High Rates of Antimicrobial Resistance and Virulence Gene Distribution Among Shigella spp. Isolated from Pediatric Patients in Tehran, Iran

Figures & data

Table 1 Antimicrobial Resistance of Shigella Isolates from Pediatric Patients in Iran

Antibiotics	S. sonnei No. (%), n = 111	S. flexneri No. (%), n = 28	p-value	S. boydii No. (%), n = 2	Total of Shigella Strains No. (%), n =141
CTX	70 (63.1)	12 (42.8)	0.004	2 (100.0)	84 (59.6)
NA	104 (93.7)	10 (35.7)	0.00001	2 (100.0)	116 (82.3)
AMP	74 (66.7)	27 (96.4)	0.00001	2 (100.0)	103 (73.0)
SXT	111 (100.0)	26 (92.8)	0.03	2 (100.0)	139 (98.5)
LEV	12 (10.8)	4 (14.3)	0.521	0 (00.0)	16 (11.3)
CFM	69 (62.1)	13 (46.4)	0.023	2 (100.0)	84 (59.6)
MN	86 (77.5)	7 (25)	0.00001	0 (00.0)	93 (65.9)
CIP	3 (2.7)	5 (17.8)	0.0005	0 (00.0)	8 (5.7)
AZT	65 (58.6)	2 (7.1)	0.00001	0 (00.0)	67 (47.5)
MDR	86 (77.5)	13 (46.4)	0.00001	2 (100.0)	101 (71.6)

Note: Statistically significant values (P<0.05) are presented in bold.

Abbreviations: AMP, ampicillin; AZT, azithromycin; CFM, cefixime; CIP, ciprofloxacin; CTX, cefotaxime; LEV, levofloxacin; NA, nalidixic acid; MDR, multidrug resistance; MN, minocycline; SXT, trimethoprim-sulfamethoxazole.

Table 2 Antibiotic Resistance Profiles of Shigella spp. from Pediatric Diarrhetic Patients

Antibiotics Profiles	Age						Total No.
	2 Months to 5 Years			6 to14 Years
	S. sonnei No. (%)	S. flexneri No. (%)	S. boydii No. (%)	S. sonnei No. (%)	S. flexneri No. (%)	S. boydii No. (%)
CIP/AZT/CFM/LEV/MN/CTX/NA/AM/SXT	4	_	_	5	_	_	9
AZT/CFM/CTX/MN/NA/AM/SXT/LEV	20	_	_	21	_	_	41
AZT/CFM/MN/CTX/NA/AM/SXT	_	_	_	3	_	_	3
SXT/CTX/NA/MN/AM/	2	5	1	_	1	_	9
SXT/MN/NA	17	_	_	7	_	_	24

Abbreviations: AMP, ampicillin; AZT, azithromycin; CFM, cefixime; CIP, ciprofloxacin; CTX, cefotaxime; LEV, levofloxacin; NA, nalidixic acid; MDR, multidrug resistance; MN, minocycline; SXT, trimethoprim-sulfamethoxazole.

Figure 1 The minimum inhibitory concentration (MIC) of azithromycin for clinical isolates of Shigella recovered from pediatric patients in Tehran, Iran.

Table 3 Distribution of Virulence Factor Genes in 141 Shigella spp. Isolated from Pediatric Patients

Virulence Genes	S. sonnei No. (%), n = 111	S. flexneri No. (%), n = 28	S. boydii No. (%), n = 2	Total of Shigella Strains No. (%), n = 141
ipaH	111 (100.0)	28 (100.0)	2 (100.0)	141 (100.0)
ipaB	101 (90.1)	28 (100.0)	2 (100.0)	131 (92.9)
ipaC	105 (94.6)	28 (100.0)	2 (100.0)	135 (95.7)
ipaD	103 (92.8)	28 (100.0)	2 (100.0)	133 (94.3)
ipgD	88 (79.3)	24 (85.7)	2 (100.0)	114 (80.8)
Sen	107 (96.4)	26 (92.8)	2 (100.0)	135 (95.7)
virA	103 (92.8)	27 (96.4)	2 (100.0)	132 (93.6)

Table 4 Virulence Determinant Profiles of the Shigella spp. Isolated from Pediatric Patients

Shigella spp.	ipaH	ipaB	ipaC	ipaD	ipgD	Sen	virA	No. (%)
S. sonnei, n = 111	+	+	+	+	+	+	+	86 (77.5)
	+	+	+	+	–	+	+	12 (10.8)
	+	+	–	+	–	+	+	2 (1.8)
	+	–	+	–	–	+	–	3 (2.7)
	+	–	–	–	–	+	+	2 (1.8)
	+	–	–	+	–	–	–	2 (1.8)
	+	+	+	–	+	–	–	1 (0.9)
	+	–	+	+	+	+	+	1 (0.9)
	+	–	+	–	–	+	+	1 (0.9)
	+	–	+	–	–	–	–	1 (0.9)
S. flexneri, n = 28	+	+	+	+	+	+	+	24 (85.7)
	+	–	+	+	–	+	+	1 (86.0)
	+	+	+	+	–	–	+	1 (3.5)
	+	+	+	+	–	+	+	1 (3.5)
	+	+	+	–	–	–	+	1 (3.5)
S. boydii, n = 2	+	+	+	+	+	+	+	2 (100.0)