Epidemiology and clinical characteristics of hospitalized patients with pandemic influenza A (H1N1) 2009 infections: the effects of bacterial coinfection.
Open accessAbstract
BACKGROUND: Numerous reports have described the epidemiological and clinical characteristics of influenza A (H1N1) 2009 infected patients. However, data on the effects of bacterial coinfection on these patients are very scarce. Therefore, this study explores the impact of bacterial coinfection on the clinical and laboratory parameters amongst H1N1 hospitalized patients. FINDINGS: This retrospective study involved hospitalized patients with laboratory-confirmed H1N1 infections (September 2009 to May 2010). Relevant clinical data and the detection of bacterial coinfection from respiratory or sterile site samples were obtained. Multiplex PCR was used to determine the co-existence of other respiratory viruses. Comparison was made between patients with and without bacterial coinfection. The occurrence of coinfection was 34%; 14 (28%) bacterial and only 3 (6%) viral. Mycoplasma pneumoniae (n = 5) was the commonest bacteria followed by Staphylococcus aureus (n = 3). In univariate analysis, clinical factors associated with bacterial coinfection were age > 50 years (p = 0.02), presence of comorbidity (p = 0.04), liver impairment (p = 0.02), development of complications (p = 0.004) and supplemental oxygen requirement (p = 0.02). Leukocytosis (p = 0.02) and neutrophilia (p = 0.004) were higher in bacterial coinfected patients. Multivariate logistic regression analysis revealed that age > 50 years and combined complications were predictive of bacterial coinfection. CONCLUSIONS: Bacterial coinfection is not uncommon in H1N1 infected patients and is more frequently noted in the older aged patients and is associated with higher rates of complications. Also, as adjunct to clinical findings, clinicians need to have a higher index of suspicion if neutrophilia was identified at admission as it may denote bacterial coinfection.
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In a retrospective study of 50 patients infected during pandemic influenza, 28% showed co/secondary bacterial infection; Mycoplasma pneumoniae was found in 10%, S. aureus in 6%, K. pneumoniae and S. pneumoniae in 4%, and M. catarrhalis, P. aeruginosa, S. pyogenes, and Streptococcus agalactiae in 2%.
“In a retrospective study of 50 patients who were infected during pandemic influenza, 28% showed co/secondary bacterial infection (Dhanoa et al., 2011). Mycoplasma pneumoniae was found in 10%, making it the most common co/secondary infecting bacteria. This was followed by S. aureus found in 6%, K. pneumoniae and S. pneumoniae found in 4% and M. catarrhalis, P. aeruginosa, S. pyogenes, and Streptoc”
From Secondary bacterial infections associated with influenza pandemics (2017) · cites this paper as Dhanoa et al., 2011
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- Authors
- Dhanoa, A., Fang, N. C., Hassan, S. S., Kaniappan, P., & Rajasekaram, G.
- Affiliations
- Monash University Malaysia (MY)
- Corresponding author
- Dhanoa, Amreeta
- Venue
- Virology Journal
- Published
- 2011-11-03
- Volume
- 8
- Issue
- 1
- Pages
- 501-501
- ISSN
- 1743-422X (ISSN-L)
- PMC
- PMC3217982
- OpenAlex
- W2137015962
- Cited by
- 45
- References
- 11
- Citations by year
- 2026: 1 · 2025: 1 · 2024: 1 · 2023: 2 · 2022: 1 · 2021: 4 · 2020: 5 · 2018: 3 · 2017: 2 · 2016: 2 · 2015: 6 · 2014: 4 · 2013: 7 · 2012: 6
- FWCI
- 4.10
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- Virology Journal (publishedVersion, cc-by)
- Europe PMC (PubMed Central) (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
- Funders
- Monash University
- Topics
- Health Sciences › Medicine › Epidemiology › Influenza Virus Research Studies
- Health Sciences › Medicine › Epidemiology › Respiratory viral infections research
- Health Sciences › Medicine › Epidemiology › Pneumonia and Respiratory Infections
- Keywords
- influenza A (H1N1) 2009, bacterial co-infection, hospitalized patients, Mycoplasma pneumoniae, Staphylococcus aureus, medical complications, neutrophilia, leukocytosis, age as risk factor, comorbidities, liver dysfunction, supplemental oxygen
- MeSH terms
- Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Bacteria, Child, Child, Preschool, Female, Humans, Infant, Influenza, Human, Male, Middle Aged, Retrospective Studies, Comorbidity, Pneumonia, Bacterial, Influenza A Virus, H1N1 Subtype, Young Adult, Pandemics, Coinfection
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