Table 6.

ESBL detection techniques

Technique typeTest Advantages Disadvantages Reference(s)
Clinical microbiology Standard NCCLS interpretive criteria Easy to use, performed in every lab ESBLs not always “resistant” 78, 111
NCCLS ESBL confirmatory testEasy to use and interpret Sensitivity depends on choice of oxyimino-cephalosporin 111
Double-disk approximation testEasy to use, easy to interpret Distance of disk placement for optimal sensitivity not standardized 76, 169, 71
Three-dimensional test Sensitive, easy to interpret Not specific for ESBLS, labor intensive 169
Etest ESBL stripsEasy to use Not always easy to interpret, not as sensitive as double-disk test 183
Vitek ESBL test Easy to use, easy to interpret Reduced sensitivity 149, 164
Molecular detection DNA probes Specific for gene family (e.g., TEM or SHV) Labor intensive, cannot distinguish between ESBLs and non-ESBLs, cannot distinguish between variants of TEM or SHV 7, 55,70
PCR Easy to perform, specific for gene family (e.g., TEM or SHV) Cannot distinguish between ESBLs and non-ESBLs, cannot distinguish between variants of TEM or SHV 42, 90, 116
Oligotyping Detects specific TEM variants Requires specific oligonucleotide probes, labor intensive, cannot detect new variants 117
PCR-RFLP Easy to perform, can detect specific nucleotide changes Nucleotide changes must result in altered restriction site for detection 116
PCR-SSCP Can distinguish between a number of SHV variants Requires special electrophoresis conditions 106, 107
LCR Can distinguish between a number of SHV variants Requires a large number of oligonucleotide primers 80
Nucleotide sequencing The gold standard, can detect all variants Labor intensive, can be technically challenging, can be difficult to interpret manual methods 25