Risk of concurrent bacterial infection in preterm infants hospitalized due to respiratory syncytial virus infection

Abstract

Objective: To evaluate the risk of concurrent bacterial infection in preterm infants hospitalized due to respiratory syncytial virus (RSV) disease.

Patients and methods: Retrospective cohort analysis of all infants hospitalized due to RSV infection between January 1, 2001 and July 31, 2005. Patients were identified by ICD-10 diagnosis of RSV infection including codes J21.0, J21.9, J12.1, J20.5 and B97.4. Medical charts were reviewed and RSV infection had to be confirmed by positive antigen detection test on nasopharyngeal aspirates.

Results: A total of 464 infants had been hospitalized due to RSV infection and 42 (9.1%) were born<37 weeks of gestational age. Concurrent bacterial infections were diagnosed by either positive blood or urine cultures, stool culture, tracheal aspirates or smears in 4 of 42 preterm (9.5%) compared to 13 of 422 term (3.1%) infants (p=0.017, RR 3.092, CI 95% 1.251-7.641). Excluding the infants admitted to the intensive care unit (ICU) the total rate of bacterial co-infection was 1.9%. Ten of 42 preterm (23.8%) compared to 25 of 422 term (5.2%) infants were referred to ICU (p<0.001, RR 3.349, CI 95% 1.882-5.959). All preterm infants had pneumonia, and isolates were Streptococcus pneumoniae, Chlamydia pneumoniae and Streptococcus pneumoniae with Haemophilus influenzae. Mean length of stay in preterm infants with bacterial co-infection was 22.3 days compared to 10.3 days without bacterial co-infection (p<0.006).

Conclusion: The overall low risk of concurrent bacterial infection was significantly increased in preterm infants associated with prolonged hospitalization and ICU admission.