Virulence genes expression profiling of different Shigella flexneri serotypes in response to sub-inhibitory concentrations of azithromycin and ciprofloxacin

Table 7 Alteration of gene expression in virulence genes of S. flexneri serotypes 4a, 3a and 2a

S. flexneri serotypes	Studied antibiotic classes	virB		ipaB		icsA		icsB
		RQ values (t₁–t₄)
		t₁	t₄	t₁	t₄	t₁	t₄	t₁	t₄
4a	Azithromycin	0.6285 ± 1	0.2526 ± 0.3	0.6736 ± 0.08	0.3686 ± 0.1	0.5864 ± 0.1	2.1214 ± 1.9	3.4462 ± 16	0.1005 ± 0.3
3a	Ciprofloxacin	21.112 ± 14.95	0.0103 ± 0.001	1.2527 ± 0.9	3.1167 ± 1.5	1.6472 ± 0.6	4.2575 ± 2.1	1.6472 ± 0.6	3.5186 ± 30.49
2a	Ciprofloxacin	0.9234 ± 14.9	0.178 ± 0.3	107.63 ± 58.88	213.04 ± 199	0.0229 ± 0.007	2.4538 ± 3.2	14.123 ± 30.24	7.6741 ± 17.19

Alteration in the transcription level of the virulence genes was analyzed in infected HT-29 cells with S. flexneri serotypes 4a, 3a and 2a at mRNA level after treatment with sub-MIC concentrations of azithromycin (32 µg/mL) or ciprofloxacin (4 µg/mL). Fold changes are expressed as RQ values (2^−ΔΔct) by comparison of transcription levels between treated vs untreated cells at same conditions. Azithromycin (32 µg/mL) and ciprofloxacin (4 µg/mL) were used for treatment based on the estimated MIC values for each strain. All the assays were done in duplicate and results shown are the mean ± std of two independent experiments
VirB, virulence factor production (vir) B; IpaB, invasion plasmid antigen (ipa) B; IcsA intracellular movement (ics) A, IcsB intracellular movement (ics) B gene

ISSN: 1757-4749