Extended-spectrum β-lactamase (ESBL) gene PCR and sequencing

Registry Details

Area Health Science
Lab name Antibiotic Reference Laboratory
Lab location Kenepuru Science Centre, Porirua
Test name Extended-spectrum β-lactamase (ESBL) gene PCR and sequencing
Organisms Enterobacterales
Requested for surveillance no
Notice required yes
Routine turnaround time 20 working days for reference specimens
Culture requirements Pure culture
Media requirements A slope of any medium that supports the growth of the organism
Pre-transport requirements Ambient temperature
Transport requirements Ambient temperature
Unacceptable sample types Clinical specimens will not be accepted.
How results reported The results will state the ESBL type or CTX-M group
Referral link Form


ESBLs belong to three main families of β-lactamases: TEM, SHV and CTX-M. The CTX-M ESBLs are grouped, on the basis of sequence similarity, into five main groups: 1, 2, 8, 9 and 25. To identify a specific ESBL, sets of consensus primers, which amplify all TEM genes, all SHV genes and identify the CTX-M group, are used in separate PCR reactions. Any products of the correct size from the TEM and SHV PCRs are sequenced to identify the specific TEM or SHV β-lactamase. The specific CTX-M type can be identified by sequencing using CTX-M group-specific primers.

Identification of the ESBL type is appropriate for outbreak strains of ESBL-producing Enterobacterales.