Extended-spectrum β-lactamase (ESBL) gene PCR and sequencing
|Lab name||Antibiotic Reference Laboratory|
|Lab location||Kenepuru Science Centre, Porirua|
|Test name||Extended-spectrum β-lactamase (ESBL) gene PCR and sequencing|
|Requested for surveillance||no|
|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|
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 Enterobacteriaceae.