Secondary Bacterial Infections in Patients with Seasonal Influenza A and Pandemic H1N1
Table 1
Numbers of patients with seasonal influenza A and pandemic H1N1 and numbers of relevant bacteria spp. isolated from these patients. Number (% of the total).
Influenza A
H1N1
Statistical analysis
Total number of patients
352
742
Year
2005–2008
2009
Patients with bacterial samples taken
240 (68.18%)
99 (13.34%)
Patients with positive bacterial findings
33 (9.38%)
38 (5.12%)
Respiratory cultures
Patients with positive upper airway cultures*(nasopharynx/throat)
20 (5.68%)
15 (2.02%)
S. pneumoniae
10 (2.84%)
10 (1.35%)
ND
H. influenzae
5 (1.42%)
4 (0.54%)
ND
M. catarrhalis
8 (2.27%)
3 (0.40%)
ND
S. aureus
0
3 (0.40%)
ND
S. pyogenes (group A streptococci)
2 (0.57%)
0
ND
Patients with positive lower airway cultures (sputum/bronchoalveolar lavage)
13 (3.69%)
12 (1.62%)
S. pneumoniae
5 (1.42%)
(0.1%)
ND
H. influenza
2 (0.57%)
0
ND
M. catarrhalis
1 (0.28%)
1 (0.13%)
ND
S. aureus
3 (0.85%)
5 (0.67%)
ND
Coagulase negative staphylococci
0
2 (0.27%)
ND
S. dysgalactiae (group G streptococci)
0
2 (0.27%)
ND
S. pyogenes (group A streptococci)
1 (0.28%)
0
ND
Enterobacteriaceae
1 (0.28%)
1 (0.13%)
ND
Blood cultures**
All positive blood cultures
8 (2.27%)
12 (1.62%)
NS
S. pneumoniae
1 (0.28%)
4 (0.54%)
ND
S. aureus
1 (0.28%)
1 (0.13%)
ND
H. influenzae
1 (0.28%)
0
ND
Viridans streptococci
1 (0.28%)
0
ND
S. pyogenes (group A streptococci)
0
1 (0.13%)
ND
Coagulase-negative staphylococci
4 (1.14%)
6 (0.81%)
ND
Several patients had multiple findings. **One patient had multiple findings. ND: not determined; NS: not significant.
