The prevalence of serious bacterial infections in infants 90 days and younger with viral respiratory tract infections

Objectives: To determine the prevalence and risk factors of serious bacterial infections (SBIs) in infants 90 days and younger with a confirmed respiratory tract infection (RTI). Methods: A retrospective cross-sectional study was carried out of infants 90 days and younger who were admitted to King Abdullah Specialized Children’s Hospital, Riyadh, Saudi Arabia, from January 2019 to December 2020, with polymerase chain reaction (PCR)-proven RTI. Cultures from the urine, blood, and cerebrospinal fluid were reviewed with the patients’ demographic information and clinical presentation. Results: Of 322 patients with a viral RTI, 21 (6.5%) had a concurrent urinary tract infection (UTI), and no patients had bacteremia or bacterial meningitis. The risk of a concurrent SBI was 4 times higher in neonates (odds ratio [OR]=4.66, 95% confidence interval [CI]: [1.32-16.47]). Previously healthy infants were at lower risk to have a SBI in comparison to those with chronic diseases or renal abnormalities (OR=0.23, 95% CI: [0.09-0.61]). In addition, male gender (OR=3.49, 95% CI: [1.07-11.38]) and abnormal urinalysis (OR=4.12, 95% CI: [1.48-11.42]) were predictors of SBIs. There was no statistically significant association between the number or type of detected viruses and SBIs. Conclusion: No cases of invasive bacterial infections were found in infants with PCR-proven viral RTIs. There is a risk of having a concurrent UTI in this cohort of patients. Neonates had a higher risk of UTIs as compared to older infants.