Hinton broth (MH broth) with N-tris(hydroxymethyl)methyl-

Fig. 1 Photograph of the open oCelloScope loaded with a 96-well plate. The

UniExplorer software allows setting the experiment as well as performing

online and offline image analysis along with generation of time-lapse videos.

Growth/growth inhibition curves can be inspected and compared among the

different wells

Real-Time Digital Bright Field Technology for Rapid Antibiotic Susceptibility Testing