Bacterial codetection tied to better outcomes in ventilated infants with bronchiolitis

Bacterial respiratory tract infection normally occurs in infants requiring early intubation in the emergency department (ED) for viral bronchiolitis, according to a study. However, respiratory bacterial codetection appears to shorten the duration of mechanical ventilation (MV) and length of stay (LOS) of these patients in the intensive care unit (ICU).

“Early antibiotics may contribute to these outcomes, but further multicentre studies are needed to understand the role of codetection and antibiotics on bronchiolitis outcomes,” the researchers said.

More than half (52 percent) of the 149 patients enrolled had bacterial codetection. Adjusted analysis revealed shorter MV duration (adjusted relative risk [aRR], 0.819, 95 percent confidence interval [CI], 0.69‒0.98; marginal mean duration, 5.31 days vs 6.48 days without codetection) in infants with codetection. [Pediatr Infec Dis J 2024;43:117-122]

In addition, patients with codetection had a shorter stay in the ICU (aRR, 0.806, 95 percent CI, 0.69‒0.94; marginal mean LOS, 6.9 vs 8.57 days without codetection).

Interestingly, the association between codetection and MV duration was more evident in patients treated early with antibiotics (less than the median time) than in those treated later (aRR, 0.738, 95 percent CI, 0.56‒0.95 for earlier vs aRR, 0.92, 95 percent CI, 0.70‒1.18 for later).

“In our cohort of infants requiring ED intubation for bronchiolitis, over half of the patients had bacterial codetection—a finding consistent with prior studies,” the researchers said. [Thorax 2006;61:611-615; Pediatr Crit Care Med 2010;11:390-395; Eur J Pediatr 2005;164:93-98]

“Surprisingly, bacterial codetection was not associated with longer duration of MV but was, in fact, associated with a nearly 20-percent shorter duration of MV. This finding differed from our expectation as well as from prior studies reporting on the impact of bacterial codetection or coinfection,” they added. [J Asthma 2015;52:268-272; BMC Infect Dis 2019;19:938]

Early antibiotics

On the other hand, prematurity, a positive nonrespiratory culture (eg, bacteraemia), and respiratory syncytial virus (RSV) infection independently correlated with longer MV duration and ICU LOS.

“We were unable to examine the impact of receiving antibiotics because all patients received early antibiotics, and we also were unable to evaluate the impact of pneumococcal vaccination because these data were not available,” the researchers said.

It remains unclear why codetection leads to better outcomes, but the fact that this association is mainly seen in infants who received antibiotics early after their ED presentation indicates the important role played by antibacterial medication in changing the course of the disease, according to the researchers.

Such findings support those of a recent study by Shein and colleagues, which showed that infants intubated for RSV bronchiolitis who received early antibiotics tended to have better outcomes. [Pediatr Crit Care Med 2019;20:101-109]

The current single-centre retrospective cohort study involved children aged <2 years who required intubation in the ED for bronchiolitis from 2012 to 2017 and had viral testing plus a lower respiratory culture obtained.

The researchers used multivariable gamma regression to examine the effect of bacterial codetection (positive respiratory culture plus moderate or many polymorphonuclear neutrophils on Gram stain) on MV duration and ICU LOS.