Characterization of hospital and community-acquired respiratory syncytial virus in children with severe lower respiratory tract infections in Ho Chi Minh City, Vietnam, 2010

Abstract

Background: Human respiratory syncytial virus (RSV) is an important community and nosocomial pathogen in developed countries but data regarding the importance of RSV in developing countries are relatively scarce.

Methods: During a 1-year surveillance study in 2010, we took serial samples from children admitted to the Emergency Unit of the Respiratory Ward of Children's Hospital 1 in Ho Chi Minh City, Vietnam. RSV was detected within 72 hours of admission to the ward in 26% (376/1439; RSV A: n = 320; RSV B: n = 54; and RSV A and B: n = 2). Among those negative in the first 72 hours after admission, 6.6% (25/377) acquired nosocomial RSV infection during hospitalization (RSV A: n = 22; and RSV B: n = 3).

Results: Children with nosocomial RSV infection were younger (P = 0.001) and had a longer duration of hospitalization (P < 0.001). The rate of incomplete recovery among children with nosocomial RSV infection was significantly higher than among those without (P < 0.001). Phylogenetic analysis of partial G gene sequences obtained from 79% (316/401) of positive specimens revealed the co-circulation of multiple genotypes with RSV A NA1 being predominant (A NA1: n = 275; A GA5: n = 5; B BA3: n = 3; B BA9: n = 26; and B BA10: n = 7). The RSV A GA5 and RSV B BA3 genotypes have not been reported from Vietnam, previously.

Conclusion: Besides emphasizing the importance of RSV as a cause of respiratory infection leading to hospitalization in young children and as a nosocomial pathogen, data from this study extend our knowledge on the genetic diversity of RSV circulating in Vietnam.

Keywords: nosocomial infection; phylogenetics; respiratory syncytial virus.

Figure 1

The distribution of community and nosocomial RSV cases in Ho Chi Minh City, Vietnam, during April–December 2010.

Figure 2

(A and B) Phylogenetic tree of representative Vietnamese RSV A and B from the nucleotide sequences of the C-terminal second hypervariable region of the G gene. Tree was constructed by MEGA 5.1 software using Tamura–Nei nucleotide substitution model with 1000 bootstrapping replicates. Bootstrap values greater than 50% are shown on the branch nodes. The Vietnamese strains from this study are indicated by solid rounds.