Group B streptococcal carriage, antimicrobial susceptibility, and virulence related genes among pregnant women in Alexandria, Egypt

Peer review under responsibility of Alexandria University Faculty of Medicine.

Available online 21 February 2017

Figures & data

Fig. 1 Flowchart of laboratory processing of vaginal and rectal swabs for isolation and identification of GBS in the study.

Table 1 Primer sequences used in the study.

Gene	Primer sequence	bp
scpB	scp F: ACAACGGAAGGCGCTACTGTTC scp R: ACCTGGTGTTTGACCTGAACTA	255
bac	bac F: TGT AAA GGA CGA TAG TGT GAA GAC bac R: CAT TTG TGA TTC CCT TTT GC	530
bca	bca F: CAG GAG GGG AAA CAA CAG TAC bca R: GTA TCC TTT GAT CCA TCT GGA TAC G	183
rib	rib F: CAG GAA GTG CTG TTA CGT TAA AC rib R: CGT CCC ATT TAG GGT TCT TCC	369

Table 2 The socio-demographic factors associated with GBS colonization in the 200 pregnant women.

	Total n = 200	GBS positive N = 53		P value
		No	%
Mean age^*	26.02 ± 4.72	25.43 ± 2.90		0.467
<20	12	1	8.3	0.010
20–30	155	49	31.6
>30	33	3	9.1
Gestational age
35 w	54	7	13.0	0.002
36 w	55	11	20.0
37 w	91	35	38.5
Number of previous pregnancies
Primigravida	64	20	31.3	0.296
Multigravida	136	33	24.3
Number of antenatal visits
4 times	6	–	–	<0.001
5 times	37	7	18.9
6 times	59	23	39.0
7 times	56	23	41.1
8 times	30	–	–
9 times	12	–	–
Contraceptive method used
Condom	39	26	66.7	<0.001
Loop	57	7	12.3
Oral contraceptives	3	–	–
None	101	20	19.8

* Age is presented in mean ± SD.

Fig. 2 The antibiotic sensitivity pattern of GBS carrier isolates.

Fig. 3 Agarose gel electrophoresis of PCR of GBS virulence genes. Lane 8 = DNA ladder. Lane 1, 2, 11 = Negative samples. Lane 3, 4, 9, 10 = scpB positive isolates (255 bp). Lane 5, 6, 7, 13 = rib positive isolates (369 bp), Lane 12 = bac positive isolate (530 bp). Lane 14, 15 = Negative controls.

Table 3 The frequency of virulence genes (scpB, bac, bca and rib) among GBS isolates.

Virulence genes	No	%
scpB	53	100
rib	42	79.2
bac	19	35.8
bca	0	0
scpB+/rib−/bac−/bca−	11	20.7
scpB+/rib+/bac−/bca−	23	43.4
scpB+/rib+/bac+/bca−	19	35.8

Table 4 The distribution of GBS isolates resistant to each antibiotic according to virulence genes.

Virulence factor	No of isolates resistant to each antibiotic (%)
	Azithromycin	Erythromycin	Clindamycin	Levofloxacin
scpB gene	15/15 (100%)	12/12 (100%)	8/8 (100%)	23/23 (100%)
rib gene	4/15 (26.7%)	4/12 (33.3%)	4/8 (50%)	11/23 (47.8%)
bac gene	0	0	0	8/23 (34.8%)
bca	0	0	0	0
scpB+/rib−/bac−/bca−	11/15 (73.3%)	8/12 (66.7%)	4/8 (50%)	4/23 (17.4%)
scpB+/rib+/bac−/bca−	4/15 (26.7%)	4/12 (33.3%)	4/8 (50%)	11/23 (47.8%)
scpB+/rib+/bac+/bca−	0	0	0	8/23 (34.8%)
Total	15	12	8	23