Etiology of community-acquired pneumonia and diagnostic yields of microbiological methods: a 3-year prospective study in Norway

Table 3 Viral findings and contribution of different methods to diagnostic yield in the study population

Pathogen	No. (%) of patients with positive findings(n = 267)	Real-time PCR		Serology(n = 263)
Pathogen	No. (%) of patients with positive findings(n = 267)	NP swab(n = 262)^a	OP swab(n = 262)^b	Serology(n = 263)
Influenza viruses^c	40 (15)	15	3	22
Rhinovirus	32 (12)	27	5	NA
Parainfluenza viruses^d	8 (3)	5	3	NA
Respiratory syncytial virus^e	7 (3)	7	-	NA
Metapneumovirus	7 (3)	4	3	NA
Enterovirus	5 (2)	5	-	NA
Adenovirus	1 (0.4)	1	-	NA
Total^f	92 (34)	64	14	22

Note: Data are number of patients, unless otherwise stated, whose infections were etiologically established by use of a particular method listed in descending order of specificity (NP vs. OP swab PCR are generally considered equally). Additional patients had etiology established by use of different methods; e.g., infection with influenza viruses was established by use of OP swab in 3 additional patients whose etiology was not established by NP swab etc. PCR, polymerase chain reaction; NP, nasopharynx; OP, oropharynx; NA, not applicable.
^aOf 262 patient samples, 240 revealed valid results for detection of all viruses (except from influenza viruses of which 239 samples revealed valid results).
^bOf 262 patient samples, 238 revealed valid results for detection of all viruses.
^cInfluenza A virus (13 cases of which 2 cases were H1N1 positive), Influenza B virus (5 cases). 1 case tested positive for both influenza A and B viruses by use of serology.
^dParainfluenza virus type 1 (1 case), type 2 (2 cases), type 3 (5 cases).
^eRespiratory syncytial virus A (5 cases), 2 cases were undefined.
^fNo. of patients does not add up to no. of pathogens because some patients had multiple pathogens detected: a total of 100 viruses were detected in 92 patients.

ISSN: 1471-2334