Group B Strep information

Since GBS came up in the comment section of an earlier post, I thought I would dedicate a new post to the topic.
First, let's do the numbers:
Courtesy of Stephanie Soderblom--numbers come from this article and the CDC

* 15-40% of women are suspected to be colonized.
* 98-99% of babies born to colonized women will not become infected.
* Of those infected with early onset, 15% will die.
* Of those infected with late onset, 50% did not contract it from their mother but rather from other sources such as hospital personnel.

Taking "worse case scenario" (ie. assuming 40% of women are colonized, and 2% of those babies will become infected)--if we did not screen, did not give antibiotics, did nothing at all...
* .0225% (1 in 4444) babies would die of early onset GBS

Next, some articles:
* Mothering magazine has an article overviewing GBS and IV abx treatment.
* Prenatal screening for group B streptococcal infection: gaps in the evidence (editorial in the International Journal of Epidemiology)

Finally, I have included several research abstracts from an alternative treament for GBS colonized mothers: chlorhexidine vaginal washes. These have been found to be as effective as IV antibiotics at preventing GBS infections in babies. A vaginal wash is much easier to administer than antibiotics, less invasive, and carries fewer side effects.

Chlorhexidine vaginal flushings versus systemic ampicillin in the prevention of vertical transmission of neonatal group B streptococcus, at term.
Matern Fetal Neonatal Med 2002 Feb; 11(2):84-8. Facchinetti F, Piccinini F, Mordini S, Volpe A. Department of Gynecology, Obstetrics and Pediatric Sciences, University of Modena and Reggio Emilia, Italy.

OBJECTIVE: To investigate the efficacy of intrapartum vaginal flushings with chlorhexidine compared with ampicillin in preventing group B streptococcus transmission to neonates.
CONCLUSIONS: In this carefully screened target population, intrapartum vaginal flushings with chlorhexidine in colonized mothers display the same efficacy as ampicillin in preventing vertical transmission of group B streptococcus. Moreover, the rate of neonatal E. coli colonization was reduced by chlorhexidine.

Prevention of excess neonatal morbidity associated with group B streptococci by vaginal chlorhexidine disinfection during labor.
Lancet 1992 Jul 11;340(8811):65-9. Comment in: Lancet. 1992 Sep 26;340(8822):791; discussion 791-2. Lancet. 1992 Sep 26;340(8822):792..

Conclusion: Chlorhexidine reduced the admission rate for infants born of carrier mothers to 2.8% (RR 1.95, 95% Cl 0.94-4.03), and for infants born to all mothers to 2.0% (RR 1.48, 95% Cl 1.01-2.16; p n 0.04). Maternal S. agalactiae colonization is associated with excess early neonatal morbidity, apparently related to aspiration of the organism, that can be reduced with chlorhexidine disinfection of the vagina during labor.

Vaginal Flushing vs. IV Antibiotics
Facchinetti F, Piccinini F, Mordini B, Volpe A. “Chlorhexidine vaginal flushings versus systemic ampicillin in the prevention of vertical transmission of neonatal group B streptococcus, at term.” J Matern Fetal Med 2002 Feb;11(2):84-8.
Department of Gynecology, Obstetrics and Pediatric Sciences, University of Modena and Reggio Emilia, Modena, Italy.

