Why the discovery of adherent-invasive Escherichia coli molecular markers is so challenging?

Table 4 Genetic elements more frequently found in strains from the adherent-invasive Escherichia coli pathotype and suggested as putative adherent-invasive Escherichia coli molecular markers

Marker	Group of study (n)		Prevalence (%)		Sensitivity (%)	Specificity (%)	Accuracy (%)
	AIEC	non-AIEC	AIEC	non-AIEC
pduC[31]1	24	25	50	20	50	80	65
lpfA[31]1	24	25	71	20	71	80	75
29 SNPs[33]2	4	1307	100	4	-	-	-
lpfA + gipA[39]	35	103	31	0	31	100	83
3 genomic regions[32]3	14	6	79	0	79	100	85
chuA[13]4	15	37	93	59	93	41	56
SNP algorithm[36]	22	29	-	-	82	86	84
pic + ampR[38]	22	27	86	33	86	67	75

¹This strain collection was mainly formed by strains from A and B1 phylogroup (14 A, 16 B1, 10 B2 and 9D).

²Only B2 strains were included. In this case, the non-AIEC group included commensal and ExPEC strains.

³Only present in B2 AIEC strains. The strains’ phylogroup were: AIEC: 1 A, 1 B1, 10 B2, 1 D and 1 F; non-AIEC: 2 A, 2 B1 and 2 B2.

⁴Strain collection with mainly B2 and D strains (11 A, 5 B1, 18 B2 and 18 D). AIEC: Adherent-invasive Escherichia coli.