Overtreating or underdiagnosing invasive pulmonary aspergillosis (IPA) in critically ill H1N1 patients: who is right?

Bacterial Co- or Superinfection in Patients Treated in Intensive Care Unit with COVID-19- and Influenza-Associated Pneumonia

Viral pneumonia is frequently complicated by bacterial co- or superinfection (c/s) with adverse effects on patients' outcomes. However, the incidence of c/s and its impact on the outcomes of patients might be dependent on the type of viral pneumonia. We performed a retrospective observational study in patients with confirmed COVID-19 pneumonia (CP) or influenza pneumonia (IP) from 01/2009 to 04/2022, investigating the incidence of c/s using a competing risk model and its impact on mortality in these patients in a tertiary referral center using multivariate logistic regressions. Co-infection was defined as pulmonary pathogenic bacteria confirmed in tracheal aspirate or bronchoalveolar lavage within 48 h after hospitalization. Superinfection was defined as pulmonary pathogenic bacteria detected in tracheal aspirate or bronchoalveolar lavage 48 h after hospitalization. We examined 114 patients with CP and 76 patients with IP. Pulmonary bacterial co-infection was detected in 15 (13.2%), and superinfection was detected in 50 (43.9%) of CP patients. A total of 5 (6.6%) co-infections (p = 0.2269) and 28 (36.8%) superinfections (p = 0.3687) were detected in IP patients. The overall incidence of c/s did not differ between CP and IP patients, and c/s was not an independent predictor for mortality in a study cohort with a high disease severity. We found a significantly higher probability of superinfection for patients with CP compared to patients with IP (p = 0.0017).

Bacterial pneumonia as an influenza complication

PURPOSE OF REVIEW

The pathogenesis and impact of coinfection, in particular bacterial coinfection, in influenza are incompletely understood. This review summarizes results from studies on bacterial coinfection in the recent pandemic influenza outbreak.

RECENT FINDINGS

Systemic immune mechanisms play a key role in the development of coinfection based on the complexity of the interaction of the host and the viral and bacterial pathogens. Several studies were performed to determine the point prevalence of bacterial coinfection in influenza. Coinfection in influenza is frequent in critically ill patients with Streptococcus pneumoniae being the most frequent bacterial pathogen and higher rates of potentially resistant pathogens over the years.

SUMMARY

Bacterial pneumonia is certainly an influenza complication. The recent epidemiology findings have helped to partially resolve the contribution of different pathogens. Immunosuppression is a risk factor for bacterial coinfection in influenza, and the epidemiology of coinfection has changed over the years during the last influenza pandemic, and these recent findings should be taken into account during present outbreaks.

Higher mortality of severe influenza patients with probable aspergillosis than those with and without other coinfections

BACKGROUND/PURPOSE

Aspergillus-associated infection might comprise up to 23-29% of severe influenza patients from the community throughout stay in an intensive care unit (ICU). In Taiwan, cases of severe influenza with aspergillosis are increasingly reported. Therefore, we describe the relative risk of mortality among severe influenza patients with aspergillosis and other coinfections compared to severe influenza patients without Aspergillus coinfections.

METHODS

We retrospectively reviewed 124 adult patients with severe influenza in a tertiary medical center in southern Taiwan from January 2015 through March 2016. The definition of probable aspergillosis required abnormal radiological findings and positive Aspergillus galactomannan (GM) antigen and/or Aspergillus isolation.

RESULTS

Probable aspergillosis (detected throughout the whole course) and other coinfections (only community-acquired) were diagnosed in 21 (17%) and 38 (31%) of all patients respectively. Klebsiella pneumoniae (36.8%), Pseudomonas aeruginosa (31.6%) and Staphylococcus aureus (31.6%) were the most frequent isolates of other coinfections. In-ICU mortality of Aspergillus group (66.7%) was significantly higher than other coinfections (23.7%, p = 0.001) or control group without coinfections (15.4%, p < 0.001), with significant odds ratios after adjusting for important variables. The factor of GM index ≥0.6 had a 19.82 (95% CI, 4.91 to 80.07, p < 0.0001) odds of expiring in an ICU among the Aspergillus group.

CONCLUSION

Dual Aspergillus and influenza infection is emerging in southern Taiwan. Meanwhile, community-acquired P. aeruginosa should be listed in the common copathogens with severe influenza. The 67% mortality linked to aspergillosis highlights the need for physicians to focus attention on patients with GM ≥ 0.6.

Concomitant presence of Aspergillus fumigatus and Stenotrophomonas maltophilia in the respiratory tract: a new risk for patients with liver disease?

Concomitant lung colonization by Aspergillus fumigatus and Stenotrophomonas maltophilia was reported mainly in patients with cystic fibrosis (CF) and immunocompromised patients. The aim of the study was to assess the frequency of co-culture of A. fumigatus and S. maltophilia in respiratory samples of hospitalized patients, and to determine its associated factors. Between 2007 and 2011, all patients who had A. fumigatus in their respiratory samples were retrospectively enrolled in the study. Their clinical and laboratory data, including the presence of S. maltophilia in a respiratory sample, were collected within the same month. Of the 257 enrolled patients (372 respiratory samples), 71 % were immunocompromised and 32 % had chronic respiratory disease. S. maltophilia was isolated within the same month in 20 patients (7.8 %). In the univariate analysis, factors associated with concomitant culture of A. fumigatus and S. maltophilia were liver disease (P = 0.009), orotracheal intubation (P = 0.001), ventilator-associated pneumonia (P = 0.006), central venous catheter (P = 0.003), parenteral nutrition (P = 0.008) and culture of Pseudomonas aeruginosa in respiratory samples (P = 0.002). In the multivariate analysis, the simultaneous presence of P. aeruginosa in the respiratory tract (odds ratio (OR) = 3.19, 95 % confidence interval (CI) 1.11-9.14, P = 0.031), liver disease (OR = 3.92, 95 % CI 1.32-11.62, P = 0.014) and orotracheal intubation (OR = 3.42, 95 % CI 1.17-9.96, P = 0.024) were independently associated with the co-culture of S. maltophilia and A. fumigatus. Factors independently associated with the concomitant culture of A. fumigatus and S. maltophilia were identified. These results support a future prospective study focusing on liver disease and its complications.