OBJECTIVE: To investigate the efficacy of intrapartum vaginal flushings with chlorhexidine compared with ampicillin in preventing group B streptococcus transmission to neonates.
METHODS: This was a randomized controlled study, including singleton pregnancies delivering vaginally. Rupture of membranes, when present, must not have occurred more than 6 h previously.. Women with any gestational complication, with a newborn previously affected by group B streptococcus sepsis or whose cervical dilatation was greater than 5 cm were excluded. A total of 244 group B streptococcus-colonized mothers at term (screened at 36-38 weeks) were randomized to receive either 140 ml chlorhexidine 0.2% by vaginal flushings every 6 h or ampicillin 2 g intravenously every 6 h until delivery. Neonatal swabs were taken at birth, at three different sites (nose, ear and gastric juice).
RESULTS: A total of 108 women were treated with ampicillin and 109 with chlorhexidine. Their ages and gestational weeks at delivery were similar in the two groups. Nulliparous women were equally distributed between the two groups (ampicillin, 87%; chlorhexidine, 89%). Clinical data such as birth weight (ampicillin, 3,365 +/- 390 g; chlorhexidine, 3,440 +/- 452 g), Apgar scores at 1 min (ampicillin, 8.4 +/- 0.9; chlorhexidine, 8.2 +/- 1.4) and at 5 min (ampicillin, 9.7 +/- 0.6; chlorhexidine, 9.6 +/- 1.1) were similar for the two groups, as was the rate of neonatal group B streptococcus colonization (chlorhexidine, 15.6%; ampicillin, 12%). Escherichia coli, on the other hand, was significantly more prevalent in the ampicillin (7.4%) than in the chlorhexidine group (1.8%, p < 0.05). Six neonates were transferred to the neonatal intensive care unit, including two cases of early-onset sepsis (one in each group). CONCLUSIONS: In this carefully screened target population, intrapartum vaginal flushings with chlorhexidine in colonized mothers display the same efficacy as ampicillin in preventing vertical transmission of group B streptococcus. Moreover, the rate of neonatal E. coli colonization was reduced by chlorhexidine. Vaginal Disinfection with Chlorhexidine During Childbirth
Stray-Pedersen B, Bergan T, Hafstad A, Normann E, Grogaard J, Vangdal M. “Vaginal disinfection with chlorhexidine during childbirth.” Int J Antimicrob Agents 1999 Aug;12(3):245-51.
Department of Gynecology and Obstetrics, Aker Hospital, University of Oslo, Norway.

The purpose of this study was to determine whether chlorhexidine vaginal douching, applied by a squeeze bottle intra partum, reduced mother-to-child transmission of vaginal microorganisms including Streptococcus agalactiae (streptococcus serogroup B = GBS) and hence infectious morbidity in both mother and child. A prospective controlled study was conducted on pairs of mothers and their offspring. During the first 4 months (reference phase), the vaginal flora of women in labour was recorded and the newborns monitored. During the next 5 months (intervention phase), a trial of randomized, blinded placebo controlled douching with either 0.2% chlorhexidine or sterile saline was performed on 1130 women in vaginal labour. During childbirth, bacteria were isolated from 78% of the women. Vertical transmission of microbes occurred in 43% of the reference deliveries. In the double blind study, vaginal douching with chlorhexidine significantly reduced the vertical transmission rate from 35% (saline) to 18% (chlorhexidine), (P < 0.000 1, 95% confidence interval 0.12-0.22). The lower rate of bacteria isolated from the latter group was accompanied by a significantly reduced early infectious morbidity in the neonates (P < 0.05, 95% confidence interval 0.00-0.06). This finding was particularly pronounced in Str. agalactiae infections (P < 0.0 1). In the early postpartum period, fever in the mothers was significantly lower in the patients offered vaginal disinfection, a reduction from 7.2% in those douched using saline compared with 3.3% in those disinfected using chlorhexidine (P < 0.05, 95% confidence interval 0.01-0.06). A parallel lower occurrence of urinary tract infections was also observed, 6.2% in the saline group as compared with 3.4% in the chlorhexidine group (P < 0.01, 95% confidence p interval 0.00-0.05). This prospective controlled trial demonstrated that vaginal douching with 0.2% chlorhexidine during labour can significantly reduce both maternal and early neonatal infectious morbidity. The squeeze bottle procedure was simple, quick, and well tolerated. The beneficial effect may be ascribed both to mechanical cleansing by liquid flow and to the disinfective action of chlorhexidine. Vaginal Chlorhexidine during labor
Burman LG, Christensen P, Christensen K, Fryklund B, Helgesson AM, Svenningsen NW, Tullus K. “Prevention of excess neonatal morbidity associated with group B streptococci by vaginal chlorhexidine disinfection during labour. The Swedish Chlorhexidine Study Group.” Lancet 1992 Jul 11;340(8811):65-9. Comment in: Lancet. 1992 Sep 26;340(8822):791; discussion 791-2. Lancet. 1992 Sep 26;340(8822):792.
National Bacteriological Laboratory, Stockholm, Sweden.

