Published online Oct 16, 2022. doi: 10.12998/wjcc.v10.i29.10583
Peer-review started: February 16, 2022
First decision: April 10, 2022
Revised: April 20, 2022
Accepted: August 14, 2022
Article in press: August 14, 2022
Published online: October 16, 2022
Necrotizing enterocolitis (NEC) is a multifactorial disease that predominantly affects premature neonates. Intestinal dysbiosis plays a critical role in NEC pathogenesis in premature neonates. The main risk factor for NEC in term infants is mesenteric hypoperfusion associated with ductal-dependent congenital heart disease (CHD) that eventually leads to intestinal ischemia. The incidence of NEC in neonates with critical CHD is 6.8%-13%. However, the role of the intestinal microbiome in NEC pathogenesis in infants with ductal-dependent CHD remains unclear.
A male term neonate with right atrial isomerism underwent modified Blalock-Taussig shunt placement on the 14th day of life and had persistent mesenteric hypoperfusion after surgery. The patient had episodes of NEC stage IIA on the 1st and 28th days after cardiac surgery. Fecal microbial composition was analyzed before and after cardiac surgery by sequencing region V4 of the 16S rRNA gene. Before surgery, species belonging to genera Veillonella and Clostridia and class Gammaproteobacteria were detected, Bifidobacteriaceae showed a low abundance. The first NEC episode was associated with postoperative hemodynamic instability, intestinal ischemia-reperfusion injury during cardiopulmonary bypass, and a high abundance of Clostridium paraputrificum (Clostridium sensu stricto I) (56.1%). Antibacterial therapy after the first NEC episode resulted in increased abundance of Gammaproteobacteria, decreased abundance of Firmicutes, and low alpha diversity. These changes in the microbial composition promoted the growth of Clostridium sensu stricto I (72.0%) before the second NEC episode.
A high abundance of Clostridium sensu stricto I and mesenteric hypoperfusion may have contributed to NEC in the present case.
Core Tip: Right atrial isomerism is associated with severe congenital heart disease, abnormal arrangement of internal organs, and asplenia/spleen hypoplasia. Infants with right atrial isomerism palliated with the systemic-to-pulmonary shunt have a “diastolic steal” of mesenteric blood flow, which increases the risk of necrotizing enterocolitis (NEC). The role of the microbiome in cardiogenic NEC remains unclear. This case report highlights possible interactions between dynamic changes in the fecal microbiome before and after cardiac surgery and development of recurrent NEC, based on hemodynamic changes, mesenterial perfusion, and antibacterial treatment in an asplenic infant with right atrial isomerism who underwent palliative cardiac surgery.