Mailed versus frozen transport of nasal swabs for surveillance of respiratory bacteria in remote Indigenous communities in Australia.
BACKGROUND
Surveillance programs and research for acute respiratory infections in remote Australian communities are complicated by difficulties in the storage and transport of frozen samples to urban laboratories for testing. This study assessed the sensitivity of a simple method for transporting nasal swabs from a remote setting for bacterial polymerase chain reaction (PCR) testing.


METHODS
We sampled every individual who presented to a remote community clinic over a three week period in August at a time of low influenza and no respiratory syncytial virus activity. Two anterior nasal swabs were collected from each participant. The left nare specimen was mailed to the laboratory via routine postal services. The right nare specimen was transported frozen. Testing for six bacterial species was undertaken using real-time PCR.


RESULTS
One hundred and forty participants were enrolled who contributed 150 study visits and paired specimens for testing. Respiratory illnesses accounted for 10% of the reasons for presentation. Bacteria were identified in 117 (78%) presentations for 110 (79.4%) individuals; Streptococcus pneumoniae and Haemophilus influenzae were the most common (each identified in 58% of episodes). The overall sensitivity for any bacterium detected in mailed specimens was 82.2% (95% CI 73.6, 88.1) compared to 94.8% (95% CI 89.4, 98.1) for frozen specimens. The sensitivity of the two methods varied by species identified.


CONCLUSIONS
The mailing of unfrozen nasal specimens from remote communities appears to influence the utility of the specimen for bacterial studies, with a loss in sensitivity for the detection of any species overall. Further studies are needed to confirm our finding and to investigate the possible mechanisms of effect.


BACKGROUND
Australia and New Zealand Clinical Trials Registry Number: ACTRN12609001006235.
Queensland Children's Medical Research Institute, Queensland University of Technology, Herston Road HERSTON QLD, 4029 Herston, Australia. k.ogrady@uq.edu.au.
Kerry-Ann F
KA
O'Grady
David M
DM
Whiley
Paul J
PJ
Torzillo
Theo P
TP
Sloots
Stephen B
SB
Lambert
D000293:Adolescent; D000328:Adult; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009296:Nasal Cavity / Q000382:microbiology*; D062486:Public Health Surveillance / Q000379:methods*; D060888:Real-Time Polymerase Chain Reaction; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000208:ethnology* / Q000382:microbiology*; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D055815:Young Adult