Effects of Intrapartum Penicillin Prophylaxis on Intestinal Bacterial Colonization in Infants

Abstract

Early-onset group B streptococcal (GBS) infections remain a leading cause of morbidity and mortality in infants. To prevent the vertical transmission of GBS and neonatal GBS infection, guidelines recommend intrapartum penicillin or amoxicillin prophylaxis. This intrapartum antibiotic prophylaxis (IAP) is suspected to favor colonization by antibiotic-resistant bacteria. However, the effects of this prophylaxis on the patterns of acquisition of gastrointestinal bacterial flora in infants have never been studied. We collected stool samples from 3-day-old infants born to mothers who received intrapartum amoxicillin (antibiotic-exposed group; n ‫؍‬ 25) and to untreated mothers (non-antibiotic-exposed group; n ‫؍‬ 25). The groups were matched for factors known to affect intestinal microbial colonization: gestational age, type of delivery, and type of feeding. Qualitative and quantitative differential analyses of the bacterial flora in stool samples were performed. Similar numbers of infants in the non-antibiotic-exposed and antibiotic-exposed groups were colonized by aerobic bacteria and amoxicillin-resistant enterobacteria (75 and 77%, respectively) (P ‫؍‬ 0.79). In contrast, significantly fewer infants in the antibiotic-exposed group than in the non-antibiotic-exposed group were colonized by anaerobic bacteria, especially Clostridium (12 and 40%, respectively) (P < 0.05). Regarding intestinal bacterial colonization, the differences between antibiotic-exposed and non-antibiotic-exposed infants were remarkably few. The only statistically significant effect was the reduced initial bacterial colonization by Clostridium in the antibiotic-exposed group. In our study, the use of IAP did not favor colonization by ␤-lactam-resistant bacteria. However, further evaluations are required to highlight the potential risks of the widespread use of antibiotics to prevent early-onset GBS infection.

Impact of empiric antibiotic regimen on bowel colonization in neonates with suspected early onset sepsis

“…With this our findings are in accordance with Jaureguy et al who, in an intrapartum prophylaxis study, failed to demonstrate that amoxicillin selects for betalactam resistant enterobacteria [11]. At present in most countries all Enterobacteraceae but E. coli have become uniformly resistant to ampicillin [32,33], and thus it is not surprising that ampicillin and penicillin have similar influence on gut colonization with Gram-negative bacteria.…”

“…Differences in proportions were compared using Chi-square test. To compensate for the influence of other [6,7,9,11,12,[20][21][22][23][24][25][26][27][28][29][30] was performed. The study was approved by the Ethics Committee of the University of Tartu.…”

“…As for Gram negative microorganisms and Candida spp, the number of colonized patients in both treatment arms was similar but greater CDs of K. pneumonia, AR Serratia spp and Candida spp were seen in the ampicillin arm and that of AR Acinetobacter spp in the penicillin arm. Studies have shown that gut colonization of a neonate is a complex process influenced by several intrinsic and extrinsic factors [6,7,11,12,[27][28][29][30]. Thus, when evaluating the interference of early antibacterial therapy with this process the methodological considerations are of utmost importance.…”

“…Finally, also maternal, neonatal and environmental factors known to interfere with gut colonization like GA, use of broad spectrum antibiotics, severity of disease, etc. were taken into account [6,7,11,12,[27][28][29][30]. We believe that such an approach enabled us to characterize adequately the true differences of these two antibiotic regimens on bowel colonization.…”

“…Still, the study did not clarify whether the differences between the two antibiotic regimens were triggered by amoxicillin or cefotaxime or both. The use of ampicillin in intrapartum prophylaxis of group B streptococcal infection has been associated with the emergence of Escherichia coli as a major causative pathogen of EOS and probably an increase in ampicillin-resistance [6,10], but the data are not conclusive [11].…”