Abstract
BackgroundWe aimed to investigate the clinical characteristics and influencing factors of severe influenza A virus pneumonia complicated by gram-negative bacterial infection in children.MethodsWe retrospectively analysed data from 43 paediatric patients with severe influenza A virus pneumonia who had been treated at our hospital. The patients were divided into observation (28 patients) and control (15 patients) groups based on whether they had a coinfection with gram-negative bacteria. The clinical data of the two groups were compared, and multivariate regression analysis was performed.ResultsThe mean age in the observation group was 2.5 ± 1.53 years; 26 (92.86%) patients were aged ≤5 years, and 11 (39.3%) had underlying diseases. The mean age in the control group was 4.07 ± 2.11 years; 10 (66.67%) patients were aged ≤5 years, and 2 (13.33%) had underlying diseases. The differences in age and the proportion of children with underlying diseases were statistically significant (P < 0.05). The observation group had a longer duration of fever, higher number of patients with fever lasting ≥7 days and higher incidence of gasping, with statistically significant differences (P < 0.05). The C-reactive protein level, procalcitonin level, platelet count and monocyte count in the observation group were significantly higher than those in the control group (P < 0.05). Among the gram-negative bacterial coinfections in the observation group, coinfections with Haemophilus influenzae (21 cases, 75%) and Moraxella catarrhalis (7 cases, 25%) were predominant. The observation group had a higher proportion of paediatric intensive care unit admissions and longer hospital stays than the control group. Additionally, significantly fewer patients in the observation group received neuraminidase inhibitor antiviral therapy within 48 h (P < 0.05). In the observation group, all H. influenzae isolates were sensitive to ceftriaxone, cefotaxime and meropenem, while resistance rates to ampicillin, trimethoprim-sulfamethoxazole, cefuroxime and ampicillin/sulbactam were 60.4%, 75%, 27.8% and 6.2%, respectively. All M. catarrhalis isolates were sensitive to ampicillin/sulbactam, amoxicillin/sulbactam and ciprofloxacin, whereas resistance rates to ampicillin and trimethoprim-sulfamethoxazole were 67.9% and 10.7%, respectively.ConclusionSevere influenza A virus pneumonia complicated by gram-negative bacterial infection is more common in children aged <5 years. Younger age and the presence of underlying diseases increase the likelihood of gram-negative bacterial coinfection. Persistent fever, wheezing and significant elevations in C-reactive protein level, procalcitonin level, platelet count and monocyte count are important early warning signs for the clinical identification of gram-negative bacterial infection.