Genetic and Antigenic Characterization of Enterovirus 71 in Ho Chi Minh City, Vietnam, 2011

<div><p>Enterovirus 71 (EV71) frequently causes fatal infections in young children in Asia. In 2011, EV71 epidemics occurred in southern Vietnam. We conducted genetic and antigenic analysis of the EV71 isolates and found that 94% of them were genotype C4a related to two lineages circulating in China and 6% were genotype C5 which have circulated in Vietnam since 2003. Antigenic variants were not detected. EV71 vaccines are being developed. Longitudinal enterovirus surveillance data are critical to formulate vaccination policy in Vietnam.</p> </div

Phylogenetic relationships of EV71 viruses isolated in this study and reference strains using VP1 sequences (A) and full genomes (B).

<p>Backgrounds of the EV71 viruses genotyped in this study and the reference viruses were provided in Table 1 and Table S1 [15], respectively. The prototype coxsackievirus A16 (CA16G10) was used as the outgroup virus. The phylogenetic tree was constructed using the neighbor-joining method. Bootstrap values (>70%) are shown as percentage derived from 1,000 sampling at the nodes of the tree. Scale bar denotes number of nucleotide substitutions per site along the branches. Red dot indicates the viruses isolated and sequenced in this study.</p

SimPlot analysis of EV71 C5 virus isolated in HCM City, Vietnam, 2011.

<p>The query virus is HCM84-VNM-2011 and four potential parental (EV71 genotype C1, C2 and C3, and CA8) viruses identified through BLAST and phylogenetic analysis and six reference viruses were selected for the SimPlot analysis.</p

Clinical characteristics and laboratory values of children on admission, and outcome

†<p>Date of vaccination unless otherwise stated.</p>‡<p>HBV: Hepatitis B virus. Both received Euvax B™; MMR: Measles, Mumps, Rubella. All received Priorix™; varicella: Varilrix^R.</p>§<p>swelling at injection site beyond the expected after routine vaccination.</p>∥<p>Inotropes used were dopamine, dobutamine, noradrenaline.</p>**<p>MRSA: methicillin-resistant <i>Staphylococcus aureus</i>. NA denotes not available, a plus sign positive or present, and a minus sign negative or absent.</p>*<p>Normal ranges are as follows: hemoglobin concentration, 105–135 g/L; leukocyte count, 6 to 17.5·10⁹/L; platelet count, 150 to 400·10⁹/L; alanine aminotransferase (ALT) level, below 37 U/L; aspartate aminotransferase (AST) level, below 40 U/L; creatine phosphokinase (CK) below 200 U/L; serum creatinine concentration, 18–80 µmol/L;</p

Key virulence and resistance genes in isolates HCM3A, HT2001 751, and MW2 as detected by microarray.

*<p>Confirmed with PCR and/or sequencing</p>**<p>Microarray data cannot conclusively prove the location of a gene. Assignation to a MGE is based on known location of that gene in other sequenced strains.</p><p><i>hla</i>, α-haemolysin; <i>hlgACB</i>, γ-haemolysin; <i>hld</i>, δ-haemolysin; <i>clf</i>, clumping factors; ST, sequence type using MLST; <i>cap8</i>, capsule type 8; <i>sasG</i>, accumulation associated protein SA2285; <i>coa</i> M0206v, coagulase with four types described; <i>sasA</i>, haemagglutinin like gene which can contain an insert; <i>cna</i>, collagen binding protein; <i>sdr</i>, serine aspartate repeat proteins; <i>fnbpA</i>, fibronectin binding protein with three types described; <i>lytN</i>, cell wall hydrolase; <i>agr</i>, accessory gene regulator with 4 classes described; <i>trap</i>, target of RNAIII activating protein with 2 types described; <i>sarT</i>, staphylococcal accessory regulator T; MGE, mobile genetic element; SCC, staphylococcal cassette chromosome; <i>mec</i>, methicillin resistance; <i>ccr</i>, cassette chromosome recombinase with 3 types described; <i>far1</i>, putative fusidic acid resistance; <i>PV-luk</i>, Panton Valentine leukocidin; <i>seg</i>, enterotoxin G; <i>sak</i>, staphylokinase; <i>sea</i>, enterotoxin A; <i>sek</i>, enterotoxin K; <i>seb</i>, enterotoxin B; <i>sec</i>, enterotoxin C; <i>bla</i>, β-lactamase; <i>cad</i>, cadmium resistance; <i>ars</i>, arsenic resistance; <i>bacteriocin</i>, putative bacteriocin gene SAR0694-5; - denotes gene not detected; #, phage unrelated to PV-<i>luk</i> phage in MW2.</p

Rapidly progressive soft tissue infection after vaccination.

<p>Severe tissue necrosis around vaccination site in Child 4, two days following vaccination with MMR. MRSA was cultured from wound fluid.</p