Long-term Impact of Oral Azithromycin Taken by Gambian Women During Labor on Prevalence and Antibiotic Susceptibility of Streptococcus pneumoniae and Staphylococcus aureus in Their Infants: Follow-up of a Randomized Clinical Trial

Background

Oral azithromycin given to women in labor decreases maternal and neonatal bacterial carriage but increases azithromycin-resistant bacteria during at least 4 weeks following the intervention. We assessed the prevalence of bacterial carriage and azithromycin resistance 12 months after treatment among study infants.

Methods

Nasopharyngeal swabs (NPSs) were collected between November 2014 and May 2015 from children aged 11-13 months whose mothers had received azithromycin or placebo during labor. Streptococcus pneumoniae and Staphylococcus aureus were isolated using conventional microbiological methods. Antibiotic susceptibility was determined by disk diffusion and confirmed by Etest or VITEK-2.

Results

NPSs were collected from 461 children. The prevalence of S. pneumoniae and S. aureus was similar between children from the azithromycin and placebo arms (85.0% vs 82.1%; odds ratio [OR], 1.23 [95% confidence interval {CI}, .73-2.08] for S. pneumoniae and 21.7% vs 21.3%; OR, 1.02 [95% CI, .64-1.64] for S. aureus). Prevalence of azithromycin-resistant S. pneumoniae was similar in both arms (1.8% vs 0.9% in children from the azithromycin and placebo arms, respectively; OR, 2.10 [95% CI, .30-23.38]); resistance to other antibiotics was also similar between arms. For S. aureus, there was no difference in azithromycin resistance between children in the azithromycin (3.1%) and placebo (2.6%) arms (OR, 1.22 [95% CI, .35-4.47]) or resistance to any other antibiotics.

Conclusions

The higher prevalence of S. aureus azithromycin resistance observed among women treated during labor and their babies 4 weeks after treatment had waned 12 months after delivery. Azithromycin intervention did not induce other antibiotic resistance to S. pneumoniae or S. aureus.

Clinical Trials Registration

NCT01800942.

Long-lasting effect of oral azithromycin taken by women during labour on infant nutrition: Follow-up cohort of a randomized clinical trial in western Gambia

Objective

To assess the effect of administering an oral dose of 2g of azithromycin in Gambian women during labour on infant growth.

Methods

Children whose mothers had been randomized to receive either an oral dose of 2g of azithromycin or placebo during labour were visited at home at the end of infancy by trained study nurses blind to the treatment allocation. The follow-up visit of these cohorts (exposed and non-exposed to azithromycin), which was not part of the original trial design, was conducted between November 2014 and May 2015 when the infants were 11 to 13 months of age. During visits, nurses recorded anthropometrical measurements and transcribed information from the infants’ welfare cards.

Results

Four-hundred and sixty-five (79.6%) of the 584 infants aged 11–13 months at the time of the survey were recruited. The proportion of children with an age-adjusted Z-score <-2SD for mid-upper-arm circumference (MUAC) was lower among those exposed to azithromycin [1.3% versus 6.3%, OR = 0.21 95%CI (0.06,0.72), p = 0.006] and there was weak evidence of a difference in the proportion of infants with weight-for-age (WAZ) Z-score <-2SD [7.1% versus 12.1%, OR = 0.58 95%CI (0.33,1.04), p = 0.065]. For all other malnutrition indicators the proportions were similar in the exposed and un-exposed cohort.

Conclusions

Our results show that azithromycin in labour may have a beneficial effect in MUAC among children who are below the curve. Larger studies with closer follow-up are warranted.

Trial registration (main trial)

ClinicalTrials.gov Identifier NCT01800942.

Maternal colonization with Staphylococcus aureus and Group B streptococcus is associated with colonization in newborns

OBJECTIVES

Although Staphylococcus aureus and Group B streptococcus (GBS) are major causes of neonatal sepsis in sub-Saharan Africa, it is unclear how these bacteria are transmitted to the neonate.

METHODS

In a cohort of 377 Gambian women and their newborns, nasopharyngeal swabs were collected at delivery (day 0), and 3, 6, 14 and 28 days later. Breast milk samples and vaginal swabs were collected from the mother. Staphylococcus aureus and GBS were isolated using conventional microbiological methods.

RESULTS

Most women were carriers of S. aureus (264 out of 361 with all samples collected, 73.1%) at some point during follow up and many were carriers of GBS (114 out of 361, 31.6%). Carriage of S. aureus was common in all three maternal sites and GBS was common in the vaginal tract and breast milk. Among newborns, carriage of S. aureus peaked at day 6 (238 out of 377, 63.1%) and GBS at day 3 (39 out of 377, 10.3%). Neonatal carriage of S. aureus at day 6 was associated with maternal carriage in the breast milk adjusted OR 2.54; 95% CI 1.45-4.45, vaginal tract (aOR 2.55; 95% CI 1.32-4.92) and nasopharynx (aOR 2.49; 95% CI 1.56-3.97). Neonatal carriage of GBS at day 6 was associated with maternal carriage in the breast milk (aOR 3.75; 95% CI 1.32-10.65) and vaginal tract (aOR 3.42; 95% CI 1.27-9.22).

CONCLUSIONS

Maternal colonization with S. aureus or GBS is a risk factor for bacterial colonization in newborns.