Echovirus 30 and coxsackievirus A9 infection among young neonates with sepsis in Iran

Abstract

Background and objectives: Human enteroviruses (EV) are the most common causes of neonatal sepsis-like disease. The frequencies of EV including coxsackievirus A, coxsackievirus B and Echovirus serotypes have been studied in young infants (younger than three months) with sepsis. So far, the role of enteroviruses among neonates with sepsis was not determined in Ahvaz, Iran. Therefore, this study was aimed to evaluate the frequency of EV among hospitalized young infants with clinical signs and symptoms of sepsis in Ahvaz.

Materials and methods: Blood specimens from 128 neonates (younger than 90 days), including 56 (43.75%) girls and 72 (56.25%) boys, were collected from hospitalized neonates with clinical signs and symptoms of sepsis-like symptoms. All blood samples were negative for bacterial culture. RNA was extracted from all sera and tested for detection of 5'UTR (Untranslated Region) of the EV by RT-PCR. To determine specific strains of EV, positive 5'UTR samples were further tested for detection of the VP1 region of EV by RT-PCR.

Results: Overall, 50/128 (39.06%) specimens, including 24 (48%) girls and 26 (52%) boys, were positive for EV. 21/50 (42%) specimens were positive for the VP1 region. Randomly, 8 positive VP1 were selected and sequenced. Analysis of sequencing data showed 7/21 (33.33%) samples were positive for Echovirus 30 and 1/21 (4.76%) samples were positive for CVA9.

Conclusion: The results of this survey indicate high prevalence of 39.06% of EV among young neonates with sepsis. A high prevalence of 33.3% Echoviruses 30 and a low rate of 4.76% coxsackievirus A9 infection has been observed in neonatal patients with viral sepsis. This outbreak is probably one of the first Enterovirus outbreaks to be reported in Ahvaz, Iran. The results of this survey will help to minimize unneeded use of antimicrobial drugs and reduce unnecessary hospitalization.

Keywords: Coxsackievirus; Echovirus; Enteroviruses; Sepsis.

Fig. 1.

VP1 PCR. N: Line 1: 100 bp DNA ladder, Line 2 N: Negative control; Line 4, P: Positive control; # 3, 6 to 14: Unknown samples

Fig. 2.

A: Neighbor-joining phylogenetic tree was drawn with MEGA software version 6 of the nucleotide sequences in the VP1 regions of the strains of Echo 30 isolated from patients with sepsis in Ahwaz-Iran with accession number (KX771182-94) retrieved from Gene Bank and compared with other Echo 30 isolated from other regions of the world. Iran (Ahvaz) isolates are labeled by black solid squares and, whereas the Echo 30 (KX351155) Iran (Ahvaz) prototype strain is labeled by the black solid circle. They were compared with other Echo 30 strains isolates from other regions of the world. Numbers in branches are reproducible after 1,000 bootstraps. Scale bar=2%. B: Neighbor-joining phylogenetic tree of the nucleotide sequences in the VP1 regions of the strain of coxsackievirus A9 isolated from a patient with sepsis in Ahvaz, Iran with accession number KX771195 labeled by the black solid circle. It was compared with other coxsackievirus A9 isolates from other regions of the world, Numbers in branches are reproducible after 1,000 bootstraps. Scale bar=0.1

Graph 1.

Distributions of Enterovirus among different age groups.

Graph 2.

Frequency of Enterovirus in different seasons. The GenBank accession numbers for VP1 sequences were as follows: KX771188, KX771189, KX771190, KX771191, KX771192, KX771193 and KX771194 and KX771195.