Streptococcus agalactiae transmitted to infants from the vagina during birth is an important cause of invasive neonatal infection. We have done a prospective, randomised, double-blind, placebo-controlled, multi-centre study of chlorhexidine prophylaxis to prevent neonatal disease due to vaginal transmission of S agalactiae. On arrival in the delivery room, swabs were taken for culture from the vaginas of 4483 women who were expecting a full-term single birth. Vaginal flushing was then done with either 60 ml chlorhexidine diacetate (2 g/l) (2238 women) or saline placebo (2245) and this procedure was repeated every 6 h until delivery. The rate of admission of babies to special-care neonatal units within 48 h of delivery was the primary end point. For babies born to placebo-treated women, maternal carriage of S agalactiae was associated with a significant increase in the rate of admission compared with non-colonised mothers (5.4 vs 2.4%; RR 2.31, 95% CI 1.39-3.86; p = 0.002). Chlorhexidine reduced the admission rate for infants born of carrier mothers to 2.8% (RR 1.95, 95% CI 0.94-4.03), and for infants born to all mothers to 2.0% (RR 1.48, 95% CI 1.01-2.16; p = 0.04). Maternal S agalactiae colonisation is associated with excess early neonatal morbidity, apparently related to aspiration of the organism, that can be reduced with chlorhexidine disinfection of the vagina during labour.

Chlorhexidine Gel
Kollee LA, Speyer I, van Kuijck MA, Koopman R, Dony JM, Bakker JH, Wintermans RG. “Prevention of group B streptococci transmission during delivery by vaginal application of chlorhexidine gel.” Eur J Obstet Gynecol Reprod Biol 1989 Apr;31(1):47-51.
Department of Paediatrics, University Hospital, Nijmegen, The Netherlands.

In a prospective study in 227 parturients, carriership of group B streptococci was established to be 25%. In carriers, transmission of streptococci to the newborn occurred in 50%. 10 ml of a chlorhexidine gel containing hydroxypropylmethylcellulose was introduced into the vagina during labor in 17 parturients, who were known to be carriers of group B streptococci from the first trimester of pregnancy. In none of the newborns from these mothers colonization by group B streptococci did occur. Vaginal application of chlorhexidine may prevent transmission of group B streptococci, and serve as an alternative to intrapartum prophylaxis using antibiotics. A large multicenter randomized controlled study should be performed to confirm this hypothesis.

Chlorhexidine before rupture of membranes
Christensen KK, Christensen P, Dykes AK, Kahlmeter G. “Chlorhexidine for prevention of neonatal colonization with group B streptococci. III. Effect of vaginal washing with chlorhexidine before rupture of the membranes.” Eur J Obstet Gynecol Reprod Biol 1985 Apr;19(4):231-6.

A single vaginal washing with 2 g/l of chlorhexidine was performed before rupture of the membranes in 19 parturients who were urogenital carriers of group B streptococci (GBS). Two (11%) of the infants became colonized immediately after birth, in contrast to 16 of 41 (39%) infants to controls (P = 0.02). A significant reduction of GBS colonization of the ear (P = 0.02) and umbilicus (P = 0.01) was noted. Taken together, 2 of 57 (4%) cultures obtained at birth were positive in the chlorhexidine group, in contrast to 30 of 123 (24%) among the controls (P less than 0.01). These findings raise hope for the design of a simple washing procedure which might prevent serious infections in the early neonatal period with GBS but also with other chlorhexidine-sensitive organisms.